ISSN:0021-9304    

DOI:10.1002/jbm.820090502

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractPrevious work has shown that needles of γ2crystals form when mercury is plated on the surface of an Ag3Sn specimen. In the present study, the growth kinetics of γ2needles were investigated from room temperature to 50°C for varying amounts of plated mercury. Straight‐line relationships between crystal length and the square root of the time of growth showed that the growth rate is diffusion controlled. The growth rate increased with temperature up to 40°C but decreased at higher temperatures. Further, as the temperature was increased, fewer γ2crystals formed and their growth length decreased. This demonstrates that a number of competing factors are involved in the growth process at high temper

ISSN:0021-9304    

DOI:10.1002/jbm.820090503

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractAt present, the smallest needle commonly available is about 130 μm in diameter in combination with a suture of about 25 μm in diameter. Marked reductions in size, particularly of the needle, are advantageous for microvascular surgery.A needle of about 70 μm in diameter, welded to a suture of about 18 μm diameter, has been developed. In initial tests, it has performed satisfactorily in the repair of the carotid artery of the white rat. It is shown that the basic properties of materials severely limit further reductions in the size of needles and sutu

ISSN:0021-9304    

DOI:10.1002/jbm.820090504

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractThe adhesion of radio‐labeled chick embryo muscle cells to the surfaces of radiation grafted hydrogels and other polymeric materials was measuredin vitro. The degree of adhesion was determined by measuring the percentage of cells which remained adherent to the surfaces after 180 min of contact time (plating efficiency). Plating efficiency was found to vary between 2 and 94% depending on the nature of the surface. Preadsorption of albumin, γ‐globulin or fibrinogen markedly affected subsequent adhesion of cells. Radiation grafted poly(2‐hydroxyethyl methacrylate) and poly(N‐vinyl‐2‐pyrrolidone) hydrogels on silicone rubber demonstrated exceptionally low adhesiveness in this assay. The potential for using this cell adhesion assay as a general screening test for biomaterials

ISSN:0021-9304    

DOI:10.1002/jbm.820090505

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractSlow crack growth in Perspex acrylic sheet (PMMA) and Simplex acrylic bone cement in air and water has been studied from a fracture mechanics viewpoint. It has been found that the crack velocity,V, for each material depends upon the intensification of stress at the tip of the crack. Experimental measurements have been made ofVas a function of the stress intensity factor,K, at the crack tip, and a derivedV,Krelationship has been used to predict the times‐to‐failure of components made from PMMA and Simplex cement. Direct measurements of time‐to‐failure for PMMA have shown that the predicted values give a conservative estimate of the structural lifetime of the m

ISSN:0021-9304    

DOI:10.1002/jbm.820090506

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractCeramic pelletes (in Al2O392% and in calcium aluminate) implanted into the muscles of rabbits for varying periods of time, and samples of similar material, not implanted but mixed with organic substances, have been analyzed by means of thermal differential analysis (TDA).Which hydrated calcium aluminates are formed from implants after contact with the tissure fluid, has been established.It has also been ascertained that the ceramic implants absorb organic substances from the tissue fluid, which, from a first evaluation, seem to be composed of simple molecules.The results of this initial inquiry have provided positive indications of the utility of TDA to assist in elucidating the phenomena that occur between implant and tissue.

ISSN:0021-9304    

DOI:10.1002/jbm.820090507

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractDogs were dialyzed with collagen and cuprophane membranes, human renal failure patients were dialyzed with cuprophane membranes, and samples of the membranes were observed by scanning electron microscopy at different time periods. Fixation was done in glutaraldehyde and cacodylate buffer, and samples were dried at the critical point. All cellular elements were well preserved and appeared viable. Cuprophane adsorbed platelets almost selectively in dog dialyses, whereas collagen adsorbed a smaller number and more heterogeneous group of cells. In contrast to these findings, when cuprophane was used in clinical dialyses, the cell population was predominantly polymorphonuclear leukocytes.

ISSN:0021-9304    

DOI:10.1002/jbm.820090508

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractA case of a failed total hip replacement consisting of a Vitallium hip socket and a stainless steel femoral head prosthesis is presented. The mixed‐metal combination and inadequate design resulted in severe abrasive wear and fretting corrosion of the bearing surface, and the accumulation of stainless steel wear debris and corrosion products in the periarticular tissues was extensive.The tissue response was primarily fibrotic scarring with severe histiocytic and mild foreign body giant cell reaction. Despite the massive accumulation of wear debris and corrosion products, however, there was minimal chronic inflammation and no acute inflammatio

ISSN:0021-9304    

DOI:10.1002/jbm.820090509

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractBecause fluorocarbons can dissolve relatively large quantities of oxygen and carbon dioxide, there is considerable interest in utilizing them to develop new methods of extracorporael circulation, artificial red blood cells, and liquid breathing techniques. A method for the assay of fluorocarbon in blood is presented. The fluorocarbon is extracted from the blood with toluene, and fluoride is released from the fluorocarbon in the toluene extract by reaction with sodium biphenyl. The inorganic fluoride is then extracted with aqueous sodium acetate, the pH of the extract is adjusted, and the activity of the fluoride ion is read with a fluoride‐specific ion electrode. The assay was effective for fluorocarbon concentrations in the range 1 to 30 pp

ISSN:0021-9304    

DOI:10.1002/jbm.820090510

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractSurface modification of cellulose acetate dialysis membranes was carried out by60Co radiation induced graft copolymerization of the hydrogel, hydroxyethyl methacrylate (HEMA). The degree of grafting was controlled by varying the HEMA monomer concentration in the grafting solution and the radiation dose. A continuous flow platelet adhesion test was designed which allows testing under conditions more closely approximating hemodialysis than other small scalein vitrotests. Platelet adhesion on treated membranes fell substantially with increasing surface HEMA concentration. The presence of HEMA on the membrane surface did not affect the membrane activated clotting times significantly.

ISSN:0021-9304    

DOI:10.1002/jbm.820090511

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY