1,718 research outputs found
Phantom Membrane Microfluidic Cross-Flow Filtration Device for the Direct Optical Detection of Water Pollutants
The diffusion of autonomous sensing platforms capable of a remote large-scale surveillance of environmental water basins is currently limited by the cost and complexity of standard analytical methods. In order to create a new generation of water analysis systems suitable for continuous monitoring of a large number of sites, novel technical solutions for fluid handling and detection are needed. Here we present a microfluidic device hosting a perfluorinated microporous membrane with refractive index similar to that of water, which enables the combination of filtration and label-free sensing of adsorbing substances, mainly pollutants, in environmental water samples. The cross-flow design of the microfluidic device avoids the clogging of the membrane due to particulate, whereas molecules with some hydrophobic moiety contained in the crossing flow are partially retained and their adhesion on the inner surface of the membrane yields an increase of light scattering intensity, which can be easily measured using a simple instrument based on Light Emitting Diode illumination. By cycling sample water and pure water as a reference, we demonstrate the detection of 0.5 microM of a model cationic surfactant and regeneration of the sensing surface. The optical response of the membrane sensor was characterized using a simple theoretical model that enables to quantify the concentration of target molecules from the amplitude and kinetics of the measured binding curves. The device was tested with real water samples containing large amount of environmental particles, without showing clogging of the membrane, and enabling nonspecific quantification of adsorbing substances in a few minutes.This project has received funding from the European Union’s Seventh Framework Programme (FP7) for Research, Technological Development and Demonstration through the NAPES project(grant agreement no. 604241). FBL acknowledges the Ramón y CajalProgramme (Ministerio de Economía y Competitividad), Spain. FBL personally acknowledges to Elkartek (KK-2015/00088) Grant from the Gobierno Vasco and funding support from Gobierno de España, Ministerio de Economia y Competitividad, with Grant No. BIO2016-80417-P and to Marian M. De Pancorbo for letting him to use her laboratory facilities at UPV/EHU. PSA was generously provided byAdhesive Research, Ireland. We thank Aurora Giavazzi for helping in the collection of river water samples
Analytical validation and clinical application of rapid serological tests for sars-cov-2 suitable for large-scale screening
Recently, large-scale screening for COVID-19 has presented a major challenge, limiting timely countermeasures. Therefore, the application of suitable rapid serological tests could provide useful information, however, little evidence regarding their robustness is currently available. In this work, we evaluated and compared the analytical performance of a rapid lateral-flow test (LFA) and a fast semiquantitative fluorescent immunoassay (FIA) for anti-nucleocapsid (anti-NC) antibodies, with the reverse transcriptase real-time PCR assay as the reference. In 222 patients, LFA showed poor sensitivity (55.9%) within two weeks from PCR, while later testing was more reliable (sensitivity of 85.7% and specificity of 93.1%). Moreover, in a subset of 100 patients, FIA showed high sensitivity (89.1%) and specificity (94.1%) after two weeks from PCR. The coupled application for the screening of 183 patients showed satisfactory concordance (K = 0.858). In conclusion, rapid serological tests were largely not useful for early diagnosis, but they showed good performance in later stages of infection. These could be useful for back-tracing and/or to identify potentially immune subjects
Magnesium sulphate in the Emergency Department: an old, new friend
With our study, we searched the medical literature to find magnesium (Mg) correlation with Emergency situations or its use in Emergency Medicine. Our aim is to fill the gap that we find in our daily routine between Mg studies on its role in Emergency and the real conception that doctors have of it in medical practice. We searched the literature for terms as magnesium or magnesium sulphate, magnesium in emergency, eclampsia, arrhythmias, acute asthma exacerbation, magnesium, and pediatric population. After a thorough research, we divided our discoveries into chapters to sort out a large amount often discordant articles
Search for massive rare particles with MACRO
Massive rare particles have been searched for in the penetrating cosmic
radiation using the MACRO apparatus at the Gran Sasso National Laboratories.
Liquid scintillators, streamer tubes and nuclear track detectors have been used
to search for magnetic monopoles (MMs).
