SEM characterization and ageing analysis on two generation of invisible aligners

Abstract Background: The purpose of the in vitro study is to investigate and compare the morphological features and the chemical stability in weight of two different polyurethane-based blends, Smart Track (LD30) and Exceed30 (EX30), used for orthodontic aligners manufacture before and after the oral usage. Methods: Twenty orthodontic aligners were randomly selected: 10 LD30 and 10 EX30, each group was divided in two subgroups, never used and intra-orally aged. By the employment of a Stereomicroscope, a section of 5 × 5 mm was cut from the buccal surface of the incisal region of each aligner. All samples were subjected to Scanning Electron Microscopy and Ageing tests in different solutions to simulate the hostility of the oral environment. The statistical method used was t-test. Results: At SEM images, LD30 appears more homogeneous in texture respect to EX30. However, after clinical usage, both materials show significant structural alterations: findings have been supported by higher magnifications at SEM, by which it is clearly to observe many superficial cracks cross through the polymer structures of LD30U, absent in never used samples. LD30U surface becomes also smoother due to the disappearance of most of the conglomerates, but at the same time also rougher while EX30U shows a greater irregularity and porosity in which large and deep cracks are also highlighted. Although these changes occur persistently, in the aging tests no significant weight loss from both materials has been found, confirming the initial hypothesis of a good chemical stability and safety of both polyurethane mixtures even in conditions of severe hostility. Conclusion: LD30 is the expression of the technological evolution of EX30, this is made evident above all by its morphological architecture, more homogeneous and defined but also by the chemical stability that can be appreciated even in evident critic situations

The rapid spread of SARS-COV-2 Omicron variant in Italy reflected early through wastewater surveillance

The SARS-CoV-2 Omicron variant emerged in South Africa in November 2021, and has later been identified worldwide, raising serious concerns. A real-time RT-PCR assay was designed for the rapid screening of the Omicron variant, targeting characteristic mutations of the spike gene. The assay was used to test 737 sewage samples collected throughout Italy (19/21 Regions) between 11 November and 25 December 2021, with the aim of assessing the spread of the Omicron variant in the country. Positive samples were also tested with a real-time RT-PCR developed by the European Commission, Joint Research Centre (JRC), and through nested RT-PCR followed by Sanger sequencing. Overall, 115 samples tested positive for Omicron SARS-CoV-2 variant. The first occurrence was detected on 7 December, in Veneto, North Italy. Later on, the variant spread extremely fast in three weeks, with prevalence of positive wastewater samples rising from 1.0% (1/104 samples) in the week 5-11 December, to 17.5% (25/143 samples) in the week 12-18, to 65.9% (89/135 samples) in the week 19-25, in line with the increase in cases of infection with the Omicron variant observed during December in Italy. Similarly, the number of Regions/Autonomous Provinces in which the variant was detected increased from one in the first week, to 11 in the second, and to 17 in the last one. The presence of the Omicron variant was confirmed by the JRC real-time RT-PCR in 79.1% (91/115) of the positive samples, and by Sanger sequencing in 66% (64/97) of PCR amplicons. In conclusion, we designed an RT-qPCR assay capable to detect the Omicron variant, which can be successfully used for the purpose of wastewater-based epidemiology. We also described the history of the introduction and diffusion of the Omicron variant in the Italian population and territory, confirming the effectiveness of sewage monitoring as a powerful surveillance tool

