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Speaking at Union Meetings

- Irish Congress of Trade Unions (ICTU)

Authors: Irish Congress of Trade Unions (ICTU)
Subjects: ICTU
Language: English
Type: text
Identifier: http://hdl.handle.net/10962/174145 , vital:42446
Description: The type of meetings we have in mind are general members’ meetings with more than ten people in attendance. These notes are relevant where you have an opportunity to think beforehand about what you are going to say and to spend some time on preparation. Sometimes you may have to speak 'on the spur of the moment' in response to information, a statement or an event. In these circumstances, you should try to get your thoughts together before you speak, rather than simply 'thinking out loud’. The most important point about the 'spur of the moment' type of situation is to say what’s on your mind. Don’t leave it to someone else. These ‘spontaneous’ contributions to meetings can be very effective. People usually can recognise when someone is speaking ‘from the heart’! Sincerity, honesty and conviction are much more important for effective speaking than ‘polish’ and presentation. Hundreds of books have been written and millions of pounds ’earned’ telling people how to get their message across. While good presentation can help, for the trade union movement what people say is more important than how they say it. A speech is effective if the audience remembers most of the points made by the speaker.
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Spectral properties and photophysical behaviour of water soluble cationic Mg(II) and Al(III) phthalocyanines

- Idowu, Mopelola A, Arslanoglu, Yasin, Nyokong, Tebello

Authors: Idowu, Mopelola A , Arslanoglu, Yasin , Nyokong, Tebello
Language: English
Type: Article
Identifier: vital:7277 , http://hdl.handle.net/10962/d1020292
Description: Peripherally and non-peripherally tetrasubstituted-[(N-methyl-2-pyridylthio)]phthalocyaninato magnesium (II) (5 and 6) and chloro aluminium (III) (7 and 8) tetraiodide have been synthesized and characterized. The photophysical properties of the complexes in dimethyl sulfoxide (DMSO) and aqueous medium in the presence and absence of cremophore EL have been studied. These complexes show high solubility in aqueous medium though they were aggregated. The triplet state quantum yields (FT) and the triplet lifetimes (tT) were found to be higher in DMSO with ΦT ranging from 0.32 to 0.51, while tT ranged from 282 to 622 ms in DMSO, compared to aqueous medium (pH 7.4 buffer) where ΦT ranged from 0.15 to 0.19 and tT from 26 to 35 ms. Addition of cremophore EL in aqueous solution resulted in partial disaggregation and increased photoactivity. The fluorescence lifetimes of the complexes showed strong dependence on their immediate environment. The ionic magnesium(II) and aluminium(III) phthalocyanines strongly bind to bovine serum albumin (BSA). , Original publication is available at http://dx.doi.org/10.2478/s11532-013-0388-z
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Surface modification of silica-coated gadolinium oxide nanoparticles with zinc tetracarboxyphenoxy phthalocyanine for the photodegradation of Orange G

- Ledwaba, Mpho, Masilela, Nkosiphile, Nyokong, Tebello, Antunes, Edith M

Authors: Ledwaba, Mpho , Masilela, Nkosiphile , Nyokong, Tebello , Antunes, Edith M
Language: English
Type: Article
Identifier: vital:7249 , http://hdl.handle.net/10962/d1020255
Description: Zinc tetracarboxyphenoxy phthalocyanine was covalently linked to Gd2O3 nanoparticles for the photocatalytic degradation of Orange G. Characterization of the composite was carried out using XRD, TEM, XPS, UV–vis spectroscopy and FT-IR spectroscopy. The composite showed improved photophysical properties over the phthalocyanine alone and the catalyst was found to be reusable. Analyses of the photodegradation rates of the azo dye indicated pseudo first-order kinetics. , Original publication is available at http://dx.doi.org/10.1016/j.molcata.2015.03.023
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Surface patterning using scanning electrochemical microscopy to locally trigger a “click” chemistry reaction

- Quinton, Damien, Maringa, Audacity, Griveau, Sophie, Nyokong, Tebello, Bedioui, Fethi

Authors: Quinton, Damien , Maringa, Audacity , Griveau, Sophie , Nyokong, Tebello , Bedioui, Fethi
Language: English
Type: Article
Identifier: vital:7331 , http://hdl.handle.net/10962/d1020592
Description: We report on the surface micropatterning of conductive surfaces via the electrochemical triggering of a click reaction, the copper(I) catalyzed azide–alkyne cycloaddition reaction (CuAAC) by SECM via a two-step approach: (i) functionalization on the entire surface with azido-aryl groups by using the diazonium approach followed by (ii) the covalent linkage of alkyne-bearing ferrocene by CuAAC within a local area by SECM. More precisely, the click reaction was triggered by Cu(I) catalyst generation for 30 min at the SECM tip positioned ≈ 10 μm above the azido-aryl modified surface. The dimension of the spot obtained under these conditions was ≈ 75 μm. The electrochemical imaging by SECM of the ultra thin area locally clicked with ferrocene moieties was made thanks to the electrocatalytic properties of the ferrocene modified surface towards ferrocyanide electrooxidation. This local clicking procedure opens the gate to further controlled functionalization of restricted small substrates. , Original publication is available at http://dx.doi.org/10.1016/j.elecom.2013.03.021
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Synthesis and characterization of Na(Y,Gd)F4 upconversion nanoparticles and an investigation of their effects on the photophysical properties of an unsubstituted tetrathiophenoxy phthalocyanine

