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The aim of this study was to introduce a method to evaluate the risk of inferior alveolar nerve (IAN) injury following the extraction of impacted lower third molars. Two hundred impacted lower third molars adjacent to the IAN were evaluated. These were divided into four classification groups according to preoperative cone beam computed tomography (CBCT) findings: AR, apical region; LT, lateral region of the tapered root; LE, lateral region of the enlarged root; AE, adjacent to the enlarged root. All teeth were dislocated along the long axis or arc of the root by tooth sectioning technique and extracted by a single surgeon. The primary outcome variable was postoperative neurosensory impairment of the IAN. The χ2 test was used to evaluate differences in postoperative IAN injury between the classifications. Logistic regression analysis was used to evaluate the risk factors for postoperative IAN injury. The overall incidence of postoperative IAN injury was 7%. Specifically, most injuries involved classification AE (AE 36%, LE 8.6%, LT 3.6%, AR 0%), and the difference was statistically significant (P< 0.05). Logistic regression showed that classification AE was the only risk factor for postoperative IAN injury (P< 0.001). According to preoperative CBCT, the risk of postoperative IAN injury is higher when the IAN is adjacent to the enlarged part of the root.

The function of the hippocampus depends on the process of adult hippocampal neurogenesis which underpins the exceptional neural plasticity of this structure, and is also frequently affected in CNS pathologies. Thus, manipulation of this process represents an important therapeutic goal. To identify potential strategies, organotypic adult brain slices are emerging as a valuable tool. Over the recent years, this methodology has been refined and here we present a combined protocol that brings together these refinements to enable long-term culture of adult hippocampal slices. We employ a sectioning technique that retains essential afferent inputs onto the hippocampus as well as serum-free culture conditions, so allowing an extended culture period. To sustain the neurogenic potential in the slices, we utilize the gliogenesis-inhibitor Indomethacin. Using EdU retention analysis enables us to assess the effects of pharmacological intervention on neurogenesis. With these improvements, we have established an easy and reliable method to study the effects of small molecules/drugs on proliferation and neuron formation ex vivo which will facilitate future discovery driven drug screenings.

Cross-sectioning plays an important role in failure analysis. However, commonly used polishing method affects the bonded silicon microchannels and face-to-face interlaced carbon nanotubes (CNTs). Polishing damages the edge of the microchannels and the debris from polishing may be trapped in the microchannels. This paper proposes a novel cross-sectioning technique to realize precise cross-sectioning while maintaining the integrity of bonded silicon microchannels and face-to-face interlaced CNTs. Result shows intact cross-sectioning of the microchannels and CNTs inside.

This study was aimed to highlight the individual effects of melatonin (MEL) and hyaluronic acid (HA) on bone healing and repair mechanism and to investigate a possible effect, for a topical application. New Zealand rabbits used in this study were divided into three groups for two healing intervals the experimental groups were: 1. Experimental groups (20 rabbits): all animals subjected to surgical operation in right tibia, creating bone defect 3mm in depth and 4mm in diameter filled with 0.1ml. Hyaluronic acid gel and left tibia bone defect filled with melatonin gel. 2. Control group (10 rabbits): induced bone defect on the right side only. Animals’ scarifications were done in 2 weeks and 4 weeks’ durations. Routine processing and sectioning technique was performed for histological evaluation. At the 2weeks healing interval, highest mean value of all measured parameters were recorded at melatonin group while at 4 weeks, there is high significant difference in all parameters; (p-value 0.000) among all control and experimental groups. A significant number of positive effects of MEL, as well as HA, as individual compounds on the bone healing regeneration.

Background Pathology reports of basal cell carcinoma (BCC) biopsies often contain comments of positive or negative margins, with only 1%-2% of the margin evaluated. The negative predictive value (NPV) of biopsy margin status on residual BCC is unknown. Objective The purpose of this study was to determine the NPV of BCC biopsy margin status on the absence of residual BCC in the corresponding excision. Methods From our institution's archives, we collected BCC biopsies with negative margin readings that had subsequent excisions. For excisions read as negative for residual BCC, the excision blocks were sectioned at 150-μm intervals until exhausted. Results We collected 143 cases that met criteria; 34 (24%) were found to contain residual BCC in the corresponding excision leading to a NPV of 76%; in 31 of 34 (91%) of these cases, the residual histologic subtype was superficial. Limitations Our sectioning technique did not evaluate 100% of the excision specimens. Conclusion Negative margins in a BCC biopsy are a poor predictor of residual disease in the patient. We recommend that clinicians treat these lesions, and that pathologists who comment on margin status of BCC biopsies consider adding a caveat to reflect these findings.

