100,676 research outputs found
High Range Resolution Multichannel DVB-T Passive Radar: Aerial Target Detections
No full textThe exploitation of multiple DVB-T channels for a passive radar system has been considered to enhance the radar range resolution. A preliminary study has focused on the AF analysis to verify the suitability of a multichannel DVB-T signal for radar applications. The theoretical study has been supported by preliminary measurements relative to three adjacent DVB-T channels. Experimental results in an aerial scenario through the use of SDR hardware have been carried out and showed a clear improvement in range resolution when using multichannel rather than single channel DVB-T signals. It may be proven in the near future that target classification of noncooperative target radar imaging will be enabled by a high resolution DVB-T passive radar that is obtained by exploiting multichannel DVB-T signals
Use of interleukin-2 in the management of haematological malignancies: focus on minimal residual disease. Mandelli F, Capria S, Vignetti M, Meloni G.
No full textInterleukin (IL)-2 is a glycoprotein lymphokine which induces proliferation of all subclasses of T-lymphocytes, natural killer cells and lymphokine activated killer cells, differentiation of cytotoxic cells and secretion of other cytokines, especially interferon-gamma. A fundamental property of IL-2 activated effector cells is to selectively lyse freshly isolated tumour cells. Work carried out on animal tumour models and application in human therapeutics has suggested the potential value of an immunotherapeutic approach in haematological malignancies, especially in the setting of minimal residual disease. Extensive phase I/II trials have been conducted in all haematological diseases, but the most interesting results have been obtained in acute myeloid leukaemia and non-Hodgkin's lymphoma, where the possibility of achieving partial and complete responses in patients with advanced disease has been reported. The feasibility and immunomodulatory effects of IL-2 treatment in patients with minimal residual disease after high-dose chemotherapy have also been explored. However, the heterogeneity of cases treated and administration schedules used does not allow definitive conclusions to be drawn about the true impact of IL-2 treatment on the prognosis of these patients. The clearly encouraging results reported in the literature deserve further investigation from a biological and clinical point of view; until the role of IL-2 in haematological malignancies has been identified, it should be used only in the investigative setting of clinical trials
High Resolution Multichannel DVB-T Passive Radar
No full textThe exploitation of multiple DVB-T channels for a passive radar system has been considered to enhance the radar range resolution. A preliminary study has focused on the AF analysis to verify the suitability of a multichannel DVB-T signal for radar applications. The theoretical study has been supported by preliminary measurements relative to three adjacent DVB-T channels. Experimental results in an aerial scenario through the use of SDR hardware have been carried out and showed a clear improvement in range resolution when using multichannel rather than single channel DVB-T signals. It may be proven in the near future that target classification of noncooperative target radar imaging will be enabled by a high resolution DVB-T passive radar that is obtained by exploiting multichannel DVB-T signals.</p
Target-borne ECM against OFDM-based Imaging Passive Radars
No full textPassive radars are notoriously robust to jamming because the receiver location cannot be detected. Moreover, the use of OFDM based reference signals further improves the robustness against jammers. Nevertheless, recent papers have shown that deception/spoofing-type of jamming may still be possible. The idea was to use a target-on-board deception jammer aimed at deceiving the receiver by preventing it from precisely locating and identifying the target when passive radar imaging is used. In this paper, the same authors test the proposed approach by using a measured DVB-T reference signal. A realistic scenario is emulated by using a multichannel DVB-T signal (three DVB-T channels- A bout 24 MHz bandwidth)
Passive ISAR With DVB-T Signals
No full textAs recently demonstrated, passive radars are able to detect and track targets by exploiting illuminators of opportunity. In this paper, it will be proven that the same concept can be extended to passive inverse synthetic aperture radar (P-ISAR) imaging. A suitable type of signal processing is proposed that is able to form P-ISAR images starting from range-Doppler maps, which represent the output of passive-radar signal processing. Multiple-channel digital television broadcasting (DVB)-T signals are used to demonstrate the concept as they provide enough range resolution to form meaningful ISAR images. The problem of grating lobes, which are generated by the DVB-T signal, is also addressed and solved.</p
Regulatory T Cells in the Immunodiagnosis and Outcome of Kidney Allograft Rejection
No full textAcute rejection (AR) is responsible for up to 12% of graft loss with the highest risk generally occurring during the first six months after transplantation. AR may be broadly classified into humoral as well as cellular rejection. Cellular rejection develops when donor alloantigens, presented by antigen-presenting cells (APCs) through class I or class II HLA molecules, activate the immune response against the allograft, resulting in activation of naive T cells that differentiate into subsets including cytotoxic CD8+ and helper CD4+ T cells type 1 (TH1) and TH2 cells or into cytoprotective immunoregulatory T cells (Tregs). The immune reaction directed against a renal allograft has been suggested to be characterized by two major components: a destructive one, mediated by CD4+ helper and CD8+ cytotoxic T cells, and a protective response, mediated by Tregs. The balance between these two opposite immune responses can significantly affect the graft survival. Many studies have been performed in order to define the role of Tregs either in the immunodiagnosis of transplant rejection or as predictor of the clinical outcome. However, information available from the literature shows a contradictory picture that deserves further investigation
DVB-T Passive Radar for Vehicles Detection in Urban Environment
No full textPassive radar systems exploit non-cooperative transmitter to detect targets in areas of interest. Some of the main advantages of such systems with respect to conventional radars include low cost architectures, low energy requirements and potentially null probability of intercept. In this paper a low-cost solution for vehicles detection making use of passive radar concept is presented. A Software Defined Radio (SDR) solution and commercial antennas have been used to realize a DVB-T passive radar demonstrator. An analysis of the DVB-T signal is firstly presented together with a study of its capability as radar waveform. Afterwards an experimental setup is presented and analysed and finally some results of targets detection are shown.</p
Letter, [Author unclear] to Paulina T. Merritt
No full textHandwritten letter to Paulina Merritt from an unknown author, October 1, 1876.
Passive ISAR imaging of ships by using DVB-T signals
No full textIn this paper, a Multichannel DVB-T based passive radar is exploited to provide the means to implement a Passive ISAR (P-ISAR) in an effective way. A framework for PISAR imaging is proposed and an algorithm is designed to obtain P-ISAR images from Range Doppler (RD) maps. The proposed algorithm is tested on real-data of ships collected by a PR demonstrator based on Commercial of the Shelf (COTS) components.</p
HIGH RANGE RESOLUTION MULTICHANNEL DVB-T PASSIVE RADAR
No full textA method for improving range resolution in passive radar system is to jointly use more than one transmission channel of the same illuminator of opportunity (IO). This paper specifically focuses on the exploitation of multiple adjacent digital video broadcasting-terrestrial (DVB-T) channels for achieving high-range resolution profiles with a passive radar system operating in air surveillance scenario. Firstly, we present an analysis of the ambiguity function obtained from a multichannel DVB-T source and a pre-processing technique able to improve the characteristics of the multichannel signal are presented. Afterwards, the experimental scenario is defined and detection results on aerial targets are shown
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