http://vital.seals.ac.za:8080/vital/access/manager/Index ${session.getAttribute("locale")} 5 http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:4375 Wed 12 May 2021 23:20:49 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:4332 Wed 12 May 2021 20:25:51 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:4285 Wed 12 May 2021 19:56:19 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:29116 Wed 12 May 2021 19:14:06 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:4538 Wed 12 May 2021 19:02:23 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:4548 Wed 12 May 2021 18:32:45 SAST ]]> http://vital.seals.ac.za:8080/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 ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:41377 Wed 12 May 2021 14:34:09 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:4553 600 nm) in dimethylsulphoxide solution. All the ligands were transformed into the dihydroxy silicon octaphenoxyphthalocyanine with varying degrees of phototransformation quantum yields ranging in order from 10⁻³ to 10⁻⁵ depending on the axial ligand involved. During and after axial ligand transformations a photodegredation of the dihydroxy silicon octaphenoxy phthalocyanine was observed upon continued irradiation. The oligomers were found to undergo the same axial ligand transformation process with a phototransformation quantum yield of 10⁻⁵ The singlet oxygen quantum yields of the unaggregated monomeric silicon octaphenoxy phthalocyanines were all found to be approximately 0.2 with the exception of a compound with two (trihexyl)siloxy axial substituents that had a singlet oxygen quantum yield of approximately 0.4 in dimethylsulphoxide solutions. The oligomers showed a surprising trend of an increase in singlet oxygen quantum yield with an increase in phthalocyanine ring number up to the pentamer and then a dramatic decrease to the nonamer. The triplet quantum yield and triplet lifetime were determined by laser flash photolysis for selected compounds and no correlation was observed with any of these properties and the singlet oxygen quantum yields. These selected compounds all fluoresce and a very good correlation was found between the fluorescence lifetimes determined experimentally by laser photolysis and the Strickler-Berg equation for the non-aggregated compounds. Electrochemical measurements also indicate the importance of the axial ligands upon the behaviour of the phthalocyanines as cyclic voltammetric behaviour was determined by the nature of the axial ligand.]]> Thu 13 May 2021 14:52:35 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:35406 Thu 13 May 2021 06:50:34 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:4539 Thu 13 May 2021 04:42:43 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:4374 Thu 13 May 2021 03:57:29 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:4544 Thu 13 May 2021 03:36:01 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:4291 Thu 13 May 2021 01:46:25 SAST ]]> http://vital.seals.ac.za:8080/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 ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:57238 Mon 24 Oct 2022 15:47:54 SAST ]]> http://vital.seals.ac.za:8080/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 ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:65804 S0 excitation energies. The small deviation observed between the calculated and experimental spectra arises from the solvent effect. The excitation energies observed in these UV-Vis spectra mostly originated from electron promotion between the highest occupied molecular orbital (HOMO) for the less intense band and the HOMO-1 for the most intense band of the ground states to the lower unoccupied molecular orbital (LUMO) of the excited states.]]> Fri 17 May 2024 16:29:44 SAST ]]>