A realização deste trabalho objetivou a avaliação quantitativa da absorção da radiação UVB (290-320 nm) em oito amostras de própolis, incorporadas em base cosmética apropriada, sob a forma de extrato mole, originárias de diversas regiões com diferentes origens botânicas sendo duas de Minas Gerais, três de São Paulo, uma de Santa Catarina, uma do Rio Grande do Sul e outra da Pensilvânia - EUA. A estimativa de absorção foi feita através de método espectrofotométrico com medidas de absorbâncias na faixa entre 290 a 320 nm, tomadas de 5 em 5 nm. Cada medida de absorbância foi relacionada à intensidade e ao efeito eritemogênico da radiação em seu respectivo comprimento de onda. Os resultados tiveram como parâmetro o padrão de referência salicilato de homomentila, aprovado pela FDA para determinação de FPS in vivo. Foi obtido um perfil cromatográfico através de cromatografia em camada delgada para avaliação qualitativa de nossas amostras em relação a alguns flavonóides e ácidos aromáticos, o que nos permitiu constatar a presença de ácido cafeico em todas as amostras analisadas. Foram dosados flavonóides totais por método colorimétrico com cloreto de alumínio, expressos em crisina a 330 nm. Foi feita a comparação entre os resultados de FPS e flavonóides totais e observamos proporcionalidade direta entre a maioria das amostras, o que confirma a ação de absorção de radiação ultra-violeta por flavonóides colhidos pelas abelhas em plantas. / The aim of this work was to evaluate quantitatively the UVB absorption (290-320 nm) of propolis, contained in eight cosmetic samples as soft extract, from different botanical origins and several regions, such as Minas Gerais, São Paulo, Santa Catarina, Rio Grande do Sul and Pennsylvania (USA). A spectrophotometric method using absorbance measurements in a range of 290-320 nm, taken at 5 nm intervals, was used to asses the absorbance. Each absorbance measurement was related to both intensity and erythemal effect of the radiation at its respective wavelength. Homosalate, which is approved by the FDA as reference standard, was used for the determination of SPF in vivo. Chromatograms of the samples were obtained by thin-layer chromatography to evaluate the presence of some flavonoids and aromatic acids in the samples. This technique allowed the detection of caffeic acid in all the analyzed samples. The total flavonoids content was assayed by the colorimetric method using aluminum chloride, and the results were expressed in chrysin at 330 nm. A comparison between the SPF results and the total flavonoids contend was done and a direct relationship between most of the samples was observed, confirming the absorbing ultraviolet radiation property of the flavonoids collected by bees.

Esta Tese apresenta duas revisões de literatura: 1. Síntese de aldeídos e cetonas a partir de compostos de enxofre. 2. Síntese de benzaldeídos deuterados. E descrita a reação de sulfenilação de benzil fenil sulfonas, conduzindo a um novo \"synthon\", α-metiltio-benzil fenil sulfona (1). Y-C6H4-CH(SCH3)SO2C6H5 Y = H,CH3,Cl,OCH3,NO2,CN. É relatada a hidrólise ácida de (1), fornecendo benzaldeídos para substituídos. É proposta a decomposição térmica de (1), como um método novo de síntese de benzaldeídos para substituídos. É descrita uma reação de um passo só, envolvendo alquilação e decomposição térmica de (1) e fornecendo cetonas aromáticas. Este método permite sintetizar cetonas contendo grupos sensíveis a ácidos. O método pirolítico é aplicado à síntese de aldeídos aromáticos deuterados, que são obtidos em 98% de pureza isotópica. Os benzaldeídos deuterados e não deuterados são obtidos em bons rendimentos, não se notando diferenças provenientes do caráter eletrônico dos substituintes no anel. É apresentada uma discussão sobre os aspectos mecanísticos da decomposição térmica. / This thesis presents two literature reviews: 1. Synthesis of aldehydes and ketones, starting from the sulphur containing compounds 2. Synthesis of deuterated benzaldehydes. The sulphenylation reaction of benzyl phenyl sulphones, leading to a new \"synthon\", α-methylthio-benzyl phenyl sulphone (1), is described. Y-C6H4-CH(SCH3)SO2C6H5 Y = H,CH3,OCH3,Cl,NO2,CN. Acid hydrolyses of (1) to give p-substituted benzaldehydes are reported. A novel reaction - Thermal Oecomposition of (1) - as an improved method for the synthesis of p-substituted benzaldehydes is proposed. One pot reaction, which consists of alkylation and thermal decomposition of (1), to give aromatic ketones, is reported. Some ketones containing acid-sensitive groups are obtained. The pyrolyt ic method is applied to the synthesis of deuterated aromatic aldehydes, which are obtained in 98% of isotopic purity. The yields of the deuterated and non-deuterated benzaldehydes are good, and do not show any dependence on the eletronic character of the para substituents. A discussion on some mechanistic aspects of the thermal decomposition is presented.

