161 research outputs found
Apogeotropic posterior semicircular canal benign paroxysmal positional vertigo: some clinical and therapeutic considerations
We lately reported the cases of patients complaining positional vertigo whose nystagmic pattern was that of a peripheral torsional vertical positional down beating nystagmus originating from a lithiasis of the non-ampullary arm of the posterior semicircular canal (PSC). We considered this particular pathological picture the apogeotropic variant of PSC benign paroxysmal positional vertigo (BPPV). Since the description of the pilot cases we observed more than 150 patients showing the same clinical sign and course of symptoms. In this paper we describe, in detail, both nystagmus of apogeotropic PSC BPPV (A-PSC BPPV) and symptoms reported by patients trying to give a reasonable explanation for these clinical features. Moreover we developed two specific physical therapies directed to cure A-PSC BPPV. Preliminary results of these techniques are related
Beads for Cell Immobilization: Comparison of Alternative Additive Manufacturing Techniques
The attachment or entrapment of microbial cells and enzymes are promising solutions for various industrial applications. When the traps are beads, they are dispersed in a fluidized bed in a vessel where a pump guarantees fresh liquid inflow and waste outflow without washing out the cells. Scientific papers report numerous types of cell entrapment, but most of their applications remain at the laboratory level. In the present research, rigid polymer beads were manufactured by two different additive manufacturing (AM) techniques in order to verify the economy, reusability, and stability of the traps, with a view toward a straightforward industrial application. The proposed solutions allowed for overcoming some of the drawbacks of traditional manufacturing solutions, such as the limited mechanical stability of gel traps, and they guaranteed the possibility of producing parts of constant quality with purposely designed exchange surfaces, which are unfeasible when using conventional processes. AM proved to be a viable manufacturing solution for beads with complex shapes of two different size ranges. A deep insight into the production and characteristics of beads manufactured by AM is provided. The paper provides biotechnologists with a manufacturing perspective, and the results can be directly applied to transit from the laboratory to the industrial scale
Features of Vat-Photopolymerized Masters for Microfluidic Device Manufacturing
The growing interest in advancing microfluidic devices for manipulating fluids within micrometer-scale channels has prompted a shift in manufacturing practices, moving from single-component production to medium-size batches. This transition arises due to the impracticality of lab-scale manufacturing methods in accommodating the increased demand. This experimental study focuses on the design of master benchmarks 1–5, taking into consideration critical parameters such as rib width, height, and the relative width-to-height ratio. Notably, benchmarks 4 and 5 featured ribs that were strategically connected to the inlet, outlet, and reaction chamber of the master, enhancing their utility for subsequent replica production. Vat photopolymerization was employed for the fabrication of benchmarks 1–5, while replicas of benchmarks 4 and 5 were generated through polydimethylsiloxane casting. Dimensional investigations of the ribs and channels in both the master benchmarks and replicas were conducted using an optical technique validated through readability analysis based on the Michelson global contrast index. The primary goal was to evaluate the potential applicability of vat photopolymerization technology for efficiently producing microfluidic devices through a streamlined production process. Results indicate that the combination of vat photopolymerization followed by replication is well suited for achieving a minimum rib size of 25 μm in width and an aspect ratio of 1:12 for the master benchmark
On the Biomechanical Performances of Duplex Stainless Steel Graded Scaffolds Produced by Laser Powder Bed Fusion for Tissue Engineering Applications
This experimental study aims to extend the know-how on biomechanical performances of duplex stainless steel (DSS) for tissue engineering applications to a graded lattice geometry scaffold based on the F53 DSS (UNS S32750 according to ASTM A182) produced by laser powder bed fusion (LPBF). The same dense-out graded geometry based on rhombic dodecahedral elementary unit cells investigated in previous work on 316L stainless steel (SS) was adopted here for the manufacturing of the F53 DSS scaffold (SF53). Microstructural characterization and mechanical and biological tests were carried out on the SF53 scaffold, using the in vitro behavior of the 316L stainless steel scaffold (S316L) as a control. Results show that microstructure developed as a consequence of different volume energy density (VED) values is mainly responsible for the different mechanical behaviors of SF53 and S316L, both fabricated using the same LPBF manufacturing system. Specifically, the ultimate compressive strength (σUC) and elastic moduli (E) of SF53 are three times and seven times higher than S316L, respectively. Moreover, preliminary biological tests evidenced better cell viability in SF53 than in S316L already after seven days of culture, suggesting SF53 with dense-out graded geometry as a viable alternative to 316L SS for bone tissue engineering applications
