SHADOWS: a spectro-gonio radiometer for bidirectional reflectance studies of dark meteorites and terrestrial analogs: design, calibrations, and performances on challenging surfaces.

We have developed a new spectro-gonio radiometer, SHADOWS, to study in the laboratory the bidirectional reflectance distribution function of dark and precious samples. The instrument operates over a wide spectral range from the visible to the near-infrared (350-5000 nm) and is installed in a cold room to operate at a temperature as low as -20°C. The high flux monochromatic beam is focused on the sample, resulting in an illumination spot of about 5.2 mm in diameter. The reflected light is measured by two detectors with high sensitivity (down to 0.005% in reflectance) and absolute accuracy of 1%. The illumination and observations angles, including azimuth, can be varied over wide ranges. This paper presents the scientific and technical constraints of the spectro-gonio radiometer, its design and additional capabilities, as well as the performances and limitations of the instrument.

Radiative transfer model for contaminated rough slabs.

We present a semi-analytical model to simulate the bidirectional reflectance distribution function (BRDF) of a rough slab layer containing impurities. This model has been optimized for fast computation in order to analyze massive hyperspectral data by a Bayesian approach. We designed it for planetary surface ice studies but it could be used for other purposes. It estimates the bidirectional reflectance of a rough slab of material containing inclusions, overlaying an optically thick media (semi-infinite media or stratified media, for instance granular material). The inclusions are assumed to be close to spherical and constituted of any type of material other than the ice matrix. It can be any other type of ice, mineral, or even bubbles defined by their optical constants. We assume a low roughness and we consider the geometrical optics conditions. This model is thus applicable for inclusions larger than the considered wavelength. The scattering on the inclusions is assumed to be isotropic. This model has a fast computation implementation and thus is suitable for high-resolution hyperspectral data analysis.

Effect on blood lipids of two daily servings of Camembert cheese. An intervention trial in mildly hypercholesterolemic subjects.

As a concentrated source of saturated fat, cheese consumption is considered to be associated with increased cholesterolemia and generally forbidden in dietary guidelines for adults with hypercholesterolemia. The aim of this study was to evaluate the impact of saturated fatty acids on lipid parameters and blood pressure with regards to different types of dairy products: Camembert and full-fat yoghurt. One-hundred and fifty-nine moderate hypercholesterolemic subjects without treatment were instructed to consume two full-fat yoghurts (2 × 125 g) per day for 3 weeks (run-in period) and then for a further period of 5 weeks, either two full-fat yoghurts or two 30 g servings of Camembert cheese per day. We observed that over the 5-week daily consumption of two servings of Camembert cheese, blood pressure and serum lipids did not change in moderate hypercholesterolemic subjects. These results suggest that fermented cheese such as Camembert could be consumed daily without affecting serum lipids or blood pressure.

No signature of clear CO2 ice from the 'cryptic' regions in Mars' south seasonal polar cap.

The seasonal polar ice caps of Mars are composed mainly of CO2 ice. A region of low (< 30%) albedo has been observed within the south seasonal cap during early to mid-spring. The low temperature of this 'cryptic region' has been attributed to a clear slab of nearly pure CO2 ice, with the low albedo resulting from absorption by the underlying surface. Here we report near-infrared imaging spectroscopy of the south seasonal cap. The deep and broad CO2 absorption bands that are expected in the near-infrared with a thick transparent slab of CO2 ice are not observed. Models of the observed spectra indicate that the low albedo results from extensive dust contamination close to the surface of a CO2 ice layer, which could be linked to atmospheric circulation patterns. The strength of the CO2 absorption increases after mid-spring, so part of the dust is either carried away or buried more deeply in the ice layer during the CO2 ice sublimation process.

Large-scale cryovolcanic resurfacing on Pluto.

