413 research outputs found
Quantum transport including nonparabolicity and phonon scattering: application to silicon nanowires
In this work, the particular and combined influence of nonparabolicity and phonon scattering on the device characteristics of a triple-gate silicon nanowire is investigated. In addition, different approximations of the retarded self-energy for electron-phonon scattering are analyzed in terms of the electrostatics, current and computational cos
Does neuroinflammation turn on the flame in Alzheimer's disease? Focus on astrocytes
Data from animal models and Alzheimer's disease (AD) subjects provide clear evidence for an activation of inflammatory pathways during the pathogenetic course of such illness. Biochemical and neuropathological studies highlighted an important cause/effect relationship between inflammation and AD progression, revealing a wide range of genetic, cellular, and molecular changes associated with the pathology. In this context, glial cells have been proved to exert a crucial role. These cells, in fact, undergo important morphological and functional changes and are now considered to be involved in the onset and progression of AD. In particular, astrocytes respond quickly to pathology with changes that have been increasingly recognized as a continuum, with potentially beneficial and/or negative consequences. Although it is now clear that activated astrocytes trigger the neuroinflammatory process, however, the precise mechanisms have not been completely elucidated. Neuroinflammation is certainly a multi-faceted and complex phenomenon and, especially in the early stages, exerts a reparative intent. However, for reasons not yet all well known, this process goes beyond the physiologic control and contributes to the exacerbation of the damage. Here we scrutinize some evidence supporting the role of astrocytes in the neuroinflammatory process and the possibility that these cells could be considered a promising target for future AD therapies
Ramping fermions in optical lattices across a Feshbach resonance
We study the properties of ultracold Fermi gases in a three-dimensional
optical lattice when crossing a Feshbach resonance. By using a zero-temperature
formalism, we show that three-body processes are enhanced in a lattice system
in comparison to the continuum case. This poses one possible explanation for
the short molecule lifetimes found when decreasing the magnetic field across a
Feshbach resonance. Effects of finite temperatures on the molecule formation
rates are also discussed by computing the fraction of double-occupied sites.
Our results show that current experiments are performed at temperatures
considerably higher than expected: lower temperatures are required for
fermionic systems to be used to simulate quantum Hamiltonians. In addition, by
relating the double occupancy of the lattice to the temperature, we provide a
means for thermometry in fermionic lattice systems, previously not accessible
experimentally. The effects of ramping a filled lowest band across a Feshbach
resonance when increasing the magnetic field are also discussed: fermions are
lifted into higher bands due to entanglement of Bloch states, in good agreement
with recent experiments.Comment: 9 pages, 7 figure
Impact of CFTR Modulators on the Impaired Function of Phagocytes in Cystic Fibrosis Lung Disease
Cystic fibrosis (CF), the most common genetically inherited disease in Caucasian populations, is a multi-systemic life-threatening autosomal recessive disorder caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. In 2012, the arrival of CFTR modulators (potentiators, correctors, amplifiers, stabilizers, and read-through agents) revolutionized the therapeutic approach to CF. In this review, we examined the physiopathological mechanism of chronic dysregulated innate immune response in the lungs of CF patients with pulmonary involvement with particular reference to phagocytes, critically analyzing the role of CFTR modulators in influencing and eventually restoring their function. Our literature review highlighted that the role of CFTR in the lungs is crucial not only for the epithelial function but also for host defense, with particular reference to phagocytes. In macrophages and neutrophils, the CFTR dysfunction compromises both the intricate process of phagocytosis and the mechanisms of initiation and control of inflammation which then reverberates on the epithelial environment already burdened by the chronic colonization of pathogens leading to irreversible tissue damage. In this context, investigating the impact of CFTR modulators on phagocytic functions is therefore crucial not only for explaining the underlying mechanisms of pleiotropic effects of these molecules but also to better understand the physiopathological basis of this disease, still partly unexplored, and to develop new complementary or alternative therapeutic approaches
Silica Meets Tannic Acid: Designing Green Nanoplatforms for Environment Preservation
Hybrid tannic acid-silica-based porous nanoparticles, TA-SiO(2) NPs, have been synthesized under mild conditions in the presence of green and renewable tannic acid biopolymer, a glycoside polymer of gallic acid present in a large part of plants. Tannic acid (TA) was exploited as both a structuring directing agent and green chelating site for heavy metal ions recovery from aqueous solutions. Particles morphologies and porosity were easily tuned by varying the TA initial amount. The sample produced with the largest TA amount showed a specific surface area an order of magnitude larger than silica nanoparticles. The adsorption performance was investigated by using TA-SiO(2) NPs as adsorbents for copper (II) ions from an aqueous solution. The effects of the initial Cu(2+) ions concentration and the pH values on the adsorption capability were also investigated. The resulting TA-SiO(2) NPs exhibited a different adsorption behaviour towards Cu(2+), which was demonstrated through different tests. The largest adsorption (i.e., ~50 wt% of the initial Cu(2+) amount) was obtained with the more porous nanoplatforms bearing a higher final TA content. The TA-nanoplatforms, stable in pH value around neutral conditions, can be easily produced and their use would well comply with a green strategy to reduce wastewater pollution
I am Robot, Your Health Adviser for Older Adults: Do You Trust My Advice?
