https://vital.seals.ac.za/vital/access/manager/Index ${session.getAttribute("locale")} 5 https://vital.seals.ac.za/vital/access/manager/Repository/vital:65765 Wed 19 Jul 2023 10:05:25 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:28690 Wed 19 Apr 2023 13:28:11 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4380 Wed 12 May 2021 23:59:48 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4440 Wed 12 May 2021 23:34:27 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4375 Wed 12 May 2021 23:20:49 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4389 Wed 12 May 2021 23:17:08 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:30590 Wed 12 May 2021 23:10:41 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4530 Wed 12 May 2021 23:10:09 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4502 Wed 12 May 2021 23:07:26 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4373 Wed 12 May 2021 22:40:49 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4516 Wed 12 May 2021 22:38:38 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4388 Wed 12 May 2021 22:23:26 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4378 Wed 12 May 2021 20:56:27 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4346 Wed 12 May 2021 20:52:33 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4371 Wed 12 May 2021 20:52:26 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:34016 Wed 12 May 2021 20:49:16 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4392 Wed 12 May 2021 20:24:11 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4463 Wed 12 May 2021 20:04:16 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4510 Wed 12 May 2021 20:01:22 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:20352 Wed 12 May 2021 20:00:59 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4512 Wed 12 May 2021 19:40:46 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4319 Wed 12 May 2021 19:35:53 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:24712 Wed 12 May 2021 19:31:47 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4495 Wed 12 May 2021 19:27:09 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4559 Wed 12 May 2021 19:26:07 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4376 Wed 12 May 2021 19:11:10 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4393 Wed 12 May 2021 18:30:26 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:38373 Wed 12 May 2021 18:28:38 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:20807 Wed 12 May 2021 17:46:03 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4339 Wed 12 May 2021 17:44:25 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4452 Wed 12 May 2021 17:34:47 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4381 Wed 12 May 2021 17:29:40 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4331 Wed 12 May 2021 17:29:37 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4379 Wed 12 May 2021 17:27:55 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4562 Co(II) > Ni(II). The Schiff-base derivatives were prepared from the ligands and para-methoxysalicylaldehyde and their Cu(II) complexes were synthesized in order to determine their biological activity. The Schiff-base ligands were found to be less active than their parent ligands. The Cu(II) complexes are not soluble in water, DMSO or DMF, as a result and could not be evaluated for their biological activity. Based on the good results from the antimicrobial evaluation, the antiplasmodial activity of some of the Co(II), Ni(II) and Cu(II) complexes of the thiomethylated ligands against Plasmodium falciparum (FCR-3) was determined. At 50 μM concentration level, the Cu(II) complexes show activity equal or better than the prophylactic chloroquine. The Cu(II) complexes with the methoxy-substituted demonstrated exceptional activity but their Co(II) and Ni(II) analogues did not show any activity. The cytotoxicity of the active Cu(II) complexes at 50 μM concentration was determined against the breast cancer cell line (MDA-MB-231). The compounds destroyed the cancer cell in the range of 28–40%, thus showing their preferred activity against the parasitic cell instead of the cancer cell. The selectivity demonstrated by these compounds have shown them to be potential antimalarial agents and this could be further investigated.]]> Wed 12 May 2021 17:24:20 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4483 Wed 12 May 2021 17:15:09 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4298 Wed 12 May 2021 17:10:11 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:4503 Wed 12 May 2021 16:39:07 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4453 Wed 12 May 2021 16:31:51 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4534 Wed 12 May 2021 16:27:58 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4289 Wed 12 May 2021 16:26:21 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:21169 Wed 12 May 2021 16:24:12 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:31232 Wed 12 May 2021 16:19:18 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4304 Wed 12 May 2021 16:08:21 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:42174 Wed 12 May 2021 15:00:21 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:41489 50% cell viability) at concentrations ≤100 μg/mL, however the conjugates showed < 45% cell viability at concentrations ≤ 100 μg/mL, probably due to the small micellar size and EPR effect. The findings from this work show the importance of incorporating photosensitizers such as phthalocyanines into Pluronic polymers micelles and making them water soluble and ultimately improving their photodynamic effect.]]