Background: Numerous researches have been done on the permanent maxillary first molars for the presence of an extra canal, especially the mesiobuccal roots for the presence of MB2 canals. Cone beam computed tomography (CBCT) has been used recently in the detection of these canals. However, literature discussing the efficacy and reliability of CBCT in the detection of these canals is scanty. Aims: This study aims to evaluate the efficacy of CBCT as a preoperative diagnostic aid in locating the second mesiobuccal canal in maxillary first molars. Methods: Selected sixty extracted maxillary first molars were placed in the skull base, and CBCT scans were done for evaluating the presence of MB2 canals in the mesiobuccal root. Sectioning of the roots at 3, 5, and 7 mm from the tip was performed and further examined under the microscope for the presence of the MB2 canals. Evaluations were done by two evaluators independently. Results of evaluations were statistically analyzed. Statistical analysis used were standard normal deviation (Z value), interrater reliability (Chronbach's alpha-), P value and receiver operating curve(ROC). Results and Conclusions: Detection rates of MB2 using both the methods did not show any significant difference (P > 0.05). CBCT was found to be a reliable tool for the detection of MB2 canal in maxillary first molar teeth when compared to gold standard sectioning technique.

Background Marginal fit is critical for the success and longevity of a dental restoration. Zirconia crowns can be fabricated either chair-side, in a dental laboratory or in a milling center; each can give different marginal fits results. However, discussion of the marginal fit of zirconia crowns when different fabrication methods are compared is lacking in the literature. Purpose To compare the marginal discrepancy (MD) and absolute marginal discrepancy (AMD) of computer-aided design, and computer-aided manufacturing (CAD-CAM) used in a dental laboratory and a milling center for producing monolithic zirconia crowns. Methods The marginal fit of 30 zirconia crowns cemented to typodont teeth was evaluated by means of a sectioning technique. Fifteen crowns were fabricated with a CEREC inLAB MC X5 from IPS e.max ZirCAD blocks. Fifteen crowns were fabricated using a LAVA milling center from LAVA Plus Zirconia Blocks. The 30 crowns were sectioned with a precision saw, and MD and AMD were subsequently measured using a light microscope. Data were analyzed using the one-way ANOVA technique to investigate significant differences in the marginal fit between the two fabrication systems (α = .05). Results The AMD dimension of the CEREC inLAB system was significantly smaller (P

The purpose of this study was to introduce the method and first results of a modified tooth sectioning technique for the extraction of horizontally impacted mandibular third molars (M3Ms) with large root bifurcation.A total of 300 horizontally impacted M3Ms with large root bifurcation in medically healthy patients were included in this prospective study. Patients were divided into 2 groups: the modified method group (test group), in which the M3M was sectioned between the distal root and the remainder of the tooth at the point of root bifurcation; and the conventional method group (control group), in which the M3M was sectioned between the crown and the root at the cementoenamel junction. Operation duration, postoperative reactions, complications, and patient satisfaction were analyzed and compared between the 2 groups.Each group included 150 M3Ms which were all successfully extracted. Operation durations in the test and control group were 10.48 ± 3.78 and 15.09 ± 4.24 minutes, respectively (P .05). The test group had significantly better results than the control group with regard to postoperative reactions and complications (P .05). Patients in the test group had higher satisfaction ratings regarding operation duration and the healing process than those in the control group (P .05).The modified method of tooth sectioning between the distal root and the remainder of the tooth can efficiently eliminate resistance from the bone and adjacent mandibular second molar and allow for just 1 sectioning of the M3M in most cases, which could make the operation straightforward and safe.

