Search

A localized solution-based iterative solver for method of moments (MoM) analysis of large antenna arrays with disjoint, nonidentical elements is presented. The formulation introduces computational cost reducing extensions for the direct coupling technique (DCT), which is a domain decomposition method (DDM) whereby element-associated overlapping local problems are iteratively solved. A residual-driven formulation improves convergence and enables matrix sparsification. Macro basis functions (MBFs) are incorporated, with convergence to user-specified error tolerance maintained. Through near-interaction preconditioning, local domain extensions are rendered implicit, removing the need for overlapping local solutions. A single-level, hybrid nested cross-approximation (NCA) acceleration scheme is employed. Rapid, controllable convergence is demonstrated for very large arrays. Faster runtimes than with the multilevel fast multipole method (MLFMM) in the commercial FEKO software suite, are demonstrated. Convergence rate is practically independent of excitation, including scattering analysis. The capability of preconditioner and local matrices being independent of excitation and iteration, enables efficient solution of multiple right-hand sides, e.g., for embedded element pattern (EEP) computations. The solver is well suited to parallelization.

Graph-based frames have been introduced as a logical framework which internalises an inherent boundary to knowability (referred to as ‘informational entropy’), due, e.g. to perceptual, evidential or linguistic limits. They also support the interpretation of lattice-based (modal) logics as hyper-constructive logics of evidential reasoning. Conceptually, the present paper proposes graph-based frames as a formal framework suitable for generalising Pawlak's rough set theory to a setting in which inherent limits to knowability exist and need to be considered. Technically, the present paper establishes systematic connections between the first-order correspondents of Sahlqvist modal reduction principles on Kripke frames, and on the more general relational environments of graph-based and polarity-based frames. This work is part of a research line aiming at: (a) comparing and inter-relating the various (first-order) conditions corresponding to a given (modal) axiom in different relational semantics; (b) recognising when first-order sentences in the frame-correspondence languages of different relational structures encode the same ‘modal content’; (c) meaningfully transferring relational properties across different semantic contexts. The present paper develops these results for the graph-based semantics, polarity-based semantics, and all Sahlqvist modal reduction principles. As an application, we study well known modal axioms in rough set theory (such as those corresponding to seriality, reflexivity, and transitivity) on graph-based frames and show that, although these axioms correspond to different first-order conditions on graph-based frames, their intuitive meaning is retained. This allows us to introduce the notion of hyperconstructivist approximation spaces as the subclass of graph-based frames defined by the first-order conditions corresponding to the same modal axioms defining classical generalised approximation spaces, and to transfer the properties and the intuitive understanding of different approximation spaces to the more general framework of graph-based frames. The approach presented in this paper provides a base for systematically comparing and connecting various formal frameworks in rough set theory, and for the transfer of insights across different frameworks.

A series of ferrocenyl- and ruthenocenyl-containing β-diketonato (triphenylphosphine)gold(I) complexes of the type [(RCO)(R′CO)-HαC-AuPPh3] were synthesized via the reaction of appropriate β-diketones, RCOCαH2COR′, with [(Ph3PAu)3][OBF4]. Complexes with R = R′ = CH3(1), or R = Fc = FeII(η5-C5H4)(η5-C5H5), and R′ = CF3(2), CH3(3), Ph = C6H5(4), or Fc (5), as well as R = RuII(η5-C5H4)(η5-C5H5) and R′ = CF3(6), CH3(7), Ph (8), Rc (9), or Fc (10), were obtained. The Au–αC bonding mode between gold and β-diketonato ligands was spectroscopically (NMR, FTIR, and XPS) identified as the only bonding mode for all complexes lacking a CF3moiety, while a mixture of Au–αC- and Au–(κO,κO)-bonded isomers in equilibrium with each other was observed for CF3-containing complexes 2and 6. This experimental observation is supported by a theoretical study utilizing density functional theory. Cyclic and square wave voltammetric studies in CH2Cl2/[N(nBu)4][B(C6F5)4] displayed only the metallocene-based redox processes of 2–10as reversible, well-resolved ferrocenyl and irreversible ruthenocenyl one-electron transfer steps. XPS spectra for each element in the complexes were measured, and an uncommon indirect proportionality between Au 4f7/2binding energies and the sum of R group electronegativities, ΣχR, as well as between the Fe 2p3/2binding energies and formal ferrocenyl reduction potentials, E°′, was obtained.

