25 research outputs found
Distributed Bragg reflectors for the colorimetric detection of bacterial contaminants and pollutants for food quality control
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The physics of plasma membrane photostimulation
Cell membrane perturbation is a common way to stimulate cells by using external actuators. Recently, nanotechnology has added a number of new strategies for doing this, enlarging the scope and the range of mechanisms involved. Here, we describe a number of possible perturbation actions that are driven by light, and we try to capture the underlying phenomena. The discussion is based on the simple equivalent circuit model for the cell membrane
Survey of transfemoral amputee experience and priorities for the user-centered design of powered robotic transfemoral prostheses
BACKGROUND: Transfemoral amputees experience a complex host of physical, psychological, and social challenges, compounded by the functional limitations of current transfemoral prostheses. However, the specific relationships between human factors and prosthesis design and performance characteristics have not yet been adequately investigated. The present study aims to address this knowledge gap. METHODS: A comprehensive single-cohort survey of 114 unilateral transfemoral amputees addressed a broad range of demographic and clinical characteristics, functional autonomy, satisfaction and attitudes towards their current prostheses, and design priorities for an ideal transfemoral prosthesis, including the possibility of active assistance from a robotic knee unit. The survey was custom-developed based on several standard questionnaires used to assess motor abilities and autonomy in activities of daily living, prosthesis satisfaction, and quality of life in lower-limb amputees. Survey data were analyzed to compare the experience (including autonomy and satisfaction) and design priorities of users of transfemoral prostheses with versus without microprocessor-controlled knee units (MPKs and NMPKs, respectively), with a subsequent analyses of cross-category correlation, principal component analysis (PCA), cost-sensitivity segmentation, and unsupervised K-means clustering applied within the most cost-sensitive participants, to identify functional groupings of users with respect to their design priorities. RESULTS: The cohort featured predominantly younger (< 50 years) traumatic male amputees with respect to the general transfemoral amputee population, with pronounced differences in age distribution and amputation etiology (traumatic vs. non-traumatic) between MPK and NMPK groups. These differences were further reflected in user experience, with MPK users reporting significantly greater overall functional autonomy, satisfaction, and sense of prosthesis ownership than those with NMPKs, in conjunction with a decreased incidence of instability and falls. Across all participants, the leading functional priorities for an ideal transfemoral prosthesis were overall stability, adaptability to variable walking velocity, and lifestyle-related functionality, while the highest-prioritized general characteristics were reliability, comfort, and weight, with highly variable prioritization of cost according to reimbursement status. PCA and user clustering analyses revealed the possibility for functionally relevant groupings of prosthesis features and users, based on their differential prioritization of these features—with implications towards prosthesis design tradeoffs. CONCLUSIONS: This study’s findings support the understanding that when appropriately prescribed according to patient characteristics and needs in the context of a proactive rehabilitation program, advanced transfemoral prostheses promote patient mobility, autonomy, and overall health. Survey data indicate overall stability, modularity, and versatility as key design priorities for the continued development of transfemoral prosthesis technology. Finally, observed associations between prosthesis type, user experience, and attitudes concerning prosthesis ownership suggest both that prosthesis characteristics influence device acceptance and functional outcomes, and that psychosocial factors should be specifically and proactively addressed during the rehabilitation process. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12984-021-00944-x
Traceable atomic force microscopy of high-quality solvent-free crystals of [6,6]-phenyl-C 61
Optimisation Study of the Fabry-PĂ©rot Optical Cavity for the MARIX/BRIXS Compton X-Ray Source
Manufacturing of advanced bent crystals for Laue Optics for Gamma ObservationS (LOGOS)
X- and c-ray detection is currently a hot topic for a wide scientific community, spanning from astrophysics to nuclear medicine. However, lack of optics capable of focusing photons of energies in the energy range 0.1–1 MeV leaves the photon detection to a direct-view approach, resulting in a limited efficiency and resolution. The main scope of the INFN-LOGOS project is the development of technologies that enable manufacturing highly performing optical elements to be employed in the realization of hard X-ray lenses. Such lenses, typically named Laue lenses, consist of an ensemble of crystals disposed in concentric rings in order to diffract the incident radiation towards the focus of the lens, where a detector is placed. In particular, the INFN-LOGOS project aims at the realization of intrinsically bent silicon and germanium crystals exploiting the quasi-mosaic effect for focusing hard X-rays. Crystal manufacturing relies on a proper revisitation of techniques typically employed in silicon micromachining, such as thin film deposition and patterning or ion implantation
Reshaping Hybrid Perovskites Emission with Flexible Polymer Microcavities
Thanks to versatile optoelectronic properties solution processable perovskites have attracted increasing interest as active materials in photovoltaic and light emitting devices. However, the deposition of perovskite thin films necessitates wide range solvents that are incompatible with many other solution-processable media, including polymers that are usually dissolved by the perovskite solvents. In this work, we demonstrate that hybrid perovskite thin films can be coupled with all polymer planar photonic crystals with different approaches to achieve emission intensity enhancement and reshaping using different approaches. The possibility to control and modify the emission spectrum of a solution processable perovskite via a simple spun-cast polymer structure is indeed of great interest in optoelectronic applications requiring high color purity or emission directionality. Furthermore, thanks to the ease of fabrication and scalability of solution-processed photonic crystals, this approach could enable industrial scale production of low-cost, large area, lightweight and flexible polymer-perovskite lighting devices, which may be tuned without resorting to compositional engineering
A Characterization System for the Monitoring of ELI-NP Gamma Beam
The ELI-NP (Extreme Light Infrastructure-Nuclear Physics) facility, currently under
construction near Bucharest (Romania), is the pillar of the project ELI dedicated to the generation of
high-brilliance gamma beams and high-power laser pulses that will be used for frontier research in
nuclear physics. To develop an experimental program at the frontiers of the present-day knowledge,
two pieces of equipment will be deployed at ELI-NP: a high power laser system consisting of two
10 PW lasers and a high brilliance gamma beam system. The ELI-NP Gamma beam system will
deliver an intense gamma beam with unprecedented specifications in terms of photon flux, brilliance
and energy bandwidth in an energy range from 0.2 to 20 MeV. Such a gamma beam requires special
devices and techniques to measure and monitor the beam parameters during the commissioning and
the operational phase. To accomplish this task, the Gamma Beam Characterization System, equipped
with four elements, was developed: a Compton spectrometer (CSPEC), to measure and monitor the
photon energy spectrum; a nuclear resonant scattering system (NRSS), for absolute beam energy
calibration and inter-calibration of the other detectors; a beam profile imager (GPI) to be used for
alignment and diagnostics purposes; and finally a sampling calorimeter (GCAL), for a fast combined
measurement of the beam average energy and intensity. The combination of the measurements
performed by GCAL and CSPEC allows fully characterizing the gamma beam energy distribution
and intensity with a precision at the level of few per mill, enough to demonstrate the fulfillment
of the required parameters. This article presents an overview of the gamma beam characterization
system with focus on these two detectors, which were designed, assembled and are currently under
test at INFN-Firenze. The layout and the working principle of the four devices is described, as well
as some of the main results of detector test