Preservation of catechin antioxidant properties loaded in carbohydrate nanoparticles

Epigallocatechin gallate (EGCG), an antioxidant with several pharmacological and biological activities, was encapsulated in carbohydrate particles to preserve its antioxidant properties and improve its bioavailability. Gum arabic���maltodextrin particles loaded with EGCG (EGCG/P) were successfully produced by homogenization and spray-drying, with an EGCG loading efficiency of 96 �� 3%. Spray-dried particles are spherical or corrugated and polydisperse with diameters less than 20 m. The particles in aqueous suspension revealed two main populations, with mean average diameters of 40 nm and 400 nm. Attenuated total reflection-infrared spectroscopy (ATR-IR) confirmed that EGCG was incorporated in the carbohydrate matrix by intermolecular interactions, maintaining its chemical integrity. Atomic force microscopy imaging proved the particle spherical shape and size. The present study demonstrates that the carbohydrate matrix is able to preserve EGCG antioxidant properties, as proof of concept to be used as polymeric drug carrier.

Catalytic behavior of alkali-treated Pt/HMOR n-hexane hydroisomerization

Bifunctional Pt-HMOR catalysts were prepared by incipient wetness impregnation of various desilicated MOR obtained by alkaline treatment using NaOH concentrations ranging from 0.1 to 0.5 M. The zeolite structural changes upon modification were investigated by several techniques including powder X-ray diffraction,Al-27 and Si-29 MAS-NMR spectroscopy, N-2 adsorption, pyridine adsorption followed by infrared spectroscopy and the catalytic model reaction of m-xylene transformation. For low alkaline concentration the zeolite acidity is preserved, along with a slight increase of the volume correspondent to the larger micropores due to the removal of extra-framework debris already existent at the parent zeolite. At higher NaOH concentrations there is a significant loss of crystalinity and acidity as well as the formation of mesoporosity. The characterization of the metal function shows similar patterns for Pt-HMOR and Pt-M/0.1 samples, with Pt particles located mainly inside the inner porosity. In contrast, large Pt particles become visible at the intercrystalline mesoporosity of MOR crystals developed during the desilication treatments at severe alkaline conditions. The catalytic results obtained for n-hexane hydroisomerization showed an improved selectivity for dibranched over monobranched isomers for Pt-M/0.1 sample, likely due to the preservation of the support acidity and the slight enlargement of the micropores. This work is a new example in which the mesoporous development does not improve the catalytic efficiency of the zeolites, whereas mild alkaline desilication might be considered as an effective solution to produce customized catalysts with enhanced performance for a given application. (C) 2014 Elsevier B.V. All rights reserved.

Investigation of structural effects and behaviour of pseudomonas aeruginosa amidase encapsulated in reserved micelles

The acetohydroxamic acid synthesis reaction was studied using whole cells, cell-free extract and purified amidase from the strains of Pseudomonas aeruginosa L10 and A13 entrapped in a reverse micelles system composed of cationic surfactant tetradecyltrimethyl ammonium bromide. The specific activity of amidase, yield of synthesis and storage stability were determined for the reversed micellar system as well as for free amidase in conventional buffer medium. The results have revealed that amidase solutions in the reverse micelles system exhibited a substantial increase in specific activity, yield of synthesis and storage stability. In fact, whole cells from P. aeruginosa L10 and AI3 in reverse micellar medium revealed an increase in specific activity of 9.3- and 13.9-fold, respectively, relatively to the buffer medium. Yields of approximately 92% and 66% of acetohydroxamic acid synthesis were obtained for encapsulated cell free extract from P. aeruginosa L10 and A13, respectively. On the other hand, the half-life values obtained for the amidase solutions encapsulated in reverse micelles were overall higher than that obtained for the free amidase solution in buffer medium. Half-life values obtained for encapsulated purified amidase from P. aeruginosa strain L10 and encapsulated cell-free extract from P. aeruginosa strain AI3 were of 17.0 and 26.0 days, respectively. As far as the different sources biocatalyst are concerned, the data presented in this work has revealed that the best results, in both storage stability and biocatalytic efficiency, were obtained when encapsulated cell-free extract from P. aeruginosa strain AI3 at 14/0 of 10 were used. Conformational changes occurring upon encapsulation of both strains enzymes in reverse micelles of TAB in heptane/octanol were additionally identified by FTIR spectroscopy which clarified the biocatalysts performances.