Ground-state and time-dependent density functional theory (TDDFT) calculations with the long-range-corrected, Coulomb-attenuating CAMY-B3LYP exchange-correlation functional and large, all-electron STO-TZ2P basis sets have been used to examine the potential “inverse hypercorrole” character of meso-p-nitrophenyl-appended dicyanidocobalt(III) corrole dianions. The effect is most dramatic for 5,15-bis(p-nitrophenyl) derivatives, where it manifests itself in intense NIR absorptions. The 10-aryl groups in these complexes play a modulatory role, as evinced by experimental UV–visible spectroscopic and electrochemical data for a series of 5,15-bis(p-nitrophenyl) dicyanidocobalt(III) corroles. TDDFT (CAMY-B3LYP) calculations ascribe these features clearly to a transition from the corrole’s a2u-like HOMO (retaining the D4hirrep used for metalloporphyrins) to a nitrophenyl-based LUMO. The outward nature of this transition contrasts with the usual phenyl-to-macrocycle direction of charge transfer transitions in many hyperporphyrins and hypercorroles; thus, the complexes studied are aptly described as inverse hypercorroles.

The need for low-cost and efficient biosorbent materials for the decontamination of heavy metal polluted water is important to abate the toxic effects on humans and the environment. Therefore, the present research reports the adsorption of cadmium ions from an aqueous solution onto alkaline-treated coconut shell (Alk-CCS) powder as a low-cost potential biosorbent. The biosorbent was characterized by SEM, XRD, FTIR, and EDX. Batch biosorption experiments were used to determine the effect of pH, time, temperature, dosage, and concentration on biosorption. The isotherm, kinetic, and thermodynamic modelling of the process was performed. The optimum condition for the adsorption of Cd2+onto Alk-CCS was a pH of 6.4, adsorbent dosage of 0.2 g, and a contact time of 30 min. Moreover, a maximum monolayer adsorption capacity of 14.22 mg/g was obtained from the Langmuir model for Cd2+adsorption. From the nonlinear isotherm and kinetics analysis, cadmium ions adsorption on Alk-CCS followed the pseudo-second-order model involving chemical interactions, while the Sips model best fitted the isotherm evaluation. According to the satisfactory fitting to the Sips isotherm model, the adsorption could not be best fitted to the classical adsorption isotherm models such as Langmuir and Freundlich. Thermodynamic parameters indicated that the adsorption of Cd ions on Alk-CCS was feasible, spontaneous (negative value of ∆G°), and exothermic (negative value of ∆H°). Moreover, the nonlinear modelling showed that alkaline modified coconut shell powder is a viable and efficient adsorbent for the removal of cadmium ions from polluted water.

Biochars are efficient materials for the adsorption of water pollutants. Moreover, the modification of biochars might enhance the adsorption potentials but increase the process cost. Therefore, the search for low-cost unmodified biochars with high adsorption capacity is needed. In this study, we prepared new biochar (PLBC) from low-cost Populus nigraleaves for oil sorption, in an attempt to search for unmodified biochar with high uptake capacity. The biochar was prepared by low-temperature pyrolysis at 350 °C in other to maintain a low process cost. The sorbent characterization revealed the presence of functional groups and surface pores on PLBC desirable for the sorption of oil. A decrease in the surface area of the biochar from 36.82 to 18.55 m2/g, the pore volume from 0.0372 to 0.0152 cm3/g, and the pore diameter from 4.434 to 3.276 nm was obtained after oil sorption. Elemental analysis of PLBC showed carbon content of 55.9% and a biochar yield of 58.6%. PLBC exhibited an oil uptake capacity of 4.634 g/g. The Freundlich and Pseudo-second-order models provided the best fit to the isotherm and kinetic evaluations, respectively, with the involvement of the intraparticle diffusion mechanism. Thermodynamics revealed a physicochemical, endothermic, feasible, and spontaneous oil uptake onto PLBC. High oil desorption (<92.5%) was achieved using petroleum ether as eluent, and PLBC exhibited good potentials for reuse. These investigations revealed the potential of PLBC as a viable low-cost sorbent for the treatment of oil spills.

In this study, published articles on the adsorptive removal of tartrazine from the aqueous phase were reviewed. Adsorbents sustaining both intercalating and photodegradation characteristics were also assessed. Besides collating available information on adsorbents employed for tartrazine removal, experimental conditions (solution temperature, pH, dosage, initial concentration, and agitation period) relating to the adsorptive removal of tartrazine were discussed. Deduction from kinetic, isotherms and thermodynamics data acquired from different adsorbents were assessed. Granular activated carbon and chitosan adsorbents had the least and highest tartrazine removal capacity. Lower solution pH majorly favoured the adsorption of tartrazine. On the other hand, increased dosage, contact time, initial concentration, and solution temperature generally enhanced the adsorptive uptake of tartrazine. Pseudo-second-order kinetics model was observed to typically describe the kinetic data. Freundlich and Langmuir isotherm models were popularly observed to best describe the tartrazine adsorption equilibrium. The uptake of tartrazine was generally spontaneous with the exception of a few nanocomposites. Meanwhile, π-π stacking, hydrogen bonding, Van der Waals forces and electrostatic interactions were proposed as possible mechanisms for the adsorption of tartrazine from wastewater. Adsorbents demonstrated good regeneration tendency with NaOH. Hence, it was concluded that the batch adsorption technique is economically viable and should be scaled up for industrial applications. Meanwhile, future work on tartrazine adsorption should employ real wastewater samples, regenerate adsorbents for reuse, design and execute a pilot scale assessment, employ column adsorption technique and formulate policy to regulate effluent discharge.

