This work aimed to develop bioactive films based on alginate and κ-carrageenan that were incorporated with different concentrations 0, 0.2, 0.4, 0.8, 1 and 2% (w/v) of cinnamon essential oil (CEO). The films were crosslinked with a solution of calcium chloride obtained from limestone sludge through acid dissolution. The films were characterised according to their physical, mechanical, optical, antioxidant and antimicrobial properties. The best film formulation consisted of 1.5% total carbohydrate concentration, 0.45% glycerol and 0.4% (w/v) of Tween 20. The Fourier transform infrared Spectroscopy analysis confirmed the crosslinking between the polysaccharides and the incorporation of the CEO into the polymer matrix. The addition of the CEO increased the film thickness, reduced moisture content and water vapour permeability, yet it increased solubility, due to matrix disruption invoked by the oil droplets. SEM analysis showed that CEO affected film microstructure, with moderate concentrations leading to more homogeneous structures. In terms of the mechanical properties, CEO incorporation reduced stiffness and yield strength whilst increasing film flexibility, showcasing a plasticising effect. The films were colourless and transparent; moreover, none of the samples exhibited absorbance in the visible region (400–800 nm); however, all films showed absorption in the UV region. The incorporation of the CEO into the films provided antioxidant activity. Particularly, the sample containing 2% CEO had the highest activity, with values of 97.5 ± 0.77% and 75.9 ± 1.82% in the ABTS and DPPH, respectively. Overall, these results suggest that the developed films have promising potential as sustainable food packaging materials with enhanced antioxidant functionality, although further optimisation is needed to improve antimicrobial performance and validate their effectiveness in real food packaging systems.

The limestone quarrying and processing industry generates huge amounts of waste, with limestone sludge being one of the most prevalent and challenging by-products. This study aims to evaluate the potential of limestone sludge as a sustainable secondary raw material for the mechanochemical synthesis of bioceramics, specifically hydroxyapatite (HA), for high-added-value applications in bone tissue engineering. High-energy milling is innovatively used as the processing route: dry sludge (functioning as the calcium source), a phosphate source, and water were milled with the aim of producing calcium phosphates (in particular, hydroxyapatite) via mechanosynthesis. The industrial sludge was thoroughly analyzed for chemical composition, heavy metals, and mineral phases to ensure suitability for biomedical applications. The mixture of reagents was tailored to comply with Ca/P = 1.67 molar ratio. Milling was carried out at room temperature; the milling velocity was 600 rpm, and milling time ranged from 5 to 650 min. Characterization by XRD, Raman spectroscopy, and SEM confirmed the progressive transformation of calcite into hydroxyapatite through a metastable DCPD intermediate, following logarithmic reaction kinetics. The resulting powders are fine, homogeneous, and phase-pure, demonstrating that mechanosynthesis provides a low-cost and environmentally friendly pathway to convert limestone waste into functional bioceramic materials. This suggests that Moleanos sludge is a viable and sustainable source to produce tailored calcium phosphates and confirms mechanosynthesis as a cost-effective and reliable technology to activate the low-kinetics chemical reactions in the CaCO3-H3PO4–H2O system. This work highlights a novel circular economy approach for the valorization of industrial limestone sludge, turning a difficult waste stream into a high-value, sustainable resource.

There is great interest in the use of ceramics for dental restoration due aesthetic similarity to natural teeth.Dental applications also demand adequate mechanical and tribological properties.Namely, the restoration material must not wear out easily and must not lead to abnormal enamel wear of the antagonist tooth.In the present work ceramic composites were developed by slip casting of tailored Al2O3/Zr2O formulations containing ZrO2 in the form of submicrometric or of nanoparticles.After sintering sample surface was characterized by scanning electron microscopy and profilometry; hydrophilicity was evaluated using the sessile drop method.Wear behaviour was assessed by reciprocating pin-on-plate tests in artificial saliva, using molar and pre-molar human teeth as pins and samples of the produced materials as cusps.Commercial dental zirconia was used as reference material.High consolidation of composites was attained, with density values ranging from 95.8 %TD to 99.9 %TD.Samples containing submicrometric zirconia present uniform reinforcement distribution and small porosity.Samples containing nanomicrometric zirconia show irregular zirconia agglomerates with micrometric dimension and higher porosity.Wear measurements show that ceramic wear is not significant, while cusps wear is strongly dependent of the opposing ceramic surface counterface roughness and porosity.Attained results suggest that dental wear can be reduced if highly polished zirconia/alumina composites are used instead of zirconia.

