Test Methods for Accurate and Robust Material Property Measurements of Rodent Cortical Bone

2008 ◽  
Author(s):  
Douglas J. Adams ◽  
Svetlana Lublinsky ◽  
Mauricio Barrero
Keyword(s):  
Cortical Bone ◽  
Material Property ◽  
Statistical Power ◽  
Test Methods ◽  
Standard Test ◽  
Long Bone ◽  
Long Bones ◽  
Tissue Properties ◽  
Serial Test ◽  
Direct Measurements

Direct measurements of cortical bone material properties are difficult to achieve in rodent long bones due to the inherently small dimensions and difficulties in machining standard test specimen geometries [1]. Bone tissue properties in nearly all rodent studies are thus limited to estimates from flexural tests of long bone diaphyses. In addition to the inaccuracies imposed by the bending stress state itself, these material property estimates are further confounded by the non-uniform geometry of long bones along the diaphyseal length. The goal of this work was to develop a series of techniques to improve the accuracy and precision of material property measurements in rodent long bones, with explicit mathematical correction for geometrical complexity and multiple measurements from individual bones. In combination, these techniques provide a pragmatic serial test routine for collecting multiple direct measurements of cortical tissue elastic modulus and strength, with a potential for improving sensitivity and statistical power in skeletal studies using rodents.

scholarly journals Comparative analysis of stress-strain state of mathematical models for an individual endoprosthesis and allocomposite endoprosthesis in case of replacement of long bone defects

TRAUMA ◽  
2021 ◽  
Vol 22 (4) ◽  
pp. 37-45
Author(s):  
O.E. Vyrva ◽  
Ya.О. Golovina ◽  
R.V. Malik ◽  
M.Yu. Karpinsky ◽  
О.V. Yaresko
Keyword(s):  
Mathematical Models ◽  
Bone Cement ◽  
Cortical Bone ◽  
Bone Tissue ◽  
Bone Grafting ◽  
Long Bone ◽  
Long Bones ◽  
Rigid Support ◽  
Stress Strain ◽  
Complete Replacement

Background. Replacement of post-resection defects of long bones in case of a tumor process is always an urgent problem of orthopedics. Among the wide variety of materials and methods for reconstruction of post-resection defects of long bones, the most common are individual, modular arthroplasty and bioreconstructive interventions. To study the mechanical properties of the structures we have chosen, various types of post-resection femoral bone defect replacement were simulated using the finite element method. The purpose was to compare the data on stress-strain states in mathematical models “allocomposite endoprosthesis” and “individual endoprosthesis” of the proximal femur. Material and methods. Mathematical models of the femur with the formation of a post-resection proximal defect replaced by a segmental bone allograft in combination with an individual endoprosthesis have been created. The model is presented in two versions, with the formation of transverse and step-cut osteotomy. Each model was examined separately with cement and cementless attachment in the area of the endoprosthesis stem. For comparison, we chose a model with complete replacement of the proximal end of the femur with an individual endoprosthesis without bone grafting. Results. Femur step-cut osteotomy can significantly reduce the level of stress in the osteotomy area. This is due to the fact that performing the step-cut osteotomy allows the bone fragments to provide resistance to shearing movement. The use of bone cement can significantly reduce the level of stress around the stem of the endoprosthesis in both variants of femoral osteotomy (transverse and step-cut). This is due to the fact that bone cement, which has an elastic modulus at an intermediate value between titanium and bone tissue, forms a layer between them, performs a damper function, that smoothes the difference in deformation values of the metal and bone tissue, thereby reducing the level of stress in them. Arthroplasty without performing bone grafting leads to increased stresses in the bone tissue due to the presence of a rigid support on the cortical bone endoprosthesis in the diaphysis along the line of its resection. Conclusions. Performing step-cut osteotomy of the femur reduces the level of mechanical stresses in the osteotomy area by half compared to models with transverse osteotomy, which is of particular importance in the early postoperative stages. The use of bone cement for fixing the stem of the endoprosthesis can also significantly reduce the level of stress in all variants of the studied models, due to the formation of a damping layer between the metal and the bone tissue. The level of stress in models without bone grafting does not depend on the use of bone cement, but is determined by the presence of a rigid support of the endoprosthesis on the cortical bone along the line of its resection.

scholarly journals Comparison of Two Intergranular Corrosion Tests on EN AW-6016 Sheet Material

2021 ◽  
Vol 11 (11) ◽  
pp. 5294
Author(s):  
Peer Decker ◽  
Ines Zerbin ◽  
Luisa Marzoli ◽  
Marcel Rosefort
Keyword(s):  
Optical Microscopy ◽  
Intergranular Corrosion ◽  
Sheet Material ◽  
Test Methods ◽  
Standard Test ◽  
Corrosion Depth ◽  
Corrosion Tests ◽  
Automotive Company ◽  
Test Parameters

Two different intergranular corrosion tests were performed on EN AW-6016 sheet material, an ISO 11846:1995-based test with varying solution amounts and acid concentrations, and a standard test of an automotive company (PV1113, VW-Audi). The average intergranular corrosion depth was determined via optical microscopy. The differences in the intergranular corrosion depths were then discussed with regard to the applicability and quality of the two different test methods. The influence of varying test parameters for ISO 11846:1995 was discussed as well. The determined IGC depths were found to be strongly dependent on the testing parameters, which will therefore have a pronounced influence on the determined IGC susceptibility of a material. In general, ISO 11846:1995 tests resulted in a significantly lower corrosion speed, and the corrosive attack was found to be primarily along grain boundaries.