The dentinal radicular microcrack is a difficult clinical problem to diagnose and treat, and it is one of the most common reasons for tooth extraction. These microcracks start in the radicular dentin, and laboratory studies have linked crack formation to some routine endodontic procedures, namely root canal preparation, obturation, and retreatment. Most of these studies were performed using destructive methods, such as the sectioning technique, previously developed for the study of the internal anatomy of teeth. Nowadays, technological advances in the field of imaging may lead to a more thorough understanding of dentinal microcracks. This article seeks to critically appraise the methodological aspects involved in the study of dentinal radicular microcrack formation after root canal preparation, obturation, and retreatment.

Despite the long and widespread use of grafting in tomato cultivation, the structural changes that occur at the graft union during the early stages of the union remain poorly understood. In this study, the structural development of the graft union in tomato plants was examined 3, 5, 8, 11 and 14 days after grafting (DAG) using scanning electron microscopy (SEM) and a paraffin sectioning technique. The paraffin-sectioned images of the transection revealed that parenchymal cells from the graft union divided and proliferated in most combinations, and these cells could be detected at various stages of development. The SEM images of the scion and rootstock longitudinal sections showed that many interconnecting structures appeared at 8 DAG and were followed by a vascular rearrangement that did not connect the scion and rootstock. Vascular bundle bridges appeared at 11 DAG and connected the scion and rootstock. The connection of graft union between rootstock and scion is influenced by the plant growth condition. In our managed environment, period for formation of the connection structure formation between the rootstock and scion was 7-14 days after grafting.

BACKGROUND There are two methods used when examining fetal rabbit eyes and brain in teratology studies. One method employs prior fixation before serial sectioning (Wilson's technique) and the other uses fresh tissue (mid-coronal sectioning). METHODS We modified the mid-coronal sectioning technique to include removal of eyes and brain for closer examination and to increase the number of structures that can be evaluated and compared it to the Wilson's technique. We found that external examination of the head, in conjunction with either sectioning method, is equally sensitive in identifying developmental defects. We evaluated 40,401 New Zealand White (NZW) and Dutch-Belted (DB) rabbit fetuses for external head alterations, of which 28,538 fetuses were further examined for eye and brain alterations using the modified mid-coronal sectioning method (16,675 fetuses) or Wilson's technique (11,863 fetuses). The fetuses were from vehicle control or drug-treated pregnant rabbits in embryo-fetal development studies conducted to meet international regulatory requirements for the development of new drugs. RESULTS Both methods detected the more common alterations (microphthalmia and dilated lateral cerebral ventricles) and other less common findings (changes in size and/or shape of eye and brain structures). CONCLUSIONS While both methods are equally sensitive at detecting common and rare developmental defects, the modified mid-coronal sectioning technique eliminates the use of chemicals and concomitant fixation artifacts that occur with the Wilson's technique and allows for examination of 100% intact fetuses thereby increasing potential for detecting eye and brain alterations as these findings occur infrequently in rabbits

Background Radial sections are widely used to estimate adequacy of excision in canine cutaneous mast cell tumours (MCTs); however, this sectioning technique estimates only a small fraction of total margin circumference. This study aimed to compare histologic margin status in grade II/low grade MCTs sectioned using both radial and tangential sectioning techniques. Materials and Methods A total of 43 circumferential margins were evaluated from 21 different tumours. Margins were first sectioned radially, followed by tangential sections. Tissues were examined by routine histopathology. Results Tangential margin status differed in 10 of 43 (23.3%) margins compared with their initial status on radial section. Of 39 margins, 9 (23.1%) categorized as histologic tumour-free margin (HTFM) >0 mm were positive on tangential sectioning. Tangential sections detected a significantly higher proportion of positive margins relative to radial sections (exact 2-tailed P-value = .0215). The HTFM was significantly longer in negative tangential margins than positive tangential margins (mean 10.1 vs 3.2 mm; P = .0008). A receiver operating characteristic curve comparing HTFM and tangentially negative margins found an area under the curve of 0.83 (95% confidence interval: 0.71−0.96). Although correct classification peaked at the sixth cut-point of HTFM ≥1 mm, radial sections still incorrectly classified 50% of margins as lacking tumour cells. Radial sections had 100% specificity for predicting negative tangential margins at a cut-point of 10.9 mm. Conclusion These data indicate that for low grade MCTs, HTFMs >0 mm should not be considered completely excised, particularly when HTFM is

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.

