201 research outputs found
In-lab characterization of HYPSOS, a novel stereo hyperspectral observing system: first results
HYPSOS (HYPerspectral Stereo Observing System, patented) is a novel remote sensing instrument able to extract the spectral information from the two channels of a pushbroom stereo camera; thus it simultaneously provides 4D information, spatial and spectral, of the observed features. HYPSOS has been designed to be a compact instrument, compatible with small satellite applications, to be suitable both for planetary exploration as well for terrestrial environmental monitoring. An instrument with such global capabilities, both in terms of scientific return and needed resources, is optimal for fully characterizing the observed surface of investigation.
HYPSOS optical design couples a pair of folding mirrors to a modified three mirror anastigmat telescope for collecting the light beams from the optical paths of the two stereo channels; then, on the telescope focal plane, there is the entrance slit of an imaging spectrograph, which selects and disperses the light from the two stereo channels on a bidimensional detector. With this optical design, the two stereo channels share the large majority of the optical elements: this allowed to realize a very compact instrument, which needs much less resources than an equivalent system composed by a stereo camera and a spectrometer.
To check HYPSOS actual performance, we realized an instrument prototype to be operated in a laboratory environment. The laboratory setup is representative of a possible flight configuration: the light diffused by a surface target is collimated on the HYPSOS channel entrance apertures, and the target is moved with respect to the instrument to reproduce the in- flight pushbroom acquisition mode.
Here we describe HYPSOS and the ground support equipment used to characterize the instrument, and show the preliminary results of the instrument alignment activities
Characterization and calibration of VIS cameras for space applications - JANUS and HYPSOS systems
Optical instruments are fundamental tools of the space missions for Solar System exploration. They can differ both for the observed region of electromagnetic spectrum and for the type of instrument. However, they all have a common denominator: must be calibrated and characterized. Instruments on board space missions operate in harsh environments and suffer from thermomechanical stresses, but they must guarantee their capabilities. The calibration process allows to have a mapping between the external ambient and the data generated by the instrument observing it, providing information in physical units. The characterization process allows to have an understanding of how the single components work and of the whole system, improving the comprehension of the instrument itself. A well characterized and calibrated instrument will provide more reliable data, its behaviour will be more predictable and it allows to identify possible problems during its operative lifetime.
This thesis applies this theme to different types of instrument, and in different development phase: JANUS (Jovis Amorum ac Natorum Undique Scrutator), a high-resolution camera ready to be launched towards the Jovian system in April 2023 on board the ESA JUICE (JUpiter ICy moons Explorer), and HYPSOS (HYPerspectral Stereo Observing System), a stereo imaging spectrometer which has been realized in laboratory as a prototype with the goal to validate a new concept of instrument.
The first part of the thesis is dedicated to the activities conducted on JANUS, in particular about the analysis of the on ground calibrations data.
In Chapter 1 the JUICE mission, JANUS, its scientific objectives and technical solutions are described. It provides the context for the Chapter 2 and 3.
In Chapter 2 the methodologies applied for the analysis of the calibrationd data, discussion and results for radiometric, spectral and geometrical calibrations are presented. There is also an analysis of the detector performances (such as, offset stability, dark current, readout noise) and of an unexpected effect observed directly on the data.
Chapter 3 shows an analysis performed to identify scientifical interesting targets (Targets of Opportunity) potentially observable by JUICE (and in particular JANUS during the long interplanetary cruise toward the Jovian System.
The remaining Chapters describe the activities performed at CNR-IFN in Padua, to develop, to characterize and to integrate HYPSOS and the setup in the optical bench.
Chapter 4 describes the experiment, the instrument design and its working principle. Moreover, it provides the context for the following Chapters (5,6,7).
Chapter 5 is dedicated to the characterization activities performed on the two aspheric off-axis mirrros composing the HYPSOS' telescope, and on the selected diffraction grating.
Chapter 6 describes the adopted solutions on the optical bench for the experimental setup both in terms of optomechanical and control software.
Finally, Chapter 7 describes the characterization activities on the spectrometer (including a preliminar spectral calibration) and the methodologies used for the alignment of both the diffraction grating on the spectrometer and Three Mirror Anastigmat telescope of the instrument.Optical instruments are fundamental tools of the space missions for Solar System exploration. They can differ both for the observed region of electromagnetic spectrum and for the type of instrument. However, they all have a common denominator: must be calibrated and characterized. Instruments on board space missions operate in harsh environments and suffer from thermomechanical stresses, but they must guarantee their capabilities. The calibration process allows to have a mapping between the external ambient and the data generated by the instrument observing it, providing information in physical units. The characterization process allows to have an understanding of how the single components work and of the whole system, improving the comprehension of the instrument itself. A well characterized and calibrated instrument will provide more reliable data, its behaviour will be more predictable and it allows to identify possible problems during its operative lifetime.
