Este trabalho teve como objetivo estudar e caracterizar filmes de nanocompósitos de polipirrol dopado com índigo carmim e dodecilsulfato combinados com nanopartículas de ouro para aplicação como biossensores eletroquímicos de pesticida. Primeiramente sintetizou-se três filmes a 10 e 25 ºC por voltametria cíclica: polipirrol dopado com índigo carmim (PPi-IC), polipirrol dopado com índigo carmim contendo nanopartículas de ouro (PPi-IC-NPAu) e polipirrol dopado com índigo carmim e dodecilsulfato de sódio, contendo nanopartículas de ouro (PPi-IC-DS-NPAu). Nesses filmes foram realizadas caracterizações estruturais, morfológicas, ópticas e eletroquímicas, utilizando espectroscopia no infravermelho, espectroscopia Raman, microscopia eletrônica de varredura, espectroscopia UV-VIS-NIR e voltametria cíclica. Os filmes sintetizados a 10 ºC foram modificados com a enzima acetilcolinesterase (AChE), sendo posteriormente caracterizados por microscopia eletrônica de varredura, espectroscopia Raman e voltametria cíclica. Os resultados obtidos mostraram que a interação da enzima com os filmes de polipirrol é dependente de sua composição. A presença de DS não favoreceu a sua imobilização, sendo assim, os filmes de PPi-IC e PPi-IC-NPAu foram os materiais mais adequados para a imobilização física da AChE, sendo capazes de detectar o pesticida metil paration (MP) através da porcentagem de pesticida inibido pela ação da AChE em relação ao cloreto de acetiltiocolina (ATCl). Essa detecção foi realizada por voltametria cíclica, onde a resposta do biossensor é medida a partir da diminuição da corrente produzida. Isso ocorre porque o MP se encontra em contato com a AChE e inibe a ação da mesma, impedindo a hidrólise da ATCl, o que faz diminuir a corrente, pois não há produção de tiocolina, que é produto da hidrólise e uma espécie eletroativa. Os filmes apresentaram sensibilidades (% de inibição por mmol L-1 de pesticida) de 1,9×106 (R2 0,976) e 2,7×106 (R2 0,964) e limites de detecção de 4,15 e 14,8 ng L-1, para PPi-IC-AChE e PPi-IC-NPAu-AChE respectivamente. / The goal of this work was to study and characterize nanocomposite films of gold nanoparticles with indigo carmine and dodecylsulfate doped polypyrrole for application as electrochemical biosensor for pesticide. Initially, three films were synthesized by cyclic voltammetry at 10 and 25 ºC: polypyrrole doped with indigo carmine (PPy-IC), polypyrrole doped with indigo carmine containing gold nanoparticles (PPy-IC-AuNP) and polypyrrole doped with indigo carmine and sodium dodecylsulfate containing gold nanoparticles (PPy-IC-DS-AuNP). These films were studied by structural, morphological, optical and electrochemical characterization, using infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, UV-VIS-NIR spectroscopy and cyclic voltammetry. The films synthesized at 10 ºC were modified with acetylcholinesterase (AChE) enzyme; followed by characterization with scanning electron microscopy, Raman spectroscopy and cyclic voltammetry The results showed a preferential immobilization of the enzymes on films without DS, therefore, PPy-IC and PPy-IC-AuNP were the most suitable materials for the physical immobilization of AChE and for detection of methyl parathion (MP) pesticide through the percentage of pesticide inhibited by the action of AChE on acetylthiocholine chloride (ATCl). This detection was carried out by cyclic voltammetry, where the biosensor response is measured as a decrease of the produced current. The decrease in current occurs because MP reaches the AChE, inhibiting the action of the enzyme, avoiding the hydrolysis of ATCl, leading to the decrease of current as no thiocholine (an electroactive specie, product of the hydrolysis) is produced. The films presented sensitivities (inhibition percentage per mmol L-1) of 1.9×106 (R2 0.976) and 2.7×106 (R2 0.964) and detection limits of 4.15 and 14.8 ng L-1 for PPy-IC-AChE and PPy-IC-AuNP-AChE respectively.