- Taylor, Jessica M, Litwinski, Christian, Nyokong, Tebello, Antunes, Edith M

Authors: Taylor, Jessica M , Litwinski, Christian , Nyokong, Tebello , Antunes, Edith M
Language: English
Type: Article
Identifier: vital:7253 , http://hdl.handle.net/10962/d1020261
Description: Sphere- and star-shaped Na(Y,Gd)F4:Yb/Er(Tm)upconversion nanoparticles (UCNP) were successfully synthesized utilizing a methanol-assisted thermal decomposition approach and their spectroscopic (absorption, emission and luminescence lifetime) properties fully characterized. The factors affecting the size and shape of the UCNPs were studied and discussed in detail. The size of the nanoparticles was determined using TEM primarily and found to be approximately 19 and 30 nm for the Er and Tm spheres, respectively, while the Er and Tm “stars” were found to be much larger with sizes ranging from 110 to 240 nm, respectively (as determined along the width of the nanoparticle). In addition, their influence on the spectroscopic properties of an unsubstituted tetrathiophenoxy phthalocyanine (H2Pc) was investigated. The UCNP were found to produce characteristic upconversion luminescence emissions in the blue, green, red and NIR regions. Simple mixing with an H2Pc in toluene was found to exert no obvious changes in the spectroscopic properties of the Pc, although a considerable increase in the radiative lifetimes is observed for the Pc in the presence of the UCNPs. The singlet oxygen generation mediated by the red light excitation of the H2Pc mixed with UCNP was found to decrease in the presence of the NPs. , Original publication is available at http://dx.doi.org/10.1007/s11051-015-2889-5
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Synthesis and characterization of quantum dots designed for biomedical use

- Kuzyniak, Weronika, Adegoke, Oluwasesan, Sekhosana, Kutloano, D’Souza, Sarah, Tshangana, Sesethu Charmaine, Hoffmann, Björn, Ermilov, Eugeny A., Nyokong, Tebello, Höpfner, Michael

Authors: Kuzyniak, Weronika , Adegoke, Oluwasesan , Sekhosana, Kutloano , D’Souza, Sarah , Tshangana, Sesethu Charmaine , Hoffmann, Björn , Ermilov, Eugeny A. , Nyokong, Tebello , Höpfner, Michael
Language: English
Type: Article
Identifier: vital:7310 , http://hdl.handle.net/10962/d1020387
Description: Semiconductor quantum dots (QDs) have become promising nanoparticles for a wide variety of biomedical applications. However, the major drawback of QDs is their potential toxicity. Here, we determined possible cytotoxic effects of a set of QDs by systematic photophysical evaluation in vitro as well as in vivo. QDs were synthesized by the hydrothermal aqueous route with sizes in the range of 2.0–3.5 nm. Cytotoxic effects of QDs were studied in the human pancreatic carcinoid cell line BON. Cadmium telluride QDs with or without zinc sulfide shell and coated with 3-mercaptopropionic acid (MPA) were highly cytotoxic even at nanomolar concentrations. Capping with l-glutathione (GSH) or thioglycolic acid (TGA) reduced the cytotoxicity of cadmium telluride QDs and cadmium selenide QDs. Determination of the toxicity of QDs revealed IC50 values in the micromolar range. In vivo studies showed good tolerability of CdSe QDs with ZnS shell and GSH capping. We could demonstrate that QDs with ZnS shell and GSH capping exhibit low toxicity and good tolerability in cell models and living organisms. These QDs appear to be promising candidates for biomedical applications such as drug delivery for enhanced chemotherapy or targeted delivery of light sensitive substances for photodynamic therapy. , Original publication is available at http://dx.doi.org/10.1016/j.ijpharm.2014.03.037
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Synthesis and electrochemical properties of new cobalt and manganese phthalocyanine complexes tetra-substituted with 3,4-(methylendioxy)-phenoxy

