scholarly journals Bone Organic-Inorganic Phase Ratio Is a Fundamental Determinant of Bone Material Quality

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Yunhua Luo ◽  
Ogheneriobororue Amromanoh
Keyword(s):  
Mechanical Properties ◽  
Peak Stress ◽  
Bone Diseases ◽  
Phase Ratio ◽  
Statistical Characteristics ◽  
Mineral Density ◽  
Bone Material ◽  
Material Quality ◽  
Manufacturing Method ◽  
Optimal Ratio

Background. Bone mineral density is widely used by clinicians for screening osteoporosis and assessing bone strength. However, its effectiveness has been reported unsatisfactory. In this study, it is demonstrated that bone organic-inorganic phase ratio is a fundamental determinant of bone material quality measured by stiffness, strength, and toughness. Methods and Results. Two-hundred standard bone specimens were fabricated from bovine legs, with a specialized manufacturing method that was designed to reduce the effect of bone anisotropy. Bone mechanical properties of the specimens, including Young’s modulus, yield stress, peak stress, and energy-to-failure, were measured by mechanical testing. Organic and inorganic mass contents of the specimens were then determined by bone ashing. Bone density and organic-inorganic phase ratio in the specimens were calculated. Statistical methods were applied to study relationships between the measured mechanical properties and the organic-inorganic phase ratios. Statistical characteristics of organic-inorganic phase ratios in the specimens with top material quality were investigated. Bone organic-inorganic phase ratio had strong Spearman correlation with bone material properties. Bone specimens that had the highest material quality had a very narrow scope of organic-inorganic phase ratio, which could be considered as the “optimal” ratio among the tested specimens. Conclusion. Bone organic-inorganic phase ratio is a fundamental determinant of bone material quality. There may exist an “optimal” ratio for the bone to achieve top material quality. Deviation from the “optimal” ratio is probably the fundamental cause of various bone diseases. This study suggests that bone organic-inorganic phase ratio should be considered in clinical assessment of fracture risk.

scholarly journals Ibandronate Suppresses Changes in Apatite Orientation and Young's Modulus Caused by Estrogen Deficiency in Rat Vertebrae

2022 ◽  
Author(s):  
Takuya Ishimoto ◽  
Mitsuru Saito ◽  
Ryosuke Ozasa ◽  
Yoshihiro Matsumoto ◽  
Takayoshi Nakano
Keyword(s):  
Bone Loss ◽  
Bone Mass ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Estrogen Deficiency ◽  
Dependent Manner ◽  
Mineral Density ◽  
Bone Material ◽  
Material Quality ◽  
Mechanical Integrity

AbstractBone material quality is important for evaluating the mechanical integrity of diseased and/or medically treated bones. However, compared to the knowledge accumulated regarding changes in bone mass, our understanding of the quality of bone material is lacking. In this study, we clarified the changes in bone material quality mainly characterized by the preferential orientation of the apatite c-axis associated with estrogen deficiency-induced osteoporosis, and their prevention using ibandronate (IBN), a nitrogen-containing bisphosphonate. IBN effectively prevented bone loss and degradation of whole bone strength in a dose-dependent manner. The estrogen-deficient condition abnormally increased the degree of apatite orientation along the craniocaudal axis in which principal stress is applied; IBN at higher doses played a role in maintaining the normal orientation of apatite but not at lower doses. The bone size-independent Young's modulus along the craniocaudal axis of the anterior cortical shell of the vertebra showed a significant and positive correlation with apatite orientation; therefore, the craniocaudal Young’s modulus abnormally increased under estrogen-deficient conditions, despite a significant decrease in volumetric bone mineral density. However, the abnormal increase in craniocaudal Young's modulus did not compensate for the degradation of whole bone mechanical properties due to the bone loss. In conclusion, it was clarified that changes in the material quality, which are hidden in bone mass evaluation, occur with estrogen deficiency-induced osteoporosis and IBN treatment. Here, IBN was shown to be a beneficial drug that suppresses abnormal changes in bone mechanical integrity caused by estrogen deficiency at both the whole bone and material levels.