Bromophenol blue is a toxic triphenylmethane dye that is widely used in various industries. The dye-contaminated wastewater released from the industries results in substantial water pollution, causing several health problems and having severe negative consequences for the ecosystem. As a result, its toxic presence in environmental water is a cause for serious concern. Therefore, the removal of wastewater is vital to preserving environmental quality. The adsorption process stands out among several water treatment techniques due to its low cost, efficiency, simplicity, selectivity, and recyclability. Thus, several adsorbents have been applied for the treatment of bromophenol blue-contaminated water via the adsorption technique. This review presents the adsorption of bromophenol blue onto bio-based adsorbents such as biomass, activated carbon, and biochar as well as other potent materials like nanoparticles, polymers, and composite. The isotherm, kinetics, thermodynamics, and mechanism of the adsorption process were all discussed. We also considered the regeneration of the adsorbents and their reusability in the treatment process. Moreover, research gaps in many aspects were discovered, and future research proposals were offered.

The adsorption of pollutants onto metal and metal oxide nanoparticles of zinc oxide, silver, magnetite, and copper oxide as efficient adsorbents has received tremendous attention in recent years. However, only a few reports are available on the adsorption potentials of NiO nanoparticles (NiONPs). This work reports the adsorption of amoxicillin and nortriptyline pharmaceuticals onto biosynthesized NiONPs prepared from the aqueous leave extract of Platanus occidentalis. The plant leaf-mediated NiONPs were characterized via standard techniques and revealed successful synthesis of the nano-adsorbent. The NiONPs showed a pHpzc of 8.6, a surface area of 128.4 m2/g, pore volume of 0.486 cm3/g, and a pore diameter of 12.84 nm. The adsorption capacity of NiONPs for amoxicillin and nortriptyline was 116.7 mg/g and 72.62 mg/g, respectively. The Freundlich model was well suited to the isotherm modeling of the process compared to Temkin and Langmuir models. Kinetics was well described by the pseudo-second-order and intraparticle diffusion rate equations. The adsorption was found to be exothermic and spontaneous with a decrease in randomness at the pharmaceutical NiONPs interface. The biosynthesized NiONPs showed less than 10% decrease in the percentage adsorption of both pollutants after five cycles of reuse. This research showed that Platanus occidentalisleaf-mediated NiONPs is an efficient material for the adsorption of amoxicillin and nortriptyline.

Free-base corroles have long been known to be acidic, readily undergoing deprotonation by mild bases and in polar solvents. The conjugate base, however, has not been structurally characterized until now. Presented here is a first crystal structure of a free-base corrole anion, derived from tris(p-cyanophenyl)corrole, as the tetrabuylammonium salt. The low-temperature (100 K) structure reveals localized hydrogens on a pair of opposite pyrrole nitrogens. DFT calculations identify such a structure as the global minimum but also point to two cistautomers only 4–7 kcal/mol above the ground state. In terms of free energy, however, the cistautomers are above or essentially flush with the trans-to-cisbarrier so the cis tautomers are unlikely to exist or be observed as true intermediates. Thus, the hydrogen bond within each dipyrrin unit on either side of the molecular pseudo-C2axis through C10(i.e., between pyrrole rings A and B or between C and D) qualifies as or closely approaches a low-barrier hydrogen bond. Proton migration across the pseudo-C2axis entails much higher activation energies >20 kcal/mol, reflecting the relative rigidity of the molecule along the C1-C19pyrrole-pyrrole linkage.

Abstract: Metal oxide nanoparticles are prospective materials for wastewater treatment because of their natural abundance, low cost, and potent textural characteristics. Among metal oxide nanoparticles, manganese dioxide nanoparticles (MnO2NPs) are promising due to the associated structural flexibility, environmentally friendly nature, good stability, and high activity. However, there is a dearth of research on the use of MnO2NPs as adsorbents for water pollutants. In this work, MnO2NPs were synthesized by a green technique using the aqueous leaf extract of Populus nigrafor the adsorption of nortriptyline antidepressant and celestine blue dye. The FTIR, XRD, SEM, EDX, TGA, BET, and pHpzc characterizations revealed the successful synthesis of MnO2NPs, possessing potent surface characteristics. The maximum adsorption capacity of 33.94 mg/g and 60.31 mg/g was obtained for the adsorption of nortriptyline and celestine blue, respectively. Optimum adsorption conditions of pH 7.0, concentration 50 mg/L, and sonication time of 60 min for nortriptyline and 180 min for celestine blue were maintained. The isotherm, kinetic, and thermodynamic evaluation revealed the participation of various processes in the adsorption of the pollutants on MnO2NPs. Moreover, MnO2NPs were successfully regenerated with ethanol and reused for adsorption over five cycles. The findings proved that MnO2NPs are promising materials for the efficient decontamination of nortriptyline and celestine blue from wastewater, especially for the dye pollutant. Graphical Abstract:

