316 research outputs found
Total orthotopic small bowel transplantation in swine under FK 506
Previous experimental studies in rodents and in dogs have established the efficacy of FK 506 in controlling the immunologic events following small bowel or multivisceral transplantation.1â5 To complete the assessment of FK 506 in experimental small bowel transplantation, we present here our experience with the frequently used swine model
Exploring Factors Influencing Changes in Incidence and Severity of Multisystem Inflammatory Syndrome in Children
Multisystem inflammatory syndrome (MIS-C) is a rare condition associated with COVID-19 affecting children, characterized by severe and aberrant systemic inflammation leading to nonspecific symptoms, such as gastrointestinal, cardiac, respiratory, hematological, and neurological disorders. In the last year, we have experienced a progressive reduction in the incidence and severity of MIS-C, reflecting the worldwide trend. Thus, starting from the overall trend in the disease in different continents, we reviewed the literature, hypothesizing the potential influencing factors contributing to the reduction in cases and the severity of MIS-C, particularly the vaccination campaign, the spread of different SARS-CoV-2 variants (VOCs), and the changes in human immunological response. The decrease in the severity of MIS-C and its incidence seem to be related to a combination of different factors rather than a single cause. Maturation of an immunological memory to SARS-CoV-2 over time, the implication of mutations of key amino acids of S protein in VOCs, and the overall immune response elicited by vaccination over the loss of neutralization of vaccines to VOCs seem to play an important role in this change
Nonlinear quantum model for atomic Josephson junctions with one and two bosonic species
We study atomic Josephson junctions (AJJs) with one and two bosonic species
confined by a double-well potential. Proceeding from the second quantized
Hamiltonian, we show that it is possible to describe the zero-temperature AJJs
microscopic dynamics by means of extended Bose-Hubbard (EBH) models, which
include usually-neglected nonlinear terms. Within the mean-field approximation,
the Heisenberg equations derived from such two-mode models provide a
description of AJJs macroscopic dynamics in terms of ordinary differential
equations (ODEs). We discuss the possibility to distinguish the Rabi,
Josephson, and Fock regimes, in terms of the macroscopic parameters which
appear in the EBH Hamiltonians and, then, in the ODEs. We compare the
predictions for the relative populations of the Bose gases atoms in the two
wells obtained from the numerical solutions of the two-mode ODEs, with those
deriving from the direct numerical integration of the Gross-Pitaevskii
equations (GPEs). Our investigations shows that the nonlinear terms of the ODEs
are crucial to achieve a good agreement between ODEs and GPEs approaches, and
in particular to give quantitative predictions of the self-trapping regime.Comment: Accepted for the publication in J. Phys. B: At. Mol. Opt. Phy
Quantum diffusion with disorder, noise and interaction
Disorder, noise and interaction play a crucial role in the transport
properties of real systems, but they are typically hard to control and study
both theoretically and experimentally, especially in the quantum case. Here we
explore a paradigmatic problem, the diffusion of a wavepacket, by employing
ultra-cold atoms in a disordered lattice with controlled noise and tunable
interaction. The presence of disorder leads to Anderson localization, while
both interaction and noise tend to suppress localization and restore transport,
although with completely different mechanisms. When only noise or interaction
are present we observe a diffusion dynamics that can be explained by existing
microscopic models. When noise and interaction are combined, we observe instead
a complex anomalous diffusion. By combining experimental measurements with
numerical simulations, we show that such anomalous behavior can be modeled with
a generalized diffusion equation, in which the noise- and interaction-induced
diffusions enter in an additive manner. Our study reveals also a more complex
interplay between the two diffusion mechanisms in regimes of strong interaction
or narrowband noise.Comment: 11 pages, 10 figure
Localization from quantum interference in one-dimensional disordered potentials
We show that the tails of the asymptotic density distribution of a quantum
wave packet that localizes in the the presence of random or quasiperiodic
disorder can be described by the diagonal term of the projection over the
eingenstates of the disordered potential. This is equivalent of assuming a
phase randomization of the off-diagonal/interference terms. We demonstrate
these results through numerical calculations of the dynamics of ultracold atoms
in the one-dimensional speckle and quasiperiodic potentials used in the recent
experiments that lead to the observation of Anderson localization for matter
waves [Billy et al., Nature 453, 891 (2008); Roati et al., Nature 453, 895
(2008)]. For the quasiperiodic case, we also discuss the implications of using
continuos or discrete models.Comment: 5 pages, 3 figures; minor changes, references update
