Abstract: The paper presents the statistical analysis on the compressive strength of concrete with strength ranging from 30 MPa to 130 MPa. To obtain these concrete strengths, concrete mixes with virgin aggregates were prepared with four different wate r to cementitious content (w/c) ratios i.e., 0.45, 0.36, 0.24, and 0.18. With w/c ratio of 0.45, a mix is also designed using recycled construction and demolition coarse aggregate to compare statistical characteristics with respect to concrete made using virgin aggregates. The presented statistical analysis includes measure of central tendency, dispersion of the data, distribution shape properties, and precision of the mean. A normal and a log-normal distribution has been established and validated for the experimental data set of all the mixes. A correlation has also been established for the compressive strength of 100mm cube and 150mm cube. Analysis shows an increase in dispersion of data with increase in the mean compressive strength of the mix. The mix with Construction and demolition waste aggregate shows a higher standard deviation than the mix with virgin aggregates at the same w/c ratio. The correlation curve for the compressive strength of 100 mm and 150 mm size cubes, shows a conversion factor of 1.04, suggesting an insignificant difference of the compressive strength values of 100 mm and 150 mm cubes for the mix studied.

Resumen: En este estudio se presenta un análisis estadístico de las resistencias a la compresión del hormigón, con resistencias que varían desde los 30MPa a los 130 MPa. Para obtener dichas resistencias, se prepararon mezclas de hormigón con áridos vírgenes para las siguientes cuatro diferentes razones agua-cemento (a/c): 0,45, 0,36, 0,24 y 0,18. Así, por ejemplo, para una razón a/c de 0,45, también se diseñó una mezcla usando áridos gruesos reciclados de construcción y demolición a fin de comparar las características estadísticas con las del hormigón preparado con áridos vírgenes. El análisis estadístico incluye la medida de tendencia central, dispersión de los datos, propiedades de la forma de distribución y precisión de la media. Se estableció y validó una distribución normal y log-normal para el conjunto de datos experimentales de todas las mezclas. También se estableció una correlación para la resistencia a la compresión los cubos de 100 mm y 150 mm. El análisis muestra un aumento en la dispersión de los datos al aumentar la resistencia a la compresión media de la mezcla. La mezcla con árido de residuos de construcción y demolición presenta una desviación estándar mayor que la mezcla con áridos vírgenes a la misma relación a/c. La curva de correlación para la resistencia a la compresión de los cubos de 100 mm y 150 mm muestra un factor de conversión de 1,04, sugiriendo una diferencia insignificante de los valores de resistencia a la compresión de los cubos de 100 mm y 150 mm para la mezcla estudiada.

INTRODUCTION: It is estimated that there are about 10% of cases that involve oral mucosa in patients with dengue hemorrhagic fever (HF), and even less number of cases in dengue fever (DF) has been reported. This leads to a lack of future investigation AIMS AND OBJECTIVES: This review intends to enhance the understanding of the epidemiology, clinical features involving the oral manifestations, and treatment of dengue disease. DESIGN AND METHODS: Several search engines, including PubMed, World Health Organization (WHO), and Pan American Health Organization (PAHO) websites were utilized for the literature search using the terms dengue and dengue shock syndrome. RESULTS: Dengue is a major arthropod-borne viral disease of humans. Its presentation is protean and varies from an undifferentiated viral syndrome to viral HF and severe shock. The early diagnosis of the oral manifestations, hemorrhagic, or mucocutaneous, may lead to timely clinical evaluation of the patient with signs and symptoms suggestive of dengue viral infection. CONCLUSION: The specific therapy for dengue infections is still undiscovered. Proper care, including vector control and prevention of mosquito bites, may be beneficial. However, the role of dental professionals and general practitioners is important in identifying the oral manifestations of dengue viral infection and providing specific diagnosis and effective treatment to the patients.