The New Horizons spacecraft returned images and compositional data showing that terrains on Pluto span a variety of ages, ranging from relatively ancient, heavily cratered areas to very young surfaces with few-to-no impact craters. One of the regions with very few impact craters is dominated by enormous rises with hummocky flanks. Similar features do not exist anywhere else in the imaged solar system. Here we analyze the geomorphology and composition of the features and conclude this region was resurfaced by cryovolcanic processes, of a type and scale so far unique to Pluto. Creation of this terrain requires multiple eruption sites and a large volume of material (>104 km3) to form what we propose are multiple, several-km-high domes, some of which merge to form more complex planforms. The existence of these massive features suggests Pluto's interior structure and evolution allows for either enhanced retention of heat or more heat overall than was anticipated before New Horizons, which permitted mobilization of water-ice-rich materials late in Pluto's history.

Dwarf planet (1) Ceres surface bluing due to high porosity resulting from sublimation.

The Dawn mission found that the dominant colour variation on the surface of dwarf planet Ceres is a change of the visible spectral slope, where fresh impact craters are surrounded by blue (negative spectral-sloped) ejecta. The origin of this colour variation is still a mystery. Here we investigate a scenario in which an impact mixes the phyllosilicates present on the surface of Ceres with the water ice just below. In our experiment, Ceres analogue material is suspended in liquid water to create intimately mixed ice particles, which are sublimated under conditions approximating those on Ceres. The sublimation residue has a highly porous, foam-like structure made of phyllosilicates that scattered light in similar blue fashion as the Ceres surface. Our experiment provides a mechanism for the blue colour of fresh craters that can naturally emerge from the Ceres environment.

Perennial water ice identified in the south polar cap of Mars.

The inventory of water and carbon dioxide reservoirs on Mars are important clues for understanding the geological, climatic and potentially exobiological evolution of the planet. From the early mapping observation of the permanent ice caps on the martian poles, the northern cap was believed to be mainly composed of water ice, whereas the southern cap was thought to be constituted of carbon dioxide ice. However, recent missions (NASA missions Mars Global Surveyor and Odyssey) have revealed surface structures, altimetry profiles, underlying buried hydrogen, and temperatures of the south polar regions that are thermodynamically consistent with a mixture of surface water ice and carbon dioxide. Here we present the first direct identification and mapping of both carbon dioxide and water ice in the martian high southern latitudes, at a resolution of 2 km, during the local summer, when the extent of the polar ice is at its minimum. We observe that this south polar cap contains perennial water ice in extended areas: as a small admixture to carbon dioxide in the bright regions; associated with dust, without carbon dioxide, at the edges of this bright cap; and, unexpectedly, in large areas tens of kilometres away from the bright cap.

Equatorial mountains on Pluto are covered by methane frosts resulting from a unique atmospheric process.

Pluto is covered by numerous deposits of methane, either diluted in nitrogen or as methane-rich ice. Within the dark equatorial region of Cthulhu, bright frost containing methane is observed coating crater rims and walls as well as mountain tops, providing spectacular resemblance to terrestrial snow-capped mountain chains. However, the origin of these deposits remained enigmatic. Here we report that they are composed of methane-rich ice. We use high-resolution numerical simulations of Pluto's climate to show that the processes forming them are likely to be completely different to those forming high-altitude snowpack on Earth. The methane deposits may not result from adiabatic cooling in upwardly moving air like on our planet, but from a circulation-induced enrichment of gaseous methane a few kilometres above Pluto's plains that favours methane condensation at mountain summits. This process could have shaped other methane reservoirs on Pluto and help explain the appearance of the bladed terrain of Tartarus Dorsa.

Ammonium salts are a reservoir of nitrogen on a cometary nucleus and possibly on some asteroids.

The measured nitrogen-to-carbon ratio in comets is lower than for the Sun, a discrepancy which could be alleviated if there is an unknown reservoir of nitrogen in comets. The nucleus of comet 67P/Churyumov-Gerasimenko exhibits an unidentified broad spectral reflectance feature around 3.2 micrometers, which is ubiquitous across its surface. On the basis of laboratory experiments, we attribute this absorption band to ammonium salts mixed with dust on the surface. The depth of the band indicates that semivolatile ammonium salts are a substantial reservoir of nitrogen in the comet, potentially dominating over refractory organic matter and more volatile species. Similar absorption features appear in the spectra of some asteroids, implying a compositional link between asteroids, comets, and the parent interstellar cloud.

