Preparação e análise estrutural de complexos de samário

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Química e Biológica - Ramo de Bioprocessos

Calixarenos metálicos catalisadores de reacções orgânicas industriais sustentáveis

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Química e Biológica

Mn-II and Cu-II complexes with arylhydrazones of active methylene compounds as effective heterogeneous catalysts for solvent- and additive-free microwave-assisted peroxidative oxidation of alcohols

A one-pot template reaction of sodium 2-(2-(dicyanomethylene) hydrazinyl) benzenesulfonate (NaHL1) with water and manganese(II) acetate tetrahydrate led to the mononuclear complex [Mn(H2O)(6)](HL1a)(2)center dot 4H(2)O (1), where (HL1a) -= 2-(SO3-)C6H4(NH)=N=C(C N) (CONH2) is the carboxamide species derived from nucleophilic attack of water on a cyano group of (HL1) . The copper tetramer [Cu-4(H2O)(10)(-) (1 kappa N: kappa O-2: kappa O, 2 kappa N: k(O)-L-2)(2)]center dot 2H(2)O (2) was obtained from reaction of Cu(NO3)(2)center dot 2.5H(2)O with sodium 5-(2( 4,4-dimethyl-2,6-dioxocyclohexylidene) hydrazinyl)-4-hydroxybenzene-1,3-disulfonate (Na2H2L2). Both complexes were characterized by elemental analysis, IR spectroscopy, ESI-MS and single crystal X-ray diffraction. They exhibit a high catalytic activity for the solvent-and additive-free microwave (MW) assisted oxidation of primary and secondary alcohols with tert-butylhydroperoxide, leading to yields of the oxidized products up to 85.5% and TOFs up to 1.90 x 103 h(-1) after 1 h under low power (5-10 W) MW irradiation. Moreover, the heterogeneous catalysts are easily recovered and reused, at least for three consecutive cycles, maintaining 89% of the initial activity and a high selectivity.

Observações clínicas com um nôvo anti-helmíntico - triclorofenolpiperazina (CI-416) - no tratamento da ancilostomíase

O autor tratou 40 pacientes portadores de diversas helmintíases intestinais com um, nôvo sal de piperazina - Bis (2, 4, 5 - Triclorofenol) piperazina na dose única de 50 mg/kg de pêso corporal em jejum ou duas horas após a refeição matinal. Obteve com uma série de tratamento cura parasitológica em 25 pacientes (62,5%) infectados por Ancilostomídeos e mais 6 (15%) com um segundo curso da medicação, totalizando 31 pacientes curados parasitològicamente (77,5% dos casos). À tolerância ao produto foi boa, com exceção de dois casos (5%) que referiram vômitos logo após a ingestão da substância. Três enfermos relataram expulsão de exemplares adultos mortos de Ascaris lumbricoides pelas fezes. Com o esquema terapêutico empregado, o autor observou pequena atividade ãa droga com respeito à infecção por Ascaris lumbricoides e nula sôbre o Trichuris trichiura. Conclui que o nôvo antihelmíntico é bastante ativo contra a infestação determinada pelos Ancilostomídeos.

Organocatálise assimétrica: estudo mecanístico de reacções intramoleculares de aldol

Dissertação apresentada para obtenção do Grau de Doutor em Química, especialidade de Química Orgânica, pela Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia

Reologia de fluidos complexos

Dissertação efectuada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia de Materiais

Síntese e caracterização de polímeros electrocrómicos para possíveis aplicações em embalagens inteligentes

Dissertação apresentada à Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do Grau de Mestre em Tecnologia e Segurança Alimentar

High-temperature polymer based magnetoelectric nanocomposites

The use of polymer based magnetoelectric materials for sensing and actuation applications has been the subject of increasing scientific and technological interest. One of the drawbacks to be overcome in this field is to increase the temperature range of application above 100 ºC. In this way, a nanocomposite material composed by a mixture of two aromatic diamines, 1,3-Bis-2-cyano-3-(3 aminophenoxy)phenoxybenzene (diamine 2CN) and 1,3-Bis(3-aminophenoxy)benzene (diamine 0CN) and CoFe2O4 (CFO) nanoparticles was designed, fabricated and successfully tested for high temperature magnetoelectric applications. Results revealed that CFO nanoparticles are well distributed within the 0CN2CN polymer matrix and that the addition of CFO nanoparticles does not significantly alter the polyimides structure. The magnetization response of the composite is determined by the CFO nanoparticle content. The piezoelectric response of the 0CN2CN polymer matrix (≈11 pC.N-1) and the maximum α33 value (0.8mV.cm-1.Oe-1) are stable over time and decrease only when the composite is subjected to temperatures above 130 ºC. Strategies to further improve the ME response are also discussed.