Desenvolvimento de m��todos r��pidos para dete����o de drogas no meio aqu��tico

A vasta aplica����o de antibi��ticos em sistemas de aquacultura tem conduzido ao aparecimento de esp��cies microbianas resistentes, devendo ser evitada ou, se poss��vel, minimizada. A minimiza����o implica um controlo muito rigoroso das doses aplicadas, algo que s�� pode ser realizado se todo o processo anal��tico for simples, barato e puder ser implementado no local. O presente trabalho descreve para este efeito um sistema sensor constitu��do por papel quimicamente modificado, cujo procedimento anal��tico foi semelhante �� monitoriza����o de pH atrav��s das conhecidas tiras indicadoras de pH universal. O papel foi modificado com base em reac����es de monocamadas e assumiu uma colora����o t��pica ap��s contacto com o antibi��tico. A intensidade da colora����o estava tamb��m relacionada com a concentra����o desse antibi��tico. Como prova deste conceito, o sensor proposto foi desenhado tendo em vista a monitoriza����o de oxitetraciclina, um dos antibi��ticos utilizados neste contexto com elevada frequ��ncia. A modifica����o do papel foi baseada na altera����o qu��mica das unidades de glucose na matriz s��lida por reac����o covalente com reagentes apropriados. Foram utilizadas duas estrat��gias diferentes para este efeito: uma foi baseada em reac����es de tipo sol-gel e a outra em reac����o de adi����o nucle��fila. Posteriormente, o papel foi modificado com esp��cies met��licas capazes de mudar de cor na presen��a da oxitetraciclina. Estas modifica����es qu��micas foram avaliadas e optimizadas relativamente a v��rios par��metros, no sentido de promover uma varia����o de cor intensa face �� concentra����o de antibi��tico. Procedeu-se ainda ao controlo desta modifica����o por t��cnicas de espectroscopia de infravermelho. A varia����o de cor foi avaliada por compara����o visual, mas registada por imagem digital. Os materiais sensores preparados foram ainda caracterizados do ponto de vista do seu desempenho anal��tico. Inclu��ram-se aqui a identifica����o de uma rela����o linear entre coordenadas de cor e concentra����o, a atribui����o de uma gama de concentra����es capaz de fornecer uma resposta previs��vel e resposta cruzada face a outros antibi��ticos. Procedeu-se ainda �� aplica����o dos sensores numa amostra de ��gua ambiental dopada com antibi��tico. De uma forma geral, foi poss��vel estabelecer um processo simples de modifica����o de papel capaz de aferir a presen��a e a quantidade de tetraciclinas, mais concretamente a oxitetraciclina. O processo aqui estabelecido �� promissor, antevendo a concretiza����o de uma metodologia simples, barata e local para a monitoriza����o de anitbi��ticos em ��guas.

Desidrata����o/oxida����o seletiva de metanol recorrendo a catalisadores heterog��neos para a obten����o de biocombust��veis (DME e DMM)

Trabalho Final de Mestrado para obten����o do grau de Mestre em Engenharia Qu��mica e Biol��gica

Calixarenos met��licos catalisadores de reac����es org��nicas industriais sustent��veis

Trabalho Final de Mestrado para obten����o do grau de Mestre em Engenharia Qu��mica e Biol��gica

Molecular fingerprint of human gastric cell line infected by Helicobacter pylori

Helicobacter pylori infection represents a serious health problem, given its association with serious gastric diseases as gastric ulcers, cancer and MALT lymphoma. Currently no vaccine exists and antibiotic-based eradication therapy is already failing in more than 20% of cases. To increase the knowledge on the infection process diverse gastric cell lines, e.g. the adenocarcinona gastric (AGS) cell line, are routinely used has in vitro models of gastric epithelia. In the present work the molecular fingerprint of infected and non-infected AGS cell lines, by diverse H. pylori strains, was acquired using vibrational infrared spectroscopy. These molecular fingerprints enabled to discriminate infected from non-infected AGS cells, and infection due to different strains, by performing Principal Component Analysis. It was also possible to estimate, from the AGS cells molecular fingerprint, the effect of the infection on diverse biochemical and metabolic cellular status. In resume infra-red spectroscopy enabled the acquisition of infected AGS cells molecular fingerprint with minimal sample preparation, in a rapid, high-throughput, economic process yielding highly sensitive and informative data, most useful for promoting critical knowledge on the H. pylori infection process. �� 2015 IEEE.