Nanocompósitos de PMMA/ argila montmorilonita foram obtidos por fotopolimerização in situ. O metacrilato de metila foi polimerizado na presença de argilas modificadas usando Tioxantona (TX) e etil 4-(dimetilamino) benzoato (EDB) como sistema fotoiniciador. As argilas montmorilonitas SWy-1 modificadas, SWy-1-C8 e SWy-1-C16, foram preparadas pela troca de íons com brometo de octiltrimetilamônio (C8) e brometo de hexiltrimetilamônio (C16), respectivamente. A difração de raios-X indicou que os compósitos de PMMA/argila podem ter estruturas intercaladas ou esfoliadas, ou mesmo uma mistura de estruturas em camadas esfoliada e parcialmente intercalada. A estrutura de cada nanocompósito depende da concentração de argila e do solvente utilizado na preparação. A influência da concentração de argila organofílica, natureza do solvente e tipo de argila nas propriedades térmicas e mecânicas foi estudada por análise termogravimétrica e análise dinâmico-mecânica. Todos os nanocompósitos preparados em acetonitrila exibiram melhora da sua estabilidade térmica, principalmente devido à interação entre a argila e o polímero que é maximizada através da estrutura da argila esfoliada. No caso do PMMA e nanocompósitos sintetizados em etanol, a estabilidade térmica do polímero e nanocompósitos foi praticamente a mesma, uma vez que a estrutura da argila é predominantemente do tipo intercalada. Na velocidade de polimerização observou-se que os fatores que mais influenciaram foram a concentração de argila e o tipo de solvente. A argila proporciona a formação de microambientes que estabilizam o estado excitado do iniciador formando mais radicais livres e consequentemente aumentando a velocidade polimerização. A utilização da acetonitrila, a qual é um melhor solvente para o PMMA proporcionou massas molares menores. A degradação foto-oxidativa dos nanocompósitos de PMMA/ argila foi investigada utilizando cromatografia de exclusão de tamanho (SEC). Foram encontradas evidências de que o PMMA e nanocompósitos degradam por cisões aleatórias de cadeias. A polidispersidade aumentou após a irradiação e o coeficiente de degradação de PMMA puro é de até seis vezes maior do que para os nanocompósitos. O efeito sobre os coeficientes de fotodegradação da concentração de argila, tipo argila (argila modificada por agentes tensoativos com diferentes comprimentos de cadeias de alquílica) e o solvente utilizado para a dispersão de argila orgânica, também foram estudados. / Montmorillonite clay/PMMA nanocomposites were obtained by in situ photopolymerization. Methyl methacrylate was polymerized in the presence of modified clays using thioxanthone (TX) and ethyl 4-(dimethylamino) benzoate (EDB) as photoinitiating system. The SWy-1 montmorillonite modified clays, SWy-1-C8 and SWy-1-C16, were prepared by ion exchange with octyltrimethylammonium bromide (C8) and hexyltrimethylammonium bromide (C16), respectively. X-ray diffraction indicated that clay/PMMA composites have intercalated or exfoliated structures, or even a mixture of exfoliated and partially intercalated structure layers. The structure of each particular nanocomposite depends on the clay loading and the solvent used for the preparation.The influences of organoclay loading, solvent nature and clay type on thermal and mechanical properties were studied by thermogravimetric analysis and dynamic mechanical analysis. All the nanocomposites prepared in acetonitrile exhibited improvement in their thermal stability, mainly due to the interaction between the clay and the polymer which is maximized by the exfoliated clay structure. In the case of PMMA and nanocomposites synthesized in ethanol, the thermal stability of polymer and nanocomposites remained practically the same once the clay structure is predominantly of the intercalated type. It was observed that the factors that most influenced the polymerization rate were the concentration of clay and type of solvent. The clay provides the formation of microenvironments that stabilizes the excited state of the initiator forming free radicals and consequently increasing the polymerization rate. The use of acetonitrile, which is a better solvent for PMMA gave the lowest molar weight. The photooxidative degradation of clay/PMMA nanocomposites has been investigated using size exclusion chromatography (SEC). Evidence was found that PMMA and composites degrade by random chain scissions. The polydispersity increases after irradiation and the degradation rate coefficient for pure PMMA is up to 6 times larger than that for the composites. The effect on the photodegradation rate coefficients of the clay content, clay type (clay modified by surfactants with different lengths of alkyl chains) and solvent used for dispersion of organic clay were also studied. The relationship of these parameters on the photodegradation process was statistically evaluated using a two-level factorial design.

