Thermostatic control system using a single-chip microcomputer and thermoelectric modules based on the Peltier effect

A flexible temperature-controlling system matched with the liquid Thermostatic control circuit is based on a single-chip microcomputer. Thermoelectric modules based on the Peltier effect are used for sample cooling and heating. The accuracy of the temperature maintenance is better than 0.1°C in a range of -20 to +70°C. The system is designed for NMR relaxometers but can be also used to control the temperatures of any volume-comparable objects (≈50 cm3)

Pulse Train Microprocessor Programmer for NMR Relaxometers-Diffusiometers

A pulse train programmer for a spin-echo NMR relaxometer-diffusiometer is based on an AT89C51-24PC microcontroller. The programmer ensures the arbitrary generation of pulse trains with a minimum train step of 30 μs and recording of up to 30000 10-bit amplitudes of spin-echo NMR signals with a minimum quantization step of 3 μs. The all-in-one one-board programmer is connected to a computer serial asynchronous data port, which is compatible with NMR relaxometer-diffusiometers of almost any design

Pulse train microprocessor programmer for NMR relaxometers-diffusiometers

A pulse train programmer for a spin-echo NMR relaxometer-diffusiometer is based on an AT89C51-24PC microcontroller. The programmer ensures the arbitrary generation of pulse trains with a minimum train step of 30 μs and recording of up to 30 000 10-bit amplitudes of spin-echo NMR signals with a minimum quantization step of 3 μs. The all-in-one one-board programmer is connected to a computer serial asynchronous data port, which is compatible with NMR relaxometer-diffusiometers of almost any design

Estimating the size spectrum of lower ionosphere irregularities from oblique-sounding data

A procedure for reducing experimental ionospheric oblique-sounding data is considered. This procedure allows the size spectrum of scattering lower ionosphere irregularities and the rms value of the neutral wind to be estimated from the power spectrum of a scattered radio signal. The problem reduces to solving a Fredholm equation of the first kind; an empirical model of the scattered-signal spectrum is used for its reguiarization. The experimental data obtained on the mid-latitude Moscow-Kazan path in 1986-1990 are used to test its efficiency. The internal scale of turbulence in the E region of the ionosphere is estimated. Copyright © 1999 by MAHK "Hayka/Interperiodica"

Micromagnetic modeling of autoresonance oscillations in yttrium-iron garnet films

One of the main problems of magnonics is finding the ways of efficiently spin waves excitation in a magnet. This paper considers the method of nonlinear amplification by phase locking of amplitude of dynamic magnetization in yttrium-iron garnet film performed by micromagnetic modeling with MuMAX3 software taking into account the real materials parameters. It is shown that the excited magnetization precession can be considered as a autoresonance phenomena. The intensity of the autoresonance in ferrimagnetic yttrium-iron garnet films has threshold dependence on the chirp rate of the exciting magnetic field. © Published under licence by IOP Publishing Ltd.Russian Foundation for Basic Research, RFBR: 19-32-90014Ural Branch, Russian Academy of Sciences, UB RAS: МК-4959.2018.2The work was carried out within the framework of the state assignment on the topic "Spin" №АААА-А18-118020290104-2, "Alloys" № АААА-А19-119070890020-3 and project №18-10-2-37 of the Program of the UB RAS, supported by Grant of the President of the Russian Federation № МК-4959.2018.2, also the reported study was funded by RFBR, project number 19-32-90014

Ambiguity of mapping the relative phase of blood pulsations

©2014 Optical Society of America. Blood pulsation imaging (BPI) is a non-invasive optical method based on photoplethysmography (PPG). It is used for the visualization of changes in the spatial distribution of blood in the microvascular bed. BPI specifically allows measurements of the relative phase of blood pulsations and using it we detected a novel type of PPG fast waveforms, which were observable in limited areas with asynchronous regional blood supply. In all subjects studied, these fast waveforms coexisted with traditional slow waveforms of PPG. We are therefore presenting a novel lock-in image processing technique of blood pulsation imaging, which can be used for detailed temporal characterization of peripheral microcirculation

PHOTODYNAMIC DIAGNOSIS AND FLUORESCENCE SPECTROSCOPY IN SUPERFICIAL BLADDER CANCER

A comprehensive fluorescence technique has been developed to study the urinary bladder mucosa in patients with superficial bladder cancer (BC), by using alasense, white light cystoscopy, fluorescence cytoscopy, and local fluorescence spectroscopy in vivo. Quantification of urothelium fluorescence in the red emission foci of 5-ALA-induced protophorphyrin, with the local autofluorescence intensity being borne in mind, has been shown to increase the specificity of photodynamic diagnosis of superficial BC from 70 to 85% (p ≤ 0.05) and the total accuracy of the technique from 80 to 86%

Fast vascular component of cortical spreading depression revealed in rats by blood pulsation imaging

Cortical spreading depression (CSD) is a slowly propagating wave of depolarization of neurons and glia and has a less characterized vascular component. CSD is a commonly used phenomenon to test new methods of live brain imaging. Application of a blood pulsations imaging (BPI) technique to study of CSD induced with high-potassium solution in rat cortex allowed us to visualize for the first time the novel vascular component of a CSD wave. In our study, this wave component propagated in the limited part of the cortex along the bow-shaped trajectory in sharp contrast with concentric development of CSD measured by concurrently applied optical intrinsic signal (OIS) imaging technique. It was associated with a significant increase of the blood pulsations amplitude (BPA), started with a delay of 20 to 90 s comparing to signal measured with OIS, and propagated 40% faster than OIS signal. These findings suggest that the BPA and slower change of the cerebral blood volume are not directly related to each other even though both characterize the same vascular system. Our study indicates that the BPI technique could be used for characterization of the new pulsatile vascular component of CSDs in animal models of migraine, stroke, and brain trauma. © Society of Photo-Optical Instrumentation Engineers