https://vital.seals.ac.za/vital/access/manager/Index ${session.getAttribute("locale")} 5 https://vital.seals.ac.za/vital/access/manager/Repository/vital:10495 Wed 12 May 2021 23:47:26 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:8369 Wed 12 May 2021 23:15:46 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10500 Wed 12 May 2021 23:00:25 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4689 Wed 12 May 2021 22:55:56 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9322 Wed 12 May 2021 22:55:53 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:6045 Wed 12 May 2021 22:42:16 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9587 Wed 12 May 2021 22:41:21 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:26408 Wed 12 May 2021 22:39:17 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9329 Wed 12 May 2021 22:36:36 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10358 Wed 12 May 2021 22:29:58 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10070 Wed 12 May 2021 22:17:44 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3249 Wed 12 May 2021 20:36:10 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4725 Wed 12 May 2021 20:25:10 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:1327 Wed 12 May 2021 20:23:16 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:5944 Wed 12 May 2021 20:18:16 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:26623 Wed 12 May 2021 20:17:12 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:5364 Wed 12 May 2021 19:59:16 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:2325 Wed 12 May 2021 19:46:38 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:26461 5% per liver weight in all treated groups. The present study demonstrates that these two plant extracts and metformin have different glucogenic and lipogenic effects from that presented by HFD alone when compared to the LFD alone. In conclusion, metformin and P. africana extract can attenuate HFD‐induced fatty liver without changing the dietary habits. Hence S. frutescens extract is less effective in the prevention of HFD‐induced fatty liver. A change in the dietary habits is recommended to be considered during the use of these three remedies in the treatment of HFD‐induced insulin resistance and fatty liver. All three treatments enhanced antioxidant capacity, and may improve insulin resistance and fatty liver mediated by the present HFD through different mechanism of actions in the liver.]]> Wed 12 May 2021 19:40:44 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4698 Wed 12 May 2021 19:29:19 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:16152 Wed 12 May 2021 19:24:53 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9726 Wed 12 May 2021 19:20:11 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3630 Wed 12 May 2021 19:11:50 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:5855 Wed 12 May 2021 19:02:24 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:21116 Wed 12 May 2021 18:57:10 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3372 Wed 12 May 2021 18:54:33 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4103 Wed 12 May 2021 18:47:03 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4486 Wed 12 May 2021 18:44:44 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:1980 Wed 12 May 2021 18:37:19 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9822 Wed 12 May 2021 18:35:23 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10554 Wed 12 May 2021 18:33:02 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:2516 Wed 12 May 2021 18:28:30 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:2164 Wed 12 May 2021 17:43:45 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:26607 Wed 12 May 2021 17:33:21 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:5519 Wed 12 May 2021 17:12:10 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4497 2500 μg/mL) and did not show any activity against the yeast, C. albicans. The second set of compounds consisted of the silver(I) complexes containing 2-hydroxymethyl-N-alkylimidazoles. The complexes displayed a broad spectrum antimicrobial activity towards the microorganisms that were tested and their activity [E. coli (MIC = 5-40 μg/mL), S. aureus (MIC = 20-80 μg/mL), Bacillus subtilis subsp. spizizenii (MIC = 5-40 μg/mL) and C. albicans (MIC = 40-80 μg/mL)] increased with the alkyl chain length of the 2-hydroxymethyl-N-alkylimidazole. The third set of compounds consisted of the vinylimidazoles containing the vinyl group either at the 1-position or at the 4- or 5- position. The imidazoles with the vinyl group at the 4- or 5-position contained the alkyl group (decyl) at the 1-position. For the fabrication of the antimicrobial nanofibers, the first two sets of imidazole derivatives (2-substituted N-alkylimidazoles and silver(I) complexes) were incorporated into electrospun nylon 6 nanofibers while the third set (2-substituted vinylimidazoles) was immobilized onto electrospun nylon 6 nanofibers employing the graft polymerization method. The antimicrobial nylon nanofibers were characterized by IR spectroscopy and SEM-EDAX (EDS). The electrospun nylon 6 nanofibers incorporated with 2-substituted N-alkylimidazoles displayed moderate to excellent levels of growth reduction against S. aureus (73.2-99.8 percent). For the electrospun nylon 6 nanofibers incorporated with silver(I) complexes, the levels of growth reduction were >99.99 percent, after the antimicrobial activity evaluation using the shake flask method. Furthermore, the grafted electrospun nylon 6 nanofibers showed excellent levels of growth reduction for E. coli (99.94-99.99 percent) and S. aureus (99.93-99.99 percent). The reusability results indicated that the grafted electrospun nylon 6 nanofibers maintained the antibacterial activity until the third cycle of useage. The cytotoxicity studies showed that grafted electrospun nylon 6 nanofibers possess lower cytotoxic effects on Chang liver cells with IC50 values in the range 23.48-26.81 μg/mL. The thesis demonstrated that the development of antimicrobial electrospun nanofibers, with potential for the eradication of pathogenic microoganisms in water, could be accomplished by incorporation as well as immobilization strategies.]]