Cost of care of colorectal cancers according to health care patterns and stage at diagnosis in France.

Little is known about the economic burden associated with colorectal cancer in France. The aim of this study was to evaluate the effects of age, stage at diagnosis, health care pattern and level of comorbidities on the mean cost of the management of colorectal cancers, using data from a population-based registry and the French health care system. We estimated the direct costs of medical care for 384 colorectal cancers diagnosed in 2004, using the three main databases of the National Health Insurance. The cost of management was defined as the sum of all health expenditures over the 12 months following the date of diagnosis. The mean cost for first-year management was 24,966 euro (SE 1,195 euro). There was no significant difference in overall costs in relation to sex, age, Charlson index score, cancer location or health care pattern. Costs increased significantly with cancer extension from 17,596 euro for stage I to 35,059 euro for stage IV. Hospitalisation charges represented the greatest economic burden (55.2%), followed by medical purchases (24.4%), outpatient care (17.8%) and transportation (2.5%). These results confirm the major economic burden of colorectal cancer and indicate that total costs depend mainly on the stage at diagnosis. By improving stage at diagnosis, mass screening could contribute to decreasing the cost of managing colorectal cancers.

Effects of N-acetylcysteine, oral glutathione (GSH) and a novel sublingual form of GSH on oxidative stress markers: A comparative crossover study.

Glutathione (GSH) is critical to fight against oxidative stress. Its very low bioavailability limits the interest of a supplementation. The purpose of this study was to compare the bioavailability, the effect on oxidative stress markers and the safety of a new sublingual form of GSH with two commonly used dietary supplements, N-acetylcysteine (NAC) and oral GSH. The study was a three-week randomized crossover trial. 20 Volunteers with metabolic syndrome were enrolled. GSH levels and several oxidative stress markers were determined at different times during each 21-days period. Compared to oral GSH group, an increase of total and reduced GSH levels in plasma and a higher GSH/GSSG ratio (p=0.003) was observed in sublingual GSH group. After 3 weeks of administration, there was a significant increase of vitamin E level in plasma only in sublingual GSH group (0.83 µmol/g; p=0.04). Our results demonstrate the superiority of a new sublingual form of GSH over the oral GSH form and NAC in terms of GSH supplementation.

Rat messenger RNA for the retinal pigment epithelium-specific protein RPE65 gradually accumulates in two weeks from late embryonic days.

The RPE65 protein appears late during the retinal development. To study the basis for this regulation, the rat RPE65 cDNA was sequenced and the mRNA subsequently quantitated at various stages by competitive RT-PCR. RPE65 mRNA was detected as early as E18 (36 copies/ng of whole eye total RNA). It gradually accumulates up to P12 (27000 copies/ng) at which point it reaches a steady state level. This increase is interrupted for 3 days (P2-P4) during which the levels of mRNA remain stable. This timing and rate of accumulation parallels that of rat and mouse opsin mRNA and suggests that common factors may control the activation of genes in photoreceptors and retinal pigment epithelium cells.

BIGH3 exon 14 mutations lead to intermediate type I/IIIA of lattice corneal dystrophies.

