Browsing by Issue Date, starting with "2024-08-01"
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- Turning discarded blue shark (prionace glauca) skin into a valuable nutraceutical resourcePublication . Coscueta, Ezequiel R.; Fernandes, Nádia Cunha; Brassesco, María Emilia; Rosa, Ana; Almeida, André; Pintado, Maria ManuelaMarine-derived collagen, particularly from blue shark (Prionace glauca) skin, represents a sustainable resource for the nutraceutical industry, yet its effective utilisation remains underexplored. This study aims to optimise the enzymatic hydrolysis of blue shark skin collagen using alcalase and bromelain to enhance the bioactive properties of the resultant hydrolysates. We employed a multifactorial experimental design to determine the optimal hydrolysis conditions, assessing factors including enzyme concentration, pH, and temperature. The alcalase-treated hydrolysates demonstrated superior antioxidant and anti-inflammatory activities compared to those treated with bromelain, with increased solubilised proteins and a higher degree of hydrolysis. Notably, peptide profiles indicated that alcalase hydrolysates favoured the production of smaller peptides, suggesting enhanced bioavailability and digestive stability. In vitro gastrointestinal simulations demonstrated the functional stability of these peptides, indicating that while they undergo structural changes during digestion, their potential for gastrointestinal health remains significant. Our findings highlight the feasibility of converting blue shark skin, a commonly discarded by-product, into valuable nutraceutical ingredients, thus contributing to marine sustainability and waste reduction This research advances the biotechnological application of marine collagen and opens avenues for developing functional foods and pharmaceuticals.
- Impact of truncating diffusion MRI scans on diffusional kurtosis imagingPublication . Fouto, Ana R.; Henriques, Rafael N.; Golub, Marc; Freitas, Andreia C.; Ruiz-Tagle, Amparo; Esteves, Inês; Gil-Gouveia, Raquel; Silva, Nuno A.; Vilela, Pedro; Figueiredo, Patrícia; Nunes, Rita G.Objective Difusional kurtosis imaging (DKI) extends difusion tensor imaging (DTI), characterizing non-Gaussian difusion efects but requires longer acquisition times. To ensure the robustness of DKI parameters, data acquisition ordering should be optimized allowing for scan interruptions or shortening. Three methodologies were used to examine how reduced difusion MRI scans impact DKI histogram-metrics: 1) the electrostatic repulsion model (OptEEM); 2) spherical codes (OptSC); 3) random (RandomTRUNC). Materials and methods Pre-acquired difusion multi-shell data from 14 female healthy volunteers (29±5 years) were used to generate reordered data. For each strategy, subsets containing diferent amounts of the full dataset were generated. The subsampling efects were assessed on histogram-based DKI metrics from tract-based spatial statistics (TBSS) skeletonized maps. To evaluate each subsampling method on simulated data at diferent SNRs and the infuence of subsampling on in vivo data, we used a 3-way and 2-way repeated measures ANOVA, respectively. Results Simulations showed that subsampling had diferent efects depending on DKI parameter, with fractional anisotropy the most stable (up to 5% error) and radial kurtosis the least stable (up to 26% error). RandomTRUNC performed the worst while the others showed comparable results. Furthermore, the impact of subsampling varied across distinct histogram characteristics, the peak value the least afected (OptEEM: up to 5% error; OptSC: up to 7% error) and peak height (OptEEM: up to 8% error; OptSC: up to 11% error) the most afected. Conclusion The impact of truncation depends on specifc histogram-based DKI metrics. The use of a strategy for optimizing the acquisition order is advisable to improve DKI robustness to exam interruptions.
- The role of biotics as a therapeutic strategy for oral mucositis - a systematic reviewPublication . Frey-Furtado, Leonor; Magalhães, Inês; Azevedo, Maria João; Sampaio-Maia, BeneditaObjectives: Oral mucositis (OM) is an acute and highly prevalent side effect of cancer treatments. Currently, there is no effective strategy for its prevention or treatment. This systematic review aimed to assess the effectiveness of biotics used as a therapeutic strategy for the management of OM. Materials and Methods: The PRISMA checklist was followed and PubMed, Web of Science, and Scopus were screened for clinical and pre-clinical studies assessing the potential effects of biotics in OM. Inclusion criteria included in vivo studies related to oral mucositis evaluating the effect of biotics, and written in Portuguese, English, French, Spanish, or Dutch. The following exclusion criteria were used: systematic reviews and meta-analyses, reviews, case reports, opinion papers or comments, conference papers, letters without results, articles not related to oral therapy-induced mucositis or biotics, or in vitro articles that do not simulate oral mucositis. Results: From a total of 1250 articles retrieved, 9 were included in this systematic review. Four clinical studies reported a reduction in oral mucositis occurrence with Lactobacillus species (Lactobacillus casei and Lactobacillus brevis CD2) and Bacillus clausii UBBC07. In pre-clinical studies, Lactococcus lactis genetically modified and Lactobacillus reuteri reduced the severity of OM and Streptococcus salivarius K12 also decreased the size of the ulcers. Conclusion: The findings of this systematic review suggest that probiotic supplementation may potentially reduce the incidence of therapy-induced OM and decrease its severity in patients undergoing cancer treatment. However, the available evidence is marred by significant heterogeneity across studies.
