A morphological study of dentinal nerve endings

Particulate growth processes in Ar+SiH4 RF plasmas are studied using ultraviolet light-absorption and scanning electron microscopic (SEM) methods. Measurements of particulate size and density using the SEM method show that they grow through three phases: nucleation, rapid growth and growth saturation. Such features of temporal evolutions of their size and density are very similar to those for He+SiH4 RF plasmas previously obtained by SEM and in situ laser light scattering methods. It is also found that particulates in two different size ranges coexist after the initiation of the rapid growth phase, and their coagulation plays an important role in this phase. Close similarities among spatial profiles of Si emission intensity, Si density, and amount of particulates are revealed in wide discharge-parameter ranges of 1–100% SiH4, 11–20 Pa, and 40–100 W. These results suggest that many short-lifetime neutral radicals such as SiHn (n=0–2) contribute to nucleation and subsequent initial growth of a particulate, since other short-lifetime radicals are also expected to have similar spatial profiles.

In this paper the advantages of application of the nanocomposite track membranes (NCTM) with TiN coating as the substrates for sample preparation for their investigation by methods of electron microscopy are discussed. This membrane material was obtained by the ion-plasma sputtering of TiN coating on the polymer track-etched membrane. The physicochemical properties of NCTM were researched. Preparation technique allows to separate nanoand microdimensional samples from dry, liquid and gas mixtures for their investigation by methods of scanning and transmission electron microscopy.

The gap junction (GJ) of stratum granulosum cells was investigated in growing and mature follicles of the mouse by means of light- and electron-microscopic immunohistochemistry, freeze-fracturing and deep-etching methods. GJ increased in number and size in concert with the progress of follicular maturation and decreased rapidly in the preovulatory mature follicle. GJ membrane showed invagination, most remarkably at 5 h after hCG injection, within the cytoplasm of the granulosum cell. Two types of internalization seemed possible, annular internalization and highly convoluted tubular invagination, both by an actin-mediated mechanism. At least, a part of the internalized GJ membrane seemed to be degraded by a certain lysosomal enzyme (s). Connexin43 (derived from rat cardiac muscle GJ) was indicated to be a constituent of GJ protein in the mouse stratum granulosum cell. There was no GJ particle coexisting with tight junctional strands; by contrast, a formation plaque appeared quite often on granulosum cells at various stages. Such a plaque is presumed to represent a precursor structure of the new GJ of these cells. So far examined, however, the formation plaque failed to show positive reaction against anti-Cx43 antibody.

The effects of doxycycline on the morphology and function of donor erythrocytes were studied by scanning electron microscopy. The antibiotic in concentrations of 7.8 × 10(-5) and 7.8 × 10(-6) mol/liter induced heterogeneous changes in the surface architectonics in the erythrocyte population. These data indicated stimulation of erythrocyte "aging" under the effect of doxycycline.

Until recently, a few reports have been published as to the methods for observing intracellular structure by means of scanning electron microscopy. Makita and Sandborn saw intracellular granules in the glands of the hen oviduct with tissue sections by means of Smith-Farquhar tissue sectioner. Geminario and McAlear applied the freeze-fracturing technique in order to ascertain the intracellular structure of retinas from mice.A new method, attempted by us, embedding the materials in epoxy resin and cracking it into two pieces after freezing, is described below with its application to cytology.1. The pieces of tissue are fixed in glutaraldehyde and osmium tetroxide.2. They are dehydrated by graded series of ethanol and propylen oxide.3. Then they are embedded in small gelatin capsules (size no. 2) which are filled with Cemedine 1500 (epoxy resin) without any catalysts (Epon 812 or Rigolac can be used but the temperature for hardening them is very low, -80°C).

