Ultrastructural studies of microtubules and microtubule organizing centers of the vertebrate olfactory neuron.

The olfactory neuron is specialized along its length into highly determined morphological regions. These regions include the dendritic cilia, dendritic vesicle, dendritic shaft proper, perikaryon, axon, zone of transition where the axon widens as it approaches its termination, and the axon terminal. Except for the zone of transition and the terminal, characteristic populations of microtubules occur in these compartments. In the olfactory vesicle, three discrete microtubule organizing centers (MTOCs) nucleate microtubules: the basal body, the lateral foot associated with the body, and dense masses of nearby material. Little is known about MTOCs elsewhere in the neuron, although the polarity of the axonal microtubules indicate that they originate at or near the perikaryon. An attempt is made to summarize what is known of the origin, structure, distribution, and function of microtubules in vertebrate olfactory neurons, which are useful model systems in which to study microtubules. Information about olfactory neuron microtubules may be applicable to neurons in general (e.g., the discovery that axons contain microtubules of uniform polarity was first made in the olfactory neuron) or to microtubules in other eukaryotic cells.     

A scanning probe microscope for studying electron transport at low temperatures

A scanning probe microscope that allows studies of electron transport—in particular, in carbon nanotubes at cryogenic temperatures—has been developed. The stiff structure of the microscope and its small transverse dimensions allow scanning to be performed in the atomic-force-microscope mode of a portable Dewar flask with a neck diameter of >40 mm without using additional vibration insulation.     

An installation for studying the magnetoelectric effect

An installation designed for the measurement of the magnetoelectric effect at temperatures of 4.2–350 K in a constant magnetic field of 0.1–4 kOe and alternating electric field of 10⁴V/cm with a frequency of 20 Hz-8 kHz is described. Using the method of measuring the mechanical rotational moment applied to the electric-field-induced magnetic moment in an external magnetic field made it possible to achieve high sensitivity of measurements and to study the electric field effect on the magnetoanisotropic properties of matter.     

Apparatus for studying fretting fatique in vacuum

Recent investigations on the mechanism of fretting fatigue have indicated that mechanical damage, not chemical corrosion, has the largest effect in decreasing structural component life. Since there is no general agreement on the mechanism of fretting fatigue, an experiment has been designed to evaluate statistically the relative role of the mechanical process and the chemical process in reducing fatigue life. An initial step was to develop an apparatus that allows fretting fatigue tests to be performed in both laboratory air and vacuum environments. A detailed discussion of the experimental apparatus and experimental procedure are presented in this paper. Also typical test results are presented. It is found that fretting fatigue in vacuum is about ten times slower than that in laboratory air. Fractographic analysis of the wear surface indicated that less severe fretting damage occurred in the vacuum environment.     

Experimental setup for studying dynamics of the calcium interaction in cells

A calcium cell signaling system is one of the first, which were formed in the course of evolution of systems. The understanding of calcium binding–uncaging dynamics is crucial in studies of corresponding intracellular processes. By now, a great number of calcium-dependent processes have been investigated. However, works that fully consider these processes are absent. This is specified in many respects by the instrumental abilities. In this work, requirements for the experimental setup intended for comprehensive studies of calcium interaction dynamics are briefly formulated, its block diagram is described, and the results of test experiments are presented.     

An experimental procedure for studying the flow in plane strain extrusion

An experimental procedure is described for observing the flow of aluminium through near frictionless wedge-shaped plane strain extrusion dies. The selection of the billet size and shape, type of lubrication, die design and photographic grid printing technique are described. It is shown that the use of a square chequerboard pattern of 0.1 mm side enables the flow to be observed in considerable detail and flow fields are given for the extrusion of annealed aluminium alloy 5086 through 15° and 60° half angle dies with 50% reduction in thickness.     

An automated laser thermometer for studying plasma processes in the microtechnology

The design and characteristics of an automated temperature sensor of dielectric and semiconductor substrates in apparatuses for film deposition and etching of microstructures are considered. The temperature is measured via the laser interference thermometry technique as wavelengths of 0.633 and 1.15 μm of a He-Ne laser. A signal-to-noise ratio of ～30 dB attained in the system is such that the device is sensitive to a change in the substrate temperature of 0.01 K. The heating and cooling of the wafer are recognized automatically and displayed via a graphic interface in real time. An interferogram recorded during substrate heating or cooling, the time dependence of the temperature after the discharge initiation, and the temperature dependence of the substrate-heating power are displayed on the monitor. For 0.5-mm-thick silicon substrates, the measurement range at a wavelength of 1.15 μm extends from cryogenic temperatures to 650 K.     

Electrochemical techniques for studying tribocorrosion processes

The combined corrosion-wear degradation of materials in sliding contacts immersed in electrically conductive solutions can be investigated in situ by electrochemical techniques. Such techniques are the open circuit potential measurements, the potentiodynamic polarization measurements, and the electrochemical impedance measurements. In this paper, capabilities and present limitations of these techniques are discussed based on a tribocorrosion study of a AISI 316 stainless steel and an iron-nickel alloy immersed in aerated 0.5 M sulfuric acid and sliding against a corundum counterpart. Some novel insights into the tribocorrosion mechanism gathered in this way are discussed.     

A speckle-interferometric device for studying the cell biological activity

A modernized device intended for diagnosing the temperature-dependent activity of cells is described. The activity of cells was determined by finding the correlation coefficient of optical signals in speckle patterns recorded at different moments of time. It is shown that, as the temperature increases from 26 to 36°C, variations in the optical paths in cells increase from 16 to 26 nm. This is probably associated with the physiological activity of cells—trapping of large molecules or their conglomerates. In contrast to the previous variant of the device design, instead of a lipid membrane, a cell monolayer was used, which was cultivated on a plane-parallel glass plate. In order to reduce variations in the optical path lengths in a nutrient solution, a 1.7-mm-thick plane-parallel glass plate was additionally inserted into the cuvette. The modernization of the device also includes heating of the cuvette with hot air flows.     