PURPOSE: To screen the BIGH3 gene in three unrelated families with lattice corneal dystrophy (LCD), two of which disclosed a particular phenotype. METHODS: Genomic DNA was extracted from peripheral leukocytes of the affected patients and their family members. The entire coding sequence of the BIGH3 gene was screened for mutations by means of transcript analysis on total RNA isolated from peripheral leukocytes by reverse transcription-polymerase chain reaction performed with primers designed for this study. Each mutation was confirmed at the genomic level, by using published primers. RESULTS: One family that had a typical form of LCD, had the described R124C mutation in the BIGH3 gene. Two families with atypical forms of LCD were negative for the previously known mutations of the gene. Direct sequencing of the BIGH3 mRNA in the latter two families allowed us to identify two mutations located in exon 14. They consist of a 9-bp insertion at position 18851886 and one missense mutation at position 1877 of the BIGH3 gene. Three new polymorphisms were also observed. CONCLUSIONS: Two mutations different from those linked to LCD have been found in clinically distinguishable forms of this disease, intermediate between LCDs types I and IIIA. The DNA segment comprising both alterations normally encodes for a highly conserved region of the fourth internal domain of the Betaig-h3 protein, suggesting that this region may be of functional and/or structural importance. The identification of new mutations by screening of the complete BIGH3 gene and the comparative analysis of the induced modifications in betaig-h3 protein should shed light in the understanding of the molecular mechanisms underlying LCDs resulting from mutations in the BIGH3 gene, and may help to explain their phenotypic heterogeneity.

Keratectasia induced by laser in situ keratomileusis in keratoconus.

PURPOSE: Corneal thinning disorders weaken the mechanical strength of affected corneas, suggesting that photorefractive procedures may be contraindicated in keratoconus. Few cases have been reported to confirm this hypothesis. METHODS: A 45-year-old man had two laser in situ keratomileusis (LASIK) procedures and one photorefractive keratectomy (PRK) performed on his left eye, and three LASIK procedures on his right eye. After these surgeries, a dramatic corneal ectasia and grade III haze occurred in both eyes, with a clinical diagnosis of keratoconus. The changes in his corneas were followed with videokeratography and slit-lamp microscopy. RESULTS: Preoperative videokeratograph of both eyes suggested keratoconus. After multiple refractive procedures, the best spectacle-corrected visual acuity was as low as 20/1200 bilaterally. Both eyes displayed dramatic corneal protrusion with corneal scarring. CONCLUSIONS: This case emphasizes the need for preoperative corneal thickness measurement and detailed analysis of videokeratographs. Thinning corneal disorders such as keratoconus, keratoconus suspects, or pellucid marginal degeneration are a contraindication for excimer laser ablative refractive procedures.

Keratographic analysis of a family with keratoconus in identical twins.

We screened family members of monozygotic twins with keratoconus to search for a corneal thinning disorder using clinical, videokeratographic, and pachymetric analyses. The parents had bilateral astigmatism of a symmetric bow-tie pattern with normal videokeratographic and pachymetric indices. The 8-year-old sister had slightly asymmetric astigmatism in both eyes with normal pachymetry values. No family member was suspected of a corneal thinning disorder. We discuss the mode of inheritance of keratoconus in this family.

Trauma after radial keratotomy and photorefractive keratectomy.

A 25-year-old man sustained bilateral ocular trauma from an explosion, which resulted in ocular injuries from the blast, mineral projections, and heat. Before the accident, the patient had eight-incision radial keratotomy in the left eye followed 1 week later by photorefractive keratectomy in the right eye. After the accident, the left cornea had a full-thickness rupture of four incisions; the fellow cornea had a full-thickness laceration from a mineral projection. Five months after the accident, the left eye had an uncorrected visual acuity of 20/25; the right eye did not achieve an acuity of 20/200 until 20 months after the accident.

Accuracy of IRAS GT interferometer and potential acuity meter prediction of visual acuity after phacoemulsification: prospective comparative study.

