Density functional calculations for 4He droplets

A novel density functional, which accounts correctly for the equation of state, the static response function and the phonon-roton dispersion in bulk liquid helium, is used to predict static and dynamic properties of helium droplets. The static density profile is found to exhibit significant oscillations, which are accompanied by deviations of the evaporation energy from a liquid drop behaviour in the case of small droplets. The connection between such oscillations and the structure of the static response function in the liquid is explicitly discussed. The energy and the wave function of excited states are then calculated in the framework of time dependent density functional theory. The new functional, which contains backflow-like effects, is expected to yield quantitatively correct predictions for the excitation spectrum also in the roton wave-length range.Comment: 15 pages, REVTEX, 10 figures available upon request or at http://anubis.science.unitn.it/~dalfovo/papers/papers.htm

PD-1 Blockade Modulates Functional Activities of Exhausted-Like T Cell in Patients With Cutaneous Leishmaniasis

Patients infected by Leishmania braziliensis develop debilitating skin lesions. The role of inhibitory checkpoint receptors (ICRs) that induce T cell exhaustion during this disease is not known. Transcriptional profiling identified increased expression of ICRs including PD-1, PDL-1, PDL-2, TIM-3, and CTLA-4 in skin lesions of patients that was confirmed by immunohistology where there was increased expression of PD-1, TIM-3, and CTLA-4 in both CD4^{+} and CD8^{+} T cell subsets. Moreover, PDL-1/PDL-2 ligands were increased on skin macrophages compared to healthy controls. The proportions PD1^{+}, but not TIM-3 or CTLA-4 expressing T cells in the circulation were positively correlated with those in the lesions of the same patients, suggesting that PD-1 may regulate T cell function equally in both compartments. Blocking PD-1 signaling in circulating T cells enhanced their proliferative capacity and IFN-γ production, but not TNF-α secretion in response to L. braziliensis recall antigen challenge in vitro. While we previously showed a significant correlation between the accumulation of senescent CD8^{+}CD45RA^{+}CD27^{-} T cells in the circulation and skin lesion size in the patients, there was no such correlation between the extent of PD-1 expression by circulating on T cells and the magnitude of skin lesions suggesting that exhausted-like T cells may not contribute to the cutaneous immunopathology. Nevertheless, we identified exhausted-like T cells in both skin lesions and in the blood. Targeting this population by PD-1 blockade may improve T cell function and thus accelerate parasite clearance that would reduce the cutaneous pathology in cutaneous leishmaniasis

Response of liquid 3He at finite temperatures

The random-phase-approximation (RPA) dynamical response of liquid 3 He at finite temperatures has been calculated using an effective density-dependent atom-atom interaction. The interaction contains a zero-range part of Skyrme type, supplemented by a weighted density approximation to account for short-range correlations, and a long-range effective interaction of Lennard-Jones type. The calculated zero-sound and paramagnon energy centroids agree reasonably with data, and the calculated strength exhibits a negative energy tail extending up to -0.5 meV, also in good agreement with existing data. We have found that opposite to what happens with zero sound, within RPA the paramagnon peak is rather insensitive to thermal broadening

Triplet pairing in fermionic droplets

We have investigated, in the L-S coupling scheme, the appearance of triplet pairing in fermionic droplets in which a single nl shell is active. The method is applied to a constant-strength model, for which we discuss the different phase transitions that take place as the number of particles in the shell is varied. Drops of 3He atoms can be plausible physical scenarios for the realization of the model

Bulk-plasmon dispersion relations in metals

Using an extended-random-phase-approximation sum-rule technique, we have investigated the bulk-plasmon dispersion relation, incorporating in a simple way exchange and correlation effects within the jellium model. The results obtained are compared with recent experimental findings. The key role played by exchange and correlation effects in improving the agreement between theory and experiment is stressed. The static polarizability has also been calculated as a function of q. The formulas can be easily modified to incorporate band-structure effects (through an intraband electron effective mass) and core-polarization effects (through a static dielectric constant)

Surface collective oscillations of metal clusters and spheres: Random-phase-approximation sum-rules approach

Using the once and thrice energy-weighted moments of the random-phase-approximation strength function, we have derived compact expressions for the average energy of surface collective oscillations of clusters and spheres of metal atoms. The L=0 volume mode has also been studied. We have carried out quantal and semiclassical calculations for Na and Ag systems in the spherical-jellium approximation. We present a rather thorough discussion of surface diffuseness and quantal size effects on the resonance energies

Fluorescence lifetime imaging for diagnostic and therapeutic intravital microscopy

Intravital imaging is now widely performed using wide-field microscopy, endoscopy, and state-of-the-art multiphoton microscopy for research and clinical assessment applications. Fluorescence lifetime imaging is increasingly being used as a complementary technology to greatly enhance the specificity and sensitivity in the analysis of the various fluorophores present within an intravital image. The fluorescence lifetime of a fluorophore. The fluorescence lifetime distribution for a fluorophore is an intrinsic property, arising from the emission of photons of light in the decaying to its original energy state after its molecules are excited by a specific wavelength of light and remain in an excited state for a range of times. This behavior for individual autofluorescent fluorophores, dyes, drugs, fluorescent proteins and antibodies is most frequently summarized in terms of their average fluorescence lifetime. Fluorescence lifetime differences are then used to identify and discriminate between molecules in various applications, including the assessment of drug distribution and metabolism, and in quantifying cell responses for toxicology. Fluorescence lifetime imaging microscopy (FLIM) and tomography involves the spatial representation of the fluorescent lifetimes of all molecules within image collected over a specified time period and resolution. Autofluorescence lifetime differences between normal and cancerous tissues have been used to define surgical margins during intraoperative surgery. Recent advances have enabled the rapid and robust collection of fluorescence lifetime information from tissues with high-resolution at video-rate speeds using endoscopic probes. Fluorescence lifetime imaging, combined with multi-spectral and anisotropic analysis, yields detailed redox state data from within a cell, arising from its metabolic state and enables intravital analysis of the transport and metabolism of fluorescent probes in cells. Intravital fluorescence lifetime imaging is becoming an indispensable diagnostic approach with broad therapeutic and clinical applications