A scanning electron microscopy study of projectile entry fractures in cortical bone; genesis and microarchitectural features

AbstractThe present paper presents a scanning electron microscope (SEM) analysis of the genesis and microarchitecture of experimentally induced cortical entry fractures in porcine scapulae impacted at velocities ranging from 54 to 897 m/s. SEM observation was conducted on polyurethane replicas cast from negative silicone moulds. Analysis of the sequence of fracture processes operative during projectile impact revealed the presence of ring cracks at the site of impact, confirming that penetration in sandwich bones is achieved by cone crack propagation. Despite impulsive loading, two forms of plastic deformation were identified in the cortical bone surrounding the entry fracture up to a maximum velocity of 871 m/s. Microscopic radial and concentric cracks were associated with projectile impact, and the role of pores and pits as stress concentrators was captured. Possible underlying mechanisms for the observed plastic deformation are described, and the diagnostic utility of SEM analysis is presented.

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Factors influencing adhesive bonding at the bone/implant interface

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100130201 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1114-1115

Author(s):

Julie A. Martini ◽

Robert H. Doremus

Keyword(s):

Electron Microscopy ◽

Adhesive Bonding ◽

Microscopy Study ◽

Electron Microscopy Study ◽

Bone Implant ◽

Factors Influencing ◽

Lr White ◽

Transmission Electron ◽

New Zealand White Rabbits ◽

Scanning Electron

Tracy and Doremus have demonstrated chemical bonding between bone and hydroxylapatite with transmission electron microscopy. Now researchers ponder how to improve upon this bond in turn improving the life expectancy and biocompatibility of implantable orthopedic devices.This report focuses on a study of the- chemical influences on the interfacial integrity and strength. Pure hydroxylapatite (HAP), magnesium doped HAP, strontium doped HAP, bioglass and medical grade titanium cylinders were implanted into the tibial cortices of New Zealand white rabbits. After 12 weeks, the implants were retrieved for a scanning electron microscopy study coupled with energy dispersive spectroscopy.Following sacrifice and careful retrieval, the samples were dehydrated through a graduated series starting with 50% ethanol and continuing through 60, 70, 80, 90, 95, and 100% ethanol over a period of two days. The samples were embedded in LR White. Again a graduated series was used with solutions of 50, 75 and 100% LR White diluted in ethanol.

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Electron microscopy study of shock synthesis of silicides

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100151647 ◽

1993 ◽

Vol 51 ◽

pp. 1162-1163

Author(s):

Kenneth S. Vecchio

Keyword(s):

Shock Wave ◽

Plastic Deformation ◽

Close Contact ◽

Microscopy Study ◽

High Energy ◽

Electron Microscopy Study ◽

Powder Materials ◽

Porous Powder ◽

Wave Effects ◽

Wave Passage

Shock-induced reactions (or shock synthesis) have been studied since the 1960’s but are still poorly understood, partly due to the fact that the reaction kinetics are very fast making experimental analysis of the reaction difficult. Shock synthesis is closely related to combustion synthesis, and occurs in the same systems that undergo exothermic gasless combustion reactions. The thermite reaction (Fe2O3 + 2Al -> 2Fe + Al2O3) is prototypical of this class of reactions. The effects of shock-wave passage through porous (powder) materials are complex, because intense and non-uniform plastic deformation is coupled with the shock-wave effects. Thus, the particle interiors experience primarily the effects of shock waves, while the surfaces undergo intense plastic deformation which can often result in interfacial melting. Shock synthesis of compounds from powders is triggered by the extraordinarily high energy deposition rate at the surfaces of the powders, forcing them in close contact, activating them by introducing defects, and heating them close to or even above their melting temperatures.

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To morphology, ecology and distribution of rare species Sellaphora hustedtii (Krasske) Lange-Bertalot et Werum (Bacillariophyta) from waterbodies of the Gydan Peninsula

Novosti sistematiki nizshikh rastenii ◽

10.31111/nsnr/2014.48.57 ◽

2014 ◽

Vol 48 ◽

pp. 57-65 ◽

Cited By ~ 1

Author(s):

S. I. Genkal ◽

M. I. Jarushina

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

River Basin ◽

Rare Species ◽

Western Siberia ◽

Microscopy Study ◽

Electron Microscopy Study ◽

Diagnostic Features ◽

Scanning Electron Microscopy Study ◽

Scanning Electron

A rare species Sellaphora hustedtii, which is also new for the flora of Russia, has been found in waterbodies of the Messoyakha River basin (south-western part of the Gydan Peninsula, Western Siberia). The scanning electron microscopy study revealed variability of the main quantitative and qualitative diagnostic features of the species (length and width of the valve, number of striae and areolae in 10 μm, shape of the valve and structure of the raphe). New data on the ecology and distribution of the species allowed us to specify its diagnosis.

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