scholarly journals Evaluating the value of synchrotron radiation phase-contrast CT imaging in the study of knee joint microstructure

2021 ◽  
Vol 271 ◽  
pp. 03039
Author(s):  
Meibai Tang ◽  
Richeng Zhi ◽  
Changyi Sun ◽  
Xiaohua Wang ◽  
Chenglin Liu
Keyword(s):  
Synchrotron Radiation ◽  
Knee Joint ◽  
Volume Fraction ◽  
Layer Structure ◽  
Ct Imaging ◽  
Micro Structure ◽  
Bone Volume Fraction ◽  
Mesh Structure ◽  
Contrast Analysis ◽  
Epiphyseal Bone

The knee joint is one of the tissues that often appear diseased, and the pathogenesis owing to its structure. Therefore, the micro-structure of the knee joint was studied by synchrotron radiation phasecontrast CT imaging (SRPCI-CT). The contrast and the sharpness of the reconstructed slice were calculated and analysed. From these results, the layer structure of the joint tissue can be seen. The cartilage layer (including the meniscus) is about 1.44 mm, and the epiphyseal layer is about 2.25 mm, which conforms to the actual situation of rat knees. From the 3D images, the structure of the meniscus and the epiphyseal bone can be observed. The epiphyseal bone line is also particularly obvious. Simultaneously, the epiphyseal bone also has a mesh structure, which has the characteristics of both cartilage and tibia. Further research on the tibia can determine that the trabecular bone line is about 130 microns. Finally, the bone volume fraction (BVF) of the joint, the data also reflect the existence of a layer structure, and its scale distribution is consistent with the results of sharpness and contrast analysis. The SRPCI-CT can play an important role in the study micro-structure of joints.

КОНСТРУКТИВНО-ТЕХНОЛОГІЧНІ ОСОБЛИВОСТІ ХВОСТО-ВИХ БАЛОК СІТЧАСТОГО ТИПУ З ПОЛІМЕРНИХ КОМПО-ЗИЦІЙНИХ МАТЕРІАЛІВ ВЕРТОЛЬОТІВ ТРАНСПОРТНОЇ КАТЕГОРІЇ

2020 ◽  
pp. 15-30
Author(s):  
А. Г. Гребеников ◽  
И. В. Малков ◽  
В. А. Урбанович ◽  
Н. И. Москаленко ◽  
Д. С. Колодийчик
Keyword(s):  
Finite Element ◽  
Strain State ◽  
Layer Structure ◽  
Metal Structure ◽  
Element Model ◽  
Stress Strain ◽  
Element Analysis ◽  
Mesh Structure ◽  
Stress Strain State ◽  
Mesh Structures

The analysis of the design and technological features of the tail boom (ТB) of a helicopter made of polymer composite materials (PCM) is carried out.Three structural and technological concepts are distinguished - semi-monocoque (reinforced metal structure), monocoque (three-layer structure) and mesh-type structure. The high weight and economic efficiency of mesh structures is shown, which allows them to be used in aerospace engineering. The physicomechanical characteristics of the network structures are estimated and their uniqueness is shown. The use of mesh structures can reduce the weight of the product by a factor of two or more.The stress-strain state (SSS) of the proposed tail boom design is determined. The analysis of methods for calculating the characteristics of the total SSS of conical mesh shells is carried out. The design of the tail boom is presented, the design diagram of the tail boom of the transport category rotorcraft is developed. A finite element model was created using the Siemens NX 7.5 system. The calculation of the stress-strain state (SSS) of the HC of the helicopter was carried out on the basis of the developed structural scheme using the Advanced Simulation module of the Siemens NX 7.5 system. The main zones of probable fatigue failure of tail booms are determined. Finite Element Analysis (FEA) provides a theoretical basis for design decisions.Shown is the effect of the type of technological process selected for the production of the tail boom on the strength of the HB structure. The stability of the characteristics of the PCM tail boom largely depends on the extent to which its design is suitable for the use of mechanized and automated production processes.A method for the manufacture of a helicopter tail boom from PCM by the automated winding method is proposed. A variant of computer modeling of the tail boom of a mesh structure made of PCM is shown.The automated winding technology can be recommended for implementation in the design of the composite tail boom of the Mi-2 and Mi-8 helicopters.

scholarly journals Bone health in spacefaring rodents and primates: systematic review and meta-analysis

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Jingyan Fu ◽  
Matthew Goldsmith ◽  
Sequoia D. Crooks ◽  
Sean F. Condon ◽  
Martin Morris ◽  
...  
Keyword(s):  
Bone Formation ◽  
Trabecular Bone ◽  
Bone Health ◽  
Volume Fraction ◽  
Meta Analysis ◽  
Bone Volume ◽  
Trabecular Bone Volume ◽  
Bone Volume Fraction ◽  
Percentage Difference ◽  
Induced Changes

