Neptune Odyssey: A Flagship Concept for the Exploration of the Neptune–Triton System

The Neptune Odyssey mission concept is a Flagship-class orbiter and atmospheric probe to the Neptune-Triton system. This bold mission of exploration would orbit an ice-giant planet to study the planet, its rings, small satellites, space environment, and the planet-sized moon Triton. Triton is a captured dwarf planet from the Kuiper Belt, twin of Pluto, and likely ocean world. Odyssey addresses Neptune system-level science, with equal priorities placed on Neptune, its rings, moons, space environment, and Triton. Between Uranus and Neptune, the latter is unique in providing simultaneous access to both an ice giant and a Kuiper Belt dwarf planet. The spacecraft - in a class equivalent to the NASA/ESA/ASI Cassini spacecraft - would launch by 2031 on a Space Launch System or equivalent launch vehicle and utilize a Jupiter gravity assist for a 12 yr cruise to Neptune and a 4 yr prime orbital mission; alternatively a launch after 2031 would have a 16 yr direct-to-Neptune cruise phase. Our solution provides annual launch opportunities and allows for an easy upgrade to the shorter (12 yr) cruise. Odyssey would orbit Neptune retrograde (prograde with respect to Triton), using the moon's gravity to shape the orbital tour and allow coverage of Triton, Neptune, and the space environment. The atmospheric entry probe would descend in ~37 minutes to the 10 bar pressure level in Neptune's atmosphere just before Odyssey's orbit-insertion engine burn. Odyssey's mission would end by conducting a Cassini-like "Grand Finale,"passing inside the rings and ultimately taking a final great plunge into Neptune's atmosphere

A new apparatus for standardized rat kidney biopsy.

Survival biopsies are frequently applied in rat kidney disease models, but several drawbacks such as surgical kidney trauma, bleeding risk and variable loss of kidney tissue are still unsolved. Therefore, we developed an easy-to-use core biopsy instrument and evaluated whether two consecutive kidney biopsies within the same kidney can be carried out in a standardized manner. On day 0, 18 Lewis rats underwent a right nephrectomy and 9 of these rats a subsequent first biopsy of the left kidney (Bx group). 9 control rats had a sham biopsy of the left kidney (Ctrl group). On day 7, a second kidney biopsy/sham biopsy was performed. On day 42, all animals were sacrificed and their kidneys were removed for histology. Biopsy cylinders contained 57±28 glomeruli per transversal section, representing an adequate sample size. PAS staining showed that the biopsy depth was limited to the renal cortex whereas surgical tissue damage was limited to the area immediately adjacent to the taken biopsy cylinder. On day 42, the reduction of functional renal mass after two biopsies was only 5.2% and no differences of body weight, blood pressure, proteinuria, serum creatinine, glomerulosclerosis, interstitial fibrosis or number of ED-1 positive macrophages were found between both groups. In summary, our apparatus offers a safe method to perform repetitive kidney biopsies with minimal trauma and sufficient sample size and quality even in experimental disease models restricted to one single kidney

Technical drawing and operational principle of the new biopsy apparatus.

<p><b>A</b>: Longitudinal section. The sleight (in white) and the helve (in dark grey) interact by a slot and key linkage where the tongue of the sleight being located inside snaps into the circular grooves of the helve (arrowheads). <b>B and C</b>: Operational steps 1–3. The cutting filament around the circular blade forms the reference point for the stitch depth (*).</p

Comparison of the biopsy group with the control group on day 42^*.

<p>*Values are expressed as mean ±SD. Bx, biopsy group; Ctrl, control group; Body Wt, body weight; BP, blood pressure; Protein, proteinuria; SCr, serum creatinine; GS score, glomerulosclerosis score (see methods); IF score, interstitial fibrosis score (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0115368#s2" target="_blank">methods</a>); Glom ED-1, number of glomerular ED-1 positive macrophages/50 glomeruli; Inter ED-1, number of interstitial ED-1 positive macrophages/mm²; n.a., not applicable. Statistical significance was defined as <i>P</i><0.05.</p><p>Comparison of the biopsy group with the control group on day 42^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0115368#nt101" target="_blank">*</a>}.</p

Experimental set-up.

<p><b>Day 0</b>: Right nephrectomy in both groups. Subsequent biopsy of the upper pole of the residual kidney in the Bx group and sham biopsy of the residual kidney in the control group. <b>Day 7</b>: Biopsy of the lower kidney pole in the Bx group and second sham biopsy in the control group. <b>Day 42</b>: Animals were sacrificed and kidneys were removed for histology. Body weight, blood pressure, proteinuria and serum creatinine were measured before operations on day 0 and day 42 in both groups (*).</p