A new concept of acousto-optic tunable filter-based near-infrared hyperspectral imager for planetary surface exploration.

In the past two decades, near-infrared (NIR) hyperspectral imaging instruments have revolutionized our conception of planetary surfaces in terms of evolution, geology, mineralogy, and alteration processes. The cornerstone of this remote analysis technique is the synergy between imagery, giving the geomorphological context of the observations, and NIR spectroscopy whose spectral range is sensitive to the main absorption features of most of the minerals present on planetary surfaces. The development of a generation of space instrument based on Acousto-Optic Tunable Filters (AOTFs) increases the capacity of these spectrometers to be set up in a variety of space probes. The ExoCam concept, developed at Institut d'Astrophysique Spatiale and profiting from the lab's previous experience (MicrOmega onboard Phobos-Grunt, Hayabusa 2 and ExoMars), thus, proposes for the first time to do hyperspectral imagery through a wide aperture AOTF (15 × 15 mm2) in the 0.95-3.6 µm spectral range. The characterization of this instrumental concept, led on a representative breadboard built for this purpose, showed that the acousto-optic diffraction preserves the image quality up to the diffraction/resolution limit over the whole field of view. The spectral resolution (from 2 to 25 nm over the spectral range) and accuracy of the instrument are also consistent with the identification of planetary surface minerals. This paper describes the ExoCam concept and objectives, the setup of an optical breadboard representative of a space instrument based on this concept, and the results of performance characterizations realized on the breadboard.

Pre-launch radiometric calibration of the infrared spectrometer onboard SuperCam for the Mars2020 rover.

Near-infrared spectroscopy has become a well-known remote sensing technique for the surface characterization of planetary objects. Among them, Mars was observed in the past by three imaging spectrometers from orbit. The Infrared Spectrometer/SuperCam instrument performs near-infrared spectroscopy from the martian surface for the first time, with a 1.15 mrad field of view, in the 1.3 µm-2.6 µm range, enabling the identification of a variety of mafic and altered minerals. Before integration aboard the rover, the spectrometer underwent a calibration campaign. Here, we report the radiometric and linearity responses of the instrument, including the optical and thermal setups used to perform them over its nominal range of operations, in terms of instrument detector temperatures and spectral range. These responses were constrained by accuracy requirements (20% in absolute radiometry, 1% in relative). The derived instrument transfer function fits within these requirements (<15% in absolute and <0.8% in relative) and shall be used to calculate the expected instrumental signal-to-noise ratio for typical observation scenarios of mineral mixtures expected to be found in the Jezero crater, and ultimately to retrieve the spectral properties of the regions of interest observed by the rover.

The surface composition of asteroid 162173 Ryugu from Hayabusa2 near-infrared spectroscopy.

The near-Earth asteroid 162173 Ryugu, the target of the Hayabusa2 sample-return mission, is thought to be a primitive carbonaceous object. We report reflectance spectra of Ryugu's surface acquired with the Near-Infrared Spectrometer (NIRS3) on Hayabusa2, to provide direct measurements of the surface composition and geological context for the returned samples. A weak, narrow absorption feature centered at 2.72 micrometers was detected across the entire observed surface, indicating that hydroxyl (OH)-bearing minerals are ubiquitous there. The intensity of the OH feature and low albedo are similar to thermally and/or shock-metamorphosed carbonaceous chondrite meteorites. There are few variations in the OH-band position, which is consistent with Ryugu being a compositionally homogeneous rubble-pile object generated from impact fragments of an undifferentiated aqueously altered parent body.

COMETARY SCIENCE. 67P/Churyumov-Gerasimenko surface properties as derived from CIVA panoramic images.

The structure and composition of cometary constituents, down to their microscopic scale, are critical witnesses of the processes and ingredients that drove the formation and evolution of planetary bodies toward their present diversity. On board Rosetta's lander Philae, the Comet Infrared and Visible Analyser (CIVA) experiment took a series of images to characterize the surface materials surrounding the lander on comet 67P/Churyumov-Gerasimenko. Images were collected twice: just after touchdown, and after Philae finally came to rest, where it acquired a full panorama. These images reveal a fractured surface with complex structure and a variety of grain scales and albedos, possibly constituting pristine cometary material.

Detection of hydrated silicates in crustal outcrops in the northern plains of Mars.

The composition of the ancient martian crust is a key ingredient in deciphering the environment and evolution of early Mars. We present an analysis of the composition of large craters in the martian northern plains based on data from spaceborne imaging spectrometers. Nine of the craters have excavated assemblages of phyllosilicates from ancient, Noachian crust buried beneath the plains' cover. The phyllosilicates are indistinguishable from those exposed in widespread locations in the southern highlands, demonstrating that liquid water once altered both hemispheres of Mars.

