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This paper addresses a current debate about the morphology of M7C3 phase in the chrome carbide overlay (CCO) and white iron community. This morphology was investigated using a serial sectioning technique in combination with computer post-processing software. A 600×600×300 μm volume of CCO was reconstructed in three dimensions (3D) to determine the difference between blade and rod-like carbide morphologies. The 3D analysis revealed that the two carbides morphologies correspond to the same hexagonal rod-like structures, but are oriented in different directions relative to the sectioning plane.

‘Chatter’ is a histologic artifact which can obscure morphology, sometimes precluding histopathologic diagnosis. Chatter in gastrointestinal (GI) biopsies is a particular challenge in many laboratories. This departmental quality assurance initiative sought to determine (1) the prevalence of chatter in GI biopsies, (2) its relationship to histotechnologist, section level and anatomic site, and (3) the effectiveness of education and technical adjustments in reducing its rate. A gastrointestinal pathologist evaluated 660 randomly selected slides for chatter artifact. Biopsy site, level (slide 1,2 or 3) and sectioning histotechnologist were recorded. Histotechnologists completed a questionaire on block handling and sectioning technique. The study was repeated 6 months following feedback and implementation of technical measures to reduce chatter. Moderate-to-severe chatter was present in 9.2% of slides (61/660), with wide variation between the 11 histotechnologists (range 0-19%). All four histotechnolo...

The variation in the position of antipodal cells before and after fertilization in polyembryonic rice strain Ap III was studied by using conventional sectioning technique. It was shown that initially the three antipodal cells lie at the chalazal end of the young embryo sacs. Along with the development of embryo sac, the antipodal cells proliferate into a multicellular structure containing up to about 20 cells. Most of the cellsmigrate to its dorsal side when the embryo sacs turn into mature. In a few embryo sacs the antipodal cells are situated in the positions adjacent to the egg apparatus at the micropylar end, while in other sacs, they spread from the midst of the embryo sac to the micropylar end clinging to the nucellar tissue. Furthermore, it is reported for the first time that cells of some egg apparatus or proembryos disorganize when antipodal cells lie at the micropylar end, indicating that the function of the antipodal cells may vary during the embryogenesis in rice Ap III.

Ultrathin sectioning, one of the types of specimen preparations for transmission electron microscopy (TEM), has been considered the most perfect sectioning technique leading to the thinnest sections (50–100 nm). Following a study based on a newly developed low-voltage TEM technique, a relief on the ultrathin sections of polymer blends was observed that was ascribed to substantial differences in mechanical properties of the blend constituents.[1] In this study, an analogous relief was observed with a blend, the constituents of which are both hard in cutting. The origin of the surface relief on ultrathin sections of polymer blends was sought using low-voltage scanning TEM and atomic force microscopy. Polycarbonate/styrene-co-acrylonitrile blend was examined as a representative of blends with all components well under T g at room temperature. A distinct surface relief was observed on both ultrathin sections and remaining cut surfaces of the blend for low-temperature and room-temperature cutting. A rougher su...

Grain-boundary impurity diffusion of Au along the incoherent twin boundary in a diffusion-bonded Cu bicrystal has been studied by the serial sectioning technique. The measured penetration profiles had a rather atypical shape which we interpreted in terms of structural multiplicity of the grain-boundary structure. A method of processing such profiles has been suggested and the relative fraction of the grain-boundary structural modification exhibiting the lowest diffusion coefficient has been estimated as 60% . The difference between the energies of the two structural modifications has been estimated as being less than 17%, which is in good agreement with the results of computer simulations of the grain-boundary energy in Cu.

The discontinuous solid state reactions represent a group of diffusional solid state phase transformations during which the solute redistribution accompanying the formation of a new phase occurs on a nanometer scale just at the moving reaction front. Such solute changes can be sufficiently revealed by means of analytical electron microscopy (AEM). A number of systematic investigations made using AEM during the last decade in discontinuous precipitation, dissolution, and coarsening are reviewed and critically analysed. Measurements of the solute concentration profiles in the direction parallel to the reaction front are strongly emphasised, as they allow verification of theoretical models of discontinuous reactions and consideration of discontinuous reactions as local phenomena in the form of a number of events occurring in individual cells. Such an attempt removes the divergence between the tracer diffusivity values obtained by the sectioning technique and the chemical diffusivity data obtained fro...

The diffusion of Fe and Ge in the D03 phase Fe3Si has been studied as a function of temperature and composition using a tracer sectioning technique and the radioisotopes 59Fe and 71Ge. One experiment with the short-lived 31Si radiotracer was carried out to examine the similarity of Ge diffusion and Si diffusion. These elements diffuse with similar rates. The results are discussed considering composition dependences, magnetic and ordering transitions. The most striking fact is that Fe diffusion in the D03 structure Fe3Si is much faster and the corresponding activation enthalpy is considerably lower than in bcc Fe or in disordered Fe-rich Fe-Si alloys. By contrast, diffusion of Ge and Si is a great deal slower and the activation enthalpy is higher than in the disordered phases. While Fe diffusion is strongly dependent on the alloy composition, diffusion of Ge in Fe3Si is less affected by the Si content. Possible diffusion mechanisms are discussed in the light of additional information on Fe3Si. The...

