4,101 research outputs found
Development and characterisation of a decellularised bovine osteochondral biomaterial for cartilage repair.
It is proposed that an acellular natural osteochondral scaffold will provide a successful repair material for the early intervention treatment of cartilage lesions, to prevent or slow the progression of cartilage deterioration to osteoarthritis. Here, we investigated the efficacy of methods for the decellularisation of bovine osteochondral plugs. The plugs were subject to four freeze/thaw cycles followed by two cycles of washes in hypotonic solution and low concentration (0.1 % w/v) sodium dodecyl sulphate with protease inhibitors. Plugs were treated with nuclease (DNase and RNase) treatment followed by sterilization in peracetic acid. Full tissue decellularisation was achieved as confirmed by histological analysis and DNA quantification, however the resultant acellular matrix had reduced glycosaminoglycan content which led to an increased percent deformation of cartilage. Furthermore, the acellular scaffold was not reproducibly biocompatible. Additional terminal washes were included in the process to improve biocompatibility, however, this led to visible structural damage to the cartilage. This damage was found to be minimised by reducing the cut edge to cartilage area ratio through decellularisation of larger cuts of osteochondral tissue
NGC 300 X-1 is a Wolf-Rayet/Black-Hole binary
We present VLT/FORS2 time-series spectroscopy of the Wolf-Rayet star #41 in
the Sculptor group galaxy NGC 300. We confirm a physical association with NGC
300 X-1, since radial velocity variations of the HeII 4686 line indicate an
orbital period of 32.3 +/- 0.2 hr which agrees at the 2 sigma level with the
X-ray period from Carpano et al. We measure a radial velocity semi-amplitude of
267 +/- 8 km/s, from which a mass function of 2.6 +/- 0.3 Msun is obtained. A
revised spectroscopic mass for the WN-type companion of 26+7-5 Msun yields a
black hole mass of 20 +/- 4 Msun for a preferred inclination of 60-75 deg. If
the WR star provides half of the measured visual continuum flux, a reduced WR
(black hole) mass of 15 +4 -2.5 Msun (14.5 +3 -2.5 Msun) would be inferred. As
such, #41/NGC 300 X-1 represents only the second extragalactic Wolf-Rayet plus
black-hole binary system, after IC 10 X-1. In addition, the compact object
responsible for NGC 300 X-1 is the second highest stellar-mass black hole known
to date, exceeded only by IC 10 X-1.Comment: 5 pages, 6 figures, MNRAS Letters in press. Images and animations
available from http://www.eso.org/public/news/eso1004/ at 11am GMT on 27 Jan
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