Publications

Abstract Swimming pool water requires disinfection in order to protect swimmers frompathogenic microorganisms. However, disinfection has also unintended consequences.Chlorine, the most commonly used disinfectant, reacts with the organic matter (natural,human and synthetic) present in the pool water producing disinfection by-products(DBPs) which are of primary concern. Currently, more than one hundred DBPs havebeen identified in swimming pools including, trihalomethanes, haloacids, halonitriles,haloaldeydes, haloketones, halonitromethanes, haloamines, haloamides, haloalcohols andhalogenated UV filters. Some of these DBPs have been detected in the blood, alveolar airand urine of swimming pool attendants. Exposure to DBPs has been linked to adversehealth effects, like increased risk of asthma and other respiratory diseases as well asbladder cancer. Very recently, the genotoxicity and mutagenicity of swimming poolwater have been assessed. It has been found that the mutagenicity of pool waters wassimilar to that of typical drinking water, indicating that the levels of mutagenic DBPs aresimilar in both waters.

Abstract Tamoxifen is a nonsteroidal antiestrogen that is currently and widely used in the treatment of breast cancer in all of its stages, in adjuvant therapy as a long-term suppressant of tumor recurrence and also as a chemopreventive agent in women that are in high risk of developing this type of estrogen-dependent cancer. From a toxicological and (bio)analytical point of view the knowledge of the metabolic pathways of a drug is found to be extremely important. So, in the present work the most important tamoxifen biotransformation steps were reviewed in the light of recent pharmacological data. This overview also includes the current controversy concerning tamoxifen DNA-damaging (genotoxic) versus non-genotoxic mechanisms. A special focus will be given to the putative application of electrochemical methods as a modern and reliable analytical tool for determination of tamoxifen and its metabolites. Moreover, the potential of DNA electrochemical sensors for detection of structural damage to DNA as a basis for toxicity screening is highlighted. Future prospects looking for the importance of developing new analytical methodologies are also discussed.

Abstract Luciferase is a powerful tool in bioanalysis. Several well-established methods employ luciferases, particularly firefly and Renilla luciferases, as reporter genes or biosensors in environmental, biomedical and biochemical research. These techniques have interesting features for the analyst such as sensitivity, specificity and reduced assay time. Nanochemistry and Nanotechnology are disciplines that are gaining much attention and evolving rapidly. They allow the development of custom-made nanomaterials with the desired properties, starting from conventional bulk materials. Recently, the coupling of nanomaterials such as carbon nanotubes, mesoporous silica nanoparticles, metallic nanoparticles and quantum dots with luciferases led to new or improved methodologies for analyte quantification and enhanced gene delivery strategies. One of the principal scopes is to modulate or alter luciferase's bioluminescence emission, either by stabilizing it or tuning it to longer wavelengths. This chapter aims to present state-of-art articles regarding new methods based on the coupling of luciferases to nanomaterials, along with a brief introduction to Nanoscience.

Abstract The asymmetric unit of the title compound, C18H21N3S, contains five molecules. The equivalent bond distances in the five molecules are in excellent agreement, the r.m.s. fit being within 0.007 angstrom. The five molecules are linked into a chain consisting of alternating pseudo-enantiomers by N-H center dot center dot center dot S hydrogen bonds supplemented by weak C-H center dot center dot center dot pi interactions. The action of a glide plane links the asymmetric unit into an extended chain. A polymorph of the title compound with one molecule in the asymmetric unit was reported by Braun et al. [Cryst. Res. Technol. (1988), 23, 35-39].