> Wed 12 May 2021 14:58:28 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:41495 Wed 12 May 2021 14:08:47 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:42108 3.76 × 10 − 10 ( 4a ) > 3.52 × 10 − 10 ( 4c ) > 2.29 × 10 − 10 ( 3c ) > 1.68 × 10 − 10 ( 3a ) > 1.65 × 10 − 10 ( 3b ) mW - 1 . The 휷 values trend of synthesized Pc complexes show that the asymmetrical A 3 B type metal free, cobalt and zinc Pc complexes ( 4a , 4b and 4c ) have larger 휷 values as compared to the octa - substituted symmetrical metal free, cobalt and zinc Pc complexes ( 3a , 3b and 3c ) which is attributed to the low symmetry of the Pc complexes. The five - level model rate equations were used to determine the two photon absorption, excited state absorption and ground state absorption cross sections of the synthesized complexes. The z inc A 3 B type asymmetrical Pc complexes gave the largest two photon absorption and 휎 푒 / 휎 푔 ratio values. This Pc complex could be used in future work to enhance the nonlinear response further by introducing nanomaterials and converting the Pc complex to a binuclear Pc. This work also reports on the density functional theory (DFT) calculations o f dipolar/octupolar contributions in order to study the first order hyperpolarizability of the synthesized Pc complexes.]]> Wed 12 May 2021 13:45:11 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:65793 Wed 10 Jan 2024 11:15:28 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:45271 Tue 16 Nov 2021 09:28:07 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:56795 Thu 22 Sep 2022 11:14:34 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:28695 CoTPrOPhOPc > MnTPrOPhOPc. According to the trend observed, the H2TPrOPhOPc was an excellent nonlinear optical limiter when compared to the CoTPrOPhOPc and MnTPrOPhOPc. All the investigated complexes exhibited optical limiting properties comparable to the phthalocyanine complexes reported in the literature. The MTPrOPhOPc complexes were further studied for their electrocatalytic and electroanalytical properties towards the detection of hydrogen peroxide. For the electrocatalytic studies, the synthesized complexes were immobilized onto gold electrode surfaces pre-functionalized with phenylazide (Au-PAz) monolayer. Copper (I) catalyzed alkynyl-azide cycloaddition reaction was used to covalently immobilize the MTPrOPhOPcs onto the gold electrode surfaces to form Au-PAz-MTPrOPhOPc. The MTPrOPhOPcs modified gold surfaces (Au-PAz-MTPrOPhOPc) exhibited good reproducibility and stability in various electrolyte conditions. Electrochemical and surface characterisation of the functionalised gold electrode surfaces confirmed the presence of the MTPrOPhOPcs and their electroanalysis was excellent towards electrocatalytic reduction of H2O2, with the limit of detection (LoD) and limit of quantification (LoQ) in the ^M range. The electrocatalytic reduction peaks for H2O2 were observed at -0.37 V for Au-PAz-MnTPrOPhOPc and -0.31 V for Au-PAz-CoTPrOPhOPc when Ag|AgCl pseudo-reference electrode was used. The Au-PAz-MnTPrOPhOPc and Au- PAz-CoTPrOPhOPc gold electrode surfaces showed good sensitivity and reproducibility towards the electrocatalytic reduction of hydrogen peroxide in pH 7.4 phosphate buffer solution.]]> Thu 20 Apr 2023 09:37:14 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4384 Thu 13 May 2021 14:13:15 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4469 Thu 13 May 2021 13:43:18 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4377 Thu 13 May 2021 10:50:32 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4560 Thu 13 May 2021 08:53:23 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4488 Thu 13 May 2021 08:45:53 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:31075 Thu 13 May 2021 08:45:50 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4287 0.99. In the column experiment the highest loading capacity of Pt and Pd were 7.4 mg/g and 4.3 mg/g respectively on the nanofiber sorbent material based on ethylenediamine (EDA). The polystyrene and silica-based resins with triethylenetetramine (TETA) functionality (M-TETA and S-TETA) showed selectivity for platinum and palladium, respectively. Metal chlorido complexes loaded on the sorbent materials were recovered by using 3% m/v thiourea solution as teh eluting agent with quantitative desorption efficiency under the selected experimental conditions. The separation of platinum from palladium was partially achieved by selective stripping of PtCl₆²⁻ with 0.5 M of NaClO₄ in 1.0 M HCI with PdCl₄²⁻ was eluted with 0.5 M thiourea in 1.0 M HCI. The selectivity of the M-TETA and S-TETA sorbent materials was proved by column separation of platinum(IV) and palladium(II), respectively, from synthetic solutions containing iridium(IV) and rhodium(III). The loading capacity for platinum on M-TETA was 0.09 mg/g while it was 0.27 mg/g for palladium on S-TETA.]]