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Special techniques are necessary to study the morphology of complex chitinous structures such as insect mouthparts. Many of the details are beyond the resolution of light microscopy, and the methods of conventional electron microscopy do not include the efficient production of serial sections for reconstruction. Although the scanning electron microscope (SEM) permits detailed observation of 3-dimensional surfaces, it cannot see internal surfaces and under complex folds, nor can it readily show the thickness of solid structures. To study the details of the stylet tips of the bug Rhodnius prolixus (Stål) several techniques were tried. Initially, specimens had been embedded in paraffin wax, sectioned, dewaxed, and prepared for the scanning electron microscope. Because of difficulties in sectioning the hard stylets and poor preservation of fine structure, this method was abandoned in favour of one using thick sections (2 μm) of material embedded in a mixture of Epon and Araldite.

The diffusion of mercury has been studied in high-purity zinc as a function of temperature, using the sectioning technique. The diffusion coefficients as measured in single crystals are given by ${D}_{\mathrm{II}}=(0.056\ifmmode\pm\else\textpm\fi{}0.002)\ifmmode\times\else\texttimes\fi{}\mathrm{exp}[\ensuremath{-}\frac{(19700\ifmmode\pm\else\textpm\fi{}48)}{\mathrm{RT}}]$ ${\mathrm{cm}}^{2}$/sec, and ${D}_{\ensuremath{\perp}}=(0.073\ifmmode\pm\else\textpm\fi{}0.006)\mathrm{exp}[\ensuremath{-}\frac{(20180\ifmmode\pm\else\textpm\fi{}94)}{\mathrm{RT}}]$ ${\mathrm{cm}}^{2}$/sec, where ${D}_{\mathrm{II}}$ and ${D}_{\ensuremath{\perp}}$ are the diffusion coefficients parallel and perpendicular to the hexagonal axis, respectively. Compared to the diffusion of cadmium in zinc, where ${D}_{\ensuremath{\perp}}g{D}_{\mathrm{II}}$, mercury diffuses with a slightly smaller activation energy, and with ${D}_{\mathrm{II}}g{D}_{\ensuremath{\perp}}$. The results are discussed on the basis of the basal and nonbasal vacancy mechanisms, and the influence of the ion size of the diffusing atom is examined to explain the diffusion anisotropy.

A technique has been developed for sectioning small gallium arsenide samples utilizing anodic oxidation and subsequent removal of the oxide layers. It differs from those previously reported in that only one surface of the wafer is exposed during anodization and total immersion in the electrolyte is not required. The use of an ammonium pentaborate solution as the electrolyte and a relatively simple anodization apparatus has yielded oxide layers of uniform thickness on the surfaces of gallium arsenide wafers. After removing the oxide layers, the surfaces of the wafers were found to be relatively free of pitting and macroscopic defects.

A dye-staining and sectioning technique has been developed which permits, for the first time, a direct, visual determination of the location of melamine resin in treated wool fibers. The resin appears to be distributed uniformly within the fiber structure. Techniques are described and the results are illustrated by photomicrographs (one in color).

Electron microscopic studies of thin sections of industrial carbons have been extended to green mixes. Pitch is shown to have discrete spherical bodies (0.5–1.0 μ) distributed in a continuous medium. A dissolution technique is described which distinguishes the coke from the binder in a green mix. The results suggest that the coke particles have an irregular three-dimensional porous structure and the apparent inability to observe particles larger than a few microns is explained. The sectioning technique leads to morphological features comparable to those seen by replication.

The fine structural arrangement of the nerve endings on the guinea pig outer hair cells (OHCs) was studied by a serial sectioning technique by means of a high-voltage electron microscope and computer-graphic three-dimensional reconstruction. Sixty-nine series of consecutive sections were observed. Fifteen OHCs were located about 0.5 mm from the basal end (hook portion of basal turn) and 4 OHCs were seen at 6.0 mm, 20 OHCs at 8.0 mm (basal turn), 13 at 12.8 mm (second turn), 8 at 14.8 mm, 7 OHCs at 15.9 mm (third turn), and 2 OHCs at 17.5 mm (apical turn). Of 69 OHCs, 31 cells were from the first row, 22 from the second and 16 from the third row. The total number of nerve terminals on each OHC varied between 5 and 36. The OHCs with the least number of terminals were found in the hook portion, while the OHCs with the most numerous innervation were observed in the third row of the upper third turn. The afferent/efferent ratio (A/E ratio) of each OHC was evaluated and the OHCs were divided into two groups: Type A and Type B, depending upon the range of the A/E ratio. Thirty-five OHCs (50.7%) out of 69 were identified as being type A with an A/E ratio range of 0.5-1.5, while the remaining 34 OHCs (49.3%) were Type B cells with a greater A/E ratio than Type A cells. The detailed distribution of both types of cells was also studied along the entire length of the basilar membrane.