Hydrated silicate minerals on Mars observed by the Mars Reconnaissance Orbiter CRISM instrument.

Phyllosilicates, a class of hydrous mineral first definitively identified on Mars by the OMEGA (Observatoire pour la Mineralogie, L'Eau, les Glaces et l'Activitié) instrument, preserve a record of the interaction of water with rocks on Mars. Global mapping showed that phyllosilicates are widespread but are apparently restricted to ancient terrains and a relatively narrow range of mineralogy (Fe/Mg and Al smectite clays). This was interpreted to indicate that phyllosilicate formation occurred during the Noachian (the earliest geological era of Mars), and that the conditions necessary for phyllosilicate formation (moderate to high pH and high water activity) were specific to surface environments during the earliest era of Mars's history. Here we report results from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) of phyllosilicate-rich regions. We expand the diversity of phyllosilicate mineralogy with the identification of kaolinite, chlorite and illite or muscovite, and a new class of hydrated silicate (hydrated silica). We observe diverse Fe/Mg-OH phyllosilicates and find that smectites such as nontronite and saponite are the most common, but chlorites are also present in some locations. Stratigraphic relationships in the Nili Fossae region show olivine-rich materials overlying phyllosilicate-bearing units, indicating the cessation of aqueous alteration before emplacement of the olivine-bearing unit. Hundreds of detections of Fe/Mg phyllosilicate in rims, ejecta and central peaks of craters in the southern highland Noachian cratered terrain indicate excavation of altered crust from depth. We also find phyllosilicate in sedimentary deposits clearly laid by water. These results point to a rich diversity of Noachian environments conducive to habitability.

Coupled ferric oxides and sulfates on the Martian surface.

The Mars Exploration Rover (MER), Opportunity, showed that layered sulfate deposits in Meridiani Planum formed during a period of rising acidic ground water. Crystalline hematite spherules formed in the deposits as a consequence of aqueous alteration and were concentrated on the surface as a lag deposit as wind eroded the softer sulfate rocks. On the basis of Mars Express Observatoire pour la Minéralogie, l'Eau, les Glaces et l'Activité (OMEGA) orbital data, we demonstrate that crystalline hematite deposits are associated with layered sulfates in other areas on Mars, implying that Meridiani-like ground water systems were indeed widespread and representative of an extensive acid sulfate aqueous system.

Phyllosilicates on Mars and implications for early martian climate.

The recent identification of large deposits of sulphates by remote sensing and in situ observations has been considered evidence of the past presence of liquid water on Mars. Here we report the unambiguous detection of diverse phyllosilicates, a family of aqueous alteration products, on the basis of observations by the OMEGA imaging spectrometer on board the Mars Express spacecraft. These minerals are mainly associated with Noachian outcrops, which is consistent with an early active hydrological system, sustaining the long-term contact of igneous minerals with liquid water. We infer that the two main families of hydrated alteration products detected-phyllosilicates and sulphates--result from different formation processes. These occurred during two distinct climatic episodes: an early Noachian Mars, resulting in the formation of hydrated silicates, followed by a more acidic environment, in which sulphates formed.

Summer evolution of the north polar cap of Mars as observed by OMEGA/Mars Express.

The Observatoire pour la Minéralogie, l'Eau, les Glaces, et l'Activité (OMEGA) visible-infrared imaging spectrometer extensively observed regions of Mars with latitudes above 70 degrees N in late 2004 (heliocentric longitude from Ls 93 degrees to Ls 127 degrees ). The extent of water ice at the surface and the size of ice grains were monitored as a function of time. Bright, small-grained frost, which initially covered a large fraction of the polar cap, waned in favor of large-grained ice. In outlying regions, dominated by large-grained ice, the albedo increased over the period. Evaluating the dust content was model dependent. However, contamination of ice by dust was low.

Spectral reflectance and morphologic correlations in eastern Terra Meridiani, Mars.

The Mars Express Observatoire pour la Minéralogie, l'Eau, les Glaces, et l'Activité (OMEGA) hyperspectral image data covering eastern Terra Meridiani indicate the ubiquitous presence of molecular water in etched terrain materials that disconformably overlie heavily cratered terrains and underlie the hematite-bearing plains explored by the Opportunity rover. Identification of crystalline water in kieserite (MgSO4.H2O) is linked to materials exposed in a valley and plateau to the north of hematite-bearing plains. The mineralogical similarities between the etched terrain deposits examined with OMEGA data and the layered rocks examined by Opportunity imply that the ancient aqueous environments inferred from analyses of the rover data extend over regional scales.

