STUDIES ON THE PROPOGATION OF ELASTIC WAVES IN BOVINE COMPACT BONES AS A FUNCTION OF TEMPERATURE

To study the physical properties of biomaterials like bony hard tissues through the propagation of elastic waves is one of the most successful method.With the help of internal friction measurement, we can study the processes such as recrystallization, annealing, quenching and tempering, plastic deformation and strain ageing. In the present investigation we calculate and -1 reported the internal friction loss (Q ) for all the six types of bovine compact bones for the first time in a single experiment by using the ultrasonic piezoelectric composite oscillator technique with the help of X-cut crystal in different physiological conditions. Significant variation is observed from bone to bone. This may be attributed to composition and mineral content of the bones. Peak temperature data also is also determined. Temperature variation of logarithmic decrement in X-cut quartz transducer is also verified with mounting of bovine compact bar shaped bone -1 samples. Change of internal friction (Q ) with temperature is also calculated to predict the mechanism of acoustic losses and phase transitions in these bony hard tissues. Internal friction measurements are also useful to obtain the information about imperfections in bony hard tissues. The present investigation constitutes a step towards the application of natural bovine bone ceramic materials for the transducer applications

Internal Architecture Of Human Tali

Introduction: The talus is one of the seven tarsal bones. It is responsible for receiving the body weight andtransmitting it to the plantar arch below. The architecture of cancellous bone is based on its mechanical demands.The trabecular patterns of a bone are formed by the stress trajectories that are placed on that bone. The preferreddirectional orientation of the trabeculae thus provides a history of the stresses to which the bone has beensubjected.Aim: To study the internal architecture and pressure lines of human tali.Materials and Methods: 30 tali were dissected out from the formalin fixed lower limbs available at the Departmentof Anatomy of KVG Medical College, Sullia and they were dried and serial longitudinal (parasagittal), transverse(coronal) and horizontal sections of the bone were made in 10 each. The coronal sections were made at 3 levelsi.e at the body, neck and head. A good quality digital photograph of the cut surfaces were taken using a digitalcamera for analysis of the trabeculae of cancellous bone. Radiographs of the slices were also taken to study thepressure and the tension lines.Results: The sections showed an outer thin layer of compact bone, but it was much thicker at the neck of the talus.In the head, the cancellous bone was made of thick, parallel running semi-arched plates which consisted of twolimbs i.e vertical and horizontal which were continuous with each otherConclusion: It can be concluded that the part of compressive force, acting vertically downward on the body of thetalus during standing, was converted to tensile force in the neck, and its direction was made perpendicular, toenable this force to go toward the head of the talus. These findings may help in better understanding of fracturelines in the talus, which could improve internal fixation techniques, and help in designing of talar prosthesis.

Haversian system of compact bone and comparison between endosteal and periosteal sides using three-dimensional reconstruction in rat / 대한해부학회지

The current model of compact bone is that of a system of Haversian (longitudinal) canals connected by Volkmann's (transverse) canals. Models based on either histology or microcomputed tomography do not accurately represent the morphologic detail and microstructure of this system, especially that of the canal networks and their spatial relationships. The aim of the present study was to demonstrate the morphologic pattern and network of the Haversian system and to compare endosteal and periosteal sides in rats using three-dimensional (3D) reconstruction. Ten Sprague-Dawley rats aged 8-10 weeks were used. The femurs were harvested from each rat and fixed, decalcified with 10% EDTA-2Na, serially sectioned at a thickness of 5 microm, and then stained with hematoxylin and eosin. The serial sections were reconstructed three-dimensionally using Reconstruct software. The Haversian canals in the endosteal region were found to be large, highly interconnected, irregular, and close to neighboring canals. In contrast, the canals in the periosteal region were straight and small. This combined application of 3D reconstruction and histology examinations to the Haversian system has confirmed its microstructure, showing a branched network pattern on the endosteal side but not on the periosteal side.

Determination of the species from skeletal remains through histomorphometric evaluation and discriminant analysis / Determinación de la especie a partir de restos óseos mediante evaluación histomorfométrica y análisis discriminante

In situations where the skeletal remains found are too fragmented, it is necessary to assess the human origin of such remains; for this purpose, various parameters are used, both anatomical and histological. The objective of the present study is to evaluate the various histomorphometric parameters to differentiate human from non-human bones, to further construct discriminatory functions that allow interspecies classification. Tibia bones sections from human, bovine, pig, hen, cat, and dog species were used, processed through conventional histological techniques and observed under the microscope with a 40x magnification, analyzing the Haversian Canal Density parameters by mm2, Diameter of the Haversian Canal and the Diameter of the Haversian System which were compared through one way ANOVA with Scheffé post test, p<0.05. Subsequently, the discriminatory functions were constructed for each species and the percentage of well-diagnosed cases was determined. Meaningful differences were found in the parameters analyzed; the discriminatory functions allowed to correctly classify 88.5 percent of the cases. Our results suggest that it is possible to differentiate human skeletal remains from non-human through the observation of their histological characteristics and histomorphometric parameters, but interspecies differentiation requires a more complex analysis...

