https://commons.ru.ac.za/vital/access/manager/Index ${session.getAttribute("locale")} 5 https://commons.ru.ac.za/vital/access/manager/Repository/vital:55699 Wed 31 Aug 2022 14:53:49 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:55696 Wed 31 Aug 2022 14:48:36 SAST ]]> 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:43872 Wed 24 Apr 2024 13:35:02 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:50090 Wed 20 Apr 2022 14:10:00 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:50088 Wed 20 Apr 2022 13:48:55 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:50086 Wed 20 Apr 2022 13:28:53 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:50079 Wed 20 Apr 2022 12:39:49 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:44734 Wed 10 Aug 2022 06:57:14 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:50073 Wed 10 Aug 2022 05:39:17 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:69403 Wed 01 Nov 2023 13:05:09 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:69400 Wed 01 Nov 2023 12:43:43 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:69399 Wed 01 Nov 2023 12:38:47 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:44684 Tue 24 May 2022 15:26:37 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:50092 Tue 18 Jul 2023 22:13:00 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:51101 Tue 17 May 2022 20:41:49 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:28347 Tue 14 Mar 2023 10:19:10 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:44711 Tue 12 Oct 2021 10:39:40 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:44709 Tue 12 Oct 2021 10:30:44 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:44708 Tue 12 Oct 2021 10:18:27 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:68717 Tue 10 Oct 2023 09:23:15 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:50567 Tue 03 May 2022 10:33:56 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:50563 Tue 03 May 2022 10:22:28 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:71346 Thu 25 Jan 2024 13:24:48 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:71345 Thu 25 Jan 2024 13:19:52 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:45521 50 % was often observed. Except for compound 9o, none of the final compounds exhibited cytotoxic effects against HeLa cells at 20 µM.]]> Thu 20 Jul 2023 11:15:00 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:44578 Thu 20 Jul 2023 10:40:01 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:69151 Thu 19 Oct 2023 11:36:58 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:44736 Thu 14 Oct 2021 10:23:23 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:44735 Thu 14 Oct 2021 10:11:27 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:50083 CoTPrOPhOPc > Mn(OAc)TPrOPhOPc. The values βeff (×10−5 m MW−1) using 532 nm Nd:YAG (560 nm monochromatic Ekspla) laser sources were 23.5 > 14.3 > 9.20 (14.4). The second-order nonlinear coefficient obtained using density functional theory calculations, the theoretical hyper-Rayleigh scattering (βHRS, ×10−28 esu), showed the decreasing trend for H2TPrOPhOPc (2.28) > CoTPrOPhOPc (2.10) > Mn(OAc)TPrOPhOPc (1.86). The 4-(propargyloxy)phenoxy substituents enhanced the optical limiting properties of the synthesized phthalocyanines.]]> Thu 11 Aug 2022 12:39:51 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:50556 Thu 11 Aug 2022 12:39:00 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:44695 Thu 11 Aug 2022 12:37:38 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:50206 Thu 11 Aug 2022 12:36:41 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: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:28533 Thu 09 Mar 2023 09:44:15 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:51987 Thu 09 Jun 2022 15:43:09 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:45517 Sun 12 Dec 2021 15:35:24 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:44714 Sat 04 Dec 2021 12:22:30 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:44713 Sat 04 Dec 2021 12:21:58 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:44725 Sat 04 Dec 2021 12:21:07 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:44682 Sat 04 Dec 2021 12:20:21 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:44730 Sat 04 Dec 2021 12:19:30 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:44704 Mon 13 Nov 2023 20:10:31 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:50203 Mon 13 Nov 2023 20:09:27 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:50195 Mon 13 Nov 2023 20:08:26 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:50196 Mon 13 Nov 2023 20:07:35 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:44700 Mon 13 Nov 2023 20:06:37 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:50087 Mon 13 Nov 2023 20:05:36 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:43799 Mon 08 Aug 2022 09:12:14 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:43189 Mon 08 Aug 2022 06:38:38 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:43190 Mon 08 Aug 2022 06:35:38 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:43191 Mon 08 Aug 2022 06:33:43 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:43178 Mon 08 Aug 2022 06:32:15 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:43910 Mon 08 Aug 2022 06:29:45 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:43354 Mon 08 Aug 2022 06:27:56 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:43192 Mon 08 Aug 2022 06:25:27 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:43359 Mon 08 Aug 2022 06:24:01 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:43353 Mon 08 Aug 2022 06:20:52 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:43727 Mon 08 Aug 2022 06:19:08 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:43179 Mon 08 Aug 2022 06:17:53 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:43193 Mon 08 Aug 2022 05:52:29 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:43351 Mon 08 Aug 2022 05:46:20 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:68301 Fri 29 Sep 2023 09:08:59 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:70334 Fri 26 Apr 2024 11:03:15 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:71460 Fri 26 Apr 2024 11:02:45 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:72051 Fri 26 Apr 2024 11:02:06 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:71635 Fri 26 Apr 2024 10:00:39 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:50213 Fri 22 Apr 2022 13:26:50 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:50209 Fri 22 Apr 2022 12:48:59 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:50205 Fri 22 Apr 2022 12:20:45 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:44727 Fri 15 Oct 2021 09:06:59 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:69385 Fri 09 Feb 2024 16:01:58 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:49235 Fri 01 Apr 2022 11:06:01 SAST ]]>