Olivine and pyroxene diversity in the crust of Mars.

Data from the Observatoire pour la Minéralogie, l'Eau, les Glaces, et l'Activité (OMEGA) on the Mars Express spacecraft identify the distinct mafic, rock-forming minerals olivine, low-calcium pyroxene (LCP), and high-calcium pyroxene (HCP) on the surface of Mars. Olivine- and HCP-rich regions are found in deposits that span the age range of geologic units. However, LCP-rich regions are found only in the ancient Noachian-aged units, which suggests that melts for these deposits were derived from a mantle depleted in aluminum and calcium. Extended dark regions in the northern plains exhibit no evidence of strong mafic absorptions or absorptions due to hydrated materials.

Modulation of hepatic CYP2A1, CYP2C11, and CYP3A9 expression in adult rats by neonatal administration of tamoxifen.

To examine the effect of neonatal administration of tamoxifen on adult expression of hepatic cytochrome P-450 (CYP) enzymes and steroid 5alpha-reductase, male and female Sprague-Dawley rats were injected s.c. with tamoxifen (20 microg) or peanut oil (control) once daily at days 1 to 5 of age and sacrificed at 3 months of age. Neonatal tamoxifen treatment did not affect b.wt. or liver weight of adult male and female rats, but decreased testicular weight by approximately 40% in adult male rats. Neonatal administration of tamoxifen decreased hepatic microsomal testosterone 6beta- and 7alpha-hydroxylase activities in adult female rats whereas it did not alter steroid 5alpha-reductase activity. The same treatment increased testosterone 7alpha-hydroxylase activity, but did not affect testosterone 6beta-hydroxylase or steroid 5alpha-reductase activity in adult male rats. Immunoblot analysis indicated that neonatal tamoxifen treatment decreased CYP2C11 protein level by 26% and increased CYP2A1 protein content by 2.6-fold in adult male rats, whereas it had no effect on CYP3A or CYP2B protein expression. The reduction in the CYP3A-mediated testosterone 6beta-hydroxylase activity in adult female rats was accompanied by a decrease in CYP3A9 mRNA expression. Analysis of serum hormone levels indicated that neonatal exposure to tamoxifen resulted in a decrease in serum 17beta-estradiol concentration in adult female rats, whereas it did not alter serum testosterone concentration in adult male rats. In summary, treatment of neonatal rats with tamoxifen produced a long-lasting effect on hepatic CYP2A1, CYP2C11, and CYP3A9 expression in addition to testicular weight and serum 17beta-estradiol concentration.

Detection of Als proteins on the cell wall of Candida albicans in murine tissues.

A murine model of disseminated candidiasis was utilized to determine whether Candida albicans Als proteins are produced in vivo. The kidneys, spleen, heart, liver, and lungs were collected from mice inoculated with one of three C. albicans strains (SC5314, B311, or WO-1). Immunohistochemical analysis of murine tissues by using a rabbit polyclonal anti-Als serum indicated that Als proteins were produced by each C. albicans cell in the tissues examined. Patterns of staining with the anti-Als serum were similar among the C. albicans strains tested. These data indicated that Als protein production was widespread in disseminated candidiasis and that, despite strain differences in ALS gene expression previously noted in vitro, Als protein production in vivo was similar among C. albicans strains. The extensive production of Als proteins in vivo and their presence on the C. albicans cell wall position these proteins well for a role in host-pathogen interaction.

Molecular mechanisms of virulence in fungus-host interactions for Aspergillus fumigatus and Candida albicans.

Research on fungi that cause opportunistic infections has increased dramatically during the past few years, largely because these organisms cause significant morbidity and mortality. Most of this research has focused on defining the virulence factors produced by these pathogens, as well as developing methods for the diagnosis of fungal diseases. With regard to studies on the biology of Candida albicans, it is now possible to isolate genes, disrupt their expression, and observe the specific effects of gene disruption on virulence and growth of the organism. Moreover, growth and virulence of this pathogen is also being studied and the effect of environmental factors on gene expression investigated. This subject is especially important in view of the fact that C. albicans can colonize and invade a number of sites in the human body. Thus, its ability to grown in the oral and vaginal tracts, as well as in blood, requires the organism to adapt to a variety of environmental stresses. Here we present observations on the growth, morphogenesis and virulence of the opportunistic fungi C. albicans and Aspergillus fumigatus.

Initial uterine alterations caused by developmental exposure to tamoxifen.

