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Purpose This paper aims to analyse the effect of different polylactic acid (PLA) colours used on fused deposition modelling (FDM), considering the product finishing quality produced with the same process conditions. Design/methodology/approach The methodology adopted was to design a virtual modelling object and three-dimensional (3D) print it with FDM with different PLA colours (natural, green and black), using the same parameters. 3D scanning and scanning electron microscopy was used to analyse the model finishing of each sample. Fourier-transform infrared spectroscopy analysis, thermogravimetric analysis and dynamic mechanical analysis were used to characterize the material and verify if the colour affected its thermal behaviour. Findings Findings showed that different PLA colours lead to distinct 3D printed finishings under the same process conditions. Thermal analysis showed a reason for the printing finishing difference. The degradation temperatures and the glass temperatures vary depending on the PLA colour. This affects the FDM working temperature. Originality/value This study will contribute to improving the finishing quality of 3D printed products by collaborating to the determination of its process conditions.

Introduction: This work aims to pre-operatively manufacture custom-made low-cost implants and physical models ('biomodels') of fractured skulls. The pre-operative manufacturing of biomodels and implants allows physicians to study and plan surgery with a greater possibility of achieving the expected result. Customization contributes to both the esthetic and functional outcome of the implant because it considers the anatomy of each patient, while the low cost allows a greater number of people to potentially benefi t. Methods: From CT images of a fractured skull, a CAD model of the skull (biomodel) and a restorative implant were constructed digitally. The biomodel was then physically constructed with 3D Printing, and Incremental Sheet Forming (ISF) was used to manufacture the implant from a sheet of pure grade 2 titanium. Before cutting the implant's fi nal shape from a pre-formed sheet, heat treatment was performed to avoid deformations caused by residual stresses generated during the ISF process. Results: A comparison of the dimensions of the implant and its respective CAD biomodel revealed geometric discrepancies that can affect both functional and aesthetic effi ciency. Nevertheless, the fi nal shape preserved symmetry between the right and left sides of the skull. Electron microscopy analysis did not indicate the presence of elements other than pure titanium. Conclusions: Dimensional variability can be decreased with changes in the manufacturing process (i.e., forming and cutting) and the heating ramp. Despite biomedical characteristics, there was no contamination of the implant by harmful chemical elements. 3D Printing was effective in making the biomodel, enabling pre-operative planning and improving physicianpatient communication. Current results indicate that ISF is a process that can be used to obtain custom-made implants.

A metodologia da biônica parte da observação em diferentes escalas de materiais naturais e a consequente caracterização e aplicação dos ensinamentos da natureza em projetos de design e engenharia. Dentre os materiais naturais com propriedades mecânicas interessantes, encontra-se o bambu, pertencente ao grupo das gramíneas lenhosas, e caracterizado pela grande razão resistência por densidade. Dentre as características que conferem a resistência da planta encontra-se sua microestrutura, formada por feixes fibrosos longitudinais que envolvem elementos condutores ao longo do caule. A anatomia vegetal diz respeito ao estudo da microestrutura de plantas, onde são utilizados métodos clássicos de secionamento em amostras para observação microscópica dos tecidos e células constituintes. O designer deve estar na vanguarda de tecnologias para colaborar com o desenvolvimento de novas técnicas e aplicá-las na criação de novos produtos. Com o avanço das tecnologias 3D, novas técnicas de observação têm surgido para estudo de materiais, como a Microtomografia Computadorizada de Raios X (μCT) e a Modelagem por Deposição de Material Fundido (FDM). Nesse sentido, este trabalho apresenta os fundamentos básicos das técnicas de μCT e FDM, visando à caracterização da microestrutura interna do bambu. As técnicas são descritas e utilizadas para observação da microestrutura da planta, incluindo secionamento 3D do modelo virtual da amostra, obtido pelas imagens da μCT, e na representação das células constituintes. Por fim, o estudo apresenta o desenvolvimento de dois modelos físicos, impressos em FDM em escala 25:1, das regiões correspondentes aos feixes de fibras e aos elementos condutores. Os resultados permitiram visualizar em 3D a microestrutura da planta, auxiliando na compreensão de sua resistência, para aplicações em biônica. O estudo também apresentou a possibilidade de unir técnicas de μCT e FDM na geração de modelos virtuais e físicos para a observação aplicada à anatomia vegetal.

Telomerase is an enzyme responsible for telomere maintenance in almost all human cancer cells, but generally not expressed in somatic ones. Therefore, antitelomerase therapy is a potentially revolutionary therapeutic strategy, and the antitumor activity of telomerase inhibitors (TI) has been studied extensively recently, mainly for breast cancer. However, the effects expected from treatment with TI will appear only after many cell divisions, but the effects of this long-term approach are unknown. In this work, the consequences of 3120 h exposure of human breast cancer cells to TI MST-312 were investigated. MCF-7 cells were treated with MST-312 at a subtoxic concentration for a long time, and then cell morphology, viability, senescence, and proliferation were analyzed by phase-contrast microscopy, MTT assay, β-galactosidase test, and the trypan blue exclusion assay, respectively. Also, chromosomal stability was evaluated by classical cytogenetic analysis. The average length of telomeres and telomerase reverse transcriptase expression were accessed by real-time PCR and real-time RT-PCR, respectively. The MST-312 showed cytotoxic action and promoted telomere erosion, senescence, and chromosome aberrations, as expected, but in a small proportion. Nevertheless, the proliferation rate of the culture was not affected. As the main effect, the chronic exposure led to cell adaptation by overexpression of telomerase in response to the inhibitor, which is a potential cause of therapeutic failure and may be associated with a poor prognosis. In conclusion, despite the high therapeutic potential of TIs such as MST-312, the molecular outcomes of long-term exposure of tumors on these drugs have to be evaluated when considering their clinical application, especially for breast cancer treatment.