ABSTRACT Objective: To determine whether or not Jamaican coaches’ knowledge and practices of fluid replacement are on par with that of the National Athletic Association's and the American College of Sports Medicine Standards. Methods: A descriptive survey of 90 high-school track and field coaches in Jamaica was conducted. Coaches were given a 29-item survey questionnaire which adapted the content from previous surveys and also based on the National Athletic Trainers’ Association guidelines for fluid replacement and information sources of fluid replacement. A pass score of 80% was employed. Results: Approximately 26.6% of participants passed the knowledge-based assessment with the minimum requirement of 80% and 73.4% of participants had an unacceptable level of knowledge about fluid replacement and hydration. Only 26 (28.9%) coaches received training in fluid replacement therapy. Most of them therefore relied on reading materials ranging from magazines to journals, or learnt it on the job from other coaches. Conclusion: Findings suggest that the level of knowledge in Jamaican track and field high-school coaches about fluid replacement and hydration is very poor. However, their attitudes towards fluid replacement and hydration are very good, and this will facilitate their acceptance and adoption of correct fluid replacement guidelines. Tapping into this positive attitude and implementing workshops, seminars and onsite promotion should improve the coaches’ knowledge significantly.

This article considers the Australian case of Burrows v Houda 2020 NSWDC 485 and the English case of Lord McAlpine v Bercow 2013 EWHC 1342 (QB). Both cases considered the question of whether emojis could be considered to be defamatory and answered the question in the affirmative. This article also explores whether the South African courts will follow the lead of the Australian and English courts and concludes that emojis also have the potential to be considered defamatory in our law.

The SARS-CoV-2 pandemic has presented clinicians with an enormous challenge in managing a respiratory virus that is not only capable of causing severe pneumonia and acute respiratory distress syndrome, but also multisystem disease. The extraordinary pace of clinical research, and particularly the surge in adaptive trials of new and repurposed treatments, have provided rapid answers to questions of whether such treatments work, and has resulted in corticosteroids taking centre stage in the management of hospitalised patients requiring oxygen support. Some treatment modalities, such as the role of anticoagulation to prevent and treat potential thromboembolic complications, remain controversial, as does the use of high-level oxygen support, outside of an intensive care unit setting. In this paper, we describe the clinical management of COVID-19 patients admitted to Groote Schuur Hospital, a major tertiary level hospital at the epicentre of South Africa's SARS-CoV-2 epidemic during its first 4 months.

The SARS-CoV-2 pandemic has challenged the provision of healthcare in ways that are unprecedented in our lifetime. Planning for the sheer numbers expected during the surge has required public hospitals to de-escalate all non-essential clinical services to focus on COVID-19. Western Cape Province was the initial epicentre of the COVID-19 epidemic in South Africa (SA), and the Cape Town metro was its hardest-hit geographical region. We describe how we constructed our COVID-19 hospital-wide clinical service at Groote Schuur Hospital, the University of Cape Town's tertiary-level teaching hospital. By describing the barriers and enablers, we hope to provide guidance rather than a blueprint for hospitals elsewhere in SA and in low-resource countries that face similar challenges now or during subsequent waves.

It is an internationally accepted principle that ethics norms should be applied and enforced in research with humans through ethics review by research ethics committees (RECs). This places RECs at the very heart of the system for protecting participants and enforcing their rights. In the South African ethical-legal framework for child research, there are divergent approaches to consent. That is, section 71 of the National Health Act (No. 61 of 2003) (NHA) requires mandatory parental consent for child research, and limits the authority for proxy consent to parents and legal guardians. However, national ethics guidelines authorised by section 72 of the NHA and issued by the National Health Research Ethics Council (NHREC) acting in terms of its mandate (National Department of Health, 2015) allow a more nuanced approach - i.e. self-consent by older adolescents, provided certain conditions are met, and consent by a range of parental substitutes where there are no available parents or legal guardians. We have argued elsewhere that the consent approach in section 71 is inappropriately restrictive and are of the view that the consent approach endorsed in national ethics guidelines is more defensible. An REC that elects to approve a consent strategy allowable in ethics guidelines is effectively electing to not follow section 71, which raises the question of what the consequences might be for that REC. This article examines the legal liability of RECs through three 'threads' of accountability: the NHREC, the institutions hosting RECs, and the courts. We conclude that: (i) if an REC approves a child protocol with consent strategies allowable in terms of national ethics guidelines but not in terms of section 71, it is unlikely that the NHREC would discipline the REC in the face of a complaint - provided the REC acted within national ethics guidelines issued by the NHREC in terms of the latter's section 72 mandate to set national norms and standards; (ii) if an REC approves a consent approach allowed for in ethics guidance, it is also unlikely that the host institution would discipline the REC in the face of a complaint - especially if the institution is aware of the REC's explicit decision to follow national ethics guidelines that are authorised by section 72 of the NHA; and (iii) an REC could only be sued by a participant in terms of the law of delict (and be liable for damages) if several demanding components are proven, such as that the harm suffered by the participant resulted directly from the REC's actions in approving a particular consent strategy for that research. Furthermore, the court may well look to national ethics guidelines in making determinations about whether an REC's conduct was wrongful for the purposes of liability in civil law. RECs are protected from being collectively liable by insurance taken out by their host institutions. We make a series of recommendations to address this issue.

