High frequency Lunar Penetrating Radar quality control, editing and processing of Chang'E-4 lunar mission.

Chinese lunar landing mission Chang'E-4 reached the far side of the Moon in January 2019 and has been providing unprecedented Lunar Penetrating Radar data able to explore the lunar subsurface down to more than 40 m (with its more resolutive high frequency band). Data are periodically released to the scientific community in raw PDS4 format. Here we provide different versions of the radar dataset after editing (i.e. pre-processing), partial, and full processing in order to provide a complete ready-to-use dataset to end-users (data collected since 4th January 2019 until 27th March 2023) which can be directly exploited for analysis, interpretation, inversion, as well as integration with imagery or other information. In particular, we implemented an efficient and objective way to remove duplicated traces representing more than 90% of original data, as well as a processing flow able to retain all the original data information, while avoiding redundancies. The provided datasets can be implemented with future data releases and straightforwardly exploited for any future analysis.

The pre-launch on-ground characterization of Ma_MISS spectrometer for ExoMars-Rosalind Franklin Rover mission. II. Radiometric calibration.

The Ma_MISS miniaturized spectrometer is integrated within the Drilling System of the ExoMars Rosalind Franklin Rover for Mars exploration. Here we focus on the on ground calibration campaign to obtain radiometric and linearity calibrations of the Ma_MISS instrument, while the first paper dealt with the spectral calibration [De Angelis et al., Rev. Sci. Instrum. 93, 123704 (2022)]. The experimental setup used to carry out radiometric calibration is described, as are the methods used for data processing and key parameter retrieval. In particular, the Spectrometer Transfer Function (Responsivity), Signal-to-Noise Ratio, and detector linearity are determined. In a third paper [De Sanctis et al., Planet. Sci. J. 3, 142 (2022)], validation of the Ma_MISS calibration results through spectral measurements performed on rock and synthetic targets during the radiometric calibration campaign is described.

Constraining the Rosalind Franklin Rover/Ma_MISS Instrument Capability in the Detection of Organics.

The Mars Multispectral Imager for Subsurface Studies (Ma_MISS) instrument is a miniaturized visible and near-infrared spectrometer that is integrated into the drilling system of the ESA Rosalind Franklin rover, which is devoted to subsurface exploration on Mars. Ma_MISS will acquire spectral data on the Martian subsurface from excavated borehole walls. The spectral data collected by Ma_MISS on unexposed rocks will be crucial for determination of the composition of subsurface rocks and optical and physical properties of materials (i.e., grain size). Ma_MISS will further contribute to a reconstruction of the stratigraphic column and acquire data on subsurface geological processes. Ma_MISS data may also inform with regard to the presence of potential biomarkers in the subsurface, given the presence of organic matter that may affect some spectral parameters. In this framework, we performed a wide range of measurements using the laboratory model of the Ma_MISS to investigate mineral/organic mixtures in different proportions. We prepared mixtures by combining kaolinite and nontronite with glycine, asphaltite, polyoxymethylene, and benzoic acid. These organic compounds show different spectral characteristics in the visible and near-infrared; therefore their presence can be detected by the Ma_MISS instrument. Our results indicate that the Ma_MISS instrument can detect organic material down to abundances of around 1 wt %. In particular, the data collected on low-concentration mixtures show that, by analyzing sediments with a grain size smaller than the Ma_MISS spatial resolution, the instrument can still discern those points where organic matter is present from points with exclusive mineral composition. The results also show that a collection of multiple contiguous measurements on a hypothetical borehole wall could help indicate the presence of organic matter in clay-rich soils if present.

Correction of the VIR-visible dataset from the Dawn mission at Vesta.

This work describes the correction method applied to the dataset acquired at the asteroid (4) Vesta by the visible channel of the visible and infrared mapping spectrometer. The rising detector temperature during data acquisitions in the visible wavelengths leads to a spectral slope increase over the whole spectral range. This limits the accuracy of the studies of the Vesta surface in this wavelength range. Here, we detail an empirical method to correct for the visible detector temperature dependency while taking into account the specificity of the Vesta dataset.

Correction of the VIR-visible data set from the Dawn mission.