> Wed 12 May 2021 16:49:28 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:21793 Wed 12 May 2021 16:46:37 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:1964 Wed 12 May 2021 16:42:11 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:8244 Wed 12 May 2021 16:20:41 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:26751 Wed 12 May 2021 16:19:00 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9326 Wed 12 May 2021 16:12:24 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4498 99%), thus producing polar sulfones which are extractible by polar solid phase extractants. Adsorption of the polar sulfone compounds was carried-out by employing MIPs which were fabricated through the formation of recognition sites complementary to oxidized sulfur-containing compounds (sulfones) on electrospun polybenzimidazole (PBI) nanofibers, cross-linked chitosan microspheres and electrospun chitosan nanofibers. Adsorption of benzothiophene sulfone (BTO₂), dibenzothiophene sulfone (DBTO₂) and 4,6-dimethyldibenzothiophene sulfone (4,6-DMDBTO₂) on the various molecularly imprinted adsorbents presented a Freundlich (multi-layered) adsorption isotherm which indicated interaction of adsorbed organosulfur compounds. Maximum adsorption observed for BTO₂, DBTO₂ and 4,6-DMDBTO₂ respectively was 8.5 ± 0.6 mg/g, 7.0 ± 0.5 mg/g and 6.6 ± 0.7 mg/g when imprinted chitosan nanofibers were employed, 4.9 ± 0.5 mg/g, 4.2 ± 0.7 mg/g and 3.9 ± 0.6 mg/g on molecularly imprinted chitosan microspheres, and 28.5 ± 0.4 mg/g, 29.8 ± 2.2 mg/g and 20.1 ± 1.4 mg/g on molecularly imprinted PBI nanofibers. Application of electrospun chitosan nanofibers on oxidized hydro-treated diesel presented a sulfur removal capacity of 84%, leaving 62 ± 3.2 ppm S in the fuel, while imprinted PBI electrospun nanofibers displayed excellent sulfur removal, keeping sulfur in the fuel after the oxidation/adsorption below the determined limit of detection (LOD), which is 2.4 ppm S. The high level of sulfur removal displayed by imprinted PBI nanofibers was ascribed to hydrogen bonding effects, and π-π stacking between aromatic sulfone compounds and the benzimidazole ring which were confirmed by chemical modelling with density functional theory (DFT) as well as the imprinting effect. The home-made pressurized hot water extraction (PHWE) system was applied for extraction/desorption of sulfone compounds adsorbed on the PBI nanofibers at a flow rate of 1 mL/min and at 150°C with an applied pressure of 30 bars. Application of molecularly imprinted PBI nanofibers for the desulfurization of oxidized hydro-treated fuel showed potential for use in refining industries to reach ultra-low sulfur fuel level, which falls below the 10 ppm sulfur limit which is mandated by the environmental protection agency (EPA) from 2015.]]> Wed 12 May 2021 15:53:07 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:1995 Wed 12 May 2021 15:47:01 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:2881 Thu 13 May 2021 15:46:00 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4464 Thu 13 May 2021 14:21:31 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:1979 Thu 13 May 2021 11:32:22 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4105 Thu 13 May 2021 10:52:51 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:26580 99 % in selectively extracting the metalloporphyrins. The impact of the template on the affinity of recognition for NTPP was evaluated. The results showed that the NTPP adsorption capacity increased as the molar ratio of NTPP to styrene was increased from 1:1 to 3:1. The optimal ratio of template to functional monomer which yielded the best specific affinity and highest recovery (99.9 %) was 3:1. The effects of trifluoroacetic acid (TFA), dichloromethane (DCM), dimethyl sulphoxide (DMSO), pentane (PEN) on electro-spinnability of the polymer solutions and the morphological appearance of the nanofibers were investigated. The imprinted nanofibers exhibited the same selectivity specialism for both NTPP and VTPP. A remarkable stability in relation to reusability was observed when imprinted nanofibers were used, as they could be reused nine times without incurring any significant loss in removal efficiency. The results were validated by analysing a certified reference material. The imprinted sorbents were therefore found to be selective sorbents that are well suited for handling trace metals in organic media.]]> Thu 13 May 2021 09:54:20 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9727 Thu 13 May 2021 09:35:39 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:1326 Thu 13 May 2021 09:30:16 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4778 Thu 13 May 2021 08:53:57 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:1199 Thu 13 May 2021 08:18:24 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9642 Thu 13 May 2021 08:04:51 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:28540 Thu 13 May 2021 07:35:41 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:8430 Thu 13 May 2021 07:33:41 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:29380 20% habitat loss due to invasion). Upstream invasion by centrarchids isolated and fragmented P. afer populations into headwater refugia, while top down invasion by salmonids excluded B. trevelyani from invaded, more pristine stream reaches, by forcing the species into degraded unsuitable lower stream reaches. Predation also disrupted population processes such as adult dispersal for P. afer, and centrarchid-invaded zones acted as demographic sinks, where adults dispersing through invaded reaches were rapidly depleted. While the Mandela lineage of P. afer exhibited little within or between drainage genetic structuring, B. trevelyani was >4% divergent between drainages, and up to 2% divergent between streams within the Keiskamma River system (Chapter 7). The distribution of genetic diversity for B. trevelyani also indicated that the loss of diversity was imminent without immediate conservation interventions. This thesis has provided conclusive evidence that native fishes are vulnerable to invasion and that non-native predatory fishes have significant impacts on native fishes in Eastern Cape headwater streams. If management and conservation measures are implemented, the unwanted introduction and spread of non-native fishes may be restricted, allowing native fishes opportunities for recovery.]]