In Vivo and in Vitro Evaluation of Chitosan Modified Bioactive Glass Paste for Wound Healing

In this thesis, chitosan (CS) improving the properties of bioactive glass (BG) paste for wound healing was studied. Based on the evaluation in vitro, the addition of CS neutralizes the...

Selective laser sintering of glass-ceramic bonds using a defocused Nd:YAG laser

Protecting miniature implantable electronics may require mm scale hermetic packages. Glass-ceramic bonding by selective laser sintering of glass sealing paste using a defocused Nd:YAG laser is presented. Glass sealing paste (FX11-036, Ferro) is screen printed onto alumina ceramic, clamped in contact with borosilicate glass, and laser treated while heating to 250°C. With the addition of defocusing and a heat source the glass paste reflowed and wetted both the alumina and coverslip surfaces, with an optimal effect between 10 mm and 15 mm defocusing. This method is promising to create electrically non-conductive hermetic seals at the mm scale.

O Castro de Salreu (Estarreja), um povoado proto-histórico no litoral do Entre Douro e Vouga

The Castro of Salreu, located in the municipality of Estarreja (Aveiro, center‑north of Portugal), is one of the most coastal proto‑historic settlements of the region between Douro and Vouga rivers, enjoying a privileged location on a meander of the river Antuã. The site has been the target, in recent years, of archaeological works that uncovered structures in two main areas, one of a housing nature and the other, corresponding to the defensive and delimiting structure of space. The five archaeological campaigns carried out allowed the collection of more than 35,000 ceramic fragments, some lithic artifacts, an engraved plaque, few metal objects and a set of more than two dozen glass paste beads. It is proposed that their occupation occurred between the 4th/3rd centuries BC and the change of the Age.

A Novel Fluoride Containing Bioactive Glass Paste is Capable of Re-Mineralizing Early Caries Lesions

White-spot-lesions (WSL) are a common complication associated with orthodontic treatment. In the current study, the remineralization efficacy of a BiominF® paste was compared to the efficacy of a fluoride gel. Methods: Orthodontic brackets were bonded to 60 human premolars buccal surfaces, which were covered with varnish, except a small treatment area (3 mm2). All specimens were challenged by a demineralization solution for 4 days. Specimens were assigned into 4 groups: BiominF® paste, Fluoride (4-min application), fluoride (twenty four hours application), and the control (n = 15). After cross-sectioning, enamel slabs having a thickness of approximately 100–120 μm were obtained. A TMR (Transverse Micro Radiography) technique was used to observe the sub-surface enamel lesions’ depth and mineral density, and their response to the remineralization protocols. One way ANOVA was used to analyze the results (α = 0.05). The top and the cross-sectional surfaces were observed using SEM/EDS. Results: Specimens treated with BiominF® paste showed significant decrease in delta z values, however lesion depth showed no significant difference when compared to the other three groups (p < 0.05). SEM/EDS observation showed the formation of crystal like structures on top of enamel demineralized surfaces, when treated with BiominF® paste. In conclusion BiominF® paste can be considered an effective remineralizing agent for white spot Lesions.

Mosaic and Trencadís in the Palau De La Música Catalana

Modernism has provided Catalonia with buildings of great artistic value, such as the Palau de la Música Catalana located in the heart of Barcelona. Its architect, Lluís Domènech i Montaner, approached ornamentation as a thorough integration of arts and crafts: ceramic is treated as the ¨key¨ element, decorating the entire building while coating and protecting its internal metallic structure at the same time.During Modernisme, the classic mosaic technique, based on the use of small tiles (or tesserae) made of ceramics or glass paste, incorporated a new method called trencadís (A procedure carried out using irregular pieces of tiles fragmented randomly and put together in an abstract way).

Prototyping and Production of High-temperature Power Electronic Substrates through Additive Manufacturing Processes

This paper reveals a study on Selective Laser Melting (SLM) as an alternative technology for producing power electronic substrates, and shows the possibility of producing a stable interface between alumina and copper through SLM technique. Additive Manufacturing (AM) has not yet been established in the manufacturing of electronic devices. The prevalent benefits of the generative manufacturing sector such as material efficiency, product customization/–flexibility, elimination of the usage of tools, constructional freedom and less process steps in contrast to the conventional fabrication methods of ceramic substrates for power electronic applications like DBC or AMB, are pointed out. Moreover, AM reduces energy costs due to the elimination of the necessary firing, etching and washing processes. The realized study focuses on the examination of adhesion strengths of copper structures, melted on different Al2O3 ceramics with and without pre-copper and -glass paste coating. The melting process was categorized for different laser parameters (1–3) based on the same energy input. Maximum shear values of the substrate probes reached were at about 30 N/mm2 for copper coated ceramic, and at 20 N/mm2 for conventional and glass paste coated substrates. All results were determined in a full factorial design of experiment (DoE) with 54 combinations and a sample size of six samples per parameter combination. Furthermore, several cross sections of the probes produced were illustrated to better understand the melting and joining behavior of the copper powder applied on the ceramic substrates. For improved mechanical adhesion, the ceramic substrates were roughened by laser radiation, with roughness values measured, and the cracking behavior of the exposed ceramics explained.