Methods for the separation of hydraulic retention time and solids retention time in the application of photosynthetic microorganisms in photobioreactors: a review.

Photosynthetic microorganisms have a wide range of biotechnical applications, through the application of their versatile metabolisms. However, their use in industry has been extremely limited to date, partially because of the additional complexities associated with their cultivation in comparison to other organisms. Strategies and developments in photobioreactors (PBRs) designed for their culture and applications are needed to drive the field forward. One particular area which bears examination is the use of strategies to separate solid- and hydraulic-residence times (SRT and HRT), to facilitate flow-through systems and continuous processing. The aim of this review is to discuss the various types of PBRs and methods which are currently demonstrated in the literature and industry, with a focus on the separation of HRT and SRT. The use of an efficient method of biomass retention in a PBR may be advantageous as it unlocks the option for continuous operation, which may improve efficiency, and improve economic feasibility of large-scale implementation of photosynthetic biocatalysts, especially where biomass is not the primary product. Due to the underexplored nature of the separation of HRT and SRT in reactors using photosynthetic microorganisms, limited literature is available regarding their performance, efficiencies, and potential issues. This review first introduces an overview into photosynthetic microorganisms cultivated and commonly exploited for use in biotechnological applications, with reference to bioreactor considerations specific to each organism. Following this, the existing technologies used for the separation of HRT and SRT in PBRs are explored. The respective advantages and disadvantages are discussed for each PBR design, which may inform an interested bioprocess engineer.

Child and adult spinal tuberculosis at tertiary hospitals in the Western Cape, South Africa: 4-year burden and trend.

The aim of this retrospective review was to assess the overall burden and trend in spinal tuberculosis (TB) at tertiary hospitals in the Western Cape Province of South Africa. All spinal TB cases seen at the province's three tertiary hospitals between 2012 and 2015 were identified and clinical records of each case assessed. Cases were subsequently classified as bacteriologically confirmed or clinically diagnosed and reported with accompanying clinical and demographic information. Odds ratios (OR) for severe spinal disease and corrective surgery in child vs. adult cases were calculated. A total of 393 cases were identified (319 adults, 74 children), of which 283 (72%) were bacteriologically confirmed. Adult cases decreased year-on-year (P = 0.04), however there was no clear trend in child cases. Kyphosis was present in 60/74 (81%) children and 243/315 (77%) adults with available imaging. Corrective spinal surgery was performed in 35/74 (47%) children and 80/319 (25%) adults (OR 2.7, 95% confidence interval 1.6-4.5, P = 0.0003). These findings suggest that Western Cape tertiary hospitals have experienced a substantial burden of spinal TB cases in recent years with a high proportion of severe presentation, particularly among children. Spinal TB remains a public health concern with increased vigilance required for earlier diagnosis, especially of child cases.

Long-term impacts of grazing intensity on soil carbon sequestration and selected soil properties in the arid Eastern Cape, South Africa.

BACKGROUND: Little is known about how basic soil properties respond to contrasting grazing intensities in the Karoo biome, South Africa. The aim of this study was to investigate impacts of long-term (>75 years) grazing at 1.18 heads ha(-1) (heavy; CGH), 0.78 heads ha(-1) (light; CGL), and exclosure on selected soil properties. Soil samples were collected to a depth of 60 cm from the long-term experimental site of Grootfontein Agricultural Development Institute, Eastern Cape. The samples were analyzed for C, N, bulk density and infiltration rate, among others. RESULTS: Generally, heavy and light grazing reduced soil N storage by 27.5% and 22.6%, respectively, compared with the exclosure. Animal exclusion improved water infiltration rate and C stocks significantly (P < 0.05), which was 0.128, 0.097, and 0.093 Mg ha(-1) yr(-1) for exclosure, CGL and CGH, respectively. Soil penetration resistance was higher for grazing treatments in the top 3-7 cm soil layer but for exclosure at the top 1 cm soil surface. CONCLUSION: Although livestock exclusion has the potential to improve C sequestration, a sufficient resting period for 1-2 years followed by three consecutive grazing years at light stocking rate would be ideal for sustainable livestock production in this arid region of South Africa.

Experience on postmortem minimally invasive tissue sampling to ascertain the cause of death determination in South African children: A case for implementing as standard of care.

