Cassini composite infrared spectrometer: correcting an offset error and refining the pointing parameters for the midinfrared detectors.

Based on preflight laboratory testing, an unexpectedly large positional offset between the two midinfrared (mid-IR) detector arrays in the Cassini composite infrared spectrometer (CIRS) instrument has been noted in the literature. A much smaller offset was measured in-flight. We investigate this discrepancy by estimating several spatial relationships among the detectors and comparing these results with three independent data sets. This enables us to infer the probable cause of this offset and to derive a new reduced value. We comment on the effect that this change could have on previously published results involving CIRS data. We also present a graphical display of the arrays projected on the sky as CIRS would see it.

Cassini composite infrared spectrometer: correcting an offset error and refining the pointing parameters for the midinfrared detectors: publisher's note.

This publisher's note serves to correct Appl. Opt.62, 5882 (2023).APOPAI0003-693510.1364/AO.491970.

Raman and UVN+LWIR LIBS detection system for in-situ surface chemical identification.

Laser Induced Breakdown Spectroscopy (LIBS) in the Ultra Violet/Visible/Near-IR (UVN) spectral range is a powerful analytical tool that facilitates the interpretation of Raman spectroscopic data by providing additional details in elemental chemistry. To acquire the complete information of molecular vibrations for more accurate and precise chemical bonding and structural analysis, an ideal in situ optical sensing facility should be able to rapidly probe the broad vibrational dipole and polarizability responses of molecules by acquiring both Raman scattering and mid-IR emission spectroscopic signatures. Recently, the research team at Brimrose has developed a novel optical technology, Long-Wave IR (LWIR) LIBS. Critical experimental approaches were made to capture the infrared molecular emission signatures from vibrationally excited intact samples excited by laser-induced plasma in a LIBS event. LWIR LIBS is the only fieldable mid-IR emission spectroscopic technique to-date that that offers the same instrumental and analytical advantages of both UVN LIBS and Raman spectroscopy in in-situ stand-off field applications and can perform rapid and comprehensive molecular structure analysis without any sample-preparation.•A single excitation laser pulse is used to trigger both UVN and LWIR spectrometers simultaneously.•Time-resolved UVN-LWIR LIBS measurements showed the evolution of both atomic and molecular signature emissions of target compounds in the laser-induced plasma.•The technique was applied to the characterization of mineral and organic compounds in planetary analog samples.

Spectroscopic characterization of samples from different environments in a Volcano-Glacial region in Iceland: Implications for in situ planetary exploration.

Raman spectroscopy and laser induced breakdown spectroscopy (LIBS) are complementary techniques that together can provide a comprehensive characterization of geologic environments. For landed missions with constrained access to target materials on other planetary bodies, discerning signatures of life and habitability can be daunting, particularly where the preservation of organic compounds that contain the building blocks of life is limited. The main challenge facing any spectroscopy measurements of natural samples is the complicated spectra that often contain signatures for multiple components, particularly in rocks that are composed of several minerals with surfaces colonized by microbes. The goal of this study was to use the combination of Raman spectroscopy and LIBS to discern different environmental regimes based on the identification of minerals and biomolecules in rocks and sediments. Iceland is a terrestrial volcano-glacial location that offers a range of planetary analog environments, including volcanically active regions, extensive lava fields, geothermal springs, and large swaths of ice-covered terrain that are relevant to both rocky and icy planetary bodies. We combined portable VIS (532 nm) and NIR (785 nm) Raman spectroscopy, VIS micro-Raman spectroscopic mapping, and UV/VIS/NIR (200 - 1000 nm) and Mid-IR (5.6 - 10 µm, 1785 - 1000 cm-1) laser induced breakdown spectroscopy (LIBS) to characterize the mineral assemblages, hydrated components, and biomolecules in rock and sediment samples collected from three main sites in the volcanically active Kverkfjöll-Vatnajökull region of Iceland: basalt and basalt-hosted carbonate rind from Hveragil geothermal stream, volcanic sediments from the base of Vatnajökull glacier at Kverkfjöll, and lava from the nearby Holuhraun lava field. With our combination of techniques, we were able to identify major mineral polytypes typical for each sample set, as well as a large diversity of biomolecules typical for lichen communities across all samples. The anatase we observed using micro-Raman spectroscopic mapping of the lava compared with the volcanic sediment suggested different formation pathways: lava anatase formed authigenically, sediment anatase could have formed in association with microbial weathering. Mn-oxide, only detected in the carbonate samples, seems to have two possible formation pathways, either by fluvial or microbial weathering or both. Even with our ability to detect a wide diversity of biomolecules and minerals in all of the samples, there was not enough variation between each set to distinguish different environments based on the limited measurements done for this study.

