Sample preparation and imaging techniques for scanning electron microscopy (SEM) of dehydrated dental samples can hinder the structural analyses. This study qualitatively evaluated images obtained with two different protocols of SEM preparation and analysis to assess the dentine adhesive interface. The crown and root dentine of 12 bovine incisors were subjected to cementation with the resin cement RelyX U100 or RelyX ARC/SBMP (n = 6). After storage for 7 days in a moist environment at 37 ± 1°C, the dentine samples were dehydrated in an ascending alcohol series, and three specimens from each group were coated with gold or carbon and examined in a high-vacuum (JEOL JSM—6360LV, 10 kV) or low-vacuum (FEI Quanta 200F, 15–30 kV) microscope. Images were obtained at magnifications between 50 and 2,000×, but with different working distances. The use of high vacuum for carbon and gold coating and SEM visualization led to cracks in the samples. A small number of cracks can be described in the specimens subjected to the low-vacuum technique. The protocol for SEM imaging in low vacuum was considered more appropriate for preservation of the integrity of the evaluated structures.

Nous avons évalué l’intérêt des gants de radioprotectionde radiologie interventionnelle pour de la manipulation de radionucléidesdans un service de médecine nucléaire. Des mesures d’atténuationfaites par des dosimètres thermo-luminescents placés à l’intérieurde gants au contact des flacons ont montré une augmentation significativede la dose aux extrémités dans le cas d’un émetteur γ, et une réductionde dose pour un émetteur β. Des mesures complémentaires faites aumoyen d’un irradiateur X (150 kV) ont montré qu’il existe une productiond’électrons secondaires dans le gant, dont le parcours dans l’airest estimé à 6 cm. Étant donné que l’utilisation d’un gant radio-atténuateurdans une boîte à gants de médecine nucléaire doit être compatibleavec l’ensemble des radionucléides utilisés, notre équipe n’utiliserapas de tels gants dans la pratique quotidienne.

The use of 75Selenomethionine labelled cercariae of Schistosoma mansoni for ultrastructural localization of parasites in host tissues has been evaluated. Both gamma counting of tissue, and autoradiography of resin-embedded tissue were successful. The autoradiographic technique was more sensitive and schistosomula were readily located in pulmonary tissue up to 24 days post-infection.

Spectrum simulation is a useful practical and pedagogical tool. Particularly with complex samples or trace constituents, a simulation can help to understand the limits of the technique and the instrument parameters for the optimal measurement. DTSA-II, software for electron probe microanalysis, provides both easy to use and flexible tools for simulating common and less common sample geometries and materials. Analytical models based on ϕ(ρz) curves provide quick simulations of simple samples. Monte Carlo models based on electron and X-ray transport provide more sophisticated models of arbitrarily complex samples. DTSA-II provides a broad range of simulation tools in a framework with many different interchangeable physical models. In addition, DTSA-II provides tools for visualizing, comparing, manipulating, and quantifying simulated and measured spectra.

Kinematical and two-beam calculations have been conducted and are compared to experimental precession data for the large unit cell crystal La4Cu3MoO12. Precession electron diffraction intensities are found to exhibit approximate two-beam behavior and demonstrate clear advantages over conventional SADP intensities for use in structure solution.

One approach being explored as a route to practical fusion energy uses heavy ion beams focused on an indirect drive target. Such beams will lose electrons while passing through background gas in the target chamber, and therefore it is necessary to assess the rate at which the charge state of the incident beam evolves on the way to the target. Accelerators designed primarily for nuclear physics or high energy physics experiments utilize ion sources that generate highly stripped ions in order to achieve high energies economically. As a result, accelerators capable of producing heavy ion beams of 10 to 40 MeV/amu with charge state 1 currently do not exist. Hence, the stripping cross sections used to model the performance of heavy ion fusion driver beams have, up to now, been based on theoretical calculations. We have investigated experimentally the stripping of 3.4 MeV/amu Kr+7 and Xe+11 in N2; 10.2 MeV/amu Ar+6 in He, N2, Ar, and Xe; 19 MeV/amu Ar+8 in He, N2, Ar, and Xe; 30 MeV He+1 in He, N2, Ar, and Xe; and 38 MeV/amu N+6 in He, N2, Ar, and Xe. The results of these measurements are compared with the theoretical calculations to assess their applicability over a wide range of parameters.

