11613 research outputs found
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Optimized CO2 capture of the zeolitic imidazolate framework ZIF‑8 modified by solvent-assisted ligand exchange
No full textZeolitic imidazolate frameworks, like ZIF-8 and related structures, have shown great potential for the capture of carbon dioxide. Modifying their structure by exchanging part of the constituent organic ligands is a proven method for enhancing the capacity to absorb CO2. In this work, we performed solvent-assisted ligand exchange (SALE) on nanosized ZIF-8 (nZIF-8) with a series of functionalized imidazole derivatives (exchange percentages, after 24 h): 2-bromoimidazole (19%), 2-chloroimidazole (29%), 2-trifluoromethylbenzimidazole (4%), 2-mercaptobenzimidazole (4%), and 2-nitroimidazole (54%). The sodalite topology and porosity of nZIF-8 were maintained with all SALE modifications. Low-pressure CO2 adsorption of nZIF-8 (38.5 cm3 g–1) at STP was appreciably enhanced with all mixed-linker SALE products. Using halogenated (−Cl, −Br, and −CF3) imidazole derivatives in a 24 h SALE treatment resulted in increases between 11 and 22% in CO2 adsorption, while the thiol (−SH)- and nitro (−NO2)-functionalized SALE products led to 32 and 100% increases in CO2 uptakes, respectively. These CO2 uptakes were further optimized by varying the SALE treatment time. The SHbIm- and NO2Im-exchanged SALE products of nZIF-8 show 87 and 98 cm3 g–1 of CO2 uptakes after 60 and 120 h of SALE, respectively. These are record high CO2 adsorptions for all reported ZIF derivatives at low-pressure conditions.Publisher's versio
The effectiveness of puppetry art in changing learners’ attitudes in Natural Sciences
No full textThe declining attitudes of learners towards science over the years has been a source of concern to educationists. Researchers has shown that learners’ attitudes towards science can be influenced by the type of tool or strategy the teacher employs to deliver the lesson in the classroom. This study aims to determine the effectiveness of puppetry art as a teaching tool to change the attitudes of learners towards natural sciences within the context of the STEAM educational approach. The study was conducted at three different schools in the Motheo District of the Free State province. The participants were Grade 9 learners who were selected by random sampling and placed in three experimental and control groups. The study employed a quantitative research methodology and the experimental research design method. Data was obtained through pre-tests and post-tests using a standardised attitude survey, the Colorado Learning Attitudes about Science Survey (CLASS). Descriptive and inferential statistics were used in the analysis of the data, while the analysis of covariance (ANCOVA) was employed to adjust the dependent variable to remove the effects of the uncontrolled sources of variation represented by the concomitant variable in the test of the null hypothesis. The results showed that the learners’ personal interest, conceptual understanding and applied conceptual understanding categories regarding their attitude towards natural sciences were positively influenced by the application of the teaching tool. The learners’ sense-making effort, general problem-solving confidence, and sophistication, as well as the real-world connection categories regarding their attitude towards natural sciences were not influenced by the teaching tool. Further research is needed to focus on ways to improve the implementation of the application of this teaching tool for improved learner performance, as well as their change in attitude towards science
The influence of anxiety and depressive symptoms on social functioning: a person-centred study among South African university students
No full textThe prevalence of comorbid anxiety and depression among university students is high and results in great impairment of (social) functioning even in subclinical groups. However, the heterogeneity of depression and anxiety profiles and how they affect South African students’ social functioning is unknown. Therefore, this cross-sectional survey study investigated the naturally occurring latent groupings formed from anxiety and depression symptoms, and their ability to distinguish levels of social functioning. Participants were a sample of 1988 university students from South Africa (69.1% female; with a mean age of 21.44 [SD = 3.094], ranging between 17 and 64 years). They completed an online