ISEL - Eng. Quim. Biol. - Comunicações
Permanent URI for this collection
Browse
Browsing ISEL - Eng. Quim. Biol. - Comunicações by Title
Now showing 1 - 10 of 74
Results Per Page
Sort Options
- Alternative sérum biomarkers of bacteraemia for intensive care unit patientsPublication . Araújo, Rúben; Von Rekowski, Cristiana; Bento, Luís; Fonseca, Tiago AH; Calado, CecíliaThe diagnosis of infections in hospital or clinical settings usually involves a series of time-consuming steps, including biological sample collection, culture growth of the organism isolation and subsequent characterization. For this, there are diverse infection biomarkers based on blood analysis, however, these are of limited use in patients presenting confound processes as inflammatory process as occurring at intensive care units. In this preliminary study, the application of serum analysis by FTIR spectroscopy, to predict bacteraemia in 102 critically ill patients in an ICU was evaluated. It was analysed the effect of spectra pre-processing methods and spectral sub-regions on t-distributed stochastic neighbour embedding. By optimizing Support Vector Machine (SVM) models, based on normalised second derivative spectra of a smaller subregion, it was possible to achieve a good bacteraemia predictive model with a sensitivity and specificity of 76%. Since FTIR spectra of serum is acquired in a simple, economic and rapid mode, the technique presents the potential to be a cost-effective methodology of bacteraemia identification, with special relevance in critically ill patients, where a rapid infection diagnostic will allow to avoid the unnecessary use of antibiotics, which ultimately will ease the load on already fragile patients' metabolism.
- Assessing T-lymphocyte activation by non-conventional metabolomicsPublication . Ramalhete, Luís; Calado, Cecília; Sancho, M. RosárioThe current methodologies to evaluate T-cell function are based on very laborious or/and expensive methods. Nevertheless, the assessment of the appropriate functioning of these cells is very important in the clinical context, namely as a diagnostic tool of T-cell alloreactivity in different hematological settings, solid organ transplantation and immunosuppressive therapy. In the present work, we evaluated the potential of Non-conventional Metabolomics (NM) based on FTIR spectroscopy, in the assessment of T lymphocyte function after mitogen activation by phytohemagglutinin (PHa).
- Assessing the molecular fingerprint of T lymphocyte activationPublication . Ramalhete, Luís; Calado, CecíliaMethods to evaluate Lymphocyte T function, are very important in clinical context, namely in patients with primary and secondary immunodeficiencies, bone marrow or hematopoietic stem cell transplantation, organ transplant and immunosuppressive therapy. However, the conventional monitoring techniques are based on laborious, expensive methods. In the present work, it was evaluated the potential of an infrared spectroscopy based-method, in the assessment of lymphocyte T function after mitogen activation. It was possible to discriminate, either by principal component analysis either by hierarchical cluster analysis of second derivative spectra of lymphocytes T, between resting T cells and activated T cells. The infrared spectroscopy-based method presents therefore a high potential for a new diagnostic tool of the T cell alloreactivity.
- Assessment of airborne nanoparticles emissions in the ceramic industryPublication . Esteves, H.; Gomes, João; M. Miranda, R.; Albuquerque, P.The aim of this study was to evaluate the occupational exposure to nanoparticles during the tasks performed in various jobs in the production processes of the national ceramic industry, analyze the collected data and seek to understand the specific occupational exposure situation of the workers in this sector. The study was developed in three different national production plants of ceramic, one of sanitary production, another of refractory bricks and another of ornamental ware (red paste). It is concluded that the values of occupational exposure to nanoparticles are high in all cases and that the nanoparticles are of very small size, with a strong capacity for alveolar penetration and, consequently, with a strong possibility of passing into the bloodstream, accumulating in the body.