ABSTRACTGiven the potential impact of climate change on amphibians, there is a need to establish baseline phenological data for vulnerable species and to investigate their responses to changing climatic conditions. We recorded vocalisations of Hewitt’s ghost frog Heleophryne hewittiin the Baviaanskloof World Heritage Site, South Africa, to investigate its breeding phenology and vocalisation behaviour. Our objectives were to: 1) characterise seasonal and diel vocalisation patterns, 2) examine relationships between environmental variables and calling behaviour and 3) evaluate the effectiveness of acoustic recording as a monitoring technique. We employed automatic vocalisation recognition software to detect calls and used hurdle regression to model the relationships between environmental variables and the number of calls produced. Our study confirmed that H. hewittiis a seasonal prolonged breeder, with reproductive activity occurring from early to late spring. We found that while relative humidity seemed to influence the probability of calling, none of the weather variables appeared to have a strong influence on the number of calls produced. Acoustic monitoring combined with automatic vocalisation recognition has proven to be a viable technique for monitoring this species. Further investigation of cues for breeding initiation is required to understand the impacts of climate change on this species.

Ipomoea batataspeel (IBP) is established as a viable lignocellulosic sorbent for wastewater treatment but has not been applied for the decontamination of oil-polluted water. This work reports for the first time the sorption of motor oil from water onto IBP as a natural eco-friendly sorbent. The FTIR spectra of IBP showed several functional groups desirable for efficient uptake of motor oil from water. SEM characterizations revealed an irregular and porous surface morphology, while EDX showed carbon (56.2%) and oxygen (39.0%) as major constituents of IBP sorbent. The BET surface area and pore characterizations of IBP revealed a surface of 5.774 m2/g, a pore volume of 0.00423 cm3/g, and an average pore diameter of 3.062 nm. The Langmuir model presented the best fit to the isotherm oil sorption analysis with a coefficient of determination (R2) of 0.9034 and a sum square error (SSE) of 0.0071. Kinetic modeling revealed that the process conformed to the intraparticle diffusion and pseudo-second-order model, while thermodynamics displayed a physical, endothermic, and feasible uptake of motor oil onto IBP. The oil sorption was found to be dominated by absorption mechanism and hydrophobic interactions. The motor oil-loaded IBP showed 96.2% oil desorption using petroleum ether as eluent. Besides, IBP exhibited efficient recycling and reuse for oil uptake with a decrease from 3.39 (initial uptake) to 2.82 g/g (fourth cycle). These investigations prove that IBP sorbent is a highly efficient biodegradable, eco-friendly, and reusable natural organic material for sequestration of motor oil from water.

In this research, the mechanism and efficiency of Cr(VI) uptake onto Irvingia gabonensisstem bark extract modified silica gel (IGMS) was reported for the first time. The pristine silica gel (PS) and IGMS adsorbents were characterized by the XRD, FTIR, FESEM, EDX, BET, and TGA techniques. The characterizations proved the successful coating of the plant extract onto silica gel. The FTIR spectra showed the Si–O–Si bands present on the silica gel materials. The FESEM revealed an increase in surface roughness of IGMS after coating with the plant extract, while TGA showed a high thermal stability of both PS and IGMS with over 65% of the initial weight retained at 800 °C. The batch Cr(VI) adsorption revealed optimum uptake at pH 2.0, with a maximum monolayer uptake capacity of 23.26–26.18 mg/g for IGMS at temperatures of 295 to 318 K. The kinetic modeling of Cr(VI) uptake onto PS and IGMS was best fitted by the Elovich model in comparison to the pseudo-second-order, pseudo-first-order, and intraparticle diffusion model. The Langmuir and Freundlich isotherms gave the best fit to the adsorption of Cr(VI) onto IGMS and PS, respectively. Adsorption thermodynamics revealed endothermic, increased randomness and spontaneous removal of Cr(VI) onto IGMS and PS adsorbents. The results revealed that Irvingia gabonensisstem bark extract modified silica gel is a viable and highly efficient adsorbent for the removal of Cr(VI) from Cr(VI)-contaminated effluents.

Despite the potent antimicrobial activity of magnetite nanoparticles (MtNPs), research on the antifungal activity of MtNP against filamentous fungi is rare. In this study, MtNP was synthesized by an inexpensive and easy green approach using the aqueous extract of Ananas comosus(pineapple) peels (AP), and applied as an antifungal agent against the filamentous fungal pathogens Fusarium verticilliodes, Aspergillus flavus, and Alternaria alternata(CGJM3078 and CGJM3006). The AP-mediated MtNP (AP-MtNP) was characterized by the XRD, UV-Visible, FTIR, BET, TGA, SEM, TEM, and EDX techniques. These characterizations revealed the successful synthesis of AP-MtNP by the reducing and stabilizing action of the aqueous extract of AP. The BET analysis showed a high surface area of 233.8 m2/g, while high thermal stability of AP-MtNP was displayed by the TGA. The SEM and TEM images mostly showed spherical AP-MtNPs with an average size of 17.87 nm and a somewhat dispersed and porous surface morphology. The newly synthesized AP-MtNPs exhibited effective antifungal activity against the four fungal strains.