SummaryA contouring device for measuring the face (Cobb, 1972) was adopted and developed to make it suitable for use with children.Modifications were made to overcome incomplete facial coverage and lack of common head orientation by incorporating a method of optical head positioning which had been invented during the assessment of a stereophotogrammetric technique (Ainsworth and Joseph 1976).The precise alignment of a series of exposures with a common datum enables a set of contour maps to be processed by computer to produce three-dimensional measurements and sections of the complete face.

We have developed a method useful for immunohistochemical studies by combining tissue fixation with buffered neutral formalin and polyester wax embedding. Buffered neutral formalin fixation preserves cell and tissue fine structure, and also the antigenicity of unstable enzymes. Polyester wax embedding makes possible thin serial sections of various tissues and preserves antigenicities for at least 6 months. We have demonstrated using this technique the localization of alpha-amylase in mouse salivary gland, parietal-cell specific antigen in mouse glandular stomach, and DNA polymerase alpha and beta in chick tissue.

Hydrogen assisted crack growth was examined in cyclically hardened and notched Ni-single crystals. Tests were performed in different aqueous electrolytes at cathodic potentials as well as in hydrogen gas at different pressures and temperatures. Comparisons between the crack growth rates in alkaline and acid solutions and in hydrogen gas yielded estimates of the effective hydrogen activity at the crack tip for various overpotentials. A new sectioning technique involving so-called micro-milling was used for detailed fractographic examinations. These examinations show that the cracks in Ni-single crystals {orientation: specimen axis [100], surfaces: (110)} grow in hydrogen by a mixture of slip along (111) and local brittle fracture along (100). A simple trapping model is presented which assumes that a high density of deep traps with an apparent binding energy of 32 kJ/mol H is produced at the crack tip within a zone of less than 10 nm during crack growth. This model describes the pressure, temperature and frequency dependence of the crack growth rate, da/d, N, without any additional fitting parameters.

The metallurgy of the surface and sub-surface regions of a centreless ground hardened and tempered EN 24 steel has been investigated. Surfaces examined showed ductile wear tracks, evidence of local melting, the presence of redeposited fragments and “grinding spheroids”. Sections of the ground surface were viewed by means of a taper sectioning technique. A white layer (W.L.) with a hardness of 650 HV was formed at the surface. The mean thickness of the white layer varied from 0.6 μm to 0.3 μm. Below the white layer was a much thicker softer zone with a hardness of 430 HV, the bulk hardness was 500 HV. Using a transmission microscope at a magnification of up to 104 a preliminary examination of the white layer showed it to consist of extremely fine grained material. Heat treatment of the white layer has been studied.

Uteri from four patients with endometrial adenocarcinoma and concomitant “functioning” endometrium were examined by a whole-organ sectioning technique. All showed one or several “progesterone-refractory” mucosal areas or polyps, mainly in the tubal recesses. In one patient the adenocarcinoma obviously originated in a fundal polyp, and in the others the tumors could have arisen in mucosal areas not adequately responding to progesterone. These findings do not in fact contradict the “unopposed estrogen” theory of the genesis of endometrial carcinoma.

We describe an apparatus which allows us to measure accurately the self-diffusion coefficients by the standard thin film deposition and sectioning technique. The accuracy of each measurement of the self-diffusion coefficient is about 0,4%. This accuracy allows a positive curvature to be detected in the β−Tl Arrhenius plot. The possibility that this effect be due to preferential diffusion along grain boundaries is discussed. We conclude that the observed curvature reflects the properties of the β−Tl monocristal. Two supplementary experiments allowed us, on the one hand to define satisfactory experimental conditions for the electro-deposition of thallium from a thallous sulphate solution and, on the other hand, to measure accurately the α−β transition temperature of thallium, that is found to be 235,25±0,1°C Nous presentons un ensemble experimental permettant la mesure precise de coefficients d'autodiffusion par la technique du depot mince et du sectionnement. La precision moyenne atteinte sur la mesure du coefficient de diffusion est de 0,4%. Cette precision permet de detecter une courbure positive dans le graphe d'Arrhenius de β-Tl. La possibilite qu'il s'agisse d'un effet de diffusion preferentielle dans les points de grains est discutee. On conclut que la courbure observee reflete les proprietes du monocristal. Deux experiences annexes nous ont permis, d'une part de definir des conditions experimentales satisfaisantes pour le depot electrolytique du thallium en solution sulfurique, et, d'autre part, de mesurer avec precision la temperature de la transition α−β du thallium, soit 235,25±0,1°C.