The need to obtain informed consent prior to any sterilisation is a very well-established ethical and legal obligation. South African law, however, does not specifically state who is responsible for obtaining informed consent before performing a sterilisation. This has implications for the liability of a surgeon or gynaecologist in circumstances where the informed consent is defective. Due to the vagueness of the applicable law, a surgeon or gynaecologist might be held liable, even in situations where he/she did not obtain the consent and relied on a nurse or assistant to procure the relevant informed consent. This article explores the relevant statutory law and canvasses two legal cases that came before the court regarding defective informed consent and the resultant liability for damages. We also make recommendations for proposed amendments to the current law to provide further clarity.

Resumo Nanopartículas (NPs) de TiO2 foram sintetizadas por métodos de sol-gel usando dois diferentes precursores, tetraisopropóxido de titânio e oxalato de potássio e titânio (KTO). Os precursores tiveram profunda influência nas propriedades estruturais, morfológicas, dielétricas e magnéticas das NPs de TiO2 sintetizadas, como evidenciado pelos estudos de DRX, FE-MEV, MET, LCR e VSM das amostras sintetizadas. As NPs de TiO2 derivadas de alcóxido apresentaram principalmente fases misturadas de anatásio e rutilo, enquanto que as NPs de TiO2 derivadas de KTO apresentaram fases anatásio e de Magnéli (TinO2n-1). Após tratamento térmico a 550 °C, o tamanho de cristalito das NPs derivadas de KTO foi menor do que o das NPs de TiO2 derivadas de alcóxido. As nanopartículas sintetizadas foram esféricas e aglomeradas com fases anatásio e rutilo em diferentes proporções na microestrutura da amostra de alcóxido. A constante dielétrica das NPs derivadas de KTO foi maior do que a das NPs derivadas de alcóxido. O comportamento diamagnético das NPs derivadas de KTO também foi maior do que o das NPs de TiO2 derivadas de alcóxido.

Abstract TiO2 nanoparticles (NPs) were synthesized by sol-gel methods using two different precursors, titanium tetraisopropoxide and potassium titanium oxalate (KTO). The precursors had a profound influence on the structural, morphological, dielectric and magnetic properties of synthesized TiO2 NPs, as evidenced by the XRD, FE-SEM, TEM, LCR and VSM studies in the synthesized samples. Alkoxide-derived TiO2 NPs contained mostly mixed phases of anatase and rutile, whereas KTO-derived TiO2 NPs contained anatase and Magnéli phases (TinO2n-1). After heat treatment at 550 °C, the crystallite size of KTO-derived NPs was lower than alkoxide-derived TiO2 NPs. The synthesized nanoparticles were spherical and agglomerated having anatase and rutile phases with different proportions in the microstructure of the alkoxide sample. Dielectric constant of the KTO-derived NPs was higher than the alkoxide-derived NPs. Diamagnetic behavior of KTO-derived NPs was also higher than the alkoxide-derived TiO2 NPs.

