https://commons.ru.ac.za/vital/access/manager/Index ${session.getAttribute("locale")} 5 https://commons.ru.ac.za/vital/access/manager/Repository/vital:70097 Wed 29 Nov 2023 11:14:39 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:68309 Wed 24 Apr 2024 16:20:07 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:43832 Wed 24 Apr 2024 13:36:11 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:43874 Wed 24 Apr 2024 13:35:38 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:43873 Wed 24 Apr 2024 13:34:35 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:44704 Wed 15 May 2024 10:36:36 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:50203 Wed 15 May 2024 10:36:00 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:50195 Wed 15 May 2024 10:35:22 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:50196 Wed 15 May 2024 10:34:40 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:44700 Wed 15 May 2024 10:34:09 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:50087 Wed 15 May 2024 10:33:09 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:28087 Wed 15 Mar 2023 09:37:04 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:71460 Wed 14 Aug 2024 15:27:45 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:71635 Wed 14 Aug 2024 09:02:55 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:75340 Wed 11 Sep 2024 11:54:12 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:75339 Wed 11 Sep 2024 11:49:14 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:55696 Wed 08 May 2024 19:47:54 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:55699 Wed 08 May 2024 19:45:20 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:50079 Wed 08 May 2024 15:06:26 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:50088 Wed 08 May 2024 15:04:46 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:44735 Wed 08 May 2024 15:04:12 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:50090 Wed 08 May 2024 15:03:38 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:44736 Wed 08 May 2024 15:03:07 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:44711 Wed 08 May 2024 15:02:33 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:50567 Wed 08 May 2024 15:02:05 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:44727 Wed 08 May 2024 15:01:39 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:44686 Wed 08 May 2024 14:56:39 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:74691 Wed 07 Aug 2024 15:55:21 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:72051 Wed 07 Aug 2024 15:48:21 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:74687 Wed 07 Aug 2024 15:48:20 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:74688 α-HCH > δ-HCH > β-HCH. Steric considerations and a molecular orbital theory approach can be used to rationalize the enantioselective nature of the catalysis based on the ease of approach of each Cl atom to the central Fe(I) ion and a consideration of the nodes on the C–Cl bonds that weaken these bonds in a manner that results in bond cleavage and the formation of an Fe–Cl bond.]]> Wed 07 Aug 2024 15:48:18 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:76330 Wed 06 Nov 2024 08:41:02 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:50209 Wed 05 Feb 2025 10:54:51 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:62790 Tue 28 Mar 2023 10:20:37 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:74222 Tue 27 Aug 2024 16:02:13 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:74212 Tue 27 Aug 2024 12:37:19 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:74207 Tue 27 Aug 2024 12:36:59 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:50071 Tue 18 Jul 2023 21:31:00 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:75510 80% of total diet in some cases) indicat-ed that cross‐boundary trophic linkages via odonates are strong in the Kowie River.]]> Tue 17 Sep 2024 11:18:14 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:75508 Tue 17 Sep 2024 11:09:18 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:44266 75 within 15 minutes. The effect of carbon nanotubes (as solid nano-sorbents) on the membrane performance and EME efficiency was evaluated. The method was linear over the range of 10-1000 ng/mL for zolpidem (R2 >0.9991) with repeatability (%RSD) between 0.3 % and 7.3 % (n = 3). The limits of detection and quantitation were 3 and 10 ng/mL, respectively. The sensitivity of HPLC-UV for the determination of zolpidem was enhanced by electromembrane extraction. Finally, the method was employed for the quantitation of zolpidem in biological samples with relative recoveries in the range of 60-79 %.]]> Tue 14 May 2024 11:52:00 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:44006 Tue 14 May 2024 10:59:25 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:28475 Tue 14 Mar 2023 08:48:02 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:70334 Tue 13 Aug 2024 15:34:01 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:43131 Tue 07 May 2024 14:06:40 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:69151 Tue 07 May 2024 08:54:19 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:43153 Tue 07 May 2024 08:28:01 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:72948 Tue 04 Jun 2024 11:40:20 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:75286 Tue 03 Sep 2024 09:05:15 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:68301 Thu 29 May 2025 15:22:01 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:43340 Thu 29 Feb 2024 13:48:57 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:74142 Thu 29 Aug 2024 16:20:49 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:71345 Thu 29 Aug 2024 09:23:06 