In this research, a novel green tillite-based adsorbent (CMT) was synthesized by modifying the surface of natural/pristine tillite (PT) with Chrysophyllum albidumstem bark extract for the efficient removal of Cr(VI) from water. The physicochemical characteristics of PT and CMT were assessed by the use of the FTIR, XRD, BET, TGA, and SEM techniques. Cardinal adsorptive parameters such as solution pH, contact time, adsorbent dose, and initial concentration were used to optimize the efficiency of PT and CMT for Cr(VI) adsorption. The Elovich kinetic model was noticed to best describe the uptake of Cr(VI) onto PT and CMT. Hence, chemisorption was the rate-controlling step for Cr(VI) uptake onto both PT and CMT. Meanwhile, the Langmuir maximum adsorption capacity of PT and CMT was 51.06 and 291.8 mg g−1respectively, which was higher than those obtained for most materials used for Cr(VI) uptake. The Langmuir and Freundlich models best describe the equilibrium adsorption data for PT and CMT respectively. The reusability assessment of PT and CMT showed over 90% of the initial Cr(VI) uptake even after the fifth cycle of reuse. Electrostatic interaction and reduction of Cr(VI) were responsible for the removal of Cr(VI) from water onto the green material. The uptake of Cr(VI) was thermodynamically feasible, entropy-driven, and endothermic on both PT and CMT. The outcome of this study revealed that the anchoring of Chrysophyllum albidumstem bark extract on tillite produced a green adsorbent, which was highly efficient for the removal of Cr(VI) from polluted water.

Graphical Abstract:

The method of moments (MoM) is well suited to the electromagnetic analysis of antenna arrays, but solution cost grows rapidly with array size. This article concerns efficient MoM analysis of large antenna arrays with identical disjoint elements in arbitrary layouts. The domain Green’s function method (DGFM) is a domain decomposition method (DDM) for such arrays. Its unique benefit is that only local problems are solved to obtain an approximate global solution. Its main drawback is uncontrolled, problem-dependent solution errors. An improved scheme denoted iterative radius-based DGFM (IRB-DGFM) is formulated, in standard and residual-driven (RD) versions. Accuracy is improved by introducing local MoM domains, and solution error control is achieved via an iterative scheme, to obtain the true MoM solution to user-specified tolerance. Various computational cost reduction methods are proposed for the new formulations. Results show that the RD-IRB-DGFM is superior, yielding rapid convergence for diverse arrays. The methods are ideally suited to parallelization.

The present research work reports the preparation of Hyphaene thebaicaderived-biochar (HTBC) and its applicability as eco-friendly and low-cost adsorbent for the removal of methyl orange (MO) dye. The main physicochemical characteristics of HTBC including its morphology, crystallinity and chemical function groups were determined through scanning electron microscopy (SEM), energy dispersion spectroscopy (EDS), powder X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The results showed that HTBC adsorbent was found to be constituted by heterogeneous surface with mesoporous having a surface area of 33.38 m2/g and pore diameter of 23.53 nm, and carboxylic and amine functional groups. Adsorption experiments were conducted using batch mode, by varying key adsorption parameters such as contact time, solution pH, adsorbent dosage and concentration. Adsorption isotherm modelling revealed that the Langmuir model (higher R2and lower χ2) provided a better fit for MO adsorption onto HTBC, while the adsorption kinetics followed a pseudo-second-order kinetic model. Under optimized conditions (pH 2, HTBC dose of 0.03 g, initial dye concentration of 100 mg/L, 313 K, 270 rpm), the maximum Langmuir monolayer adsorption capacity for MO adsorption onto HTBC was found to be 264.922 mg/g. According the thermodynamic parameters, it can be deduced that MO adsorption on HTBC was exothermic and spontaneous. Adsorption mechanism can be attributed to various interactions, including electrostatic attraction, H-bonding, and π-π interaction. In light of these findings, biochar from Hyphaene thebaicashells can be considered a cost-effective and biodegradable adsorbent with significant potential for the treatment of water contaminated with anionic dyes.

The STREAM stage 1 trial showed that a 9-month regimen for the treatment of rifampicin-resistant tuberculosis was non-inferior to the 20-month 2011 WHO-recommended regimen. In STREAM stage 2, we aimed to compare two bedaquiline-containing regimens with the 9-month STREAM stage 1 regimen.

