Using a tree theme to develop language skills

A teaching prograrrrne is described in which trees are used as a unifying theme for developing language skills at the lower primary level

Monitoring the Effect of Micro-oxygenation before Malolactic Fermentation on South African Pinotage Red Wine with Different Colour and Phenolic Analyses

The use of micro-oxygenation and its effect on the quality of the red wine varietal, Pinotage, is largelyunknown. The influence of adding different oxygen dosages before malolactic fermentation on thephenolic composition and colour stabilisation of wine made from Pinotage was studied, and thesuitability of certain spectrophotometric and RP-HPLC analyses to determine these changes wereassessed in tanks of commercial lengths. Total oxygen dosages of 0 mg/L, 16 mg/L and 32 mg/L wereapplied, after which the wines underwent malolactic fermentation and maturation in the same tanks fortwo additional months. Decreases in anthocyanin concentration showed a strong inversely proportionalcorrelation with increasing polymeric pigment concentration. This suggests that the addition ofoxygen contributed to the early stabilisation of wine colour in Pinotage red wine. Overall, tanninconcentrations were not significantly influenced by the oxygen treatments, although lower levels wereobserved in wines treated with oxygen. An important finding of the study was that there appeared to belittle difference in the colour and phenolic composition of the wines between the 16 mg/L and 32 mg/Loxygen treatments. Good correlations were found between certain spectrophotometric techniques andthe RP-HPLC analysis used to study changes induced by micro-oxygenation (total anthocyanins, totalphenols). The colour and phenolic composition of Pinotage wine can be influenced before malolacticfermentation by micro-oxygenation. Some spectrophotometric phenolic analyses showed the sametendencies as observed with RP-HPLC (anthocyanins, monomeric flavan-3-ols, tannins), indicating theirsuitability to follow phenolic and colour changes induced by micro-oxygenation in Pinotage red wine

Continuous Synthesis of Gold Nanoparticles in Micro- and Milli-fluidic Systems

Gold nanomaterials have diverse applications ranging from healthcare and nanomedicine to analytical sciences and catalysis. Microfluidic and millifluidic reactors offer multiple advantages for their synthesis and manufacturing, including controlled or fast mixing, accurate reaction time control and excellent heat transfer. These advantages are demonstrated by reviewing gold nanoparticle synthesis strategies in flow devices. However, there are still challenges to be resolved, such as reactor fouling, particularly if robust manufacturing processes are to be developed to achieve the desired targets in terms of nanoparticle size, size distribution, surface properties, process throughput and robustness. Solutions to these challenges aremore effective through a coordinated approach from chemists, engineers and physicists, which has at its core a qualitative and quantitative understanding of the synthesis processes and reactor operation. This is important as nanoparticle synthesis is complex, encompassing multiple phenomena interacting with each other, often taking place at short timescales. The proposed methodology for the development of reactors and processes is generic and contains various interconnected considerations. It aims to be a starting point towards rigorous design procedures for the robust and reproducible continuous flow synthesis of gold nanoparticles

Kinetic simulations of X-B and O-X-B mode conversion

We have performed fully-kinetic simulations of X-B and O-X-B mode conversion in one and two dimensional setups using the PIC code EPOCH. We have recovered the linear dispersion relation for electron Bernstein waves by employing relatively low amplitude incoming waves. The setups presented here can be used to study non-linear regimes of X-B and O-X-B mode conversion.Comment: 4 pages, 3 figure

Investigation of Thiol Levels in Young Commercial South African Sauvignon Blanc and Chenin Blanc Wines Using Propiolate Derivatization and GC-MS/MS

