摘要:
A cylindrical seizing element (3), made up of a fixed tubular part (32) comprising a cylindrical sector-shaped aperture (30) having a series of teeth (34) and of a movable inside part (31) also having a series of teeth (36) interposed between the first series of teeth, seizes the ends of turns of paper previously severed on a fresh reel of paper and brings the strip of paper unwinding from this fresh reel opposite a strip unwinding from an expiring reel. A splicing device comprising two rollers which are pressed against one another, one on each side of the two strips of paper, creates a splice through perforation of the two strips in an arrangement ensuring the strength of the splice. The method and apparatus are designed especially for integration in a single piece of equipment and for reliably joining two strips of paper intended to encircle cigarette filters.
摘要:
The trailing end (5) of a strip of paper (8) which was wound on a first reel (3) is immobilized by means of suction devices (16, 17, 18) relative to a counterplate (19). The trailing end is severed by means of a cutter (29), the rear portion being discarded by blowing. The leading end of the new strip of paper (11) is then positioned between a punch (20) and the counterplate, immobilized by means of a suction device (18), and joined to the trailing end by interpenetration, brought about by the punch, of the material of two superposed joining areas.
摘要:
The disclosed subject matter refers to hydroxyapatite and bioglass-based pellets of homogeneous size and spherical shape, whose interconnective porous structure, in the micrometer range, allows for an enhanced osteoconductivity and osteointegration, with specific application as a synthetic bone graft and to the respective production process. The production process is based on the pharmaceutical technology of extrusion and spheronization employing a porogenic agent and applying a sinterization stage in the presence of a vitreous liquid phase, which reverts on behalf of a higher reproducibility, superior yield and greater production capacity. Therefore, the disclosed subject matter is directed to the production of hydroxyapatite and bioglass-based pellets with applications in osteoregenerative medicine, particularly in the fields of orthopaedic surgery, maxillofacial surgery, dental surgery, implantology and as tissue engineering scaffolds
摘要:
The disclosed invention is based on hydroxyapatite, biocompatible glass and silicon, aiming to develop an improved bone substitute, which presents higher mechanical resistance, bioactivity and osteoregeneration, and susceptible of being used in several medical and surgical fields, with application in the treatment of bone disease caused by trauma or genetic factors, as osteoconductive support for cellular growth. The abovementioned bone substitute comprises hydroxyapatite, a biocompatible glass of the P2O5—CaO system in a percentage up to 10 wt % relatively to the hydroxyapatite weight, and a silicon source in a concentration up to 10 wt % relatively to hydroxyapatite and biocompatible glass weight. The preparation process of the disclosed bone substitute consists of liquid phase sintering of a homogeneous mixture of hydroxyapatite, biocompatible glass and silicon source preferentially within a temperature range of 1100-13500 C, which allows glass melting and fusion throughout hydroxyapatite structure leading to the occurrence of several ionic substitutions.
摘要:
The present invention provides a synthetic silicon-substituted apatite or hydroxyapatite which comprises 0.1% to 5% by weight of silicon. The silicon-substituted apatite or hydroxyapatite may be used as a synthetic bone material for use in bone substitution, implants, fillers and cements, coatings for metallic implants, and for making hydroxyapatite-polymer composites. The silicon-substituted apatite is prepared by reacting a calcium salt or calcium hydroxide with orthophosphoric acid or a salt of orthophosphoric acid in the presence of a silicon-containing compound, the molar ratio of calcium ions to phosphorous-containing ions being from 1:0.5 to 1:0.7 and the molar ratio of calcium ions to silicon-containing ions being at least 1:0.2, whereby a precipitate of a silicon-substituted apatite is formed. On heating and/or sintering the silicon-substituted apatite at a temperature of from 500° C. to 1400° C. part or substantially all of the silicon-substituted apatite transforms to silicon-substituted hydroxyapatite.
摘要:
A carriage (6) is moved so that the periphery of a roller (4) rests against the reel (3). The blade (14) of a knife (5) cuts the closing belt of the reel and a few of the outer turns of the strip. The roller is started up so that the scraps are drawn into a device (8) by suction, the free end of the strip also entering this device. The suction device pivots downward so that the free portion of the strip comes to rest upon a presentation block (54) which has meanwhile been advanced.