Calcium phosphates were produced by mechanosynthesis, using eggshell, H3PO4 and 6-83 wt%-H2O. Mixtures were milled at 600 rpm during 0.5-12 h. Resulting calcium phosphates occur within specific milling domains; H2O concentration determines onset and stability of monophasic hydroxyapatite. Within the tested conditions, brushite is the first detected calcium phosphate precipitated from solution. In 6, 40 and 56 wt%-H2O, monetite intermediates brushite's transformation to hydroxyapatite; in 71 and 83 wt%-H2O transformation is direct. Hydroxyapatite formation is favoured at the H2O extremes tested, 6 and 83 wt%. CO2 build-up in the confined jar and nucleation-and-growth events during drying are possible obstacles upon control of morphology and composition of synthesised particles. The potential of chicken eggshell as direct biogenic source and the ability of high-energy milling as corresponding processing route to produce calcium phosphates was demonstrated. This signals a route for reliable production of brushite, monetite and hydroxyapatite. A preliminary milling map was built, allowing to obtain desired final product under specific milling conditions.

The use of processed limestone sludge as a crosslinking agent for films based on Na–alginate and ɩ-carrageenan/Na-alginate blends was studied. Sorbitol was tested as a plasticizer. The produced gel formulations included alginate/sorbitol and carrageenan/alginate/sorbitol mixtures, with tested sorbitol concentrations of 0.0, 0.5 and 1.0 wt%. The limestone sludge waste obtained from the processing of quarried limestone was converted into an aqueous solution of Ca2+ by dissolution with mineral acid. This solution was then diluted in water and used to induce gel crosslinking. The necessity of using sorbitol as a component of the crosslinking solution was also assessed. The resulting films were characterized regarding their dimensional stability, microstructure, chemical structure, mechanical performance and antifungal properties. Alginate/sorbitol films displayed poor dimensional stability and were deemed not viable. Carrageenan/alginate/sorbitol films exhibited higher dimensional stability and smooth and flat surfaces, especially in compositions with 0.5 wt% sorbitol. However, an increasing amount of plasticizer appears to result in severe surface cracking, the development of a segregation phenomenon affecting carrageenan and an overall decrease in films’ mechanical resistance. Although further studies regarding film composition—including plasticizer fraction, film optimal thickness and film/mold material interaction—are mandatory, the attained results show the potential of the reported ɩ-carrageenan/alginate/sorbitol films to be used towards the development of viable films derived from algal polysaccharides.

This article provides a comprehensive review of current evidence on the challenges and controversies in obstetrics, with a focus on shoulder dystocia, fetal monitoring, and the use of oxytocin in labor and delivery. A systematic search was conducted in three databases (Scielo, Google Scholar, and LILACS), resulting in the selection of 10 relevant studies for an integrative review. The studies encompassed various research methodologies, including systematic reviews, cohort studies, clinical trials, qualitative studies, and narrative reviews. The findings provided important insights into the investigated topics, including risk factors associated with shoulder dystocia, effectiveness of fetal monitoring, comparison of oxytocin use protocols, women’s experiences with shoulder dystocia, obstetric complications, controversies surrounding oxytocin use, incidence of shoulder dystocia, and utilization of fetal monitoring. These findings contribute to a better understanding of these topics and may guide clinical practice towards safer and more effective obstetric care. However, further research is needed to fill existing knowledge gaps and inform evidence-based decision-making in obstetrics.