Background:Diabetes self-management education (DSME), a prerequisite for diabetes care, is mostly unstructured and inaccessible in the public health sector in South Africa (SA). Patient education is often delivered by healthcare professionals (HCPs) with limited time and proficiency, resulting in preventable errors with insulin administration. A study was undertaken to assess the knowledge of HCPs on the practical aspects of insulin administration and it was hypothesised that their expertise was insufficient. The unmet needs of DSME often transpire when preventable errors with insulin administration become clinically evident at higher levels of care.Methods:A prospective, descriptive study of HCPs’ knowledge before and after attending a ‘Diabetes 101’ workshop was performed. Four workshops at Tygerberg Hospital (TH) and Worcester Provincial Hospital (WPH) were assessed between 2016 and 2019. A total of 146 participants completed a questionnaire before and after the workshops. Knowledge was scored on the correct responses per question and overall. The mean pre- and post-test scores were compared using two sample t-tests. Chi-square tests were used to analyse differences between pre- and post-training responses.Results:Of 146 participants, the majority were medical doctors (n = 116; 80%), mostly junior (n = 75; 65%) with 21% nursing practitioners. Before training there were significant deficiencies identified with only 3 of the 19 question items answered correctly by more than 50% of HCPs. The greatest knowledge deficits were with regard to insulin re-suspension and the injection technique and priming of the insulin pen. Following training there was a significant improvement between the pre-test mean percentage score of 36.0% (15) and post-test mean percentage score of 68% (16) (p < 0.001).Conclusion:Knowledge on the practical aspects of insulin administration is insufficient amongst HCPs but improved after structured education. Further research is needed to assess the long-term retention of knowledge and the impact of knowledge translation into clinical care.

IMPORTANCE: There is epidemiologic evidence that the increasing incidence of thyroid cancer is associated with subclinical disease detection. Evidence for a true increase in thyroid cancer incidence has also been identified. However, a true increase in disease would likely be heralded by an increased incidence of thyroid-referable symptoms in patients presenting with disease. OBJECTIVES: To evaluate whether modes of detection (MODs) used to identify thyroid nodules for surgical removal have changed compared with historic data and to determine if MODs vary by geographic location. DESIGN, SETTING, AND PARTICIPANTS: This was a retrospective analysis of pathology and medical records of 1328 patients who underwent thyroid-directed surgery in 16 centers in 4 countries: 4 centers in Canada, 1 in Denmark, 1 in South Africa, and 12 in the US. The participants were the first 100 patients (or the largest number available) at each center who had thyroid surgery in 2019. The MOD of the thyroid finding that required surgery was classified using an updated version of a previously validated tool as endocrine condition, symptomatic thyroid, surveillance, or without thyroid-referable symptoms (asymptomatic). If asymptomatic, the MOD was further classified as clinician screening examination, patient-requested screening, radiologic serendipity, or diagnostic cascade. MAIN OUTCOMES AND MEASURES: The MOD of thyroid nodules that were surgically removed, by geographic variation; and the proportion and size of thyroid cancers discovered in patients without thyroid-referable symptoms compared with symptomatic detection. Data analyses were performed from April 2021 to February 2022. RESULTS: Of the 1328 patients (mean [SD] age, 52 [15] years; 993 [75%] women; race/ethnicity data were not collected) who underwent thyroid surgery that met inclusion criteria, 34% (448) of the surgeries were for patients with thyroid-related symptoms, 41% (542) for thyroid findings discovered without thyroid-referable symptoms, 14% (184) for endocrine conditions, and 12% (154) for nodules with original MOD unknown (under surveillance). Cancer was detected in 613 (46%) patients; of these, 30% (183 patients) were symptomatic and 51% (310 patients) had no thyroid-referable symptoms. The mean (SD) size of the cancers identified in the symptomatic group was 3.2 (2.1) cm (median [range] cm, 2.6 [0.2-10.5]; 95% CI, 2.91-3.52) and in the asymptomatic group, 2.1 (1.4) cm (median [range] cm, 1.7 [0.05-8.8]; 95% CI, 1.92-2.23). The MOD patterns were significantly different among all participating countries. CONCLUSIONS AND RELEVANCE: This retrospective analysis found that most thyroid cancers were discovered in patients who had no thyroid-referable symptoms; on average, these cancers were smaller than symptomatic thyroid cancers. Still, some asymptomatic cancers were large, consistent with historic data. The substantial difference in MOD patterns among the 4 countries suggests extensive variations in practice.

AbstractVolatility is one of the measures of risk within the financial markets. GARCH modelling involves important volatility forecasting methodology and is widely used in finance. It is important to be able to forecast volatility since volatility has an impact on financial portfolios and the risk hedging methodology followed by financial companies. This study investigates the behaviour of parameter estimates and volatility forecasts of GARCH models over time, using a rolling window estimation procedure. Three GARCH models, the Symmetric GARCH, GJR-GARCH and E-GARCH models, are compared. The dataset used in the study comprises of the JSE All-Share index. This index is divided into two different periods, namely, a tranquil financial period and a turbulent financial period. Different factors influence the performance of GARCH models and consequently determines which GARCH model is the most suited for certain circumstances. These factors are: the sample window period, forecasting horison, the financial period and the underlying distribution of the log returns.