Gd2O3: Eu3+/PPO/POPOP/PS composites for digital imaging radiation detectors

Polymer based scintillator composites have been produced by combining polystyrene (PS) and Gd2O3:Eu3+ scintillator nanoparticles. Polystyrene has been used since it is a flexible and stable binder matrix, resistant to thermal and light deterioration and with suitable optical properties. Gd2O3:Eu3+ has been selected as scintillator material due to its wide band gap, high density and visible light yield. The optical, thermal and electrical characteristics of the composites were studied as a function of filler content, together with their performance as scintillator material. Additionally 1wt.% of 2,5 dipheniloxazol (PPO) and 0.01wt.% of (1,4-bis(2-(5-phenioxazolil))-benzol (POPOP) were introduced in the polymer matrix in order to strongly improve light yield, i.e. the measured intensity of the output visible radiation, under X-ray irradiation. Whereas increasing scintillator filler concentration (from 0.25wt.% to 7.5wt.%) increases scintillator light yield, decreases the optical transparency of the composite. The addition of PPO and POPOP, strongly increased the overall 2 transduction performance of the composite due to specific absorption and re-emission processes. It is thus shown that Gd2O3:Eu3+/PPO/POPOP/PS composites in 0.25 wt.% of scintillator content with fluorescence molecules is suitable for the development of innovate large area X-ray radiation detectors with huge demand from the industries.

Comparison of the effect of two HMG CoA reductase inhibitors on LDL susceptibility to oxidation

OBJECTIVE: To study the differences between fluvastatin and pravastatin regarding LDL susceptibility to oxidation, plasma levels of total cholesterol (TC), HDL-C, LDL-C and triglycerides (TG) in hypercholesterolemic patients with established coronary heart disease (CHD). METHODS: A double-blind randomized parallel study was conducted that included 41 hypercholesterolemic outpatients with CHD treated at the Instituto de Cardiologia do Rio Grande do Sul. The inclusion criteria were LDL-C above 100 mg/dL and triglycerides below 400 mg/dL based on 2 measures. After 4 weeks on a low cholesterol diet, those patients that fullfilled the inclusion criteria were randomized into 2 groups: the fluvastatin group (fluvastatin 40 mg/day) and the pravastatin group (pravastatin 20 mg/day), for 24 weeks of treatment. LDL susceptibility to oxidation was analyzed with copper-induced production of conjugated dienes (Cu2+) and water-soluble free radical initiator azo-bis (2'-2'amidinopropanil) HCl (AAPH). Spectroscopy nuclear magnetic resonance was used for determination of lipids. RESULTS: After 24 weeks of drug therapy, fluvastatin and pravastatin significantly reduced LDL susceptibility to oxidation as demonstrated by the reduced rate of oxidation (azo and Cu) and by prolonged azo-induced lag time (azo lag). The TC, LDL-C, and TG reduced significantly and HDL-C increased significantly. No differences between the drugs were observed. CONCLUSION: In hypercholesterolemic patients with CHD, both fluvastatin and pravastatin reduced LDL susceptibility to oxidation.

NLRP3 inflammasome plays a key role in the regulation of intestinal homeostasis.

BACKGROUND:: Attenuated innate immune responses to the intestinal microbiota have been linked to the pathogenesis of Crohn's disease (CD). Recent genetic studies have revealed that hypofunctional mutations of NLRP3, a member of the NOD-like receptor (NLR) superfamily, are associated with an increased risk of developing CD. NLRP3 is a key component of the inflammasome, an intracellular danger sensor of the innate immune system. When activated, the inflammasome triggers caspase-1-dependent processing of inflammatory mediators, such as IL-1β and IL-18. METHODS:: In the current study we sought to assess the role of the NLRP3 inflammasome in the maintenance of intestinal homeostasis through its regulation of innate protective processes. To investigate this role, Nlrp3(-/-) and wildtype mice were assessed in the dextran sulfate sodium and 2,4,6-trinitrobenzenesulfonic acid models of experimental colitis. RESULTS:: Nlrp3(-/-) mice were found to be more susceptible to experimental colitis, an observation that was associated with reduced IL-1β, reduced antiinflammatory cytokine IL-10, and reduced protective growth factor TGF-β. Macrophages isolated from Nlrp3(-/-) mice failed to respond to bacterial muramyl dipeptide. Furthermore, Nlrp3-deficient neutrophils exhibited reduced chemotaxis and enhanced spontaneous apoptosis, but no change in oxidative burst. Lastly, Nlrp3(-/-) mice displayed altered colonic β-defensin expression, reduced colonic antimicrobial secretions, and a unique intestinal microbiota. CONCLUSIONS:: Our data confirm an essential role for the NLRP3 inflammasome in the regulation of intestinal homeostasis and provide biological insight into disease mechanisms associated with increased risk of CD in individuals with NLRP3 mutations. (Inflamm Bowel Dis 2010).