Data acquired at Ceres by the visible channel of the Visible and InfraRed mapping spectrometer (VIR) on board the NASA Dawn spacecraft are affected by the temperatures of both the visible (VIS) and the infrared (IR) sensors, which are, respectively, a charged coupled device and a HgCdTe array. The variations of the visible channel temperatures measured during the sessions of acquisitions are correlated with the variations in the spectral slope and shape for all the mission phases. The IR channel temperature is more stable during the acquisitions; nonetheless, it is characterized by a bimodal distribution whether the cryocooler (and, therefore, the IR channel) is used or not during the visible channel operations. When the infrared channel temperature is high (175 K, i.e., not in use and with the cryocooler off), an additional negative slope and a distortion are observed in the spectra of the visible channel. We developed an empirical correction based on a reference spectrum for the whole dataset; it is designed to correct the two issues related to the sensor temperatures that we have identified. The reference spectrum is calculated to be representative of the global Ceres' surface. It is also made of the data acquired when the visible and infrared channel temperatures are equal to the ones measured during an observation of the Arcturus star by VIR, which is consistent with several ground-based observations. The developed correction allows reliable analysis and mapping to be performed by minimizing the artifacts induced by fluctuations of the VIS temperature. Thanks to this correction, a direct comparison between different mission phases during which the VIR experienced different visible and infrared channel temperatures is now possible.

Radar evidence of subglacial liquid water on Mars.

The presence of liquid water at the base of the martian polar caps has long been suspected but not observed. We surveyed the Planum Australe region using the MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) instrument, a low-frequency radar on the Mars Express spacecraft. Radar profiles collected between May 2012 and December 2015 contain evidence of liquid water trapped below the ice of the South Polar Layered Deposits. Anomalously bright subsurface reflections are evident within a well-defined, 20-kilometer-wide zone centered at 193°E, 81°S, which is surrounded by much less reflective areas. Quantitative analysis of the radar signals shows that this bright feature has high relative dielectric permittivity (>15), matching that of water-bearing materials. We interpret this feature as a stable body of liquid water on Mars.

Localized aliphatic organic material on the surface of Ceres.

Organic compounds occur in some chondritic meteorites, and their signatures on solar system bodies have been sought for decades. Spectral signatures of organics have not been unambiguously identified on the surfaces of asteroids, whereas they have been detected on cometary nuclei. Data returned by the Visible and InfraRed Mapping Spectrometer on board the Dawn spacecraft show a clear detection of an organic absorption feature at 3.4 micrometers on dwarf planet Ceres. This signature is characteristic of aliphatic organic matter and is mainly localized on a broad region of ~1000 square kilometers close to the ~50-kilometer Ernutet crater. The combined presence on Ceres of ammonia-bearing hydrated minerals, water ice, carbonates, salts, and organic material indicates a very complex chemical environment, suggesting favorable environments to prebiotic chemistry.

Distribution of phyllosilicates on the surface of Ceres.

The dwarf planet Ceres is known to host phyllosilicate minerals at its surface, but their distribution and origin have not previously been determined. We used the spectrometer onboard the Dawn spacecraft to map their spatial distribution on the basis of diagnostic absorption features in the visible and near-infrared spectral range (0.25 to 5.0 micrometers). We found that magnesium- and ammonium-bearing minerals are ubiquitous across the surface. Variations in the strength of the absorption features are spatially correlated and indicate considerable variability in the relative abundance of the phyllosilicates, although their composition is fairly uniform. These data, along with the distinctive spectral properties of Ceres relative to other asteroids and carbonaceous meteorites, indicate that the phyllosilicates were formed endogenously by a globally widespread and extensive alteration process.

Bright carbonate deposits as evidence of aqueous alteration on (1) Ceres.