Herpes zoster is a viral disease that can cause neurological complications in adults. In this integrative literature review, 15 scientific articles published in the last five years were analyzed to explore the main topics related to neurological complications of herpes zoster in adults. The topics covered include epidemiology, vaccination, risk factors, treatment, impact on quality of life, and multidisciplinary approach. Herpes zoster has an increased incidence in the elderly and immunocompromised individuals, and is associated with a higher risk of stroke. Vaccination is an effective strategy for preventing the disease and its complications, such as postherpetic neuralgia. Risk factors such as advanced age and severe pain during the acute episode are associated with the development of postherpetic neuralgia. Corticosteroids are an effective treatment option for reducing the risk of this complication. Herpes zoster and postherpetic neuralgia can have a significant impact on patients’ quality of life, especially in the physical and emotional aspects. A multidisciplinary approach involving healthcare professionals from different fields is essential for comprehensive and effective care.

The current work aims to develop high solid load zirconia pastes without organic binder additives, for the robocasting of dental structures. The effect of the amount of Dolapix CE64 dispersant on the stabilisation of zirconia aqueous suspensions was first tested. The determined optimal amount of dispersant was then used to produce pastes with zirconia concentration in the 80−90 wt% range. Pastes were further studied regarding rheological behaviour and printability. The most printable were used to produce parallelepiped blocks by robocasting; slip casting samples were also produced for comparison. Density, surface roughness, porosity, hardness and toughness of both types of samples were assessed after sintering. Finally, a model molar tooth was produced by robocasting and sintered.

This paper provides an in-depth analysis of the rehydration behaviour of recycled cement, obtained from thermal activation of waste cementitious materials. Phases' early age composition and development in pastes produced with recycled cement were followed from 8 h to 28 days and compared to those of Portland cement paste of similar composition. Characterisation was carried out using isothermal calorimetry, thermogravimetry, X-ray diffraction with Rietveld analysis, nuclear magnetic resonance spectroscopy, scanning electron microscopy and mechanical testing. The most significant hydration rate of recycled cement occurred after 24 h; corresponding calorimetric curves revealed a longer induction period than Portland cement pastes and a late acceleration peak after 30 h of hydration. Thermal analysis and microscopy observation showed that AFm phases in recycled cement paste developed at as early as 8 h. The alpha'H-C2S polymorph was identified through X-ray diffraction as the main phase present in anhydrous recycled cement. Rietveld analysis indicated a more significant reaction rate of this polymorph between 1 and 3 days, similarly to C3S in Portland cement paste at 28 days. The lower amount of the less reactive beta-C2S phase in recycled cement paste than in Portland cement paste appears to have led to slightly higher degree of hydration of the former at 28 days. However, the total volume of long-term hydrates was lower in recycled cement paste. A C/S ratio of 1.73 was estimated for alpha'H-C2S and nuclear magnetic resonance suggest that a similar type of C-S-H was formed in both pastes.

Learn&Fly is an Erasmus+ project aimed to demystify and to crack STEM subjects to youngsters by showing their importance and application in aeronautics. Concepts in physics and maths are explained by engagement in the construction of an aircraft, aimed to compete in a flight contest. Students must envisage, design, draw and calculate the craft, simulate its flight, make necessary design adjustments, and build it. In its first year the project attracted 121 students, between 17-21 years old; 19.5% were girls. Students work on the glider was accompanied by lectures in physics, materials, and technologies. A questionnaire was used to quantify students’ perception on project usefulness. Results show that students considered the project to be effective in improving STEM skills and career awareness, and very effective in improving soft skills. This is expected to result from the stimulating, hands-on STEM learning environment that provided access to contents, tools, and activities not usually available to high school students from the partaking countries.

Bone tissue engineering (BTE) is centered around the fabrication of scaffolds for the active treatment of large, critical-sized bone defects [...]

Lithium-Tin (Li-Sn) alloys are an attractive solution for plasma facing components of nuclear fusion reactors and have received considerable attention regarding lithium-ion batteries [...]

