https://commons.ufh.ac.za/vital/access/manager/Index ${session.getAttribute("locale")} 5 https://commons.ufh.ac.za/vital/access/manager/Repository/vital:41962 Wed 26 Oct 2022 16:01:49 SAST ]]> https://commons.ufh.ac.za/vital/access/manager/Repository/vital:42178 Wed 12 May 2021 15:05:54 SAST ]]> https://commons.ufh.ac.za/vital/access/manager/Repository/vital:41920 Wed 12 May 2021 15:01:32 SAST ]]> https://commons.ufh.ac.za/vital/access/manager/Repository/vital:42174 Wed 12 May 2021 15:00:21 SAST ]]> https://commons.ufh.ac.za/vital/access/manager/Repository/vital:42195 Wed 12 May 2021 14:51:36 SAST ]]> https://commons.ufh.ac.za/vital/access/manager/Repository/vital:42454 Wed 12 May 2021 14:45:08 SAST ]]> https://commons.ufh.ac.za/vital/access/manager/Repository/vital:42957 Wed 12 May 2021 14:35:33 SAST ]]> https://commons.ufh.ac.za/vital/access/manager/Repository/vital:42198 Wed 12 May 2021 14:30:44 SAST ]]> https://commons.ufh.ac.za/vital/access/manager/Repository/vital:42052 Wed 12 May 2021 14:30:41 SAST ]]> https://commons.ufh.ac.za/vital/access/manager/Repository/vital:42171 Wed 12 May 2021 14:22:34 SAST ]]> https://commons.ufh.ac.za/vital/access/manager/Repository/vital:42172 Wed 12 May 2021 13:59:27 SAST ]]> https://commons.ufh.ac.za/vital/access/manager/Repository/vital:41938 Wed 12 May 2021 13:58:42 SAST ]]> https://commons.ufh.ac.za/vital/access/manager/Repository/vital:42051 Wed 12 May 2021 13:56:47 SAST ]]> https://commons.ufh.ac.za/vital/access/manager/Repository/vital:42175 Wed 12 May 2021 13:49:43 SAST ]]> https://commons.ufh.ac.za/vital/access/manager/Repository/vital:42201 Tue 15 Aug 2023 11:29:30 SAST ]]> https://commons.ufh.ac.za/vital/access/manager/Repository/vital:42759 10 m depth) and inshore sites (intertidal surf zones). Many sites in the bay, especially the atypical site at Cape Recife, exhibit higher than the average pH levels (>8.04), suggesting that pH variability may be biologically driven. This is further evidenced by high diurnal variability in pH (~0.55 pH units). Although the specific drivers of the high pH variability in Algoa Bay could not be identified, baseline carbonate chemistry conditions were identified, which is necessary information to design and interpret biological experiments. Long-term, continuous monitoring is required to improve understanding of the drivers of pH variability in understudied coastal regions, like Algoa Bay. A local fisheries species, D. capensis, was selected as a model species to assess the impacts of future OA scenarios in Algoa Bay. It was hypothesized that this temperate, coastally distributed species would be adapted to naturally variable pH conditions and thus show some tolerance to low pH, considering that they are exposed to minimum pH levels of 7.77 and fluctuations of up to 0.55 pH units. Laboratory perturbation experiments were used to expose early postflexion stage of D. capensis to a range of pH treatments that were selected based on the measured local variability (~8.0–7.7 pH), as well as future projected OA scenarios (7.6–7.2 pH). Physiological responses were estimated using intermittent flow respirometry by quantifying routine and active metabolic rates as well as relative aerobic scope at each pH treatment. The behavioural responses of the larvae were also assessed at each pH treatment, as activity levels, by measuring swimming distance and speed in video-recording experiments, as well as feeding rates. D. capensis had sufficient physiological capacity to maintain metabolic performance at pH levels as low as 7.27, as evidenced by no changes in any of the measured metabolic rates (routine metabolic rate, active metabolic rate, and relative aerobic scope) after exposure to the range of pH treatments (8.02–7.27). Feeding rates of D. capensis were similarly unaffected by pH treatment. However, it appears that subtle increases in activity level (measured by swimming distance and swimming speed experiments) occur with a decrease in pH. These changes in activity level were a consequence of a change in behaviour rather than metabolic constraints. This study concludes, however, that