Artificial intelligence and robotic solutions are seeing rapid development for use across multiple occupations and sectors, including health and social care. As robots grow more prominent in our work and home environments, whether people would favour them in receiving useful advice becomes a pressing question. In the context of human–robot interaction (HRI), little is known about people’s advice-taking behaviour and trust in the advice of robots. To this aim, we conducted an experimental study with older adults to measure their trust and compliance with robot-based advice in health-related situations. In our experiment, older adults were instructed by a fictional human dispenser to ask a humanoid robot for advice on certain vitamins and over-the-counter supplements supplied by the dispenser. In the first experimented condition, the robot would give only information-type advice, i.e., neutral informative advice on the supplements given by the human. In the second condition, the robot would give recommendation-type advice, i.e., advice in favour of more supplements than those suggested initially by the human. We measured the trust of the participants in the type of robot-based advice, anticipating that they would be more trusting of information-type advice. Moreover, we measured the compliance with the advice, for participants who received robot-based recommendations, and a closer proxy of the actual use of robot health advisers in home environments or facilities in the foreseeable future. Our findings indicated that older adults continued to trust the robot regardless of the type of advice received, highlighting a type of protective role of robot-based recommendations on their trust. We also found that higher trust in the robot resulted in higher compliance with its advice. The results underpinned the likeliness of older adults welcoming a robot at their homes or health facilities
Earth-Moon Lagrangian points as a testbed for general relativity and effective field theories of gravity
We first analyse the restricted four-body problem consisting of the Earth, the Moon and the Sun as the primaries and a spacecraft as the planetoid. This scheme allows us to take into account the solar perturbation in the description of the motion of a spacecraft in the vicinity of the stable Earth-Moon libration points L4 and L5 both in the classical regime and in the context of effective field theories of gravity. A vehicle initially placed at L4 or L5 will not remain near the respective points. In particular, in the classical case the vehicle moves on a trajectory about the libration points for at least 700 days before escaping away. We show that this is true also if the modified long-distance Newtonian potential of effective gravity is employed. We also evaluate the impulse required to cancel out the perturbing force due to the Sun in order to force the spacecraft to stay precisely at L4 or L5. It turns out that this value is slightly modified with respect to the corresponding Newtonian one. In the second part of the paper, we first evaluate the location of all Lagrangian points in the Earth-Moon system within the framework of general relativity. For the points L4 and L5, the corrections of coordinates are of order a few millimeters and describe a tiny departure from the equilateral triangle. After that, we set up a scheme where the theory which is quantum corrected has as its classical counterpart the Einstein theory, instead of the Newtonian one. In other words, we deal with a theory involving quantum corrections to Einstein gravity, rather than to Newtonian gravity. By virtue of the effective-gravity correction to the long-distance form of the potential among two point masses, all terms involving the ratio between the gravitational radius of the primary and its separation from the planetoid get modified. Within this framework, for the Lagrangian points of stable equilibrium, we find quantum corrections of order two millimeters, whereas for Lagrangian points of unstable equilibrium we find quantum corrections below a millimeter. In the latter case, for the point L1, general relativity corrects Newtonian theory by 7.61 meters, comparable, as an order of magnitude, with the lunar geodesic precession of about 3 meters per orbit. The latter is a cumulative effect accurately measured at the centimeter level through the lunar laser ranging positioning technique. Thus, it is possible to study a new laser ranging test of general relativity to measure the 7.61-meter correction to the L1 Lagrangian point, an observable never used before in the Sun-Earth-Moon system. Performing such an experiment requires controlling the propulsion to precisely reach L1, an instrumental accuracy comparable to the measurement of the lunar geodesic precession, understanding systematic effects resulting from thermal radiation and multi-body gravitational perturbations. This will then be the basis to consider a second-generation experiment to study deviations of effective field theories of gravity from general relativity in the Sun-Earth-Moon system
Analisi globale sul settore degli emoderivati
Indice: Il settore farmaceutico - L'offerta e la distribuzione dei farmaci - I consumi farmaceutici - Gli emoderivati - La struttura della domanda - La struttura dell'offert
Betting on Yourself: A Decision Model for Human Resource Allocation Enriched With Self-Assessment of Soft Skills and Preferences
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