"Smart" lipid microbubbles for targeting and drug delivery

“Smart” lipid microbubbles for targeting and drug delivery Gaio Paradossi, Barbara Cerroni, Letizia Oddo Dipartimento di Scienze e Tecnologie Chimiche, Università di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome, Italy. Lipid microbubbles are known as ultrasound contrast agents (UCAs). They consist of hydrophobic gas, tipically a perfluorocarbon or sulfur hexafluoride, encapsulated by a shell of surfactant molecules assembled as monolayer. To address UCAs on tumor endothelial cells, we decorated their surface with the cyclic pentapeptide, cyclo(Arg-Gly-Asp-D-Phe-Cys) ), containing the sequence RGD, or its analog cyclo(Arg-Ala-Asp-D-Phe-Cys) with a RAD sequence as positive control. RGD sequence is recognized by integrins, the transmembrane proteins overexpressed by tumor endothelial cells or human umbilical vein endothelial cells (HUVEC). In this contribution we tested the bioadhesion of RGD decorated UCAs under controlled and realistic flow conditions such as shear rate, channel diameter, temperature on HUVEC and, as positive control, on fibrablasts NIH3T3 cell lines. Sonoporation, the reversible opening of cell membrane upon ultrasound irradiation, can be a method to favor the internalization of drugs. However, a careful optimization of the process is needed to warrant cells viability. The presence of the microbubbles affects the efficiency of the method. This research has been supported by the FP7 Eu project “TheraGlio”. “Smart” lipid microbubbles for targeting and drug delivery Gaio Paradossi, Barbara Cerroni, Letizia Oddo Dipartimento di Scienze e Tecnologie Chimiche, Università di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome, Italy. Lipid microbubbles are known as ultrasound contrast agents (UCAs). They consist of hydrophobic gas, tipically a perfluorocarbon or sulfur hexafluoride, encapsulated by a shell of surfactant molecules assembled as monolayer. To address UCAs on tumor endothelial cells, we decorated their surface with the cyclic pentapeptide, cyclo(Arg-Gly-Asp-D-Phe-Cys) ), containing the sequence RGD, or its analog cyclo(Arg-Ala-Asp-D-Phe-Cys) with a RAD sequence as positive control. RGD sequence is recognized by integrins, the transmembrane proteins overexpressed by tumor endothelial cells or human umbilical vein endothelial cells (HUVEC). In this contribution we tested the bioadhesion of RGD decorated UCAs under controlled and realistic flow conditions such as shear rate, channel diameter, temperature on HUVEC and, as positive control, on fibrablasts NIH3T3 cell lines. Sonoporation, the reversible opening of cell membrane upon ultrasound irradiation, can be a method to favor the internalization of drugs. However, a careful optimization of the process is needed to warrant cells viability. The presence of the microbubbles affects the efficiency of the method. This research has been supported by the FP7 Eu project “TheraGlio”

Adding Chemical Cross-Links to a Physical Hydrogel

molecule

Cross-layer resource orchestration for cloud service delivery: A seamless SDN approach

Abstract One of the main challenges of cloud-based service provisioning is to deploy a coordinated control of both application- and network-layer resources in order to provide adaptive service data delivery and adequate user service experiences. In this work we propose a signaling framework architecture for cross-layer resource orchestration, where service awareness provided by session control is effectively combined with the flexibility of software-defined network control. Following a hands-on approach, the proposed solution takes advantage of existing and commonly deployed technologies aiming at an incremental deployment of the software-defined control mechanisms for the purpose of cross-functional service orchestration. The signaling framework is presented and validated through experimental activities carried out on a test-bed reproducing a realistic cloud-based service scenario. Results are compared against an analytical model that allows to investigate and quantify the sensitivity of the cloud-based service performance to the most relevant system parameters. The study demonstrates that a critical role is played by the limitations of the response time of real devices such as commercial routers, and highlights how orchestration functions can mitigate the effect of such limitations while addressing scalability of the overall system

Biomimetic giant vesicles electroformation: biophysical evidences

Giant Unilamellar Vesicles (GUV) are liposomes of 10-100 μm of diameter formed by a single phospholipid bilayer encompassing an aqueous core. Their cell-like size motivates the wide use of GUV as model membrane system, with the advantage to be visible under light microscope. The most commonly used method of GUV preparation is the so called “electroswelling” of lipids under Alternating Current electric field which leads to a homogeneous population of spherical vesicles characterized by a narrow size distribution. Despite their great relevance as biomimetic system, the underlying mechanism of GUV formation is still poorly understood and an univocal model explaining the vesicles formation is still lacking. In this work, by using phase contrast microscopy we have performed a real time study on the kinetic of GUV growth. At the same time, we have characterized the structural and topological properties of electroformed vesicles through fluorescence and confocal microscopy, with the final aim to define a simple and intuitive model which connects the vesicles features with the electric field parameters, namely frequency, voltage and waveform

In vitro analysis of the trajectories of adhesive microbubbles approaching endothelial cells

Adhesion is a key process when ultrasound contrast agents, i.e. microbubbles, approach pathological tissues. A way to accomplish tumour targeting is to tether surface engineered microbubbles to endothelial cells of the up-regulated vascularization of cancer tissues. This can be achieved by coupling the microbubbles surface with the Arginine-Glycine-Aspartate, RGD, sequence. Such molecule interacts with the integrin receptors placed on the endothelial cells. Stability and trajectories of RGD modified lipid shelled MBs have been analysed in vitro using microchannels coated with human umbilical vein endothelial cells, HUVEC. In the microchannels realistic conditions, close to the physiological ones, were reproduced replicating shear rate, roughness comparable to the endothelium and channel size mimicking the postcapillary venules. In these conditions, the analysis of the trajectories close to the walls highlights a substantial difference between the modified MBs and the plain ones. Moreover, MBs adhesion has dynamic features recalling the motion of neutrophils engaged near the substrate such as rolling, translations and transient detachments. These findings are useful for the optimization of in vivo imaging and targeting functions