Aldol cyclotrimerizations have been used to achieve the rational chemical synthesis of both fullerenes and fullerene fragments in the past. Under certain conditions this reaction produces the corresponding cyclotetramer which has sometimes been regarded as an undesired byproduct. This work details efforts to synthesize and use these cyclotetramers toward a synthesis of a C240 fullerene fragment. One principal focus in this work is tridecacyclene, a cyclic tetramer of acenaphthylene given its name by our group for its thirteen rings. Relatively low yields for the synthesis of tridecacyclene and its derivatives drove us to investigate the mechanism of its formation and attempt to optimize its production. During this process, novel dione products were isolated from the attempted cyclotetramerization of two dimeric species. Characterization of these products by X-ray crystallography gave valuable insight into the reaction pathway, leading us to a new proposed mechanism of formation for the cyclotetramerization products observed in these aldol reactions. β-hydroxy-α-diazoketones are suitable progenitors to vinyl cation intermediates whose use in chemical synthesis is relatively unexplored. As part of an extensive project to develop the chemistry of vinyl cations for use in carbon-carbon bond forming reactions to build important molecular scaffolds, a range of β-hydroxy-α-diazoketones containing a pendent nucleophilic alkene were synthesized. Treatment of these compounds with Lewis acids gave either lactone or cyclopentenone products depending on the substrate used. Proposed herein is a mechanism involving a key acylium intermediate which, depending on the position of the pendent alkene, results in different product outcomes. In a collaborative effort to further investigate the known anti-cancer properties of fusarochromanone, a fungal metabolite that is isolated from Fusarium-infected feed from cold climates, a large-scale synthesis of this natural product was explored. An efficient, scalable synthesis of the previously prohibitively expensive amidochromanone starting material has been achieved and its elaboration to fusarochromanone has been demonstrated.

We have investigated the size-dependent stability and structure of benzene, aluminum-benzene, and vanadium-benzene clusters. Motivated by gas-phase experimental studies performed by an experimental collaborator, we have used first-principle electronic structure methods to identify the structure of Al+(Bz)n, V+(Bz)n, and Bzn clusters. Our studies reveal that cationic aluminum-benzene clusters have a magic number of 13, and that its high stability may be understood by analyzing the structure of the cluster. We also investigate the structure of vanadium-benzene clusters which have a magic number of 2. Here I examine the benzene-cation and benzene-benzene interactions that lead to these magic numbers, as well as their geometric shell structures and their formation/solvation.

