Programma di ray-tracing nel magnetoplasma ionosferico

Il pacchetto applicativo “IONORT” per il calcolo del ray-tracing può essere utilizzato dagli utenti che impiegano il sistema operativo Windows. È un programma la cui interfaccia grafica con l’utente è realizzata in MATLAB. In realtà, il programma lancia un eseguibile che integra il sistema d’equazioni differenziali scritto in linguaggio Fortran e ne importa l’output nel programma MATLAB, il quale genera i grafici e altre informazioni sul raggio. A completamento di questa premessa va detto che questo pacchetto, nella sua parte computazionale, è figlio di un programma di Jones e Stephenson del 1975, dal titolo “A versatile three-dimensional ray-tracing computer program for radio waves in the ionosphere”, il quale a sua volta si rifaceva principalmente a un programma di ray-tracing di Dudziak (1961) e di altri ricercatori quali Croft and Gregory (1963), ecc.. Pertanto, come tutti i recenti programmi di ray- tracing, questo è un programma fatto di programmi e non si può non menzionare qui la prima applicazione numerica di ray-tracing di Haeselgrove (1955). Attualmente questi programmi sono stati ottimizzati e adattati alle applicazioni dei radar oltre l’orizzonte - Over The Horizon, OTH – [Coleman, 1998][Nickish, 2008] sfruttando le potenzialità di potenti computer e periferiche per la presentazione e l’utilizzo real-time nel problema delle coordinate registration CR. In ultimo, si precisa che tutti i parametri di input, output e le modalità d’uso del pacchetto applicativo sviluppato saranno forniti nel manuale utente allegato al CD

Cell proliferation and oncogene expression after bile duct ligation in the rat: Evidence of a specific growth effect on bile duct cells

The proliferative response of the rat liver was measured after temporary or permanent total biliary obstruction (BDO) and in different regions after selective ligation of the lobar ducts draining the right 60% of the hepatic mass. The results were compared with those after 70% partial hepatectomy (PH). Cell proliferation was assessed globally by measuring DNA synthesis and stratified to the separate cell populations with cytostaining techniques that allowed distinction of hepatocytes, duct cells, and nonparenchymal cells (NPCs). In selected experimental groups, gene expression was determined of transforming growth factor-β1 (TGFβ-1), prothrombin, c-erb-B2, transforming growth factor alpha (TGFα), human Cyclophilin (CyP), and 28S ribosomal RNA. The stimulation of a proliferative response to total BDO required obstruction for longer than 24 hours, but after this deligation did not switch off regeneration. In the first week after permanent BDO, there was progressive infiltration of NPCs, fibrous linkage of some portal areas, and a crescendo of DNA synthesis that was obvious at 24 hours, maximal at 48 hours, and back nearly to baseline at 6 days. At the 2-day mark, the bile duct cells had a 17-fold increase in proliferation, accompanied by a threefold to fourfold increase in hepatocyte renewal. Little or no increase in expression of TGFα or the hepatocyte-specific prothrombin gene was detectable in the first 48 hours, whereas levels of the oncogene c-erb-B2 that is associated with cholangiocarcinoma were expressed from 48 to 96 hours. Livers subjected to regional BDO with or without immunosuppressive treatment with FK 506 and cyclosporine had an inflammatory reaction only on the side with ligated ducts. DNA synthesis increased in both the obstructed and freely draining lobes to approximately half the level that occurred after total BDO. The proliferation of the obstructed side was similar to the mixed duct cell/hepatocyte response after total BDO, but this almost exclusively involved duct cells on the freely draining side. In contrast to the findings after BDO, livers after PH regenerated maximally at 24 hours rather than 48 hours, had a predominantly noninflammatory hepatocyte as opposed to duct cell response, and had marked expression of the prothrombin and TGFα genes but only weakly and late of c-erb-B2 messenger RNA. The results show that the liver responds as a whole and in a biologically intelligent way to the nature of the injury inflicted on any part of it. It further implies the presence of humoral communications and control networks that assure organ homeostasis and relate this to total body homeostasis. © 1995

A method to test HF ray tracing algorithm in the ionosphere by means of the virtual time delay

It is well known that a 3D ray tracing algorithm furnishes the ray’s coordinates, the three components of the wave vector and the calculated group time delay of the wave along the path. The latter quantity can be compared with the measured group time delay to check the performance of the algorithm. Simulating a perfect reflector at an altitude equal to the virtual height of reflection, the virtual time delay is assumed as a real time delay. For a monotonic electronic density profile we find a very small relative difference between the calculated and the virtual delay for both analytic and numerical 3D electronic density models

EBV-associated mononucleosis does not induce long-term global deficit in T-cell responsiveness to IL-15

It has been reported that infectious mononucleosis (IM)-symptomatic primary Epstein-Barr virus infection produces a global down-regulation of interleukin-15 receptor-\u3b1 (IL-15R\u3b1) on T cells and natural killer cells associated with a defective IL-15 responsiveness that lasts for many years after the disease episode. In contrast with these results, our data indicate that, in the T-cell compartment derived from remote IM subjects, there is no quantitative or qualitative defect in the expression of the IL-15R\u3b1 chain and no deficit in T-cell responsiveness to IL-15. We observed efficient signal transduction, survival, and proliferation even in response to low IL-15 concentrations. These data are relevant and shed new light on the immune long-term response in IM subjects because they contradict the hypothesis that defects in Epstein-Barr virus-host immune balance may be correlated with a long-lasting global deficit in T-cell responsiveness to IL-15. \ua9 2009 by The American Society of Hematology