Sediment contamination may occur from various anthropogenic activities, such as mining-, agricultural- and industrial practices. Many of the contaminants arising from these activities enter the aquatic system and precipitate from the surrounding water, becoming bound to sediment particles. These bound contaminants may reach concentrations higher than in the overlying water. Although water quality may be acceptable, an aquatic system may still be at risk if the contaminated sediment were to be disturbed through flooding, bioturbation or changes in the water chemistry. These contaminants may then desorb into the water column and prove detrimental to life forms in contact and dependent on that water source. Sediment quality monitoring has been a widespread international initiative and has led to the development of sediment toxicity assessment methods. This study focused on sediment bioassays, namely, Phytotoxkit, Ostracodtoxkit F and the Diptera bioassay, in assessing sediment quality of the Tweelopiespruit-Rietspruit-Bloubankspruit river system in Gauteng, South Africa. This river is known to have been impacted by acid mine drainage (AMD) since late August, 2002. Exposure of river sediment from 7 sampling sites to these bioassays provided an eco-toxicological estimation of the acute toxicity and chronic toxicity emanating from the contaminated sediments. Physico-chemical analyses revealed higher levels of sediment contamination closer to the mine. The bioassays displayed a similar trend with greater sensitivities to sediments closer to the mine and lower sensitivities to the less contaminated sites further downstream. AMD was therefore the main driver for sediment contamination. Whilst not all contaminants were bioavailable, statistical analysis showed that there were significant correlations between the elevated contaminant concentrations closer to the mine and bioassay responses.

Bioassays, consisting of a diverse selection of organisms, aid in assessing the ecotoxicological status of aquatic ecosystems. Daphnia pulex and Hydra vulgaris are commonly used test organisms belonging to different trophic levels. The current study focused on comparing the sensitivity of H. vulgaris to D. pulex when exposed to geometric dilutions of two different water sources, the first (Site 1) from a source containing agricultural run-off and the second (Site 2), acid mine drainage. These sources were selected based on the contribution that the agricultural and mining sectors make to water pollution in South Africa. The bioassay method followed in this study was a modified version of the method described by the USEPA and additional peer-reviewed methods. The mortalities as well as morphological changes (H. vulgaris) were analysed using Microsoft Excel. The LC50-values were statistically determined using the EPA Probit Analysis Model and the Spearman-Karber analysis methods. Prior to being used, analysis of the physico-chemical properties, nutrients and metals of both water samples was performed. These results showed a relationship to the results obtained from the D. pulex and H. vulgaris bioassays, as Site 1 (lower concentration of contaminants) was less hazardous to both test organisms than Site 2 (higher concentration of contaminants). Both organisms can be used for ecotoxicity testing, with D. pulex being a more sensitive indicator of toxicity with regards to water sampled from the acid mine drainage site. Due to the sensitivities of sub-lethal endpoints observed over time, H. vulgaris may be used for chronic toxicity testing and D. pulex for acute toxicity testing.

ABSTRACT Objectives: This review sought to determine the epidemiology of diving injuries in Barbados and outcomes of treatment. Methods: This retrospective study is a review of medical notes from January 1995 to December 2009, from the hyperbaric chamber at the Barbados Defense Force. Data included age at time of injury, gender, nationality, residence and diving a ccident. Injury-specific data included time from onset of injury to treatment, presenting signs and symptoms and dia gnosis. The number of treatments performed and their outcomes were also noted. Results: During this period, 183 cases presented to the hyperbaric unit. Males accounted for 82% of the cases. The average age was 36.25 years (range: 17–79 years). Half lived in the Caribbean and dived mainly for work. Sport diving was responsible for 51.4% of the cases presenting to the unit. Decompression sickness Type 2 comprised 56% of the ca ses. Neurological symptoms were common, with numbness, weakness and strange sensations affecting 45.4, 43.7 and 47.5%, respectively. There was a mean of 3.35 treatments and 63.9% showed complete resolution of symptoms, and a further 25% showed improvement after treatment. Conclusion: Diving is a relatively safe activity but decompression illness does occur at times. The number of cases presenting to the unit decreased over the 15-year period for various reasons. However, the unit continues to have very good outcomes for those treated.

