Direct observation of the transition from spin waves to the magnon Bose condensate.

Bose-Einstein condensation occurs at an appropriate density of bosonic particles, depending on their mass and temperature. The transition from the semiclassical paradigm of spin waves to the magnon Bose-Einstein condensed state (mBEC) was obtained experimentally with increasing magnon density. We used the Faraday rotation effect to study the spatial distribution of the magnon density and phase far from their excitation region. A coherent magnetization precession was observed throughout the sample, which indicates the formation of a magnon BEC. It is shown that this result under experimental conditions goes beyond the applicability of the Landau-Lifshitz-Gilbert semiclassical theory.

Optical registration of a coherent magnon state outside of the excitation region.

Magnons have demonstrated enormous potential for the next generation of information technology and quantum computing. In particular, the coherent state of magnons resulting from their Bose-Einstein condensation (mBEC) is of great interest. Typically, mBEC is formed in the magnon excitation region. Here we demonstrate for the first time by optical methods the permanent existence of mBEC at large distances from the magnon excitation region. The homogeneity of the mBEC phase is also demonstrated. The experiments were carried out on films of yttrium iron garnet magnetized perpendicular to the surface and at room temperature. We use the method described in this article to develop coherent magnonics and quantum logic devices.

Quantum limits of position-sensitive photodiodes.

The split photodiode and the lateral effect photodiode are two popular detectors for measuring beam displacement. For small displacements of a Gaussian beam, which is the case of interest here, they are often seen as equivalent and used interchangeably, giving a signal proportional to the displacement. We show theoretically and experimentally that in the limit of low technical noise, where the signal to noise ratio is dominated by the shot noise of the light, the lateral effect photodiode produces a better signal to noise ratio than the split photodiode, owing to its optimum spatial detector response. This quantum advantage can be practically exploited in spite of the intrinsic thermal noise of the lateral effect photodiode.

Magneto-optical imaging of coherent spin dynamics in ferrites.

The explosive development of quantum magnonics is associated with the possibility of its use as macroscopic quantum systems. In particular, they can find an application for quantum computing processors and other devices. The recently discovered phenomenon of magnon Bose-Einstein condensation and coherent precession of magnetization can be used for these purposes. Our letter describes a method for the optical observation of the coherently precessing magnetization in conditions when the concentration of magnons reaches the value necessary for their quantum condensation. The investigations were conducted in the out-of-plane magnetized yttrium iron garnet films. The required magnon density was achieved by magnetic resonance technique. The magneto-optical imaging method provides such important parameters of the coherent spin dynamics as the amplitude and phase distributed all over the sample. It should become an indispensable read-out tool for the upcoming quantum technologies based on the magnon Bose-Einstein condensation.

Contribution of glia cells specifically astrocytes in the pathology of depression: immunohistochemical study in different brain areas.

BACKGROUND: The contribution of glial cells to the pathophysiology of depression is an emerging research purpose. This study investigated the deficits in glial cells, specifically astrocytes in various brain regions, after the development of depression and then after voluntary running in depressed rats. MATERIALS AND METHODS: Forty-five adult male Wistar rats aged 8-10 weeks were used in the study. A depression model was generated through a forced swimming programme; voluntary running was allowed on rat running wheels; and brain sections were taken from the hippocampus, dentate gyrus (DG), medial prefrontal cortex (mPFC) and cerebellar cortex. After immunostaining with specific antibodies immuno-stain, the astrocytes, oligodendroglia and microglial cells were counted, and certain indices relating astrocytes to other glial cells were calculated. Astrocytic morphology was studied, and the optical density (OD) of glial fibrillary acidic protein (GFAP) immuno-expression was measured in different groups. RESULTS: Compared to the control group, animals in the depression group exhibited significant decreases in the mean astrocyte count in all studied brain areas, significant decreases in GFAP OD values in all areas and significantly reduced values for all glial astrocyte indices in the hippocampus, DG and mPFC. Compared to the rats in the depression group, those in the depression/exercise group exhibited significantly elevated mean astrocyte and oligodendroglia counts in all studied areas, significantly elevated GFAP OD values in all studied areas, and non-significant differences in glial astrocyte indices in the hippocampus, mPFC and cerebellar cortex. CONCLUSION: Astrocytes, rather than other glia, constitute a basis for the development and/or relief of depression.

Responses of salinity and chlorophyll-a to extreme rainfall events in the northwest Arabian Gulf: Emphasis on Shatt Al-Arab.

