729 research outputs found
Non-equilibrium readiness and accuracy of Gaussian Quantum Thermometers
The dimensionality of a thermometer is key in the design of quantum
thermometry schemes. In general, the phenomenology that is typical of
finite-dimensional quantum thermometry does not apply to infinite dimensional
ones. We analyse the dynamical and metrological features of non-equilibrium
Gaussian Quantum Thermometers: on one hand, we highlight how quantum
entanglement can enhance the readiness of composite Gaussian thermometers; on
the other hand, we show that non-equilibrium conditions do not guarantee the
best sensitivities in temperature estimation, thus suggesting the reassessment
of the working principles of quantum thermometry
Monitoring dispersive samples with single photons: the role of frequency correlations
The physics that governs quantum monitoring may involve other degrees of
freedom than the ones initialised and controlled for probing. In this context
we address the simultaneous estimation of phase and dephasing characterizing a
dispersive medium, and we explore the role of frequency correlations within a
photon pair generated via parametric down-conversion, when used as a probe for
the medium. We derive the ultimate quantum limits on the estimation of the two
parameters, by calculating the corresponding quantum Cram\'er-Rao bound; we
then consider a feasible estimation scheme, based on the measurement of Stokes
operators, and address its absolute performances in terms of the correlation
parameters, and, more fundamentally, of the role played by correlations in the
simultaneous achievability of the quantum Cram\'er-Rao bounds for each of the
two parameters.Comment: to appear in Quantum Measurements and Quantum Metrolog
Implementation of eco-sustainable biocomposite materials reinforced by optimized agave fibers
Although several works have recently been published in literature about biocomposites, i.e. about composites with polymeric matrix reinforced by natural fibers, only a few articles have been devoted to the implementation of high performance biocomposites for structural and semi-structural applications. The present study aims to give a contribution by considering biocomposites obtained by using an eco-friendly partially bio-based epoxy (green epoxy) and sisal (agave sisalana fibers) obtained by a proper optimization process.
Through a systematic experimental analysis, three different types of biocomposites obtained with a suitable manufacturing process, such as random short fiber biocomposites, random discontinuous fibers biocomposite obtained through the preliminary manufacture of MAT fabrics, and unidirectional long fibers biocomposites obtained through the preliminary manufacture of unidirectional \u201cstitched\u201d fabrics, have been studied
Nonequilibrium readiness and precision of Gaussian quantum thermometers
The dimensionality of a thermometer is key in the design of quantum thermometry schemes. In general, the phenomenology that is typical of qubit-based quantum thermometry does not apply to infinite-dimensional ones. We analyze the dynamical and metrological features of nonequilibrium Gaussian quantum thermometers: On one hand, we highlight how quantum entanglement can enhance the readiness of composite Gaussian thermometers; on the other hand, we show that nonequilibrium conditions do not guarantee the best sensitivities in temperature estimation, thus suggesting the reassessment of some of the working principles underpinning quantum thermometry
Multiparameter quantum estimation of noisy phase shifts
Phase estimation is the most investigated protocol in quantum metrology, but
its performance is affected by the presence of noise, also in the form of
imperfect state preparation. Here we discuss how to address this scenario by
using a multiparameter approach, in which noise is associated to a parameter to
be measured at the same time as the phase. We present an experiment using
two-photon states, and apply our setup to investigating optical activity of
fructose solutions. Finally, we illustrate the scaling laws of the attainable
precisions with the number of photons in the probe state
Differences and similarities between SARS-CoV and SARS-CoV-2: spike receptor-binding domain recognition and host cell infection with support of cellular serine proteases
Novel severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) became pandemic by the end of March 2020. In contrast to the 2002–2003 SARS-CoV outbreak, which had a higher pathogenicity and lead to higher mortality rates, SARSCoV-2 infection appears to be much more contagious. Moreover, many SARS-CoV-2 infected patients are reported to develop low-titer neutralizing antibody and usually suffer prolonged illness, suggesting a more effective SARS-CoV-2 immune surveillance evasion than SARS-CoV. This paper summarizes the current state of art about the differences and similarities between the pathogenesis of the two coronaviruses, focusing on receptor binding domain, host cell entry and protease activation. Such differences may provide insight into possible intervention strategies to fight the pandemic
Diffusion tensor magnetic resonance imaging of prostate cancer
Purpose: To explore the feasibility of 3 T magnetic resonance (MR)
diffusion tensor imaging (DTI) and fiber tracking (FT) in patients
with prostate cancer.
