bluuebunny/crossref_metadata_2025 huggingface dataset:
Young adults’ pathways of negating harms and pleasure related to recreational poly-drug use: A complex balancing act
Authors: Murray Hayley
Published: January 2023

Background: This paper examines the drug use and harm reduction practices of a subset of young adults in the Greater London area who engage in recreational poly-drug use. It traces their complex relationships with three popular party drugs – MDMA/ecstasy, cocaine, and alcohol – and explores the difficulties of balancing the harms and benefits within the context of situated poly-drug use practices.
Method: Longitudinal qualitative interviews with 31 young adults, aged 22 to 25. Three phases of thematic, semi-structured interviews were conducted from February 2018 to April 2019.
Results: This paper describes participants’ relationships to both MDMA and cocaine and the various ways they balance the risks and pleasures associated with these drugs. Participants appeared to succeed in balancing the two with MDMA, based largely on effective harm reduction messaging. With their cocaine use, however, we see a rise in challenges complicating this balancing act. Framed by ‘harm reduction from below,’ this paper shows that participants generally see cocaine’s adverse effects as less physically and mentally harmful than those of MDMA and this is reflected in their drug use choices. But the perception of cocaine’s relative safety has consequences, particularly when we consider the drug’s normalization and acceptability in spaces where it is frequently co-consumed with alcohol. In light of their consistent co-consumption of cocaine and alcohol, this pathway analysis suggests that participants’ efforts to reduce harm in one instance could create more harm and long-term negative effects in another. And as a result, participants struggle to bring the risk and pleasure of this co-consumption into balance.
Conclusion: Further exploration on both young peoples’ evolving motivations of drug choice and use and on how young people navigate the nuances of balancing acts within their poly-drug use would be a helpful contribution to advancing field of harm reduction. An emphasis on the psychological and physical risks of the prevalent practice of co-consuming cocaine and alcohol are also encouraged.
Understanding the Passive Behaviour of Low-Chromium High-Strength Hybrid Steel in Corrosive Environments
Authors: Örnek Cem , Payam Beste , Gloskovskii Andrei , Kazmanlı Kürşat , Derin Bora , Ürgen Mustafa , Avcı Burçak , Ooi Steve
Published: January 2023

We examined the unusual passive character of Hybrid steel in de-aerated sulfuric acid and aqueous sodium chloride solutions by benchmark corrosion and surface analytical tests in combination with CalPhaD-based thermochemical modelling. The electrochemical potentiodynamic polarization measurements have shown that Hybrid steel possesses all characteristic features of what makes steel stainless, such as passivity, breakdown and pitting, similar to standard low-alloyed stainless steel. Synchrotron hard X-ray photoelectron spectroscopy (HAXPES) analysis revealed that the stainless nature of Hybrid steel is achieved by a dynamically protective nanometre-sized passive film consisting of Fe, Cr, Ni, and Al oxides. The thermodynamic calculations showed that the surface oxide composition is Fe2O3•FeCr2O4•NiO•Al2O3, which changes structure, fraction and existence over electrochemical polarization. It has become understood that the presence of Al and Ni supports Cr in forming a spontaneously passive and hence protective surface, yielding exceptional corrosion resistance in acidic and chloride-containing aqueous solutions. The surface oxide could withstand breakdown and remain passive/repassivated even after transpassing the Cr(III)-to-Cr(VI) redox potential. While Cr is the prime passivating agent, an adverse effect of Cr was seen on grade 304 and 420 stainless steel when Cr(VI) species were released, savaging the passive film due to extensive interfacial pH reduction. However, among all tested stainless steels, Hybrid steel could repassivate due to the remaining and enriching Al and Ni oxides providing superior anodic passivation. Our work demonstrates that delicate alloying and microstructure engineering can design sustainable stainless steel with optimum high-strength properties without needing the well-known Cr threshold concentration of 10.5 per cent.
Astrocytoma and IDH1-Wildtype Glioblastoma (GBM) Cells Colonize Tumor Vessels and Deploy Vascular Mimicry
Authors: Maraqah Haitham H. , Abu-Asab Mones S. , Lee Han Sung , Aboud Orwa
Published: January 2023

Gliomas are the most prevalent type of malignant brain tumors with a very dismal prognosis. Angiogenesis in glioma has recently gotten more attention and its molecular aspects have been published; however, these were not complemented with ultrastructural evidence. Our ultrastructural examination of glioma vessels reveals several unique and critical features related to their mechanisms of progression and metastasis strategy. The detailed ultrastructural survey of 18 IDH1-wildtype glioblastomas (GBM) and 12 IDH1-mutant High-grade gliomas indicated that tumor vessels of both types had undergone deformities such as the thickening of the vessel wall (VW) and proliferation of the basement membrane, contour distortions, abnormal and discontinuous basal lamina, tumor cells’ invasion and colonization of VW, disappearance of endothelial cells (ECs), pericytes, and smooth muscle cells, as well as the formation of a continuous ring of tumor cells attached to the luminal side of VW in numerous cases. The latter feature is a clear sign of vascular mimicry (VM) that was previously suggested in gliomas but never shown by TEM. Additionally, the vascular invasion was carried out by a large number of tumor cells and was accompanied by the accumulation of tumor lipids in the vessels’ lumina and VWs; these two features are distinct for gliomas and may alter the course of the clinical presentation and overall prognosis. This raises the issue of how to specifically target tumor cells involved in vascular invasion in order to optimize prognosis and overcome these mechanisms employed by the tumor cells.
No lukewarm diatom communities - the response of freshwater benthic diatoms to phosphorus as basis for a new Phosphorus Diatom Index (PDISE)
Authors: Kahlert Maria , Fölster Jens , Tapolczai Kálmán
Published: January 2023