This thesis applies this theme to different types of instrument, and in different development phase: JANUS (Jovis Amorum ac Natorum Undique Scrutator), a high-resolution camera ready to be launched towards the Jovian system in April 2023 on board the ESA JUICE (JUpiter ICy moons Explorer), and HYPSOS (HYPerspectral Stereo Observing System), a stereo imaging spectrometer which has been realized in laboratory as a prototype with the goal to validate a new concept of instrument.
The first part of the thesis is dedicated to the activities conducted on JANUS, in particular about the analysis of the on ground calibrations data.
In Chapter 1 the JUICE mission, JANUS, its scientific objectives and technical solutions are described. It provides the context for the Chapter 2 and 3.
In Chapter 2 the methodologies applied for the analysis of the calibrationd data, discussion and results for radiometric, spectral and geometrical calibrations are presented. There is also an analysis of the detector performances (such as, offset stability, dark current, readout noise) and of an unexpected effect observed directly on the data.
Chapter 3 shows an analysis performed to identify scientifical interesting targets (Targets of Opportunity) potentially observable by JUICE (and in particular JANUS during the long interplanetary cruise toward the Jovian System.
The remaining Chapters describe the activities performed at CNR-IFN in Padua, to develop, to characterize and to integrate HYPSOS and the setup in the optical bench.
Chapter 4 describes the experiment, the instrument design and its working principle. Moreover, it provides the context for the following Chapters (5,6,7).
Chapter 5 is dedicated to the characterization activities performed on the two aspheric off-axis mirrros composing the HYPSOS' telescope, and on the selected diffraction grating.
Chapter 6 describes the adopted solutions on the optical bench for the experimental setup both in terms of optomechanical and control software.
Finally, Chapter 7 describes the characterization activities on the spectrometer (including a preliminar spectral calibration) and the methodologies used for the alignment of both the diffraction grating on the spectrometer and Three Mirror Anastigmat telescope of the instrument
Chronic obstructive pulmonary disease (COPD): new insights on the events leading to pulmonary inflammation
The presence of a heterogeneous infiltrate of macrophages, neutrophils and CD8+ Tc1 cells is a characteristic feature in the lung of patients with chronic obstructive pulmonary disease (COPD). This paper points out the contribution of different inflammatory cells and mediators to the pathogenesis and natural history of COPD. We will comment on data suggesting that CD8 cytotoxic T cells with an activated Tc1 phenotype migrate from the secondary lymphoid tissue to pulmonary tissue damaged by smoke or infective agents. On the basis of the knowledge of the pathophysiology of immunologic events, drugs that can potentially block the inflammation leading to the disability of COPD are being investigated. Long-term study in a large number of patients with COPD will be needed to verify the impact of a number of anti-inflammatory compounds in this increasingly common disease
HIV and pulmonary immune responses.
The lung is a central organ in human immunodeficiency virus (HIV)-induced pathophysiology, becoming infected during the asymptomatic period of the disease. The presence of HIV elicits a discrete virus-specific cytotoxic T lymphocyte (CTL)-mediated immune response in the pulmonary microenvironment. Here, Carlo Agostini and colleagues provide a framework for understanding the mechanisms underlying the spread of the retrovirus and the consequent progression of disease in patients with AIDS-associated lung involvement
T-lymphocytes with gamma/delta T cell receptors in patients with AIDS and Pneumocystis carinii pneumonia.
HIV-1 and the lung. Infectivity, pathogenic mechanisms and cellular immune responses taking place in the lower respiratory tract.
New aspects of hypersensitivity pneumonitis
PURPOSE OF REVIEW:
Hypersensitivity pneumonitis (HP) represents a complex pulmonary disorder of varying intensity and clinical presentation, which is characterized by a diffuse Tc1 immune response of lung parenchyma and airways in patients previously sensitized to one of more than 300 etiologic agents that may favor the HP reaction. This review describes recent data that have clarified some of the events that govern the development of the hypersensitivity reaction following exposure to the causative agents involved in this disease.
RECENT FINDINGS:
A number of recent data clearly demonstrate that several cytokines and chemokines, which are secreted at sites of disease activity, participate in the pulmonary inflammatory responses taking place in the lung of patients with HP.
SUMMARY:
The past few years have seen outstanding advances in the understanding of immunologic and molecular events involved in the pathogenesis of HP. It is possible that these data could allow the discovery of therapeutic targets in individuals chronically exposed to HP antigens and evolving towards pulmonary fibrosis
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