Effects of the peroxisome proliferator-activated receptor (PPAR)-gamma agonist pioglitazone on renal and hormonal responses to salt in diabetic and hypertensive individuals.

Aims/Hypothesis: Glitazones are powerful insulin sensitisers prescribed for the treatment of type 2 diabetes. Their use is, however, associated with fluid retention and an increased risk of congestive heart failure. We previously demonstrated that pioglitazone increases proximal sodium reabsorption in healthy volunteers. This study examines the effects of pioglitazone on renal sodium handling in individuals prone to insulin resistance, i.e. those with diabetes and/or hypertension. Methods: In this double-blind randomised placebo-controlled four-way crossover study, we examined the effects of pioglitazone (45 mg daily during 6 weeks) or placebo on renal, systemic and hormonal responses to changes in sodium intake in 16 individuals, eight with type 2 diabetes and eight with hypertension. Results: Pioglitazone was associated with a rapid increase in body weight and an increase in diurnal proximal sodium reabsorption, without any change in renal haemodynamics or in the modulation of the renin-angiotensin aldosterone system to changes in salt intake. A compensatory increase in brain natriuretic peptide levels was observed. In spite of sodium retention, pioglitazone dissociated the blood-pressure response to salt and abolished salt sensitivity in salt-sensitive individuals. Conclusions/Interpretation: Pioglitazone increases diurnal proximal sodium retention in diabetic and hypertensive individuals. These effects cause fluid retention and may contribute to the increased incidence of congestive heart failure with glitazones.

Characterization of the tonoplast Ca2+/H+ antiport system from maize roots.

The tonoplast calcium Ca2+/H+ antiport system of maize (Zea mays L. cv LG 11) roots was characterized using the ''pH jump'' technique in order to avoid interference from the tonoplast proton and Ca2+ pumps. Ca2+ uptake was recorded in the presence of different inhibitors and divalent ions. Chemical modification of amino acid residues of the antiport was used to elucidate the amino acid residues participating in the Ca2+ transport activity. The Ca2+/H+ antiport activity was found to be strongly inhibited by ruthenium red and verapamil, whereas diethylstilbestrol was less effective. Vanadate, erythrosin B, cyclopiazonic acid, bafilomycin, thapsigargin, N,N'-dicyclohexylcarbodiimide (DCCD) and 4,4'-diisothiocyanatostilbene-2,2'-disulfonate (DIDS) were without effect. Lanthanum and divalent ions were strongly inhibitory (Cd2+ > Mn2+ > Sr2+ > Ba2+). While reagents modifying sulfhydryl groups (N-ethylmaleimide and 5,5'-dithio-bis(2-nitrobenzoate)) did not affect the antiport activity, modification of trytophan residues (N-bromosuccinimide) was strongly inhibitory. We conclude that ruthenium red, verapamil, lanthanum and divalent cations directly inhibit Ca2+ uptake independent of the function of the proton and Ca2+ pumps. Moreover, the results of chemically modified amino acid residues suggest that sulfhydryl groups are not involved in Ca2+ transport, while tryptophan residues seem important for this translocation.

Phthalates in the NICU: Is it safe?

AIMS: As growing concerns exist regarding phthalate exposure, which could be teratogenic, carcinogenic or induce reproductive toxicity, we aimed to review the evidence of the risks due to the use of medical devices containing di(2-ethylhexyl)phthalate in hospitalized neonates. METHODS: We reviewed the literature, searching through medical literature databases (Pubmed, MEDLINE, EBM reviews, Cochrane database, Embase and Google Scholar) using the following keywords: phthalate, di(2-ethylhexyl)phthalate, newborn and neonate. RESULTS: We identified several associations with short and long term health dangers, mainly subfertility, broncho-pulmonary dysplasia, necrotising enterocolitis, parenteral nutrition associated cholestasis and neuro-developmental disorders. These data are based mainly on animal or observational human studies. CONCLUSION: Clinicians must be aware of the potential risks due to phthalate exposure in the NICU. Di(2-ethylhexyl)phthalate containing materials should be identified and alternative devices should be considered. There is a need to improve knowledge in this area.