Experimental investigation on the combustion characteristics of aluminum in air

Based on the large-area aging and cracking phenomena of Liquid Silicone Rubber (LSR) composite bushing sheds occurred in power grid, the research has been performed on LSR composite bushing sheds energizing for many years By using the methods of Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetry (TG) analysis, the authors analyze different parts’ aging properties, microstructures and composition changes of LSR bushing sheds. The experimental results show that the natural environment may be one of the important factors that cause the LSR aging, gradually from the surface to the interior, there are no new groups generated in the process of aging, but the long chain content, the crosslinking degree and the side chain methyl number of LSR decrease obviously, and along with the aging aggravation, the organic composition content in LSR reduces gradually. This research poses great reference significance for better understanding aging mechanism of LSR, scientifically evaluating its lifetime, and guiding scene operational maintenance.

Development of gap junctions between gastric surface mucous cells during cell maturation in rats

Different methods of scanning electron microscopy in combination with different sample preparation techniques have been compared by an example of decellularized rat diaphragm matrices. It is shown that a combination of scanning electron microscopy under natural environmental conditions, allowing one to investigate tissue samples in a state similar to native, with the conventional high-vacuum microscopy of samples obtained by drying at the critical point, provides the most complete microstructural analysis of native and decellularized tissue samples.

A method of immunocytochemistry and low-voltage scanning electron microscopy (SEM) is described for visualization of the epidermal growth factor membrane receptor (EGFR). The specific labelling is achieved of antigenic sites on the surface of prefixed cells. The advantage of this approach over existing techniques is the capability for unlimited high-resolution surface examination at the single cell level. This is achieved by using low acceleration voltage (V0) and either very thin or no coating of the specimens to prevent the label from being masked. Furthermore, by using conventional field emission SEM and a highly sensitive detector for backscattered electrons, detection of the gold-conjugate (< 10 nm in diameter) becomes possible even at low V0. A431 cells (human epidermoid carcinoma) show intercellular variability in their EGFR area density. Highest density was recorded upon cells in the mitotic stage of the cell cycle due to a decrease in the relative surface of rounded versus flattened cells. At the ultrastructural level a marked heterogeneity was also seen on the surface of contracted cells, where enhanced labelling could be observed only at the tips of microvilli. In contrast, spread cells displayed a homogeneous receptor distribution due to their smooth surface.

The use of various electron microscopy techniques to study superconductors has been established since the 1980s, encompassing both high-resolution transmission electron microscopy (HRTEM) and lower magnification scanning electron microscopy (SEM). A significant challenge with these methods is the temperature dependence of imaging within the electron microscope, which necessitates noise reduction and specialized cooling systems, such as Low-Temperature Scanning Electron Microscopy (LTSEM). Programmable stages with temperature stabilization allow for analyzing temperature dependencies similar to studies on dielectric composites and semiconductors. Attempts to replace SEM and HRTEM with simpler scanning probe and tunnelling microscopy methods have not resolved the initial challenges, as they still require advanced cooling setups. The SEM benefits of scanning for large area investigations with satisfactory temporal dynamics are often overlooked. The interaction of the superconductor with the electron beam not only visualizes but can also contrast and modify samples, revealing cooperative or additive defects observable at micro- and mesoscopic levels. Therefore, it is advisable to study the charge structure of the surface of high-temperature superconductors at real temperatures. The proposed methodology involves using Y-modulated detection techniques with JEOL microscopes, applicable in both Charge Collection Scanning Electron Microscopy (CCSEM) and electronic spectroscopy methods. This approach allows for detailed 3D topographical imaging of surface charging structures/textures created by charged structures.

Thermoluminescence (TL) of quartz grains has been used to date a soil horizon at each of four sites in a chronosequence of freely drained podzols at Cooloola and North Stradbroke Island. The chronological order of the TL dates is in agreement with the sequence of inferred ages based on stratigraphic, geomorphic, denudational and pedological evidence, but at least one of the TL dates is of considerably greater age than the field evidence implies. Possible explanations of this anomaly are discussed. Differences in the nature of the quartz grains and the various pre-treatments used in TL dating were also examined by using a combination of thermogravimetric analysis (TGA), differential thermal analysis (DTA) and scanning electron microscopy (SEM) methods. The DTA showed no dissimilarity among the quartz samples from the different sites, but the TGA results showed significant weight losses for some samples and pretreatments. The SEM method further showed that weight loss is associated with water-sorbing substances (allophanic materials) present as coatings on grain surfaces and/or in cracks within grains.