Vertex component analysis: a geometric-based approach to unmix hyperspectral data

Hyperspectral remote sensing exploits the electromagnetic scattering patterns of the different materials at specific wavelengths [2, 3]. Hyperspectral sensors have been developed to sample the scattered portion of the electromagnetic spectrum extending from the visible region through the near-infrared and mid-infrared, in hundreds of narrow contiguous bands [4, 5]. The number and variety of potential civilian and military applications of hyperspectral remote sensing is enormous [6, 7]. Very often, the resolution cell corresponding to a single pixel in an image contains several substances (endmembers) [4]. In this situation, the scattered energy is a mixing of the endmember spectra. A challenging task underlying many hyperspectral imagery applications is then decomposing a mixed pixel into a collection of reflectance spectra, called endmember signatures, and the corresponding abundance fractions [8���10]. Depending on the mixing scales at each pixel, the observed mixture is either linear or nonlinear [11, 12]. Linear mixing model holds approximately when the mixing scale is macroscopic [13] and there is negligible interaction among distinct endmembers [3, 14]. If, however, the mixing scale is microscopic (or intimate mixtures) [15, 16] and the incident solar radiation is scattered by the scene through multiple bounces involving several endmembers [17], the linear model is no longer accurate. Linear spectral unmixing has been intensively researched in the last years [9, 10, 12, 18���21]. It considers that a mixed pixel is a linear combination of endmember signatures weighted by the correspondent abundance fractions. Under this model, and assuming that the number of substances and their reflectance spectra are known, hyperspectral unmixing is a linear problem for which many solutions have been proposed (e.g., maximum likelihood estimation [8], spectral signature matching [22], spectral angle mapper [23], subspace projection methods [24,25], and constrained least squares [26]). In most cases, the number of substances and their reflectances are not known and, then, hyperspectral unmixing falls into the class of blind source separation problems [27]. Independent component analysis (ICA) has recently been proposed as a tool to blindly unmix hyperspectral data [28���31]. ICA is based on the assumption of mutually independent sources (abundance fractions), which is not the case of hyperspectral data, since the sum of abundance fractions is constant, implying statistical dependence among them. This dependence compromises ICA applicability to hyperspectral images as shown in Refs. [21, 32]. In fact, ICA finds the endmember signatures by multiplying the spectral vectors with an unmixing matrix, which minimizes the mutual information among sources. If sources are independent, ICA provides the correct unmixing, since the minimum of the mutual information is obtained only when sources are independent. This is no longer true for dependent abundance fractions. Nevertheless, some endmembers may be approximately unmixed. These aspects are addressed in Ref. [33]. Under the linear mixing model, the observations from a scene are in a simplex whose vertices correspond to the endmembers. Several approaches [34���36] have exploited this geometric feature of hyperspectral mixtures [35]. Minimum volume transform (MVT) algorithm [36] determines the simplex of minimum volume containing the data. The method presented in Ref. [37] is also of MVT type but, by introducing the notion of bundles, it takes into account the endmember variability usually present in hyperspectral mixtures. The MVT type approaches are complex from the computational point of view. Usually, these algorithms find in the first place the convex hull defined by the observed data and then fit a minimum volume simplex to it. For example, the gift wrapping algorithm [38] computes the convex hull of n data points in a d-dimensional space with a computational complexity of O(nbd=2c��1), where bxc is the highest integer lower or equal than x and n is the number of samples. The complexity of the method presented in Ref. [37] is even higher, since the temperature of the simulated annealing algorithm used shall follow a log( ) law [39] to assure convergence (in probability) to the desired solution. Aiming at a lower computational complexity, some algorithms such as the pixel purity index (PPI) [35] and the N-FINDR [40] still find the minimum volume simplex containing the data cloud, but they assume the presence of at least one pure pixel of each endmember in the data. This is a strong requisite that may not hold in some data sets. In any case, these algorithms find the set of most pure pixels in the data. PPI algorithm uses the minimum noise fraction (MNF) [41] as a preprocessing step to reduce dimensionality and to improve the signal-to-noise ratio (SNR). The algorithm then projects every spectral vector onto skewers (large number of random vectors) [35, 42,43]. The points corresponding to extremes, for each skewer direction, are stored. A cumulative account records the number of times each pixel (i.e., a given spectral vector) is found to be an extreme. The pixels with the highest scores are the purest ones. N-FINDR algorithm [40] is based on the fact that in p spectral dimensions, the p-volume defined by a simplex formed by the purest pixels is larger than any other volume defined by any other combination of pixels. This algorithm finds the set of pixels defining the largest volume by inflating a simplex inside the data. ORA SIS [44, 45] is a hyperspectral framework developed by the U.S. Naval Research Laboratory consisting of several algorithms organized in six modules: exemplar selector, adaptative learner, demixer, knowledge base or spectral library, and spatial postrocessor. The first step consists in flat-fielding the spectra. Next, the exemplar selection module is used to select spectral vectors that best represent the smaller convex cone containing the data. The other pixels are rejected when the spectral angle distance (SAD) is less than a given thresh old. The procedure finds the basis for a subspace of a lower dimension using a modified Gram���Schmidt orthogonalizati on. The selected vectors are then projected onto this subspace and a simplex is found by an MV T pro cess. ORA SIS is oriented to real-time target detection from uncrewed air vehicles using hyperspectral data [46]. In this chapter we develop a new algorithm to unmix linear mixtures of endmember spectra. First, the algorithm determines the number of endmembers and the signal subspace using a newly developed concept [47, 48]. Second, the algorithm extracts the most pure pixels present in the data. Unlike other methods, this algorithm is completely automatic and unsupervised. To estimate the number of endmembers and the signal subspace in hyperspectral linear mixtures, the proposed scheme begins by estimating sign al and noise correlation matrices. The latter is based on multiple regression theory. The signal subspace is then identified by selectin g the set of signal eigenvalue s that best represents the data, in the least-square sense [48,49 ], we note, however, that VCA works with projected and with unprojected data. The extraction of the end members exploits two facts: (1) the endmembers are the vertices of a simplex and (2) the affine transformation of a simplex is also a simplex. As PPI and N-FIND R algorithms, VCA also assumes the presence of pure pixels in the data. The algorithm iteratively projects data on to a direction orthogonal to the subspace spanned by the endmembers already determined. The new end member signature corresponds to the extreme of the projection. The algorithm iterates until all end members are exhausted. VCA performs much better than PPI and better than or comparable to N-FI NDR; yet it has a computational complexity between on e and two orders of magnitude lower than N-FINDR. The chapter is structure d as follows. Section 19.2 describes the fundamentals of the proposed method. Section 19.3 and Section 19.4 evaluate the proposed algorithm using simulated and real data, respectively. Section 19.5 presents some concluding remarks.