survey comprising the Patient Health Questionnaire-9 (PHQ-9), the Generalised Anxiety Disorder-7 (GAD-7), and the Social Functioning Questionnaire (SFQ). Responses to anxiety and depression symptom indicator variables were subjected to latent class analysis in Mplus. The emergent classes were compared for levels of social functioning using analysis of variance (ANOVA) in SPSS. Four meaningful classes, showing different levels of symptom endorsement, emerged from the data. Class 1 (20.3%), labelled “Healthy”, had the lowest rates of comorbid depression and anxiety symptom endorsement. Class 2 (35.3%), labelled “Anxious exhaustion”, had significantly high scores for sleep disturbance, fatigue and other anxiety symptoms. Class 3 (18.3%), labelled “Anxious depression”, represented that most severely distressed members with high rates of symptom endorsement for almost all depression anxiety symptoms. Lastly, Class 4 (26.1%), labelled “Low distress” was found to have low levels of endorsement of sleep disturbance, excessive worry and irritability. Although depressive symptoms were found to be more prevalent in this university student sample, it was the classes (class 2 and 3) with the endorsement of higher levels of anxiety symptoms that were found to have poorer social functioning. Furthermore, specific symptoms such as worry and fear, in addition to depression, may be key contributors to poor social functioning among students. The inclusion of students with no diagnoses, as well as a non-clinical population, allowed for the assessment of symptom presentation and severity below the diagnostic cut-offs for depression and anxiety. The findings show a need for better targeted and tailored interventions for student depression and anxiety. Comorbid depression and anxiety is present in a non-clinical student and a sub-clinical population. Assessing the core symptoms of comorbid depression and anxiety in individuals refines the treatment of a comorbid diagnosis and helps predict the subsequent onset of the full-blown disorder in subclinical individuals. The findings offer student mental health services the scientific evidence to create unique, short-term evidence-based interventions for depression and anxiety. Depression and anxiety symptoms have an adverse effect on social functioning even in a sub-clinical student population. This has implications for psychological intervention for students and poses a challenge for diagnosis effects, as well as policies for mental health promotion at the institutional level. This study serves as empirical evidence for the need for education on mental health and provides a platform for a discussion on mental health problems and mental wellbeing among South African university students. It is possible that the severity and frequency of symptom endorsement was influenced by Covid-19 and the subsequent lockdown. It would therefore be helpful for future researchers to take this into consideration. This study was only conducted at one South African university which made the study limited in its generalisability to other universities. Future researchers should consider conducting the study in multiple South African universities. Other limitations included the use of an online survey platform to distribute the questionnaires as well as the study being a cross-sectional study
Substitution reactivity and structural variability induced by tryptamine on the biomimetic rhenium tricarbonyl complex
No full textA series of seven fac-[Re(CO)3(5Me-Sal-Trypt)(L)] complexes containing tryptamine on the N,O 5-methylsalicylidene
bidentate ligand backbone and where L is MeOH, Py, Imi, DMAP, PPh3 coordinated to the 6th
position have been studied, including the formation of a dinuclear Re2 cluster. The crystallographic solid
state structures show marked similarity in structural tendency, in particular the rigidity of the Re core and
the hydrogen bond interactions similar to those found in protein structures. The rates of formation and
stability of the complexes were evaluated by rapid time-resolved stopped-flow techniques and the
methanol substitution reaction indicates the significant activation induced by the use of the N,O
salicylidene bidentate ligand as manifested by the second-order rate constants for the entering
nucleophiles. Both linear and limiting kinetics were observed and a systematic evaluation of the kinetics
is reported clearly indicating an interchange type of intimate mechanism for the methanol substitution.