The histopathologic assessment of a scalp biopsy for alopecia relies largely on the quality of the specimen provided for evaluation. There are a number of different protocols in the literature which have been proposed over the years, but no consensus has yet been reached as to the appropriate number of biopsies to be taken, or to which sectioning technique is the gold standard for achieving the best diagnostic yield. We herein review the pros and cons of the various protocols and share the experience with our St John's protocol.

A 3-year-old neutered male boxer dog presented with a 6-month history of a waxing and waning mass of the left dorsotemporal eyelid margin. Cytology and biopsy confirmed a diagnosis of mast cell neoplasia. Systemic staging of the dog failed to reveal any evidence of metastatic neoplasia. Owing to the location of the tumor within the eyelid margin and the wide surgical margins recommended for excision of mast cell tumors, Mohs micrographic surgery (MMS) was chosen for its potential to conserve tissues while providing intraoperative confirmation the tumor was completely excised. Utilizing MMS horizontal sectioning technique, 100% of the surgical margins were assessed prior to closure of the surgical wound. This represents the first time a comprehensive MMS protocol was used in a veterinary patient under general anesthesia.

Taxonomists are divided over the infrageneric classification and species delimitation within the genus Cycas. The division is largely determined by whether a broad or narrow species concept is adopted, the latter approach being based on apparently minor morphological differences. It is well known that cytokinesis in the cells of pollen provides important evidence for plant taxonomy, particularly at the higher taxonomic level. Here we present the first broad comparison of the cytokinesis of male meiosis in five species of Cycas. A comparative analysis of microsporogenesis in Cycas was carried out using conventional microscopy, semi‐thin sectioning, histochemistry, and fluorescence microscopy with a focus on the cytokinesis of meiosis in the pollen of dividing cells. Our observations confirmed that, contrary to previous reports, the cytokinesis in male meiosis of five species in Cycas is simultaneous at the end of second meiosis. The basic model of microsporogenesis and its systematic implications in Cycas is discussed based both on previous reports and our new results.

‘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...

A new technique for detailed morphological evaluation of scintigrams of thyroid lesions based on rapid, whole-organ sectioning technique combined with autoradiography is described. The findings in 10 thyroid specimens illustrate the possibilities for assessement of thyroid scintigrams, especially of hot nodules, by this technique.

SUMMARY 1 The vertical distribution of Oribatei in a black pine plantation soil was studied in situ using the soil sectioning technique. 2 Oribatei were most abundent in the upper 3 cm due to the greater abundance of suitable food in this region. 3 Larger species were usually confined to the upper layers but some smaller species were also abundant in this region. 4 A correlation between the size of the species and their penetration was not found to be statistically significant. 5 Nested analysis of variance showed seasonal redistribution in some species. 6 The vertical distribution of individual species is discussed, and partially explained.

The general outline of meiosis proposed by Wilson in 1925 included a diffuse stage following pachytene or early diplotene, although such a stage may be missing in some organisms. Different forms of such a stage are known to exist in male and female meiosis of many animals, but usually they are treated separately and not included as a special stage in the scheme of meiosis in modern textbooks. It was shown by a literature research that, up to 1940, the existence of a diffuse stage was recorded in meiosis of many plants (the sectioning technique used at this time made it easy to follow accurately the sequence of meiotic stages) but few authors considered this stage to be a common part of plant meiosis. Its existence was actually observed by many authors at this time, but it became a common tendency to regard it as due to “bad fixation”, or “fixation artefacts” only. Remarks about the existence of such a stage disappeared after the introduction of squash techniques, but started to reappear after 1960. Today, references about the existence of a diffuse stage are known from all groups of plants (Angiospermae, Gymnospermae, Pteridophyta, Bryophyta, Fungi, Algae). The conception of meiosis published by Wilson is thus found to be more close to reality and therefore it is proposed that such a concept is accepted as a general outline of meiosis.

In this work, the microstructure of an Al 3 Nb–Nb 2 Al–AlNbNi ternary eutectic obtained by directional solidification was analyzed. Because the phase arrangement of this eutectic is highly complex, this study involved a three-dimensional reconstruction of the microstructure using the serial sectioning technique. The visualization of the reconstructed microstructure revealed that the fibers possessed a high degree of sinuosity. Although these fibers were continuous in the growth direction, they displayed a tendency to move back and forth across a central axis.