This paper studies the effects of glycerol plasticizers and/or alginate, pectin, and carboxymethylcellulose polysaccharides on the mechanical and physical properties of porphyran-based films to evaluate the films’ ability to be used as food packaging. Films were characterized in terms of their composition, microstructural and morphological features, thermal properties, water interaction, and mechanical performance. All films are homogeneous, transparent, and slightly brownish in color. The structures are amorphous and crosslinked, showing the films’ thermoset nature. Moisture content and water solubility depend on the second polysaccharide added to the porphyran, but they both increase with the addition of glycerol to the formulations; water vapor permeability is strongly affected by the second polysaccharide in the formulation. The films display stiff and brittle mechanical behavior, but ductility increases significantly in formulations containing glycerol plasticizers. The barrier and mechanical performance values of the materials produced were found to be lower than those reported for commercial food packaging. The formulations containing glycerol displayed lower water vapor permeability values, ranging from 2.98 for porphyran/carboxymethylcellulose/glycerol to 6.65 mm·g·d−1·m−2·kPa−1 for porphyran/alginate/glycerol films. All films, except porphyran/glycerol and porphyran/alginate/glycerol, had ultimate tensile strengths above 10 MPa—the threshold value that ensures that a package is ductile enough to withstand handling and forming operations. Furthermore, the porphyran/pectin/glycerol and porphyran/carboxymethylcellulose/glycerol films displayed sufficiently high ductility values of 2.94 and 3.10%, respectively. These results indicate that the studied porphyran/pectin/glycerol and porphyran/carboxymethylcellulose/glycerol formulations have a combination of physical and mechanical properties that ensure adequate film integrity and function through the complete food packaging supply chain. The results here reported represent an opportunity to extend the scope of porphyran films to applications in the dry food packaging industry.

Non-biodegradable plastic is one of the biggest environmental problems of our lifetime and, considering the present societal needs, it will get worse. Consequently, there is an urgent need to develop sustainable and renewable alternatives to plastic, such as plastic-like materials obtained from biodegradable polymers, namely sulfated polysaccharides, considered one of the most viable alternatives. There is also a need to obtain these materials in an environmentally and economically sustainable way. The hereby developed process of obtaining film-forming solutions from semi-refined porphyran (PorphSR) uses a green solvent (hot water) with a high extraction yield of semi-refined porphyran (26.66 ± 0.27%) in a reproducible way and with low levels of contaminants. The obtained semi-refined porphyran showed good antioxidant potential in all tests performed: HPSA (Δ0.066 ± 0.002), DPPH (2.23 ± 0.78%), FRAP (0.420 ± 0.014 eq. ascorbic acid µg mg−1 of extract) and ABTS (20.46 ± 0.90%). After being cast into films, the most notable antioxidant properties were those of the semi-refined porphyran in the DPPH, FRAP and ABTS assays and of the pectin, (PorphSR_PcT and PorphSR_PcT_Gly) in the HPSA assay. Morphologically, the films showed relatively homogeneous and low roughness surfaces. It is concluded that the described method to obtain semi-refined porphyran is feasible and reproducible, and that the developed films, mainly PorfP2_PcT_Gly, proved to be a potential candidate for non-biodegradable plastic substitutes.

Calcium phosphates can be used, individually or combined, to clinically promote bone healing [...]

The chemical modification of porphyran hydrocolloid is attempted, with the objective of enhancing its antioxidant and antimicrobial activities. Sulfated galactan porphyran is obtained from commercial samples of the red algae Porphyra dioica using Soxhlet extraction with water at 100 °C and precipitation with isopropyl alcohol. The extracted porphyran is then treated with modified L-tyrosines in aqueous medium in the presence of NaOH, at ca. 70 °C. The modified tyrosines L1 and L2 are prepared through a Mannich reaction with either thymol or 2,4-di-tert-butylphenol, respectively. While the reaction with 2,4-di-tert-butylphenol yields the expected tyrosine derivative, a mixture of products is obtained with thymol. The resulting polysaccharides are structurally characterized and the respective antioxidant and antimicrobial activities are determined. Porphyran treated with the N-(2-hydroxy-3,5-di-tert-butyl-benzyl)-L-tyrosine derivative, POR-L2, presents a noticeable superior radical scavenging and antioxidant activity compared to native porphyran, POR. Furthermore, it exhibited some antimicrobial activity against S. aureus. The surface morphology of films prepared by casting with native and modified porphyrans is studied by SEM/EDS. Both POR and POR-L2 present potential applicability in the production of films and washable coatings for food packaging with improved protecting characteristics.