At the inaugural Belhar Lecture (1) on 29 February 2012, Dr Wesley Granberg-Michaelson explored the ecumenical vision of unity articulated in the Belhar Confession, which emerged from the campus of [...]

Subacute thyroiditis is a granulomatous inflammatory disorder often triggered by a preceding viral infection. Patients typically present with complaints of anterior neck pain associated with a tender enlarged thyroid gland. The coronaviruses have never before been implicated in the aetiology of subacute thyroiditis. It is postulated that the pathogenesis related to thyroid disease in Coronavirus disease 2019 (COVID-19) is multifactorial. Contributory factors include effects of the virus-related cytokine storm and direct action of the virus on SARS-CoV-2 receptors in the thyroid. This article further reviews the association between thyroiditis and COVID-19. The clinical characteristics, diagnostic workup and management of a patient who presented with subacute thyroiditis following COVID-19 are discussed. Furthermore, complications are entertained and suggestions for the management of thyroiditis following COVID-19 are provided.

Abstract This article explores the relationship between the three aspects of the social agenda of the ecumenical movement captured in the motto of 'Justice, peace and care for creation'. It [...]

AbstractMSI2 is a homolog 2 of the Musashi RNA binding proteins (MSI) and is known to contribute to acute myeloid leukaemia (AML) and expressed up to 70% in AML patients. High expression of MSI2 has been found to lead to the lower overall survival of patients with AML. This study proposed the potential antagonists of MSI2 RNA-recognition motifs (MSI2 RRM1) derived from the LC-MS analysis of three traditional herbal samples. The LC-MS analysis of the three traditional herbs concoctions yields a total of 271 unique molecules of which 262 were screened against MSI2 RRM1 protein. After the dynamic study of the selected 8 top molecules from the virtual screening, the five most promising ligands emerged as potential MSI2 antagonists compare to the reference experimental molecule. The results show that the dynamic of MSI2 RRM1 protein is accompanied by a rare even of protein chain dissociation and re-association as evident in both the bound and unbound state of the protein. The unbound protein experience earlier chain dissociation compare to ligand-bound protein indicating that ligand binding to the protein slows down the dissociation time but thereafter increases the frequency of alternation between the protein chain association and dissociation after the first experience. Interestingly, the re-association of the protein chain is also accompanied by full restoration of the ligands to the binding site. The drug candidate Methotrexate (M3) and rescinnamine (M9) are listed among the promising antagonist of MSI2 with unique properties compared to a less promising molecule Ergotamine (M6).Communicated by Ramaswamy H. Sarma

The aim of the study was to investigate whether the content of Corporate Social Responsibility (CSR) messages predicts communication outcomes in South African nonprofit organisations (NPOs). The study found a positive association between CSR message content and CSR communication outcomes. Additionally, CSR message content in nonprofit organisations is positively linked to their CSR communication outcomes. Furthermore, support for community-related activities positively impacts CSR communication outcomes, thereby explaining the correlation between CSR message content and communication effectiveness. The study lays the groundwork for non-profit organisations seeking optimisation of their CSR messaging to achieve a wider socio-economic impact on the public at large. These results underscore the importance for nonprofit organisations to strategically develop CSR messages that highlight their support for community-related activities. By emphasising such content in their communication efforts, organisations can enhance their CSR communication outcomes, potentially fostering stronger relationships with stakeholders and garnering increased support for their initiatives.

Background:The association between hyperemesis gravidarum (HG) and abnormal thyroid function is well known.Aims:The prevalence, aetiology and course of thyrotoxicosis in women with hyperemesis gravidarum (HG) were studied.Methods:Women admitted for HG, who underwent thyroid function evaluation between 1 August 2016 and 30 April 2019, were studied. Laboratory data included baseline human chorionic gonadotropin (hCG) and baseline (t1), discharge (t2) and follow-up (t3) thyroid function tests (thyroid stimulating hormone [TSH] and free thyroxin [fT4]). Available TSH receptor antibody status was assessed.Results:Eighty-two patients were included. The incidence of thyrotoxicosis was 49% based on local laboratory TSH range and 48% if trimester-specific ranges used. In the majority of normal pregnancies, thyrotoxicosis was hCG-mediated (72.5%), 15% were confirmed to have Graves’ disease and 12% had a molar pregnancy. Very high fT4 levels (> 40 pmol/l) at baseline [t1] were documented in 24% of women with hCG-mediated thyrotoxicosis. Clinical features were absent in a third of women with Graves’ disease and the diagnosis was reliant on positive antibody status. Free T4 values declined from (t1) to later in gestation (t3) (p < 0.001).Conclusion:The incidence of thyrotoxicosis in women with HG is high. Free-T4 values decrease with clinical stabilisation of HG, suggesting a contribution of dehydration to the large variation in baseline fT4 measurements. Testing for TSH-receptor antibodies should be considered in women with TSH < 0.01 pmol/l and persistent fT4 elevation on follow-up. Final review of thyroid function should be performed after 15 weeks’ gestation.