Reconstruction and visualization of three-dimensional (3-D) pores are of interest for understanding microstructure–properties relationships in cast Mg-alloys. In this contribution, a montage serial sectioning technique is applied to reconstruct a large volume of the 3-D microstructure of a new high-pressure die-cast AE44 Mg-alloy at a high resolution. The 3-D reconstruction reveals that the shapes and morphologies of the gas pores in the AE44 alloy are substantially different from those in other important cast Mg-alloys, which may partly account for the AE44 alloy’s superior properties.

The contour method, a newly-invented sectioning technique for residual stress measurement, has the potential to measure the cross-sectional residual stress profile of a weld in a simple and time-efficient manner. In this paper we demonstrate the capability of the contour method to measure cross-sectional residual stress profiles, which are compared with neutron diffraction measurements and show excellent agreement. The results provide useful information for safetycritical design of welded components and optimization of welding parameters, and also illustrate the potential of the contour technique as a powerful tool for residual stress evaluation.

The concept of asperity sharpness has recently been developed into a technique for the description of abrasive particle shape. This paper reveals further discoveries on the nature of particle shape and applies sharpness concepts to nominally planar abrasive surfaces composed of self-arranged particle stacks. The main purpose of the investigation is to determine whether there are any significant changes of surface shape that are dictated by particle size; thus establishing to what extent particle stacking influences the well known particle size effect. In pursuing this objective it has been found that the average shape of particle asperities can be conveniently modelled by a power-law—this useful discovery simplifies the description of abrasive particle shape. In addition, when particles are affixed to a planar substrate, the resulting surface exhibits unique properties that are convenient for surface characterisation and the development of abrasion models. The behaviour of these surfaces is investigated in relation to the underlying particle properties. The serial sectioning technique used to investigate the abrasive surfaces is described in this paper and preliminary results are also presented.

We have studied, by a computer simulation, the feasibility of the radiotracer method for diffusion studies using short-lived radioactive nuclear beams as tracers. We have considered two typical examples of radiotracers that will be available in KEK-JAERI RNB facility, 18F (half-life: 1.8 h, β+-emitter) and 8Li (half-life: 0.83 s, α-emitter). The sample is set on a given temperature and irradiated by the tracer beams for a time-duration. In the case of 18F, the serial sectioning technique by the ion-beam-sputtering device is assumed to obtain the concentration-depth profile of the tracer diffused during the irradiation time. In the case of 8Li, the simulation reveals that the time-dependent yields of α particles can be used as a measure of the diffusivity of the tracer in a non-destructive way. The present method could be applied to measure rather large diffusion coefficients of various radiotracers with a short measuring time.

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.

Age estimation is particularly crucial for the conservation of the saiga antelope Saiga tatarica, but modern laboratory methods for aging have not previously been applied to this species. There is an urgent need for evaluation of the techniques that could be used for age estimation in order that long-term ecological data sets can be correctly interpreted and conservation advice given. We evaluated the repeatability, practical feasibility and comparability of three techniques for age estimation of saiga antelopes; the tooth sectioning technique (TS), the tooth eruption and wear technique (TEW), and a visual aging technique routinely used in field studies. We found that TS and TEW gave repeatable results, and agreed well. The visual method underestimated the age of males compared to laboratory methods. It assigned animals consistently to the age class of at least one year old, but less consistently to the age class less than one year old. Although studies of known-age animals are needed to evaluate precision and accuracy of these methods, we suggest that either TS or TEW would be suitable for aging saiga antelopes, with the choice being determined by practicalities such as the availability of the necessary expertise and equipment.

Damage in materials can be represented in many forms such as specific void or crack surfaces, the spacing between cracks, scalar representation of damage and general tensorial representation of damage. This paper presents methods to quantify the specific damaged surface area, the specific damaged surface area tensor, the damage tensor, the mean solid path among the damaged surfaces and the mean solid path tensor. The methods are general and use the reconstructed three-dimensional structure from tomography images and a virtual sectioning technique to obtain cross-sectional images needed for the quantification. The paper also presents the relation between the quantified damage parameters and their applications in mechanical modeling. This work is applied in particular to quantify the damage parameters of asphalt concrete specimens of the WesTrack project.

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...