Thesis (MSc. (Chemistry)) -- University of Limpopo, 2016 / 2-Benzenesulfonyloxyquinoxaline was prepared following literature procedure followed by palladium-catalysed Negishi coupling reactions to yield the corresponding, 2-mono-substituted quinoxaline derivatives, 2-phenylquinoxaline and 2-butylquinoxaline. These Negishi cross-coupled derivatives were treated with various nucleophiles, in tetrahydrofuran at room temperature, to yield a series of di-substituted quinoxaline derivatives containing; aryl-, heteroaryl-, arylalkynyl- and alkyl-substituents. Tri-substitution was successful with reaction of 6-chloro-2-benzenesulfonyloxyquinoxaline with excess phenyl-magnesium bromide to yield 2,3,6-triphenylquinoxaline. Sonogashira cross-coupled compounds were successfully synthesised by reacting 2-benzenesulfonyloxyquinoxaline, 6-nitro-2-benzenesulfonyloxyquinoxaline and 6-chloro-2-benzenesulfonyloxyquinoxaline using phenylacetylene, respectively. Nucleophilic substitution was only successful on 2-(2-phenylethynyl)quinoxaline to yield 3-butyl-2-(2-phenylethynyl)quinoxaline. The formation of carbon-nitrogen bonds was accomplished via palladium-catalysed Buchwald-Hartwig amination of 2-benzenesulfonyloxyquinoxaline with arylamines to afford N-phenylquinoxalin-2-amine and N-benzylquinoxalin-2-amine in good to high yields. N-phenylquinoxalin-2-amine was subsequently treated with iodomethane to synthesise N-methyl-N-phenylquinoxalin-2-amine. Nucleophilic substitution on Buchwald-Hartwig coupled compounds was only successful when using alkyl nucleophiles. The reaction of all these quinoxaline derivatives with various nucleophiles does not stop at the stage of α-adduct formation, but continues with the oxidation of these compounds to aromatic substitution products. All synthesised compounds were characterised by NMR, and mass spectral data as well as melting points where applicable. N-Methyl-N-phenylquinoxalin-2-amine and 2,3,6-triphenylquinoxaline showed percentage parasite viability of 42.64% and 58.12%, respectively, against the Plasmodium falciparum strain 3D7. N-Methyl-N-phenylquinoxalin-2-amine showed MIC90 of 16.4 and MIC99 of 19 μM, while 6-chloro-2-(2-phenylethynyl)quinoxalin showed MIC90 of 8.15 and MIC99 of 9.26 μM values against Mycobacterium tuberculosis (Mtb)-H37Rv strains.

