Últimos itens adicionados do Acervo: Universidade do Porto

A Universidade do Porto (UP) é uma instituição de ensino superior pública portuguesa, fundada no dia 22 de Março de 1911 por decreto do Governo Provisório da República, mas com origens que remontam ao século XVIII.

Página 17 dos resultados de 39541 itens digitais encontrados em 0.008 segundos

‣ Assessment of dissolution profiles of brand and generic valproic acid formulations based on an experimental clean automatic approach

A. R. Pires; A. N. Araújo; C.M. Barbosa; M.C.B.S.M. Montenegro
Fonte: Universidade do Porto Publicador: Universidade do Porto
Tipo: Artigo de Revista Científica
Português

‣ Manipulação clínica - Dispensa clínica de medicamentos manipulados

Carlos Maurício Barbosa
Fonte: Universidade do Porto Publicador: Universidade do Porto
Tipo: Artigo de Revista Científica
Português

‣ Improvement of the inhibitory effect of xanthones on NO production by encapsulation in PLGA nanocapsules

Teixeira, M; Cerqueira, F; Barbosa, CM; Nascimento, MSJ; Pinto, M
Fonte: Universidade do Porto Publicador: Universidade do Porto
Tipo: Artigo de Revista Científica
Português
For the first time the inhibitory effect of xanthone and 3-methoxyxanthone on nitric oxide (NO) production by IFN-gamma/LPS activated J774 macrophage cell line is reported. A remarkable improvement of this effect promoted by encapsulation of these compounds in nanocapsules of Poly (DL-lactide-co-glycolide) (PLGA) is also demonstrated. A weak inhibitory effect of 3.6% on NO production by activated macrophages was observed for xanthone at the highest studied concentration (100 mu M). This effect was slightly higher for 3-methoxyxanthone at the same concentration, producing a reduction of 16.5% on NO production. In contrast, equivalent concentrations of xanthone and 3-methoxyxanthone incorporated in nanocapsules produced a significant decrease on NO production of 91.8 and 80.0%, respectively. Empty nanocapsules also exhibited a slight NO inhibitory activity, which may be due to the presence of soybean lecithin in the composition of the nanosystems. The viability of the macrophages was not affected either by free or nanoencapsulated xanthones. Fluorescence microscopy analysis confirmed that a phagocytic process was involved in the macrophage uptake of xanthone- and 3-methoxyxanthone-loaded PLGA nanocapsules. Phagocytosis might be the main mechanism responsible for the enhancement of the intracellular delivery of both compounds and consequently for the improvement of their biological effect.

‣ MOLECULARLY IMPRINTED POLYMERS FOR CONTROLLING DRUG RELEASE. PART 1: SYNTHESIS AND CHARACTERIZATION.

Margarita Domingues Sousa; Carlos Mauricio Barbosa
Fonte: Universidade do Porto Publicador: Universidade do Porto
Tipo: Artigo de Revista Científica
Português
MOLECULARLY IMPRINTED POLYMERS FOR CONTROLLING DRUG RELEASE. PART 1: SYNTHESIS AND CHARACTERIZATION. Molecularly imprinted polymers (MIPs) consist of synthetic macromolecular matrix, obtained through molecular imprinting-based methods that show ability to selectively recognize important biological molecules and its application in the drug delivery field is under development. In the present review the main aspects related to the synthesis and characterization of MIPs are studied. The fundamental variables participating in the synthesis process. Such as template molecule, functional monomers. cross-linking agents, solvents, and imprinting approaches are discussed, Moreover. the main available methods for MIPs chemical and morphological characterization are presented and the importance of the obtained information is discussed.

‣ Clear-Water Scour at Comparatively Large Cylindrical Piers.

Rui Lança; Cristina Fael; Rodrigo Maia; João Pedro Pêgo; António Heleno Cardoso
Fonte: Universidade do Porto Publicador: Universidade do Porto
Tipo: Artigo de Revista Científica
Português

‣ A família como foco de cuidados de enfermagem - aprendendo com o "family nursing game"

Carla Sílvia Neves da Nova Fernandes
Fonte: Universidade do Porto Publicador: Universidade do Porto
Tipo: Tese de Doutorado
Português

‣ Evaluation of the physical stability of SLN and NLC before and after incorporation into hydrogel formulations