- Career adapt-abilities scale: psychometric properties in a Lebanese samplePublication . Marques, Cátia; Oliveira, Íris M.; Vautero, Jaisso; Silva, Ana DanielaThis study examined the psychometric properties of the Career Adapt-Abilities Scale in a Lebanese sample. The study includes 236 Lebanese citizens (54.2% women; Mage = 30.14). Confirmatory factor analyses indicated that a hierarchical model yielded a good fit, with the CAAS measuring four distinct dimensions that can be combined in a higher-order career adaptability factor in a Lebanese sample. Results showed that the overall CAAS and sub-dimensions were highly reliable. Pearson correlation coefficients demonstrated that the CAAS’ scores were related to those of basic values and life satisfaction. The CAAS constitutes a promising measure to be used in Lebanese career counselling.
- Response aggregation to obtain truthful answers to sensitive questions: estimating the prevalence of illegal purchases of prescription drugsPublication . Gregori, Marco; Jong, Martin G. de; Pieters, RikThis research proposes a simple, new technique to obtain truthful answers to sensitive, categorical questions. The paired response technique (PRT) asks participants to merely report the sum of the answers to two paired questions, one baseline and one sensitive, with the answers to each question known only to the participants. The technique then statistically infers the prevalence of the sensitive characteristic and its potential drivers from the association of the baseline question with other questions in the survey. Monte Carlo simulations demonstrate the performance of the PRT under varying conditions. A representative survey (n =4,649) in the Netherlands about legal and illegal purchases of prescription drugs to enhance sexual performance reveals that 17.4% of the target population has purchased medication to enhance sexual performance at least once. In contrast, in a control group surveyed with direct questioning, only 5.1% admit having done so. The great majority of these individuals opt to purchase illegally. Two further empirical applications, respectively, in the United States and the United Kingdom, show that the PRT reduces cognitive and affective costs of survey participation compared with a state-of-the-art randomized response technique for categorical questions.
- Exploring the interplay between stress mediators and skin microbiota in shaping age-related hallmarks: a reviewPublication . Duarte, Marco; Pedrosa, Sílvia Santos; Khusial, P Raaj; Madureira, Ana RaquelPsychological stress is a major contributing factor to several health problems (e.g., depression, cardiovascular disease). Around 35% of the world’s population suffers from it, including younger generations. Physiologically, stress manifests through neuroendocrine pathways (Hypothalamic-Pituitary-Adrenal (HPA) axis and Sympathetic-Adrenal-Medullary (SAM) system) which culminate in the production of stress mediators like cortisol, epinephrine and norepinephrine. Stress and its mediators have been associated to body aging, through molecular mechanisms such as telomere attrition, mitochondrial dysfunction, cellular senescence, chronic inflammation, and dysbiosis, among others. Regarding its impact in the skin, stress impacts its structural integrity and physiological function. Despite this review focusing on several hallmarks of aging, emphasis was placed on skin microbiota dysbiosis. In this line, several studies, comprising different age groups, demographic contexts and body sites, have reported skin microbiota alterations associated with aging, and some effects of stress mediators on skin microbiota have also been reviewed in this paper. From a different perspective, since it is not a “traditional” stress mediator, oxytocin, a cortisol antagonist, has been related to glucorticoids inhibition and to display positive effects on cellular aging. This hormone dysregulation has been associated to psychological issues such as depression, whereas its upregulation has been linked to positive social interaction.
- Use of zinc oxide nanoparticles incorporated in polybutylene adipate terephthalate for food packaging. A focus on the impact in functional and physic-mechanical properties and on migration thereofPublication . Mendes, Ana Rita; Teixeira, Paula; Poças, FátimaPolybutylene adipate terephthalate (PBAT) and zinc oxide nanoparticles (ZnO NP) are among the most studied when it comes to address biodegradability and antimicrobial properties of materials for food packaging. This work presents a critical review of recent scientific literature with a focus on the impact in functional, physic-mechanical properties, compostability and on safety. The properties of the nanoparticles, such as morphology and size reported are reviewed together with the range of concentrations and methods of incorporation in the PBAT matrix. The effect on antimicrobial and antioxidant activities, thermostability, tensile and optical properties, as well as on mass transfer properties (barrier to moisture and gases and migration into foods) is discussed. The properties of PBAT/ZnO depend on particle size, shape and concentration of the ZnO NP. Particles with higher surface area and smallest size are reported to have the best performance (usually the spherical shaped). However, information on the morphology/size of the nanoparticle is often not provided. The typical concentration of NP incorporation ranges from 0.5 to 5%, but the interpretation of results regarding the effect of concentration is highly limited due to poor information on the statistical significance of the results, particularly for low concentrations of incorporation. Another limitation found regards the film production method, because most of the studies are based in films prepared by solvent-casting and not by extrusion. Antimicrobial activity is directly linked with the concentration of ZnO NP. Most studies applied in vitro experiments and not tests in real foods (in situ). Zinc migration can occur as the whole nanoparticle or in the ionic form. Studies indicate that migration of ZnO in the nano form is not expected if the nanoparticle is completely embedded in a polymeric matrix, which can be confirmed by some well-established techniques. However, studies focusing on migration from other matrices are lacking. Further investigations are needed to achieve a balanced incorporation of ZnO NP considering the particle activity and zinc migration and to evaluate the impact on safety when used in food packaging.