The anticancer activity of compounds 1–7 was tested on HeLa cells and it was found that all compounds
showed similar cytotoxicity where solubility allowed. IC50-values between ca. 11 and 22 mM indicate that
some cytotoxicity resides most likely on the salicylidene–tryptamine ligand. The photoluminescence of
the seven complexes is similar in maximum emission wavelength with little variation despite the broad
range of ligands coordinated to the 6th position on the metal centre.University of the Free StateSASOL Pty LtdSouth African National Research Foundation (SA-NRF)Publisher's versio
Integrating academic and career advising in a South African Higher Education institution
No full textSouth African Higher Education has focused extensively on widening access to further inclusivity and economic development. However, it has become apparent that access alone is not enough, as students need to persist and succeed in their studies to graduate in the minimum amount of time. International research on what contributes to timely degree completion has focused on academic advising, counselling, orientation programmes, learning communities, and institution-wide reform, amongst others. Academic advising stands out here, because research suggests that a comprehensive approach, specifically where effective academic advising is present and combined with other support efforts, best assists timely degree completion. This study thus delves deeper into effective academic advising practice. Academic advising, a well-known concept in the United States of America (USA), is relatively new field in South Africa. That said, there is a growing body of knowledge in South Africa on the impact of peers on students’ academic development and success. In addition to the challenge of timely degree completion, with the graduate unemployment rate of 11% and other challenges beyond the scope of this dissertation, higher education institutions’ responsibility to help students succeed should not end with assisting students in graduating. Rather, students need to be guided in career-related matters while engaging in curricular and co-curricular matters. As many as three out of four students entering the university for the first time have no clear career goals. The fact that there is little connection between academic majors and future career paths among general degrees can contribute to students making decisions incongruent with their academic and personal strengths. Therefore, it is crucial that academic and career information need to be integrated when advising students. Academic advisors are in an excellent position to facilitate guidance in career-related matters when providing academic advice. They are also well placed to assist students in developing academic goals and career plans consistent with their interests and values in order for them to succeed. This assistance in understanding how academic and personal interests, abilities, and values relate to possible careers and forming plans is what Gordon (2005) terms career advising. To explore how academic and career advising could be integrated in practice, this study uses the University of the Free State (UFS) as a case example. This study uses Gordon’s 3-I Process, a framework that integrates career advising into academic advising practice, as a lens to assess academic advising practice at the UFS. The 3-I Process is widely used within academia in the USA, and is associated with the National Academic Advising Association (NACADA) – the global leader in academic advising. This study is situated in the constructivist paradigm and follows a qualitative approach. Results from interviews with advisors at the UFS stress the need for such a unified framework, and recommendations are made on how advising at the UFS could develop more holistically. This study also contributes to the conceptualisation and practical application of advising in the broader South African context
Thuma Mina - an Isaiah 6:8 perspective in crossfire with Step-aside: SA ruling party’s moral restoration efforts
No full textThis article builds on the excellent article by Prof. Kgatle and Mashau who examined the prospects and success of the presidency of Cyril Ramaphosas by reflecting on the concept of Thuma Mina. In this article, Ramaphosa's Thuma Mina's manifesto is placed in the same restorative context as the implementation of the African National Congress (ANC) step-aid resolution. Almost 27 years of democracy today since the ANC came to power in South Africa in 1994, and yet it's members' moral values continue to decline, as reflected in Gwede Mantashe's devastating Organizational Diagnostic Report. This paper reflects upon the concept of Thuma Mina at Isaiah 6: 8 as redirected into politics by Cyril Ramaphosa to fight corruption in collaboration with the resolution of the 54th Conference. The Thuma Mina Group's implementation of Step-Aside threatened the unity of the ANC when the then suspended ANC General Secretary suspended his own suspension to suspend the ANC's President Cyril Ramaphosa. If the Magashule group succeeds in flaunting the party rules and rejecting the Step-Aside policy, this will lead to a political catastrophe. This paper uses two disciplines (theology and politics) to shed light on the prospects of Thuma Mina as advocated by President Cyril Ramaphosa, along with the fair implementation of the ANC's Step Aside resolution. This paper is important as it provides a more concise understanding of the concept of Thuma Mina within political campaigning.Publisher's versio
