In recent years, the key role of oxidative stress in pathogenesis of oral diseases has been emphasized and the use of antioxidant agents has been encouraged. Aphanizomenon flos-aquae (AFA) is a unicellular blue-green alga with antioxidant and anti-inflammatory properties. The aim of this study was the formulation and characterization of mucoadhesive thin layer films loaded with AFA, finalized to the treatment of oxidative stress (OS)-related oral diseases. First, to enhance the bioavailability of AFA constituents, the raw food grade material was appropriately treated by a high frequency homogenization able to disrupt cell walls. Thus, Eudragit^® E100-based buccal films were produced by the solvent casting method, containing 7% and 18% of AFA. The films, characterized by uniformity in thickness, weight, and drug content, showed low swelling degree, good muco-adhesiveness and controlled drug release. The mechanical tests showed elastic moduli of films of almost 5 MPa that is well-suitable for human buccal applications without discomfort, besides biaxial tests highlighted a marked material isotropy. Permeation studies through porcine mucosae demonstrated the ability of films to promote AFA penetration in the tissues, and when sublingually administered, they produced a drug flux up to six-fold higher than an AFA solution. The new formulations represent an interesting alternative for the development of cosmetics and nutraceuticals with a functional appeal containing plant extracts.

Background: The treatment of abdominal aortic aneurysm (AAA) is today commonly treated by inserting a stent-graft by the endovascular route, without resorting to open surgery. However, some clinical cases do not allow this less invasive approach, meaning that the stent-graft cannot be inserted and open surgery is used. Methods: In the study, we propose a fluid–structure interaction (FSI) analysis of an aneurysmatic aorta that could not be treated with Endovascular Aneurysm Repair (EVAR). The vessel is reconstructed through segmentation from CT scans and subsequently modeled on CAD software to create the surface and thickness of the vessel itself. Subsequently, we proceeded to carry out Computational Fluid Dynamics (CFD) and FSI simulation. We propose a computational study on a vessel geometry that is faithful to reality and customized. Results: Hemodynamic variable results of the carried out simulations indicate that low velocity and consequently very low WSS areas located in aneurysmal site are no longer found when conventional or patient-specific grafts are inserted. The wall stress distribution of aorta FEM analysis enabled the identification of the area at risk of failure, that is, in the posterior part of the aneurysm (∼${10}^7$ Pa), while FSI analysis of the patient-specific graft led to a uniform von Mises stresses distribution (∼${10}^5$ Pa), except for the junctions where peak stress occurred. Conclusion: The importance of this study is to highlight the benefits of the personalized stent/graft. As the authors expected, the study shows the numerous benefits of the customized stent/graft in terms of blood flow trend and wall stress compared to a traditional stent/graft by supporting the tendency to want to shift the target towards customized stents/grafts, also in the vascular surgery sector.

In this paper the authors introduce a nonlinear model of fractional-order hereditariness used to capture experimental data obtained on human tendons of the knee. Creep and relaxation data on fibrous tissues have been obtained and fitted with logarithmic relations that correspond to power-laws with nonlinear dependence of the coefficients. The use of a proper nonlinear transform allows one to use Boltzmann superposition in the transformed variables yielding a fractional-order model for the nonlinear material hereditariness. The fundamental relations among the nonlinear creep and relaxation functions have been established, and the results from the equivalence relations have been contrasted with measures obtained from the experimental data. Numerical experiments introducing polynomial and harmonic stress and strain histories have been reported to assess the provided equivalence relations. This article is part of the theme issue ‘Advanced materials modelling via fractional calculus: challenges and perspectives’.

A hyaluronic acid derivative able to physically crosslink in a saline aqueous medium was employed for the production of fibers with a mean diameter of 50 μm using a microfluidic technique.

In recent years, there has been a growing interest in understanding animals’ locomotion mechanisms for developing bio-inspired micro- or nano-robots capable of overcoming obstacles and navigating in confined environments. Among non-pedal crawlers, caterpillars exhibit one of the most stable and efficient gait strategies, utilizing muscle contractions and substrate grip. Although several approaches have been proposed to model their locomotion, little is known about the competition between body elasticity and adhesion, which we demonstrate playing a central role in crawling gait. Preliminarily, experimental observations and measurements were performed on Pieris brassicae larvae, gaining insights into fundamental features characterizing caterpillar locomotion and estimating key geometrical and mechanical parameters. A minimal but effective one-dimensional discrete model was thus conceived to capture all the relevant aspects of the movement. Inter-mass springs model the deformable body units, Winkler-like constraints with an adhesion threshold reproduce elastic interactions and attaching/detaching events at prolegs-substrate interface, and a triggering muscle contraction initiates the larva’s crawling cycle, generating the observed travelling wave. After demonstrating theoretically that caterpillars move obeying quasi-static laws, we proved robustness of the proposed approach by showing very good agreement between theoretical outcomes and experimental evidence, so paving the way for new optimization strategies in soft robotics.

This paper considers the case of Beck's column resting on a hereditary bed of independent springpots. The springpot possesses an intermediate rheological behaviour among linear spring and linear dashpot. It is defined by means of couple ( C _β , β ) that characterize the material of the element and is ruled by a Caputo's fractional derivative. In this paper, we investigate the critical load of the column under the action of a follower load by means of a novel complex transform that allows to use the Routh–Hurwitz theorem in the complex half-plane for the stability analysis.