Background:Increased bone resorption is a well-described consequence of primary hyperparathyroidism (PHPT). In South Africa, little is known about the impact of PHPT on skeletal health.Objective:To determine the prevalence of decreased bone mineral density (BMD), vertebral fractures and osteitis fibrosa cystica in patients with PHPT who underwent parathyroidectomy.Methods:Retrospective study of patients who underwent parathyroidectomy for PHPT at Tygerberg Hospital in Cape Town, from January 2010 to December 2019. Clinical, biochemical and BMD parameters are described.Results:Final analysis included 56 patients (median age 63.5 years; 80.4% female). Initial calcium, parathyroid hormone (PTH) and 25-hydroxyvitamin D (25[OH]D) levels were 2.93 mmol/l, 19.4 pmol/l and 34.0 nmol/l, respectively. Of the total cohort, 71.4% had decreased BMD. The prevalence of osteoporosis and osteopenia in postmenopausal women and men ≥ 50 years was 50.0% and 39.1% respectively; low bone mass for age in premenopausal women and men < 50 years was 20.0%. Vertebral fractures were seen in 21.2% of patients on radiography. Osteitis fibrosa cystica was present in five patients (9.6%). PTH levels were significantly elevated in patients with osteoporosis compared with those with normal BMD (36.4 vs. 16.1 pmol/l; p = 0.02).Conclusion:Two-thirds of patients who underwent parathyroidectomy for PHPT had decreased BMD, with osteoporosis present in 50% of postmenopausal women and older men. One in five had vertebral fractures. These findings underscore the importance of skeletal assessment in the management of PHPT.

Abstract This essay builds on the conference on 'Mission in the 21th century: New models and strategies in a world of diversity' held in Livingstone, Zambia from 25 March to [...]

Abstract Cut-to-length is not the harvesting system of choice in the southeastern United States although it is perceived by many to have the ability to recover more value from cut [...]

Background:Pre-existing diabetes mellitus (DM), hyperglycaemia and obesity emerged as prognostic factors in severe Coronavirus disease 2019 (COVID-19). To date, no published South African studies report on the incidence, presentation and outcomes of DM and diabetic ketoacidosis (DKA) during the COVID-19 pandemic.Objective:To reflect on the diagnosis, management, obstacles to care and outcome of four patients who were admitted to Tygerberg Hospital, Cape Town, South Africa. The outcome of these cases that presented consecutively with DKA and COVID-19 between May and July 2020 are discussed, the presentation, management and long-term considerations with specific reference to DKA and COVID-19 are reviewed.Results:Three of the four patients had newly diagnosed DM. These patients presented with non-specific symptoms and signs leading to a diagnosis of both DKA and COVID-19. The single surviving patient in this series was known to have pre-existing DM but discontinued his insulin upon becoming unwell. One patient required insulin therapy at the time of initial presentation a week or two prior to the current admission but received metformin instead. She was diagnosed with COVID-19 after having poor glycaemic control for over one week, after which insulin was initiated. Ultimately she died as a result of severe hypokalaemia. One patient primarily had respiratory complaints, severe COVID-19 pneumonia and received concomitant dexamethasone. Glycaemic control in this patient was complicated by both hypo- and hyperglycaemia.Conclusion:These cases highlight the management challenges faced by many developing countries, and identify the missed opportunities in persons presenting with COVID-19 and hyperglycaemic emergencies.

Metastasis of a neuroendocrine tumour (NET) to the orbit is a rare occurrence, with published data limited to a few case reports. Orbital involvement usually presents with proptosis and decreased ocular mobility. Timing, in relation to the presentation of the primary tumour (PT), varies. The authors report a case of a 58-year-old female whose clinical presentation of orbital metastases preceded clinical suspicion of a midgut NET. Her presentation was with severe headaches and bilateral ptosis, histologically proven to be due to orbital muscle infiltration. The PT location was determined from the histopathological markers on orbital muscle biopsy, which suggested a gastrointestinal origin. Abdominal computed tomography (CT) was in keeping with a midgut NET with features characteristic of a desmoplastic reaction. Additional CT findings were widespread metastases, corroborated by nuclear imaging. The patient developed carcinoid syndrome and subsequently underwent surgical resection of the PT due to acute bowel obstruction. Her carcinoid symptoms and ocular findings improved on continued somatostatin receptor analogue therapy, but she sadly died within one month following surgery.

New anti-tuberculosis regimens that are shorter, simpler, and less toxic than those that are currently available are needed as part of the global effort to address the tuberculosis epidemic. We aimed to investigate the bactericidal activity and safety profile of combinations of bedaquiline, pretomanid, moxifloxacin, and pyrazinamide in the first 8 weeks of treatment of pulmonary tuberculosis.