Investigation of the thermal stability of Mg/Co periodic multilayers for EUV applications
We present the results of the characterization of Mg/Co periodic multilayers
and their thermal stability for the EUV range. The annealing study is performed
up to a temperature of 400\degree C. Images obtained by scanning transmission
electron microscopy and electron energy loss spectroscopy clearly show the good
quality of the multilayer structure. The measurements of the EUV reflectivity
around 25 nm (~49 eV) indicate that the reflectivity decreases when the
annealing temperature increases above 300\degreeC. X-ray emission spectroscopy
is performed to determine the chemical state of the Mg atoms within the Mg/Co
multilayer. Nuclear magnetic resonance used to determine the chemical state of
the Co atoms and scanning electron microscopy images of cross sections of the
Mg/Co multilayers reveal changes in the morphology of the stack from an
annealing temperature of 305\degreee;C. This explains the observed reflectivity
loss.Comment: Published in Applied Physics A: Materials Science \& Processing
Published at
http://www.springerlink.com.chimie.gate.inist.fr/content/6v396j6m56771r61/ 21
page
The instrumented magnets for the OPERA experiment: construction and commissioning
The design and construction of the 990-ton gapless iron magnets for the OPERA experiment represent a major challenge from the point of view of mechanics, electric and heat engineering. Two of such magnets have been built in a deep underground hall of the Gran Sasso laboratories between 2003 and 2006 and they have been switched on for the first time in March 2006. In this paper we discuss the construction and characterization of these devices. First experience with the CNGS beam are also reported. © 2007 Elsevier B.V. All rights reserved
Prospects for the measurement of muon-neutrino disappearance at the FNAL-Booster
Neutrino physics is nowadays receiving more and more attention as a possible
source of information for the long-standing problem of new physics beyond the
Standard Model. The recent measurement of the mixing angle in the
standard mixing oscillation scenario encourages us to pursue the still missing
results on leptonic CP violation and absolute neutrino masses. However,
puzzling measurements exist that deserve an exhaustive evaluation. The NESSiE
Collaboration has been setup to undertake conclusive experiments to clarify the
muon-neutrino disappearance measurements at small , which will be able to
put severe constraints to models with more than the three-standard neutrinos,
or even to robustly measure the presence of a new kind of neutrino oscillation
for the first time. To this aim the use of the current FNAL-Booster neutrino
beam for a Short-Baseline experiment has been carefully evaluated. This
proposal refers to the use of magnetic spectrometers at two different sites,
Near and Far. Their positions have been extensively studied, together with the
possible performances of two OPERA-like spectrometers. The proposal is
constrained by availability of existing hardware and a time-schedule compatible
with the CERN project for a new more performant neutrino beam, which will
nicely extend the physics results achievable at the Booster. The possible FNAL
experiment will allow to clarify the current disappearance tension
with appearance and disappearance at the eV mass scale. Instead, a new
CERN neutrino beam would allow a further span in the parameter space together
with a refined control of systematics and, more relevant, the measurement of
the antineutrino sector, by upgrading the spectrometer with detectors currently
under R&D study.Comment: 76 pages, 52 figure
Search for anomalies in the neutrino sector with muon spectrometers and large LArTPC imaging detectors at CERN
A new experiment with an intense ~2 GeV neutrino beam at CERN SPS is proposed
in order to definitely clarify the possible existence of additional neutrino
states, as pointed out by neutrino calibration source experiments, reactor and
accelerator experiments and measure the corresponding oscillation parameters.
The experiment is based on two identical LAr-TPCs complemented by magnetized
spectrometers detecting electron and muon neutrino events at Far and Near
positions, 1600 m and 300 m from the proton target, respectively. The ICARUS
T600 detector, the largest LAr-TPC ever built with a size of about 600 ton of
imaging mass, now running in the LNGS underground laboratory, will be moved at
the CERN Far position. An additional 1/4 of the T600 detector (T150) will be
constructed and located in the Near position. Two large area spectrometers will
be placed downstream of the two LAr-TPC detectors to perform charge
identification and muon momentum measurements from sub-GeV to several GeV
energy range, greatly complementing the physics capabilities. This experiment
will offer remarkable discovery potentialities, collecting a very large number
of unbiased events both in the neutrino and antineutrino channels, largely
adequate to definitely settle the origin of the observed neutrino-related
anomalies.Comment: Contribution to the European Strategy for Particle Physics - Open
Symposium Preparatory Group, Kracow 10-12 September 201
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