Thesis (M.Sc.(Agricultural Management )) -- University of Limpopo, 2020 / Avocado fruit ‘Hass’ harvested during early-season and exposed to temperature at 5.5°C for 28 d are susceptible to chilling injury (CI); and therefore, develop poor skin colour during ripening. In ‘Hass’ avocado fruit, skin colour change during ripening is used by European market to indicate fruit ripeness and softness. Therefore, the aim of this study was to evaluate the use of hot water (HW) and methyl jasmonate (MJ) as postharvest treatment dips to mitigate CI; and thereby, enhance ‘Hass’ avocado fruit peel colour during ripening. Fruit were harvested randomly from 5 selected trees treated alike during early season (April 2018); and thereafter, transported to the laboratory. At the laboratory, experiments of this study were divided into 2: experiment (1) fruit were dipped into HW (38, 42 and 46°C for 30, 25 and 20 min, respectively); and experiment (2) fruit were dipped into MJ (10 and 100 µmol/L for 2 min) treatments. In both experiments after these treatments, fruit were allowed to dry for 60 minutes at ambient (±25°C) temperature and untreated fruit were used as control. Thereafter, fruit were stored at commercial shipping temperature (5.5°C) for up to 28 d. After removal from cold storage, fruit were ripened at ambient temperature (±25°C) and evaluated every after 2 d for weight loss, firmness loss, objective colour parameters (lightness-L*, chroma-C* and hue angle-h*), subjective colour (eye colour) and ripening percentage. However, chilling injury (CI) and electrolyte leakage (EL) were evaluated immediately after removal from cold storage. The results showed that HW significantly (P< 0.05) increased weight and firmness loss during ripening. Furthermore, HW reduced EL and external chilling injury (ECI) of ‘Hass’ avocado fruit during cold storage. In addition, the results showed that HW had significant effect (P< 0.05) on colour parameter L* and eye colour rating, but did not affect (P> 0.05) C* and h*. Avocado ‘Hass’ fruit subjected to HW at 42°C/25 and 46°C/20 min developed purple colour (eye colour rating 4.47 and 4.36, respectively) during ripening when compared with HW at 38°C/30 min and control fruit. Moreover, results showed that dipping fruit in 10 µmol/L had a significant effect (P< 0.05) on reducing weight loss during ripening. Methyl jasmonate (10 and 100 µmol/L) treatment reduced EL and alleviated external chilling injury (ECI) of ‘Hass’ fruit during cold storage. The results showed that MJ (10 and 100 µmol/L) treatments had significant effect (P< 0.05) on colour parameter L*, h* and eye colour rating, but did not affect (P> 0.05) C*. Furthermore, ‘Hass’ fruit treated with 10 and 100 µmol/L MJ reached the purple skin colour (eye rating 5.39 and 5.19, respectively) during ripening. Fruit dipped in MJ (10 µmol/L) had low weight loss when compared with fruit treated with MJ (100 µmol/L). In conclusion, the results of this study indicated that HW (42°C/25 minutes) and MJ (10 µmol/L) effectively alleviated external chilling injury; and therefore, improved ‘Hass’ skin colour development during ripening / Agricultural Research Council-Institute (Agriseta) and University of Limpopo

V této práci byl popsán princip fotokatalýzy. Práce se soustřeďuje na kovové oxidy, které mají široké využití ve fotokatalytických aplikacích. Bylo také popsáno různé použití fotokatalytických materiálů. Tato práce se zaměřuje zejména na využití fotokatalytických materiálů pro rozklad organických vodu znečisťujících látek. Popsaný fotokatalyzátor je oxid měďný, který má velmi dobré vlastnosti pro rozklad organických látek pomocí fotokatalýzy. Schopnost rozkladu organických látek oxidu měďného byla popsána na rozkladu organického barviva methylová oranž.