(2009 31 0 , 2009 32 4 ) ABSTRACT: This study was carried out to assess the antilisterial potential of ethyl acetate (EtOAc) extract of a marine isolate of Aspergillus sp. The in vitro antilisterial efficacy of ethyl acetate extract was examined using disc diffusion, minimum inhibitory concentration (MIC) determination, cell viable count and scanning electron microscopic (SEM) methods against the employed strains of Listeria monocytogenus .T he ethyl acetate extract (300 g disc μ -1 ) exhibited a promising antilisterial effect as diameters of inhibition zones against L. monocytogenes ATCC 19111, 19116, 19118, 19166 and 15313, which were found in the range of 11-17 mm along with their MIC values ranging from 125 to 1000 g ml μ -1 , respectively. Also the EtOAc extract had strong detrimental effect on the viable count of the tested L. monocytogens ATCC 19166. Furthermore, scanning electron microscopic (SEM) study demonstrated potential detrimental effect of ethyl acetate extract on the morphology of L. monocytogenes ATCC 19116 at the used MIC concentration. These findings strongly support the role of ethyl acetate extract of a marine isolate of Aspergillus sp. as an antiliterial potential.

Methods of transmission and scanning electron microscopy and chemical microanalysis, electron diffraction, and X-ray diffraction were used to systematically study the structure and the chemical and phase composition of the Ni50Ti38Hf12 alloy synthesized by rapid quenching from the melt and subjected to various heat treatments. The critical temperatures of the devitrification of the initially amorphous rapidly quenched alloy and the B2 ↔ B19′ thermoelastic martensitic transformations have been determined. The lattice parameters of the B2 austenite and thermoelastic B19′ martensite have been measured. The main features of the formation of an ultrafine-grained structure in the alloy and the subsequent phase transformations (martensitic transformation and the decomposition with the formation of an intermetallic phase of the (Ti,Hf)2Ni type) have been studied depending on the regimes of heat treatment. Based on the results of measurements of mechanical properties upon tension (σM, σu, and δ) and the shape-memory effects (degree of shape recovery depending on the deformation by bending; and magnitude of the reversible strain erev), regimes for obtaining high-strength and plastic states of the alloy with a shape-memory effect have been established.

A kinetic diagram of Ge growth on Si is constructed by methods of fast electron diffraction and scanning electron microscopy. Activation energies of morphological transitions from two-dimensional to three-dimensional growth and from hut-clusters to dome-type islands are determined. The curve of the 2D–3D transition has two segments that follow the Arrhenius law and refer to different mechanisms of two-dimensional growth: two-dimensional island mechanism in the temperature range of 300–525 °C with the activation energy of −0.11 eV and step motion in the temperature range of 525–700 °C with the activation energy of 0.15 eV. Transitions from hut-islands to dome-islands are also observed. The curve constructed for the hut-dome transition is approximated by two exponential segments that obey the Arrhenius law. The hut-dome transition activation energy is 0.11 eV in the temperature range of 350–550 °C and 0.24 eV in the temperature range of 550–700 °C. The maximum density of islands in the case of Ge growth on a Ge x Si1−x layer reaches 4 · 1011 cm−2. An increase in the composition leads to an increase in the density of Ge islands owing to a decrease in the length of migration of Ge adatoms on the Ge x Si1−x surface, as compared to the case of Ge growth on Si. The periodicity N, which is manifested as a (2 × N) superstructure, decreases during the reconstruction from 14 to 8 with increasing Ge content in the Ge x Si1−x layer. An increase in thickness or temperature leads to a decrease in periodicity and testifies to Ge segregation; in this case, stress relaxation occurs, which reduces the Ge diffisivity.