scholarly journals Retrospective Evaluation and Framework Development of Bone Anisotropic Material Behavior Compared with Elastic, Elastic-Plastic, and Hyper-Elastic Properties

2021 ◽  
Vol 9 (1) ◽  
pp. 9
Author(s):  
Farah Hamandi ◽  
James T. Tsatalis ◽  
Tarun Goswami
Keyword(s):  
Bone Tissue ◽  
Material Properties ◽  
Anisotropic Material ◽  
Material Behavior ◽  
Imaging Data ◽  
Premature Failure ◽  
Elastic Plastic ◽  
Significant Difference ◽  
Hyper Elastic

The main motivation for studying damage in bone tissue is to better understand how damage develops in the bone tissue and how it progresses. Such knowledge may help in the surgical aspects of joint replacement, fracture fixation or establishing the fracture tolerance of bones to prevent injury. Currently, there are no standards that create a realistic bone model with anisotropic material properties, although several protocols have been suggested. This study seeks to retrospectively evaluate the damage of bone tissue with respect to patient demography including age, gender, race, body mass index (BMI), height, and weight, and their role in causing fracture. Investigators believe that properties derived from CT imaging data to estimate the material properties of bone tissue provides more realistic models. Quantifying and associating damage with in vivo conditions will provide the required information to develop mathematical equations and procedures to predict the premature failure and potentially mitigate problems before they begin. Creating a realistic model for bone tissue can predict the premature failure(s), provide preliminary results before getting the surgery, and optimize the design of orthopaedic implants. A comparison was performed between the proposed model and previous efforts, where they used elastic, hyper- elastic, or elastic-plastic properties. Results showed that there was a significant difference between the anisotropic material properties of bone when compared with unrealistic previous methods. The results showed that the density is 50% higher in male subjects than female subjects. Additionally, the results showed that the density is 47.91% higher in Black subjects than Mixed subjects, 53.27% higher than Caucasian subjects and 57.41% higher than Asian. In general, race should be considered during modeling implants or suggesting therapeutic techniques.

scholarly journals Microindentation for in vivo measurement of bone tissue material properties in atypical femoral fracture patients and controls

2012 ◽  
Vol 28 (1) ◽  
pp. 162-168 ◽  
Author(s):  
Roberto C Güerri-Fernández ◽  
Xavier Nogués ◽  
José M Quesada Gómez ◽  
Elisa Torres del Pliego ◽  
Lluís Puig ◽  
...  
Keyword(s):  
Bone Tissue ◽  
Material Properties ◽  
Femoral Fracture ◽  
Atypical Femoral Fracture ◽  
In Vivo Measurement ◽  
Tissue Material

scholarly journals Comparing Three Different Three-dimensional Scaffolds for Bone Tissue Engineering: An in vivo Study

2015 ◽  
Vol 16 (1) ◽  
pp. 25-30 ◽  
Author(s):  
Saeid Nosouhian ◽  
Amin Davoudi ◽  
Mansour Rismanchian ◽  
Sayed Mohammad Razavi ◽  
Hamidreza Sadeghiyan
Keyword(s):  
Tissue Engineering ◽  
Bone Tissue Engineering ◽  
Bone Tissue ◽  
Demineralized Bone Matrix ◽  
Bone Matrix ◽  
Three Dimensional ◽  
Control Group ◽  
Lamellar Bone ◽  
Significant Difference