Determining the death burden for prioritising public health interventions necessitates detailed data on the causal pathways to death. Postmortem minimally invasive tissue sampling (MITS), incorporating histology, molecular and microbial culture diagnostics, enhances cause-of-death attribution, particularly for infectious deaths. MITS proves a valid alternative to full diagnostic autopsies, especially in low- and middle-income countries. In Soweto, South Africa (SA), the Child Health and Mortality Prevention Surveillance (CHAMPS) programme has delineated over 1 000 child and stillbirth deaths since 2017. This SA CHAMPS site supports advocating for the use of postmortem MITS as routine practice, for more granular insights into under-5 mortality causes. This knowledge is crucial for SA's pursuit of Sustainable Development Goal 3.2, targeting reduced neonatal and under-5 mortality rates. This commentary explores the public health advantages and ethicolegal considerations surrounding implementing MITS as standard of care for stillbirths, neonatal and paediatric deaths in SA. Furthermore, based on the data from CHAMPS, we present three pragmatic algorithmic approaches to the wide array of testing options for cost-effectiveness and scalability of postmortem MITS in South African state facilities.

Presence of procoagulant peripheral blood mononuclear cells in severe COVID-19 patients relate to ventilation perfusion mismatch and precede pulmonary embolism.

PURPOSE: Pulmonary emboli (PE) contribute substantially to coronavirus disease 2019 (COVID-19) related mortality and morbidity. Immune cell-mediated hyperinflammation drives the procoagulant state in COVID-19 patients, resulting in immunothrombosis. To study the role of peripheral blood mononuclear cells (PBMC) in the procoagulant state of COVID-19 patients, we performed a functional bioassay and related outcomes to the occurrence of PE. Secondary aims were to relate this functional assay to plasma D-dimer levels, ventilation perfusion mismatch and TF expression on monocyte subsets. METHODS: PBMC from an ICU biobank were obtained from 20 patients with a computed tomography angiograph (CTA) proven PE and compared to 15 COVID-19 controls without a proven PE. Functional procoagulant properties of PBMC were measured using a modified fibrin generation time (MC-FGT) assay. Tissue factor (TF) expression on monocyte subsets were measured by flow cytometry. Additional clinical data were obtained from patient records including end-tidal to arterial carbon dioxide gradient. RESULTS: MC-FGT levels were highest in the samples taken closest to the PE detection, similar to the end-tidal to arterial carbon dioxide gradient (ETCO2 - PaCO2), a measurement to quantify ventilation-perfusion mismatch. In patients without proven PE, peak MC-FGT relates to an increase in end-tidal to arterial carbon dioxide gradient. We identified non-classical, CD16 positive monocytes as the subset with increased TF expression. CONCLUSION: We show that the procoagulant state of PBMC could aid in early detection of PE in COVID-19 ICU patients. Combined with end-tidal to ETCO2 - PaCO2 gradient, these tests could improve early detection of PE on the ICU.

The impact of a decentralised orthopaedic service on tertiary referrals in Cape Town, South Africa.

BACKGROUND: In South Africa (SA), district hospitals (DHs) have limited capacity to manage the high burden of traumatic injuries. Scaling up decentralised orthopaedic care could strengthen trauma systems and improve timely access to essential and emergency surgical care (EESC). Khayelitsha township in Cape Town, SA, has the highest trauma burden in the Cape Metro East health district. OBJECTIVES: The primary objective of this study was to describe the impact of Khayelitsha District Hospital (KDH) on acute orthopaedic services in the health district, with a focus on the volume and type of orthopaedic services provided without tertiary referral. METHODS: This retrospective analysis described acute orthopaedic cases from Khayelitsha and their management between 1 January 2018 and 31 December 2019. Orthopaedic resources and the proportion of cases referred to the tertiary hospital by all DHs in the Cape Metro East health district are described. RESULTS: In 2018 - 2019, KDH performed 2 040 orthopaedic operations, of which 91.3% were urgent or emergencies. KDH had the most orthopaedic resources and the lowest referral ratio (0.18) compared with other DHs (0.92 - 1.35). In Khayelitsha, 2 402 acute orthopaedic cases presented to community health clinics. Trauma (86.1%) was the most common mechanism of injury for acute orthopaedic referrals. Of clinic cases, 2 229 (92.8%) were referred to KDH and 173 (7.2%) directly to the tertiary hospital. The most common reason for direct tertiary referral was condition related (n=157; 90.8%). CONCLUSION: This study outlines a successful example of a decentralised orthopaedic surgical service that increased EESC accessibility and alleviated the high burden of tertiary referrals compared with other DHs with fewer resources. Further research on the barriers to scaling up orthopaedic DH capacity in SA is needed to improve equitable access to surgical care.