Souto, EB; Wissing, SA; Barbosa, CM; Muller, RH
Fonte: Universidade do Porto Publicador: Universidade do Porto
Tipo: Artigo de Revista Científica
Português
Aqueous dispersions of lipid nanoparticles are being investigated as drug delivery systems for different therapeutic purposes. One of their interesting features is the possibility of topical use, for which these systems have to be incorporated into commonly used dermal carriers, such as creams or hydrogels, in order to have a proper semisolid consistency. For the present investigation four different gel-forming agents (xanthan gum, hydroxyethylcellulose 4000, Carbopol(R)943 and chitosan) were selected for hydrogel preparation. Aqueous dispersions of lipid nanoparticles-solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC)-made from tripalmitin were prepared by hot high pressure homogenization and then incorporated into the freshly prepared hydrogels. NLC differ from SLN due to the presence of a liquid lipid (Miglyol(R)812) in the lipid matrix. Lipid nanoparticles were physically characterized before and after their incorporation into hydrogels. By means of rheological investigations it could be demonstrated that physical properties of the dispersed lipid phase have a great impact on the rheological properties of the prepared semisolid formulations. By employing an oscillation frequency sweep test, significant differences in elastic response of SLN and NLC aqueous dispersions could be observed.

‣ Determination of clonixin in plasma and urine by reversed-phase high-performance liquid chromatography

Bica, A; Farinha, A; Blume, H; Barbosa, CM
Fonte: Universidade do Porto Publicador: Universidade do Porto
Tipo: Artigo de Revista Científica
Português
A reversed-phase high-performance liquid chromatographic method that enables the determination of clonixin in human plasma and urine samples is described. Recovery of the drug was over 87.6 and 80.7% for plasma and urine, respectively. The limit of quantitation of the method was established as 10 ng/ml in plasma and 20 ng/ml in urine samples, with RSDs of less than 11.1%. The applicability of the method was further assessed by determining the plasma concentrations time course of clonixin in six healthy volunteers after single oral dose administration of 150 and 300 mg of clonixin and Clonix,

‣ Comparative study between the viscoelastic behaviors of different lipid nanoparticle formulations

Souto, EB; Wissing, SA; Barbosa, CM; Muller, RH
Fonte: Universidade do Porto Publicador: Universidade do Porto
Tipo: Artigo de Revista Científica
Português
Application of drug substances to the skin for systemic absorption or action in a particular layer of the skin is a rather old approach. However, over the last years it has received much more attention, as a consequence of the development of new membrane-moderated and matrix reservoir devices. As new reservoir systems, solid lipid nanoparticles (SLN(TM)) and nanostructured lipid carriers (NLC(TM)) have been successfully tested for dermal application of different physicochemical substances. The knowledge obtained from theological investigations of these systems may be highly Useful for the characterization of the newly developed topical formulation. In the present study, an oscillation frequency sweep test was used for the evaluation of storage modulus (G), loss modulus (G"), and complex viscosity (eta*) of twelve different SLN and NLC formulations, over a frequency range from 0 to 10 Hz. The lipiclic aqueous dispersions were prepared using three different solid lipids (Softisan(R)138, Compritol(R)888, and stearyl alcohol) as matrix material. Miglyol(R)812, tocopherol, sunflower oil, and long-chain triacylglycerols were the chosen liquid lipids for NLC preparation. The objective of the present work was to investigate the effect of these different liquid lipids on the theological properties of aqueous dispersions of NLC as model systems. It was found that the liquid oil component of the formulation has a strong influence on the viscoelastic parameters...

‣ Polímeros com capacidade de reconhecimento molecular no controlo da libertação de fármacos

Sousa, M.D.; Barbosa, C.M.
Fonte: Universidade do Porto Publicador: Universidade do Porto
Tipo: Artigo de Revista Científica
Português

‣ A validated HPLC method for the assay of xanthone and 3-methoxyxanthone in PLGA nanocapsules