Desenvolvimento de Anticorpos Pl��sticos para um Biomarcador do Cancro

O trabalho descrito compreende o desenvolvimento de um anticorpo pl��stico (MIP, do ingl��s Molecularly Imprinted Polymer) para o antig��nio carcinoembrion��rio (CEA, do ingl��s Carcinoembriogenic Antigen) e a sua aplica����o na constru����o de dispositivos port��teis, de tamanho reduzido e de baixo custo, tendo em vista a monitoriza����o deste biomarcador do cancro do colo-retal em contexto Point-of-Care (POC). O anticorpo pl��stico foi obtido por tecnologia de impress��o molecular orientada, baseada em eletropolimeriza����o sobre uma superf��cie condutora de vidro recoberto por FTO. De uma forma geral, o processo foi iniciado pela electropolimeriza����o de anilina sobre o vidro, seguindo-se a liga����o por adsor����o do biomarcador (CEA) ao filme de polianilina, com ou sem mon��meros carregados positivamente (Cloreto de vinilbenziltrimetilam��nio, VB). A ��ltima fase consistiu na electropolimeriza����o de o-fenilenodiamina (oPD) sobre a superf��cie, seguindo-se a remo����o da prote��na por clivagem de liga����es pept��dicas, com o aux��lio de tripsina. A efici��ncia da impress��o do biomarcador CEA no material polim��rico foi controlada pela prepara����o de um material an��logo, NIP (do ingl��s, Non-Imprinted Polymer), no qual nem a prote��na nem o mon��mero VB estavam presentes. Os materiais obtidos foram caracterizados quimicamente por t��cnicas de Infravermelho com Transformada de Fourier (FTIR, do ingl��s, Fourier Transform Infrared Spectroscopy) e microscopia confocal de Raman. Os materiais sensores preparados foram entretanto inclu��dos em membranas polim��ricas de Poli(cloreto de vinilo) (PVC) plastificado, para constru����o de sensores (biomim��ticos) seletivos a CEA, tendo-se avaliado a resposta anal��tica em diferentes meios. Obteve-se uma boa resposta potenciom��trica em solu����o tamp��o de ��cido 4-(2-hidroxietil)piperazina-1-etanosulf��nico (HEPES), a pH 4,4, com uma membrana seletiva baseada em MIP preparada com o mon��mero carregado VB. O limite de dete����o foi menor do que 42 pg/mL, observando-se um comportamento linear (versus o logaritmo da concentra����o) at�� 625 pg/mL, com um declive ani��nico igual a -61,9 mV/d��cada e r2>0,9974. O comportamento anal��tico dos sensores biomim��ticos foi ainda avaliado em urina, tendo em vista a sua aplica����o na an��lise de CEA em urina. Neste caso, o limite de dete����o foi menor do que 38 pg/mL, para uma resposta linear at�� 625 pg/mL, com um declive de -38,4 mV/d��cada e r2> 0,991. De uma forma geral, a aplica����o experimental dos sensores biomim��ticos evidenciou respostas exatas, sugerindo que os biossensores desenvolvidos prossigam estudos adicionais tendo em vista a sua aplica����o em amostras de indiv��duos doentes.