Neonatal treatment of rodents with the widely used antiestrogen tamoxifen causes endometrial cancer and reproductive tract lesions reminiscent of the diethylstilbestrol (DES) syndrome. To evaluate the initial alterations induced in the developing uterus by tamoxifen or DES, neonatal Sprague-Dawley rat pups received 100 micrograms of tamoxifen (Group 1), 1 microgram of DES (Group 2), or vehicle (Group 3) subcutaneously on days 1 through 5, and their uteri were studied by light microscopy, 5-bromo-2' deoxyuridine immunohistochemistry, and computer-based morphometry. At Postnatal Day 6, epithelial hypertrophy (184.3% and 237.9% of controls) and myometrial thickening (151.9% and 180.0%) accounted for the uterotrophic effects of tamoxifen and DES. Evidence of secretory activity in epithelial cells, reduction of the epithelial BrdU-labeling index to 18.1% (tamoxifen) and 41.1% (DES) of controls, premature endometrial and myometrial differentiation, and the presence of eosinophils in both treatment groups suggested that tamoxifen exerted a DES-like estrogenic action on the developing uterus. These findings indicate that immediate epithelial and stromal-myometrial uterine alterations are found at Postnatal Day 6 after neonatal tamoxifen treatment.

PCR and RT-PCR analysis of infection and transcriptional activity of walleye dermal sarcoma virus (WDSV) in organs of adult walleyes (Stizostedion vitreum).

The pathogenesis of walleye dermal sarcoma virus (WDSV) infection was investigated in adult walleyes (Stizostedion vitreum). Three tumor-bearing and three tumor-free walleyes were collected in the spring from Oneida Lake, New York, and analyzed for viral infection and transcriptional activity. Specifically, the target organs for viral infection and supporting viral transcriptional activity were determined by assessing for the presence of WDSV DNA and RNA in the brain, liver, kidney, skin, and spleen. For each organ, WDSV DNA and RNA were detected using the polymerase chain reaction (PCR) and reverse transcription PCR (RT-PCR) respectively. Quantitative estimates of the number of viral DNA and RNA copies were obtained in each case by comparing the signal intensity of the sample to that of external controls. WDSV RNA/DNA ratios, based on those quantitative estimates, were computed for each organ. An RNA/DNA ratio of 3 was arbitrarily chosen as the threshold above which there was viral transcriptional activity. Viral DNA was found in all the organs examined from the three tumor-free walleyes. In those three tumor-free walleyes, low levels of WDSV RNA were detected in only one kidney and two spleen samples. In the three tumor-bearing walleyes, viral DNA was found in one brain, one kidney, two liver, and two skin samples. In contrast to the few organs from tumor-free walleyes in which WDSV RNA was detected, in tumor-bearing walleyes WDSV RNA was present in the one brain examined and in 2/3 kidney, 2/3 liver, 3/3 skin, and 3/3 spleen samples. A WDSV RNA/DNA ratio above 3 was obtained in all three tumor-bearing walleyes but in only one tumor-free fish. These data indicated that 1) both tumor-bearing and tumor-free walleyes were infected by WDSV, 2) many cell types were targeted by WDSV and supported viral transcription, and 3) tumor-bearing walleyes harbored a transcriptionally active WDSV, whereas tumor-free walleyes contained mostly silent WDSV DNA.

In situ hybridization and immunohistochemical study of walleye dermal sarcoma virus (WDSV) nucleic acids and proteins in spontaneous sarcomas of adult walleyes (Stizostedion vitreum).

Twenty-two anatomically independent dermal sarcomas from six adult walleye fish (Stizostedion vitreum) collected during the spring from Oneida Lake, New York, were examined by in situ hybridization and immunohistochemistry for the presence of walleye dermal sarcoma virus (WDSV). The viral RNA, DNA, and 90-kd protein were localized at the cellular level. Riboprobes complementary to the 5' terminal region of WDSV genome were used to detect viral nucleic acids. Rabbit polyclonal antiserum was generated against the 90-kd virus-associated antigen, presumably a product of the env gene, for immunohistochemical studies. Viral transcripts were detected in the neoplastic cells of all dermal sarcomas, in which they were generally abundant. Rare mononuclear inflammatory cells and cells within the epidermis also expressed viral RNA. In all sarcomas, low to moderate levels of viral DNA were present in all neoplastic and most mononuclear inflammatory and epidermal cells. Many neoplastic cells were immunopositive for the virus-associated protein. The distribution of immunopositive neoplastic cells mimicked approximately that of cells containing viral transcripts. The number of neoplastic cells with transcripts exceeded that of cells with protein, suggesting that productively infected neoplastic cells constituted a subset of the neoplastic cells that expressed WDSV transcripts. The viral antigen was also present within many mononuclear inflammatory cells. These data suggested that 1) dermal sarcomas were associated with elevated transcriptional activity of WDSV in the neoplastic cells and 2) the cell tropism of WDSV extended beyond the mesenchymal fibroblast-like neoplastic cells and included at least mononuclear inflammatory and epidermal cells.