>Magister Scientiae - MSc / Anxiety, resilience and childhood trauma can be categorized as functional behavioural categories, with a wealth of research behind each. The research approach adopted for each, in most cases, is either from a genetic or neuropsychological standpoint, with few studies combining both to better understand all three functional behavioural categories as a multidimensional construct A number of candidate genes have been identified as markers for anxiety, resilience and childhood trauma, of which Catechol-methyl-transferase (COMT) and several respective single nucleotide polymorphisms (SNPs) are included. Although COMT SNPs have been linked to at least one of the functional categories, with a handful of haplotypes identified, to our knowledge no study has investigated the combination of SNPs selected for this study (rs6269, rs4818, rs4680, rs4633, rs737865, rs2075507) as a possible haplotype, specifically in a South African population. The use of SNaPshot for the genotyping of genes is an efficient and reliable means of identifying genotype frequencies and haplotypes in large sample groups, yet when selecting more than two SNPs of interest, the development of a multiplex assay is ideal. The first aim of the study was to design and optimize a multiplex assay to genotype several COMT SNPs. The primer design, multiplex optimization and SNaPshot conditions used showed good working parameters that can be utilized and further improved by optimization. Self-report measures are widely used to measure psychiatric disorders, such as anxiety, and has also been used for the measurement of resilience and childhood trauma. With each functional behavioural category well investigated in its respective domain, there is a need to investigate all three as a collective in a South African population due to the high rate of anxiety and childhood trauma exposure in communities. The second aim of the study was to investigate the prevalence of anxiety, resilience and childhood as functional behavioural categories in the full South African sample group; and the role of sex, through established self-report measures and respective normative data. Additionally, this carried over into investigating the correlation between anxiety, resilience and childhood trauma as a multidimensional construct in both the full South African sample and between sexes. There is a clear relationship which exists between all three functional behavioural categories, as they show a correlation in various dimensions independent of one another. Higher anxiety levels amongst females were reported, with no difference between sexes for resiliency. The empirical data collected from both COMT SNP and self-report measures for male and female where explored and reviewed against current literature for better understanding and insight into the association of COMT SNPs with anxiety, resilience and childhood trauma in a South African population. The results of this study to understand the complexity and association of all three functional behavioural categories as a multidimensional construct will be invaluable and may assist in the identification of possible risk factors which are essential for the promotion of better mental health in society.

Ever since their discovery, Carbon nanotubes (CNTs) have been renowned to be potential candidates for a variety of applications. Nevertheless, the difficulties accompanied with their dispersion and poor solubility in various solvents have hindered CNTs potential applications. As a result, studies have been developed to address the dispersion problem. The solution is in modifying the surfaces of the nanotubes covalently or non-covalently with a desired dispersant. Various materials have been employed for this purpose out of which polymers are the most common. Non-covalent functionalization of CNTs via polymer wrapping represents an attractive method to obtain a stable and homogenous CNTs dispersion. This method is able to change the surface properties of the nanotubes without destroying their intrinsic structure and preserving their properties. This thesis explores and studies the surface modification and solublization of pristine single and multiwalled carbon nanotubes via a simple solution mixing technique through non-covalent interactions of CNTs with various anionic and cationic conjugated polyelectrolytes (CPEs). The work includes studying the interaction of various poly(phenylene ethynylene) electrolytes with MWCNTs and an imidazolium functionalized poly(3-hexylthiophene) with SWCNTs. Our work here focuses on the noncovalent modifications of carbon nanotubes using novel CPEs in order to use these resulting CPE/CNT complexes in various applications. Upon modifying the CNTs with the CPEs, the resulting CPE/CNT complex has been proven to be easily dispersed in various organic and aqueous solution with excellent homogeneity and stability for several months. This complex was then used as a nanofiller and was dispersed in another polymer matrix (poly(methyl methacrylate), PMMA). The PMMA/CPE/CNT composite materials were cast or electrospun depending on their desired application. The presence of the CPE modified CNTs in the polymer matrix has been proven to enhance the composites thermal, mechanical and electrical properties compared to pristine CNTs. Various spectroscopic and microscopic techniques such as UV-vis, fluorescence, TEM, AFM and SEM were used to study and characterize the CPE/CNT complexes. Also, TGA, DSC and DMA were used to study the thermal and mechanical properties of the composite materials. Our current work represents a fundamental study on the non-covalent interactions between CNTs and CPEs on one hand and gives a real life example on the CPE/CNT application in composite materials and electronics.