> Thu 13 May 2021 07:36:09 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4484 Thu 13 May 2021 07:36:08 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:21132 Thu 13 May 2021 07:18:55 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4480 Thu 13 May 2021 07:14:16 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4290 Thu 13 May 2021 07:12:37 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4305 Thu 13 May 2021 07:09:37 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4507 Thu 13 May 2021 07:07:10 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4296 Thu 13 May 2021 06:58:59 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4385 Thu 13 May 2021 06:58:04 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:20969 Thu 13 May 2021 06:25:14 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4386 Thu 13 May 2021 06:22:18 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:19967 Thu 13 May 2021 06:21:13 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4428 Thu 13 May 2021 06:10:53 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4485 Thu 13 May 2021 05:54:35 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4491 Thu 13 May 2021 05:16:31 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4390 Thu 13 May 2021 05:13:42 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4525 Thu 13 May 2021 04:54:01 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4382 Thu 13 May 2021 04:50:07 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4374 Thu 13 May 2021 03:57:29 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:4518 Thu 13 May 2021 03:22:47 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4301 Thu 13 May 2021 03:21:05 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4564 Thu 13 May 2021 03:19:45 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4478 Thu 13 May 2021 02:45:06 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4387 Thu 13 May 2021 02:35:39 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4531 Thu 13 May 2021 02:12:38 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4438 Thu 13 May 2021 01:41:54 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4467 Thu 13 May 2021 01:14:12 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:34528 Thu 13 May 2021 00:32:13 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4436 67 > 66. Comparing porphyrazine complexes (63, 64 and 65), 63 with benzene attached to the ring, has higher triplet state lifetime (420 μs) compared to 64 and 65 containing long alkyl chain and tertbutyl substituents, 350 and 360 μs,respectively). The observed Φ[subscript]f values for 68 and 63 were quiet suprising, since low values are observed compared to the rest of the complexes (e.g 0.03 and 0.02 respectively). Although these values seem so low, they are sufficient for fluorescence imaging applications. The Φ[subscript]f values for the complexes under study are within the range reported for complexes currently used for PDT.]]> Thu 13 May 2021 00:21:54 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4476 Thu 13 May 2021 00:15:01 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4522 Thu 13 May 2021 00:07:45 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4492 Thu 13 May 2021 00:06:57 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:27456 Thu 13 Apr 2023 09:16:21 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:72158 Sat 20 Apr 2024 18:01:54 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:71958 Sat 06 Apr 2024 13:48:43 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:44750 22% cell viability at concentrations ≤ 50 μg/mL relative to conjugates with <22% cell viability at concentrations ≤ 50 μg/mL. There was no direct relationship between PDT and singlet oxygen quantum yields. Nonlinear optical characteristics of complexes was improved upon conjugation of DNDs. Absorbance, input energy, percentage loading, central metal, substituent of Pc and nature of interaction (covalent, noncovalent) are amongst some of the factors that influence nonlinear absorption properties of materials used in this study. All materials followed reverse saturable absorption through two photon absorption mechanism at the excitation wavelength of 532 nm. Aggregates reduce excited state lifetime and Beff under high concentrations/absorbance. A direct relationship between absorbance and Beff of DNDs nanoconjugated systems at low concentrations result in increased optical limiting characteristics of materials. The findings from this work show the importance of linking (nonlinear optics and photodynamic therapy) and doping (photodynamic therapy) photosensitisers such as phthalocyanines and sometimes boron dipyrromethenes onto carbon based nanoparticles for the enhanced characteristics in variable applications.]]> Mon 15 Nov 2021 16:13:10 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:50035 Mon 10 Oct 2022 08:41:01 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:35604 Fri 31 Mar 2023 12:24:50 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:44791 Fri 22 Oct 2021 15:54:57 SAST ]]>