Efficacy and Safety of Percutaneous Sacroplasty for Painful Osteoporotic Sacral Insufficiency Fractures

PCT No. PCT/AU90/00258 Sec. 371 Date Dec. 9, 1991 Sec. 102(e) Date Dec. 9, 1991 PCT Filed Jun. 13, 1990 PCT Pub. No. WO90/15523 PCT Pub. Date Dec. 27, 1990.A solar structure, and more particularly a greenhouse, comprising a framework formed from frame members (20, 20a) and a flexible cover (26) having portions (28) of varying optical density along its length, and wound between a pair of opposed spooled 24 mounted on respective sides of the framework such that the cover is wound from one spool to the opposed spool. The cover is constrained to move over rollers (22) extending longitudinally of the framework, and the edges of the cover are received to move within slots formed in the edges of the frame members.