Unbiased and efficient estimation of number density of features in opaque material microstructures has been quite difficult. In this contribution a montage-based efficient serial sectioning technique is presented as a practical solution for efficient estimation of number density in such microstructures. The new technique utilizes a combination of digital image analysis and unbiased disector sampling procedures.

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.

Grain boundary and interphase boundary diffusion has been investigated in the system Ag/Ni using the radiotracer serial sectioning technique. Ni segregation in Ag grain boundaries is strongly temperature dependent leading to the conclusion that Ni atoms are located mainly in the bulk planes adjacent to the grain boundary. From interphase boundary diffusion measurements in (110) oriented Ag/Ni interphase boundaries it can be deduced that the structure of this interphase boundary is incoherent.

We designed a series of experiments to verify the value of the diffusion coefficient of HNO 3 in ice at -15° C using a serial sectioning technique. Our first series of experiments with diffusion times of 70 to 100 h gave an average value of about 1.7 × 10 -11 cm 2 s -1 (StD 0.8 × 10 -11 ) and a second set of experiments at 1000 h resulted in an apparent diffusion coefficient of 10 -12 cm 2 s -1 . Our conclusion is that the observed gradients of HNO 3 in ice were spurious and the result of serial contamination of the surfaces during sectioning of the ice. We call the diffusion coefficients apparent because in the present experiment we could not distinguish between an undetectable diffusion coefficient and undetectable solubility. In either case, the validity of the previously published results is questionable.

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...

We attempted to settle the potential problems of bias caused by too soft earplugs and poor formation of the growth layers in age readings of common minke whales. Thus, we examined the feasibility of a new technique of incorporating gelatin in order to collect earplugs for age assessment. Frozen sectioning and histology of the earplug core were also used as methods to improve age estimation. Earplugs were collected by filling the space in the external auditory meatus with gelatin, hardening the gelatin, earplug and its fragments, by spraying with cooling gas, and removing the earplug embedded in gelatin. In 174 trials with common minke whales in the Western North Pacific of coastal waters of Japan in 2007–2009, it was revealed that embedding earplugs with gelatin minimized breakage and protected the neonatal line (NL). This method was particularly effective in younger animals. As a result, the readability was improved. We also examined the histological sections, which were sliced using the Kawamoto specialized frozen sectioning technique, and stained them separately with toluidine blue, haematoxylin and eosin, Sudan III, Sudan VII, and alizarin red S to display a clearer core surface image of the growth layers. The histological sections stained with alizarin red S provided the clearest images, in which we could easily identify both dark and pale laminations. This suggested a close relationship with the seasonal changes in calcium intake from feeding. Earlier age estimation methods focused on fat content in the growth layers; however, we found potential for an improvement in the readability of unclear growth layers when focusing on calcium.

Building a 3D microstructure database is gaining rapid attention as it provides material specific key knowledgebase toward ICME approaches. Recent advances in automated metallographic serial sectioning technology such as RoboMet.3D, has significantly improved metallographic procedures and control systems for the acquisition of high quality metallographs in the form of serial sections. However, the image registration for 3D reconstruction and the segmentation of actual microstructural attributes from the raw data is still challenging, particularly for polycrystalline materials. The present study demonstrates systematic efforts to improve the automated metallographic serial sectioning technique for the 3D microstructure data. In particular, comprehensive image-processing tools were developed for the segmentation of complex 3D microstructures. Its capability of handling various complex 3D microstructure data (from polycrystals to composites) is also demonstrated. Geometric and gray-scale features are calculated using voxel values and their scale-space relational analysis. We propose to build a volumetric image database that allows qualitative and quantitative comparison of different materials and their structural properties measured using image processing algorithms and micrographs.

The fit of In-Ceram copings and crowns was investigated in a laboratory study. Two methods were used, one a direct sectioning technique and the other a cement analogue technique using addition-cured polyvinylsiloxane impression material. The former method involved 40 crowns cemented and sectioned on their respective electroformed silver dies. For the second method, 80 analogues were embedded and sectioned. All measurements were made using a Reflex microscope. This showed In-Ceram crowns and copings to fit well with marginal openings and ranging from 1 to 63 microns and a mean of 19 microns. No significant difference in fit was found between chamfer margins and shoulder margins. The addition of porcelain to the In-Ceram coping and repeated firing cycles involved in building a crown did not alter the fit. It is concluded that In-Ceram crowns fit well in comparison to other crown types.