The typically dark surface of the dwarf planet Ceres is punctuated by areas of much higher albedo, most prominently in the Occator crater. These small bright areas have been tentatively interpreted as containing a large amount of hydrated magnesium sulfate, in contrast to the average surface, which is a mixture of low-albedo materials and magnesium phyllosilicates, ammoniated phyllosilicates and carbonates. Here we report high spatial and spectral resolution near-infrared observations of the bright areas in the Occator crater on Ceres. Spectra of these bright areas are consistent with a large amount of sodium carbonate, constituting the most concentrated known extraterrestrial occurrence of carbonate on kilometre-wide scales in the Solar System. The carbonates are mixed with a dark component and small amounts of phyllosilicates, as well as ammonium carbonate or ammonium chloride. Some of these compounds have also been detected in the plume of Saturn's sixth-largest moon Enceladus. The compounds are endogenous and we propose that they are the solid residue of crystallization of brines and entrained altered solids that reached the surface from below. The heat source may have been transient (triggered by impact heating). Alternatively, internal temperatures may be above the eutectic temperature of subsurface brines, in which case fluids may exist at depth on Ceres today.

Ammoniated phyllosilicates with a likely outer Solar System origin on (1) Ceres.

Studies of the dwarf planet (1) Ceres using ground-based and orbiting telescopes have concluded that its closest meteoritic analogues are the volatile-rich CI and CM carbonaceous chondrites. Water in clay minerals, ammoniated phyllosilicates, or a mixture of Mg(OH)2 (brucite), Mg2CO3 and iron-rich serpentine have all been proposed to exist on the surface. In particular, brucite has been suggested from analysis of the mid-infrared spectrum of Ceres. But the lack of spectral data across telluric absorption bands in the wavelength region 2.5 to 2.9 micrometres--where the OH stretching vibration and the H2O bending overtone are found--has precluded definitive identifications. In addition, water vapour around Ceres has recently been reported, possibly originating from localized sources. Here we report spectra of Ceres from 0.4 to 5 micrometres acquired at distances from ~82,000 to 4,300 kilometres from the surface. Our measurements indicate widespread ammoniated phyllosilicates across the surface, but no detectable water ice. Ammonia, accreted either as organic matter or as ice, may have reacted with phyllosilicates on Ceres during differentiation. This suggests that material from the outer Solar System was incorporated into Ceres, either during its formation at great heliocentric distance or by incorporation of material transported into the main asteroid belt.

Olivine in an unexpected location on Vesta's surface.

Olivine is a major component of the mantle of differentiated bodies, including Earth. Howardite, eucrite and diogenite (HED) meteorites represent regolith, basaltic-crust, lower-crust and possibly ultramafic-mantle samples of asteroid Vesta, which is the lone surviving, large, differentiated, basaltic rocky protoplanet in the Solar System. Only a few of these meteorites, the orthopyroxene-rich diogenites, contain olivine, typically with a concentration of less than 25 per cent by volume. Olivine was tentatively identified on Vesta, on the basis of spectral and colour data, but other observations did not confirm its presence. Here we report that olivine is indeed present locally on Vesta's surface but that, unexpectedly, it has not been found within the deep, south-pole basins, which are thought to be excavated mantle rocks. Instead, it occurs as near-surface materials in the northern hemisphere. Unlike the meteorites, the olivine-rich (more than 50 per cent by volume) material is not associated with diogenite but seems to be mixed with howardite, the most common surface material. Olivine is exposed in crater walls and in ejecta scattered diffusely over a broad area. The size of the olivine exposures and the absence of associated diogenite favour a mantle source, but the exposures are located far from the deep impact basins. The amount and distribution of observed olivine-rich material suggest a complex evolutionary history for Vesta.

Spectroscopic characterization of mineralogy and its diversity across Vesta.

The mineralogy of Vesta, based on data obtained by the Dawn spacecraft's visible and infrared spectrometer, is consistent with howardite-eucrite-diogenite meteorites. There are considerable regional and local variations across the asteroid: Spectrally distinct regions include the south-polar Rheasilvia basin, which displays a higher diogenitic component, and equatorial regions, which show a higher eucritic component. The lithologic distribution indicates a deeper diogenitic crust, exposed after excavation by the impact that formed Rheasilvia, and an upper eucritic crust. Evidence for mineralogical stratigraphic layering is observed on crater walls and in ejecta. This is broadly consistent with magma-ocean models, but spectral variability highlights local variations, which suggests that the crust can be a complex assemblage of eucritic basalts and pyroxene cumulates. Overall, Vesta mineralogy indicates a complex magmatic evolution that led to a differentiated crust and mantle.

D184E mutation in aquaporin-4 gene impairs water permeability and links to deafness.

