A dehydrated space-weathered skin cloaking the hydrated interior of Ryugu

Without a protective atmosphere, space-exposed surfaces of airless Solar System bodies gradually experience an alteration in composition, structure and optical properties through a collective process called space weathering. The return of samples from near-Earth asteroid (162173) Ryugu by Hayabusa2 provides the first opportunity for laboratory study of space-weathering signatures on the most abundant type of inner solar system body: a C-type asteroid, composed of materials largely unchanged since the formation of the Solar System. Weathered Ryugu grains show areas of surface amorphization and partial melting of phyllosilicates, in which reduction from Fe3+ to Fe2+ and dehydration developed. Space weathering probably contributed to dehydration by dehydroxylation of Ryugu surface phyllosilicates that had already lost interlayer water molecules and to weakening of the 2.7 µm hydroxyl (–OH) band in reflectance spectra. For C-type asteroids in general, this indicates that a weak 2.7 µm band can signify space-weathering-induced surface dehydration, rather than bulk volatile loss

Short-term hemodialysis treatment in dogs and cats with total uretic obstruction

This study evaluated the single-pass system for the short-term dialysis treatment of dogs and cats with experimental renal failure. The hemodialyzer was equipped with a thin and highly permeable Cuprophan membrane. Four animals (two dogs and two cats) with total uretic obstruction were dialyzed twice in a one-week period. The vascular access by venipuncture of external jugular vein delivered more than 5 ml/min/kg/body weight of blood repeatedly, even for the cats. The evaluation of the effects of the blood flow, dialysate flow and ultrafiltration pressure revealed that the blood flow was the most important factor for effective dialysis. A 300 ml/min dialysate flow provided enough clearance of blood urea nitrogen and creatinine. The ultrafiltration pressure played an important role in ensuring that the fluid removal was constant. Laboratory studies revealed a 50.0% (range 42.0 to 59.3%) reduction of blood urea nitrogen, a 48.7% (range 42.5 to 58.7%) reduction of creatinine, and a 49.8% (range 34.3 to 66.2%) reduction of inorganic phosphate during the dialysis treatment. No dialysis disequilibrium syndrome was shown by the clinical signs. We conclude that this short-term dialysis using a single-pass system for small animals was sufficiently applicable to dogs and cats, and that the optimal duration of the dialysis was 2 hours