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:75233 Thu 29 Aug 2024 08:36:53 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:75890 Thu 24 Oct 2024 13:20:53 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:75971 Thu 24 Oct 2024 13:06:52 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:76630 Thu 21 Nov 2024 05:28:27 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:77956 Thu 20 Mar 2025 10:25:22 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:75542 Thu 19 Sep 2024 10:38:32 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:68717 Thu 16 May 2024 05:21:52 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:28307 Thu 11 Apr 2024 19:25:38 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:43872 Thu 09 May 2024 06:25:54 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:28430 Thu 09 Mar 2023 13:07:21 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:28128 Thu 09 Mar 2023 13:00:25 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:28428 Thu 09 Mar 2023 11:57:44 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:77707 Thu 06 Mar 2025 10:13:16 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:63979 Thu 04 May 2023 09:29:59 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:72250 Thu 02 May 2024 09:21:29 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:50092 Sun 23 Feb 2025 15:20:32 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:28298 Sat 01 Jul 2023 12:28:13 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:45517 Mon 26 Aug 2024 09:37:18 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:28063 90%) sequence similarity between BSCOMT and human soluble COMT (HSCOMT). BSCOMT was partially purified to 7.78 fold, 1.65% yield and had a specific activity of 0.052 U/mg. It had pH and temperature optima of 8.5 and 40oC, respectively. The Km, Vmax, Kcat and Kcat/Km towards esculetin methylation were respectively 1.475±0.130 pM, 0.0353±0.001 pmol/ml/min, 1.748 x 10-2±5.0x10-4 min-1 and 1.18x10-2 M-1. min-1. HSCOMT was expressed in Escherichia coli BL21(DE3) which showed optimal activity for esculetin methylation at pH and temperature of 7.0 and 30°C, respectively. It was purified to 5.62 fold, 22.6% yield with a specific activity of 3.85 U/mg. HSCOMT kinetic plots, upon incubation of the reaction mixture at 30°C for 5 min before addition of SAM was hyperbolic with Km, Vmax, Kcat and Kcat/Km values of 1.79 pM, 0.412 pmol/ml/min, 2.08 min-1 and 1.165 M-1. min-1, respectively. AuNPs and AgNPs showed a concentration dependent inhibition of HSCOMT activity upon increasing the 5 min incubation time to 1 h. Interestingly, HSCOMT kinetics, with 1 h incubation at 30°C, showed a sigmoidal curve, as well as increased activity. Incubation of the reaction mixture in the presence of 60 pM AuNPs and/or AgNPs for 1 hreversed the observed sigmoidal to a hyperbolic curve, with kinetic parameters comparable to those of 5 min incubation. SDS-PAGE analyses of HSCOMT after the kinetic experiments showed the enzyme incubated for 5 min as a monomer, while that which was incubated for 1 h migrated substantially as dimer. However, the HSCOMT incubated for 1 h in the presence of 60 pM AuNPs and/or AgNPs migrated as a monomer. This indicated that the extension of the incubation period allowed the dimerization of HSCOMT, which exhibited sigmoidal kinetics and higher activity. The presence of NPs impeded the HSCOMT dimerization which decreased the activity. Varying the concentration of SAM suggested that SAM had an allosteric modulatory effect on HSCOMT. Absorption spectroscopy indicated adsorption of HSCOMT on the gold and silver NP surfaces and the formation of NPs-HSCOMT corona. Fluorescence spectroscopy showed that the interaction of HSCOMT with both gold and silver NPs was governed by a static quenching mechanism, implying the formation of a non-fluorescent fluorophore-NP complex at the ground state. Further fluorometric analyses indicated that both gold and silver NPs had contact with Trp143; that the interactions were spontaneous and were driven by electrostatic interactions. Fourier transform infrared spectroscopic studies showed the adsorption of HSCOMT of the NPs surfaces to cause relaxation of the enzyme’s B-sheet structures. Molecular docking studies indicated involvement of largely hydrophilic amino acids, with the interacting distances of less than 3.5A. These findings signify the potential of nanotechnology in the control of COMT catalytic activity for the management of the COMT-related disorders.]]> Mon 13 Mar 2023 14:31:23 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:28145 Mon 13 Mar 2023 12:53:24 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:28421 85 % isoniazid released at 24 h, implying that the majority of encapsulated isoniazid would be available for absorption. The manufacturing process resulted in the production of hard spherical particles and particle size analysis revealed that the microspheres ranged between 415.76 ± 76.93 μm and 903.35 ± 197.10 μm in diameter. The microspheres exhibited excellent flow properties attributed to the spherical nature of particles. Carr‟s index (CI) was 4.934 ± 0.775 % and the Hausner ratio (HR) was 1.148 ± 0.033 indicating good packability of the microspheres that would help in achieving weight and content uniformity of capsule dosage units. The manufacturing process however produced a low % yield suggesting that scale up difficulties may be encountered. However the high encapsulation efficiency observed may counter the challenges associated with the low yield. The DSC thermograms and FT Raman spectra of 1:1 mixtures of isoniazid, excipients and the microspheres did not reveal any potential detrimental interactions. Microporous floating