Bone Opaque

Melamine resins found a wider range of uses, including tableware (cups, saucers, plates), and in decorative and industrial laminates. One might think that melamine tableware never was likely to rival bone china in delicacy and appeal but it was attractive enough for the canteen, kitchen, or nursery, and less fragile even than delft or unglazed earthenware. The mouldings were available in a variety of opaque and translucent colours, and for a time enjoyed considerable popularity. 

Chalcedony after bone Petrified bone Usually red or brown, opaque, often shows cell structure (usually dinosaur bone)... 

Based on the clinical reports, 10-45% of patients who received the surgical implant with the bone cement need revision surgery mainly due to the cement fracture [36,37]. It is commonly accepted that the fatigue is the major mechanism for the fracture of bone cement [37,38]. The weak resistance of bone cement to the fatigue loading has been addressed to the low molecular weight of matrix, weak interfaces between filler materials and matrix, agglomeration of X-ray-opaque powder, bubbles, and so forth [38-40]. 

Since the X-ray-opaque filler (e.g., Zr02) is one of the basic components of bone cement, the physical properties of bone cement should be treated as a composite material of polymethyl methacrylate (PMMA) and fillers. The physical properties of composite materials depend on the matrices, fillers, and interfaces between them. The most desirable situation may be the combination of good properties of each component material. For this purpose, the role of interface is very important for an efficient stress transfer from the matrix to the fillers [41,42]. 

Figure 30.23 Fatigue life of PMMA bone cement with various kinds of plasma-treated X-ray opaque powder at 23 MPa maximum applied stresses under flexural loading.

Figure 30.25 depicts the correlation between the DPPH consumption and the fatigue life. Increasing trends of the fatigue life could be seen as the DPPH consumption increased regardless of the types of plasma treatments. The HMDSO plasma based treatment on the X-ray-opaque powder showed more pronounced trend in the effects of surface-bound peroxide on the fatigue properties of bone cement. 

The relation between the peroxide concentration on the X-ray-opaque powder and the gel time of bone cement could be seen in Figure 30.27, in which the time at maximal temperature was used instead of gel time or set time to avoid unnecessary error, since the temperature profiles seemed to have identical shape. As the DPPH consumption increased, the gel time decreased (i.e, faster polymerization) regardless of the types of plasma treatment, as seen in the relation between the fatigue properties and the peroxide concentration. The HMDSO plasma-based treatments showed a more pronounced effect than that by the methane plasma-based treatments. 

In the above section, effect of the interface between the X-ray-opaque filler and PMMA matrix has been investigated. In other words, no additional ingredient was added to the conventional PMMA bone cement recipe. In this section, our attention is focused on effect of the interface between milled carbon fiber and the bone cement matrix. Measurement of fatigue properties such as fatigue failure cycle deals with... 

Figure 30.27 Time to reach the maximum temperature during the polymerization of PMMA bone cement as a function of peroxide concentration on the plasma-treated X-ray opaque powder surfaces.

The comparison of (a) and (b) shows the effect of adding untreated milled carbon fibers, which is no improvement. The comparison of (a) and (c) shows the effect of the surface treatment of X-ray-opaque powders on fatigue cycles, which is a significant (nearly threefold) increase. The comparison of (c) and (d) shows the effect of adding untreated carbon fibers on bone cement with treated Zr02, which is an appreciable negative effect. The comparison of (d) and (e) shows the effect of the surface treatment of carbon fibers, which is a roughly twofold increase. 

The surface is a crucially important factor of biomaterial, and without an appropriate biocompatibility the biomaterial could not function. On the other hand, the bulk properties of materials are equally important in the use of biomaterials. An opaque material cannot be used in vision correction, and soft flexible materials cannot be used in bone reinforcement. The probability of finding a material that fulfills all requirements in physical and chemical bulk properties for a biomaterial application and whose surface properties are just right for a specific application is very close to zero, if not absolutely zero. From this point of view, all biomaterials should be surface treated to cope with the biocompatibility. However, if the surface treatment alters the bulk properties, it defeats the purpose. In this sense, tunable LCVD nanofilm coating that causes the minimal effect on the bulk material is the best tool available in the domain of biomaterials. 

Bone Cream Opaque Warm Black spots Black lines Rigid Chalky-blue... 

Addition of materials (for example antimicrobial drugs or radio-opaque contrast materials) to acrylic bone cement can cause mechanical weakness due to loss of homogeneity and greater water resorption. Antimicrobial drugs have been added to combat the problem of microbial adherence. However, this can lead to a considerable dead biofilm mass on the polymethylmethacrylate surface, promoting late infections by providing a surface attractive to other strains of bacteria (17). 

Moffett JW (1990) Microbially mediated cerium oxidation in seawater. Nature 345 421-423 Molleson Tl, Wilhams CT, Cressey G, Din VK (1998) Radiographically opaque bones from lead-lined coffins at Christ Church, Spitalfields, London—An extreme example of diagenesis. Bull Soc Geol France 169 425-432... 

Qualitative analysis X-ray absorption reveals the contours and location of high atomic weight elements in the presence of low atomic weight matrixes or holes in the interior of sohd samples (voids). Examples are bone locations in the human body, the contents of closed suitcases, old paintings hidden under new painting on a canvas, and voids in welded joints and opaque solid objects. 

Mannosidosis (an oligosaccharidosis). a-Mannosidase (EC 3.2.1.24). Accumulation of mannose-rich, glucosamine-containing oligosaccharides. Brain damage, bone abnormalities, opaque cornea and cataracts, hepatosplenomegaly. Skeletal involvement and facial features similar to Hurler s syndrome (below). 

Three volume rendering techniques (unshaded bone, shaded bone and shaded opaque bone) can help reveal both surface and internal detail and can be used for a better understanding of the volume rendered images ... 

The first image taken by Wilhelm Conrad Ront-gen, who discovered X rays in 1895, was of his wife s hand. It showed her opaque flesh, bones, and rings. 

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