RESUMEN Objetivos: Esta revisión tuvo por objeto determinar la epidemiología de las lesiones de buceo en Barbados y los resultados del tratamiento. Métodos: Este estudio retrospectivo es una revisión de notas médicas desde enero de 1995 a diciembre de 2009, de la cámara hiperbárica de las Fuerza de Defensa de Barbados. Los datos incluyeron: edad en el momento de la lesión, género, nacionalidad, residencia, y accidentes de buceo. Los datos específicos de lesiones incluyeron el tiempo de ocurrencia de la lesión hasta el l tratamiento, los signos y síntomas presentados, y el diagnóstico. También se observaron el número de tratamientos realizados y sus resultados Resultados: Durante este período, se presentaron 183 casos a la unidad hiperbárica. Los hombres representaron el 82% de los casos. La edad promedio fue 36.25 años (rango: 17-79 años). La mitad vivían en el Caribe y buceaban principalmente para el trabajo. El buceo deportivo representó el 51.4% de los casos que acudieron a la unidad. La enfermedad de descompresión tipo 2 comprendió el 56% de los casos. Los síntomas neurológicos fueron comunes, a los que se sumaban entumecimiento, debilidad y sensaciones extrañas que afectaron al 45.4, 43.7 y 47.5%, respectivamente. Hubo una media de 3.35 tratamientos. El 63.9% mostró completa resolución de los síntomas y otro 25% mostró mejoría después del tratamiento. Conclusión: El buceo es una actividad relativamente segura, pero la enfermedad de descompresión ocurre a veces. El número de casos que se presentan a la unidad disminuyó por diversos motivos en un período de 15 años. La unidad continúa obteniendo muy buenos resultados con todos los que se someten a tratamiento.

ABSTRACT Epigallocatechin-3-gallate (EGCG) is a major ingredient present in green tea, which has a high antioxidant activity. In this study, the effect of EGCG was investigated on paraquat-induced haemolysis of erythrocyte membrane. Erythrocytes were incubated in 0.03, 0.3, 3.0 and 30 mg/mL EGCG, respectively and exposed to 30 mg/mL of paraquat for 10 minutes. The effect of paraquat was determined by an analysis of the osmotic fragility of the erythrocytes. The results showed that EGCG (30 mg/mL) significantly (p < 0.05) reduced the haemolysis of erythrocytes exposed to paraquat (5.0 mg/mL). This suggests that EGCG may have a protective effect on paraquat-induced erythrocyte membrane haemolysis and that consumption of green tea, with high EGCG concentration, could ameliorate the deleterious effect of paraquat toxicity on the haemolysis of erythrocyte membrane.

RESUMEN La Epigalocatequina-3-galata (EGCG) es uno de los ingredientes principales del té verde, que tiene una elevada actividad antioxidante. En este estudio se investigó el efecto de EGCG en la hemolisis de la membrana del eritrocito inducida por paraquat. Los eritrocitos fueron incubados en 0.03, 0.3, 3.0, y 30 mg/mL de EGCG respectivamente, y expuestos a 30 mg/mL de paraquat durante 10 minutos. El efecto del paraquat fue determinado mediante análisis de la fragilidad osmótica de los eritrocitos. Los resultados mostraron que la EGCG (30 mg/mL) redujo significativamente (p < 0.05) la hemolisis de los eritrocitos expuestos al paraquat (5.0 mg/mL). Esto sugiere que EGCG puede tener un efecto protector sobre la hemólisis de la membrana del eritrocito inducida por paraquat, y que el consumo de té verde, con alta concentración de EGCG, podría mejorar el efecto deletéreo de la toxicidad del paraquat sobre la hemolisis de la membrana del eritrocito.

