417 research outputs found
Antiproton-deuteron annihilation at low energies
Recent experimental studies of the antiproton-deuteron system at low energies
have shown that the imaginary part of the antiproton-deuteron scattering length
is smaller than the antiproton-proton one. Two- and three-body systems with
strong annihilation are investigated and a mechanism explaining this unexpected
relation between the imaginary parts of the scattering lengths is proposed.Comment: 6 pages, 3 figures, to be published in The European Physical Journal
A proteomics approach to the study of bleomycin- induced lung fibrosis
Idiopathic pulmonary fibrosis (IPF) is the most severe lung fibrotic form and very few pharmacological therapies are available at present. Key events in the onset of
the disease are the activation of fibroblasts to myofibroblasts and the production and release of extracellular matrix (ECM) and molecular factors.
Primary murine lung fibroblasts were isolated and their activation induced by Bleomycin (BLM) treatment. Extracellular Vesicles (EV) were isolated and protein
extracted. Released soluble proteins (Secretome) and EV-derived proteins were reduced, alkylated and trypsin digested. A nano-LC-MS/MS SWATHTM approach
was used for the proteomics analyses.
Specific proteins with a putative role in the transition from physiological to fibrotic conditions, such as several matrix metalloproteinases (MMPs), osteopontin
(OPN), chitinase-3-like protein1 (CHI3L1) and CD44 resulted differentially released from BLM-treated fibroblasts as compared with untreated lung fibroblasts.
Our results provide further understanding of the pathophysiological features of lung fibrosis, and suggest specific target for pharmacological treatments
Transfusion-Associated Babesiosis after Heart Transplant
We describe a 54-year-old spleen-intact man with transfusion-associated Babesia microti infection after a heart transplant. Adult respiratory distress syndrome developed in the patient, and he required mechanical ventilation. Our experiences with this patient suggest that babesiosis should be considered in the differential diagnosis of transplant patients who have fever and hemolytic anemia
Full coherent control of nuclear spins in an optically pumped single quantum dot
Highly polarized nuclear spins within a semiconductor quantum dot (QD) induce
effective magnetic (Overhauser) fields of up to several Tesla acting on the
electron spin or up to a few hundred mT for the hole spin. Recently this has
been recognized as a resource for intrinsic control of QD-based spin quantum
bits. However, only static long-lived Overhauser fields could be used. Here we
demonstrate fast redirection on the microsecond time-scale of Overhauser fields
of the order of 0.5 T experienced by a single electron spin in an optically
pumped GaAs quantum dot. This has been achieved using full coherent control of
an ensemble of 10^3-10^4 optically polarized nuclear spins by sequences of
short radio-frequency (rf) pulses. These results open the way to a new class of
experiments using rf techniques to achieve highly-correlated nuclear spins in
quantum dots, such as adiabatic demagnetization in the rotating frame leading
to sub-micro K nuclear spin temperatures, rapid adiabatic passage, and spin
squeezing
Fluid observers and tilting cosmology
We study perfect fluid cosmological models with a constant equation of state
parameter in which there are two naturally defined time-like
congruences, a geometrically defined geodesic congruence and a non-geodesic
fluid congruence. We establish an appropriate set of boost formulae relating
the physical variables, and consequently the observed quantities, in the two
frames. We study expanding spatially homogeneous tilted perfect fluid models,
with an emphasis on future evolution with extreme tilt. We show that for
ultra-radiative equations of state (i.e., ), generically the tilt
becomes extreme at late times and the fluid observers will reach infinite
expansion within a finite proper time and experience a singularity similar to
that of the big rip. In addition, we show that for sub-radiative equations of
state (i.e., ), the tilt can become extreme at late times and
give rise to an effective quintessential equation of state. To establish the
connection with phantom cosmology and quintessence, we calculate the effective
equation of state in the models under consideration and we determine the future
asymptotic behaviour of the tilting models in the fluid frame variables using
the boost formulae. We also discuss spatially inhomogeneous models and tilting
spatially homogeneous models with a cosmological constant
Quantum flutter of supersonic particles in one-dimensional quantum liquids
The non-equilibrium dynamics of strongly correlated many-body systems
exhibits some of the most puzzling phenomena and challenging problems in
condensed matter physics. Here we report on essentially exact results on the
time evolution of an impurity injected at a finite velocity into a
one-dimensional quantum liquid. We provide the first quantitative study of the
formation of the correlation hole around a particle in a strongly coupled
many-body quantum system, and find that the resulting correlated state does not
come to a complete stop but reaches a steady state which propagates at a finite
velocity. We also uncover a novel physical phenomenon when the impurity is
injected at supersonic velocities: the correlation hole undergoes long-lived
coherent oscillations around the impurity, an effect we call quantum flutter.
We provide a detailed understanding and an intuitive physical picture of these
intriguing discoveries, and propose an experimental setup where this physics
can be realized and probed directly.Comment: 13 pages, 9 figure
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