Modified simple cold storage of rat livers with UW solution

Rat livers were preserved with the conventional use of UW solution for 30,42, and 48 hr and compared with livers in which the vascular bed was expanded with an additional 10 to 60 ml UW/100 g liver. The extra UW, expressed as % liver weight, was entrapped during final portal infusion by tying off the supra- and infrahepatic inferior vena cava. A beneficial influence of the vascular expansion was most pronounced in the 40% group, with 10/10, 5/10, and 3/10 long-term survivors following transplantation after 30, 42, and 48 hr preservation versus 3/10 and 0/10 after 30 and 42 hr in the 0c/c controls. In separate experiments, surrogate indi-ces of preservation quality following reperfusion explained this effect. The 40%—and, to a lesser extent, 20%—livers had higher and more uniformly distributed portal blood flow, better tissue oxygenation, smaller increases in postperfusion liver enzymes, higher adenine nucleotides and energy charge, and less histopathologic evidence of hemorrhage and congestion. Pressure changes in the vena cava fluid sump in additional experiments indicated that retrograde infusion of the trapped UW solution occurred in all of the 10-60% groups during the first 6 hr with stable pressures of 1.5 to 3 cm H20 thereafter. Collectively, these data suggest that the much discussed selective vulnerability of the microvasculature of stored allografts is due in part (or principally) to its selective lack of long-term exposure to the UW solution, which drains out of the open vessels but not from the parenchyma. The potential clinical exploitation of this concept is discussed. © 1994 by Williams and Wilkins

Effects on in vivo and in vitro hepatocyte proliferation of methylprednisolone, azathioprine, mycophenolic acid, mizoribine, and prostaglandin E<inf>1</inf>

IF= 0.47

IONORT: a Windows software tool to calculate the HF ray tracing in the ionosphere

This paper describes an applicative software tool, named IONORT (IONOspheric Ray Tracing), for calculating a three-dimensional ray tracing of high frequency waves in the ionospheric medium. This tool runs under Windows operating systems and its friendly graphical user interface facilitates both the numerical data input/output and the two/three-dimensional visualization of the ray path. In order to calculate the coordinates of the ray and the three components of the wave vector along the path as dependent variables, the core of the program solves a system of six first order differential equations, the group path being the independent variable of integration. IONORT uses a three-dimensional electron density specification of the ionosphere, as well as by geomagnetic field and neutral particles-electrons collision frequency models having validity in the area of interest.Comment: 25 pages, 7 figures, 2 table

A narrative review with specific focus on its role in pregnancy

The novel coronavirus disease (COVID-19) is a challenge to every health system. Unfortunately, it is unlikely that this pandemic will disappear soon. No health system, with its present resources and workflow, is capable enough to deal with a full-blown wave of this pandemic. Acquisition of specific new skills may be fundamental in delivering appropriate health care for our patients. The gold standard for diagnosis of the COVID-19 infection is real-time reverse transcription polymerase chain reaction. Radiological investigations (chest X-ray or high-resolution computerized tomography [CT]) can be helpful both for diagnosis and management, but they have many limitations. Ultrasound has been suggested as a reliable and accurate tool for assessing the lungs in COVID-19 patients. Lung ultrasound (LUS) can show specific signs of inter-stitial pneumonia, which is characteristic of COVID-19 pulmonary infection. In addition, nonradiologist specialists with experience in ultrasound can be trained on LUS with a relatively rapid learning curve. In pregnancy, LUS can be particularly useful due to the avoidance of exposure to ionizing radiation. In this review, we present the advantages, techniques, and limitations of the use of LUS during the COVID-19 pandemic, with specific focus on pregnancy

Detection of a Functional Hybrid Receptor γc/GM-CSFRβ in Human Hematopoietic CD34+ Cells

A functional hybrid receptor associating the common γ chain (γc) with the granulocyte/macrophage colony-stimulating factor receptor β (GM-CSFRβ) chain is found in mobilized human peripheral blood (MPB) CD34+ hematopoietic progenitors, SCF/Flt3-L primed cord blood (CB) precursors (CBPr CD34+/CD56−), and CD34+ myeloid cell lines, but not in normal natural killer (NK) cells, the cytolytic NK-L cell line or nonhematopoietic cells. We demonstrated, using CD34+ TF1β cells, which express an interleukin (IL)-15Rα/β/γc receptor, that within the hybrid receptor, the GM-CSFRβ chain inhibits the IL-15–triggered γc/JAK3-specific signaling controlling TF1β cell proliferation. However, the γc chain is part of a functional GM-CSFR, activating GM-CSF–dependent STAT5 nuclear translocation and the proliferation of TF1β cells. The hybrid receptor is functional in normal hematopoietic progenitors in which both subunits control STAT5 activation. Finally, the parental TF1 cell line, which lacks the IL-15Rβ chain, nevertheless expresses both a functional hybrid receptor that controls JAK3 phosphorylation and a novel IL-15α/γc/TRAF2 complex that triggers nuclear factor κB activation. The lineage-dependent distribution and function of these receptors suggest that they are involved in hematopoiesis because they modify transduction pathways that play a major role in the differentiation of hematopoietic progenitors