A investigação de degradação de compostos-modelo de lignina por meios eletroquímicos integra a linha de pesquisa desenvolvida neste grupo há um certo tempo. Neste trabalho utilizou-se 4 compostos-modelo de lignina cujos anéis aromáticos representam unidade siringila, ou seja, três átomos de oxigênio ligados ao anel. São eles: 2-(4-metoxifenóxi)-1-(3,4,5-trimetoxifenil)-etanona (CM-I), 2-(2-metoxifenóxi)-1-(3,4,5-trimetoxifenil)-etanona (CM-II) e os dois álcoois correspondentes (CM-III) e (CM-IV), respectivamente. Para sintetizar estes 4 compostos, foi necessário realizar uma rota sintética que se iniciou com a metilação do ácido 3,4,5-tri-hidroxibenzóico até chegar ao composto chave 2-bromo-1-(3,4,5-trimetoxifenil)-etanona (4). A etapa de bromação da 3,4,5-trimetoxiacetofenona (3) foi a mais problemática pois em vários métodos distintos de bromação a cetona dibromada era obtida como produto secundário. A reação de bromocetona com o fenol 2- ou 4-metoxilado conduziu às cetonas (CM-I) e (CM-II) desejadas. Ambas foram reduzidas aos álcoois (CM-III) e (CM-IV) com borohidreto de sódio Os experimentos eletroquímicos de voltametria cíclica dos 4 compostos-modelo usando anodo de Pt em acetonitrila contendo perclorato de sódio revelaram que suas oxidações eram irreversíveis. Eletrólises preparativas foram feitas principalmente em metanol contendo metóxido de sódio. Quanto à eletrólises preparativas das duas cetonas CM-I e CM-II, observou-se que na oxidação de CM-I houve formação de mistura complexa de produtos enquanto que na de CM-II, parte do material de partida foi recuperado. Já nas oxidações dos álcoois, os resultados obtidos dependeram principalmente da posição da metoxila no grupo fenóxi ligado à cadeia lateral. Quando esta metoxila se encontrava na posição orto, as misturas de reação continha como componente principal o material de partida. Com a metoxila na posição para, dois compostos principais foram isolados, e os seus dados espectroscópicos são coerentes com os esperados para derivados do 1,4-dioxaspiro-[4,5]deca-6,9-dieno. / The investigation of the electrochemical degradation of lignin model compounds has been part of the research developed in this group for a certain time. In the present work 4 lignin model compounds, in which one of the aromatic rings is representative of syringyl units, were used. They are, 2-(4-methoxyphenoxy)-l(3,4,5-trimethoxyphenyl)-ethanone ( CM-I), 2-(2-methoxyphenoxy )-1-(3,4,5-trimethoxyphenyl)-ethanone (CM-II) and their corresponding alcohols (CM-III) and (CM-IV), respectively. To synthesize these 4 compounds, a synthetic route was developed, beginning with the methylation of the 3,4,5-trhydroxy-benzoic acid. The key compound of this synthetic route was 2-bromo-1-(3,4,5-trimethoxyphenyl)-ethanone (4). The bromination of the 3,4,5-trimethoxyacetophenone was the most problematic step, because the dibromated ketone was obtained as a by product in distinct methods. The reaction of the 2-bromo-1-(3,4,5-trimethoxyphenyl)-ethanone with 2- and 4- methoxylated phenols afforded CM-I and CM-II. Both were reduced to CM-III and CM-IV with sodium borohydride. The cyclic voltammetric experiments of the 4 model compounds using platinum anode in MeCN/ 0,1 M NaClO4 revealed that their oxidations were irreversible. Preparative electrolyses were made mostly in MeOH/MeONa. The electrolyses of the two ketones showed that when CM-I was oxidized a complex mixture of products was obtained, while in the oxidation of CM-II part of the starting material was recovered. In the oxidations of the two alcohols, the results obtained depended mostly on the position of the methoxy group in the phenoy group connected to the carbon-carbon side chain. When the methoxy group was at the ortho position, the reaction mixture contained the starting material as the main product. When this methoxy group was at the para position, two major compounds were isolated, and their spectroscopic data are consistent with those expected for 1,4-dioxaspiro-[4,5]-deca-6,9-diene derivates.