The aim of this study was to analyse the tissue surrounding prematurely extruded ventilation tubes (grommets). Thirty-one ventilation tubes, including 21 Shah and six Shepherd tubes, that had been extruded naturally into the ear canal were examined. After formalin fixation, material adhering to the tubes was retrieved and processed to paraffin wax. Five tubes were processed for scanning electron microscope (SEM) analysis. Sections were stained using histochemical methods for collagen, keratin and keratohyaline. In addition, the presence of collagen (type I and III), keratin, vimentin, fibronectin, tenascin, factor VIII-related antigen, CD31 and CD45 was tested for by immunohistochemistry. Results showed that all specimens consisted of an acellular fibrous material, oriented in concentric rings parallel to the tube surface that was often associated with small collections of CD45+ inflammatory cells. Two specimens contained collagen that was detectable by histochemical and immunohistological methods. Twelve specimens contained identifiable desquamated epithelial cells containing keratin and keratohyaline. Only one specimen stained positively for connective tissue markers (vimentin, fibrous fibronectin, tenascin) or showed the presence of vascular epithelium. SEM revealed adherent clusters or sheets of plate-like structures, consistent with the presence of epithelial squames, on three of the five ventilation tubes examined. It is concluded that tissue retained on extruded grommets consists of orthokeratinitizing epithelium infiltrated by inflammatory cells, a finding that is consistent with the theory that tube extrusion occurs as a result of squamous epithelial proliferation, medial migration, differentiation and desquamation. epithelial cells containing keratin and keratohyaline. Only one specimen stained positively for connective tissue markers (vimentin, fibrous fibronectin, tenascin) or showed the presence of vascular epithelium. SEM revealed adherent clusters or sheets of plate-like structures, consistent with the presence of epithelial squames, on three of the five ventilation tubes examined. It is concluded that issue retained on extruded grommets consists of orthokeratinitizing epithelium infiltrated by inflammatory cells, a finding that is consistent with the theory that tube extrusion occurs as a result of squamos epithelial proliferation, medial migration, differentiation and desquamation.

A case of paraganglioma arising within a parathyroid gland is reported. The lesion was an incidental finding in a block dissection of neck performed for squamous carcinoma of the pharynx. A well-circumscribed lesion, exhibiting the characteristic pathological features of a paraganglioma, was embedded within the right inferior parathyroid gland. Due to its location, the chief histological differential diagnosis was an unusual variant of parathyroid adenoma. Immunohistochemistry and electron microscopy assisted in reaching a diagnosis. This, as far as we are aware, is the first reported case of a paraganglioma of the parathyroid gland.

This is the first report of the application of a new examination technique for the assessment of cellular activity during bone resorption in chronic suppurative otitis media (CSOM). A total of nineteen incudes removed during the course of tympanomastoid surgery were studied (retraction pocket: 2; tubo-tympanic CSOM: 4; attico-antral CSOM: 13). The microscopic surface topography of each specimen was examined using the scanning electron microscopy (SEM), and the appearances are interpreted in terms of cortical cellular activity. The results suggest that the mechanism of ossicular erosion in CSOM is similar regardless of the exact type of disease. Extensively, pitted areas were seen in all specimens. These pits are morphologically indistinguishable from those characteristic of osteoclastic activity (Howship's lacunae). We conclude that in all causes the surface topography of eroded incudes is consistent with the activity of osteoclasts.

A four-year study was undertaken to determine the value of electron microscopy in the diagnosis of head and neck tumours. During this period 80 samples were submitted for examination, of which 69 contained assessable tumour. Electron microscopy made a major contribution to the diagnosis in 25 cases (36 per cent). Areas in which ultrastructural examination was of diagnostic significance included the precise categorization of apparently undifferentiated carcinoma and the identification of melanomas. Little diagnostic benefit was gained from electron microscopic examination of thyroid, lymphoid or salivary gland neoplasms. The value of electron microscopy in relation to immunohistochemistry is discussed.