Aquaporins (AQPs) play a physiological role in several organs and tissues, and their alteration is associated with disorders of water regulation. The identification of molecular interactions, which are crucial in determining the rate of water flux through the channel, is of pivotal role for the discovery of molecules able to target those interactions and therefore to be used for pathologies ascribable to an altered AQP-dependent water balance. In the present study, a mutational screening of human aquaporin-4 (AQP4) gene was performed on subjects with variable degrees of hearing loss. One heterozygous missense mutation was identified in a Spanish sporadic case, leading to an Asp/Glu amino acid substitution at position 184 (D184E). A BLAST analysis revealed that the amino acid D184 is conserved across species, consistently with a crucial role in the structure/function of AQP4 water channels. The mutation induces a significant reduction in water permeability as measured by the Xenopus laevis oocytes swelling assay and by the use of mammalian cells by total internal reflection microscopy. By Western blot, immunofluorescence and 2D Blue Native/SDS-PAGE we show that the reduction in water permeability is not ascribable to a reduced expression of AQP4 mutant protein or to its incorrect plasma membrane targeting and aggregation into orthogonal arrays of particles. Molecular dynamics simulation provided a molecular explanation of the mechanism whereby the mutation induces a loss of function of the channel. Substituting glutamate for aspartate affects the mobility of the D loop, which acquires a higher propensity to equilibrate in a "closed conformation", thus affecting the rate of water flux. We speculate that this mutation, combined with other genetic defects or concurrently with certain environmental stimuli, could confer a higher susceptibility to deafness.

Serum and CSF N-acetyl aspartate levels differ in multiple sclerosis and neuromyelitis optica.

BACKGROUND: The identification of biomarkers able to improve the differential diagnosis between multiple sclerosis (MS) and neuromyelitis optica (NMO) is challenging because of a different prognosis and response to treatment. Growing evidence indicates that brain and CSF N-acetyl aspartate (NAA) concentration is a useful marker for characterising different phases of axonal pathology in demyelinating diseases, and preliminary studies suggest that increased serum NAA levels may be a telltale sign of acute neuronal damage or defective NAA metabolism in oligodendrocytes. OBJECTIVE: To evaluate whether serum and CSF NAA concentration differs in patients with MS and NMO. DESIGN: Observational, multicentre, prospective, cross sectional study. METHODS: Serum samples were collected from 48 relapsing-remitting MS, 32 NMO and 76 age matched healthy controls. Coeval CSF samples were available for all MS and for 8/32 NMO patients. NAA was measured in serum and CSF by liquid chromatography-mass spectrometry. RESULTS: MS patients showed higher serum and CSF NAA levels than NMO patients, and higher serum NAA levels than healthy controls (p<0.001). High serum NAA values, exceeding the 95th percentile of serum NAA values in healthy controls, were found in 100% of patients with MS and in no patient with NMO. No differences in serum NAA levels were found between NMO and healthy controls. In MS, serum and CSF NAA levels correlated with disability score. CONCLUSIONS: Determination of serum and CSF NAA levels may represent a suitable tool in the diagnostic laboratory workup to differentiate MS and NMO.

Higher order structure of aquaporin-4.

Unlike other mammalian AQPs, multiple tetramers of AQP4 associate in the plasma membrane to form peculiar structures called Orthogonal Arrays of Particles (OAPs), that are observable by freeze-fracture electron microscopy (FFEM). However, FFEM cannot give information about the composition of OAPs of different sizes, and due to its technical complexity is not easily applicable as a routine technique. Recently, we employed the 2D gel electrophoresis BN-SDS/PAGE that for the first time enabled the biochemical isolation of AQP4-OAPs from several tissues. We found that AQP4 protein is present in several higher-order complexes (membrane pools of supra-structures) which contain different ratios of M1/M23 isoforms corresponding to AQP4-OAPs of different size. In this paper, we illustrate in detail the potentiality of 2D BN/SDS-PAGE for analyzing AQP4 supra-structures, their relationship with the dystrophin glycoprotein complex and other membrane proteins, and their role as a specific target of Neuromyelitis Optica autoantibodies.

Effects of chronic treatment with statins and fenofibrate on rat skeletal muscle: a biochemical, histological and electrophysiological study.