In this work, the ethyl propiolate method for analysing thiols in white wine by GC-MS, originally proposed by Herbst-Johnstone et al.) (2013), has been adapted to GC-MS/MS and has been validated. The method performance has shown improvement in terms of sensitivity (limit of detection, LOD) and of the number of compounds measured. In addition to 3-mercaptohexanol (3MH), 3-mercaptohexyl acetate (3MHA), and 4-mercapto-4-methylpentan-2-one (4MMP), the adapted method can also measure 2-furanmethanethiol (FMT) and makes use of a commercially-available internal standard (IS), 4-methoxy-2-methyl-2-butanethiol (4M2M2B, IS). The proposed method was applied to determine thiol levels in young commercial South African Sauvignon and Chenin Blanc wines. The samples (n=20 for each cultivar) were chosen according to a high frequency of the typical descriptors associated with this class of impact compounds. 3MH was found at 178-904 ng/L and 99-1124 ng/L, and 3MHA at 23-151 ng/L and 5-253 ng/L in Sauvignon and Chenin Blanc respectively. 4MMP was present in Sauvignon Blanc in concentrations up to 21.9 ng/L, but in none of the Chenin Blanc samples

Highly reproducible, high-yield flow synthesis of gold nanoparticles based on a rational reactor design exploiting the reduction of passivated Au(III)

Reproducibility in the synthesis of nanomaterials is a crucial aspect for their real-life applications. It is particularly pertinent in the context of gold nanoparticles, where a plethora of seeded-growth methods are being developed to control particle morphology and size. The translation of such methods to manufacturing can be hindered by poor reproducibility of the seed production step. This study focuses on the development of a highly reproducible platform for the synthesis of gold nanoparticles, as potential substrates for glucose sensing. A flow reactor was designed, starting from a detailed study of the synthesis in batch. The well-established Turkevich synthesis was investigated via in situ time-resolved UV-vis spectroscopy. In order to enhance the reproducibility of the synthesis the effect of passivating the gold precursor stock before its use in the synthesis was investigated. It is shown that starting from a pre-passivated precursor provided improved control over the initial reaction stage, at the expense of a small increase in the reaction time. At the optimal reaction conditions, the proposed modified Turkevich method allowed for the synthesis in batch of ∼12 nm monodisperse (RSD ∼10%) particles, with a variability from batch to batch of only ∼5%. The information gathered from the batch study, in particular the reaction time, was used to translate the synthesis from batch to flow. The system utilized for the flow synthesis consisted of a segmented flow reactor, where an organic stream was employed to segment the reactive aqueous stream to avoid reactor fouling and improve monodispersity. The use of segmented flow enables treating each droplet as a “travelling batch”, hence allowing the direct use of the kinetic data obtained in batch to design the flow reactor, leading to the rapid identification of the minimum residence time to allow for reaction completion. The flow reactor enabled the synthesis of ∼11 nm monodisperse (RSD ∼10%) particles, with full precursor conversion and reproducibility between reactor runs higher than that obtained in batch (variability of ∼2%). The flow-produced gold nanoparticles were tested for glucose sensing, exploiting their glucose oxidase-mimicking behaviour and demonstrated satisfactory glucose detection in the range of 1–10 mM

Access to chloroquine in patients with rheumatic and musculoskeletal diseases attending rheumatology outpatient clinics during the COVID-19 pandemic

Herbal medicines made from the bark of the Cinchona tree, and later quinine, have been widely used for centuries to treat medical conditions such as tropical malaria. More recently, chloroquine (CQ) and its synthetic derivatives have been used as antimalarials and to treat systemic lupus erythematosus, rheumatoid arthritis, and in the past 14 months or so, COVID-19 pneumonia. Anecdotal evidence and the erratic covering through social media of its potential efficacy in the treatment of COVID-19 pneumonia have resulted in the widespread off-label use of CQ in South Africa and worldwide. This study aimed to show that access to CQ as a chronic medication for rheumatic and musculoskeletal diseases was limited during the COVID-19 pandemic, and that this resulted in an increased incidence of flares in these patients, affecting their morbidity and potentially leading to mortality

A phylogenetically distinct lineage of Pyrenopeziza brassicae associated with chlorotic leaf spot of Brassicaceae in North America

