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Biomolecules and Tissue Properties
Published in Joseph W. Freeman, Debabrata Banerjee, Building Tissues, 2018
Joseph W. Freeman, Debabrata Banerjee
There are other types of calcium phosphate in bone, not just HAP, although it is the main type. Other types of calcium phosphate present include amorphous calcium phosphate, tricalcium phosphate, brushite, and octacalcium phosphate. There are different theories about the formation of mineral, specifically HAP in bone. It is theorized that amorphous calcium phosphate is composed of mainly tricalcium phosphate. The Ca2+ and PO4− ions begin to aggregate in a simple manner and then over time form a more complex, crystalline structure11,12 (Figure 3.22). As time passes, the amorphous material would be converted into a crystalline mineral. This process would be hindered by the presence of inhibitors such as adenosine triphosphate (ATP), pyrophosphate, diphosphate, and some phospholipids. Another theory suggests that other types of calcium phosphate are produced as precursors, which are then hydrolyzed into HAP. It has been proposed that other calcium phosphates (such as octacalcium phosphate or brushite) are initially produced and then converted into HAP (Figure 3.22). Tricalcium phosphate, Ca3(PO4)2, (also known as calcium orthophosphate, tertiary calcium phosphate, and tribasic calcium phosphate) is one of the main combustion products of bone (bone ash). Another common form of calcium phosphate is brushite (also known as Dicalcium Phosphate Dihydrate [DCPD]). It is a hydrated calcium phosphate with the composition CaHPO4·2H2O. It is usually the calcium phosphate source of kidney stones.
Whiteware and Glazes
Published in Debasish Sarkar, Ceramic Processing, 2019
On the contrary, bone china bodies with their distinct translucency have a different composition with an appreciable amount of bone ash. Bone ash is a raw material typically consisting of tricalcium phosphate [Ca3(PO4)2] and small impurities. The composition of bone china bodies varies with china clay ~25%–30%, bone ash ~35%–45%, and feldspar ~25%–30%. Bisque firing of bone china bodies is generally performed at ~1225°C–1300°C. Since bone china bodies suffer from high shrinkage, extra precaution must be taken during the drying and firing cycles. Bone ash that contains P2O5 has a highly fluxing nature, increasing the fluidity of the melt and providing a short firing range.
Case Studies
Published in Caroline O’Donnell, Dillon Pranger, The Architecture of Waste, 2020
Caroline O’Donnell, Dillon Pranger
Serving as the structural system for the body when it is alive, the manufacturing of posthumous human bones into load-bearing architectural elements is fitting. In fact, ash from animal bones has long been used as an ingredient in ceramics, specifically, and as the name suggests, in fine bone china, which is composed of nearly 50% animal bone ash.4 It is, in fact, the bone ash that gives these ceramics their distinctive translucent characteristic.
Predicting the effective compressive modulus of human cancellous bone using the convolutional neural network method
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2023
Yongtao Lu, Zhuoyue Yang, Hanxing Zhu, Chengwei Wu
The effective compressive modulus of the cancellous bone samples calculated from the FE models was taken as the ground truth and used to train the CNN model constructed in the present study. To obtain the effective compressive modulus, the heterogeneous FE model of human cancellous bone was created using the method previously developed (Lu et al. 2019). Briefly, the grayscale image datasets of cancellous bone were first smoothed using a Gaussian filter (sigma = 1.2, support = 2.0) to reduce the influence of image noise and then each image voxel was converted into a two-dimensional (2D) 4-node plane stress element (PLANE182) (ANSYS, Inc. 1994). In the generated FE mesh model, the heterogeneous material model was defined by converting the image grayscale values to the corresponding Young's moduli (Figure 2). Image grayscale values were first converted into the vBMD values based on the linear calibration equation provided by the HR-pQCT scanner. The vBMD values were then converted into the bone ash density using the relationship reported in the literature (Knowles et al. 2016), that is, ( is the bone ash density, unit in mg/cm3; is the HA-equivalent vBMD, unit in mg/cm3). Young's modulus of each bone elements was then calculated from the bone ash density using the following exponential density–modulus relationship (Knowles et al. 2016):
Catalysts used in biodiesel production: a review
Published in Biofuels, 2021
In this study, metal oxides have been studied as heterogeneous alkaline catalysts. A number of metal oxides studied in the articles cited here are as follows: calcium oxide (CaO), magnesium oxide (MgO), (CaO/ZnO), (Li/CaO), mixed metal oxides and hydrotalcite [52,53], as shown in Table 5. Also, mixed metal oxides such as Mg/Al and Mg/Zr have been studied. In fact, they have performed well in the transesterification process [54,55]. Heterogeneous alkaline catalysts can be obtained from various sources of waste such as bone, ash and shell. These sources have high potentials as catalysts for the production of biodiesel [51]. Heterogeneous alkaline catalysts are used to overcome the limitations of homogeneous alkaline catalysts, including soap formation. The latter limitation prevents the separation of the glycerol layer from the methyl ester layer [40,56]. Furthermore, the alkaline catalysts can be easily separated and reused, and because they have low solubility and possibly are used in the reaction, their active sites are destroyed, but they can be reconstructed by simple methods [57]. However, one of the disadvantages of heterogeneous alkaline catalysts is their tendency to absorb moisture during storage [47].
Fluoride and human health: Systematic appraisal of sources, exposures, metabolism, and toxicity
Published in Critical Reviews in Environmental Science and Technology, 2020
Humayun Kabir, Ashok Kumar Gupta, Subhasish Tripathy
In animal bodies, bone may be considered a natural sink for F−. Long-term exposure to excessive F− leads to skeletal fluorosis, whose severity increases with the level of F− and duration of exposure (Guissouma, Hakami, Al-Rajab, & Tarhouni, 2017; Spencer, Osis, & Wiatrowski, 1975). Skeletal fluorosis is characterized by extra growth of bone, resulting in increased bone mass and density along with enlarged joints, which may appear in various parts of the skeleton. This type of fluorosis is considered the most relevant evidence of long-term F− exposure (WHO, 2002). The deposition of F− with advancing age leads to decreased overall bone ash content, thereby resulting in increased bone porosity (Stein & Granik, 1980). Exposure to F− increases bone volume and trabecular thickness without increasing trabecular connectivity. Despite increasing bone mass, a lack of trabecular bone connectivity decreases bone quality (Aaron, De Vernejoul, & Kanis, 1991).