Naturally occurring orocutaneous papillomas and carcinomas of brown bullheads (Ictalurus nebulosus) in New York State.

Ninety-four brown bullheads (Ictalurus nebulosus) with spontaneous orocutaneous neoplasms (papillomas and carcinomas) were studied grossly and by light microscopy. Of these 94 fish, 71 were selected from 505 fish examined macroscopically during field surveys and 23 were selected from those submitted for diagnostic study. Fish with neoplasms came from 17 locations throughout New York State: Buffalo River, Canaan Lake, Cazenovia Lake, Delta Lake, Fort Pond, Greenwood Lake, Hudson River, Lake George, Lake Tiorati, Lincoln Hall Pond. Lincoln Pond, Oneida Lake, Onondaga Lake, Rutland Pond, Salmon River, Silver Stream Reservoir and Swan Lake. The prevalence varied from 0 to 100%. Multiple neoplasms were more common (84/94, 89%) than solitary ones (10/94, 11%). In order of decreasing frequency, neoplasms arose on the head, especially the ventral aspect, the lower dental plate, the upper dental plate, the trunk, the barbels, the fins, the tongue, and the tail. Of the 38/94 brown bullheads (40%) with tumors in both upper and lower lips and dental plates, 24/38 (63%) had the tumors in opposition. Macroscopically, soft, pink or yellowish papillary masses protruded above the normal epithelial surfaces. Histologically, cutaneous and oral neoplasms originated from the morphologically similar Malpighian epithelial cells of the surface epithelia and from the outer cells of the enamel organ. Based on histopathologic criteria, cutaneous and oral neoplasms were considered the same disease in different anatomic locations. No apparent difference in biologic behavior was noted between cutaneous and oral neoplasms. The lesions apparently progressed from benign papilloma to locally invasive carcinoma (28/94, 30%). Neoplastic emboli were seen in one case, and no metastases were detected. There was no statistically significant difference between the susceptibility of males (20/57, 35%) and females (6/26, 23%) to carcinomas. An apparent correlation was noted between a higher frequency of malignant tumors and longer body size (3/13 fish [23%] < 30 cm, 17/54 fish [31%] 30-34 cm, and 7/18 fish [39%] > 34 cm).

A survey of epithelial odontogenic tumors and cysts in dogs and cats.

A retrospective histologic study of 12 canine and eight feline epithelial odontogenic tumors and cysts was conducted from oral masses (n = 3,917) obtained between 1980 and 1990. No sex or breed predilection was identified. Ameloblastoma was observed in two dogs (case Nos. 1, 2) 6 and 8 months of age. Calcifying epithelial odontogenic tumors were seen in a dog (case No. 3) and in two cats (case Nos. 4, 5) between 8 and 16 years of age. Ameloblastic fibroma (or fibroameloblastoma) was observed in cats (case Nos. 6-10) only. Inductive fibroameloblastoma was observed in four cats (case Nos. 6-9) up to 1 year of age, whereas ameloblastic fibroma was seen in a 14-year-old cat (case No. 10). A single ameloblastic odontoma was identified in a 20-month-old dog (case No. 11). Two complex odontomas occurred in a 6-month-old (case No. 12) and a 4-year-old (case No. 13) dog. Odontogenic cysts were identified in five dogs (case Nos. 14-18) aged 4.5 months to 16 years and in a 1-year-old cat (case No. 19) and have not been previously reported in these species. These cysts were lined by a stratified epithelium reminiscent of the appearance of ameloblastic epithelium. An odontogenic keratocyst with prominent central parakeratotic keratinization was identified in one 9-year-old female dog (case No. 20). Almost all epithelial odontogenic tumors were circumscribed, benign tumors that warranted a good prognosis for survival, although local recurrence may have followed (or may follow) incomplete excision. Calcifying epithelial odontogenic tumors may be locally invasive. Of six odontogenic cysts (case Nos. 14-19), two (case Nos. 15, 18) gave rise to basi-squamous carcinomas. The classification and behavior of epithelial odontogenic tumors and cysts in human beings, dogs, and cats are discussed.