Based on no observation of such signals, stringent flux limits are
established for MMs as slow as a few 10^(-5)c. The methods based on the
scintillator and on the nuclear track subdetectors were also applied to search
for nuclearites. Preliminary results of the searches for charged Q-balls are
also presented.Comment: 20 pages, 9 EPS figures included with epsfi
Measurement of the residual energy of muons in the Gran Sasso underground Laboratories
The MACRO detector was located in the Hall B of the Gran Sasso underground
Laboratories under an average rock overburden of 3700 hg/cm^2. A transition
radiation detector composed of three identical modules, covering a total
horizontal area of 36 m^2, was installed inside the empty upper part of the
detector in order to measure the residual energy of muons. This paper presents
the measurement of the residual energy of single and double muons crossing the
apparatus. Our data show that double muons are more energetic than single ones.
This measurement is performed over a standard rock depth range from 3000 to
6500 hg/cm^2.Comment: 28 pages, 9 figure
The primary cosmic ray composition between 10**15 and 10**16 eV from Extensive Air Showers electromagnetic and TeV muon data
The cosmic ray primary composition in the energy range between 10**15 and
10**16 eV, i.e., around the "knee" of the primary spectrum, has been studied
through the combined measurements of the EAS-TOP air shower array (2005 m
a.s.l., 10**5 m**2 collecting area) and the MACRO underground detector (963 m
a.s.l., 3100 m w.e. of minimum rock overburden, 920 m**2 effective area) at the
National Gran Sasso Laboratories. The used observables are the air shower size
(Ne) measured by EAS-TOP and the muon number (Nmu) recorded by MACRO. The two
detectors are separated on average by 1200 m of rock, and located at a
respective zenith angle of about 30 degrees. The energy threshold at the
surface for muons reaching the MACRO depth is approximately 1.3 TeV. Such muons
are produced in the early stages of the shower development and in a kinematic
region quite different from the one relevant for the usual Nmu-Ne studies. The
measurement leads to a primary composition becoming heavier at the knee of the
primary spectrum, the knee itself resulting from the steepening of the spectrum
of a primary light component (p, He). The result confirms the ones reported
from the observation of the low energy muons at the surface (typically in the
GeV energy range), showing that the conclusions do not depend on the production
region kinematics. Thus, the hadronic interaction model used (CORSIKA/QGSJET)
provides consistent composition results from data related to secondaries
produced in a rapidity region exceeding the central one. Such an evolution of
the composition in the knee region supports the "standard" galactic
acceleration/propagation models that imply rigidity dependent breaks of the
different components, and therefore breaks occurring at lower energies in the
spectra of the light nuclei.Comment: Submitted to Astroparticle Physic
Search for Nucleon Decays induced by GUT Magnetic Monopoles with the MACRO Experiment
The interaction of a Grand Unification Magnetic Monopole with a nucleon can
lead to a barion-number violating process in which the nucleon decays into a
lepton and one or more mesons (catalysis of nucleon decay). In this paper we
report an experimental study of the effects of a catalysis process in the MACRO
detector. Using a dedicated analysis we obtain new magnetic monopole (MM) flux
upper limits at the level of for
, based on the search for
catalysis events in the MACRO data. We also analyze the dependence of the MM
flux limit on the catalysis cross section.Comment: 12 pages, Latex, 10 figures and 2 Table
Low energy atmospheric muon neutrinos in MACRO
We present the measurement of two event samples induced by atmospheric
of average energy . In the first sample,
the neutrino interacts inside the MACRO detector producing an upward-going muon
leaving the apparatus. The ratio of the number of observed to expected events
is with an angular
distribution similar to that expected from the Bartol atmospheric neutrino
flux. The second is a mixed sample of internally produced downward-going muons
and externally produced upward-going muons stopping inside the detector. These
two subsamples are selected by topological criteria; the lack of timing
information makes it impossible to distinguish stopping from downgoing muons.
The ratio of the number of observed to expected events is . Using the ratio of the two subsamples (for
which most theoretical uncertainties cancel) we can test the pathlength
dependence of the oscillation hypothesis. The probability of agreement with the
no-oscillation hypothesis is 5% .
The deviations of our observations from the expectations has a preferred
interpretation in terms of oscillations with maximal mixing and
. These parameters are in agreement
with our results from upward throughgoing muons, induced by of much
higher energies.Comment: 7 pages, 6 figures. Submitted to Phys. Lett.
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