Recent extreme hydrological events, such as high rainfall and storms, have been linked to climate change worldwide due to their relatively uncommon trends, which are generally described as having varying frequencies and higher intensities. Similar extreme rainfall trends were observed in the northwest Arabian Gulf during the 2018-2019 season. Heavy rainfall events have triggered high discharges in the river of Shatt Al-Arab, where, prior to these events, the discharge rate has exhibited a declining trend over the past 40 years. Shatt Al-Arab provides various physical, chemical, and biological functions in the region. In this study, some recent and extensive measurements of salinity and post-processed satellite images of chlorophyll-a in the northwest Arabian Gulf were recorded to assess the response of the region to the higher discharges. The results indicated that the salinity decreased significantly during and after the rainfall events in response to the higher discharges from Shatt Al-Arab. The effects of higher discharges extended over most of Kuwait's coastline, including Kuwait Bay. The chlorophyll-a distributions doubled after the extreme events, emphasising the effects of Shatt Al-Arab. Collectively, the results indicated that the discharge from Shatt Al-Arab during the extreme event exceeded 1400 m3/s, while, in the previous seasons, it rarely exceeded 80 m3/s. The higher discharge levels of discharge would result in various changes in ecology at multiple levels due to the sudden and reversing shift in the hydro-environmental processes.

[A comparative analysis of reproducibility of the jaws centric relation determined with the use of digital technologies]. / Sravnitel'nyi analiz vosproizvodimosti tsentral'nogo sootnosheniia cheliustei s ispol'zovaniem tsifrovykh tekhnologii.

AIM: To compare the precision of centric relation (CR) assessment by various methods using digital technologies. MATERIAL AND METHODS: Determination of the CR was carried out in the clinic of prosthetic dentistry on patients with intact dentition using methods of bilateral manipulation, anterior jig, leaf gauge and device for intraoral recording of the gothic arch angle. Optical jaw impressions were obtained using the intraoral 3D scanner Trios (3Shape) and the CR registers were scanned using the laboratory scanner Prime (DOF). To evaluate the reproducibility of the CR, the computer program of 3D modeling Avantis (Russia) was used, which integrated the obtained optical impressions and digital copies of the CR registers. RESULTS: None of the methods showed 100% accuracy in CR assessment. The most stable reproducibility of the position of the mandible in the CR relative to the first registration was determined by the method using an anterior jig (of our own design) and amounted to 0.119±0.012 mm, which is significantly less than using the methods of bilateral manipulation (0.225±0.028, p≤0.05) and a leaf gauge (0.207±0.02, p≤0.05). We observed a similar mean values of the reproduction accuracy when determining the CR by recording the Gothic arch angle (0,120±0,013, p≤0.05), which also has a significantly lower value (p≤0.05) compared to other methods for CR determining.

[The precision of central jaw relationship estimation in restorative dentistry]. / Analiz pretsizionnosti opredeleniia tsentral'nogo sootnosheniia cheliustei v klinike ortopedicheskoi stomatologii.

The aim of the study was to investigate accuracy of the most frequently used methods of obtaining centric relation in clinical practice. Finding of CR was carried out in clinic of prosthodontic dentistry on a 5 patients with intact dentition using four methods that are most often used, including: bimanual manipulation, leaf gauge, using an anterior deprogrammind device, the technique of determining CR with intraoral devices recording the gothic angle. To assess the accuracy of each technique there were performed 10 registrations of the central relation by one operator (200 CR registrations), with 30 minutes' intervals between the CA determination. Analysis of the contacts in CR were carried out using a photometric method of investigation. The graphic images were downloaded in Adobe Photoshop for calculation, metric data translated into digital values. The studies above showed that the accuracy of finding CR in all methods were not ideal. It can be noted that the smallest deviation of the position of the first contact in the CR was observed with use of the anterior deprogrammind device and with the intoral gothic angle recording device. The deviation along the VO axis was 0.039±0.002 mm and 0.084±0.004 mm respectively, along the MD axis 0.043±0.002 mm and 0.054±0.001 mm, respectively. The greatest error of recording the CR was shown by bimanual manipulation Dawson technique, the deviation along the axis of the VO and MD was 0.634±0.04 mm and 0.388±0.04 mm, respectively.

Optimization of Eva Green real-time mPCR for differentiating C. jejuni/coli directly from feces.

