Altermagnetic lifting of Kramers spin degeneracy.

Lifted Kramers spin degeneracy (LKSD) has been among the central topics of condensed-matter physics since the dawn of the band theory of solids1,2. It underpins established practical applications as well as current frontier research, ranging from magnetic-memory technology3-7 to topological quantum matter8-14. Traditionally, LKSD has been considered to originate from two possible internal symmetry-breaking mechanisms. The first refers to time-reversal symmetry breaking by magnetization of ferromagnets and tends to be strong because of the non-relativistic exchange origin15. The second applies to crystals with broken inversion symmetry and tends to be comparatively weaker, as it originates from the relativistic spin-orbit coupling (SOC)16-19. A recent theory work based on spin-symmetry classification has identified an unconventional magnetic phase, dubbed altermagnetic20,21, that allows for LKSD without net magnetization and inversion-symmetry breaking. Here we provide the confirmation using photoemission spectroscopy and ab initio calculations. We identify two distinct unconventional mechanisms of LKSD generated by the altermagnetic phase of centrosymmetric MnTe with vanishing net magnetization20-23. Our observation of the altermagnetic LKSD can have broad consequences in magnetism. It motivates exploration and exploitation of the unconventional nature of this magnetic phase in an extended family of materials, ranging from insulators and semiconductors to metals and superconductors20,21, that have been either identified recently or perceived for many decades as conventional antiferromagnets21,24,25.

[Biopotentials of the urinary bladder during functional load].

The study aimed to investigate the specific bioelectrical activity of the urinary bladder walls at a functional load. MATERIALS AND METHODS: The study comprised five subjects aged 18-22 years who had no diseases of the urinary system. Participants signed an informed consent form before entering the study, which was approved by the Ethics Committee of our organization. Biopotentials from the ureter and urinary bladder area were recorded using the Neuro-Spectrum NeuroSoft-21 Neuron Spectrum-4 electroencephalograph, which has a higher sensitivity compared to other biopotential amplifiers. The sensitivity range of the electroencephalograph according to the manufacturer was in the frequency range from 0.05 to 250 Hz 1-1000 V/mm, the quantization frequency - up to 5000 Hz, the noise level - less than 0.3 V. The obtained data were in agreement with the results of the ultrasound and urodynamic studies, which implied the possibility to consider this method of registration of bladder biopotentials suitable for such a purpose. RESULTS: The analysis of the background spectra for the same time (at rest and under load) identified a correlation between them (correlation coefficient > 0.8). Three frequencies were chosen in the range from 0.5 to 2 Hz, for which the changes of the amplitude were most clearly traced in time. A correlation analysis (using the STATISTICA 10 software) showed a correlation between these three frequencies and background load (correlation coefficient 0.2). CONCLUSIONS: The water loading resulted in an increase in the activity of the bladder wall biopotentials after the 10th minute of registration. The functional load changed the pattern of the changes of the harmonics of the bioelectrical activity spectrum of the bladder walls: in the background record, the harmonics behaved almost identically in time, but after water loading, the amplitudes of the harmonics changed with the passage of time. One of the main findings of the work is the detection of several frequencies ranged from 0.5 to2 Hz (0.7, 1.5 and 1.7 Hz), which can be used to assess the functional state of the bladder wall.

[The influence of alternating magnetic field on in vitro litholysis of uroliths in blemaren water solutions].

THE AIM OF THE RESEARCH: increase of efficiency of urolith in vitro solution using water Blemaren medication solutions after their exposure to 2 Hz alternating magnetic field. MATERIALS AND METHODS: water solution of Blemaren medication with pH=6,15 in concentrations corresponding to single portion of medication (1 tablet m=3,5282 g per 250 ml of water) and uroliths (oxalates, urates including uncommon xanthine calculi). Composition of calculi was determined by means of X-ray tests and IR spectroscopy. Photometry of Blemaren with saluted portion of calculi was conducted. RESULTS: it was established that in the Blemaren solutions which had been previously exposed to 2 Hz alternating magnetic filed during one hour the solution process is 1.92 - 2 times more effective than in common water solutions. Discussion - in control solutions pH values increased 5.65 - 6.8 times in the course of time, whereas in the Blemaren solutions exposed to alternating magnetic field pH values remained virtually unaltered during the whole experiment. CONCLUSION: there were detected significant differences in pH values of Blemaren solutions and its solvent properties between solutions which were exposed to alternating magnetic filed and those which were not.