ABSTRACT Introduction Three-dimensional Scaffold structure of synthetic biomaterials with their interconnected spaces seem to be a safe and effective option in supporting bone regeneration. The aim of this animal study was to compare the effectiveness of three different biocompatible scaffolds: bioglass (BG), demineralized bone matrix (DBM) and forstrite (FR). Materials and methods Four healthy dogs were anesthetized and the first to fourth premolars were extracted atraumatically in each quadrant. After healing, linear incision was prepared from molar to anterior segment and 4 defects in each quadrant (16 defects in each dog) were prepared. Scaffold blocks of BG, DBM and FR were resized according to size of defects and placed in the 12 defects randomly, 4 defects remained as control group. The dogs were sacrificed in 4 time intervals (15, 30, 45 and 60 days after) and the percentage of different types of regenerated bones (lamellar and woven) and connective tissue were recorded in histological process. The data were analyzed by one-way ANOVA and post hoc using SPSS software Ver. 15 at significant level of 0.05. Results In day 30th, although the amount of regenerated lamellar bone in control, DBM and BG Scaffold (22.37 ± 3.44; 21.46 ± 1.96; 21.21 ± 0.96) were near to each, the FR Scaffold provided the highest amount of lamellar (29.71 ± 7.94) and woven bone (18.28 ± 2.35). Also, FR Scaffold showed significant difference with BG (p = 0.026) and DBM Scaffolds (p = 0.032) in regenerated lamellar bone. Conclusion We recommend paying more attention to FR Scaffold as a biomaterial, but it is better to be compared with other nano biomaterials in future studies. How to cite this article Rismanchian M, Nosouhian S, Razavi SM, Davoudi A, Sadeghiyan H. Comparing Three Different Threedimensional Scaffolds for Bone Tissue Engineering: An in vivo Study. J Contemp Dent Pract 2015;16(1):25-30.

scholarly journals Anisotropic Material Characterization of Human Cervix Tissue Based on Indentation and Inverse Finite Element Analysis

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
Lei Shi ◽  
Wang Yao ◽  
Yu Gan ◽  
Lily Y. Zhao ◽  
W. Eugene McKee ◽  
...  
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Fiber Composite ◽  
Material Behavior ◽  
Ground Substance ◽  
Cervical Tissue ◽  
Constitutive Material Model ◽  
Significant Difference ◽  
Anisotropic Mechanical Properties ◽  
Human Cervix

The cervix is essential to a healthy pregnancy as it must bear the increasing load caused by the growing fetus. Preterm birth is suspected to be caused by the premature softening and mechanical failure of the cervix. The objective of this paper is to measure the anisotropic mechanical properties of human cervical tissue using indentation and video extensometry. The human cervix is a layered structure, where its thick stromal core contains preferentially aligned collagen fibers embedded in a soft ground substance. The fiber composite nature of the tissue provides resistance to the complex three-dimensional loading environment of pregnancy. In this work, we detail an indentation mechanical test to obtain the force and deformation response during loading which closely matches in vivo conditions. We postulate a constitutive material model to describe the equilibrium material behavior to ramp-hold indentation, and we use an inverse finite element method based on genetic algorithm (GA) optimization to determine best-fit material parameters. We report the material properties of human cervical slices taken at different anatomical locations from women of different obstetric backgrounds. In this cohort of patients, the anterior internal os (the area where the cervix meets the uterus) of the cervix is stiffer than the anterior external os (the area closest to the vagina). The anatomic anterior and posterior quadrants of cervical tissue are more anisotropic than the left and right quadrants. There is no significant difference in material properties between samples of different parities (number of pregnancies reaching viable gestation age).

scholarly journals 3D Printed Biomimetic Rabbit Airway Simulation Model for Nasotracheal Intubation Training

2020 ◽  
Vol 7 ◽  
Author(s):  
Gunpreet Oberoi ◽  
M. C. Eberspächer-Schweda ◽  
Sepideh Hatamikia ◽  
Markus Königshofer ◽  
Doris Baumgartner ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Nasotracheal Intubation ◽  
Soft Materials ◽  
Tactile Feedback ◽  
Material Behavior ◽  
Imaging Data ◽  
Micro Computed Tomography ◽  
Inhalation Anesthesia ◽  
Significant Difference ◽  
3D Printed