OBJECTIVE: To develop and optimize a rapid molecular method for diagnosing campylobacteriosis directly from a clinical fecal sample and at the same time for determining the most common causing agents - C. jejuni/coli. MATERIALS AND METHODS: 38 clinical fecal samples from hospitalized patients with diarrheal syndrome were tested using a rapid immunochromatographic test. All positive samples were tested for confirmation by culturing in a microaerophilic atmosphere. The Eva Green real-time mPCR reaction of a direct fecal sample was conducted using the "IQ5TM Real-Time PCR System" apparatus. RESULTS: Out of 38 clinical fecal samples which were ICT positive, 18 strains were isolated by culture, namely, 17 of C. jejuni and 1 of C. coli. The Eva Green real-time mPCR reaction also reported 18 positive samples for Campylobacter, out of which 17 were of C. jejuni and only one of C.coli. CONCLUSION: We developed and optimized the Eva Green real-time mPCR for the detection and species differentiation of C. jejuni/coli directly from a clinical fecal sample. The molecular analysis we described has a 100% sensitivity and specificity when comparing the results obtained by it to those of the culture method, which is currently the "gold standard" in the diagnosis of campylobacteriosis (Tab. 2, Fig. 1, Ref. 6).

Coherent evolution of singlet spin states in PHOTO-PHIP and M2S experiments.

A consistent theoretical description of the spin dynamics underlying photo-PHIP (para-hydrogen induced polarization) experiments is given and validated experimentally: spectra from zero-quantum coherence (ZQC) "in-phase" and "out-of-phase" were obtained and evolution of ZQCs and the population of singlet spin state was tracked and modeled. Data from recent literature [O. Torres et al., J. Am. Chem. Soc., 2014] are reinterpreted. Advantages of using M2S sequences such as APSOC for detecting photo-PHIP are demonstrated. A sequence for 2D ZQ spectroscopy based on APSOC is proposed and the fundamental principles of ZQ spectroscopy are formulated. This investigation opens a new way to obtain information on the sign of J-couplings using ZQ spectroscopy. The proposed method is also useful to track the redistribution of the singlet spin population in various PHIP related experiments, which is essential for efficient polarization transfer to target nuclei.

Application of magnetic methods for assessment of soil restoration in the vicinity of metallurgical copper-processing plant in Bulgaria.

Copper ore mining and processing are among the most harmful anthropogenic influences for the environment and they are a subject of international and national law regulations. Recultivation of areas influenced by mining and processing industry is commonly applied and monitored in order to restore as much as possible the natural environment. In this study, environmental magnetic methods are applied in order to assess the degree of soil restoration in terms of soil development, after remediation of waste dump from Cu-processing plant. Soils developed under birch forest stands of different age (5, 15, and 25 years) as well as raw waste material were sampled along depth down to 20-30 cm. Variations in magnetic parameters and ratios obtained (magnetic susceptibility, frequency-dependent magnetic susceptibility, anhysteretic remanence (ARM), isothermal remanence (IRM), ARM/IRM100mT) suggest the presence of magnetic enhancement in the upper 0-15 cm, the thickness of this layer varying depending on the age of the forest stand. Magnetic mineral responsible for this enhancement is of magnetite type, while waste material contains a large amount of hematite, as evidenced by coercivity analysis of IRM acquisition curves and thermal demagnetization of composite IRM. Magnetic grain-sized proxy parameters suggest that magnetite particles are coarser, magnetically stable, while no or minor amount of superparamagnetic grains were detected at room temperature. A well-defined linear regression between the topsoil magnetic susceptibility and the approximate age of the forest stand provides an indication that the magnetic enhancement is of pedogenic origin. It is concluded that the observed magnetic enhancement of recultivated soils studied is linked to a combined effect of pedogenic contribution and possible additions of industrial ashes as a liming agent for soil restoration.

Cross-cultural measurement invariance of the Revised Child Anxiety and Depression Scale across 11 world-wide societies.

BACKGROUND: In order to compare estimates by one assessment scale across various cultures/ethnic groups, an important aspect that needs to be demonstrated is that its construct across these groups is invariant when measured using a similar and simultaneous approach (i.e., demonstrated cross-cultural measurement invariance). One of the methods for evaluating measurement invariance is testing for differential item functioning (DIF), which assesses whether different groups respond differently to particular items. The aim of this study was to evaluate the cross-cultural measurement invariance of the Revised Child Anxiety and Depression Scale (RCADS) in societies with different socioeconomic, cultural, and religious backgrounds. METHODS: The study was organised by the International Child Mental Health Study Group. Self-reported data were collected from adolescents residing in 11 countries: Brazil, Bulgaria, Croatia, Indonesia, Montenegro, Nigeria, Palestinian Territories, the Philippines, Portugal, Romania and Serbia. The multiple-indicators multiple-causes model was used to test the RCADS items for DIF across the countries. RESULTS: Ten items exhibited DIF considering all cross-country comparisons. Only one or two items were flagged with DIF in the head-to-head comparisons, while there were three to five items flagged with DIF, when one country was compared with the others. Even with all cross-culturally non-invariant items removed from nine language versions tested, the original factor model representing six anxiety and depressive symptoms subscales was not significantly violated. CONCLUSIONS: There is clear evidence that relatively small number of the RCADS items is non-invariant, especially when comparing two different cultural/ethnic groups, which indicates on its sound cross-cultural validity and suitability for cross-cultural comparisons in adolescent anxiety and depressive symptoms.