Estimating carnivoran diets using a combination of carcass observations and scats from GPS clusters.

Scat analysis is one of the most frequently used methods to assess carnivoran diets and Global Positioning System (GPS) cluster methods are increasingly being used to locate feeding sites for large carnivorans. However, both methods have inherent biases that limit their use. GPS methods to locate kill sites are biased towards large carcasses, while scat analysis over-estimates the biomass consumed from smaller prey. We combined carcass observations and scats collected along known movement routes, assessed using GPS data from four African lion (Panthera leo) prides in the Kruger National Park, South Africa, to determine how a combination of these two datasets change diet estimates. As expected, using carcasses alone under-estimated the number of feeding events on small species, primarily impala (Aepyceros melampus) and warthog (Phacochoerus africanus), in our case by more than 50% and thus significantly under-estimated the biomass consumed per pride per day in comparison to when the diet was assessed using carcass observations alone. We show that an approach that supplements carcass observations with scats that enables the identification of potentially missed feeding events increases the estimates of food intake rates for large carnivorans, with possible ramifications for predator-prey interaction studies dealing with biomass intake rate.

WhatsApp-propriate? A retrospective content analysis of WhatsApp use and potential breaches in confidentiality among a team of doctors at a district hospital, South Africa.

BACKGROUND: There has been a steady increase in the use of electronic media and instant messaging among healthcare professionals, where it has been almost universally adopted in the workplace. The use of WhatsApp and its perceived benefits in healthcare have been extensively studied; however, there are concerns regarding the potential for ethical breaches in confidentiality through shared electronic patient information. OBJECTIVES: To identify the usage characteristics and incidence of shared patient information with WhatsApp use in a team of medical doctors in an unobserved and unregulated setting. METHODS: We conducted a retrospective cross-sectional content analysis of WhatsApp messages (n=3 340) among a team of 20 doctors in a South African district hospital over 6 months. All messages found within this time period were allocated unique identifiers. The text and image messages were thematically grouped into four categories, i.e. clinical care, resource allocation, social and administrative. Messages that contained patient-identifying information were included in the analysis. RESULTS: Of a total of 3 340 messages sent, 220 (6.6%) contained patient-identifying information. Of these, 109 (3.3%) contained non-anonymised patient information, while in 111 (3.3%) messages, the information was anonymised. The likelihood of sharing patient identifiers was proportionally much higher in shared images (odds ratio (OR) 5.1; 95% confidence interval (CI) 3.2 - 8.2; p<0.0001) compared with text messages, and in messages that related to clinical care (OR 9.3; 95% CI 2.2 - 38.8; p=0.0023) compared with those sent for resource allocation, and social or administrative purposes. CONCLUSIONS: Non-anonymised patient identifiers were found in 3.3% of messages, constituting the potential for breaching patient confidentiality. While WhatsApp groups have significant utility in co-ordinating aspects of clinical care, resource allocation, as well as social and administrative functions, the safe use of WhatsApp should be promoted to ensure that patient confidentiality is maintained.

HIV-associated and idiopathic-acquired haemophilia A: A single-centre case series from Cape Town, South Africa.

Acquired haemophilia A is a rare coagulation disorder, which can lead to life-threatening haemorrhages if not identified and treated promptly. It is characterised by the presence of autoantibodies (inhibitors) to factor VIII. Acquired haemophilia A associated with HIV is a rare but well described phenomenon with limited directions to its management. We comparatively describe four patients - two with HIV and two without - that presented with unusual bleeding episodes with a prolonged activated partial thromboplastin time secondary to factor VIII inhibitors. An empiric observation is that the patients with acquired haemophilia A associated with HIV had higher antibody titres at presentation, that required more prolonged immunosuppressive therapy to induce remission.

Molecular monitoring of African swine fever virus using surveys targeted at adult ornithodoros ticks: a re-evaluation of Mkuze game reserve, South Africa.