Rabbit inhalation anesthesia by endotracheal intubation involves a higher risk among small animals owing to several anatomical and physiological features, which is pathognomonic to this species of lagomorphs. Rabbit-specific airway devices have been designed to prevent misguided intubation attempts. However, it is believed that expert anesthetic training could be a boon in limiting the aftermaths of this procedure. Our research is aimed to develop a novel biomimetic 3D printed rabbit airway model with representative biomechanical material behavior and radiodensity. Imaging data were collected for two sacrificed rabbit heads using micro-computed tomography (μCT) and micro-magnetic resonance imaging for the first head and cone beam computed tomography (CBCT) for the second head. Imaging-based life-size musculoskeletal airway models were printed using polyjet technology with a combination of hard and soft materials in replicates of three. The models were evaluated quantitatively for dimensional accuracy and radiodensity and qualitatively using digital microscopy and endoscopy for technical, tactic, and visual realism. The results displayed that simulation models printed with polyjet technology have an overall surface representation of 93% for μCT-based images and 97% for CBCT-based images within a range of 0.0–2.5 mm, with μCT showing a more detailed reproduction of the nasotracheal anatomy. Dimensional discrepancies can be caused due to inadequate support material removal and due to the limited reconstruction of microstructures from the imaging on the 3D printed model. The model showed a significant difference in radiodensities in hard and soft tissue regions. Endoscopic evaluation provided good visual and tactile feedback, comparable to the real animal. Overall, the model, being a practical low-cost simulator, comprehensively accelerates the learning curve of veterinary nasotracheal intubation and paves the way for 3D simulation-based image-guided interventional procedures.

scholarly journals Serum parathyroid hormone, but not menopausal status, is associated with the expression of osteoprotegerin and RANKL mRNA in human bone samples

2001 ◽  
pp. 199-205 ◽  
Author(s):  
T Seck ◽  
I Diel ◽  
H Bismar ◽  
R Ziegler ◽  
J Pfeilschifter
Keyword(s):  
Parathyroid Hormone ◽  
Bone Tissue ◽  
Menopausal Status ◽  
Osteoclast Differentiation ◽  
Human Bone ◽  
Significant Difference ◽  
Human Bone Tissue ◽  
Receptor Activator ◽  
Serum Pth

OBJECTIVE: Osteoprotegerin (OPG) and its ligand 'receptor activator of NF-kB ligand' (RANKL) are important regulators of bone metabolism. RANKL, expressed in osteoblasts, activates osteoclast differentiation and osteoclast function by binding the 'receptor activator of NF-kB' (RANK), expressed in ostoclast precursors and mature osteoclasts. The effect is prevented by OPG, a soluble receptor of RANKL. In vitro studies have suggested that estrogen stimulates OPG, whereas parathyroid hormone (PTH) inhibits OPG expression and stimulates the expression of RANKL. DESIGN: In the present study, we examined the relationship between the menopause, serum PTH and the expression of OPG and RANKL in human bone tissue in vivo. METHODS: To address this question, we established a 5'-nuclease assay to quantify the mRNA copies of human OPG and RANKL, normalized to the number of copies of beta-actin mRNA in 169 women (mean age: 52.4+/-11.6 years), who underwent surgery for early breast cancer. Intact serum PTH was measured by chemoluminescence in 61 women. RESULTS: We found no significant difference in the expression of OPG and RANKL between postmenopausal women and premenopausal women. Also, the ratio of RANKL to OPG was unchanged in relation to the menopausal status. Serum PTH was negatively associated with the expression of OPG (r=-0.33, P=0.01), but also, surprisingly, with the expression of RANKL (r=-0.28, P=0.03). CONCLUSION: We failed to observe the expected changes in the expression of OPG and RANKL in human bone samples at menopause. High in vivo levels of circulating PTH are accompanied by low levels of expression of the two transcripts in human bone tissue.

scholarly journals Identification of Material Parameters of a Hyper-Elastic Body With Unknown Boundary Conditions

2018 ◽  
Vol 85 (5) ◽  
Author(s):  
M. Hajhashemkhani ◽  
M. R. Hematiyan ◽  
S. Goenezen
Keyword(s):  
Boundary Conditions ◽  
Elastic Material ◽  
Material Properties ◽  
Soft Tissues ◽  
Material Model ◽  
Unknown Boundary ◽  
Material Parameters ◽  
Hyper Elastic ◽  
Unknown Boundary Conditions