Development of new biomaterials based on liquid crystalline phases of cellulose derivatives

Disserta����o apresentada na Faculdade de Ci��ncias e Tecnologia da Universidade Nova de Lisboa para obten����o do Grau de Mestre em Engenharia Biom��dica

Effect of active components from Garlic on AGEs formation

Advanced glycation end-products are Maillard reaction products that are found in thermal processed food. This compounds are often referred as unhealthy for human diet, namely because of their capacity to form amino-acid dimers. There is a broad range of answers to get about how these products are formed, how they interact with the organism and how these reactions can be inhibited to prevent the referred effects. Some compounds from garlic are thought to be able to inhibit these reactions. This study using spectrophotometric, High Performance Liquid Chromatography-Tandem Mass Spectrometry (HPLC-MS/MS) and Fourier transformed infrared spectroscopy (FTIR) analysis, helps to understand better not only not only the effect of some compounds obtained from garlic, diallyl sulfide (DAS), diallyl disulfide (DADS) and diallyl trisulfide (DATS), on these AGEs production reaction, but also helped to understand better the reaction itself.

The materials, technique, conservation treatment and after-care of interior de um convento

Disserta����o apresentada na Faculdade de Ci��ncias e Tecnologia da Universidade Nova de Lisboa para a obten����o do grau de Mestre em Conserva����o e Restauro, especializa����o em pintura sobre tela

Electrochemical biosensor based on biomimetic material for myoglobin detection

A novel reusable molecularly imprinted polymer (MIP) assembled on a polymeric layer of carboxylated poly(vinyl chloride) (PVCsingle bondCOOH) for myoglobin (Myo) detection was developed. This polymer was casted on the gold working area of a screen printed electrode (Au-SPE), creating a novel disposable device relying on plastic antibodies. Electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and Fourier transform infrared spectroscopy (FTIR) studies confirmed the surface modification. The MIP/Au-SPE devices displayed a linear behaviour in EIS from 0.852 to 4.26 ��g mL���1, of positive slope 6.50 �� 1.48 (k�� mL ��g���1). The limit of detection was 2.25 ��g mL���1. Square wave voltammetric (SWV) assays were made in parallel and showed linear responses between 1.1 and 2.98 ��g mL���1. A current decrease was observed against Myo concentration, producing average slopes of ���0.28 �� 0.038 ��A mL ��g���1. MIP/Au-SPE also showed good results in terms of selectivity. The error% found for each interfering species were 7% for troponin T (TnT), 11% for bovine serum albumin (BSA) and 2% for creatine kinase MB (CKMB), respectively. Overall, the technical modification over the Au-SPE was found a suitable approach for screening Myo in biological fluids.

Forest fire detection with a small fixed wing autonomous aerial vehicle

In this work a forest fire detection solution using small autonomous aerial vehicles is proposed. The FALCOS unmanned aerial vehicle developed for remote-monitoring purposes is described. This is a small size UAV with onboard vision processing and autonomous flight capabilities. A set of custom developed navigation sensors was developed for the vehicle. Fire detection is performed through the use of low cost digital cameras and near-infrared sensors. Test results for navigation and ignition detection in real scenario are presented.

Planning, operations and data handling of planetary science missions

Disserta����o para obten����o do Grau de Mestre em Engenharia F��sica