PURPOSE: To assess and compare the accuracy of 2 methods of predicting visual acuity after phacoemulsification. SETTING: Department of Ophthalmology, Montpellier, France. METHODS: This prospective study evaluated 47 eyes of 47 patients having uneventful phacoemulsification over a 1-month period. All the patients had mild to moderate cataract. Visual acuity recovery was predicted using the white-light IRAS GT interferometer on the 3- and 8-degree wide test area and the Guyton-Minkowski potential acuity meter (PAM). Best corrected visual acuity was evaluated 1 day before and 1 month after surgery. RESULTS: Both the interferometer and PAM underestimated the retinal visual capacity. Three-degree white-light interferometry gave significantly better mean predicted results than 8-degree interferometry and the PAM. There was no statistically significant disparity between predicted and postoperative results with 3-degree interferometry (1.04 +/- 0.57 logMAR; -0.09 +/- 0.27 decimal) (P =.0647) and a statistically significant disparity with 8-degree interferometry (0.89 +/- 0.59 logMAR; -0.13 +/- 0.27 decimal) and the PAM (0.66 +/- 0.62 logMAR; -0.22 +/- 0.24 decimal) (P =.0001). The predicted values were widely dispersed; the correlation indices were 0.38 with the PAM (P =.091), 0.39 with 3-degree interferometry (P =.001), and 0.49 with 8-degree interferometry (P =.0005). CONCLUSIONS: Three-degree white-light interferometry gave more accurate results than 8-degree interferometry and the PAM. The wide dispersion of results and unsatisfactory correlation indices show the tests are poor predictors of individual acuity. They should be used semiquantitatively and the results interpreted in relation to the clinical data. Qualitative methods may be useful in confirming or refuting visual recovery capacity ascertained by quantitative systems.

Clinical, histopathologic, and ultrastructural characteristics of BIGH3(TGFBI) amyloid corneal dystrophies are supportive of the existence of a new type of LCD: the LCDi.

PURPOSE: To assess the morphologic differences of three types of lattice corneal dystrophies (LCDs) from histologic, immunohistochemical, and ultrastructural studies. METHODS: Corneas from three patients, one LCD1, one His626Arg-LCD, and one LCD3A were processed for Congo red, betaig-h3(541-564) antibodies immunostaining, and electron transmission microscopy studies. Control tissues were submitted to identical analyses and consisted of one cornea from a patient not having LCD and one skin biopsy from the patient suffering from LCD1. RESULTS: The three corneas displayed birefringent congophilic deposits under polarized light, confirming their amyloid nature. The deposits differed regarding their shape and location in each of the corneas. A strong immunoreactivity for betaig-h3 was shown in the LCD1 and His626Arg-LCD deposits, which was faint for the LCD3A deposits. Ultrastructural analysis confirmed the dissimilarity of the deposits among the different types of LCD. No amyloid deposits were observed in the skin from the LCD1 patient, whereas immunostaining showed the presence of high amounts of betaig-h3. CONCLUSION: Our results show that betaig-h3 is involved in amyloid deposition in all the LCDs included in the study (LCD1, His626Arg-LCD, and LCD3A). These three forms of LCD, clinically different, were also distinguishable histologically, confirming that they belong to distinctive groups of LCDs. The absence of amyloid deposition in skin from the LCD1 patient supports cornea-specific amyloid formation. In light of the present clinical, histologic, and ultrastructural data, His626Arg and related LCDs constitute a separate group of LCD that could be considered as of intermediate type on clinical grounds.

Bicoronal incision for nasal bone grafting.

The use of bicoronal incisions has been sufficiently described in neurosurgery and craniofacial surgery including osteotomies and injuries. This approach provides excellent surgical access for nasal reconstruction with a very low rate of morbidity. A series of 11 patients, together with three case reports, illustrates the advantages and possible complications of this type of incision.

[Ocular trauma and caustic burns by air bags]. / Traumatisme oculaire et brûlure caustique par airbag.

We report two cases of ocular injuries caused by airbag inflation. These cases illustrate two main types of airbag-induced eye injuries: chemical and traumatic. In the first case, chemical keratitis was caused by the aerosol spray of alkaline particles produced by the airbag deployment system. In the second case, the high-speed deployment system caused mechanical injury to the anterior and posterior segments demonstrating the effect of the sudden deceleration when the individual hits the airbag. These two cases as well as others reported in the literature suggest that ocular injury should always be suspected because of the inherent traumatic effect of the airbag protection system.