AbstractAnimals in space exploration studies serve both as a model for human physiology and as a means to understand the physiological effects of microgravity. To quantify the microgravity-induced changes to bone health in animals, we systematically searched Medline, Embase, Web of Science, BIOSIS, and NASA Technical reports. We selected 40 papers focusing on the bone health of 95 rats, 61 mice, and 9 rhesus monkeys from 22 space missions. The percentage difference from ground control in rodents was –24.1% [Confidence interval: −43.4, −4.9] for trabecular bone volume fraction and –5.9% [−8.0, −3.8] for the cortical area. In primates, trabecular bone volume fraction was lower by –25.2% [−35.6, −14.7] in spaceflight animals compared to GC. Bone formation indices in rodent trabecular and cortical bone were significantly lower in microgravity. In contrast, osteoclast numbers were not affected in rats and were variably affected in mice. Thus, microgravity induces bone deficits in rodents and primates likely through the suppression of bone formation.

scholarly journals Biaxial Normal Strength Behavior in the Axial-Transverse Plane for Human Trabecular Bone—Effects of Bone Volume Fraction, Microarchitecture, and Anisotropy

2013 ◽  
Vol 135 (12) ◽  
Author(s):  
Arnav Sanyal ◽  
Tony M. Keaveny
Keyword(s):  
Trabecular Bone ◽  
Volume Fraction ◽  
Elastic Anisotropy ◽  
Bone Volume ◽  
Transverse Plane ◽  
Mechanical Anisotropy ◽  
Bone Volume Fraction ◽  
Human Trabecular Bone ◽  
Strength Behavior ◽  
Normal Strength

The biaxial failure behavior of the human trabecular bone, which has potential relevance both for fall and gait loading conditions, is not well understood, particularly for low-density bone, which can display considerable mechanical anisotropy. Addressing this issue, we investigated the biaxial normal strength behavior and the underlying failure mechanisms for human trabecular bone displaying a wide range of bone volume fraction (0.06–0.34) and elastic anisotropy. Micro-computed tomography (CT)-based nonlinear finite element analysis was used to simulate biaxial failure in 15 specimens (5 mm cubes), spanning the complete biaxial normal stress failure space in the axial-transverse plane. The specimens, treated as approximately transversely isotropic, were loaded in the principal material orientation. We found that the biaxial stress yield surface was well characterized by the superposition of two ellipses—one each for yield failure in the longitudinal and transverse loading directions—and the size, shape, and orientation of which depended on bone volume fraction and elastic anisotropy. However, when normalized by the uniaxial tensile and compressive strengths in the longitudinal and transverse directions, all of which depended on bone volume fraction, microarchitecture, and mechanical anisotropy, the resulting normalized biaxial strength behavior was well described by a single pair of (longitudinal and transverse) ellipses, with little interspecimen variation. Taken together, these results indicate that the role of bone volume fraction, microarchitecture, and mechanical anisotropy is mostly accounted for in determining the uniaxial strength behavior and the effect of these parameters on the axial-transverse biaxial normal strength behavior per se is minor.

Joining between Ceramics and Metal in Composite Pipes Fabricated by the SHS Metallurgical Process

2007 ◽  
Vol 280-283 ◽  
pp. 887-890
Author(s):  
Zhong Min Zhao ◽  
Long Zhang ◽  
Jian Jiang Wang ◽  
Shi Yan ◽  
Jin Rong Cao
Keyword(s):  
High Performance ◽  
Volume Fraction ◽  
Layer Structure ◽  
Mechanical Test ◽  
Steel Substrate ◽  
Low Cost ◽  
Metallurgical Process ◽  
Ni Powder ◽  
Suitable Amount ◽  
Composite Pipes

The design on joining of metal and ceramics in composite pipes fabricated by the SHS metallurgical process is carried on with adding (TiO2 +Al+C+Ni) subsystem in(CrO3+Al) system, and the composite pipes with three-layer structure of steel substrate, intermediate alloy and lined ceramics are fabricated with low cost and high performance. Combustion determination and mechanical test indicate that adding suitable amount of Ni powder in combustion system rather than (NiO+Al) subsystem can cause combustion behavior of a whole system and volume fraction of the carbides to be controlled easily, and is beneficial to improve joining of the intermediate alloy and steel substrate, causing compression strength and compression shear strength of the composite pipes to be increased greatly.

Architectural changes of trabecular bone caused by the remodeling process

2005 ◽  
Vol 874 ◽  
Author(s):  
Richard Weinkamer ◽  
Markus A. Hartmann ◽  
Yves Brechet ◽  
Peter Fratzl
Keyword(s):  
Trabecular Bone ◽  
Feedback Loop ◽  
Mechanical Response ◽  
Volume Fraction ◽  
Bone Volume ◽  
Bone Architecture ◽  
Mechanical Problem ◽  
Bone Volume Fraction ◽  
Obvious Effect ◽  
Trabecular Bone Architecture

AbstractUsing a stochastic lattice model we have studied the architectural changes of trabecular bone occurring while the structure is remodeled. Our model considers the mechanical feedback loop, which control the remodeling process. A fast algorithm was employed to solve approximately the mechanical problem. A general feature of the model is that a networklike structure emerges, which further coarsens while the bone volume fraction remains unchanged. Decreasing the mechanical response of the system by either lowering the external load or the internal mechano-sensitivity leads not only to a reduction of the bone volume fraction, but results in topological changes of the trabecular bone architecture, where the loss of horizontal trabeculae is the most obvious effect.

