scholarly journals How to Build a Bone? - Hydroxyapatite or Posner`s Clusters as Bone Minerals

Open Ceramics ◽  
2021 ◽  
pp. 100092
Author(s):  
Iman Roohani ◽  
Soshan Cheong ◽  
Anna Wang
Keyword(s):  
Author(s):  
M. L. Zimny ◽  
A. C. Haller

During hibernation the ground squirrel is immobile, body temperature reduced and metabolism depressed. Hibernation has been shown to affect dental tissues varying degrees, although not much work has been done in this area. In limited studies, it has been shown that hibernation results in (1) mobilization of bone minerals; (2) deficient dentinogenesis and degeneration of alveolar bone; (3) presence of calculus and tears in the cementum; and (4) aggrevation of caries and pulpal and apical tooth abscesses. The purpose of this investigation was to study the effects of hibernation on dental tissues employing scanning electron microscopy (SEM) and related x-ray analyses.


Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2535
Author(s):  
Ji-Bong Choi ◽  
Yu-Kyoung Kim ◽  
Seon-Mi Byeon ◽  
Jung-Eun Park ◽  
Tae-Sung Bae ◽  
...  

In this study, a hydrogel using single and double crosslinking was prepared using GelMA, a natural polymer, and the effect was evaluated when the double crosslinked hydrogel and tannic acid were treated. The resulting hydrogel was subjected to physicochemical property evaluation, biocompatibility evaluation, and animal testing. The free radicals generated through APS/TEMED have a scaffold form with a porous structure in the hydrogel, and have a more stable structure through photo crosslinking. The double crosslinked hydrogel had improved mechanical strength and better results in cell compatibility tests than the single crosslinked group. Moreover, in the hydrogel transplanted into the femur of a rat, the double crosslinked group showed an osteoinductive response due to the attachment of bone minerals after 4 and 8 weeks, but the single crosslinked group did not show an osteoinductive response due to rapid degradation. Treatment with a high concentration of tannic acid showed significantly improved mechanical strength through H-bonding. However, cell adhesion and proliferation were limited compared to the untreated group due to the limitation of water absorption capacity, and no osteoinduction reaction was observed. As a result, it was confirmed that the treatment of high-concentration tannic acid significantly improved mechanical strength, but it was not a suitable method for improving bone induction due to the limitation of water absorption.


Geophysics ◽  
2018 ◽  
Vol 83 (1) ◽  
pp. H1-H11
Author(s):  
Blair B. Schneider ◽  
Georgios Tsoflias ◽  
Don W. Steeples ◽  
Rolfe Mandel ◽  
Jack Hofman

Ground-penetrating radar (GPR) is a powerful tool that is still being developed for archaeological investigations. We investigated the dielectric properties of mammoth bone and bone from modern bison, cow, deer, and elk as a proxy for applying GPR for detecting prehistoric animal remains. Sample dielectric properties (relative permittivity, loss factor, and loss-tangent values) were measured with an impedance analyzer over frequencies ranging from 10 MHz to 1 GHz. Bone-sample porosity, bulk density, water saturation, and volumetric water content of the specimens were also measured. The measured sample-relative permittivity values were then compared with modeled relative permittivity values using common dielectric-mixing models to determine which parameters control the best-fit predictions of relative permittivity of animal bone. We observe statistically significant dielectric-property differences among different animal fauna, as well as variation as a function of frequency. In addition, we determine that the relative permittivity values of 8–9 for similar minerals, such as apatite, are not suitable as a proxy for predicting animal bone properties. We estimate new relative permittivity values of 3–5 for dry animal bone minerals in the frequency range of 100–1000 MHz using these common dielectric-mixing models. We postulate that differences in bone microstructure contribute to dielectric-property variability.


Author(s):  
John Kalef-Ezra ◽  
Konstantinos Siamopoulos ◽  
Apostolos Karantanas ◽  
John Xatzikonstantinou ◽  
George Sferopoulos ◽  
...  

2014 ◽  
Vol 54 (9) ◽  
pp. 1394 ◽  
Author(s):  
V. Oehlschlaeger ◽  
M. Wilkens ◽  
B. Schroeder ◽  
S. Daenicke ◽  
G. Breves

The combination of 25-hydroxyvitamin D3 (25-OHD3) and a diet negative in dietary cation anion difference (DCAD) has recently been shown to have beneficial effects on peripartal calcium (Ca) homeostasis in dairy cows. To further elucidate the underlying mechanisms, it was the aim of the experiments to investigate the effects of 25-OHD3 in combination with DCAD values about –70 meq/kg DM on pre-duodenal and overall gastrointestinal Ca absorption. A group of six ruminally fistulated lactating cows equipped with a cannula in the proximal duodenum were assigned to three dietary treatments (Control diet, anionic salts, anionic salts +25-OHD3) of 5 weeks each. Urine and faeces were collected quantitatively and flow of duodenal contents was calculated by applying chromium oxide. Blood samples were taken at regular intervals. Treatment with anionic salts and 25-OHD3 resulted in an increased Ca net absorption from the total gastrointestinal tract, which was mainly due to respective increases in intestinal Ca absorption. Furthermore, anionic salts and 25-OHD3-treated animals had significantly higher plasma phosphate concentrations and lower plasma levels of CrossLaps and the overall net absorption of phosphorus was significantly higher in these animals. From these data, it can be concluded that anionic salts in combination with 25-OHD3 positively influence the overall net Ca and phosphorus absorption, which is obviously associated with a reduced mobilisation of bone minerals as indicated by decreases in plasma CrossLaps concentrations.


2010 ◽  
Vol 11 (10) ◽  
pp. 2545-2549 ◽  
Author(s):  
Abhijit Biswas ◽  
Ilker S. Bayer ◽  
He Zhao ◽  
Tao Wang ◽  
Fumiya Watanabe ◽  
...  

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