1,720,984 research outputs found
Un nuovo dispositivo (FAQ.FIX®) per il posizionamento di attacchi ortodontici in tecnica straight-wire.
No full textChapter 24: 3D-printed Soft Hydrogels for Cell Encapsulation
No full textRecent advances in 3D-printing with a combination of cell biology with materials science allowed the manufacturing of cell-encapsulated biomaterials to be used in tissue engineering. The main component of these bioprinted constructs is a bioink that requires its characteristics to be considered and tuned throughout the selection process. In this chapter, the focus is on the physico-chemical and biological requirements of the hydrogels being considered as bioinks with a deep investigation on the different crosslinking mechanisms that allow a stable hydrogel to be created during the bioprinting process. This chapter also describes the current focus areas for cell-encapsulated bioprinting highlighting the recent progress and limitations of the bioprinting to date, with a critical perspective on the future outlook
Plga membranes functionalized with gelatin through biomimetic mussel-inspired strategy
Full text linkElectrospun membranes have been widely used as scaffolds for soft tissue engineering due to their extracellular matrix-like structure. A mussel-inspired coating approach based on 3,4-dihydroxy-DL-phenylalanine (DOPA) polymerization was proposed to graft gelatin (G) onto poly(lactic-co-glycolic) acid (PLGA) electrospun membranes. PolyDOPA coating allowed grafting of gelatin to PLGA fibers without affecting their bulk characteristics, such as molecular weight and thermal properties. PLGA electrospun membranes were dipped in a DOPA solution (2 mg/mL, Tris/HCl 10 mM, pH 8.5) for 7 h and then incubated in G solution (2 mg/mL, Tris/HCl 10 mM, pH 8.5) for 16 h. PLGA fibers had an average diameter of 1.37 ± 0.23 μm. Quartz crystal microbalance with dissipation technique (QCM-D) analysis was performed to monitor DOPA polymerization over time: after 7 h the amount of deposited polyDOPA was 71 ng/cm2. After polyDOPA surface functionalization, which was, also revealed by Raman spectroscopy, PLGA membranes maintained their fibrous morphology, however the fiber size and junction number increased. Successful functionalization with G was demonstrated by FTIR-ATR spectra, which showed the presence of G adsorption bands at 1653 cm−1 (Amide I) and 1544 cm−1 (Amide II) after G grafting, and by the Kaiser Test, which revealed a higher amount of amino groups for G functionalized membranes. Finally, the biocompatibility of the developed substrates and their ability to induce cell growth was assessed using Neonatal Normal Human Dermal Fibroblasts
Insights into oxidative stress in bone tissue and novel challenges for biomaterials
Full text link\ua9 2021 Elsevier B.V.The presence of Reactive Oxygen Species (ROS) in bone can influence resident cells behaviour as well as the extra-cellular matrix composition and the tissue architecture. Aging, in addition to excessive overloads, unbalanced diet, smoking, predisposing genetic factors, lead to an increase of ROS and, if it is accompanied with an inappropriate production of scavengers, promotes the generation of oxidative stress that encourages bone catabolism. Furthermore, bone injuries can be triggered by numerous events such as road and sports accidents or tumour resection. Although bone tissue possesses a well-known repair and regeneration capacity, these mechanisms are inefficient in repairing large size defects and bone grafts are often necessary. ROS play a fundamental role in response after the implant introduction and can influence its success. This review provides insights on the mechanisms of oxidative stress generated by an implant in vivo and suitable ways for its modulation. The local delivery of active molecules, such as polyphenols, enhanced bone biomaterial integration evidencing that the management of the oxidative stress is a target for the effectiveness of an implant. Polyphenols have been widely used in medicine for cardiovascular, neurodegenerative, bone disorders and cancer, thanks to their antioxidant and anti-inflammatory properties. In addition, the perspective of new smart biomaterials and molecular medicine for the oxidative stress modulation in a programmable way, by the use of ROS responsive materials or by the targeting of selective molecular pathways involved in ROS generation, will be analysed and discussed critically
The interplay between chondrocyte spheroids and mesenchymal stem cells boosts cartilage regeneration within a 3D natural-based hydrogel
Full text linkArticular cartilage (AC) lacks the ability to self-repair and cell-based approaches, primarily based on using chondrocytes and mesenchymal stem cells (MSCs), are emerging as effective technology to restore cartilage functionality, because cells synergic functionality may support the maintenance of chondrogenic phenotype and promote extracellular matrix regeneration. This work aims to develop a more physiologically representative co-culture system to investigate the influence of MSCs on the activity of chondrocytes. A thermo-sensitive chitosan-based hydrogel, ionically crosslinked with β-glycerophosphate, is optimised to obtain sol/gel transition at physiological conditions within 5 minutes, high porosity with pores diameter <30 μm, and in vitro mechanical integrity with compressive and equilibrium Young's moduli of 37 kPa and 17 kPa, respectively. Live/dead staining showed that after 1 and 3 days in culture, the encapsulated MSCs into the hydrogels are viable and characterised by round-like morphology. Furthermore chondrocyte spheroids, seeded on top of gels that contained either MSCs or no cells, show that the encapsulated MSCs stimulate chondrocyte activity within a gel co-culture, both in terms of maintaining the coherence of chondrocyte spheroids, leading to a larger quantity of CD44 (by immunofluorescence) and a higher production of collagen and glycosaminoglycans (by histology) compared with the mono-culture
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Effetti dento-scheletrici in pazienti in crescita con malocclusione di classe II associati al trattamento con twin-block: risultati preliminari.
No full textVariations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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