604 research outputs found
Long-term physical evolution of an elastomeric ultrasound contrast microbubble
Hypothesis: One of the main assets of crosslinked polymer-shelled microbubbles (MBs) as ultrasound-active theranostic agents is the robustness of the shells, combined with the chemical versatility in modifying the surface with ligands and/or drugs. Despite the long shelf-life, subtle modifications occur in the MB shells involving shifts in acoustic, mechanical and structural properties. Experiments: We carried out a long-term morphological and acoustic evolution analysis on elastomeric polyvinyl-alcohol (PVA)-shelled MBs, a novel platform accomplishing good acoustic and surface performances in one agent. Confocal laser scanning microscopy, acoustic spectroscopy and AFM nanomechanics were integrated to understand the mechanism of PVA MBs ageing. The changes in the MB acoustic properties were framed in terms of shell thickness and viscoelasticity using a linearised oscillation theory, and compared to MB morphology and to nanomechanical analysis. Findings: We enlightened a novel, intriguing ageing time evolution of the PVA MBs with double behaviour with respect to a crossover time of ∼50 days. Before, significant changes occur in MB stiffness and shell thickness, mainly due to a massive release of entangled PVA chains. Then, the MB resonance frequency increases together with shell thickening and softening. Our benchmark study is of general interest for emerging viscoelastomeric bubbles towards personalised medicine
Differential effects on membrane permeability and viability of human keratinocyte cells undergoing very low intensity megasonic fields
Among different therapeutic applications of Ultrasound (US), transient membrane sonoporation (SP) - a temporary, non-lethal porosity, mechanically induced in cell membranes through US exposure - represents a compelling opportunity towards an efficient and safe drug delivery. Nevertheless, progresses in this field have been limited by an insufficient understanding of the potential cytotoxic effects of US related to the failure of the cellular repair and to the possible activation of inflammatory pathway. In this framework we studied the in vitro effects of very low-intensity US on a human keratinocyte cell line, which represents an ideal model system of skin protective barrier cells which are the first to be involved during medical US treatments. Bioeffects linked to US application at 1 MHz varying the exposure parameters were investigated by fluorescence microscopy and fluorescence activated cell sorting. Our results indicate that keratinocytes undergoing low US doses can uptake drug model molecules with size and efficiency which depend on exposure parameters. According to sub-cavitation SP models, we have identified the range of doses triggering transient membrane SP, actually with negligible biological damage. By increasing US doses we observed a reduced cells viability and an inflammatory gene overexpression enlightening novel healthy relevant strategies
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Accessing and assessing lunar resources with PROSPECT
PROSPECT is a package in development by ESA to assess the in-situ resource potential of lunar regolith. PROSPECT will: obtain sub-surface regolith samples, extract volatiles, identify chemical species, quantify abundances, and characterize isotopes
An experimental study on latency-aware and self-adaptive service chaining orchestration in distributed NFV and SDN infrastructures
Network Function Virtualization (NFV) and Software Defined Networking (SDN) changed radically the way 5G networks will be deployed and services will be delivered to vertical applications (i.e., through dynamic chaining of virtualized functions deployed in distributed clouds to best address latency requirements). In this work, we present a service chaining orchestration system, namely LASH-5G, running on top of an experimental set-up that reproduces a typical 5G network deployment with virtualized functions in geographically distributed edge clouds. LASH-5G is built upon a joint integration effort among different orchestration solutions and cloud deployments and aims at providing latency-aware, adaptive and reliable service chaining orchestration across clouds and network resource domains interconnected through SDN. In this paper, we provide details on how this orchestration system has been deployed and it is operated on top of the experimentation infrastructure provided within the Fed4FIRE+ facility and we present performance results assessing the effectiveness of the proposed orchestration approach
Assessment of Psychometric Characteristics of Parkinson’s Disease Sleep Scale 2 and Analysis of a Cut-Off Score for Detecting Insomnia in Italian Patients with Parkinson’s Disease: A Validation Study
introduction: sleep disorders are frequent non-motor symptoms affecting patients with parkinson's disease (PD). Insomnia represents the most common sleep disorder. parkinson's disease Sleep Scale 2 (PDSS-2) is a specific tool to investigate sleep problems in PD. the general sleep disturbances scale (GSDS) was a general scale validated for the Italian population. our goal was to assess the psychometric characteristics of PDSS-2 and the GSDS in this population, calculating a cut-off score for insomnia symptoms by using subitems of PDSS-2. methods: patients admitted at the PD unit of the hospital of rome tor vergata outpatient clinic and those afferent to PD associations were asked to complete PDSS-2 and GSDS to be correlated to identify a cut-off for insomnia symptoms. Items 1,2,3,8,13 of PDSS-2 were used to detect insomnia. an ROC curve to assess a cut-off score for insomnia was determined. a cross-cultural analysis of PD population characteristics was performed. results: In total, 350 PD patients were recruited. cronbach's alpha was high for the total score (0.828 for PDSS-2 and 0.832 for GSDS). a cross-cultural analysis did not show any significant p-value. the ROC curve yielded an AUC of 0.79 (CI: 0.75-0.84). the cut-off value for insomnia disorder based on items 1,2,3,8,13 of PDSS-2 was >10, demonstrating a sensitivity of 76% and a specificity of 69% in determining the presence of subjective insomnia symptoms in PD. discussion: PDSS-2 is demonstrated to be a valid, specific tool to address sleep disturbances in PD patients. a cut-off score of 10 for items 1,2,3,8,13 was identified for detecting insomnia symptoms in PD patients
Deep-underground search for the decay of 180m-Ta with an ultra-low-background HPGe detector
Ta is the longest-lived metastable state presently known. Its decay
has not been observed yet. In this work, we report a new result on the decay of
Ta obtained with a -g tantalum sample measured for d
with an ultra-low background HPGe detector in the STELLA laboratory of the
Laboratori Nazionali del Gran Sasso, in Italy. Before the measurement, the
sample has been stored deep-underground for ten years, resulting in subdominant
background contributions from cosmogenically activated Ta. We observe
no signal in the regions of interest and set half-life limits on the process
for the two channels EC and : yr and yr (% C. I.),
respectively. We also set the limit on the de-excitation / IC channel:
yr (% C. I.). These are, as of
now, the most stringent bounds on the decay of Ta worldwide.Comment: 8 pages, 7 figures, 4 table
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