Calcium and Vitamin D Supplementation. Myths and Realities with Regard to Cardiovascular Risk

2019 ◽  
Vol 17 (6) ◽  
pp. 610-617 ◽  
Author(s):  
Giovanna Muscogiuri ◽  
Luigi Barrea ◽  
Barbara Altieri ◽  
Carolina Di Somma ◽  
Harjit pal Bhattoa ◽  
...  
Keyword(s):  
Vitamin D ◽  
Side Effects ◽  
Secondary Hyperparathyroidism ◽  
Calcium Supplementation ◽  
Physiological Role ◽  
Bone Diseases ◽  
Current Evidence ◽  
Bone Homeostasis ◽  
Mineral Density ◽  
Muscle Health

Vitamin D and calcium are considered crucial for the treatment of bone diseases. Both vitamin D and calcium contribute to bone homeostasis but also preserve muscle health by reducing the risk of falls and fractures. Low vitamin D concentrations result in secondary hyperparathyroidism and contribute to bone loss, although the development of secondary hyperparathyroidism varies, even in patients with severe vitamin D deficiency. Findings from observational studies have shown controversial results regarding the association between bone mineral density and vitamin D/calcium status, thus sparking a debate regarding optimum concentrations of 25-hydroxyvitamin D and calcium for the best possible skeletal health. Although most of the intervention studies reported a positive effect of supplementation with calcium and vitamin D on bone in patients with osteoporosis, this therapeutic approach has been a matter of debate regarding potential side effects on the cardiovascular (CV) system. Thus, the aim of this review is to consider the current evidence on the physiological role of vitamin D and calcium on bone and muscle health. Moreover, we provide an overview on observational and interventional studies that investigate the effect of vitamin D and calcium supplementation on bone health, also taking into account the possible CV side-effects. We also provide molecular insights on the effect of calcium plus vitamin D on the CV system.

scholarly journals Intra-Bone Marrow Administration of Mesenchymal Stem/Stromal Cells Is a Promising Approach for Treating Osteoporosis

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Hideki Agata ◽  
Yoshinori Sumita ◽  
Tatsuro Hidaka ◽  
Mayumi Iwatake ◽  
Hideaki Kagami ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Bone Mineral Content ◽  
Bone Mineral ◽  
Intravenous Administration ◽  
Stromal Cells ◽  
Mineral Content ◽  
Bone Diseases ◽  
Research Progress ◽  
Bone Thickness ◽  
Mineral Density

Mesenchymal stem/stromal cells (MSCs) are known to be useful for treating local bone diseases. However, it is not known if MSCs are effective for treating systemic bone diseases, as the risk for mortality following intravenous MSC administration has hindered research progress. In this study, we compared the safety and efficacy of intra-bone marrow and intravenous administration of MSCs for the treatment of ovariectomy- (OVX-) induced osteoporosis. Cells capable of forming bone were isolated from the murine compact bones and expanded in culture. Relatively pure MSCs possessing increased potential for cell proliferation, osteogenic differentiation, and inhibition of osteoclastogenesis were obtained by magnetic-activated cell sorting with the anti-Sca-1 antibody. Sca-1-sorted MSCs were administered to OVX mice, which were sacrificed 1 month later. We observed that 22% of the mice died after intravenous administration, whereas none of the mice died after intra-bone marrow administration. With respect to efficacy, intravenous administration improved bone mineral density (BMD) by increasing bone mineral content without affecting bone thickness, whereas intra-bone marrow administration improved BMD by increasing both bone mineral content and bone thickness. These results indicate that intra-bone marrow administration of pure MSCs is a safer and more effective approach for treating osteoporosis.

scholarly journals Comparison of Mechanical Properties of PMMA Disks for Digitally Designed Dentures

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1745
Author(s):  
Tamaki Hada ◽  
Manabu Kanazawa ◽  
Maiko Iwaki ◽  
Awutsadaporn Katheng ◽  
Shunsuke Minakuchi
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Water Sorption ◽  
Water Solubility ◽  
Flexural Modulus ◽  
Manufacturing Method ◽  
Heat Curing ◽  
Significant Difference ◽  
Cad Cam ◽  
Curing Method

