298 research outputs found

    The adaptation of lipid profile of human fibroblasts to alginate 2D films and 3D printed scaffolds

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    Background: The investigation of the interactions between cells and active materials is pivotal in the emerging 3D printing-biomaterial application fields. Here, lipidomics has been used to explore the early impact of alginate (ALG) hydrogel architecture (2D films or 3D printed scaffolds) and the type of gelling agent (CaCl2 or FeCl3) on the lipid profile of human fibroblasts. Methods: 2D and 3D ALG scaffolds were prepared and characterized in terms of water content, swelling, mechanical resistance and morphology before human fibroblast seeding (8 days). Using a liquid chromatography-triple quadrupole-tandem mass spectrometry approach, selected ceramides (CER), lysophosphatidylcholines (LPC), lysophosphatidic acids (LPA) and free fatty acids (FFA) were analyzed. Results: The results showed a clear alteration in the CER expression profile depending of both the geometry and the gelling agent used to prepare the hydrogels. As for LPCs, the main parameter affecting their distribution is the scaffold architecture with a significant decrease in the relative expression levels of the species with higher chain length (C20 to C22) for 3D scaffolds compared to 2D films. In the case of FFAs and LPAs only slight differences were observed as a function of scaffold geometry or gelling agent. Conclusions: Variations in the cell membrane lipid profile were observed for 3D cell cultures compared to 2D and these data are consistent with activation processes occurring through the mutual interactions between fibroblasts and ALG support. These unknown physiologically relevant changes add insights into the discussion about the relationship between biomaterial and the variations of cell biological functions

    Bionics-based surgical training using 3D printed photopolymers and smart devices

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    Additive manufacturing technologies support the realization of surgical training devices using, typically, photopolymers-based materials. Unfortunately, the material jetting family, able to print a large range of soft and hard polymers, requires expensive machines and materials, which are not always available. On the other hand, vat polymerization fails in the resolution/volume ratio and in the mechanical properties reconstruction. Stereolithographic 3D printers, mostly used in dental surgery, make possible to realize cheap and sustainable models for training activity using only one material, reducing the possibility to obtain different mechanical characteristics. Moreover, the printed objects have to be treated (i.e. curing post-processing) in order to obtain the required performances, that could be preserved for long term storing. The aim of the proposed approach is to assure the surgeons' skills improvement through bionic-based surgical 3D printed models and smart devices, able to reproduce the same perception of a real surgical activity. We demonstrated how it is possible develop smart devices capable to take into account the same characteristics of different materials (i.e. bone and spongy bone) even if stored for a long time

    Long-term survival of stage I multiple myeloma given chemotherapy just after diagnosis or at progression of the disease: a multicentre randomized study

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    We conducted a randomized trial to evaluate whether melphalan-prednisone (MPH-P) treatment administered just after diagnosis improves survival of stage I multiple myeloma (MM). Between January 1987 and March 1993, 145 consecutive previously untreated patients with stage I MM were randomized between treatment with MPH-P (administered for 4 days every 6 weeks) just after diagnosis and treatment only at disease progression. Survival was not influenced by MPH-P treatment either administered just after diagnosis or at disease progression (64 vs 71 months respectively). Comparing the first with the second group the odds ratio of death is 1.17 (95% confidence interval 0.57–2.42;P = 0.64). Disease progression occurred within a year in about 50% of patients who were initially untreated. Response rate was similar in both groups, but duration of response was shorter in patients who were treated at disease progression (48 vs 79 months, P = 0.044). Patients actually treated at disease progression (34/70) survived shorter than those who had neither disease progression nor treatment (56 vs > 92 months;P = 0.005). Starting MPH-P just after diagnosis does not improve survival and response rate in stage I MM, with respect to deferring therapy until disease progression. However, patients with stage I MM randomized to have treatment delayed and who actually progressed and were treated had shorter survival than those with stable disease and no treatment. Biologic or other disease features could identify these subgroups of patients. © 2000 Cancer Research Campaig

    3D printed masks for powders and viruses safety protection using food grade polymers: Empirical tests

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    The production of 3D printed safety protection devices (SPD) requires particular attention to the material selection and to the evaluation of mechanical resistance, biological safety and surface roughness related to the accumulation of bacteria and viruses. We explored the possibility to adopt additive manufacturing technologies for the production of respirator masks, responding to the sudden demand of SPDs caused by the emergency scenario of the pandemic spread of SARS‐COV‐ 2. In this study, we developed different prototypes of masks, exclusively applying basic additive manufacturing technologies like fused deposition modeling (FDM) and droplet‐based precision extrusion deposition (db‐PED) to common food packaging materials. We analyzed the resulting mechanical characteristics, biological safety (cell adhesion and viability), surface roughness and resistance to dissolution, before and after the cleaning and disinfection phases. We showed that masks 3D printed with home‐grade printing equipment have similar performances compared to the industrial‐grade ones, and furthermore we obtained a perfect face fit by customizing their shape. Finally, we developed novel approaches to the additive manufacturing post‐processing phases essential to assure human safety in the production of 3D printed custom medical devices

    Distant echoes: evoking the soundscapes of the past in the radio documentary series Noise: a human history

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    This article asks whether radio can ever successfully evoke an accurate sense of the sound of the past. It does so through a reflective critical analysis of the 2013 BBC Radio 4 documentary series, Noise: A Human History, by its own writer and presenter. It explores how the ‘sound design’ of the series met the challenge of providing a longue durĂ©e history of sound without having recourse to authentic sound archive recordings for most of the period being covered. Through an analysis of key sequences, and by highlighting the significance of the broader context of production, it argues that it is possible for epistemologically valuable history to emerge, even via a medium that treats sound more as a device for evoking the imagination than as something possessing evidential status in itself. The article does this by invoking the series as a practical example of ‘historical acoustemology’, and by suggesting that in radio notions of subjectivity and perceptual mimesis are key to understanding the medium's success. In doing so, the article calls for a redefinition of the notion of the radiogenic – arguing for a move away from seeing ‘raw’ sound as the key ingredient of sound design, and towards greater attention to the influence of radio's other characteristics as a time-based, institutionally-produced mass medium
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