First fast-ion D-alpha (FIDA) measurements and simulations on C-2U.

The first measurements of fast-ion D-alpha (FIDA) radiation have been acquired on C-2U, Tri Alpha Energy's advanced, beam-driven field-reversed configuration (FRC). These measurements are also forward modeled by FIDASIM. This is the first measurement and simulation of FIDA carried out on an FRC topology. FIDA measurements are made of Doppler-shifted Balmer-alpha light from neutralized fast ions using a bandpass filter and photomultiplier tube. One adjustable line-of-sight measured signals at eight locations and eight times during the FRC lifetime over 26 discharges. Filtered signals include only the highest energy ions (>6 keV) and share some salient features with the FIDASIM result. Highly Doppler-shifted beam radiation is also measured with a high-speed camera and is spatially well-correlated with FIDASIM.

Fast imaging diagnostics on the C-2U advanced beam-driven field-reversed configuration device.

The C-2U device employed neutral beam injection, end-biasing, and various particle fueling techniques to sustain a Field-Reversed Configuration (FRC) plasma. As part of the diagnostic suite, two fast imaging instruments with radial and nearly axial plasma views were developed using a common camera platform. To achieve the necessary viewing geometry, imaging lenses were mounted behind re-entrant viewports attached to welded bellows. During gettering, the vacuum optics were retracted and isolated behind a gate valve permitting their removal if cleaning was necessary. The axial view incorporated a stainless-steel mirror in a protective cap assembly attached to the vacuum-side of the viewport. For each system, a custom lens-based, high-throughput optical periscope was designed to relay the plasma image about half a meter to a high-speed camera. Each instrument also contained a remote-controlled filter wheel, set between shots to isolate a particular hydrogen or impurity emission line. The design of the camera platform, imaging performance, and sample data for each view is presented.

Synthesis of magnetic silica nanomarkers with controlled physicochemical properties.

Magnetic markers which can be detected with an extremely high sensitivity with the method of magnetic particle quantification (MPQ) were synthesized. Using a controlled Stober reaction, a set of magnetic silica markers of different sizes and zeta potentials was obtained. The use of a carboxymethyl dextran polymer to stabilize the magnetite particles during the synthesis made it possible to substantially reduce the detection limit of the obtained construct, which opens up new opportunities for creating effective diagnostic nanoagents.

Clostridium perfringensα-toxin interaction with red cells and model membranes.

The effects of Clostridium perfringensα-toxin on host cells have previously been studied extensively but the biophysical processes associated with toxicity are poorly understood. The work reported here shows that the initial interaction between the toxin and lipid membrane leads to measurable changes in the physical properties and morphology of the membrane. A Langmuir monolayer technique was used to assess the response of different lipid species to toxin. Sphingomyelin and unsaturated phosphatidylcholine showed the highest susceptibility to toxin lypolitic action, with a two stage response to the toxin (an initial, rapid hydrolysis stage followed by the insertion and/or reorganisation of material in the monolayer). Fluorescence confocal microscopy on unsaturated phosphatidylcholine vesicles shows that the toxin initially aggregates at discrete sites followed by the formation of localised "droplets" accumulating the hydrolysis products. This process is accompanied by local increases in the membrane dipole potential by about 50 (±42) mV. In contrast, red blood cells incubated with the toxin suffered a decrease of the membrane dipole potential by 50 (±40) mV in areas of high toxin activity (equivalent to a change in electric field strength of 10(7) V m(-1)) which is sufficient to affect the functioning of the cell membrane. Changes in erythrocyte morphology caused by the toxin are presented, and the early stages of interaction between toxin and membrane are characterised using thermal shape fluctuation analysis of red cells which revealed two distinct regimes of membrane-toxin interaction.

Does the Strengths and Difficulties Questionnaire - self report yield invariant measurements across different nations? Data from the International Child Mental Health Study Group.