- Erdoğmuş, Ali, Akinbulu, Isaac Adebayo, Nyokong, Tebello

Authors: Erdoğmuş, Ali , Akinbulu, Isaac Adebayo , Nyokong, Tebello
Language: English
Type: Article
Identifier: vital:7234 , http://hdl.handle.net/10962/d1019672
Description: The synthesis and electrochemical properties of new cobalt and manganese phthalocyanine complexes, tetra-substituted with 3,4-(methylendioxy)-phenoxy at the peripheral (complexes 3 and 5) and non-peripheral (complexes 4 and 6) positions, are reported. Complexes 3 and 4 showed Q-band absorption, in DMF, at 668 and 686 nm, respectively while Q-band due to complexes 5 and 6 appeared at 732 and 760 nm, respectively in CHCl3. All the complexes showed well resolved redox processes attributed to both metal and ring based processes. Complexes 3 and 4 showed four redox processes, labeled I, II, III and IV. For complex 3, process I (CoIPc−2/CoIPc−3) was observed at −1.45 V, II (CoIIPc−2/CoIPc−2) at −0.38 V, III (CoIIIPc−2/CoIIPc−2) at +0.49 V and IV (CoIIIPc−1/CoIIIPc−2) at +0.97 V versus Ag|AgCl. Similar processes were observed for complex 4 at −1.36 V, −0.27 V, +0.56 V, +1.03 V versus Ag|AgCl, respectively. Complexes 5 and 6 showed two redox processes (I and II). For complex 5, these processes appeared at −0.79 V (MnIIPc−2/MnIIPc−3, I) and −0.07 V versus Ag|AgCl (MnIIIPc−2/MnIIPc−2, II), while for complex 6, they were observed at −0.86 V and −0.04 V versus Ag|AgCl. Spectroelectrochemistry was used to probe and confirm the origin of these processes. , Original publication is availabe at http://dx.doi.org/10.1016/j.poly.2010.05.012
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Synthesis of zinc phthalocyanine derivatives with improved photophysicochemical properties in aqueous media

- Erdoğmuş, Ali, Nyokong, Tebello

Authors: Erdoğmuş, Ali , Nyokong, Tebello
Language: English
Type: Article
Identifier: vital:7236 , http://hdl.handle.net/10962/d1019687
Description: The synthesis, photophysical and photochemical properties of new peripherally (β) tetra-substituted thioquinoline Zn(II) (2) and quaternized thioquinoline Zn(II) phthalocyanines (3) and quaternized fluoro functional thiopyridine Zn(II) (5) are described for the first time. These complexes (2, 3 and 5) have been synthesized and characterized by elemental analysis, IR, 1H NMR spectroscopy and electronic spectroscopy. Complexes 2, 4 and 6have good solubility in organic solvents such as CHCl3, DCM, DMSO, DMF, THF and toluene and are not aggregated in all solvents (except for 2 in DMSO) within a wide concentration range. Complexes 3 and 5 showed very good solubility in water as well as DMSO and DMF. General trends are described for singlet oxygen, photodegradation, fluorescence quantum yields, triplet quantum yields and triplet life times of these complexes in DMSO (2, 4 and 6) and water (3 and 5). Complex 3 gave a very large triplet quantum yield in aqueous media (ΦT = 0.8 in water plus Triton X-100) and a reasonable triplet lifetime of 110 μs. Photophysical and photochemical properties of the phthalocyanines complexes 2–6 are very useful for PDT. , Original publication is available at http://dx.doi.org/10.1016/j.molstruc.2010.04.048
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Synthesis, characterization and photophysical properties of an acenaphthalene fused-ring-expanded NIR absorbing aza-BODIPY dye

- Majumdar, Poulomi, Mack, John, Nyokong, Tebello

Authors: Majumdar, Poulomi , Mack, John , Nyokong, Tebello
Language: English
Type: Article
Identifier: vital:7283 , http://hdl.handle.net/10962/d1020328
Description: The synthesis and characterization of an NIR absorbing acenaphthalene fused-ring-expanded aza-BODIPY dye are reported. In contrast with its naphtho-fused analogue, a stable complex is obtained when the corresponding phthalonitrile is used as the precursor. A comparison is made with the photophysical properties of 3,5-diphenyl-aza-dibenzoBODIPY. , Original publication is available at http://dx.doi.org/10.1039/C5RA14916A , Arbortext Advanced Print Publisher 9.1.510/W Unicode , Acrobat Distiller 8.1.0 (Windows); modified using iText� 5.3.3 �2000-2012 1T3XT BVBA (AGPL-version)
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Synthesis, photophysical and nonlinear optical behavior of neodymium based trisphthalocyanine

- Sekhosana, Kutloano E, Amuhaya, Edith K, Khene, M Samson, Nyokong, Tebello

Authors: Sekhosana, Kutloano E , Amuhaya, Edith K , Khene, M Samson , Nyokong, Tebello
Language: English
Type: Article
Identifier: vital:7243 , http://hdl.handle.net/10962/d1020247
Description: Tris-{1(4),8(11),15(18),22(25)-tetra(4-tertbutylphenoxy) phthalocyaninato} dineodymium (III) was synthesised and its nonlinear optical and fluorescence behavior was studied. Low fluorescence quantum yield (ФF = 0.03) was obtained with a fluorescence lifetime τF = 4.31 ns for this complex. Nonlinear optical parameters for the complex were determined using the Z-scan technique and the values of Im[χ(3)] and γ were of the order of 10−10 and 10−28 esu, respectively. Square wave voltammetry revealed three reduction and two oxidation couples for the complex. , Original publication is available at http://dx.doi.org/10.1016/j.ica.2014.11.029
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