This thesis reports the results of investigations carried out into the composition of the saturate and aromatic unresolved complex mixtures (UCMs) in crude oils. It is divided into two sections. Section A reports on studies of the saturate UCM and Section B reports on studies of the aromatic UCM. UCMs are mixtures of very large numbers of compounds of low individual abundances, hence structural information on individual components is difficult or impossible to obtain using conventional GC or GC-MS techniques. The investigations reported in this thesis used a combination of GC-MS techniques (Section A) and oxidations of UCMs followed by GC-MS characterisation of the oxidation products (Section B) to develop a more detailed picture of the structures of components of the saturate and aromatic UCMs. UCMs are present in all crude oils, and may account for the vast majority of the material present in heavily weathered or biodegraded oils. An understanding of the types of compounds present may have a bearing on the refining processes an oil is subjected to, as well as assessing its potential environmental and toxicological effects.Single branched C(subscript)18 isomers were prepared to establish the chromatographic behaviour and mass spectral fragmentation patterns of open chain compounds with ethyl-, propyl-, butyl- and pentyl- substituents. All open chain structural isomers with a single n-alkyl branch larger than methyl in the range C(subscript)10 to C(subscript)20 were identified at each carbon number in a series of crude oils of varying ages, source types and depositional environments. Also, C(subscript)21 to C(subscript)25 structural isomers containing an ethyl branch were identified in all of these samples. This represents a total of 163 compounds. These monoalkylalkanes comprise approximately 3 % of the alkanes in these oils, with the n-alkanes (35-60 %) and ++ / methylalkanes (10 %) being the most abundant compound classes present. Isoprenoids, alkylcyclohexanes and other branched and/or cyclic alkanes make up the remainder of the material.Rock samples from a sedimentary sequence of Late Cretaceous age were analysed for ethylalkanes using GC-MS techniques. In the less mature samples, 3- and 5-ethylalkanes were in higher abundance relative to the other isomers at odd carbon numbers from C(subscript)17 to C(subscript)23. In the more mature samples, this odd preference was no longer apparent. Several other low maturity sediment samples were analysed and found to have a similar ethylalkane distribution to the shallow sample from the sedimentary sequence. A mature crude oil which was also analysed exhibited a distribution similar to the deeper sample from the sedimentary sequence. Tetralin pyrolysis of a low maturity lignite sample yielded only the 3- and 5-substituted ethylalkanes, providing supporting evidence that the initial odd preference is the result of defunctionalisation of specific natural product precursors containing a 3- or 5-ethylalkyl structural moiety. With increasing maturity this preference is diluted by input of ethylalkanes without preference. A mechanism involving acid-catalysed rearrangement of n-alkenes to form monoalkylalkanes is proposed to account for the loss of preference in ethylalkane relative abundances.Investigations into the composition of aromatic unresolved complex mixtures were conducted by oxidising the total aromatic fraction of a moderately biodegraded crude oil (biodegradation level 4) using potassium permanganate. This reagent cleaves the alkyl substituents attached to aromatic rings between the alpha and beta carbons and oxidises the alpha carbon to a carboxylate group. A biodegraded crude oil was chosen because the majority of the resolved components have been removed by biodegradation, ++ / leaving a complex mixture of compounds almost completely unresolved by gas chromatography. The oxidation product was separated into dichloromethane-soluble monocarboxylic acids (both aliphatic and aromatic) and water-soluble polycarboxylic acids (aromatic only). GC-MS analysis of these oxidation products gave the proportions of monosubstituted:disubstituted:trisubstituted:tetrasubstituted monoaromatic rings as 29:59:12:0.1, of which from one to three substituents were carboxylic acid groups with the remainder of the substituents being unoxidised methyl groups. Of the disubstituted monoaromatic oxidation products, 53 % were dicarboxylic acids with the most sterically hindered 1,2-substitution pattern. This observation was interpreted as evidence for the presence of significant amounts of naphthenoaromatic systems such as tetralins and indanes in the crude oil aromatic fraction. Analysis of the permanganate oxidation products also enabled a quantitative measure of the proportion of methyl substituents to be made. It was found that methyl groups accounted for a significant proportion of the alkyl substituents attached to aromatic systems. Of the disubstituted monoaromatic oxidation products, 59 % had a methyl group as one of the