scholarly journals Collagen heterogeneity within different growth regions of long bones of rachitic and nonrachitic chicks

1972 ◽  
Vol 127 (4) ◽  
pp. 715-720 ◽  
Author(s):  
Bryan P. Toole ◽  
Andrew H. Kang ◽  
Robert L. Trelstad ◽  
Jerome Gross
Keyword(s):  
Vitamin D ◽  
Amino Acid ◽  
Bone Matrix ◽  
Bone Collagen ◽  
Long Bone ◽  
Long Bones ◽  
Collagen Structure ◽  
Collagen Molecules ◽  
Relationship Of ◽  
Chain Type

The different anatomical regions involved in osteogenesis in the chick long bone have been examined for heterogeneities in collagen structure that might relate to the mechanism of ossification. Experimentally induced lathyrism was employed to enhance collagen solubility, and vitamin D deficiency to allow accumulation of osteoid, the precursor of bone matrix. The extractable lathyritic collagens of the cartilaginous and osseous regions of growing long bones from rachitic and non-rachitic chicks were examined for α-chain type and amino acid composition. In both groups of animals the growth plate and cartilaginous regions of the epiphysis gave collagen molecules of the constitution [α1(II)]3, whereas the ossifying regions contained [α1(I)]2 α2. The degree of hydroxylation of the lysine moieties was increased by approximately 50% in the α1(I)-chain and α2-chain of rachitic bone collagen. Since uncalcified osteoid is greatly enriched in rachitic bone, it is concluded that the collagen of osteoid has the configuration [α1(I)]2 α2, similar to that of bone matrix, but has an elevated hydroxylysine content. The possible relationship of this difference to the mechanism of calcification is discussed.

Serviceability Assessment of a Printed Finish on T-Shirts

2021 ◽  
Vol 8 (2) ◽  
pp. 48-53
Author(s):  
Reannan Riedy ◽  
Meredith McQuerry
Keyword(s):  
Abrasion Resistance ◽  
Dimensional Change ◽  
Test Methods ◽  
Standard Test ◽  
Performance Expectations ◽  
Agricultural Worker ◽  
Soil Release ◽  
And Performance ◽  
Typical Consumer ◽  
Change Material

To improve the comfort of agricultural workers, a T-shirt with a printed active cooling finish was evaluated to determine if it would meet the wash life durability and performance expectations of such an arduous application. Six shirts with a printed phase change material (PCM) finish and six shirts without (control) were washed 50 times to replicate a typical consumer wash life. Shirts were evaluated for absorbency, dimensional change, colorfastness, crocking, abrasion resistance, soil release, and smoothness retention according to AATCC and ASTM standard test methods. Testing was conducted before laundering and after 1, 5, 10, 20, 30, 35, 40, 45, and 50 consumer laundry (CL) cycles. Absorbency and dimensional change were significantly influenced by the PCM finish. Results demonstrate the appropriateness of adopting such a finish technology for agricultural worker clothing applications.

Development of standard test methods for unmanned and manned industrial vehicles used near humans

2013 ◽  
Author(s):  
Roger Bostelman ◽  
Richard Norcross ◽  
Joe Falco ◽  
Jeremy Marvel
Keyword(s):  
Test Methods ◽  
Standard Test

Longitudinal bone growth in vitro: effects of insulin-like growth factor I and growth hormone

1991 ◽  
Vol 124 (5) ◽  
pp. 602-607 ◽  
Author(s):  
Ben A. A. Scheven ◽  
Nicola J. Hamilton
Keyword(s):  
Growth Hormone ◽  
Growth Factor ◽  
Bone Growth ◽  
Long Bone ◽  
Long Bones ◽  
Insulin Like Growth Factor ◽  
Serum Free ◽  
Factor I ◽  
Igf I

Abstract. Longitudinal growth was studied using an in vitro model system of intact rat long bones. Metatarsal bones from 18- and 19-day-old rat fetuses, entirely (18 days) or mainly (19 days) composed of chondrocytes, showed a steady rate of growth and radiolabelled thymidine incorporation for at least 7 days in serum-free media. Addition of recombinant human insulin-like growth factor-I to the culture media resulted in a direct stimulation of the longitudinal growth. Recombinant human growth hormone was also able to stimulate bone growth, although this was generally accomplished after a time lag of more than 2 days. A monoclonal antibody to IGF-I abolished both the IGF-I and GH-stimulated growth. However, the antibody had no effect on the growth of the bone explants in control, serum-free medium. Unlike the fetal long bones, bones from 2-day-old neonatal rats were arrested in their growth after 1-2 days in vitro. The neonatal bones responded to IGF-I and GH in a similar fashion as the fetal bones. Thus in this study in vitro evidence of a direct effect of GH on long bone growth via stimulating local production of IGF by the growth plate chondrocytes is presented. Furthermore, endogenous growth factors, others than IGFs, appear to play a crucial role in the regulation of fetal long bone growth.

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