Identification of material properties of hyper-elastic materials such as soft tissues of the human body or rubber-like materials has been the subject of many works in recent decades. Boundary conditions generally play an important role in solving an inverse problem for material identification, while their knowledge has been taken for granted. In reality, however, boundary conditions may not be available on parts of the problem domain such as for an engineering part, e.g., a polymer that could be modeled as a hyper-elastic material, mounted on a system or an in vivo soft tissue. In these cases, using hypothetical boundary conditions will yield misleading results. In this paper, an inverse algorithm for the characterization of hyper-elastic material properties is developed, which takes into consideration unknown conditions on a part of the boundary. A cost function based on measured and calculated displacements is defined and is minimized using the Gauss–Newton method. A sensitivity analysis is carried out by employing analytic differentiation and using the finite element method (FEM). The effectiveness of the proposed method is demonstrated through numerical and experimental examples. The novel method is tested with a neo–Hookean and a Mooney–Rivlin hyper-elastic material model. In the experimental example, the material parameters of a silicone based specimen with unknown boundary condition are evaluated. In all the examples, the obtained results are verified and it is observed that the results are satisfactory and reliable.

scholarly journals Disturbed Expression of EphB4, but Not EphrinB2, Inhibited Bone Regeneration in an In Vivo Inflammatory Microenvironment

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Li-Li Shen ◽  
Li-Xia Zhang ◽  
Li-Mei Wang ◽  
Rong-Jing Zhou ◽  
Cheng-Zhe Yang ◽  
...  
Keyword(s):  
Bone Regeneration ◽  
Bone Tissue ◽  
Bone Defects ◽  
Marker Genes ◽  
Ctrl Group ◽  
Expression Levels ◽  
Inflammatory Microenvironment ◽  
Chemical Structures ◽  
Significant Difference

The important role of ephrinB2-EphB4 signaling pathway in bone remodeling has been well established. However, it is still unclear whether this bidirectional signaling also has effects on the regenerative processes of bone defects created in an inflammatory microenvironment. In this study, an experimental animal model of bone defects treated with lentiviruses was prepared and an inflammatory microenvironment was established. Expression levels of bone marker genes were monitored in the newly formed bone tissue using quantitative reverse transcriptase polymerase chain reaction and western blot. Immunohistochemical (IHC) staining and histomorphometric analysis were also performed to evaluate bone healing processes. Compared with the pLenti6.3-ctrl group, the pLenti6.3-ephb4siRNA group exhibited lower expression levels of bone formation marker genes and a higher level of NFATc1 in the new bone tissue. In addition, the newly formed bone was thinner and the number of giant osteoclasts was higher in the pLenti6.3-ephb4siRNA group than that in the pLenti6.3-ctrl group. In contrast, there was no significant difference between the pLenti6.3-efnb2siRNA group and the pLenti6.3-ctrl group. In conclusion, EphB4 plays an irreplaceable role in bone regeneration in an inflammatory microenvironment, whereas the functional loss of ephrinB2 can be effectively compensated, most possibly by other ephrins with similar chemical structures.

In-vivo evaluation of the effect of cyanoacrylate on prosthetic vascular graft infection – does cyanoacrylate increase the severity of infection?

VASA ◽  
2020 ◽  
Vol 49 (4) ◽  
pp. 281-284
Author(s):  
Atıf Yolgosteren ◽  
Gencehan Kumtepe ◽  
Melda Payaslioglu ◽  
Cuneyt Ozakin
Keyword(s):  
Vascular Graft ◽  
Graft Infection ◽  
Vascular Graft Infection ◽  
Group 4 ◽  
Significant Difference ◽  
Group 3 ◽  
Group 2 ◽  
Prosthetic Vascular Graft Infection ◽  
Group 1

