Life Sciences Commons^™

Conventional And High Resolution Scanning Electron Microscopy Of Biological Sectioned Material, C. Scala, G. Cenacchi, P. Preda, M. Vici, R. P. Apkarian, Gianandrea Pasquinelli

Scanning Microscopy

Intracellular structures of embedded biological tissues (rat kidney, myocardium and small intestine) were observed by conventional-scanning electron microscopy (C-SEM) and high-resolution scanning electron microscopy (HR-SEM) after glass knife sectioning. C-SEM of semi -thin sections of material processed the same way as conventional transmission electron microscopy (TEM) provided strong backscattered electron (BSE)-dependent, two-dimensional secondary electron images (SEI(-)) which precisely integrated and further extended previous light microscopy (LM) observation of the same specimen. In addition, the three-dimensional (3-D) arrangement of intracellular organelles was appreciated using a mixture of acetone-soluble acrylic resin in place of epoxy resin embedding. Since the identification of such …

The Development Of Dendritic Carbides In A Dual-Phase Martensitic/Ferritic Steel, E. Materna-Morris

Scanning Microscopy

Several ferritic-martensitic laboratory melts with a varying chromium content of 9-14 wt.% and delta-ferritic quantities ranging from 0-25% were investigated by means of impact-testing. The negative influence of delta-ferrite (>0.5%) on the mechanical properties can be explained by the formation of dendritic M₂₃C₆-precipitates around the delta-ferrite grains. The development of these dendrites was studied as a function of the cooling kinetics using dilatometric and metallographic measurements and by SEM (scanning electron microscopy) and TEM (transmission electron microscopy) investigations.

Microstructure Of Peanut Seed: A Review, Clyde T. Young, William E. Schadel

Food Structure

Mature peanut seed microstructure of importance to the food industry is examined with regard to: (1) anatomy and cytology of peanut seed; (2) the effects of environment on peanut seed; and (3) the effects of various processing procedures on peanut seed. Current peanut seed microstructure research by the authors is directed toward evaluation of the quality of processed peanuts including using TEM, SEM and LM to evaluate the effects of different times of oven roasting at the same temperature, and a method for evaluating quality of homogenization of broken cell and tissue fragments, protein bodies and starch in stabilized peanut …

Healing Of Prosthetic Arterial Grafts, G. Pasquinelli, A. Freyrie, P. Preda, T. Curti, M. D'Addato, R. Laschi

Scanning Microscopy

Numerous synthetic biomaterials have been developed as vascular substitutes. In vitro, ex vivo and in vivo studies have demonstrated that in animals, selected materials, i.e., Dacron and ePTFE (expanded polytetrafluoroethylene) grafts, are successfully incorporated in both the large and the small caliber host arteries through a process which is generally referred to as graft healing. Morphologically, this process consists of a series of complex events including fibrin deposition and degradation, monocyte-macrophage recruitment and flow-oriented cell-layer generation, this last event being the complete endothelialization of the arterial substitute.

In contrast to experimental animals, the flow surface of synthetic vascular grafts remains …

Preparation Of Cereals And Grain Products For Transmission Electron Microscopy, Donald B. Bechtel

Food Structure

This tutorial specifically addresses the techniques used in the processing of cereals and grain products for various aspects of transmission electron microscopy. Methods covered include sample treatment, chemical and physical fixation, dehydration, embedding, sectioning techniques, immunocytochemistry, enzymatic digestions, carbohydrate localization, and lectin binding. The primary goal is to provide information on the preparation of cereals and cereal-based products for microscopic analysis and to assist the reader in solving technical problems associated with studying cereals or other difficult-to-prepare samples.

Effect Of High-Pressure Homogenization On A Sterilized Infant Formula: Microstructure And Age Gelation, Y. Pouliot, M. Britten, B. Latreille

Food Structure

Age thickening and gelation of an Infant formula was Induced by applying high pressure homogenization prior to in-can sterilization. The Initial viscosity of the preparation increased with Increasing homogenization pressure. Thickening rate upon storage, as monitored by viscosity changes, was also proportional to the pressure applied during homogenization. Optical and electron micrographs of 6 month-old samples showed evidence of aggregation. The effect of dissociating agents on the viscosity and microstructure of these samples suggested a contribution of hydrogen bonds and calcium bridges to the gel integrity. The alteration of the mineral balance of aged samples also Indicated a gel strengthening …

Transmission And Scanning Electron Microscopy Of Peanut (Arachis Hypogaea L. Cv. Florigiant) Cotyledon After Roasting, Clyde T. Young, William E. Schadel

Food Structure

Changes in the microstructure of peanut (Arachis~ L. cv. Florigiant) cotyledon after roasting at a temperature of 160°C for 16 minutes were investigated with transmission and scanning electron microscopy. Thermal modifications were documented with photomicrographs of t he cytoplasmic network , protein bodies, starch grains and cell-to-cell junctions after oven roasting. These thermal modifications include disruption of the cytoplasmic network, distension of protein bodies, decreased stain affinity of starch grains , and disintegration of middle lamellae in some cell-t o-cell junctions.