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- A suplementação com ácido fólico na gravidez: perceções e práticas clínicas na Área Metropolitana do PortoPublication . Silva, Carla; Pinto, Elisabete; Keating, Elisa
- Silk-based anisotropical 3D biotextiles for bone regenerationPublication . Ribeiro, Viviana P.; Silva-Correia, Joana; Nascimento, Ana I.; Morais, Alain da Silva; Marques, Alexandra P.; Ribeiro, Ana S.; Silva, Carla J.; Bonifácio, Grata; Sousa, Rui A.; Oliveira, Joaquim M.; Oliveira, Ana L.; Reis, Rui L.Bone loss in the craniofacial complex can been treated using several conventional therapeutic strategies that face many obstacles and limitations. In this work, novel three-dimensional (3D) biotextile architectures were developed as a possible strategy for flat bone regeneration applications. As a fully automated processing route, this strategy as potential to be easily industrialized. Silk fibroin (SF) yarns were processed into weft-knitted fabrics spaced by a monofilament of polyethylene terephthalate (PET). A comparative study with a similar 3D structure made entirely of PET was established. Highly porous scaffolds with homogeneous pore distribution were observed using micro-computed tomography analysis. The wet state dynamic mechanical analysis revealed a storage modulus In the frequency range tested, the storage modulus values obtained for SF-PET scaffolds were higher than for the PET scaffolds. Human adipose-derived stem cells (hASCs) cultured on the SF-PET spacer structures showed the typical pattern for ALP activity under osteogenic culture conditions. Osteogenic differentiation of hASCs on SF PET and PET constructs was also observed by extracellular matrix mineralization and expression of osteogenic-related markers (osteocalcin, osteopontin and collagen type I) after 28 days of osteogenic culture, in comparison to the control basal medium. The quantification of convergent macroscopic blood vessels toward the scaffolds by a chick chorioallantoic membrane assay, showed higher angiogenic response induced by the SF-PET textile scaffolds than PET structures and gelatin sponge controls. Subcutaneous implantation in CD-1 mice revealed tissue ingrowth's accompanied by blood vessels infiltration in both spacer constructs. The structural adaptability of textile structures combined to the structural similarities of the 3D knitted spacer fabrics to craniofacial bone tissue and achieved biological performance, make these scaffolds a possible solution for tissue engineering approaches in this area.
- Critical evaluation of commonly used objective functions to optimize overall quality and nutrient retention of heat-preserved foodsPublication . Silva, C.; Hendrickx, M.; Oliveira, F.; Tobback, P.Two objective functions—volume average retention and volume average cook-value—commonly used to optimize the overall quality and nutrient retention of heat-preserved foods, were studied and optimal processing conditions based on the two approaches were compared. Case studies from the literature were run and tested for the two objective functions. The influence of the decimal reduction time (at the reference temperature, Dref value) of the quality factor on the optimal processing temperature was evaluated. For high Dref values, e.g. for vitamins, the two objective functions give the same results and the Dref value has a minor influence on the optimum processing conditions. For low Dref values, such as for texture and colour, the optimal sterilization temperature is affected by this parameter and the use of volume average cook-value, as objective function, does not take this effect into account, which may result in underestimation of the optimal processing temperature.
- Storage stability of a safer ovos moles formulation: texture and microbiological assessmentPublication . Fundo, J.; Quintas, M.; Brandão, Teresa R. S.; Silva, C.
- Modulating cell adhesion to polybutylene succinate biotextile constructs for tissue engineering applicationsPublication . Ribeiro, Viviana P.; Almeida, Lília R.; Martins, Ana R.; Pashkuleva, Iva; Marques, Alexandra P.; Ribeiro, Ana S.; Silva, Carla J.; Bonifácio, Graça; Sousa, Rui A.; Oliveira, Ana L.; Reis, Rui L.Textile-based technologies are powerful routes for the production of three-dimensional porous architectures for tissue engineering applications because of their feasibility and possibility for scaling-up. Herein, the use of knitting technology to produce polybutylene succinate fibre-based porous architectures is described. Furthermore, different treatments have been applied to functionalize the surface of the scaffolds developed: sodium hydroxide etching, ultraviolet radiation exposure in an ozone atmosphere and grafting (acrylic acid, vinyl phosphonic acid and vinyl sulphonic acid) after oxygen plasma activation as a way to tailor cell adhesion. A possible effect of the applied treatments on the bulk properties of the textile scaffolds has been considered and thus tensile tests in dry and hydrated states were also carried out. The microscopy results indicated that the surface morphology and roughness were affected by the applied treatments. The X-ray photoelectron spectroscopy and contact angle measurements showed the incorporation of oxygen-containing groups and higher surface free energy as result of the surface treatments applied. The DNA quantification and scanning electron microscopy analysis revealed that these modifications enhanced cell adhesion and altered cell morphology. Generally, sodium hydroxide treatment altered most significantly the surface properties, which in turn resulted in a high number of cells adherent to these surfaces. Based on the results obtained, the proposed surface treatments are appropriate to modify polybutylene succinate knitting scaffolds, influencing cell adhesion and its potential for use in tissue engineering applications.