sustained release microspheres for the delivery of rifampicin in the stomach have been successfully manufactured using emulsification and a diffusion/evaporation process. A novel approach using solvent mixture of acetone and dichloromethane that has not been reported for the manufacture of rifampicin microspheres was successfully used and resulted in the formation of a stable emulsion and the manufacture of rifampicin-loaded microspheres with uniform characteristics. In addition the manufacturing process was shorter than most other reported methods. A Box-Behnken experimental design was successfully used to study the influence of ethylcellulose, Eudragit® RLPO and d-glucose content on the floating properties, encapsulation efficiency and % yield of microspheres. The optimised formulation did not yield desired floating characteristics as the % buoyancy was low and floating lag times were high. The optimised formulation was modified by addition of NaHCO3 to increase the % buoyancy and reduce the floating lag time. Rifampicin release from the microspheres of the modified batch was 87.10 % at 12 h and the microspheres exhibited a % buoyancy of 87.66 ± 1.28 % (n = 6) and floating lag time of 15 ± 3.2 (n = 6) seconds. The microspheres remained buoyant for up to 12 h and an encapsulation efficiency of 88.26 ± 1.25 % was achieved. SEM images of microspheres following exposure to dissolution fluid revealed that the microspheres had numerous pores on their surface. The mean particle size distribution ranged between 423.19 ± 121.86 μm to 620.07 ± 102.67 μm. The microspheres exhibited similar flow characteristics to isoniazid microspheres with a CI of 1.422 ± 0.074 %, and HR of 1.034 ± 0.002. The excellent flow characteristics indicate that filling of the microspheres into hard gelatin capsules was unlikely to pose a challenge in respect of producing a product with uniform content. Rifampicin-excipient compatibility studies did not reveal any potential or significant interactions suggesting that the excipients used for the manufacture of the microspheres were compatible, although long term stability studies would be required to ascertain this is, indeed the case. The microporous floating sustained release microspheres manufactured in these studies has the potential to increase the bioavailability of rifampicin as they may be retained in the stomach where the solubility of rifampicin is high and from which absorption is best achieved. The degradation of rifampicin after 12 h dissolution testing in pH 1.2 0.1 M HCl in the presence of isoniazid gastric-resistant sustained release microspheres was only 4.44%. These results indicate that the degradation of rifampicin in the presence of isoniazid in acidic media can be overcome by encapsulation of both active pharmaceutical ingredients in a manner that ensure release in different segments of the gastrointestinal tract. The use of sustained release microporous gastroretentive rifampicin microspheres in combination with sustained release isoniazid gastric-resistant microspheres revealed that accelerated degradation of rifampicin in the presence of isoniazid is reduced significantly when using this approach and a FDC of rifampicin and isoniazid microspheres has the potential to improve the bioavailability of rifampicin thereby enhancing therapeutic outcomes. In vivo studies would be required to confirm the potential benefits of using this approach to deliver rifampicin in combination with isoniazid.]]> Mon 13 Mar 2023 11:57:13 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:28347 Mon 11 Nov 2024 08:54:54 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:44576 Mon 06 May 2024 15:40:44 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:44578 Mon 06 May 2024 15:39:22 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:77681 Mon 03 Mar 2025 08:55:43 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:74962 Fri 30 Aug 2024 03:56:51 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:72092 Fri 26 Apr 2024 09:59:52 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:72114 Fri 26 Apr 2024 09:59:00 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:72089 Fri 26 Apr 2024 09:57:37 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:43191 Fri 25 Apr 2025 09:24:07 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:43799 Fri 25 Apr 2025 09:16:49 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:69400 Fri 25 Apr 2025 09:16:44 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:74225 Fri 12 Jul 2024 13:13:22 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:69403 Fri 10 May 2024 14:48:44 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:71346 Fri 10 May 2024 14:37:50 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:69385 Fri 10 May 2024 07:46:46 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:28130 Fri 10 Mar 2023 15:27:16 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:28297 Fri 10 Mar 2023 12:46:15 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:45423 Fri 10 Mar 2023 10:05:17 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:68724 Fri 06 Oct 2023 12:59:55 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:68723 Fri 06 Oct 2023 12:56:49 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:78471 Fri 02 May 2025 15:22:08 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:74590 Fri 02 Aug 2024 16:30:15 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:74593 Fri 02 Aug 2024 16:30:14 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:74578 Fri 02 Aug 2024 16:30:14 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:74592 Fri 02 Aug 2024 16:30:11 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:74579 Fri 02 Aug 2024 16:30:10 SAST ]]>