[CHARACTERISTICS OF THE URETER CONTRACTIONS IN CHILDREN WITH CHRONIC PYELONEPHRITIS].

The article presents results of electrophysiological study of the function of the ureter in the frequency range of 0.6-35 Hz, conducted in 100 children aged 5 to 13 years with chronic pyelonephritis. Data of 35 healthy people were used as a control. It was shown that the features of ureter contractions were significantly different in the two groups. Marked decrease of amplitudes of signal harmonics was found at a frequency of 1.4 Hz in patients with pyelonephritis compared to controls. Myostimulation in pyelonephritis group has led to an approximation of harmonic amplitudes to the values of the control group.

[Effects of low-frequency magnetic field on urolith solubility in vitro].

A 27% increase in solubility of urolith substance was observed in water pretreated with alternating magnetic field (22 Hz, 25 mT) for 60 min compared to untreated water. Changed density of distilled water without concrement in response to the impact of alternating magnetic field does not influence qualitatively on solubility of urolith substance in the urolith placement in the pretreated water. Shift in wave length of maximums in spectra of solution absorption evidences for more intensive solution of organic components of uroliths in water pretreated with alternating magnetic field than in untreated water.

[The clinical study of tympanic membrane mobility with the use of the autodyne technique].

AIM OF THE STUDY: to estimate the possibility of application of the autodyne method for the detection of nano-displacements of the tympanic membrane and diagnostics of ear diseases. METHODS: nano-displacements of the tympanic membrane were revealed with the use of the original laser-assisted autodyne technique for the measurement of nano-vibrations. The majority of the measurements were performed in the free auditory field. A total of 182 patients allocated to 7 groups depending on the form of hearing disturbances or their absence were involved in the study. RESULTS: the values of nano-displacement of the tympanic membrane at different levels of acoustic pressure have been obtained for otologically healthy individuals. The age dependence of this parameter was investigated in the absence of otological pathology. Similar studies were carried out in different groups of patients with the diseases of the middle and internal ears. The mobility of the tympanic membrane was shown to be significantly altered in the presence of adhesive events in the middle ear and pathological changes in the Eustachian tube. The possibilities of the clinical application of the proposed method have been estimated.

[The use of videooculography in schizophrenia]. / Ispol'zovanie videookulografii pri shizofrenii.

AIM: To study characteristics of oculomotor movements in schizophrenia. MATERIAL AND METHODS: Oculomotor characteristics of 30 patients with diagnosis of paranoid schizophrenia and 20 people of the control group were measured. RESULTS AND CONCLUSION: Parameters of specific eye movements, which are characteristic of this disease, have been identified. A comparison with the control group has been performed. It has been concluded that videooculography can be used as an additional method for examination of patients with schizophrenia.

Thermography-based blood flow imaging in human skin of the hands and feet: a spectral filtering approach.

The determination of the relationship between skin blood flow and skin temperature dynamics is the main problem in thermography-based blood flow imaging. Oscillations in skin blood flow are the source of thermal waves propagating from micro-vessels toward the skin's surface, as assumed in this study. This hypothesis allows us to use equations for the attenuation and dispersion of thermal waves for converting the temperature signal into the blood flow signal, and vice versa. We developed a spectral filtering approach (SFA), which is a new technique for thermography-based blood flow imaging. In contrast to other processing techniques, the SFA implies calculations in the spectral domain rather than in the time domain. Therefore, it eliminates the need to solve differential equations. The developed technique was verified within 0.005-0.1 Hz, including the endothelial, neurogenic and myogenic frequency bands of blood flow oscillations. The algorithm for an inverse conversion of the blood flow signal into the skin temperature signal is addressed. The examples of blood flow imaging of hands during cuff occlusion and feet during heating of the back are illustrated. The processing of infrared (IR) thermograms using the SFA allowed us to restore the blood flow signals and achieve correlations of about 0.8 with a waveform of a photoplethysmographic signal. The prospective applications of the thermography-based blood flow imaging technique include non-contact monitoring of the blood supply during engraftment of skin flaps and burns healing, as well the use of contact temperature sensors to monitor low-frequency oscillations of peripheral blood flow.