Polymeric scaffolds provide several advantages when compared with other bone replacement and regenerating techniques. Namely, when compared with the current gold standard, bone autografts, there is no shortage of supply nor donor site morbidity. Contrarily to metallic implants, their mechanical properties are similar to those of cortical bone and they are biodegradable, therefore stress shielding is not expected to occur, and they will be gradually replaced by new bone tissue. Yet, there are still several challenges to overcome. After implantation scaffolds are subjected to dynamic loads, thus understanding polymeric scaffolds? fatigue behavior plays a major role on the design of better products. In this work PLA scaffolds were manufactured using 3D printing with optimized parameters. A total of six configurations were tested under static and dynamic load conditions. Static compression testing and numerical simulation showed good correlation. Numerical simulation provided a viable resource for scaffold design and innovation. Four different low-cycle fatigue loads were applied, during 3600 cycles with a frequency of 0.25 Hz. While under dynamic conditions, with a maximum stress of 24 MPa and R = 0.1, the apparent compressive modulus reached 973 MPa, due to pore collapse. Even after 3600 cycles no significant fatigue damage mechanisms were found on low porosity scaffolds, rendering them useful for trabecular bone replacement under dynamic conditions.

Bone transplant is still the gold standard approach when dealing with orthopedic trauma or disease. When this solution is not possible, scaffolding is a possibility provided by bone tissue engineering. To support the regeneration process, damaged bone tissue is removed and replaced by porous scaffold structures. In recent years, additive manufacturing has shown huge potential to produce scaffold structures with the required performance. In the current work, PLA scaffolds with different designs were 3D printed, using optimal manufacturing parameters. Scaffolds with three different porosity values were obtained by changing the filament offset from 571 to 1333 μm. A total of twelve designs were tested under monotonic and dynamic compression conditions. Numerical analysis showed good correlation with experimental results, allowing for a better assessment of scaffold mechanical behavior. Stress relaxation was measured on four different strain levels, assessing scaffold's behavior after implantation and consequent static response over time. Overall, orthogonal design provided better performance, due to improved material deposition. With lower porosity scaffolds equilibrium stress reached 24 MPa after 300 s relaxation time under 4% deformation, and the obtained equilibrium modulus was 428 MPa. Overall, attained results show that 3D printing with PLA can be applied in the manufacture of scaffolds for trabecular bone replacement.

The use of liquid Li-Sn alloys for nuclear fusion applications may be hampered by the high melting point of Li-rich intermetallics. Aiming to inhibit their formation, the blend of pure Li (as high as 15 at.%) with pure Sn was controlled via mechanical alloying at room temperature under a dry Ar atmosphere. The depth profiling of Li down to depths near 15-20 mu m was followed by nuclear reaction analysis, while elastic backscattering spectroscopy indicated the absence of O within the alloys. Elemental mapping using a nuclear microprobe evidenced the lateral spread of Li in the Sn matrix and identified Cr, Fe and Pb as the only contaminants with contents lower than 0.05 at.%. Despite the competing H-2(He-3,p)He-4, Li-6(He-3,p)Be-8, Li-7(He-3,p)Be-9 and Li-7(He-3,d)Be-8 nuclear reactions, retained amounts of deuterium in irradiated surfaces may be quantified with incident He-3(+) ion beams in the 0.7 MeV-1.0 MeV energy range.