- Biocatalytic synthesis of 1,2-naphtoquinones derivatives mediated by CotA-laccasePublication . Sousa, Ana Catarina; Santos, Iolanda; Martins, Lígia O.; Robalo, Maria PaulaCatalysis is one of the cornerstones of our present economy and society and the formation of value-added products is many times directly dependent on catalytic technologies. Nowadays, there is a growing need for development of green strategies involving clean organic reactions, which do not use harmful organic solvents and toxic reagents. Amongst the many options available for a synthetic organic chemist, biocatalysis has emerged as one approach with an excellent potential. Enzyme-catalyzed reactions offer a number of advantages compared to the traditional chemistry-catalyzed reactions and biocatalytic methods impart a “greener” character to the synthesis. Laccases (EC1.10.3.2, p-diphenol:dioxygen oxidoreductases) are multicopper oxidoreductive enzymes which have proven to be versatile and highly/efficient biocatalyst for the synthesis of different value-added chemicals and pharmaceuticals.1 A large number of 1,2-naphthoquinones derivatives have been reported to show antitumor activities by inhibit on of multiple enzymes.2 In addition to their anticancer properties, the naphthoquinone framework has significance in the development of new substances with promising biological activities in other diseases like neurodegenerative and viral diseases.3 The formation of naphthoquinone frameworks is quit-well documented and reported methods include various approaches using organic solvents and different chemical oxidants.4 In this context it is still a challenge to explore alternative and more sustainable synthetic routes for these compounds. As a part of our going research program for exploring the catalytic properties of CotA-laccase, a bacterial laccase isolated from the Bacillus subtilis, we describe in the present communication a practical and simple oxidative CotA-laccase mediated eco-friendly method to obtain 1,2-naphthoquinones derivatives using mild aqueous conditions and O2 as oxidant. All compounds were isolated in good yields and fully characterized by FTIR, NMR and ESI techniques.
- Biodegradable nanoparticles of alginate and chitosan as non-viral DNA oral delivery systemPublication . Gonçalves, Lídia M. D.; Cadete, Ana; Figueiredo, Lara; Calado, Cecília; Almeida, António J.The delivery of nucleic acids via the oral route involves overcoming barriers such as degradation of nucleic acids by low pH in the stomach, enzymatic degradation by DNases in the gut, crossing the physical barrier imposed by the mucus layer, cellular uptake, intracellular trafficking and nuclear uptake. As an oral drug carrier system chitosan nanoparticles are ideal, being mucoadhesive, interacting with the anionic sialic acid residues in mucin. In this study, plasmid DNA expressing a humanized secreted Gaussia Luciferase as reporter gene was encapsulated in alginate and chitosan nanoparticles, via a mild ionotropic gelation procedure with sodium tripolyphosphate as a counterion. The nanoparticle system here developed shows effective transfection of different human gastric epithelial cell lines with distinct cell differention. That was confirmed by the expression of luciferase in the different tested conditions, particularly the amount of encapsulated pGLuc.
- BioMol4Health_Biological chemistry: longevity in a cup of teaPublication . RESSAISSI, Asma; Fale, Pedro; Pacheco, Rita; Serralheiro, Maria LuisaInfusions have been studied on what concerns Alzheimer Disease, digestive process, diet cholesterol absorption and its biosynthesis inhibition. In the first two cases the inhibition of acetylcholinesterase (AChE) has been addressed. In the last two situations, an in vitro intestinal barrier has been simulated and the inhibition of the regulator enzyme (HMGR) in cholesterol biosysnthesis pathway has been studied. AChE has been the target of infusions inhibitory activity as its inhibition has been seen to improve cognition and global functioning1 in AD suffering people and to improve the gastrointestinal motility2. Given to lab animals the compounds presente in the infusions were able to reach the brain and inhibit the enzyme3. The effect of infusions on cholesterol bioavailability pointed out that some infusions were able to reduce cholesterol permeation4 and also to have some inhibitory activity5. Studies have indicated that phenolics are able to modify the cell proteome6. The infusions have also been shown to modify the amount of cholesterol transporter proteins in cell membrane and this maybe one of possible explanations for the reduction in cholesterol transport detected under the effect of infusions, on some people ando n simulated intestinal barrier.
