71 research outputs found
Development of functionally graded constructs via 3D microfluidic bioprinting for the regeneration of skeletal defects
No full textSkeletal tissue engineering aims to prevail limitations of traditional treatments for bone defects by developing biomaterials that mimic the complex hierarchical architecture of natural bone. However, current biofabrication techniques face challenges in achieving both structural precision and biological compatibility. A major limitation is the lack of scalable methods to produce functionally graded materials (FGM) that support cell proliferation and differentiation while maintaining mechanical stability. This thesis proposes the development of a 3D microfluidic bioprinting platform using oil-in-water (O/W) and water-in-water emulsions (W/W) to fabricate porous scaffolds with controlled gradient structures. Crucially, integrating low-intensity pulsed ultrasound (LIPUS) stimulation and microbubbles (MBs) into the 3D bioprinting process for the first time, a functional response for cell growth and enhanced the osteogenic differentiation of skeletal stem cells (SSCs) was elicited. The results demonstrate that the 3D bioprinted constructs can actively promote effective bone tissue regeneration, addressing key limitations of current regenerative strategies, aforementioned. This thesis provides a novel, scalable solution for the creation of biocompatible and functional skeletal tissue constructs, with significant implications for clinical applications in bone repair
La strategia delle indagini archeologiche e il cantiere di restauro: occasioni e criticità
No full text
Harnessing microfluidic bioprinting to fabricate gradient-like porous 3D constructs via emulsion ink deposition
No full textThe exceptional properties of natural structures with density gradients (e.g. bone, sponges,bamboo) have stimulated the interest in reproducing such complex architectures harnessingbiopolymer functionality. However, the possibility to generate a hierarchical structurecomprising multiple density gradient has not yet demonstrated, mainly due to the lack oftechnological advancements in engineering of new emulsion materials and rapid fabricationplatforms.In the current work, we reported the 3D printing of porosity-controlled dextran methacrylate(DexMA) oil-in-water (o-w) emulsions using a microfluidic circuit and a fluid-gel supportbath. The fabrication of density gradient scaffolds within a supporting gel overcomes theproblems associated with low-viscosity bioink extrusion in 3D printing, supporting densitygradient structures that would be otherwise impossible to print in-air. The density gradientwas engineered using a flow-focusing printhead. The characterisation of the emulsionsdemonstrated how the regulation of the continuous and dispersed phases by using microfluidicpumps allowed the controlled and automated tuning of the material final porosity. Therefore,we proved that a higher droplet diameter is obtained by increasing the flow rate of the oil phasewith a direct and significant proportionality between the diameter and the volume fraction ofthe dispersed phase (p<0.0001). The rheological characterisation of the emulsions revealeda decrease in viscosity as the applied shear rate increased. The continuous phase of DexMAand Pluronic F-68 exhibited a Newtonian fluid-like trend, while the emulsions presented anincreasingly pseudoplastic behaviour with expanding dispersed phase volume fraction.To show the effectiveness of the developed methodology, we realised complex geometriesconsisting of porous biopolymer fibres, as well as porous scaffolds with axial (two, four andalternate) and radial density obtain differential regions within a single construct. The inclusion ofphoto-radical initiators in the outer phase of the inks enabled the crosslinking of the structure,following printing, directly into the supporting fluid-gel medium.The 3D printed porous scaffolds exhibited high-end mechanical properties and elastic responseto applied strains. Furthermore, morphological characterisation allowed the observation ofthe hierarchical internal porous architecture of the scaffolds using X-ray computed micro-tomography (μCT), scanning electron (SEM) and laser scanning confocal microscopy (LSCM),confirming the ability of the novel bioprinting platform to deposit high-resolution densitygradient constructs in 3D.Moreover, we demonstrated the possibility to print highly complex density gradient structures (e.g. free-standing stairs, inverted pyramids, hollow structures) with extremely low viscosityusing an agarose fluid-gel. Furthermore, we investigated the printing of a combination ofmaterials (DexMA and GelMA; DexMA and nHA) by a multi-inlet flow-focusing printhead,resulting in density gradient structures with hierarchical mechanical properties and swellingability.Altogether, this work outlines the potential of combining microfluidics and rapid prototypingtechniques with the use of a suspending medium, providing a viable alternative for optimally 3Dprinting of biphasic systems with low viscosities and controlled densities
Surveying the rural village of Al-Jāyyah (Ma’an Governorate, Jordan): archaeological methodologies and first results
No full textSurveying the rural village of Al-Jāyyah (Ma’an Governorate, Jordan): archaeological methodologies and first results. A contribution to the knowledge of the Shawbak territorial settlement in the longue durée
This paper presents some preliminary results about systematic Light Archaeology surveys (integrating Building and Landscape Archaeology) that the author is leading in the village of Al-Jāyyah, SE ofthe Shawbak castle, within the archaeological investigations on the landscape surrounding the fortress managed by the Italian archaeological Mission‘Medieval Petra,’ University of Florence. The aim of the surveys is to investigate the historical connection between the castle and the village, suggested by some Medieval written sources. The research’s preliminary outcomes are confirming that even if the present appearance of the village is modern, it preserves significant Medieval material evidences plausibly linked to the Crusader suburb and the Islamic madīnah of Shawbak
Emotional Dysregulation and Adaptive Functioning in Preschoolers With Autism Spectrum Disorder or Other Neurodevelopmental Disorders
No full textAimEmotional dysregulation (ED), defined by deficits in the ability to monitor and modulate the valence, intensity, and expression of emotions, is typically expressed with irritability, tantrums, mood fluctuations, and self-harm in young children with autism spectrum disorder (ASD). Although ED does not represent a diagnostic feature of ASD, its manifestations are an important contributor to functional impairment and clinical referral. This study aims to examine the relationship between ED and adaptive functioning in preschoolers clinically referred for ASD or other neurodevelopmental disorders. MethodsA sample of 100 children (74% males, mean age 39.4 +/- 12.3 months), consecutively referred to a university clinic for neurodevelopmental disorders, received clinical assessments of psychopathology with the CBCL and the Autism Diagnostic Interview-Revised, of ED- with the CBCL-Attention, Anxious/Depressed, and Aggression index (CBCL-AAA), of autism symptom severity with the ADOS-2 Calibrated Severity Score (ADOS-CSS), and of global developmental/cognitive delay (GDD) with the WPPSI-IV or other age-appropriate standardized scales. Adaptive functioning was measured with the ABAS-II. Sixty-five children met DSM-5 criteria for ASD. Multivariate regression models were applied to evaluate the relative contribution of ED, ASD severity and GDD to the ABAS-II general (GAC), conceptual (CAD), social (SAD), and practical (PAD) adaptive functioning domains. ResultsOverall (n = 100), lower adaptive functioning was associated with higher CBCL-AAA (p = 0.003), higher ADOS-CSS (p < 0.001), and presence of GDD (p = 0.023). In the ASD group (n = 65), worse CAD was predicted by GDD (p = 0.016), and worse SAD and PAD by higher ADOS-CSS (p = 0.032) and ED (p = 0.002). No sex differences were detected in the study variables. ConclusionTogether with the severity of global developmental delay and of autism symptoms, ED is a significant contributor to impairment in adaptive functioning among young children with a neurodevelopmental disorder and, in particular, with ASD. ED could represent a specific target for early interventions aimed at enhancing adaptive functioning in early childhood
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