> Thu 13 May 2021 07:28:56 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:5155 Thu 13 May 2021 07:27:29 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10670 Thu 13 May 2021 07:19:36 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:5388 Thu 13 May 2021 07:10:52 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:1324 Thu 13 May 2021 06:43:15 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4563 Thu 13 May 2021 06:38:31 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4535 Thu 13 May 2021 06:36:49 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:26533 Thu 13 May 2021 06:31:30 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3370 Thu 13 May 2021 06:25:53 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:2003 Thu 13 May 2021 06:16:30 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3211 Thu 13 May 2021 06:11:58 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3646 Thu 13 May 2021 06:00:50 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10550 Thu 13 May 2021 05:57:43 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:5882 Thu 13 May 2021 05:49:20 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:1968 Thu 13 May 2021 05:36:23 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:1976 Thu 13 May 2021 05:19:48 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:6043 Thu 13 May 2021 04:31:00 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:5426 Thu 13 May 2021 04:17:52 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:5877 1 yr in the absence of herbivores) and showed that sea urchins and browsing fishes were able to remove significant amounts of macroalgae where either herbivore was abundant. However, using multiple-choice selectivity assays and in situ video recordings, I found that browsing fishes fed very selectively with low overlap in diet among species, leading to low functional redundancy within a high diversity system. Finally, using long-term survey data (from 28 sites) to build a 43-year chronosequence, I showed that it is possible that the effects of herbivory will not be constant across transitions from open fishing to fishery closures through non-linear grazing intensity. Therefore, increases in herbivory within fisheries closures may not be immediate and may allow a window of opportunity for algae to go from turf to unpalatable macroalgae until scraping and browsing fishes fully recover from fishing (~ 20 years). The findings in this thesis are novel and raise concern over the potential implications of the slow recovery of parrotfishes or, given lower than expected functional redundancy in grazing effects, the absence of even one browsing fish species in fisheries closures. Overall, this thesis highlights the importance of herbivore community dynamics in mediating interactions among algae, and provides new insights for conservation and management actions that attempt to bolster the resilience of coral reefs.]]> Thu 13 May 2021 04:09:10 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:20615 Thu 13 May 2021 03:57:36 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4457 Thu 13 May 2021 03:30:35 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:39453 Thu 13 May 2021 03:28:24 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:2326 Thu 13 May 2021 03:23:33 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:5846 Thu 13 May 2021 03:19:43 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4108 Thu 13 May 2021 03:02:47 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4691 Thu 13 May 2021 03:01:40 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:2004 Thu 13 May 2021 03:00:34 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10350 Thu 13 May 2021 02:45:06 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:1966 Thu 13 May 2021 02:30:31 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:5870 Thu 13 May 2021 02:28:03 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4117 Thu 13 May 2021 02:12:44 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4109 Thu 13 May 2021 01:52:04 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:1325 Thu 13 May 2021 01:50:11 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3719 Thu 13 May 2021 01:37:42 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10643 Thu 13 May 2021 01:30:41 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10582 Thu 13 May 2021 01:30:28 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:20983 Thu 13 May 2021 01:13:37 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:6046 Thu 13 May 2021 01:12:38 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9716 Thu 13 May 2021 01:08:14 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10355 Thu 13 May 2021 01:04:00 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10363 Thu 13 May 2021 01:01:02 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4114 Thu 13 May 2021 00:22:21 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:5359 Thu 13 May 2021 00:19:27 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9641 Thu 13 May 2021 00:13:20 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:1985 Thu 06 Apr 2023 14:25:46 SAST ]]>