Perceptions and experiences of women in Benoni regarding weight loss strategies
No full textObesity is a worldwide disease reaching epidemic proportions and is characterised by abnormal or extreme fat accumulation, affecting all socio-economic groups in both advanced and developing countries irrespective of sex, culture, or age. More women compared to men are overweight in South Africa. With the high percentage of overweight and obesity in South Africa and given the social pressures on women in the media and among their peers to be thin (particularly in certain demographic areas), it might be expected that women would seek help from available weight-loss diets, programmes, strategies, and applications. In response, the weight-loss market has exploded. To date, very little is known regarding South African women’s opinions of and involvement with weight loss programmes and diets. Hence, a cross-sectional survey was conducted to evaluate: The perceptions and experiences of women 18 years and older on weight-loss strategies and how they were perceived by women residing in Benoni, a city close to Johannesburg, South Africa. An electronic self-reported survey, created with Evasys Software®, was shared via the local community newspaper and online social media platforms. Descriptive statistics were calculated, and associations were investigated by crosstabulation and using chi-square, Fisher's exact, and Wilcoxon rank tests as applicable. For the purpose of this study, programmes and different diets known to South African women were categorised and incorporated into the following seven categories: (i) commercial weight-loss diet plans; (ii) commercial weight-loss aids; (iii) commercial coaching methods; (iv) self-imposed dietary restrictions and adapted eating patterns; (v) diets prescribed by a health professional; (vi) diets prescribed by non-health professionals, and (vii) other, including mobile weight loss apps. A total of 272 participants completed the survey. Almost half of the participants fell in the age group between 40 to 60 years (48.2%), 71.7% held a tertiary qualification, 50.3% earned between R19 601.00-R38 200.00 per month, 75.8% were married or in a permanent relationship, and 88.2% were White. Most participants (71.7%) did not smoke, but smokers reported smoking and eating less when stressed. Most participants (76.9%) were overweight or obese, with low activity levels (52.6%), drank less than eight glasses of water per day (86.9%), and rated their health as good (71.2%). Participants reported having followed up to 10 diets in the last three years. A total of 619 diets, strategies, or applications were used across the different categories. The main motivation for following one of these was reported as weight loss. Across the different categories, self-imposed dietary restrictions/adapted eating patterns were used by the highest percentage (54.0%) of participants. Participants provided the following information for each reported strategy that they had followed: the reason(s) for discontinuing the diet plan, whether it was easy or hard to follow, and why it was too difficult, as well as challenges, level of frustration and hunger experienced while using the strategy. Among all the strategies followed, the highest percentage for objective obtained was reported for intermittent fasting. The highest percentage for no challenges experienced was reported for using a mobile weight-loss application, and the highest percentage of no frustration or hunger experienced, while using a strategy for an approach prescribed by a personal trainer. Only 31 out of the 619 strategies followed (chosen by 11.4% of participants) were prescribed by a healthcare professional, with half of these prescribed by dietitians. Dietitians need to position themselves as the preferred choice when spending money on weight loss. Future research needs to focus on exploring the reasons for the poor uptake of weight loss strategies by health professionals and dietitians compared to the other strategies. The insights provided by the current study regarding the weight loss strategies South African women choose and their experiences with these strategies may assist dietitians and other healthcare professionals to design and choose approaches that may lead to improved adherence to following a diet and long-term weight loss.University of the Free State Postgraduate Schoo
The association between serum procalcitonin levels and outcomes of patients admitted to two tertiary paediatric intensive care units in the Bloemfontein academic complex: a retrospective analytical study