En situaciones donde los restos óseos que se encuentran están muy fragmentados, es necesario evaluar el origen humano de dichos restos, para ello se utilizan diversos parámetros morfológicos tanto anatómicos como histológicos. El propósito de este estudio fue evaluar los distintos parámetros histomorfométricos para diferenciar hueso humano de no humano, para posteriormente construir las funciones discriminantes que permitan la clasificación interespecies. Se utilizaron secciones de hueso de tibia de individuos de especies: humano, bovino, cerdo, gallina, gato y perro, procesadas mediante técnica histológica convencional y observadas al microscópio con aumento 40x, analizándose los parámetros Densidad del canal de Havers por mm2, Diámetro del canal de Havers y diámetro del sistema Haversiano, los cuales fueron comparados mediante one way ANOVA con Scheffé post test con p<0,05. Posteriormente se construyeron las funciones discriminantes para cada especie y se determinó el porcentaje de casos bien diagnosticados. Se encontraron diferencias significativas en los parámetros analizados, las funciones discriminantes permitieron la correcta clasificación del 88,5 por ciento de los casos. Nuestros resultados sugieren que es posible diferenciar restos óseos humanos de no humanos mediante la observación de sus características histológicas y parámetros histomorfométricos, pero la diferenciación interespecie requiere de análisis más complejo...

Two-dimensional numerical analysis of impact response of the human tibia in Car-pedestrian accidents / 国际生物医学工程杂志

Objective The purpose of this paper was to use a new biphasic poroelastic tibia model to develop a two-dimensional numerical method for simulating impact responses of human tibia in car-pedestrian accidents. Methods The geometry of tibia model was reconstructed from CT scans of the left tibia of a living human volunteer. A poroelastic approach was utilized to establish the governing equations of the model and the finite element method was applied to solve these governing equations. Both cortical and cancellous components of tibia were represented using a poroelastic material model consisting of solid phase (matrix) and fluid phase (marrow). A lateral-medial impact direction was selected in the simulation analysis and the impact responses of the pedestrian tibia during 0-200 ms were analyzed. Results The bending deformation of the tibia predicted by the computer simulation was primarily concentrated on the impact zones. The displacement response of Node 107 in the impact zone indicated a peak displacement of -6 mm at around 75 ms, and the significant time delay between the impact force and the displacement response of the skeleton. The axial stress response at the center of element E77 in the impact zone indicated a peak stress of 140 MPa at around 30 ms,and the significant time delay was observed between the impact force and the axial stress response of the skeleton, too. Conclusion This research developed a two-dimensional numerical method for simulating impact responses of human tibia in car-pedestrian accidents. It was able to approximately simulate the bending deformation, lateral displacement response and axial stress response of pedestrian tibia in the impact zones,and the effects of the fluid phase on the solid phase. More in-depth investigation is helpful to further the biofidelity of tibia dynamics model.

Effect on the enucleation of the intraosseous ameloblastoma

Ameloblastoma is cytologically a benign tumor, but is clinically characterized by infiltrative growth and high recurrency. The criteria for surgical treatment of ameloblastoma has not yet established and it is generally accepted that ameloblastoma be treated differently based on clinical types. The purpose of this paper is to consider effectiveness of enucleation in large-sized intraosseous ameloblastoma that has treated more frequently by radical treatment. 39 cases of the intraosseous ameloblastomas were treated by enucleation in the department of oral and maxillofacial surgery of Yonsei University, dental college from February 1990 to January 2001. 25 cases were selected because they were large in size that could produce facial disfigurement or pathologic fracture of jaws. They were radiographically characterized by the cortical bone that was expanded or eroded locally and histopathologically by 19 solid ameloblastomas and 6 intramural type of unicystic ameloblastomas. Among the 25 cases, 4 cases - 3 solid ameloblastomas and 1 intramural type of ameloblastoma - recurred. Recurrence rate was 16%. The compact bone which is not invaded by ameloblastoma was used as surgical margin of enucleation with accompanying chemical cauterization for killing the residual tumor cells. This may have been the reason for the low recurrence rate. So, it is considered that enucleation and long-term follow-up enable the large-sized intraosseous ameloblastomas that were characterized by almost destroyed cancellous bone and expanded or discontinued cortical bone to treat minimizing facial disfigurement and masticatory dysfunction and sociopsychological impact produced by radical treatment. I recommend that the large-sized intraosseous ameloblastomas without involvement to the surrounding soft tissues be first treated by enucleation.