The feature size dependence of plasma etch rates has been the focus of recent theoretical and experimental study [1–3]. The effect, already problematic at submicron dimensions, can limit attainable structures and is expected to increase in importance as lateral dimensions are further reduced. In this paper, the models previously reported are developed further and a new nanostructure trench sectioning technique is used to extend etch rate measurements to features with lateral dimensions below 100 nm. The experimental results are compared to the new models.

This in vitro study compared microleakage along the dentin-restorative interface by use of a conventional single-surface and two stereoscopical protocols. The extent of microleakage in class V cylindric cavities that were restored with Scotchbond 2/P-50 was assessed after thermocycling and silver staining were performed. Specimens were randomized into three groups of 10 teeth for the three different protocols to be investigated. The categories were group 1, a single longitudinal section through the midline of the restoration, group 2, a multiple-surface protocol based on computer reconstruction of digitized images from multiple serial abrasions, and group 3, a clearing protocol based on immersion of demineralized specimens in methyl salicylate. The severity of microleakage for all groups was recorded on an ordinal scale and based on linear leakage length. The median leakage score for groups 1 through 3 was 2, 4, and 4, respectively. When comparisons were performed with nonparametric statistical analysis, both the clearing and the multiple-surface protocols recorded significantly more severe leakage than those detected from a conventional, single longitudinal, midline sectioning technique, (x2 = 8.595, p0.02). Furthermore microleakage patterns generated from the two stereoscopical protocols revealed extensive microleakage that advanced unilaterally or bilaterally through the dentin-restorative interface along the embrasure regions into the axial wall of the restorations. No significant difference was noted between the two stereoscopical protocols (Q = 0.260, p0.05), which suggested that the clearing protocol, which is less labor-intensive than the multiple-surface protocol, may be recommended for future comparative microleakage studies that involve the dentin-restorative interface.

The presence of separate bundles of nerve fibres in the gerbilline endolymphatic sac (ES) is described, paying particular attention to their ultrastructure and localization. One bundle, localized in the area of the subepithelium which separates the sigmoid sinus from the ES, is composed only of myelinated fascicles which, moreover, seem to have an isolated contact with the ES area. Other two single nerve fibres, much smaller in caliber, are localized in the ES subepithelium and laterally to the ES area, still close to the sigmoid sinus. These fibres, composed of myelinated and unmyelinated fascicles, seem to have a rather longitudinal orientation and, moreover, contract close relationships with the rich vascular network of the ES subepithelial tissue. As far as the course is concerned, the serial sectioning technique would suggest that the nerve fibres get very close to the ES epithelial cell layer, going proximal to distal. Speculations on the origin of this nerve contingent in the ES are proposed and discussed in view of possible new theories for pathogenesis and therapy of some inner ear diseases.

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.

A significant amount of research has been performed over the last two decades to characterize the microstructure of sand specimens and advance the understanding of the link between micro-structural properties and engineering behavior of these soils. Much of the research has been limited to two-dimensional (2-D) analysis that results in loss of information regarding the skeleton of the particle-pore structure and other attributes of the actual three-dimensional (3-D) microstructure. More recently, a number of techniques for studying these issues in 3-D have emerged. This paper uses a high-resolution optical microscopy based method for reconstruction of actual 3-D specimen microstructures. A montage and serial sectioning technique was implemented for creating 3-D microstructure volumes from 2-D optical images. The reconstructed 3-D digital structures were characterized for microstructural features. Specific attention was focused on shear band thickness. Simulated DEM sand structures were also constructed and characterized.

Results on the diffusion of Cl into CdTe are described. Diffusion anneals were carried out at selected temperatures in the range between 200 degrees C and 700 degrees C in evacuated SiO2 ampoules using a diffusion source of CdCl2 under saturated vapour pressure conditions. The concentration profiles were measured using a radiotracer sectioning technique. The profiles were found to be composed of four parts, to which a computer package consisting of the sum of four complementary error functions (erfc) gave satisfactory fits to the data. The fastest-diffusing component gave values of the diffusivity that agreed with previously published results. Proposals explaining how this type of diffusion may occur are given.