substituents, while of trisubstituted monoaromatic systems, 41% had one methyl and 37 % had two methyls. Compounds containing a biphenyl carbon skeleton comprised 3 % of the aromatic oxidation products, with isomers containing from one to four substituents of which one was a carboxylic acid group and the remainder were unoxidised methyls. This indicates that biphenyls containing more than one alkyl (>C(subscript)1) substituent were not present. Of the monosubstituted biphenylcarboxylic acids, the ratio of ortho:meta:para substituted isomers was 0:65:35, which correlates well with literature reports of the relative abundances of methylbiphenyl ++ / isomers, and suggests that the overall distribution of all monosubstituted biphenyls has not been significantly affected by biodegradation to level 4.The monoaromatic, diaromatic and triaromatic fractions of the same biodegraded crude oil (level 4) were separately treated with ruthenium tetroxide, which cleaves aromatic rings so that the ring carbon bearing the substituent is oxidised to become the carbonyl carbon of a carboxylic acid. These oxidation products represent the alkyl moieties that were attached to aromatic rings in the initial crude oil aromatic fractions. Identification of these alkyl side chains provides an insight into the nature of the components of the aromatic crude oil UCM. The oxidation products were separated into dichloromethane-soluble monocarboxylic acids, which were subsequently reduced to monodeuterated hydrocarbons for characterisation using gas chromatography-mass spectrometry (GC-MS) techniques, and water-soluble dicarboxylic acids which were analysed as dimethyl esters. n-Alkanes, methylalkanes, alkylalkanes, alkylcyclohexands, methylalkylcyclohexanes, isoprenoids and bicyclic alkanes were identified in the monodeuterated hydrocarbon samples derived from all three aromatic fractions. Most of these compounds had carbon skeletons strikingly similar to those observed in the saturate fractions of unbiodegraded crude oils, with the only differences being the addition of a carbon from the aromatic ring, and the presence of a deuterium atom attached to that carbon. Because the electron-withdrawing nature of carboxylic acid groups prevents further aromatic ring oxidation, numerous aromatic monocarboxylic acids were also identified in the acidic products of the oxidation of the crude oil diaromatic and triaromatic fractions. These included C(subscript)1 to C(subscript)3 alkyl-substituted benzoic acids derived from compounds containing a biphenyl ++ / or phenylnaphthalene structural moiety, as well as omega-phenylalkanoic acids with chain lengths up to C(subscript)11, derived from compounds in which two aromatic systems are connected by an alkyl chain. The main components of the dicarboxylic acid oxidation products of all three aromatic fractions were alpha, omega-dicarboxylic acids and alkylcyclopentane-dicarboxylic acids and alkylcyclohexane-dicarboxylic acids, with phthalic acids also present in the oxidation products of the diaromatic and triaromatic fractions. The observation that 1,5-pentanedicarboxylic acids and 1,6-hexanedicarboxylic acids were the only alpha, omega-dicarboxylic acids in the oxidation products of the crude oil monoaromatic fraction, and were present in high abundance relative to other alpha, omega-dicarboxylic acids in the oxidation products of the diaromatic and triaromatic fractions indicated that substituted indanes and/or tetralins were quantitatively important constituents of the overall crude oil aromatic fraction. This finding is supported by the results of the analysis of the mass spectra of the crude oil aromatic fractions.These studies of aromatic UCMs have provided new insights into the origins of the aromatic components of petroleum. The presence of a pronounced odd-over-even predominance in the C(subscript)25, C(subscript)27, and C(subscript)29 monodeuterated n-alkanes (CPI = 1.07), which corresponds to the odd-over-even predominance observed in the n-alkane components of unbiodegraded crude oils from the same basin, suggests that the n-alkyl side chains and the n-alkanes have a common source. Evidence is presented to support the hypothesis that the n-alkylaromatics are formed in part by geosynthetic processes involving alkylation of aromatic systems by electrophilic species such as carbocations and acylium ions formed from carboxylic acids. This hypothesis is then extended to ++ / explain the formation of other groups of compounds, including aromatic systems with isoprenoidal-, methylalkyl- and monoalkyl-branched side chains. Because isoprenoids, methylalkanes and alkylalkanes are well-known components of petroleum, these results suggest that these alkylaromatic components of petroleum may share a common source with the corresponding alkane components. It is suggested that aromatic unresolved complex mixtures arise due to the very large number of structurally related compounds present, which are formed by geosynthetic processes such as alkylation of aromatic rings.