The Mkuze Game Reserve (MGR), in north-eastern KwaZulu-Natal Province, South Africa is an African swine fever virus (ASF) controlled area. In a survey conducted in 1978, ASF prevalence in warthogs and Ornithodoros ticks in MGR was determined to be 2% and 0.06%, respectively. These values, acknowledged as being unusually low compared to other East and southern African ASF-positive sylvatic-cycle host populations, have not been assessed since. The availability of a sensitive PCR-based virus detection method, developed specifically for the sylvatic tampan host, prompted a re-evaluation of ASF virus (ASFV) prevalence in MGR ticks. Of the 98 warthog burrows inspected for Ornithodoros presence, 59 (60.2%) were found to contain tampans and tick sampling was significantly male-biased. Whilst gender sampling-bias is not unusual, the 27% increase in infestation rate of warthog burrows since the 1978 survey is noteworthy as it anticipates a concomitant increase in ASFV prevalence, particularly in light of the high proportion (75%) of adult ticks sampled. However, despite DNA integrity being confirmed by internal control amplification of the host 16S gene, PCR screening failed to detect ASFV. These results suggest that ASFV has either disappeared from MGR or if present, is localized, occurring at exceptionally low levels. Further extensive surveys are required to establish the ASFV status of sylvatic hosts in this controlled area.

Browsing lawns? Responses of Acacia nigrescens to ungulate browsing in an African savanna.

We measured browsing-induced responses of Acacia trees to investigate "browsing lawns" as an analogy to grazing lawns in a semiarid eutrophic African savanna. During the two-year field study, we measured plant tolerance, resistance, and phenological traits, while comparing variation in leaf nitrogen and specific leaf area (SLA) across stands of Acacia nigrescens, Miller, that had experienced markedly different histories of attack from large herbivores. Trees in heavily browsed stands developed (1) tolerance traits such as high regrowth abilities in shoots and leaves, high annual branch growth rates, extensive tree branching and evidence of internal N translocation, and (2) resistance traits such as close thorn spacing. However, phenological "escape" responses were weak even in heavily browsed stands. Overall, browsing strongly affected plant morpho-functional traits and decreased both the number of trees carrying pods and the number of pods per tree in heavily browsed stands. Hence, there is experimental evidence that tolerance and resistance traits may occur simultaneously at heavily browsed sites, but this comes at the expense of reproductive success. Such tolerance and resistance traits may coexist if browsers trigger and maintain a positive feedback loop in which trees are continually investing in regrowth (tolerance), and if the plant's physical defenses (resistance) are not nutritionally costly and are long-lived. Our results confirm that chronic browsing by ungulates can maintain A. nigrescens trees in a hedged state that is analogous to a grazing lawn. Further research is needed to fully understand the long-term effects of chronic browsing on reproduction within such tree populations, as well as the overall effects on nutrient cycling at the ecosystem level.

Acrocallosal syndrome in two African brothers born to consanguineous parents.

We describe two mentally retarded brothers with craniofacial anomalies, polydactyly, and other clinical manifestations compatible with the acrocallosal syndrome (ACS). These are the first black patients from Africa with this diagnosis. They are also the fourth set of sibs described with ACS, and together with the parental consanguinity documented in this family, confirm autosomal recessive inheritance of this syndrome. The clinical manifestations in our patients confirm the intrafamilial variability of the syndrome. Postnatal onset of growth retardation is proposed as an additional manifestation of ACS.

Acute effect of sodium cromoglycate on airway narrowing induced by 4.5 percent saline aerosol. Outcome before and during treatment with aerosol corticosteroids in patients with asthma.

STUDY OBJECTIVE: To investigate the acute effect of sodium cromoglycate on airway responses to 4.5 percent saline aerosol challenge, before and during treatment with inhaled budesonide--a corticosteroid. DESIGN: Open study, with a total of five visits, two before budesonide treatment, and three follow-up visits, two between 5 and 6 weeks and one at more than 11 weeks. SETTING: Referral-based Respiratory Investigation Unit at Royal Prince Alfred Hospital, a major Sydney-based teaching hospital. PATIENTS: Eleven patients with asthma (ten atopic), with a PD20 FEV1 to 4.5 percent saline aerosol challenge and about to commence inhaled budesonide for treatment of their asthma. INTERVENTIONS: The 40 mg of sodium cromoglycate was inhaled before a 4.5 percent NaCl challenge, both before and after regular (36 +/- 9 d) treatment with budesonide (1,000 micrograms/d). The final challenge was repeated in ten subjects after 11 weeks or more of treatment with budesonide. MEASUREMENTS AND RESULTS: Sensitivity to 4.5 percent saline aerosol was measured as the dose of saline aerosol required to induce a 20 percent fall in FEV1 (PD20). Reactivity was measured as the dose-response slope by taking the percent fall in FEV1 and dividing it by the dose required to induce the fall. On the control day the geometric mean PD20 (95 percent CI) for 4.5 percent saline aerosol was 2.8 (1.4 to 5.4) and the dose response slope (DRS) 5.6 (2.9-11.1). An acute dose of sodium cromoglycate reduced sensitivity (PD20) by 8-fold and reactivity (DRS) 12.3-fold. This effect was similar in magnitude to that measured after regular treatment with budesonide alone. When sodium cromoglycate was given during treatment with budesonide, the PD20 was reduced 16-fold and the DRS 42-fold, and this was greater than the reduction with budesonide taken for 3 months (p < 0.03, p < 0.05 respectively). CONCLUSIONS: Sodium cromoglycate inhibits responses to 4.5 percent saline aerosol and has additional benefits to those conferred by aerosol steroids. The mechanism for responsiveness to saline aerosol and efficacy of these drugs may relate to alteration in chloride ion channel regulation by inflammation.