In this study, the physical properties of a custom block manufactured using a self-polymerizing resin (Custom-block), the commercially available CAD/CAM PMMA disk (PMMA-disk), and a heat-polymerizing resin (Conventional PMMA) were evaluated via three different tests. The Custom-block was polymerized by pouring the self-polymerizing resin into a special tray, and Conventional PMMA was polymerized with a heat-curing method, according to the manufacturer’s recommended procedure. The specimens of each group were subjected to three-point bending, water sorption and solubility, and staining tests. The results showed that the materials met the requirements of the ISO standards in all tests, except for the staining tests. The highest flexural strength was exhibited by the PMMA-disk, followed by the Custom-block and the Conventional PMMA, and a significant difference was observed in the flexural strengths of all the materials (p < 0.001). The Custom-block showed a significantly higher flexural modulus and water solubility. The water sorption and discoloration of the Custom-block were significantly higher than those of the PMMA-disk, but not significantly different from those of the Conventional PMMA. In conclusion, the mechanical properties of the three materials differed depending on the manufacturing method, which considerably affected their flexural strength, flexural modulus, water sorption and solubility, and discoloration.

scholarly journals Kalkitoxin Reduces Osteoclast Formation and Resorption and Protects against Inflammatory Bone Loss

2021 ◽  
Vol 22 (5) ◽  
pp. 2303
Author(s):  
Liang Li ◽  
Ming Yang ◽  
Saroj Kumar Shrestha ◽  
Hyoungsu Kim ◽  
William H. Gerwick ◽  
...  
Keyword(s):  
Bone Loss ◽  
Transmembrane Protein ◽  
Osteoclast Differentiation ◽  
Mapk Signaling ◽  
Osteoclast Formation ◽  
Bone Diseases ◽  
Tartrate Resistant Acid Phosphatase ◽  
Nuclear Factor ◽  
Mineral Density ◽  
Multinucleated Cells

Osteoclasts, bone-specified multinucleated cells produced by monocyte/macrophage, are involved in numerous bone destructive diseases such as arthritis, osteoporosis, and inflammation-induced bone loss. The osteoclast differentiation mechanism suggests a possible strategy to treat bone diseases. In this regard, we recently examined the in vivo impact of kalkitoxin (KT), a marine product obtained from the marine cyanobacterium Moorena producens (previously Lyngbya majuscula), on the macrophage colony-stimulating factor (M-CSF) and on the receptor activator of nuclear factor κB ligand (RANKL)-stimulated in vitro osteoclastogenesis and inflammation-mediated bone loss. We have now examined the molecular mechanism of KT in greater detail. KT decreased RANKL-induced bone marrow-derived macrophages (BMMs) tartrate-resistant acid phosphatase (TRAP)-multinucleated cells at a late stage. Likewise, KT suppressed RANKL-induced pit area and actin ring formation in BMM cells. Additionally, KT inhibited several RANKL-induced genes such as cathepsin K, matrix metalloproteinase (MMP-9), TRAP, and dendritic cell-specific transmembrane protein (DC-STAMP). In line with these results, RANKL stimulated both genes and protein expression of c-Fos and nuclear factor of activated T cells (NFATc1), and this was also suppressed by KT. Moreover, KT markedly decreased RANKL-induced p-ERK1/2 and p-JNK pathways at different time points. As a result, KT prevented inflammatory bone loss in mice, such as bone mineral density (BMD) and osteoclast differentiation markers. These experiments demonstrated that KT markedly inhibited osteoclast formation and inflammatory bone loss through NFATc1 and mitogen-activated protein kinase (MAPK) signaling pathways. Therefore, KT may have potential as a treatment for destructive bone diseases.

Comparison Analysis on the Mechanical Properties of HSC and NSC after the Action of High Temperatures

2014 ◽  
Vol 1014 ◽  
pp. 49-52
Author(s):  
Xiao Ping Su
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
High Temperatures ◽  
High Strength Concrete ◽  
Elasticity Modulus ◽  
Strain Curve ◽  
Peak Stress ◽  
High Strength ◽  
Peak Strain ◽  
Strength Concrete