A phytochemical survey to detect alkaloids was performed on extracts of 339 discrete plants parts from a total of 77 species from five genera of Elaeocarpaceae, including 30 species from Queensland, 38 from PNG, and nine from China. An alkaloid detecting reagent, bismuth (III) tetraiodide (Dragendorff's reagent) was used in a preliminary test for alkaloids, with positive ESIMS used to confirm the presence of alkaloids. A total of 35 extracts of various plant parts produced positive results with Dragendorff's reagent. Positive ESIMS detected alkaloids in only 13 of these extracts. Bismuth (III) tetraiodide was demonstrated to produce false positive results with the new non-alkaloidal poly-oxygenated compounds 112 and 113, which were purified from the extract of Sloanea tieghemii. Two new alkaloid producing species, Elaeocarpus habbeniensis, and E. fuscoides were detected from the survey. These species were chemically investigated for the first time. Two other previously investigated species, E. grandis and Peripentadenia mearsii, were also studied. A total of 16 alkaloids, 11 of which are new, were purified from the extracts of these four species. The novel pyrrolidine alkaloids habbenine (114) and peripentonine (123), were isolated from the leaves of E. habbeniensis and Peripentadenia mearsii, respectively. Both of these compounds were purified as inseparable mixtures of diastereomers. The new pyrrolidine alkaloid mearsamine 1 (124), and the novel amino alkaloid mearsamine 2 (125), were also purified from the leaves of P. mearsii. The known pyrrolidine alkaloid peripentadenine (81), was purified from the bark of P. mearsii. Peripentonine (123) was reduced to peripentadenine (81) upon reaction with Pd/C. Four aromatic indolizidine alkaloids were isolated from the extract of the leaves of E. fuscoides. One new compound, elaeocarpenine (122), was isolated from this New Guinean plant. Three known Elaeocarpus alkaloids, isoelaeocarpicine (62), elaeocarpine (60) and isoelaeocarpine (61) were also purified from E. fuscoides. Elaeocarpenine (122) was demonstrated to produce the epimeric compounds elaeocarpine and isoelaeocarpine via reaction with ammonia. The chemical investigation of the Queensland plant E. grandis by two separate purification procedures was performed. An SCX/C18 isolation protocol was used to purify the new indolizidine alkaloids grandisine C (127), D (126), and E (128), in conjunction with the known tetracyclic indolizidine isoelaeocarpiline (63). The second purification of E. grandis was achieved with the use of ammonia in an acid/base partitioning protocol. Grandisine F (129) and G (130), and compounds 131a and b were purified by this procedure, as were 63, 126 and 127. Grandisine F and G were proposed to be ammonia adducts of grandisine D (126). Compound 131a and b were isolated as a mixture of diastereomers. The reduction of grandisine D (126) with Pd/C yielded a mixture of isoelaeocarpine (61) and elaeocarpine (60), whereas the reduction of isoelaeocarpiline (63) produced isoelaeocarpine (61). All of the alkaloids isolated from the Elaeocarpaceae, except grandisine E (128) and 131a and b, were evaluated for binding affinity against the human ? opioid receptor. Every compound except mearsamine 2 (125) possessed a binding affinity of less than 100 ?M. The most active compounds were grandisine F (129), D (126), C (127), elaeocarpenine (122), isoelaeocarpine (61), isoelaeocarpiline (63) and peripentadenine (81). The IC50 values for these compounds were 1.55, 1.65, 14.6, 2.74, 13.6, 9.86 and 11.4 ?M, respectively. The SAR of the active compounds was compared. These observations indicated that the indolizidine alkaloids were more active than the pyrrolidine alkaloids, and a phenol or ketone at position C-12 of the indolizidine alkaloids produced better binding affinity. All of these alkaloids, except 129, were proposed to interact with two of the three binding domains of the ? opioid receptor. Grandisine F (129) was proposed to have a different mode of action than the other alkaloids in the series. Synthetic modifications to isoelaeocarpine (61) and peripentadenine (81) were investigated in an attempt to incorporate an extra aromatic group into these molecules. An extra aromatic group was proposed to provide increased binding affinity to the ? opioid receptor by interaction with the third binding domain of the receptor. Two different aromatic amines were successfully attached to peripentadenine (81) by a reductive amination reaction using NaBH(OAc)3 and a titanium catalyst. The reductive amination of the ketone in isoelaecarpine (61) with various amines and NaBH(OAc)3 or NaBH4 proved unsuccessful.

Immobilisation of functional entities, such as, enzymes, onto solid supports, as a means of facilitating their removal from the surrounding environment and subsequent regeneration has been in practice for many decades. This work focuses on the immobilisation and analysis of three-walled (pendant armed), cyclen based receptor complexes immobilised onto a silica surface for the purpose of sequestering aromatic anions from aqueous solution: Si-GPS-[Cd(Trac)](ClO4)2, Si-GPS-[Cd(DiPTrac)](ClO4)2, and Si-GPS-[Cd(TriPTrac)](ClO4)2 were the immobilised receptors used. Initially, synthesis of a three-walled model receptor, [Cd(TracHP12)](ClO4)2, that is not bound to silica yet mimics the properties of the silica anchored receptor complexes with a hydroxypropyl pendant arm was effected. Aromatic anion binding constant measurements were made on the model receptor using 1H NMR monitored titrations in DMSO-d6 which showed that, in comparison to the first generation four-walled receptors, the removal of one of the pendant arms did not affect the binding capability of the receptor's cavity significantly. It was shown that the binding strength correlated well with the pKa of the particular anion with, for example, p-hydroxybenzoate > m-hydroxybenzoate > o-hydroxybenzoate. The precursor to this receptor was then immobilised onto a silica surface and subjected to metal ion uptake studies to gauge its coordination properties with a number of divalent metal(II) ions: Cd(II), Pb(II), Zn(II), Cu(II) and Ca(II). The three Cd(II) coordinated receptor complexes mentioned above were then subjected to inclusion studies with a number of aromatic anions in aqueous conditions whereupon a reversal of the previously mentioned trend, i.e. o-hydroxybenzoate > m-hydroxybenzoate > p-hydroxybenzoate was observed. This indicated that the presence of water in the system changes the hydrogen bonding mode of the host-guest complexes, and was a major discovery arising from this work.