The effects of various catalyst synthesis parameters on the photocatalytic degradation kinetics of aqueous methyl orange dye are presented. The four factors investigated were: i) InVO4 concentration, ii) nickel concentration, iii) InVO4 calcination temperature, and iv) ballmilling time. Three levels were used for each factor. Due to the large number of possible experiments in a full factorial experiment, an orthogonal-array experimental design was used. UV-vis spectrophotometry was used to measure the dye concentration. The results show that nickel concentration was a significant parameter, with 90% confidence. The relative ranking of importance of the parameters was nickel concentration > InVO4 concentration > InVO4 calcination temperature > milling time. The results of the orthogonal array testing were used to make samples of theoretically slowest and fastest catalysts. Curiously, the predicted-slowest catalyst was the fastest overall, though both samples were faster than the previous set. The only difference between the slowest and fastest catalysts was the milling time, with the longer-milled catalyst being more reactive. From this result, we hypothesize that there is an interaction effect between nickel concentration and milling time. The slowest and fastest catalysts were characterized using energy-dispersive spectroscopy (EDS), scanning electron microscopy (SEM), x-ray powder diffractometry (XRD), BET surface area analysis, and diffuse-reflectance spectroscopy (DRS). The characterization results show that the fastest catalyst had a lower band gap than the slowest one, as well as a slightly greater pore volume and average pore diameter. The results indicate that fast kinetics are achieved with low amounts of nickel and a long ball milling time. Under the levels tested, InVO4 concentration and the calcination temperature of the InVO4 precursor were not significant.

Background: One key component in the development of sustainable farming and foodstuffs is to increase the cultivation of legumes, due to their environmental and health benefits. Legumes contain several essential vitamins and minerals, protein and fiber, but cultivation can be problematic due to their weak stem strength which results in loss of crops as a result of crop lodging and susceptibility to weed invasion. One possible solution is co-cultivation with cereal crops such as oats as they provide support and outcompete weed growth, however, it is still unknown if co-cultivation will affect the nutrient content of lentils. Aim: The thesis has two aims: first, to compare choline, betaine, folate, resistant starch and dietary fiber content in two different types of lentils: Gotland lentils and Anicia lentils; and second to examine if cocultivation with oats will affect the nutrient content of the two lentil types. Methods: Betaine and choline were analyzed through high pressure liquid chromatography-mass spectrometry (HPLC-MS) and folate through high pressure liquid chromatography with fluorometric/UV detection (HPLC-FL/UV). Resistant starch, non-resistant starch and dietary fiber were analyzed according to enzymatic assay kits by Megazyme. Results: Significant differences in nutrient content between Anicia and Gotland lentils were seen regarding resistant starch content, with Gotland showing a 50 % higher content. A significantly greater choline content was found in Anicia lentil samples that were co-cultivated with oats, showing approx. a 15 % higher choline content. Gotland lentils co-cultivated with oats showed a significantly greater choline, resistant starch and dietary fiber content by 15 %, 70 % and 10 %, respectively. Conclusions: There was no reported significant difference in choline, betaine, folate and dietary fiber content, but in resistant starch between the two lentil types, with Gotland lentil showing a higher resistant starch content. There appeared to be a positive effect of co-cultivation with oats since a significantly higher choline content in both lentil types co-cultivated with oats and a significant increase resistant starch and dietary fiber in Gotland lentils co-cultivated with oats was reported. This suggests that cocultivation can lead to an increase in nutritional content for some nutrients in Gotland and Anicia lentils. The dietary fiber analysis confirmed that legumes are a great source of fiber by one portion providing approx. half the recommended daily amount. Cultivation and consumption of lentils can give both environmental and health benefits. Further studies are needed to explore other pulses and effect on other nutrients. / Svenska ekologiska linser

京都大学 / 0048 / 新制・課程博士 / 博士(薬科学) / 甲第22046号 / 薬科博第112号 / 新制||薬科||12(附属図書館) / 京都大学大学院薬学研究科医薬創成情報科学専攻 / (主査)教授 土居 雅夫, 准教授 Fustin,Jean Michel, 教授 中山 和久 / 学位規則第4条第1項該当 / Doctor of Pharmaceutical Sciences / Kyoto University / DFAM