Food preferences and feeding behaviour of abundant species of oribatid mites in a black pine plantation have been studied by soil sectioning technique. It is suggested that Microtritia minima, Rhysotritia duplicata and Phthiracarus sp. play an important role in the mechanical breakdown of decaying litter and, by contributing to the humification process, help in the accumulation of plant nutrients. Due to poor mobility their contribution to fungal spore dissemination is insignificant. Chamobates incisus was determined to be a fungivorous species while no exact information could be obtained about the precise food of Tectocepheus velatus. Rest of the species seemed to consume large quantities of decaying litter but in view of their low populations throughout, presumably they do not contribute appreciably in the humification process.The speed of decomposition of faecal pellets seemed to be governed by the type of food ingested. The role of oribatid fauna in the litter and soil ecosystems is discussed.

The fluorescence technique has been applied to whole body tape sections to study the distribution of 6 commercially available tetracyclines. The tape sectioning technique described by Ullberg for autoradiography of labeled chemical compounds has proved to be of value also in distribution studies of fluorophors. The distribution patterns of the tetracycline compounds have been studied as well as the influence of different routes of administration. The fluorescence distribution picture of tetracycline has been compared to the autoradiogram of the radioactively labeled compound. The influence of pH on the fluorescence has been investigated. Advantages and limitations of the method are discussed.

A tracer sectioning technique was employed to measure cation self-diffusion coefficients in fully dense polycrystalline materials under oxidizing conditions. Results are D = 1.65x10/sup -2/ exp(-69,200/RT) cm/sup 2//s for Y/sub 2/O/sub 3/ (1400 to 1670/sup 0/C), and D = 1.48 exp(-102,200/RT) cm/sup 2//s for Er/sub 2/O/sub 3/ (1400 to 1700/sup 0/C). The greater activation energy for erbium diffusion in erbia is attributed to a mass effect. Oxygen diffusion coefficients were extracted from observations in the reoxidation of small single crystals of uniformly reduced oxides produced by vacuum fusion. The oxidation process proceeded by the development of a fully oxidized external shell, the growth of which was rate-limited by diffusion of interstitially dissolved oxygen through the oxidized layer to a sharp interface with the reduced material. The growth of the oxidized shell was followed by means of a thermobalance. Oxygen diffusion coefficients were calculated to be D = 6.01x10/sup -6/ exp(-19,600/RT) cm/sup 2//s for Y/sub 2/O/sub 3/ (1064 to 1276/sup 0/C), and by D = 4.76x10/sup -5/ exp(-30,100/RT) cm/sup 2//s for Er/sub 2/O/sub 3/ (1060 to 1292/sup 0/C).

We describe a technique for preparing 100-1 50 micron thick sections of bone plus metal implant that have been embedded in polymethyl methacrylate (PPM). Sectioning was done with a low speed saw, and PMM was removed with a xylene and eosin solution (80:20 V:V). Sections were fixed on glass slides using Eukitt's mounting medium. Bone-metal specimens prepared in this manner allow optimal visualization of the bone implant interface and microscopic assessment of soft and hard tissues for histomorphometry.

Alternating translucent and opaque bands on the roots of mammal teeth are used to determine the age and season of death. These structures are preserved in teeth from archeological sites. However, the standard sectioning technique, which includes decalcification, often destroys archeological specimens. A new, less destructive technique provides analyzable solid sections at costs comparable to decalcification.