based on the parameters measured, there is no evidence for survival or fitness related consequences of near future OA on D. capensis. OA research is still in its infancy in South Africa, and the potential impacts of OA to local marine resources has not yet been considered in local policy and resource management strategies. Integrating field monitoring and laboratory perturbation experiments is emerging as best practice in OA research. This is the first known study on the temperate south coast of South Africa to quantify local pH variability and to use this information to evaluate the biological response of a local species using relevant local OA scenarios as treatment levels for current and near future conditions. Research on local conditions in situ and the potential impacts of future OA scenarios on socio-economically valuable species, following the model developed in this study, is necessary to provide national policy makers with relevant scientific data to inform climate change management policies for local resources.]]> Thu 29 Sep 2022 12:42:34 SAST ]]> https://commons.ufh.ac.za/vital/access/manager/Repository/vital:42109 80%. The formulation composition identified was subsequently used for the optimization of the manufacturing parameters viz. sonication time and amplitude, using a Central Composite Design (CCD) . The LC and EE, in vitro CLA release, cytotoxicity, osmolarity, pH, degree of crystallinity and lipid modification, elemental analysis and surface morphology of the optimized batch was investigated and mon itored to ensure that CLA - loaded NLC, of the desirable quality, had been produced. On the day of manufacture the mean PS and PDI of the optimized CLA - loaded NLC formulation adjusted to physiological osmolarity (250 – 450 mOsm/kg) was 461.9 ± 40.16 nm and 0. 523 ± 0.104, respectively. The ZP for the optimized NLC generated on the day of manufacture using HPLC grade water as the dispersion medium was - 20.5 ± 4.82 mV. The pH and osmolarity of the optimized CLA - loaded NLC formulation was 7.76 ± 0.01 and 316 ± iii 2 m Osm/Kg, respectively and the EE was 88.62 ± 0.23 %. The optimized NLC exhibited a decreased crystallinity in comparison to the bulk lipid materials. DSC, WAXS and FT - IR revealed that CLA was molecularly dispersed in the nanocarriers. The optimized CLA - load ed NLC exhibited muco - adhesive properties, when tested under stationary conditions using laser doppler anemometry (LDA). The optimized formulation also exhibited sustained release of CLA over 24 hours during in vitro release testing and CLA release was bes t described using the Baker - Lonsdale model . The cumulative % CLA released over 24 hours was 56.13 ± 0.23% and mass balance analysis revealed 41.38 ± 0.02% CLA had been retained in the NLC. In vitro cytotoxicity testing revealed that the optimized CLA - NLC w ere less cytotoxic to HeLa cells when compared to CLA alone and further confirmed that the lipids and excipients used in these studies were of GRAS status . Stability studies revealed that the EE reduced over 28 days by 14.42% and 5.14% when stored at 4 °C and 22 °C , respectively. In addition, the particle size increased from the nm to μm range for samples stored at 22 °C. The findings are a good starting point but require further optimization to ensure prolongation of stability. In addition , the technology requires additional developmental studies and a powder for reconstitution for use as a single - dose considered as single dose packaging may be a solution to the compromised formulation stability observed in these studies. The CLA - NLC produced in these stu dies exhibit sound product attributes which serve as a useful foundation for the novel delivery of antibiotics to the eye. The results suggest that the optimized NLC have the potential to enhance precorneal retention and increase ocular availability of CLA , which in turn may be useful to reduce the required dose and dosing frequency when administering CLA as a reconstituted solution to treat susceptible organisms that infect ocular tissues.]]> Fri 06 Aug 2021 09:14:42 SAST ]]>