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- Dherbecourt, J. B., et al.
(author)
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Design and pre-development of an airborne multi-species differential absorption Lidar system for water vapor and HDO isotope, carbon dioxide, and methane observation
- 2021
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In: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE-Intl Soc Optical Eng.
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Conference paper (peer-reviewed)abstract
- We report on the current design and preliminary developments of the airborne Lidar Emitter and Multi-species greenhouse gases Observation iNstrument (LEMON), which is aiming at probing H2O and its isotope HDO at 1982 nm, CO2 at 2051 nm, and potentially CH4 at 2290 nm, with the Differential Absorption Lidar method (DIAL). The infrared emitter is based on the combination of two Nested Cavity OPOs (NesCOPOs) with a single optical parametric amplifier (OPA) line for high-energy pulse generation. This configuration is enabled by the use of high-aperture periodically poled KTP crystals (PPKTP), which provide efficient amplification in the spectral range of interest around 2 μm with slight temperature adjustments. The parametric stages are pumped with a Nd:YAG laser providing 200 mJ nanosecond double pulses at 75 Hz. According to parametric conversion simulations supported by current laboratory experiments, output energies in the 40 - 50 mJ range are expected in the extracted signal beam whilst maintaining a good beam quality (M2 < 2). The ruler for all the optical frequencies involved in the system is planned to be provided by a GPS referenced frequency comb with large mode spacing (1 GHz) against which the emitter output pulses can be heterodyned. The frequency precision measurement is expected to be better than 200 kHz for the optical frequencies of interest. The presentation will give an overview of the key elements of design and of preliminary experimental characterizations of sub-systems building blocks.
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- Dherbecourt, J. B., et al.
(author)
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Lidar Emitter and Multi-species greenhouse gases Observation iNstrument (LEMON) : advances on a multi-species differential absorption Lidar system
- 2022
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In: 73rd International Astronautical Congress, IAC 2022. - : International Astronautical Federation, IAF.
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Conference paper (peer-reviewed)abstract
- In the frame of LEMON project (Lidar Emitter and Multi-species greenhouse gases Observation iNstrument - European Union's Horizon 2020 research and innovation program, GA n°821868), we are developing a multi-species differential absorption Lidar (DIAL). The goal is to benefit from innovative technological developments in terms of optical emitter, spectral reference, to be able to address H2O and its isotope HDO at 1982 nm, CO2 at 2051 nm, and potentially CH4 at 2290 nm, for future ground-based range-resolved DIAL sensing, and with the prospect of future airborne integrated-path DIAL (IPDA). The infrared emitter is based on the combination of two specific, patented, no-seeder Nested Cavity OPOs (NesCOPOs) coupled to a single optical parametric amplifier (OPA) line for high energy pulses generation. Specific developments are also pursued on the frequency reference for the emitter, which is planned to be provided by a GPS referenced frequency comb against which the emitter output pulses can be heterodyned. Besides the instrument design, specific tests experiments have been carried out, covering a wide panel of activities: radiation testing of some critical components to assess the potential of some key components for future space applications, emitter and frequency reference testing, preliminary DIAL tests with laboratory test-beds and comparison with specific in-situ calibration instruments as well as additional innovative techniques evaluation for the emitter. The final instrument design was carried out and the sub-units are now being built.
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- Lomakin, Artem, et al.
(author)
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Spatial genomics maps the structure, nature and evolution of cancer clones
- 2022
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In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 611:7936, s. 594-602
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Journal article (peer-reviewed)abstract
- Genome sequencing of cancers often reveals mosaics of different subclones present in the same tumour. Although these are believed to arise according to the principles of somatic evolution, the exact spatial growth patterns and underlying mechanisms remain elusive. Here, to address this need, we developed a workflow that generates detailed quantitative maps of genetic subclone composition across whole-tumour sections. These provide the basis for studying clonal growth patterns, and the histological characteristics, microanatomy and microenvironmental composition of each clone. The approach rests on whole-genome sequencing, followed by highly multiplexed base-specific in situ sequencing, single-cell resolved transcriptomics and dedicated algorithms to link these layers. Applying the base-specific in situ sequencing workflow to eight tissue sections from two multifocal primary breast cancers revealed intricate subclonal growth patterns that were validated by microdissection. In a case of ductal carcinoma in situ, polyclonal neoplastic expansions occurred at the macroscopic scale but segregated within microanatomical structures. Across the stages of ductal carcinoma in situ, invasive cancer and lymph node metastasis, subclone territories are shown to exhibit distinct transcriptional and histological features and cellular microenvironments. These results provide examples of the benefits afforded by spatial genomics for deciphering the mechanisms underlying cancer evolution and microenvironmental ecology.
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