scholarly journals Alpha-Ketoglutarate: An Effective Feed Supplement in Improving Bone Metabolism and Muscle Quality of Laying Hens: A Preliminary Study

Animals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2420
Author(s):  
Ewa Tomaszewska ◽  
Sylwester Świątkiewicz ◽  
Anna Arczewska-Włosek ◽  
Dorota Wojtysiak ◽  
Piotr Dobrowolski ◽  
...  
Keyword(s):  
Matrix Protein ◽  
Laying Hens ◽  
Volume Fraction ◽  
Basal Diet ◽  
Cholesterol Content ◽  
Muscle Quality ◽  
Control Group ◽  
Bone Volume Fraction ◽  
Trabecular Thickness ◽  
Laying Performance

The aim of the experiment was to assess the effect of dietary alpha-ketoglutarate (AKG) supplementation on performance, serum hormonal indices, duodenum and jejunum histomorphometry, meat quality characteristics, bone quality traits and cartilage degradation in laying hens with a mature skeletal system. Forty-eight 30 week-old Bovans Brown laying hens were randomly assigned to a control group or the group fed the basal diet plus 1.0% AKG. The experimental trial lasted 30 weeks. The supplementation of AKG increases blood serum content of leptin, ghrelin, bone alkaline phosphatate and receptor activator of nuclear factor kappa-Β ligand, while osteoprotegerin and osteocalcin decrease. While dietary AKG was given to laying hens negatively influenced villus length, crypt depth, villus/crypt ratio and absorptive surface area in duodenum and jejunum, these changes have no effect on feed intake, weight gain, nor laying performance. In breast muscles, no significant changes in skeletal muscle fatty acid composition were observed, however, a higher shear force and decreased cholesterol content following AKG supplementation were noted, showing the improvement of muscle quality. While dietary AKG supplementation did not affect the general geometric and mechanical properties of the tibia, it increased collagen synthesis and enhanced immature collagen content. In medullary bone, an increase of bone volume fraction, trabecular thickness, fractal dimension and decrease of trabecular space were observed in AKG supplemented group. The trabeculae in bone metaphysis were also significantly thicker after AKG supplementation. AKG promoted fibrillogenesis in articular cartilage, as indicated by increased cartilage oligomeric matrix protein immunoexpression. By improving the structure and maintaining the proper bone turnover rate of highly reactive and metabolically active medullar and trabecular bones AKG showed its anti-osteoporotic action in laying hens.

scholarly journals Trabecular bone patterning in the hominoid distal femur

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5156 ◽  
Author(s):  
Leoni Georgiou ◽  
Tracy L. Kivell ◽  
Dieter H. Pahr ◽  
Matthew M. Skinner
Keyword(s):  
Trabecular Bone ◽  
Distal Femur ◽  
Volume Fraction ◽  
Reaction Force ◽  
Intraspecific Variability ◽  
Trabecular Structure ◽  
Trabecular Architecture ◽  
Micro Computed Tomography ◽  
Bone Volume Fraction ◽  
Distal Epiphysis

BackgroundIn addition to external bone shape and cortical bone thickness and distribution, the distribution and orientation of internal trabecular bone across individuals and species has yielded important functional information on how bone adapts in response to load. In particular, trabecular bone analysis has played a key role in studies of human and nonhuman primate locomotion and has shown that species with different locomotor repertoires display distinct trabecular architecture in various regions of the skeleton. In this study, we analyse trabecular structure throughout the distal femur of extant hominoids and test for differences due to locomotor loading regime.MethodsMicro-computed tomography scans ofHomo sapiens(n= 11),Pan troglodytes(n= 18),Gorilla gorilla(n= 14) andPongosp. (n= 7) were used to investigate trabecular structure throughout the distal epiphysis of the femur. We predicted that bone volume fraction (BV/TV) in the medial and lateral condyles inHomowould be distally concentrated and more anisotropic due to a habitual extended knee posture at the point of peak ground reaction force during bipedal locomotion, whereas great apes would show more posteriorly concentrated BV/TV and greater isotropy due to a flexed knee posture and more variable hindlimb use during locomotion.ResultsResults indicate some significant differences between taxa, with the most prominent being higher BV/TV in the posterosuperior region of the condyles inPanand higher BV/TV and anisotropy in the posteroinferior region inHomo. Furthermore, trabecular number, spacing and thickness differ significantly, mainly separatingGorillafrom the other apes.DiscussionThe trabecular architecture of the distal femur holds a functional signal linked to habitual behaviour; however, there was more similarity across taxa and greater intraspecific variability than expected. Specifically, there was a large degree of overlap in trabecular structure across the sample, andHomowas not as distinct as predicted. Nonetheless, this study offers a comparative sample of trabecular structure in the hominoid distal femur and can contribute to future studies of locomotion in extinct taxa.

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