Measurements of Co diffusion in α-Ti were made by using radiotracers and the direct sectioning technique. The Arrhenius plot obtained is a straight line for the whole range of temperature covered (619–823 K) with Q = 127 ± 6 kJ mol−1 and D o = (3 ± 1)× 10−6m2s−1. The results show an excellent agreement with previous ones in the range (871–1135 K) and they suggest that there is no ultrafast impurity influence in the diffusion in the α-Ti matrix.

The diffusion of 59Fe in Incoloy 800 has been studied using the serial sectioning technique in the temperature ranges 1020–1500 K for volume diffusion and 750–1100 K for grain boundary diffusion, respectively. The volume diffusion coefficients can be represented by the expression: D(1020–1500 K)=3·26×10−5 exp (−259·6 kJ mol−1/RT) m2 s−l. The grain boundary diffusion coefficients were evaluated in most of the experiments using Whipple's method. For afew specimens, Suzuoka's method was applied. The penetration depths beyond which these methods were to be applied to analyse the experimental results were determined both graphically and by extensive use of autoradiographic techniques. The grain boundary diffusivities can be expressed as: Dgb (750–1100 K)=1·88×10−5 exp (−160·7 kJ mol−1/RT) m2 s−1, The results are discussed and presented in this paper.MST/l193

In a series of 80 consecutive mastectomies it was investigated histologically, by a horizontal sectioning technique, how often the nipple and/or areola were involved in breast cancer. Such involvement was found in 35 cases (43.8%). In the same series the value of the clinical findings as to involvement of the nipple and/or areola was assessed. Only 6 of the 35 cases had shown clinical changes that could give rise to a suspicion of spread to the nipple and/or areola.

Self-diffusion of 35S labelled molecules in highly perfect single crystals of orthorhombic sulphur has been studied by the serial sectioning technique. Measured lattice self-diffusion coefficients are considerably lower than those previously published for this solid. This difference is believed to be a consequence of a significant contribution from diffusion along dislocations in the crystals used in the previous study. Self-diffusion perpendicular to the [001] direction can be represented by an equation of the form D=2 × 1013exp[-(215±11 kJmol−1)/RT]m2s−1. Self-diffusion coefficients in the [001] direction are 2–4 times lower. This distinct anisotropy is probably a consequence of the marked structural anisotropy of this phase of sulphur.

An inexpensive and simple technique is described to collect and section undisturbed core samples of wetland rice soil that can be used for research.

The microanatomy of vagal body paraganglia (VBP) in the cephalic segment of both vagus nerves was evaluated in an autopsy study of 32 infants one year of age or younger. The study group included 14 victims of sudden infant death syndrome (SIDS) and 18 non-SIDS cases. VBP in both groups were located at or below the lower border of the ganglion nodosum, and were histologically identical to carotid body chemoreceptors, although spatially dispersed and much smaller in size. Using a combined step and serial sectioning technique, there were no significant differences between the two groups (i.e. SIDS vs. non-SIDS) with regard to microanatomy, number, distribution and size of VBP. The proportion of chief and sustentacular cells was similar to carotid body paraganglia. For the study group as a whole, VBP were present in 89% of vagus nerves, and were typically multiple with good correlation between the number of separate paraganglia on the two sides. Small collections of ectopic parathyroid chief cells were identified in 6% of nerve segments, and histologically should be distinguished from VBP. Although the microanatomy of VBP in the SIDS group was identical to that of non-SIDS, one cannot exclude an underlying functional abnormality with autonomic malregulation.

Abstract The thin layer lathe sectioning technique was used to measure the self and solute diffusion coefficients of gold in f.c.c. lanthanum. Self-diffusion is given by D = 1.5 exp (− 45100/RT) cm2/sec, and gold solute diffusion by D = 2.2 × 10−2 exp (− 18100/RT) cm2/sec. The activation energy for self-diffusion is in good agreement with various semi-empirical rules. The high diffusivities and low activation energy for the solute diffusion of gold are interpreted in terms of the combined substitutional–interstitial diffusion mechanism.

Self diffusion of 48V in vanadium single crystals was reinvestigated over the temperature range 724–1842°C. Contribution to diffusion from migration along short-circuit paths at the lower temperatures was avoided by applying a micro sectioning technique specially developed for this study. The change in slope of the Arrhenius curve reported to occur at about 1350°C was not observed in this investigation, but has been observed to occur in the vicinity of 1642°C. The data in the temperature range 724–1642°C can be fitted to the relation consistent with normal diffusion by a single-vacancy mechanism. Above 1642°C the data fit the equation

The diffusion of mercury at very low concentration in single crystal gold has been measured over the temperature range 500°C to approximately 1000°C using a sectioning technique. It was found that above 600°C the temperature dependence of the diffusion coefficient followed the equation: The results obtained are discussed in relation to current theories of impurity diffusion in metals.

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.