Summary. Background: Prosthetic vascular graft infection (PVGI) is a complication with high mortality. Cyanoacrylate (CA) is an adhesive which has been used in a number of surgical procedures. In this in-vivo study, we aimed to evaluate the relationship between PVGI and CA. Materials and methods: Thirty-two rats were equally divided into four groups. Pouch was formed on back of rats until deep fascia. In group 1, vascular graft with polyethyleneterephthalate (PET) was placed into pouch. In group 2, MRSA strain with a density of 1 ml 0.5 MacFarland was injected into pouch. In group 3, 1 cm 2 vascular graft with PET piece was placed into pouch and MRSA strain with a density of 1 ml 0.5 MacFarland was injected. In group 4, 1 cm 2 vascular graft with PET piece impregnated with N-butyl cyanoacrylate-based adhesive was placed and MRSA strain with a density of 1 ml 0.5 MacFarland was injected. All rats were scarified in 96th hour, culture samples were taken where intervention was performed and were evaluated microbiologically. Bacteria reproducing in each group were numerically evaluated based on colony-forming unit (CFU/ml) and compared by taking their average. Results: MRSA reproduction of 0 CFU/ml in group 1, of 1410 CFU/ml in group 2, of 180 200 CFU/ml in group 3 and of 625 300 CFU/ml in group 4 was present. A statistically significant difference was present between group 1 and group 4 (p < 0.01), between group 2 and group 4 (p < 0.01), between group 3 and group 4 (p < 0.05). In terms of reproduction, no statistically significant difference was found in group 1, group 2, group 3 in themselves. Conclusions: We observed that the rate of infection increased in the cyanoacyrylate group where cyanoacrylate was used. We think that surgeon should be more careful in using CA in vascular surgery.

In-vivo anti-oxidant screening of Tectona grandis extract

2020 ◽  
Vol 9 (1) ◽  
pp. 1-4
Author(s):  
Tamilarasi G P ◽  
Sabarees G
Keyword(s):  
Biochemical Parameters ◽  
Tectona Grandis ◽  
The Body ◽  
Altered Expression ◽  
Physiological Conditions ◽  
Synthetic Drugs ◽  
Significant Difference ◽  
Anti Oxidant ◽  
Radical Generation

Oxidation is an essential reaction in the human body, which determines the expression of proteins in the body. This results in the altered expression like rapid growth resulting in cancers and other disorders. Many synthetic drugs are available in the market that is effective in limiting the free radical generation and the reaction of radicals with cells. Unfortunately, all those synthetic drugs were found to cause side effects and adverse effects in the body. But given the accuracy of the predictability of the results and administration, this research focuses on testing the anti-oxidant efficiency in rat models testing the biochemical parameters. Investigations have also been done on the anti-oxidant activity of Tectona, but every research was concentrated to prove the anti-oxidant activity only. extract had been tested for anti-oxidant activity by estimating various tissue parameters and it showed better activity. As predicted, there is a significant difference in the and results which can be explained are due to the physiological conditions that exist inside the body.

Alternativas farmacéuticas: ¿pueden ser intercambiables?

2020 ◽  
Vol 2 (2) ◽  
pp. 38-42
Author(s):  
Miriam del Carmen Carrasco-Portugal ◽  
Francisco Javier Flores-Murrieta
Keyword(s):  
Generic Substitution ◽  
In Vivo Studies ◽  
Regulatory Agencies ◽  
European Medicines Agency ◽  
Reference Formulation ◽  
Active Moiety ◽  
Significant Difference ◽  
Pharmaceutical Form ◽  
Extent Of Absorption

Pharmaceutical alternatives are products with the same active moiety, but different salt, ester or pharmaceutical form. Regulatory agencies have different criteria for this kind of drug. The European Medicines Agency (EMA) accepts the generic substitution using these alternatives, whereas the Food and Drug Administration (FDA) only authorizes generic substitution of pharmaceutical equivalents. The objective of this paper is to describe some relevant aspects that should be considered before deciding on making a generic substitution with pharmaceutical alternatives. It is important to note that a pharmaceutical alternative must show no significant difference in the rate and extent of absorption (bioequivalence) in a well-conducted in vivo study when compared with the reference formulation. Current Mexican regulations state that generic substitution is possible using pharmaceutical alternatives when bioequivalence is demonstrated in in vivo studies conducted under the NOM-177-SSA1-2013 criteria. In conclusion, generic substitution with pharmaceutical alternatives is possible if these products demonstrate in vivo bioequivalence when compared with the reference product.

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