[Effects of decreased nystagmus amplitude in children periodically exposed to light].

The effect of steady-state nystagmus suppression has been found upon periodic light exposure of the eye. The paper describes the exposure facility and procedure based on the changes in the amplitude and frequency of light pulse until there is a response of a patient's nystagmus parameters that are continuously monitored by video-assisted computer system. After periodic light exposures, there was a persistent suppression of nystagmus and a steady-state increase in visual acuity by an average of 0.1.

[Video technology of qualitative control of eyeball movements in nystagmus]. / Videotekhnologiia kolichestvennogo kontrolia dvizheniia glaznogo iabloka pri nistagme.

A method for controlling voluntary movements of the eye is suggested, based on video-image processing and computer analysis. The program can be used for analysis of eye movements by its trajectory and spectrum. Results of measurements of voluntary movements of the eye in patients with nystagmus are presented. The results of measurements, characterizing the changes in nystagmus before and after operation for strabismus correction are discussed.

Determination of the amplitude and phase relationships between oscillations in skin temperature and photoplethysmography-measured blood flow in fingertips.

It is well established that skin temperature oscillations in fingertips coexist with blood flow oscillations and there is a certain correlation between them. At the same time, the reasons for differences in waveform and the delay between the blood flow and temperature oscillations are far from being fully understood. In this study we determine the relationships between spectral components of the blood flow and temperature oscillations in fingertips, and we ascertain the frequency dependences of amplitude attenuation and delay time for the temperature oscillations. The blood flow oscillations were considered as a source of thermal waves propagating from micro-vessels towards the skin surface and manifesting as temperature oscillations. The finger temperature was measured by infrared thermography and blood flow was assessed by photoplethysmography for ten healthy subjects. The time-frequency analysis of oscillations was based on the Morlet wavelet transform. The frequency dependences of delay time and amplitude attenuation in temperature compared with blood flow oscillations have been determined in endothelial (0.005-0.02 Hz) and neurogenic (0.02-0.05 Hz) frequency bands using the wavelet spectra. We approximated the experimental frequency dependences by equations describing thermal wave propagation through the medium and taking into account the thermal properties and thickness of a tissue. Results of analysis show that with the increase of frequency f the delay time of temperature oscillations decreases inversely proportional to f(1/2), and the attenuation of the amplitude increases directly proportional to exp f(1/2). Using these relationships allows us to increase correlation between the processed temperature oscillations and blood flow oscillations from 0.2 to 0.7 within the frequency interval 0.005-0.05 Hz. The established experimental and theoretical relationships clarify an understanding of interrelation between the dynamics of blood flow and skin temperature, and define possibilities and limitations of temperature measurements as a method of blood flow assessment in extremities.

Low-frequency magnetic radiation leads to the broadening of valent bonds in protein infrared spectra.

In recent years it has been discovered that a long-term exposure to low frequency magnetic fields leads to changes in activity of biological systems both in vivo and in vitro. Molecular mechanisms of this phenomenon are not clear. The present work uses infrared (IR) spectroscopy to study the effect of alternating magnetic field on a structural state of purified proteins. It was revealed that a 1-h exposure of aqueous solution of bovine serum albumin (BSA) and gluten isolated from wheat to 5.75Hz magnetic field with maximum amplitude of 25mTl resulted, respectively, in a ∼1.5- and 2-fold increase of the width of the band related to the vibrations of valent bonds in the range of 3500-2750cm(-1) (p<0.05). Unlike aqueous solutions, the desiccated BSA films did not exhibit any effect of magnetic field on parameters of IR-spectra. It is suggested, that low frequency magnetic fields induce the broadening of bands in IR spectra due to changes in structural organization of delocalized protein-bound water molecules thereby affecting macromolecules and related cell reactions.