Materials and methods: Thirty consecutive patients (mean age,
62.5 years) with biopsy proven prostate cancer underwent 3 T-MR
imaging (MRI) and DTI using a 6-channel external phased-array
coil before radical prostatectomy. Regions of interest of 14 pixels
were defined in tumors and nonaffected areas in the peripheral zone
(PZ) and central gland (CG), according to histopatology after radical
prostatectomy. Apparent diffusion coefficient (ADC) and fractional
anisotropy (FA) values were determined. Differences in mean ADC
and FA values among prostate cancer, normal PZ and CG were
compared by 2-sided Student t test. The predominant diffusion
direction of the prostate anisotropy was color coded on a directionally
encoded color (DEC) map. A 3D reconstruction of fiber tract
orientations of the whole prostate was determined using the continuous
tracking method. The overall image quality for tumor localization
and local staging was assessed in retrospective matching
with whole-mount section histopathology images. Nodules detected
at MRI were classified as matched lesions if tumor presence and
extension were evidenced at histopathology.
Results: For all the patients, the DTI sequence images were suitable
for the evaluation of the zonal anatomy of the prostate gland and the
tumor localization. Quantitative evaluation of the regions of interest
(ROIs) showed a mean ADC value significantly lower in the peripheral
neoplastic area (1.06 0.37 10 3 mm2/s) than in the
normal peripheral portion (1.95 0.38 10 3 mm2/s) (P 0.05).
The mean FA values calculated in the normal peripheral (0.47
0.04) and central area (0.41 0.08) were very similar (P 0.05).
The mean FA values in the neoplastic lesion (0.27 0.05) were
significantly lower (P 0.05) than in the normal peripheral area and
in the normal central and adenomyomatous area. DEC showed a
top-bottom type preferential direction in the peripheral but not in the
central area, with the tumor lesions reducing the diffusion coding
direction represented as color zones tending toward gray. Tractographic
analysis permitted good delineation of the prostate anatomy
(capsule outline, peripheral and central area borders) and
neoplastic lesion extension and capsule infiltration compared
with histopathology.
Conclusions: Three tesla DTI of the prostate gland is feasible and
has the potential for providing improved diagnostic information
Assessing Vegetation Decline Due to Pollution from Solid Waste Management by a Multitemporal Remote Sensing Approach
Nowadays, the huge production of Municipal Solid Waste (MSW) is one of the most strongly felt environmental issues. Consequently, the European Union (EU) delivers laws and regulations for better waste management, identifying the essential requirements for waste disposal operations and the characteristics that make waste hazardous to human health and the envi-ronment. In Italy, environmental regulations define, among other things, the characteristics of sites to be classified as “potentially contaminated”. From this perspective, the Basilicata region is cur-rently one of the Italian regions with the highest number of potentially polluted sites in proportion to the number of inhabitants. This research aimed to identify the possible effects of potentially toxic element (PTE) pollution due to waste disposal activities in three “potentially contaminated” sites in southern Italy. The area was affected by a release of inorganic pollutants with values over the thresholds ruled by national/European legislation. Potential physiological efficiency variations of vegetation were analyzed through the multitemporal processing of satellite images. Landsat 5 Thematic Mapper (TM) and Landsat 8 Operational Land Imager (OLI) images were used to calcu-late the trend in the Normalized Difference Vegetation Index (NDVI) over the years. The mul-titemporal trends were analyzed using the median of the non-parametric Theil–Sen estimator. Fi-nally, the Mann–Kendall test was applied to evaluate trend significance featuring areas according to the contamination effects on investigated vegetation. The applied procedure led to the exclu-sion of significant effects on vegetation due to PTEs. Thus, waste disposal activities during previ-ous years do not seem to have significantly affected vegetation around targeted sites
Nuclear factor ÎşB activity is increased in peripheral blood mononuclear cells of children affected by atopic and non-atopic eczema
Atopic and non-atopic eczema is an inflammatory cutaneous disease which is common in childhood and is associated with a dysregulation of the immune system. Many genes encoding immune receptors, cytokines, chemokines, chemokine receptors, and adhesion molecules involved in the development of the disease are under the control of transcription factors belonging to the nuclear factor (NF)-ÎşB family. To investigate the role of NF-ÎşB in the development of eczema, 20 children, affected by relapsing chronic eczema, were enrolled in this study. Eleven of the 20 children showed IgE immunoreactivity and had a positive prick test. The DNA binding activity of NF-ÎşB in nuclear extracts of the patients' peripheral blood mononuclear cells (PBMC) was examined by electrophoretic mobility shift assay. We found that basal NF-ÎşB-DNA binding activity in PBMC was significantly higher in the eczema patient group in comparison with the same parameter in the healthy age-matched control group. Moreover, we observed a significant correlation between NF-ÎşB-DNA binding activity and patients' clinical score (SCORAD). Based on these observations we speculate that NF-ÎşB can play an important role in the immunopathogenesis of eczema and therefore could be considered as a potential therapeutic target
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