- Finely tuned fiber-based porous structures for bone tissue engineering applicationsPublication . Ribeiro, Viviana; Silva-Correia, Joana; Morais, Alain; Correlo, Vitor M.; Marques, Alexandra P.; Ribeiro, Ana; Silva, Carla; Durães, Nelson; Bonifácio, Graça; Sousa, Rui A.; Oliveira, Joaquim M.; Oliveira, Ana L.; Reis, Rui L.
- Influence of rotational speed on the statistical variability of heat penetration parameters and on the non uniformity of lethality in retort processingPublication . Smout, C.; Ávila, I.; Van Loey, A.M.L.; Hendrickx, M.E.G.; Silva, C.In a case study on white beans, the e ect of rotation on the statistical variability of heat penetration parameters and on the nonuniformity of lethality in industrial-scale retort processing was investigated. In addition, the in¯uence of process time on the nonuniformity of lethality was evaluated. No clear relation between the non-uniformity of the heating parameters and the rotational speed was observed. Rotation seemed to in¯uence process lethality variability throughout the retort by its e ect on non-uniformity in heating characteristics and in retort temperature. Absolute non-uniformity (i.e. standard deviation) increased with increasing holding time, whereas relative non-uniformity (i.e. coe cient of variation) decreased as holding time increases
- Optimizing thermal processes of conduction heated foods: generalized equation for optimal processing temperaturesPublication . Hendrickx, M.; Silva, C.; Oliveira, F.; Tobback, P.Optimal sterilization temperatures, for maximum surface quality retention, were calculated as a function of : (I)product propertles (thermal diffusivity and z.value) (II) processlng conditions Igeometry and dlmensions of the food, surface heat transfer coefficient, initial product temperature and retort come up time) and z-value (III) processing criteria (target- Fo.value). From this theoretical study generalized empirical relations relating optimal temperatures and all relevant variables were formulated and presented. Applications in classical canning are lllustrated in detail.
- The impact of folic acid supplementation on gestational and long term health: critical temporal windows, benefits and risksPublication . Silva, Carla; Keating, Elisa; Pinto, ElisabeteMaternal folic acid (FA) supplementation is one of the most popular nutritional interventions during pregnancy for its protective effect against neural tube defects (NTDs). The purposes of this review are: (a) to gather the current evidence regarding supplementation of maternal diet with FA and (b) to problematize the available literature in terms of dosages, critical temporal windows, and its potential benefits and risks. The expression (pregnancy OR fetus OR offspring OR mother) AND (“folic acid” AND supplementation) was searched on PubMed database, filtering for articles published from 2005 to 2014. Publications referring to FA supplementation during the periconceptional period or pregnancy in which there was a conclusion about the effects of isolated FA supplementation on pregnant woman, pregnancy or offspring were included. Of the initial 1182 papers, 109 fulfilled the inclusion criteria. The majority of the publications reported FA supplementation outcomes on offspring's health, with emphasis in NTDs, allergy/respiratory problems, cancer and behaviour problems. Some inconsistency is observed on the impact of FA supplementation on different outcomes, except for NTDs. It is also visible an increased concern about the impact of excessive supplementation, either in terms of doses or exposure's duration. In conclusion, there is a growing interest in FA supplementation issues. The protective effect of FA supplementation over NTDs has been confirmed, being the periconceptional period a critical window, and it is frequently suggested that allergy/respiratory outcomes arise from (excessive) FA supplementation particularly later in pregnancy. Further research on critical doses and time of exposure should be conducted.
- Optimal sterilization temperatures for conduction heating foods considering finite surface heat transfer coefficientsPublication . Silva, C.; Hendrickx, M.; Oliveira, F.; Tobback, P.Optimal sterilization temperatures are defined as the processing temperatures which result in a minimum surface cook-value after achieving the desired degree of sterility. They were calculated as a function of product heating rate, surface heat transfer coefficient, initial food temperature, heating medium come-up-time, z-value for the quality factor and target Fo-value. Different one-dimensional heat transfer shapes were considered. Compared to the other variables, initial temperature and heating medium come-up-time had little influence on optimal processing temperature. Regression equations were developed relating optimal temperatures with all relevant variables.