- Biopharmaceuticals process monitoring based on infrared spectroscopy according to quality by designPublication . Sales, Kevin; Ribeiro Da Cunha, Bernardo; Calado, CecíliaEscherichia coli, the most common host microorganism to produce high value biopharmaceuticals, presents, however a natural variability due to high sensitivity towards small fluctuations of the cultivation environment. Therefore, to speed up the development process and to control this critical manufacturing step it is relevant to develop monitoring techniques allowing simultaneous characterization of the heterologous product synthesis and of the physiologic cell behavior under a variety of culture conditions. In the present work high-throughput mid-infrared (MIR) spectral analysis of dehydrated E. coli cell pellets and in situ near infrared (NIR) spectral analysis of the whole culture broth were compared to monitor the bioproduction of a model plasmid along recombinant Escherichia coli cultures. Good partial least square regression models were built, either based on MIR or on NIR spectral data. Besides being conducted in situ, NIR spectroscopy allowed building regression models as accurate as those obtained from the MIR setup, and even better models for estimating biomass and glycerol. However, MIR spectroscopy allows retrieving valuable biochemical and metabolic information along the cell culture, e.g. lipids, RNA, protein synthesis and turnover metabolism. This information contributed to better understand the complex interrelationships between the recombinant cell metabolism and the bioprocess environment. In resume, since NIR spectroscopy enables the in situ and real time monitoring without the risk of culture contamination, thus represents an appealing tool for control purposes specially at industrial (i.e. large-scale) productions. On the other hand, MIR spectroscopy is better suited for optimization processes, as it enables the analysis of hundreds of samples at ounce, and to acquire off line historical information along industrial production processes. Both monitoring techniques are therefore complementary, empowering optimization and control procedures more efficiently and quicker, according to the new regulatory framework based on Quality by Design.
- Calcium rich food wastes based catalysts for biodiesel productionPublication . Catarino, Maria Alice; Ramos, M.; Soares Dias, A. P.; Santos, Maria Teresa; Puna, Jaime; Gomes, JoãoBiodiesel produced from food wastes can help to solve several environmental issues: anthropogenic carbon emissions due to fossil fuels combustion and waste management. Biodiesel was produced using waste frying oils (WFO) and calcium rich food wastes such as mollusk, shrimp, eggs shells and cuttlebone to produce calcium based heterogeneous catalysts by calcination. The characterization of chalky white calcined powders by XRD showed diffraction lines typical of lime but some samples were slightly contaminated with calcite. The powders with low crystallinity showed high hydration rate presenting XRD features ascribable to nanocrystals of calcium hydroxide. The post reaction samples presented mainly lines due to calcium diglyceroxide and methoxide. Thermograms of used catalysts showed some weight loss of these calcium compounds, confirming the presence of such phases. All prepared catalysts were effective in catalyzing the methanolysis of soybean oil. A FAME yield around 96% was obtained after 2.5 h of reaction. When using WFO, the FAME yield was only 65% with simultaneous production of soap. The use of WFO and soybean oil mixtures attenuates the loss of catalytic performances. The obtained glycerin's presented a light color characteristic of heterogeneous catalyzed processes. FTIR spectra of glycerin's showed some features belonging to matter organic non glycerin and methanol. The catalyst reutilization without intermediate reactivation indicated that catalysts are somewhat stable. When WFO was used, the reused catalysts showed improved performance probably due to the formation of calcium diglyceroxide. Nevertheless, calcium diglyceroxide is bound to promote homogeneous catalysis and consequent deactivation.
- Calix[4]arene-carbazole-containing polymers synthesis, properties and thin films as molecular sensorsPublication . Costa, Alexandra; Barata, Patrícia; Fialho, Carina B.; Prata, José VirgílioCalix[4]arenes, an interesting bow-shaped macrocyles, have been explored due to their valuable properties, e.g. molecular recognition, proving outstanding complexability towards neutral and ionic guests of several origins. In this communication we report the synthesis and the chemosensing ability on the solid state of a new bicyclic calix[4]arene-based polymers integrating phenylene-ethynylene-carbazole units as fluorescente segments (Calix-OCP-PPE-CBZs), in the detection of several nitroanilines (NAs) in vapor phase.