Submicron sectioning apparatus for studying slow carbon self diffusion in dense polycrystalline tungsten carbide

The self-diffusion of single crystal thallium has been measured from 150°C to 275°C with the use of Tl204 as a tracer and the standard sectioning technique. For diffusion parallel to the c-axis the data were well fitted by an activation energy of Q = 22.9 kcal/mol and a D0 = 0.4 cm2/sec, and for diffusion perpendicular to the c-axis 0 = 22.6 kcal/mol and D0 = 0.4 cm2/sec. The cubic phase was investigated also and resulted in the values Q = 20.0 kcal/mol and D0 of order 0.7 cm2/sec. Possible mechanisms are discussed.

A recent development, scanning electron microscopy, makes possible, with its high magnification (×100 to ×100 000) and great depth of focus (300 times greater than optical microscopes), three‐dimensional investigation of the structure of the cochlea. In our preliminary study, fresh guinea pig cochleae were fixed by several different methods. The fixed cochleae were frozen and surface specimens of the organ of Corti were prepared by “planing” with a microtome. [G. J. Jako, Frozen Sectioning Technique for Studying Distribution of Dyes and Isotopes in Guinea Pig Cochleae, abstract, Intl. Congr. Biophys., 1st (1961)]. The specimens were then dehydrated and coated with a thin, 500‐A thick, gold film in a vacuum evaporator. The details of specimen preparation and the interpretation of the results will be discussed.

Using a rapid freezing and sectioning technique, the distance between the lens and retina of the horse eye was measured. There is no indication of a ramp retina that could serve accommodation. The pupil axis of the eye coincides with the maximum lens to retina distance. The changes in the lens-retina distance are greater below the axis than above it. Calculations were made of refractive power of the horse eye from measurements of curvature and refractive indices of the ocular tissues. These calculations agree both qualitatively and quantitatively with retinoscopic measurements on live horses. Both show that the refractive state shifts in the direction of hyperopia above and below the axis and that this shift is greater below the axis than above it. Some dynamic accommodative ability in the living eye was observed.

Diffusion of 54 Mn in Mn 1−δ O single crystals has been measured by a serial sectioning technique as a function of temperature (1000–1500°C) and deviation from stoichiometry (0.00003 m in the expression D = D 0 (T)p O 2 1 m varies from about 6 at low P o 2 at all temperatures to a value approacing 2 at high P o 2 and high temperatures, thus suggesting that diffusion occurs by doubly charged vacancies at low P o 2 with increasing contributions from singly charged and neutral vacancies as P o 2 (and vacancy concentration) increases. For δ near 0.1, the values of D fall below the values extrapolated from smaller defect concentrations. The isotope effect for cation self-diffusion was measured by simultaneous diffusion of 52 Mn and 54 Mn in Mn 1−δ O (0.0004 f ΔK are independent of temperature within experimental error, and decrease from a value of 0.70 at low defect concentrations to 0.37 for large values of δ. The isotope-effect results suggest that diffusion occurs by single non-interacting vacancies at low defect concentrations; defect-defect interactions become important for δ ≳ 0.01. The defect-defect interactions may involve essentially individual defects or may result in defect clusters; the similarity between the present isotope-effect results and those for Fe 1−δ 0 suggests that defect clustering plays a significant role in mass transport in Mn 1−δ O at large values of δ.

A novel gel sectioning technique has been devised for the assessment of self-diffusion coefficients in organic liquids. Its application to benzene and cyclohexane yields results for both diffusion coefficients and their temperature-dependence which are in excellent agreement with values obtained with the conventional diaphragm cell technique.

An investigation is made of the error due to truncated impulse response for the block mode or sectioning technique. The upper bound on the error in terms of the sectioning parameters is obtained and shown to be independent of block size; this results in a simpler approach to obtaining an optimal sectioning procedure.

The Armed Forces Institute of Pathology has long provided the best bargain in medical publications for profusely illustrated atlases. This is no exception. For complete success, two additional ingredients are needed—good tissue sections and high-quality illustrations of them. Dr. Tucker has provided uniformly excellent total organ sections through the larynx at 1-mm intervals. The anatomical landmarks are clearly labelled. This atlas should be of considerable help to otolaryngologists (especially residents) and pathologists who wish to visualize subgross relationships. This is the stated aim of the atlas, and it is well fulfilled. One cannot help but hope that someday a companion atlas will be produced detailing the lymphatics of the larynx utilizing the same sectioning technique. My criticisms are few. There is a lack of economy in the 3½ pages showing virtually identical high-power views of sympathetic ganglia, two full pages of which are the same ganglion at different levels of