Identification of Protein Tyrosine Phosphatase Receptor Gamma Extracellular Domain (sPTPRG) as a Natural Soluble Protein in Plasma
BACKGROUND:PTPRG is a widely expressed protein tyrosine phosphatase present in various isoforms. Peptides from its extracellular domain have been detected in plasma by proteomic techniques. We aim at characterizing the plasmatic PTPRG (sPTPRG) form and to identify its source.METHODOLOGY/PRINCIPAL FINDINGS:The expression of sPTPRG was evaluated in human plasma and murine plasma and tissues by immunoprecipitation and Western blotting. The polypeptides identified have an apparent Mr of about 120 kDa (major band) and 90 kDa (minor band) respectively. Full length PTPRG was identified in the 100.000
7g pelleted plasma fraction, suggesting that it was present associated to cell-derived vesicles (exosomes). The release of sPTPRG by HepG2 human hepatocellular carcinoma cell line was induced by ethanol and sensitive to metalloproteinase and not to Furin inhibitors. Finally, increased levels of the plasmatic 3c120 kDa isoform were associated with the occurrence of liver damage.CONCLUSIONS:These results demonstrate that sPTPRG represent a novel candidate protein biomarker in plasma whose increased expression is associated to hepatocyte damage. This observation could open a new avenue of investigation in this challenging field
InâDepth Immunological Typization of Children with Sickle Cell Disease: A Preliminary Insight into Its Plausible Correlation with Clinical Course and Hydroxyurea Therapy
Sickle cell disease (SCD) is a condition of functional hypoâ/aâsplenism in which predisposition to bacterial infections is only a facet of a wide spectrum of immuneâdysregulation disorders forming the clinical expression of a peculiar immunophenotype. The objective of this study was to perform an inâdepth immunophenotypical characterization of SCD pediatric patients, looking for plausible correlations between immunological biomarkers, the impact of hydroxyurea (HU) treatment and clinical course. This was an observational caseâcontrol study including 43 patients. The cohort was divided into two main groups, SCD subjects (19/43) and controls (24/43), differing in the presence/absence of an SCD diagnosis. The SCD group was split up into HU+ (12/19) and HUâ (7/19) subgroups, respectively receiving or not a concomitant HU treatment. The principal outcomes measured were differences in the immunophenotyping between SCD patients and controls through chiâsquared tests, tâtests, and Pearsonâs correlation analysis between clinical and immunological parameters. Leukocyte and neutrophil increase, Tâcell depletion with prevalence of memory Tâcell compartment, NK and BânaĂŻve subset elevation with memory and CD21low B subset reduction, and IgG expansion, significantly distinguished the SCD HUâ subgroup from controls, with naĂŻve T cells, switchedâmemory B cells and IgG maintaining differences between the SCD HU+ group and controls (pâvalue of <0.05). The mean CD4+ centralâmemory Tâcell% count was the single independent variable showing a positive correlation with vasoâocclusive crisis score in the SCD group (Pearsonâs R = 0.039). We report preliminary data assessing plausible clinical implications of baseline and HUârelated SCD immunophenotypical alterations, which need to be validated in larger samples, but potentially affecting hypoâ/aâsplenism immunoâchemoprophylactic recommendations
2,3,4-TribromoÂthioÂphene
In the title compound, C4HBr3S, there are two essentially planar molÂecules in the asymmetric unit. In the crystal structure, bifurcated CâHâŻBr hydrogen bonds link the molÂecules into chains. Weak BrâŻBr interÂactions [BrâŻBr = 3.634â
(4)â3.691â
(4)â
Ă
] then lead to undulating sheets in the bc plane
Atomic Josephson junction with two bosonic species
We study an atomic Josephson junction (AJJ) in presence of two interacting
Bose-Einstein condensates (BECs) confined in a double well trap. We assume that
bosons of different species interact with each other. The macroscopic wave
functions of the two components obey to a system of two 3D coupled
Gross-Pitaevskii equations (GPE). We write the Lagrangian of the system, and
from this we derive a system of coupled ordinary differential equations (ODE),
for which the coupled pendula represent the mechanic analogous. These
differential equations control the dynamical behavior of the fractional
imbalance and of the relative phase of each bosonic component. We perform the
stability analysis around the points which preserve the symmetry and get an
analytical formula for the oscillation frequency around the stable points. Such
a formula could be used as an indirect measure of the inter-species s-wave
scattering length. We also study the oscillations of each fractional imbalance
around zero and non zero - the macroscopic quantum self-trapping (MQST) - time
averaged values. For different values of the inter-species interaction
amplitude, we carry out this study both by directly solving the two GPE and by
solving the corresponding coupled pendula equations. We show that, under
certain conditions, the predictions of these two approaches are in good
agreement. Moreover, we calculate the crossover value of the inter-species
interaction amplitude which signs the onset of MQST.Comment: Accepted for the publication in J. Phys. B: At. Mol. Opt. Phy
- âŠ