Progress with the Prime Focus Spectrograph for the Subaru Telescope: a massively multiplexed optical and near-infrared fiber spectrograph

The Prime Focus Spectrograph (PFS) is an optical/near-infrared multi-fiber spectrograph with 2394 science fibers, which are distributed in 1.3 degree diameter field of view at Subaru 8.2-meter telescope. The simultaneous wide wavelength coverage from 0.38 um to 1.26 um, with the resolving power of 3000, strengthens its ability to target three main survey programs: cosmology, Galactic archaeology, and galaxy/AGN evolution. A medium resolution mode with resolving power of 5000 for 0.71 um to 0.89 um also will be available by simply exchanging dispersers. PFS takes the role for the spectroscopic part of the Subaru Measurement of Images and Redshifts project, while Hyper Suprime-Cam works on the imaging part. To transform the telescope plus WFC focal ratio, a 3-mm thick broad-band coated glass-molded microlens is glued to each fiber tip. A higher transmission fiber is selected for the longest part of cable system, while one with a better FRD performance is selected for the fiber-positioner and fiber-slit components, given the more frequent fiber movements and tightly curved structure. Each Fiber positioner consists of two stages of piezo-electric rotary motors. Its engineering model has been produced and tested. Fiber positioning will be performed iteratively by taking an image of artificially back-illuminated fibers with the Metrology camera located in the Cassegrain container. The camera is carefully designed so that fiber position measurements are unaffected by small amounts of high special-frequency inaccuracies in WFC lens surface shapes. Target light carried through the fiber system reaches one of four identical fast-Schmidt spectrograph modules, each with three arms. Prototype VPH gratings have been optically tested. CCD production is complete, with standard fully-depleted CCDs for red arms and more-challenging thinner fully-depleted CCDs with blue-optimized coating for blue arms.Comment: 14 pages, 12 figures, submitted to "Ground-based and Airborne Instrumentation for Astronomy V, Suzanne K. Ramsay, Ian S. McLean, Hideki Takami, Editors, Proc. SPIE 9147 (2014)

Vascular homografts: Clinical results

The authors review the results of clinical experiences regarding arterial and venous homografts. For the treatment of mycotic aneurysms and infected prostheses, in situ repair with vascular homografts represents a valuable alternative to conventional surgical treatments. In fact the large caliber arterial homografts allow safe in situ reconstruction, decrease early and midterm mortality and reinfection rates; the best results are achieved in case of infected grafts, whereas the prognosis of vasculo-enteric fistula remains very poor. The small caliber arterial homografts also have demonstrated satisfactory results in term of patency although further experiences with longer follow-up are required. Vein homograft constitutes an alternative by-pass conduit for limb revascularisation in patient who lack adequate autogenous vein: although limb salvage rate is satisfactory long term patency rate is poor when compared with autogenous veins. Improvement of preservation methodics, pharmacological control of rejection and tissue engineering represent thefiture perspectives in this field

Percutaneous transluminal angioplasty in the treatment of stenosis of the renal artery in solitary functioning kidney

The authors report 2 cases of patients with single functioning kidney and severe hypertension caused by renal artery stenosis who were treated by percutaneous transluminal angioplasty (PTA). In one case an early and persistent improvement of renal function and a reduction of pressure values were observed. In the other patient, with preexistent severe functional damage, a progressive impairment of renal function required haemodialysis. On the basis of these results and of other reports in the literature, PTA is proposed as elective treatment of renal artery stenosis in patients with single functioning kidney