Optimal-experimentation methodology in studying the cutting processes

A fundamentally new methodology for investigating any cutting process is outlined. This methodology reduces the volume and difficulty of the experiments required by several orders of magnitude.     

A new technique for studying the chip formation process in diamond turning

A new technique to examine the chip formation process has been developed. This experimental method involves cutting along the interface of two workpieces that have been joined, stopping the cut, retracting the tool and then separating the two halves of the workpiece. By viewing the cross section of the chip in the scanning electron microscope (SEM), the angle of shear and structure of the chip can be observed. The value of the technique is increased by measuring the tool forces while producing the chip. The shear and normal stresses on the shear plane and the forces attributable to elastic deformation of the workpiece can be calculated from this shear angle and the measured tool forces.     

A simple apparatus for studying the wear of tungsten carbide

This paper describes a simple apparatus which has been used for experiments on the transfer of radioactive tungsten carbide to steel and copper during moderate speed sliding under various conditions. A flat plate of metal 6 inches in diameter is rotated beneath a small tungsten carbide slider which carries loads up' to 4 kg and moves radially inwards. The resulting wear track forms a close spiral about twenty feet long. A great advantage of the method is that zones of the metal plate can be treated differently and the effects on transfer of the active slider can be studied in detail from autoradiographs. It is found that the wear rate adjusts very rapidly (within a few milli-seconds) to a change in the plate surface.     

STRELA experimental setup for studying charge-exchange processes

The STRELA experimental setup designed for studying charge-exchange processes in deuteron-proton collisions at energies above 1 GeV is described. The setup is a one-arm magnetic spectrometer the main elements of which are drift chambers. The setup has been tested by irradiation in a deuteron beam with a momentum of 3.5 GeV/c at the Nuclotron accelerator complex (Laboratory of High Energy Physics, Joint Institute for Nuclear Research (JINR)). Algorithms for track searching and reconstruction in drift chambers have been developed and tested using real events. The attained spatial resolution of the chambers is in the range of 90–120 μm, which is sufficient for studying the process we are interested in.     

Application of ellipsometry for studying bio-organic media

Thin films obtained by centrifugation of blood serum of healthy people and patients with diffuse pathology of liver with different degrees of fibrosis are studied by means of spectroscopic ellipsometry. The physical properties of the films are found to depend on the bio-organic composition of blood serum, which, in turn, is determined by pathological processes proceeding at different degrees of liver fibrosis. Correlations between the bio-chemical parameters of blood serum and ellipsometric data are obtained. Pilot ellipsometric experiments on studying blood serum with observations of the plasmon resonance of patients with intestinal tract tumors are performed. A persistent specific interaction between antigens of patient’s blood serum and SD24 monoclonal antibodies is found, which alters the position of the surface plasmon resonance. It is demonstrated that ellipsometry is a high-sensitivity nondestructive inexpensive express method of screening, i.e., preliminary diagnostics of disease stages for patients with pathologies of internals.     

Diffraction interferometer for studying refractive index dynamics

An experimental assembly is created and a method for simultaneous studying dynamics of phototransformation of holographic photopolymer materials by spectrophotometric and interferometric methods is elaborated. A special diffraction interferometer with combined branches is developed. The interferometer ensures the sensitivity to the change in the refractive index Δn ～ 10^?3 for ～100 μm specimens.     

Acoustic equipment for studying human respiratory sounds

Equipment for recording respiratory and voice sounds from the human body surface is described. An acoustic detector based on an electret microphone and equipped with a stethoscopic head and remote two-channel amplifier of signals of acoustic detectors is designed. The acoustic detectors (preamplifier) are connected to the microphone (linear) input of the remote sound card connected to the personal computer, which processes signals with the use of specialized and universal software.     

A spectropolarimeter for studying solar magnetic fields

A spectropolarimeter based on a ferroelectric liquid-crystal modulator is described. An optical system with spatial modulation of the positions of the components of Zeeman splitting is a specific feature of this instrument. In comparison to the familiar instruments, the developed spectropolarimeter utilizes the light flux more efficiently and contains only one photodetector array. An operating spectropolarimeter developed at the Sayan Solar Observatory is considered as an example. Comparative estimates of noises in different operating modes are presented.     

Application of frustrated total reflection for studying cells in vitro

A mathematical analysis of the dependence of the light flux scattered upon frustrated total reflection (FTR) on the angle of incidence of the light beam is presented for monolayers of spread and spherical cells. It is shown that using these relationships it is possible to estimate the refractive index of hyaloplasm at cell-substrate contacts and to study the flattening of the cell surface facing the glass. Analysis of FTR for single cells is presented. A condition is given that must be fulfilled for the brightly shining regions of the cell to be interpreted as the sites of attachment of the cell surface to glass. The condition defines the range of angles of incidence at which FTR does not depend on the optical properties of the cytoplasm portion being at a distance from the glass. The fulfillment of this condition is necessary for spectroscopic and ellipsometric studies of cell surface contacting the glass, by means of FTR. The conclusions are confirmed by experimental data. A peculiarity of light scattering by cells, associated with the coherence of the incident light beam is discussed.     

An automated facility for studying acousto-optical phenomena in magnetic materials

A multifunctional automated experimental setup for studying magneto-optical, magneto-acoustic, and acousto-optical properties of magnetically ordered substances is described. This facility makes it possible to investigate physical phenomena in a substance exposed to simultaneous effects of optical radiation in the near-IR region and acoustic fields of up to 10⁵ W/m² in a magnetic field of up to 1.67 × 10⁶ A/m.