No full textBackground: The risk of mortality should be assessed in all patients admitted to the Paediatric Intensive Care Unit (PICU). Procalcitonin (PCT) is a valuable biomarker in the diagnosis of sepsis in the PICU. Its use as a prognostic marker has been widely investigated with conflicting results. This study was done to assess the association between PCT and outcomes in the PICU in our setting thereby investigating its prognostic capabilities. Objectives: The primary objectives were to determine the admission PCT, the PCT between 48 – 72 hours of admission, and the PCT change within this time frame, of patients admitted to the PICU at two tertiary hospitals within the Bloemfontein academic complex as well as their primary (PICU mortality) and secondary (length of PICU stay, number of ventilatory days) outcomes. The secondary objectives were to compare these PCT trends with the primary and secondary outcomes. Methods: The study was a retrospective analytical cross-sectional medical record review of patients, between 1 to 60 months of age, who were admitted to the PICU within the Bloemfontein academic hospital complex from 01 January 2017 to 31 December 2018. Admission PCT and trends within 72 hours of admission were compared to the participant outcomes (PICU mortality, length of PICU stay and number of ventilator days). Data was obtained from the participants electronic and paper medical records and the National Health Laboratory Services database. De-identified data was submitted for analysis by the Department of Biostatistics, University of Free State. Results: 381 participants were included in the study. 55 participants died. 220 required mechanical ventilation. The median length of PICU stay was 6 days. Non-survivors had a higher median admission PCT (13.94ng/ml, IQR 1.0 – 100.0) than survivors (1.45ng/ml, IQR 0.36 – 13.08) (p<0.0001, 95% CI 1.28 – 15.12). Non-survivors had a higher median PCT at 48-72(12.79ng/ml, IQR 2.08 – 100.00) hours than survivors (1.31ng/ml, IQR 0.29 – 7.15) (p<0.0001, 95% CI 2.50 – 21.72). Non-survivors had less of a median decrease in PCT (-0.12ng/ml, IQR -3.68 to +4.125) than survivors (-0.40ng/ml, IQR -4.88 to +0.05) (p=0.22, 95% CI -0.59 - 4.72). The area under the receiver operating characteristics curve (AUROCC) for admission PCT to discriminate for mortality was 0.6702 and for the 48-72-hour PCT it was 0.7369. The strongest profile for PCT to discriminate for mortality was found at the 48-72hour PCT at a threshold of 3.16ng/ml (sensitivity 73.3%; specificity 64.5%). The median PCT change in participants requiring ventilation (-0.23ng/ml, IQR -2.72 to +0.52) was less than for those not requiring ventilation (-0.76ng/ml, IQR -6.34 to -0.05) (p= 0.0044, 95% CI -1.67 - -0.16). There was a positive correlation between PCT and number of ventilator days (spearman correlation co-efficient =0.1477, p=0.0138). There was no significant correlation between the length of PICU stay and admission PCT(p=0.7579), the PCT change (p=0.2034) or the percentage PCT change (p=0.2625). Conclusion: PCT displays some ability to discriminate for PICU mortality. Serial PCT measurements provide greater prognostic information. Non-survivors had a significantly greater median admission PCT, median PCT at 48-72 hours and a lower median PCT decrease than survivors. PCT above 3.16ng/ml at 48-72 hours had the strongest profile to discriminate for mortality
Ode to tragedies lost between land and sea
No full textThe ocean, a vast and mysterious force, sets the stage for tragic shipwreck events around the Southern Tip of Africa. Nearly 3 000 historical shipwrecks of different nationalities met their untimely demise at the hands of the ocean (SAHRA, 2020: online). Some are rooted in the depths of the ocean while remnants of others still protrude the surface of the sea clinging to the land awaiting their end. Meisho Maru no.38 fishing trawler, em-placed in the scene of the Southernmost Tip of Africa, is an icon in the larger shipwreck narrative caught between land and sea. Time has taken a toll on this icon with each year the memory rusts and fades away, as the ocean finishes what he started on 16 November 1982 (Atlasobscura, 2021: online). A Shipwreck Interpretation Centre, located next to Meisho Maru no.38 and Agulhas National Park, is proposed to preserve and recount forgotten shipwreck tragedies. The strong film quality of the setting inspires an intervention that builds on the experiential cinematic elements, creating architecture that tells a story. The Shipwreck Interpretation Centre, funded by SAN Parks, proposes sequences of architectural mises-en-scène which articulates both the dualities between and interconnectedness within human experiences as visitors move through places and times
A comparison of selected assessment results before and during the COVID-19 pandemic in one university in South Africa
No full textThe study examined the impact of coursework-only assessment, as made necessary at the onset of the COVID-19 pandemic, adopting a quantitative research approach with 1013 students. The data obtained were analysed using SPSS version 27.0 to obtain descriptive and inferential statistics. The results revealed significant differences between the 2019- and 2020 marks for the same courses. In two of the science courses (T2 and T3), the mean scores for 2019 were significantly higher than the mean scores for 2020. In the mathematics course, the 2020 marks were significantly higher than the marks for 2019. While a normal distribution was assumed for the science courses, the mathematic course showed marks that were skewed to the right. A higher number of distinctions in the F1 course and a significant decline in the mean scores for T1 and T2 implies that there is a need for professional development of lecturers teaching in the online space. It is, therefore, recommended that higher education lecturers need adequate professional development on setting and administering online assessments. The assessment should test adequate lower- and higher-order cognitive skills for sufficient testing of student knowledge during online assessments. Furthermore, a variety of assessment methods and a diversity of tasks may be used to ensure the reliability of the assessment outcomes.Publisher's versio