Duration of protection by inhaled salmeterol in exercise-induced asthma.

Beta-adrenoceptor agonists such as albuterol are very effective in preventing exercise-induced asthma (EIA) when they are given as an aerosol immediately before exercise. However, their duration of protection against EIA is usually less than 2 h. This may be due partly to their rapid clearance from the airways. Salmeterol is a highly lipophylic compound that is thought to bind to an exoreceptor near the beta-receptor. The objective of this study was to compare the protective effect of salmeterol with albuterol against EIA. Exercise was performed 0.5, 2.5, 4.5, and 6.5 hours after administration of the active drugs. Subjects attended the laboratory on four days within six weeks and cycled for 8 min breathing dry compressed air. We studied 17 asthmatic subjects (aged 19 to 49 years) with moderate to severe EIA. Salmeterol (50 micrograms) or albuterol (200 micrograms) was given from a metered dose inhaler via a spacer (Volumatic). On the control day, the mean work load +/- 1 SD was 174 +/- 47 W, ventilation (VE) was 77.9 percent +/- 11.2 percent of the target ventilation (60 percent maximum voluntary ventilation [MVV]), and heart rate was 170 +/- 14 beats per minute. This intensity was maintained for all tests. FEV1 was measured before and after exercise and was expressed as percent predicted and as percentage of the preexercise value (percentage of fall). Thirty minutes after treatment, both drugs were effective in inhibiting EIA--percentage of fall in FEV1, 17 +/- 12 after salmeterol; percentage of fall in FEV1, 15 +/- 15 after albuterol. At 2.5, 4.5, and 6.5 hours, the reduction in FEV1 was significantly less (p less than 0.01) after salmeterol compared with albuterol. At 6.5 hours, the percentage of fall in FEV1 was 20 +/- 10 after salmeterol and 36 +/- 12 after albuterol. Salmeterol also had a more prolonged action as a bronchodilator and values for FEV1 were significantly higher compared with those on albuterol at 4.5 and 6.5 hours. At 6.5 hours, the FEV1 percent predicted was 96 +/- 10 after salmeterol and 84 +/- 12 after albuterol (p less than 0.01). We conclude that the extent of protection against EIA and the bronchodilation induced by both drugs was similar, but that salmeterol has a longer duration of action compared with albuterol. The reason for its superior duration of action may be due to a slower clearance of the drug from the airways.

Cervical cytologic screening among females with nongynecologic hospital admissions.

Routine vaginal cytologic screening in nongynecologic admissions to Tygerberg Hospital revealed a detection rate for pelvic neoplasia of 9.3/1000 patients. Of these, 22 (16%) did not derive any benefit from this program because of the severity of the primary extrapelvic disease. However, 57% of those detected were still in the in situ stage and should have a 100% 5-year survival. The treatment was considered to be complete in 54.4% of the cases. As this service is performed by nursing personnel as part of their daily duty, this program seems to be a sound economic proposition.

Home range - body mass relations: a field study on African browsing ruminants.

Home range data were collected concurrently from four syntopic browsing ruminant species in a conserved savanna ecosystem. Mean home range areas were: giraffe (Giraffa camelopardalis) 282 km2; kudu (Tragelaphus strepsiceros) 21.9 km2; impala (Aepyceros melampus) 5.82 km2; steenbok (Raphicerus campestris) 0.62 km2. Home range area (A hr) scaled on body mass (M) as: A hr=0.024 M 1.38 (r 2=0.99).