Browsing by Author "et al."
Now showing 1 - 4 of 4
Results Per Page
Sort Options
- Chemical Modification of Pachira aquatica Oil for Bio-Based Polyurethane Wood AdhesivesPublication . Silva, Emilly; Esteves, Bruno; Domingos, idalina; Almeida, Margarida Lopes de; Araújo, Bruno; Chaves, Izabella; Fassarella, Michelângelo; et al.The development of biomass-based adhesives has attracted interest as an alternative to petroleum-derived synthetic and potentially toxic adhesives. Pachira aquatica oil is a renewable raw material that can be incorporated into an MDI-based polyurethane system. In this study, the chemical composition and reactivity of P. aquatica oil were characterized using GC–MS, FTIR, and hydroxyl index measurements. The oil showed a predominance of saturated fatty acids, particularly methyl hexadecanoate (64.80%), derived from palmitic acid, and exhibited a low initial hydroxyl value. To enhance reactivity, the oil was transesterified with glycerol under different conditions, producing polyols with substantially increased hydroxyl values (412–769 mg KOH g−1 ), as confirmed by the intensified O–H and C–O bands in the FTIR spectra. The polyurethane adhesives were formulated from the selected polyols (P3 and P4) and evaluated at different NCO/OH ratios and pressing temperatures, using ABES shear tests. The highest ABES shear strength recorded was approximately 3.6 MPa, obtained for isocyanate indices between 0.8 and 1.0 and temperatures around 115 ◦C. Although this value represents the best performance among the tested conditions, it remains below the industrial benchmarks typically associated with the EN 205 standard (≈10 MPa). It is important to note that the ABES and EN 205 methods are not directly comparable due to differences in testing protocols. Nevertheless, the results indicate that, under the evaluated conditions, the adhesives exhibit limited mechanical performance and require further optimization.
- Exercise training decreases proinflammatory profile in Zucker diabetic (type 2) fatty ratsPublication . Teixeira-Lemos, Edite; Reis, F.; Baptista, S.; Pinto, R.; Sepodes, B.; Vala, Helena; Rocha-Pereira, P.; et al.Objective In the present study we evaluated the effect of exercise on the plasma levels of proinflammatory cytokines, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), and the anti-inflammatory molecule uric acid in the Zucker diabetic fatty (ZDF) rats that are more prone to develop type 2 diabetes mellitus. Methods Sixteen obese ZDF (Gmi fa/fa) rats (8 wk old, 228.40 ± 4.05 g) were randomly assigned to one of two groups (n = 8 each): an exercise-trained group and a sedentary one. In addition, 16 lean ZDF (Gmi +/+) rats (8 wk old, 199.00 ± 3.50 g) were subjected to identical sedentary and exercise conditioning (n = 8 each). Initially, rats swam 15 min/d (5 d/wk) in a 36°C bath. The exercise protocol was gradually increased by 15 min/d until a swimming period of 1 h/d (1 wk) was attained. Thereafter, rats swam 1 h/d, 3 d/wk, for an additional period of 11 wk. Rats were sacrificed 48 h after the last training period and the blood and pancreas were collected. Circulating levels of glucose, glycosylated hemoglobin, total cholesterol, triglycerides, insulin, uric acid, IL-6, and TNF-α were assessed. The concentrations of proinflammatory cytokines in the pancreas were also evaluated. Results In the diabetic ZDF (fa/fa) rats, exercise decreased hyperuricemia (−37.3%) and IL-6 and TNF-α levels (−16.9% and −12.7% respectively) and maintained the weight of the pancreas at near normal. Immunohistochemistry revealed a marked decrease in the expression of TNF-α and IL-6 in the pancreatic islet cells of ZDF (fa/fa) rats. Conclusion These results indicate that aerobic exercise is anti-inflammatory in nature.
- The Impact of Dual-Career Support Systems on Perceived Barriers Among European Student-Athletes with DisabilitiesPublication . Alejandro Leiva-Arcas; Raquel Vaquero-Cristóbal; Lourdes Meroño; María José Maciá-Andreu; Juan Alfonso García-Roca; Lucía Abenza-Cano; et al.; Pereira, Antonino: The aim of this study was to compare the socio-demographic, sporting characteristics and perceptions of student-athletes with disabilities of perceived barriers according to the state system of dual career support. Two hundred and twelve student-athletes with disabilities from two European countries with state centralisation in dual career-related education competences (n = 97) and three European countries with a laissez-faire system (n = 115) participated in this research. The perceptions of dual-career student-athletes (ESTPORT) questionnaire, the exercise benefits/barriers scale (EBBS), and the athletic identity measurement scale (AIMS) were used for data collection. Student-athletes in countries with laissez-faire systems perceived the difficulty of combining family care (p = 0.024; ES = 0.31), the time required to practice sport (p = 0.005; ES = 0.38), as well as the limitation of timetables (p < 0.001; ES = 0.52) and places that make sport practice possible (p < 0.001; ES = 0.73) as barriers. In conclusion, when a country’s educational system does not have structured support systems for dual careers, student-athletes perceive more barriers, regardless of their sporting level.
- Impacto de um programa de competências parentais no stress e competências de atenção plenaPublication . Santos, Ana Isabel Pratas Martins dos; Martins, Emília; Magalhães, Cátia; Mendes, Francisco; Fernandes, Rosina; et al.Objective: To analyze the impact of the Adults and Children Together Raising Safe Kids (ACT-RSK) Program in parenting skills, parenting stress, and mindfulness skills in a group of parents and children. Methods: This investigative intervention was based on the application of a pre-test and a post-test before and after the implementation of the ACT-RSK Program. The program consisted of eight weekly 90-minute sessions conducted with a sample of 22 parents from Central Portugal. The ACT-RSK Program questionnaires, Parenting Stress Index (PSI), Interpersonal Mindfulness in Parenting (IM-P) scale, and a socio-demographic questionnaire were used. A descriptive and inferential analysis (Wilcoxon) was conducted using the Statistical Package for Social Sciences (IBM SPSS, v. 24) with a 95% confidence interval. Results: Participants showed improvement from pre-test to post-test in all four program dimensions: Parenting Style (M=36.32±6.61 vs. M=48.50±4.31; p<0.01); Electronic Media (M=24.73±3.90 vs. M=30.73±2.90; p≤0.01); Child Development (M=55.18±11.82 vs. M=73.55±4.04; p≤0.01); and Parental Behavior (M=34.23±7.83 vs. M=43.05±2.81; p≤0.01). Likewise, significant improvement was seen in the Interpersonal Mindfulness in Parenting (IM-P) scale’s results (Z=-3.929, p=0.000) and in parenting stress, which decreased from a very high (91.59) to a medium level (74.45). Conclusion: Data show the ACT-RSK had a positive effect and improved study variables.