With the wide application of high strength concrete in the building construction,the risk making concrete subject to high temperatures during a fire is increasing. Comparison tests on the mechanical properties of high strength concrete (HSC) and normal strength concrete (NSC) after the action of high temperature were made in this article, which were compared from the following aspects: the peak stress, the peak strain, elasticity modulus, and stress-strain curve after high temperature. Results show that the laws of the mechanical properties of HSC and NSC changing with the temperature are the same. With the increase of heating temperature, the peak stress and elasticity modulus decreases, while the peak strain grows rapidly. HSC shows greater brittleness and worse fire-resistant performance than NSC, and destroys suddenly. The research and evaluation on the fire-resistant performance of HSC should be strengthened during the structural design and construction on the HSC buildings.

scholarly journals Jumping exercise preserves bone mineral density and mechanical properties in osteopenic ovariectomized rats even following established osteopenia

2017 ◽  
Vol 28 (4) ◽  
pp. 1461-1471 ◽  
Author(s):  
R . Okubo ◽  
L. S. Sanada ◽  
V. A. Castania ◽  
M. J. Q. Louzada ◽  
F. J. A. de Paula ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bone Mineral Density ◽  
Bone Mineral ◽  
Ovariectomized Rats ◽  
Mineral Density ◽  
Jumping Exercise

Effects of Sintering Variables on the Physical and Mechanical Properties of Metal Injection Molding Molded 17-4 PH Stainless Steel

2021 ◽  
Vol 1028 ◽  
pp. 403-408
Author(s):  
Apang Djafar Shieddieque ◽  
Shinta Virdhian ◽  
Moch Iqbal Zaelana Muttahar ◽  
Muhammad Rafi Muttaqin
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Injection Molding ◽  
Relative Density ◽  
Physical And Mechanical Properties ◽  
High Hardness ◽  
Argon Atmosphere ◽  
Metal Injection Molding ◽  
Manufacturing Method ◽  
Small Complex

Metal injection molding (MIM) is a near net shape manufacturing technique for producing small, complex, precision parts in mass production. MIM process is manufacturing method that combines traditional shape-making capability of plastic injection molding and the materials flexibility of powder metallurgy. The process consists of the following four steps: mixing of metal powder and binder, injection molding to shape the component, debinding to remove the binder in the component, sintering to consolidate the debound parts. In this research, the physical and mechanical properties of metal injection molded 17-4 PH stainless steel were investigated with the variation of sintering temperatures (1300 °C - 1360 °C) and atmosphere conditions (argon and vacuum conditions). The relative density, microstructure, distortion, and hardness are measured and analyzed in this study. The results show that highest relative density of 87%, relative homogeneous shrinkage and high hardness are achieved by sintering at 1360 °C for 1.5 hours and argon atmosphere. At the same sintering temperature and time, sintering in vacuum shows lower relative density (81%) than that in argon condition due to pores growth. The pore growths were not observed in the argon atmosphere. It can be concluded that sintering stages more rapidly under vacuum condition. The hardness measurements result also showed that high hardness is obtained by high density parts. The optimum average hardness obtained in this study is 239 HV. However, the hardness properties results are still lower than 280 HV according to MPIF Standard 35 for MIM parts.

Mechanical properties and wear-corrosion resistance of a new compound extrusion process for magnesium alloy AZ61

2020 ◽  
Vol 62 (4) ◽  
pp. 395-399
Author(s):  
Jiehui Liu ◽  
Hongjun Hu ◽  
Yang Liu ◽  
Dingfei Zhang ◽  
Zhongwen Ou ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Magnesium Alloy ◽  
Equal Channel Angular Extrusion ◽  
Extrusion Process ◽  
Corrosion And Wear ◽  
Nacl Solution ◽  
Corrosion Properties ◽  
Manufacturing Method ◽  
Az61 Magnesium Alloy

Abstract Compound extrusion (CE) is a newly developed plastic deformation technique which combines direct extrusion (DE) with a two-pass equal channel angular extrusion (ECAE). This paper focuses on the strength, ductility and anti-corrosion properties of an NaCl solution at certain concentrations and the wear-resistance of dry sliding AZ61 magnesium alloy prepared by CE and DE. It is found that the strength and elongation of the AZ61 alloy prepared by CE are enhanced because of grain refinement. Furthermore, AZ61 magnesium alloy made by CE displays higher corrosion and wear resistance than that prepared by DE. Experimental results prove that CE is a prospective manufacturing method for improving the mechanical properties, anti-corrosion and anti-wear of AZ61 magnesium alloy.

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