ABSTRACT The Momordica charantia (MC) fruit has been documented to possess antidiabetic properties. However, these studies were not without controversy surrounding the blood glucose-lowering ability and the mechanism of action in diabetes therapy. In an effort to evaluate such claims in the Jamaican MC species known as cerasee, aqueous extracts of the unripe fruit were studied in normal and diabetic rats. Normal male Sprague-Dawley rats were divided into groups (n = 6) orally administered distilled water, 10% dimethyl sulfoxide (DMSO) solution, the aqueous extract (400 mg/kg body weight) and glibenclamide (15 mg/kg body weight), respectively prior to assessment of fasting blood glucose (FBG) concentration. The oral glucose tolerance test (OGTT) was conducted in normoglycaemic rats orally administered distilled water, 10% DMSO solution, glibenclamide (15 mg/kg body weight) or aqueous extracts of the fruit (200 and 400 mg/kg body weight). Blood glucose concentration was also monitored in streptozotocin-induced diabetic rats administered the aqueous extract (250 mg/kg body weight) or water vehicle after an overnight fast. The aqueous extracts showed no hypoglycaemic or antidiabetic activity. However, the administration of the aqueous extracts (200 and 400 mg/kg body weight) resulted in significant improvement in glucose tolerance of glucose-primed normoglycaemic rats during the OGTT. These data suggest that the glucose-lowering mechanism of the Jamaican MC fruit species likely involves altered glucose absorption across the gastrointestinal tract.

RESUMEN Estudios realizados han documentado que la fruta de la Momordica charantia (MC) posee propiedades antidiabéticas. Sin embargo, las afirmaciones de estos estudios en torno a la capacidad de esta planta para reducir la glucosa sanguínea y a su mecanismo de acción en el tratamiento de la diabetes, no han estado libres de controversia. En un esfuerzo por evaluar dichas afirmaciones sobre la especie de MC jamaicana, conocida como cundeamor, se estudiaron extractos acuosos de la fruta aún verde en ratas normales y diabéticas. Las ratas Sprague-Dawley machos normales se dividieron en grupos (n = 6) que recibieron por vía oral agua destilada, solución de dimetilsulfóxido (DMSO) al 10%, extracto acuoso (400 mg/kg de peso corporal), y glibenclamida (15 mg/kg de peso corporal) respectivamente, antes de evaluar la concentración de glucosa en sangre en ayunas (GSA). Se realizó la prueba oral de tolerancia a la glucosa (POTG) en ratas normoglicémicas por vía oral con agua destilada, solución de DMSO al 10%, glibenclamida (15 mg/kg de peso corporal) o extractos acuosos de la fruta (200 y 400 mg/kg de peso corporal). La concentración de glucosa en sangre también fue monitoreada en ratas con diabetes inducida mediante estreptozotocina a las que se les administró extracto acuoso (250 mg/kg de peso corporal) o vehículo de agua después de un ayuno nocturno. Los extractos acuosos no demostraron ninguna actividad antidiabética o hipoglicémica. Sin embargo, la administración de los extractos acuosos (200 y 400 mg/kg de peso corporal) resultó en una mejoría significativa de la tolerancia a la glucosa en las ratas normoglicémicas primadas con glucosa durante la POTG. Estos datos sugieren que el mecanismo reductor de la glucosa de la especie de fruta jamaicana MC probablemente implica la absorción alterada de glucosa en todo el tracto gastrointestinal.

BACKGROUND: The issue of what type of compensation a research participant would be entitled to in a clinical trial when they have signed an informed consent document excluding certain forms of compensation recently came before our courts in the matter of Venter v Roche Products (Pty) Limited and Others (Case No. 12285/08). In this case, the court had to consider whether the plaintiff, Mr Venter, was entitled to claim for non-medical costs such as pain and suffering, loss of income and general damages, even though the informed-consent document expressly excluded such claims. OBJECTIVES: To set out the facts, issues and judgment in the case, concluding with a discussion of the implications of the judgment for research ethics committees (RECs). METHODS: Critical review of a judgment of the Western Cape High Court. RESULTS: The court concluded that Mr Venter's application for damages should be dismissed because he had voluntarily agreed to the limited compensation as set out in the informed consent form that had been approved by both the local RECs and the Medicines Control Council. CONCLUSIONS: The Venter case has shown that delictual claims for research-related injuries will not be successful if plaintiffs have agreed to limit their own rights through signing an informed-consent form that limits compensation. This places an important obligation on RECs to ensure that they carefully review compensation clauses in informed-consent documents and that these are made clear to potential research participants.