The nitrogen carrier in inner protoplanetary disks

The dominant reservoirs of elemental nitrogen in protoplanetary disks have not yet been observationally identified. Likely candidates are HCN, NH₃ and N₂. The relative abundances of these carriers determine the composition of planetesimals as a function of disk radius due to strong differences in their volatility. A significant sequestration of nitrogen in carriers less volatile than N₂ is likely required to deliver even small amounts of nitrogen to the Earth and potentially habitable exo-planets. While HCN has been detected in small amounts in inner disks (<10 au), so far only relatively insensitive upper limits on inner disk NH₃ have been obtained. We present new Gemini-TEXES high resolution spectroscopy of the 10.75 μm band of warm NH₃, and use 2-dimensional radiative transfer modeling to improve previous upper limits by an order of magnitude to [NH₃/Hnuc]<10−7 at 1 au. These NH₃ abundances are significantly lower than those typical for ices in circumstellar envelopes ([NH₃/Hnuc]∼3×10−6). We also consistently retrieve the inner disk HCN gas abundances using archival Spitzer spectra, and derive upper limits on the HCN ice abundance in protostellar envelopes using archival ground-based 4.7 μm spectroscopy ([HCNice]/[H₂Oice]<1.5−9\%). We identify the NH₃/HCN ratio as an indicator of chemical evolution in the disk, and use this ratio to suggest that inner disk nitrogen is efficiently converted from NH₃ to N₂, significantly increasing the volatility of nitrogen in planet-forming regions

<i>EPOXI</i>: comet 103P/Hartley 2 observations from a worldwide campaign

Earth- and space-based observations provide synergistic information for space mission encounters by providing data over longer timescales, at different wavelengths and using techniques that are impossible with an in situ flyby. We report here such observations in support of the EPOXI spacecraft flyby of comet 103P/Hartley 2. The nucleus is small and dark, and exhibited a very rapidly changing rotation period. Prior to the onset of activity, the period was ~16.4 hr. Starting in 2010 August the period changed from 16.6 hr to near 19 hr in December. With respect to dust composition, most volatiles and carbon and nitrogen isotope ratios, the comet is similar to other Jupiter-family comets. What is unusual is the dominance of CO2-driven activity near perihelion, which likely persists out to aphelion. Near perihelion the comet nucleus was surrounded by a large halo of water-ice grains that contributed significantly to the total water production

Protective Effects of Morroniside Isolated from Corni Fructus against Renal Damage in Streptozotocin-Induced Diabetic Rats

In our previous study, we reported the renoprotective effect of Hachimi-jio-gan, a Chinese traditional prescription consisting of eight medicinal plants, and also reported the effect of Corni Fructus (Cornus officinalis SIEB. et ZUCC.), a component of Hachimi-jio-gan, on diabetic nephropathy using diabetic rats. In this study, we investigated the effects of morroniside isolated from Corni Fructus on renal damage in streptozotocin-treated diabetic rats. Oral administration of morroniside at a dose of 20 or 100 mg/kg body weight/d for 20 d to diabetic rats resulted in significant decreases in increasing serum glucose and urinary protein levels. Moreover, the decreased levels of serum albumin and total protein in diabetic rats were significantly increased by morroniside administration at a dose of 100 mg/kg body weight/d. In addition, morroniside significantly reduced the elevated serum urea nitrogen level and showed a tendency to reduce creatinine clearance. Morroniside also significantly reduced the enhanced levels of serum glycosylated protein, and serum and renal thiobarbituric acid-reactive substances. Protein expressions related to the advanced glycation endproduct (AGE) level and actions, oxidative stress such as Nε-(carboxyethyl)lysine, as well as receptors for AGE and heme oxygenase-1 were increased in diabetic rats, but the levels were also significantly decreased by the administration of morroniside. This suggests that morroniside exhibits protective effects against diabetic renal damage by inhibiting hyperglycemia and oxidative stress. These results indicate that morroniside is one component partly responsible for the protective effects of Corni Fructus and Hachimi-jio-gan against diabetic renal damage