<p>Using a conditioning paradigm and an automated olfactometer, I investigated the olfactory sensitivity of five CD-1 mice for seven aromatic aldehydes. With two of the stimuli (3-phenylpropanal and canthoxal), the animals discriminated concentrations as low as 10 ppb (parts per billion) from the odorless solvent and with four of the stimuli (helional, cyclamal, lilial and lyral) they discriminated concentrations as low as 1 ppb, with single individuals even scoring better. All five animals yielded the by far lowest threshold value with bourgeonal and discriminated a concentration of 0.1 ppq (parts per quadrillion) from the odorless solvent. The detection threshold values for aromatic aldehydes were found to be affected by the type of functional groups and oxygen moiety attached to the benzene ring. A comparison of the present data with those obtained in other species found no clear correlation between olfactory sensitivity and the size of the olfactory receptor repertoire.</p>

Exposure to polycyclic aromatic hydrocarbons such as benzo[a]pyrene (B[a]P) has been determined to be a risk factor for various forms of human cancer. PAH DNA adducts have been shown to cause mutations, but carcinogenesis is also accompanied by alterations in gene expression. Inhibiting individual cytochrome P450s could clarify the interaction of P450s and other enzymes in the activation of polycyclic aromatic hydrocarbons to DNA binding intermediates. Phosphorodiamidate morpholino oligomers (PMOs), a class of antisense agents were targeted against cytochrome P450 1A1 (CYP1A1) and cytochrome P450 1B1 (CYP1BI). No significant inhibition of enzyme activity or expression was observed with any PMO used as measured by ethoxyresorufin-O-deethylase (EROD) activity and immunoblots. It was demonstrated that BPDE may react with PMOs in vitro, and PMOs may be segregated in lysosomes, blocking their efficacy. Nonspecific effects by the PMO on CYP1A1 activity were observed. These observations indicate multiple confounding effects in the use of PMOs for this purpose. Many of the genes regulated by histone deacetylases are involved in proliferation, cell function, and differentiation, and HDAC inhibitors are of great interest in cancer research. To probe epigenetic regulation of CYP1A1, MCF-7 cells were treated with two HDAC inhibitors, suberoylanilide hydroxamic acid (SAHA) and trichostatin A (TSA). SARA and TSA increased EROD activity and in RT-PCR. SARA and TSA reduced B[a]P induced CYP1A1 and CYP1B1 mRNA levels. B[a]P DNA binding was not significantly altered by SAHA or TSA treatment. To assay global protein expression changes after treatment with PAR, MCF-7 cells were treated with B[a]P, DB{a,1]P, coal tar extract (SRM 1597) and diesel exhaust extract (SRM 1975), Proteins were separated by two-dimensional electrophoresis, and analyzed using PDQuest. Spots of interest were excised and identified by matrix assisted laser desorption/ionization time of flight time of flight mass spectroscopy. Alterations in expression of heat shock proteins, cytoskeletal proteins, DNA associated proteins, and glycolytic and mitochondrial proteins were observed. Universally increased expression was observed for tubulin alpha and myosin light chain alkali, cyclophilin B, heterogeneous nuclear riboprotein B1, and alpha enolase. Additional proteins exhibiting change in expression included histone H2A.1, heat shock protein 70-2, galectin-3, nucleoside diphosphate kinase, ATP synthase, and electron transfer flavoprotein. / Graduation date: 2004