Abstract The thermodynamic study of the phase transition (fusion and sublimation) of 2,2':5',2 ''-terthiophene and 3,2':5',3 ''-terthiophene is presented. The obtained data is used to evaluate the (solid + liquid) and (solid + gas) phase equilibrium, and draw the phase diagrams of the pure compounds near the triple point coordinates. For each compound the vapour pressures at different temperatures were measured by a combined Knudsen effusion method with a vacuum quartz crystal microbalance. Based on the previous results, the standard molar enthalpies, entropies and Gibbs energies of sublimation were derived at T = 298.15 K. For the two terthiophenes and for 3,3'-bithiophene, the temperature, and the molar enthalpies of fusion were measured in a power compensated differential scanning calorimetry. The relationship between structure and energetics is discussed based on the experimental results, ab initio calculations and previous literature data for 2,2'-bithiophene and 3,3'-bithiophene. The 3,2':5',3 ''-terthiophene shows a higher solid phase stability than the 2,2':5',2 ''-terthiophene isomer arising from the higher cohesive energy due to positioning of the sulphur atom in the thiophene ring. The higher phase stability of 3,3'-bithiophene relative to 2,2'-bithiophene isomer is also related to its higher absolute entropy in the solid phase associated with the ring positional degeneracy observed in the crystal structure of this isomer. A significant differentiation in the crystal phase stability between isomers was found.

Abstract A new Knudsen effusion apparatus, enabling simultaneous gravimetric and quartz crystal microbalance mass loss detection, is described. This device allows the measurement of vapour pressures of small sample mass (50 to 100) mg over a wide temperature range (350 to 650) K using very short effusion time intervals. The performance of the apparatus was checked by measuring the vapour pressures of anthracene, benzanthrone, and 1,3,5-triphenylbenzene, between (0.1 and 1) Pa, over temperature intervals of 20 K. The derived standard molar enthalpies of sublimation and vapour pressures are in excellent agreement with the mean of the available literature values and with the recommended values. The new working methodology and design of this apparatus allows the measurement of high quality vapour pressure data due to: accurate temperature measurement and control; improvement in vacuum thermal contact between the effusion cell and the oven metal block; optimisation of the quartz crystal sensor head microbalance position; efficient temperature control of the quartz crystal microbalance head; accurate measurement of the resonance crystal frequency using an impedance circuit analyser methodology.

Abstract A set of three N-(diethylaminothiocarbonyl)benzimido derivatives was structurally characterized by solid state single crystal X-ray diffractometry. The temperature, standard molar enthalpies, and entropies of fusion were measured and derived using differential scanning calorimetry, including two more derivatives, whose structures have been published before. The compounds were further analysed by solid state FIR spectroscopy and the experimental FTIR spectra were compared with the calculated gas phase spectra at the B3LYP/6-311+G(d) level of theory. The structural results for the set were further used in the interpretation of thermophysical phase transition properties of the title compounds. A detailed molecular picture of N-(diethylaminothiocarbonyl)benzimido derivatives was obtained from Natural Bond Order (NBO) analysis. The combination of the applied methods reveals a deeper insight into the structures of this type of compound.

Abstract A series of 1-arylnaphthalenes and 1,8-diarylnaphthalenes were synthesized by the Suzuki-Miyaura cross-coupling methodology showing significant differentiation in the yields and selectivity between aryl rings with electron donating (higher yields), and electron withdrawing substituents (lower yields). These results strongly support the relation between the nucleophilicity of the boronate complex and its reactivity, and emphasize the importance of the transmetalation step in the overall efficiency of this cross-coupling reaction. The results obtained with non-symmetric 1,8-diarylnaphthalenes indicate preference for arylation of an already arylated species (the 1-aryl-8-bromonaphthalene intermediate) over mono-arylation of 1,8-dibromonaphthalene. Evidences for the existence of intramolecular Pd center dot center dot center dot pi and aromatic interactions in some Pd(II) complexes were found.

Abstract Nanobiotechnology refers to the ability to create and manipulate biological and bio-chemical materials, devices, and systems at atomic and molecular levels. Nano delivery systems hold great potential to overcome some of the obstacles in bio-pharmaceutical production, such as water soluble/insoluble pharmaceutical drugs and cosmetic ingredients, risks of toxicity, increasing bio-active efficacy, specificity, tolerability and its therapeutic index. Within nanoparticulate carriers, polymeric and lipid nanoparticles have risen to the forefront of bio-technology, having diverse applications in several fields of pharmaceuticals for oral, topical, ocular and intravenous administration, as well as in dermo-cosmetic products.