BACKGROUND AND PURPOSE: Skeletal muscle injury by hypolipidemic drugs is not fully understood. An extensive analysis of the effect of chronic treatment with fluvastatin (5 mgkg(-1) and 20 mgkg(-1)), atorvastatin (10 mgkg(-1)) and fenofibrate (60 mgkg(-1)) on rat skeletal muscle was undertaken. EXPERIMENTAL APPROACH: Myoglobinemia as sign of muscle damage was measured by enzymatic assay. Histological and immunohistochemical techniques were used to estimate muscle integrity and the presence of aquaporin-4, a protein controlling water homeostasis. Electrophysiological evaluation of muscle Cl(-) conductance (gCl) and mechanical threshold (MT) for contraction, index of intracellular calcium homeostasis, was performed by the two-intracellular microelectrodes technique. KEY RESULTS: Fluvastatin (20 mgkg(-1)) increased myoglobinemia. The lower dose of fluvastatin did not modify myoglobinemia, but reduced urinary electrolytes, suggesting direct effects on renal function. Atorvastatin also increased myoglobinemia, with slight effects on urinary parameters. No treatment caused any histological damage to muscle or modification in the number of fibres expressing aquaporin-4. Either fluvastatin (at both doses) or atorvastatin reduced sarcolemma gCl and changed MT. Both statins produced slight effects on total cholesterol, suggesting that the observed modifications occur independently of HMGCoA-reductase inhibition. Fenofibrate increased myoglobinemia and decreased muscle gCl, whereas it did not change the MT, suggesting a different mechanism of action from the statins. CONCLUSIONS AND IMPLICATIONS: This study identifies muscle gCl and MT as early targets of drugs action that may contribute to milder symptoms of myotoxicity, such as muscle cramps, while the increase of myoglobinemia is a later phenomenon.

In vivo silencing of aquaporin-1 by RNA interference inhibits angiogenesis in the chick embryo chorioallantoic membrane assay.

Aquaporin-1 (AQP1) is a water channel protein mainly expressed in endothelial and epithelial cells of many tissues, including the vasculature where it serves to increase cell membrane water permeability. Previous studies in active multiple myeloma patients and in AQP1 KO mice indicated an involvement of AQP1 in physiological and tumor angiogenesis. To understand the physiological role of AQP1 in angiogenesis, we used a 21-nucleotide small interfering RNA duplexes (siRNA) to knockdown AQP1 in the chick embryo chorioallantoic membrane (CAM), a commonly used in vivo assay to study both angiogenic and angiostatic molecules. Chicken AQP1 sequence was identified and utilized to synthesize a siRNA directed to the AQP1 sequence. We then tested the efficiency of the siRNA in vitro, using an AQP1 transfected cell line. The level of AQP1 protein reduction obtained using siRNA was 98 % and 92 % after 1 and 2 day transfection respectively. RNA interference experiments were then performed in vivo by using the CAM assay. Results showed that after 4 days of treatment, AQP1 siRNA was able to strongly inhibit angiogenesis. This is the first study showing the in vivo use of RNA interference technique in the CAM assay. Our results strongly support the hypothesis that AQP1 could have a key role in physiological and pathological angiogenesis.

The role of aquaporin-4 in the blood-brain barrier development and integrity: studies in animal and cell culture models.

Aquaporin-4 (AQP4) is the major water channel expressed in brain perivascular astrocyte processes. Although the role of AQP4 in brain edema has been extensively investigated, little information exists regarding its functional role at the blood-brain barrier (BBB). The purpose of this work is to integrate previous and recent data regarding AQP4 expression during BBB formation and depending on BBB integrity, using several experimental models. Results from studies on the chick optic tectum, a well-established model of BBB development, and the effect of lipopolysaccharide on the BBB integrity and on perivascular AQP4 expression have been analyzed and discussed. Moreover, data on the BBB structure and AQP4 expression in murine models of Duchenne muscular dystrophy are reviewed. In particular, published results obtained from mdx(3cv) mice have been analyzed together with new data obtained from mdx mice in which all the dystrophin isoforms including DP71 are strongly reduced. Finally, the role of the endothelial component on AQP4 cellular expression and distribution has been investigated using rat primary astrocytes and brain capillary endothelial cell co-cultures as an in vitro model of BBB.