AIMS: This study evaluated the measurement invariance of the strengths and difficulties questionnaire (SDQ) self-report among adolescents from seven different nations. METHODS: Data for 2367 adolescents, aged 13-18 years, from India, Indonesia, Nigeria, Serbia, Turkey, Bulgaria and Croatia were available for a series of factor analyses. RESULTS: The five-factor model including original SDQ scales emotional symptoms, conduct problems, hyperactivity-inattention problems, peer problems and prosocial behaviour generated inadequate fit degree in all countries. A bifactor model with three factors (i.e., externalising, internalising and prosocial) and one general problem factor yielded adequate degree of fit in India, Nigeria, Turkey and Croatia. The prosocial behaviour, emotional symptoms and conduct problems factor were found to be common for all nations. However, originally proposed items loaded saliently on other factors besides the proposed ones or only some of them corresponded to proposed factors in all seven countries. CONCLUSIONS: Due to the lack of a common acceptable model across all countries, namely the same numbers of factors (i.e., dimensional invariance), it was not possible to perform the metric and scalar invariance test, what indicates that the SDQ self-report models tested lack appropriate measurement invariance across adolescents from these seven nations and it needs to be revised for cross-country comparisons.

Role of personal and family factors in alcohol and substance use among adolescents: an international study with focus on developing countries.

Most studies examining adolescent alcohol and substance use or abuse hardly include samples from developing countries. To bridge some gap, the prevalence and associated social correlates of alcohol and substance use and abuse was examined among a cohort of school-going adolescents sampled from seven developing countries. Alcohol and substance abuse was measured using the CRAFFT instrument, independent socio-demographic correlates were determined using regression models. A total of 2454 adolescents completed the study, among which 40.9% reported using either alcohol or at least one other substance during the previous 12 months. This was mostly alcohol (37.8%), followed by marijuana/hashish (8.6%) and other substances (8.1%). Among the adolescents who reported using at least one substance, 45% (18.3% of total sample) had CRAFFT scores indicative of problematic or hazardous substance use. Several personal and family factors were independently associated with use/abuse, and the modifiable nature of these factors calls for appropriate intervention strategies.

Wave chaos in a randomly inhomogeneous waveguide: spectral analysis of the finite-range evolution operator.

The problem of sound propagation in a randomly inhomogeneous oceanic waveguide is considered. An underwater sound channel in the Sea of Japan is taken as an example. Our attention is concentrated on the domains of finite-range ray stability in phase space and their influence on wave dynamics. These domains can be found by means of the one-step Poincare map. To study manifestations of finite-range ray stability, we introduce the finite-range evolution operator (FREO) describing transformation of a wave field in the course of propagation along a finite segment of a waveguide. Carrying out statistical analysis of the FREO spectrum, we estimate the contribution of regular domains and explore their evanescence with increasing length of the segment. We utilize several methods of spectral analysis: analysis of eigenfunctions by expanding them over modes of the unperturbed waveguide, approximation of level-spacing statistics by means of the Berry-Robnik distribution, and the procedure used by A. Relano and coworkers [Relano et al., Phys. Rev. Lett. 89, 244102 (2002); Relano, Phys. Rev. Lett. 100, 224101 (2008)]. Comparing the results obtained with different methods, we find that the method based on the statistical analysis of FREO eigenfunctions is the most favorable for estimating the contribution of regular domains. It allows one to find directly the waveguide modes whose refraction is regular despite the random inhomogeneity. For example, it is found that near-axial sound propagation in the Sea of Japan preserves stability even over distances of hundreds of kilometers due to the presence of a shearless torus in the classical phase space. Increasing the acoustic wavelength degrades scattering, resulting in recovery of eigenfunction localization near periodic orbits of the one-step Poincaré map.

The effect of oxidative stress on the membrane dipole potential of human red blood cells.

The membrane dipole potential (ψ(d)) is an important biophysical determinant of membrane function and a sensitive indicator of lipid organisation. In this study we have used the environmentally sensitive probe di-8-anepps to explore the effects of oxidative stress on the membrane dipole potential of human erythrocytes. Cells suspended in 0.15mM phosphate buffered saline containing 0.1mg/ml albumin maintained a mean value for ψ(d) of 270 (±20) mV over the course of 1hour. In the presence of 0.4mM cumene hydroperoxide there was an increase in ψ(d) of 14 (±7)%, accompanied by a decrease in cell diameter of ~14 (±2)%. Exposure of the cells to 0.4mM hydrogen peroxide caused ψ(d) to decrease by 13 (±8)% at the centre of the cell and 8 (±5)% at the edge whilst the diameter remained constant. In both cases the changes were equivalent to a change in transmembrane electric field of a magnitude of ~10MVm(-1), sufficient to influence membrane function. Raman microspectrometry supported the conclusion that cumene exerts its effect primarily on membrane lipids whilst hydrogen peroxide causes the formation of spectrin-haemoglobin complexes which stiffen the membrane.