Compact micromachined infrared bandpass filters for planetary spectroscopy.

The future needs of space-based, observational planetary and astronomy missions include low mass and small volume radiometric instruments that can operate in high-radiation and low-temperature environments. Here, we focus on a central spectroscopic component, the bandpass filter. We model the bandpass response of the filters to target the wavelength of the resonance peaks at 20, 40, and 60 µm and report good agreement between the modeled and measured response. We present a technique of using standard micromachining processes for semiconductor fabrication to make compact, free-standing, resonant, metal mesh filter arrays with silicon support frames. The process can be customized to include multiple detector array architectures, and the silicon frame provides lightweight mechanical support with low form factor.

Infrared limb sounding of Titan with the Cassini Composite InfraRed Spectrometer: effects of the mid-IR detector spatial responses.

The composite infrared spectrometer (CIRS) instrument on board the Cassini Saturn orbiter employs two 1x10 HgCdTe detector arrays for mid-infrared remote sensing of Titan's and Saturn's atmospheres. In this paper we show that the real detector spatial response functions, as measured in ground testing before launch, differ significantly from idealized "boxcar" responses. We further show that neglecting this true spatial response function when modeling CIRS spectra can have a significant effect on interpretation of the data, especially in limb-sounding mode, which is frequently used for Titan science. This result has implications not just for CIRS data analysis but for other similar instrumental applications.

Preventive cardioprotection of erythropoietin against doxorubicin-induced cardiomyopathy.

INTRODUCTION: Doxorubicin (DOX) is a highly effective chemotherapeutic agent related to dose-dependent cardiomyopathy. Recent evidence suggests that erythropoietin (EPO) can play a protective role in cardiovascular diseases by non-erythropoietic effects. In the present study, we tested the hypothesis that EPO may protect against DOX-induced cardiomyopathy through anti-apoptotic mechanisms both in vitro and in vivo. MATERIALS AND METHODS: Isolated neonatal Wistar rat cardiomyocytes were treated with vehicle, DOX with or without EPO, or EPO. Twenty-four hours later, the cells were used to determine cardiomyocyte apoptosis (TUNEL assay). Cardiomyopathy was induced in Wistar rats by intraperitoneal injections (IP) of DOX (2.5 mg/kg, six times for 2 weeks). EPO (2,500 U/kg, six times for 2 weeks) was administered simultaneously in the DOX+EPO group and the EPO group. Two weeks after the last administration, cardiac function was evaluated by echocardiography and invasive haemodynamic measurements. Rats were then sacrificed for histological and TUNEL analyses, with immunological detection for cardiac Troponin-T (cTnT), alpha-actinin, Bax and Bcl-2. RESULTS: EPO significantly ameliorated DOX-induced apoptosis of cultured cardiomyocytes as demonstrated by TUNEL assay. In the rat model, cardiac function significantly decreased in the DOX group. In contrast, the DOX+EPO group showed considerable improvement in cardiac function, inhibition of cardiomyocyte apoptosis, reduction of fibrosis, as well as up-regulation of Bcl-2 protein expression. CONCLUSIONS: Our results suggest that EPO exerts preventive cardioprotective effects on DOX-induced cardiomyopathy via anti-apoptotic pathways. The up-regulation of Bcl-2 protein expression may contribute to this.