- Expectations, infections, and economic activityPublication . Eichenbaum, Martin; Matos, Miguel Godinho de; Lima, Francisco; Rebelo, Sergio; Trabandt, MathiasThis paper develops a quantitative theory of how people weigh the risks of infections against the benefits of engaging in social interactions that contribute to the spread of infectious diseases. Our framework takes into account the interrelated yet distinct ef- fects of public policies and private behavior on the spread of the disease. We evaluate the model using a novel micro data set on consumption expenditures in Portugal. The estimated model accounts for the cross-sectional consumption response of individuals of different ages at a given time, as well as the time-series response of consumption of the young and old across the first three waves of Covid. Our model highlights the critical role of expectations in shaping how human behavior influences the dynamics of epidemics.
- Digital influencers: catalysts for customer engagement and purchase intentionPublication . Hani, Ghamama; Haider, Syed Waqar; Raza, Aamir; Silva, Susana C.; Dias, Joana CarmoSocial Media Influencer (SMI) marketing represents a contemporary addition to the arsenal of digital advertising tools. Digital Content Creators are individuals who regularly share a variety of content, including visuals, audio recordings, and updates, across multiple social media platforms to shape consumers' perceptions of a brand and its products. The focus of this study is to examine how the credibility aspects of social media influencers (expertise, attractiveness, and trustworthiness) influence purchase intention and brand intimacy while also considering the mediating role of consumer engagement. This study used a quantitative, cross-sectional design with convenience sampling targeting social media-active individuals. Data were collected via a questionnaire distributed through email and social media, selecting participants who followed influencers. To gather data, 250 participants were engaged in an online questionnaire distributed via Google Forms. The findings indicate that the credibility dimensions of SMIs, particularly their attractiveness and trustworthiness, positively influence brand intimacy and purchase intention. Furthermore, consumer engagement serves as a critical mediator, connecting the authenticity of social media influencers with purchase intention and brand intimacy. In line with these results, it becomes evident that consumer engagement indirectly influences influencer credibility (trustworthiness and attractiveness), purchase intention, and brand intimacy. Notably, expertise does not exert any discernible impact on either brand intimacy or purchase intention. This study's outcomes provide valuable insights for marketing managers, underscoring the significance of partnering with influencers who possess a high level of trust within their respective marketing niches.
- The effectiveness of garlic extracts on biogenic amine formation by foodborne pathogens and fish spoilage bacteriaPublication . Yazgan, Hatice; Kuley, Esmeray; Ozogul, Yesim; Ozogul, Fatih; Bartkiene, Elena; Rocha, João MiguelImpacts of aqueous and ethanolic extracts of garlic were investigated in suppressing bacterial growth and biogenic amine (BA) formation by selected foodborne pathogens (Candida albicans, Salmonella paratyphi A, Escherichia coli and Staphylococcus aureus) and fish spoilage bacteria (Enterococcus faecalis, Photobacterium damselae and Pseudomonas luteola). The spread-plate method was used to monitor bacterial growth in histidine decarboxylase broth (HDB), whereas the rapid high-performance liquid chromatographic (HPLC) method was used for BA analysis. Bacterial growth and their ammonia and BA production were monitored using HDB. The results showed that bacterial growth on HDB was in the range from 9.13, for P. luteola, to 9.54 log CFU (colony-forming units) mL−1, for S. aureus and C. albicans. The presence of garlic extracts in HDB resulted considerably in lowering bacterial growth and BA formation (P < 0.05). The highest inhibitory activities of ethanolic and water garlic extracts were obtained for Gram-positive S. aureus with 1.4 and 1.5 logarithmic reduction on bacterial growth, followed by Gram-negative Salmonella Paratyphi A and E. coli. Application of garlic extracts, mainly ethanolic ones, showed a significant inhibitory effect on bacterial ammonia production, with 4-100-fold lower ammonia accumulation (P < 0.05). Bacteria produced all tested BAs, mainly dopamine, agmatine and tryptamine. The highest levels of histamine and tyramine (61.99 and 36.45 mg L−1) were produced by S. aureus. In the presence of aqueous or ethanolic garlic extracts, putrescine production by E. faecalis was around 110-fold lower than that of the control group. Results revealed that both garlic extracts are potent antimicrobials that can control the growth of foodborne pathogens and their harmful BA formation.