Light leaf spot, caused by the ascomycete Pyrenopeziza brassicae Sutton & Rawlinson, is an established disease of Brassicaceae in the United Kingdom (UK), continental Europe, and Oceania (OC, including New Zealand and Australia). The disease was reported in North America (NA) for the first time in 2014 on Brassica spp. in the Willamette Valley of western Oregon, followed by detection in Brassica juncea cover crops and on B. rapa weeds in northwestern Washington in 2016. Preliminary DNA sequence data and field observations suggest that isolates of the pathogen present in NA might be distinct from those in the UK, continental Europe, and OC. Comparisons of isolates from these regions genetically (multilocus sequence analysis, MAT gene sequences, and rep-PCR DNA fingerprinting), pathogenically (B. rapa inoculation studies), biologically (sexual compatibility), and morphologically (colony and conidial morphology) demonstrated two genetically distinct evolutionary lineages. Lineage 1 comprised isolates from the UK, continental Europe, and OC, and included the P. brassicae type specimen. Lineage 2 contained the NA isolates associated with recent disease outbreaks in the Pacific Northwest region of the USA. Symptoms caused by isolates of the two lineages on B. rapa and B. juncea differed, so ‘chlorotic leaf spot’ is proposed for the disease caused by lineage 2 isolates of P. brassicae. Isolates of the two lineages differed in genetic diversity as well as sensitivity to the fungicides carbendazim and prothioconazole

Neurologic outcome after penetrating extracranial arterial trauma

AbstractPurposeWe undertook this study to determine factors that adversely affect outcome in patients with penetrating injury to the extracranial cerebral vasculature.Patients and methodsMedical records were reviewed for all patients who had undergone surgical intervention to treat penetrating injury to the extracranial cerebral arteries between January 1989 and December 1999. Forensic autopsy findings were also reviewed for all patients who died as a result of their injury.ResultsOne hundred fifty-one patients with injury to the brachiocephalic artery (n = 21), common carotid artery (n = 98), or internal carotid artery (n = 32) were identified. Overall mortality was 21.2%, and stroke rate in surviving patients was 15.1%. Twenty-five of 32 deaths (78.1%) were stroke-related. Brachiocephalic artery injury was associated with the highest mortality (38.1%), and survivor stroke rate was highest in patients with internal carotid injuries (22.7%). Hemodynamic instability at presentation led to both higher mortality (30.7%) and stroke rate (19.2%). Preoperative angiography did not influence mortality or stroke rate in hemodynamically stable patients. Procedural mortality associated with arterial ligation was 45% (9 of 20 patients), and no surviving patient experienced a change in pre-ligation neurologic state. Nine patients remained neurologically intact after ligation, and 2 patients with preoperative localized neurologic deficit were unchanged postoperatively. In 131 patients, mortality after arterial repair was 17.6%, and in 5 surviving patients (5.4%) an ischemic neurologic deficit developed. Twelve of 15 surviving patients (80%) with preoperative neurologic deficit who underwent arterial repair had improved neurologic status. Cerebral infarcts were confirmed at autopsy in 23 patients; 18 infarcts were ischemic (10, repair; 8, ligation), and 5 infarcts were hemorrhagic (all, repair). No factor was identified that was predictive of ischemic versus hemorrhagic infarction in patients undergoing repair.ConclusionsThe presence of hypovolemic shock, internal carotid artery injury, complete vessel transection, and arterial ligation are associated with unfavorable outcome. Penetrating injury to the brachiocephalic, common carotid, or internal carotid artery should be repaired rather than ligated when technically possible. Subsequent ischemic or hemorrhagic cerebral infarction is unpredictable, but overall outcome is superior to that with ligation of the injured artery

A practical approach to managing diabetes in the perioperative period

Diabetes mellitus (DM) is a common multisystem disease with hyperglycaemia as the hallmark. It is a modifiable risk factor of complications after surgery. The incidence of DM and its impact on public health are steadily increasing globally. In South Africa (SA), it is estimated that a large proportion of people living with DM are undiagnosed. A number of international groups have addressed the problem of DM in the perioperative period, proposing guidelines for optimisation and management of these patients. The guidelines fail to address the variety of contexts within which surgery is delivered in SA. In this review, the authors discuss DM within the SA context. The article provides a range of approaches to managing the patient with DM in the perioperative period. Importantly, the perioperative healthcare provider’s approach should be steered by a local multidisciplinary team that considers the evidence base in light of their resource and patient context