3,188 research outputs found
Intensity correlations, entanglement properties and ghost imaging in multimode thermal-seeded parametric downconversion: Theory
We address parametric-downconversion seeded by multimode pseudo-thermal
fields. We show that this process may be used to generate multimode pairwise
correlated states with entanglement properties that can be tuned by controlling
the seed intensities. Multimode pseudo-thermal fields seeded
parametric-downconversion represents a novel source of correlated states, which
allows one to explore the classical-quantum transition in pairwise correlations
and to realize ghost imaging and ghost diffraction in regimes not yet explored
by experiments.Comment: 9 pages, 3 figure
Parallel spatial intensity correlations to decode random frequency-downconverted images
We record frequency-downconverted images that are chaotic, as they are obtained in a chi((2)) crystal from the interaction of two pulsed pseudo-thermal fields of which the one at the higher frequency encountered the imaged object. Spatial correlations of the intensity fluctuations in these chaotic images with the intensity of a single spatial Fourier component of the low-frequency input field, allow image retrieval if the number of records on which the ensemble-averages are calculated is suitably large. When it is too small to achieve a satisfactory result, we show that computing the correlations in parallel with different components of the low-frequency input field, shifting the correlation maps according to a rule suggested by 3D phase-matching, and averaging them, leads to the recovery of the downconverted image. The method can be used for secure and fast image transmission
Image transfer through a chaotic channel by intensity correlations
The three-wave mixing processes in a second-order nonlinear medium can be
used for imaging protocols, in which an object field is injected into the
nonlinear medium together with a reference field and an image field is
generated. When the reference field is chaotic, the image field is also chaotic
and does not carry any information about the object. We show that a clear image
of the object be extracted from the chaotic image field by measuring the
spatial intensity correlations between this field and one Fourier component of
the reference. We experimentally verify this imaging protocol in the case of
frequency downconversion.Comment: 17 pages, 7 figure
Rapid and MR-Independent IK1 activation by aldosterone during ischemia-reperfusion
In ST elevation myocardial infarction (STEMI) context, clinical studies have shown the deleterious
effect of high aldosterone levels on ventricular arrhythmia occurrence and cardiac
mortality. Previous in vitro reports showed that during ischemia-reperfusion, aldosterone
modulates K+ currents involved in the holding of the resting membrane potential (RMP).
The aim of this study was to assess the electrophysiological impact of aldosterone on IK1
current during myocardial ischemia-reperfusion. We used an in vitro model of “border zone”
using right rabbit ventricle and standard microelectrode technique followed by cell-attached
recordings from freshly isolated rabbit ventricular cardiomyocytes. In microelectrode experiments,
aldosterone (10 and 100 nmol/L, n=7 respectively) increased the action potential
duration (APD) dispersion at 90% between ischemic and normoxic zones (from 95±4ms to
116±6 ms and 127±5 ms respectively, P<0.05) and reperfusion-induced sustained premature
ventricular contractions occurrence (from 2/12 to 5/7 preparations, P<0.05). Conversely,
potassium canrenoate 100 nmol/L and RU 28318 1 ÎĽmol/l alone did not affect AP
parameters and premature ventricular contractions occurrence (except Vmax which was
decreased by potassium canrenoate during simulated-ischemia). Furthermore, aldosterone
induced a RMP hyperpolarization, evoking an implication of a K+ current involved in the
holding of the RMP. Cell-attached recordings showed that aldosterone 10 nmol/L quickly
activated (within 6.2±0.4 min) a 30 pS K+-selective current, inward rectifier, with pharmacological
and biophysical properties consistent with the IK1 current (NPo =1.9±0.4 in control vs
NPo=3.0±0.4, n=10, P<0.05). These deleterious effects persisted in presence of RU 28318,
a specific MR antagonist, and were successfully prevented by potassium canrenoate, a non
specific MR antagonist, in both microelectrode and patch-clamp recordings, thus indicating
a MR-independent IK1 activation. In this ischemia-reperfusion context, aldosterone induced
rapid and MR-independent deleterious effects including an arrhythmia substrate (increased
APD90 dispersion) and triggered activities (increased premature ventricular contractions
occurrence on reperfusion) possibly related to direct IK1 activation
The Determination of Nuclear Level Densities from Experimental Information -
A novel Information Theory based method for determining the density of states
from prior information is presented. The energy dependence of the density of
states is determined from the observed number of states per energy interval and
model calculations suggest that the method is sufficiently reliable to
calculate the thermal properties of nuclei over a reasonable temperature range.Comment: 7 pages + 6 eps figures, REVTEX 3.
