13 research outputs found
Larvicidal and repellent activity of essential oils from wild and cultivated Ruta chalepensis L. (Rutaceae) against Aedes albopictus Skuse (Diptera: Culicidae), an arbovirus vector
Rutaceae are widely recognized for their toxic
and repellent activity exerted against mosquitoes. In our
research, the essential oils extracted from fresh leaves of
wild and cultivated plants of Ruta chalepensis L. (Rutaceae)
were evaluated for larvicidal and repellent activity against
the Asian tiger mosquito, Aedes albopictus Skuse (Diptera:
Culicidae), currently the most invasive mosquito worldwide.
In this research, gas chromatography and gas chromatography–
mass spectrometry analyses of the essential oils
from wild and cultivated plants showed only quantitative
differences, in particular relatively to the amounts of ketone
derivatives, while the qualitative profile evidenced a similar
chemical composition. Both essential oils from wild and
cultivated R. chalepensis plants were able to exert a very
good toxic activity against A. albopictus larvae (wild plants,
LC50035.66 ppm; cultivated plants, LC50033.18 ppm), and
mortality was dosage dependent. These data are the first
evidence of the toxicity of R. chalepensis against mosquitoes.
Furthermore, the R. chalepensis essential oil from wild
plants was an effective repellent against A. albopictus, also
at lower dosages: RD50 was 0.000215 ÎĽL/cm2 of skin, while
RD90 was 0.007613 ÎĽL/cm2. Our results clearly evidenced
that the larvicidal and repellent activity of R. chalepensis
essential oil could be used for the development of new and
safer products against the Asian tiger mosquito
Microstrip silicon detectors for digital radiography
We present the first results obtained using a digital imaging system, operating at room temperature, developed for medical applications working with a standard mammographic beam
The Instrument of the Imaging X-Ray Polarimetry Explorer
While X-ray spectroscopy, timing, and imaging have improved much since 1962 when the first astronomical nonsolar source was discovered, especially wi the launch of the Newton/X-ray Multi-Mirror Mission, Rossi/X-ray Timing Explorer, and Chandra/Advanced X-ray Astrophysics Facility, the progress of X-ray polarimetry has been meager. This is in part due to the lack of sensitive polarization detectors, which in turn is a result of the fate of approved missions and because celestial X-ray sources appear less polarized than expected. Only one positive measurement has been available until now: the Orbiting Solar Observatory measured the polarization of the Crab Nebula in the 1970s. The advent of microelectronics techniques has allowed for designing a detector based on the photoelectric effect of gas in an energy range where the optics are efficient at focusing in X-rays. Here we describe the instrument, which is the major contribution of the Italian collaboration to the Small Explorer mission called IXPE, the Imaging X-ray Polarimetry Explorer, which will launch in late 2021. The instrument is composed of three detector units based on this technique and a detector service unit. Three mirror modules provided by Marshall Space Flight Center focus X-rays onto the detectors. We show the technological choices, their scientific motivation, and results from the calibration of the instrument. IXPE will perform imaging, timing, and energy-resolved polarimetry in the 2–8 keV energy band opening this window of X-ray astronomy to tens of celestial sources of almost all classes
The Imaging X-Ray Polarimetry Explorer (IXPE): Technical Overview II
The Imaging X-ray Polarimetry Explorer (IXPE) will add polarization to the properties (time, energy, and position) observed in x-ray astronomy. A NASA Astrophysics Small Explorer (SMEX) in partnership with the Italian Space Agency (ASI), IXPE will measure the 28-keV polarization of a few dozen sources during the first 2 years following its 2021 launch. The IXPE Observatory includes three identical x-ray telescopes, each comprising a 4-m-focal-length (grazingincidence) mirror module assembly (MMA) and a polarization-sensitive (imaging) detector unit (DU), separated by a deployable optical bench. The Observatorys Spacecraft provides typical subsystems (mechanical, structural, thermal, power, electrical, telecommunications, etc.), an attitude determination and control subsystem for 3-axis stabilized pointing, and a command and data handling subsystem communicating with the science instrument and the Spacecraft subsystems
The Imaging X-Ray Polarimetry Explorer (IXPE): technical overview II
The Imaging X-ray Polarimetry Explorer (IXPE) will add polarization to the properties (time, energy, and position) observed in x-ray astronomy. A NASA Astrophysics Small Explorer (SMEX) in partnership with the Italian Space Agency (ASI), IXPE will measure the 2–8-keV polarization of a few dozen sources during the first 2 years following its 2021 launch. The IXPE Observatory includes three identical x-ray telescopes, each comprising a 4-m-focal-length (grazingincidence) mirror module assembly (MMA) and a polarization-sensitive (imaging) detector unit (DU), separated by a deployable optical bench. The Observatory’s Spacecraft provides typical subsystems (mechanical, structural, thermal, power, electrical, telecommunications, etc.), an attitude determination and control subsystem for 3-axis stabilized pointing, and a command and data handling subsystem communicating with the science instrument and the Spacecraft subsystems
The Imaging X-Ray Polarimetry Explorer (IXPE): Pre-Launch
International audienceLaunched on 2021 December 9, the Imaging X-ray Polarimetry Explorer (IXPE) is a NASA Small Explorer Mission in collaboration with the Italian Space Agency (ASI). The mission will open a new window of investigation—imaging x-ray polarimetry. The observatory features three identical telescopes, each consisting of a mirror module assembly with a polarization-sensitive imaging x-ray detector at the focus. A coilable boom, deployed on orbit, provides the necessary 4-m focal length. The observatory utilizes a three-axis-stabilized spacecraft, which provides services such as power, attitude determination and control, commanding, and telemetry to the ground. During its 2-year baseline mission, IXPE will conduct precise polarimetry for samples of multiple categories of x-ray sources, with follow-on observations of selected targets