Teixeira, M; Afonso, CMM; Pinto, MMMM; Barbosa, CM
Fonte: Universidade do Porto Publicador: Universidade do Porto
Tipo: Artigo de Revista Científica
Português
This work relates the development and validation of a simple reversed-phase high-performance liquid chromatographic (HPLC) method for the analysis of xanthone (XAN) and 3-methoxyxanthone (3-MeOXAN) in poly(D,L-lactide-co-glycolide) (PLGA) nanocapsule formulations. This method does not require any complex sample extraction procedure. Chromatographic separation is made with a reversed-phase C18 column, using methanol-water (90:10, v/v) as a mobile phase at a flow rate of 1 mL/min. Identification is made by UV detection at 237 nm. The isocratic system operates at ambient temperature and requires 7 min of chromatographic time. The developed method is statistically validated according to United States Pharmacopoeia 25 and International Conference on Harmonization guidelines for its specificity, linearity, accuracy, and precision. The assay method proposed in this study is specific for XAN and 3-MeOXAN in the presence of nanocapsule excipients. Diode-array analyses confirm the homogeneity of XAN and 3-MeOXAN peaks in stressed conditions. Standard curves are linear (r > 0.999) over the concentration range of 0.4-2.5 and 1.0-5.8 ¿g/mL for XAN and 3-MeOXAN, respectively. Recovery from nanocapsules ranges from 99.6% to 102.8% for XAN and 98.8% to 102.4% for 3-MeOXAN. Repeatability (intra-assay precision) is acceptable with relative standard deviation values of 1.2% for XAN and 0.3% for 3-MeOXAN.

‣ Measuring and teaching light spectrum using Tracker as a spectrometer

Marcelo Rodrigues; Manuel Marques; Paulo Carvalho
Fonte: Universidade do Porto Publicador: Universidade do Porto
Tipo: Artigo de Revista Científica
Português

‣ A Simple Experiment to Explore Standing Waves in a Flexible Corrugated Sound Tube

P. Simeao Carvalho; Maria Eva Amorim; Teresa Delmira Sousa; Adriano Sampaio e Sousa
Fonte: Universidade do Porto Publicador: Universidade do Porto
Tipo: Artigo de Revista Científica
Português
Sound tubes, pipes, and singing rods are used as musical instruments and as toys to perform amusing experiments. In particular, corrugated tubes present unique characteristics with respect to the sounds they can produce; that is why they have been studied so intensively, both at theoretical and experimental levels.Experimental studies usually involve expensive and sophisticated equipment that is out of reach of school laboratory facilities. In this paper we show how to investigate quantitatively the sounds produced by a flexible sound tube corrugated on the inside by using educational equipment readily available in school laboratories, such as the oscilloscope, the microphone, the anemometer, and the air pump. We show that it is possible for students to study the discontinuous spectrum of sounds produced by a flexible corrugated tube and go even further, computing the speed of sound in air with a simple experimental procedure.

‣ Relationship between running economy and Kinematic parameters in recreational long-distance runners

Federico Pizzuto
Fonte: Universidade do Porto Publicador: Universidade do Porto
Tipo: Dissertação
Português

‣ Swimming and risk of asthma and allergies in Portuguese school aged children

Pinto, M.P.; Queirós, S.; Silva, Diana; Martins, C.; Madureira, J.; Oliveira Fernandes, E.; Padrão, Patrícia; Moreira, Pedro; Delgado, L.; Moreira, A.
Fonte: Universidade do Porto Publicador: Universidade do Porto
Tipo: Conferência ou Objeto de Conferência
Português
[resumo]; [abstract]

‣ Antitumor activity of xanthone derivatives: effects on the immune microenvironment

Viviana Vilar da Silva
Fonte: Universidade do Porto Publicador: Universidade do Porto
Tipo: Dissertação
Português

‣ Ciberjornalimo no Distrito de Santarém. A perspetiva do Jornalista

Rita Alexandra Ramos Inácio
Fonte: Universidade do Porto Publicador: Universidade do Porto
Tipo: Dissertação
Português

‣ Two experimental approaches of looking at buoyancy concept

J. Agostinho Moreira; A. Almeida; P. Simeão Carvalho
Fonte: Universidade do Porto Publicador: Universidade do Porto
Tipo: Artigo de Revista Científica
Português

‣ Hydration status and associated dietary factors in children

Neto, M.; Pinto, M.; Oliveira, A.; Padrão, Patrícia; Moreira, A.; Moreira, Pedro
Fonte: Universidade do Porto Publicador: Universidade do Porto
Tipo: Conferência ou Objeto de Conferência
Português
[resumo]; [abstract]

‣ Tourism Attraction Indexes: Empirical Evidence of their Relevance in the case of Portugal

Cátia Sofia Antunes Moreira Carvalho Marques
Fonte: Universidade do Porto Publicador: Universidade do Porto
Tipo: Dissertação
Português