Perinatal nutrient restriction reduces nephron endowment increasing renal morbidity in adulthood: A review
Perinatal malnutrition has been included among the causes of renal disease in adulthood. Here, we consider the relationships between early supply of specific nutrients (such as protein, fat, vitamins and electrolytes) and renal endowment. Prenatal and postnatal nutrition mismatch is also discussed. In addition, this article presents the role of nutrition of both mothers and pre-term infants on nephron endowment, with final practical considerations. (C) 2010 Elsevier Ireland Ltd. All rights reserved
“Bit Standard”- Bitcoin between reality and risks of a “halfway-money”
This work provides an explanation of the market underlying the evolution due to modern technologies and technical advances, especially in transactions. In this regard, the authors specify the aspect related to the creation of virtual currencies like bitcoin that can circulate thanks to the Blockchain system through miners\u2019 work. The authors consider areas related to the warnings on the use and exchange of virtual currencies. The aim is to conceptualize in a graphical way the current operational transaction in bitcoin through the existing exchange platforms. The authors try to attest the fickleness of the disintermediation ideal founding Bitcoin. The analysis purposed could be interesting and useful to provide a kind of interpretation of the phenomenon and a general overview about Bitcoin system
High Glucose Impairs Expression and Activation of MerTK in ARPE-19 Cells
MerTK (Mer Tyrosine Kinase) is a cell surface receptor that regulates phagocytosis of pho-toreceptor outer segments (POS) in retinal pigment epithelial (RPE) cells. POS phagocytosis is im-paired in several pathologies, including diabetes. In this study, we investigate whether hyperglyce-mic conditions may affect MerTK expression and activation in ARPE-19 cells, a retinal pigment epithelial cellular model. ARPE-19 cells were cultured in standard (CTR) or high-glucose (HG) me-dium for 24 h. Then, we analyzed: mRNA levels and protein expression of MerTK and ADAM9, a protease that cleaves the extracellular region of MerTK; the amount of cleaved Mer (sMer); and the ability of GAS6, a MerTK ligand, to induce MerTK phosphorylation. Since HG reduces miR-126 levels, and ADAM9 is a target of miR-126, ARPE-19 cells were transfected with miR-126 inhibitor or mimic; then, we evaluated ADAM9 expression, sMer, and POS phagocytosis. We found that HG reduced expression and activation of MerTK. Contextually, HG increased expression of ADAM9 and the amount of sMer. Overexpression of miR-126 reduced levels of sMer and improved phago-cytosis in ARPE-19 cells cultured with HG. In this study, we demonstrate that HG compromises MerTK expression and activation in ARPE-19 cells. Our results suggest that HG up-regulates ADAM9 expression, leading to increased shedding of MerTK. The consequent rise in sMer coupled to reduced expression of MerTK impairs binding and internalization of POS in ARPE-19 cells
Lineamenti morfologici e cartografia dei popolamenti bentonici di Rada della Reale nell'isola dell’Asinara (Sardegna NW)= Morphological elements and cartography of benthic community in Rada della Reale, Asinara Island (Sardinia NW)
A detailed investigation of bottom types in Rada della Reale has been carried out in 1998 as part of resources study of Asinara National Park. The study area, along 23 km of coastline between Punta Barbatossa and Punta Trabucato, has a surface of 15 km2. Detailed informattin on biotic communities in the area has been recorded and transferred in a thematic map together with geomorphological features. The main benthic community is represented by the Posidonia oceanica meadow, wlth a denslty up to 700-800 shootslm2. Other seagrasses like Cymodocea nodosa and Caulerpa prolifera are also present. In the mediolittoral zone assemblages of Patella ferruginea are of main importance.
Considering the great value of the area, in the future an integrated management strategy that improves conservation and enhances the value of the resources must be developed
Left atrial trajectory impairment in hypertrophic cardiomyopathy disclosed by geometric morphometrics and parallel transport
The analysis of full Left Atrium (LA) deformation and whole LA deformational trajectory in time has been poorly investigated and, to the best of our knowledge, seldom discussed in patients with Hypertrophic Cardiomyopathy. Therefore, we considered 22 patients with Hypertrophic Cardiomyopathy (HCM) and 46 healthy subjects, investigated them by three-dimensional Speckle Tracking Echocardiography, and studied the derived landmark clouds via Geometric Morphometrics with Parallel Transport. Trajectory shape and trajectory size were different in Controls versus HCM and their classification powers had high AUC (Area Under the Receiving Operator Characteristic Curve) and accuracy. The two trajectories were much different at the transition between LA conduit and booster pump functions. Full shape and deformation analyses with trajectory analysis enabled a straightforward perception of pathophysiological consequences of HCM condition on LA functioning. It might be worthwhile to apply these techniques to look for novel pathophysiological approaches that may better define atrio-ventricular interaction
- …