DNA adducts, benzo(a)pyrene monooxygenase activity, and lysosomal membrane stability in Mytilus galloprovincialis from different areas in Taranto coastal waters (Italy).

The aim of this study was to investigate the impact of environmental pollution at different stations along the Taranto coastline (Ionian Sea, Puglia, Italy) using several biomarkers of exposure and the effect on mussels, Mytilus galloprovincialis, collected in October 2001 and October 2002. Five sampling sites were compared with a "cleaner" reference site in the Aeronautics Area. In this study we also investigated the differences between adduct levels in gills and digestive gland. This Taranto area is the most significant industrial settlement on the Ionian Sea known to be contaminated by polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls, heavy metals, etc. Exposure to PAHs was evaluated by measuring DNA adduct levels and benzo(a)pyrene monooxygenase activity (B(a)PMO); DNA adducts were analyzed by 32P-postlabeling with nuclease P1 enhancement in both gills and digestive glands to evaluate differences between DNA adduct levels in the two tissues. B(a)PMO was assayed in the microsomal fraction of the digestive glands as a result of the high expression of P450-metabolizing enzymes in this tissue. Lysosomal membrane stability, a potential biomarker of anthropogenic stress, was also evaluated in the digestive glands of mussels, by measuring the latent activity of beta-N-acetylhexosaminidase. Induction of DNA adducts was evident in both tissues, although the results revealed large tissue differences in DNA adduct formation. In fact, gills showed higher DNA adduct levels than did digestive gland. No significant differences were found in DNA adduct levels over time, with both tissues providing similar results in both years. DNA adduct levels were correlated with B(a)PMO activity in digestive gland in both years (r = 0.60 in 2001; r = 0.73 in 2002). Increases were observed in B(a)PMO activity and DNA adduct levels at different stations; no statistical difference was observed in B(a)PMO activity over the two monitoring campaigns. The membrane labilization period in mussels from some stations was decreased in both years. No statistical differences were established in the membrane labilization times from 2001 to 2002. Our results suggest the existence of different sources and amounts of environmental contaminants at the stations investigated. The formation of DNA adducts confirms the existence of activation pathways in mussels and shows the importance of DNA adduct analysis in the gill tissue in addition to the more commonly used digestive gland; these results confirm the utility of lysosomal membrane stability as a biomarker of general stress. Overall, the integrated use of biomarkers of exposure and the effects of environmental contaminants on living marine organisms may help to better interpret the impact of pollutants in a marine coastal environment.

Altered blood-brain barrier development in dystrophic MDX mice.

In order to ascertain whether the alterations of the blood-brain barrier (BBB) seen in adult dystrophic mdx-mice [Glia 42 (2003) 235], a human model of Duchenne muscular dystrophy (DMD), are developmentally established and correlated with other dystrophin isoforms which are localized at the glial-vascular interface, we used immunocytochemistry to investigate the expression of dystrophin isoforms (Dp71) during BBB development in mdx fetuses and in adult mice. Parallelly, we used Western blot, immunocytochemistry and immunogold electron microscopy to analyze the expression of the zonula occludens (ZO-1), aquaporin-4 (AQP4) and glial fibrillary acidic (GFAP) proteins as endothelial and glial markers, and we evaluated the integrity of the mdx BBB by means of intravascular injection of horseradish peroxidase (HRP). The results show reduced dystrophin isoforms (Dp71) in the mdx mouse compared with the control, starting from early embryonic life. Endothelial ZO-1 expression was reduced, and the tight junctions were altered and unlabeled. AQP4 and GFAP glial proteins in mdx mice also showed modifications in developmental expression, the glial vascular processes being only lightly AQP4- and GFAP-labeled compared with the controls. Confocal microscopy and HRP assays confirmed the alteration in vessel glial investment, GFAP perivascular endfoot reactivity being strongly reduced and BBB permeability increasing. These results demonstrate that a reduction in dystrophin isoforms (Dp71) at glial endfeet leads to an altered development of the BBB, whose no-closure might contribute to the neurological dysfunctions associated with DMD.