In the present study, we developed a new Swedish phosphorus diatom index (PDISE) to improve the poor fit of existing indices to match the needs of water managers to detect and mitigate eutrophication. We took advantage of a large amount of data (820 Swedish sites) collected in recent years. During our work, we found an unexpected bimodal response of the diatom taxa to phosphorus, with the taxa clustering into either an assemblage with a low, or with a high site-specific averaged optimum comprised of the diatom taxa optima. We could not find a characteristic diatom assemblage for sites with intermediate TP-site-specific averaged optima. To our knowledge, this bimodal community response has not been shown earlier. We found that the PDISE responded better than the currently used TDI and IPS to changes in TP concentrations, and thus should replace the TDI in the Swedish standard method. The modeled sensitivity values (expressed as categories) for TP were different compared to the TDI for most of the taxa included in the index development, indicating that the realized niche for these morphotaxa was different between Sweden and the UK where the TDI was developed originally. The correlation of the PDISE to TP was among the highest reported for other diatom nutrient indices globally, thus we believe that it might be worth to test it for other bioregions with similar geography and climate.
Low-loss Stable Storage of X-ray Free Electron Laser Pulses in a 14 m Rectangular Bragg Cavity
Authors: Margraf Rachel , Robles River , Halavanau Aliaksei , Krzywinski Jacek , Li Kenan , MacArthur James , Osaka Taito , Sakdinawat Anne , Sato Takahiro , Sun Yanwen , Tamasaku Kenji , Huang Zhirong , Marcus Gabriel , Zhu Diling
Published: January 2023

We present an experimental demonstration of a stable, low-loss, large x-ray cavity operating at 1.2 Angstrom wavelength. The cavity consists of 4 high reflectivity single crystal diamond Bragg mirrors arranged in a rectangular configuration with a design round trip distance of 14.2 m. Femtosecond x-ray laser pulses from an x-ray free electron laser were coupled into the cavity via a transmission phase grating. The cavity round trip efficiency and lifetime were characterized quantitatively, indicating close to the theoretical optical performance. By introducing focusing optics, we show that a stable cavity mode can be trapped within. The direct observation of sustained stable x-ray circulation provides the most direct evidence to date that cavity-based x-ray free electron lasers and other cavity-based hard x-ray systems are feasible.
Root aphid (Aploneura lentisci) population size on perennial ryegrass is determined by drought and endophyte strain
Authors: Hewitt Katrin G. , Hofmann Rainer W. , Ball Oliver J. , Cox Neil , Bryant Racheal H. , Finch Sarah C. , Popay Alison J.
Published: January 2023

Climate change is anticipated to lead to an increase in the occurrence and intensity of drought and fluctuations in insect cycles that will challenge modern pasture systems. Feeding by root aphids such as Aploneura lentisci Pass. can be a significant challenge to pastures. These below-ground living aphids are commonly found in New Zealand and Australia, feeding year-round on the roots of graminaceous plants such as perennial ryegrass (Lolium perenne L.). Some strains of the fungal endophyte Epichloë festucae var. lolii in perennial ryegrass can provide protection against root aphids and greater resilience under drought, contributing to higher persistency and growth than endophyte-free plants. However, the interaction between insect pressure and drought is not understood. This study examined the effect of drought on root aphid populations and plant performance in perennial ryegrass plants relative to endophyte status (+/-) and endophyte strain (AR37, NZCT) in a glasshouse experiment. Plants were cloned across the drought and well-watered treatments and half of the plants were inoculated with root aphids while half of the plants were treated with insecticide. Aphid populations were significantly higher in drought-stressed than in well-watered plants in both endophyte-infected and endophyte-free treatments. This resulted in reduced above and below ground plant growth. Our results suggest that root aphids are likely able to exploit the higher availability of amino acids in the plant sap of drought-exposed plants. This study provides evidence that climate change-mediated impacts of root aphids could reduce production in perennial ryegrass-dominant pastures. However, field trials would be necessary to determine whether this effect is seen in situ, where numerous additional factors will be operating at the same time.
Synthesis and Investigation of Superparamagnetic Nano-structured Fe3O4 (Magnetite) Powder Using Co-Precipitation Method
Authors: Saraçoğlu Mert , Bakırdöven Utku , Arpalı Handenur , Gezici Utku Orçun , Timur Servet
Published: January 2023

Superparamagnetic Fe3O4 nanoparticles have potential biomedical applications, but their synthesis can be challenging and costly. In this study, we present a simple and facile method for synthesizing these nanoparticles via the co-precipitation method. The pH and stabilizer concentration were optimized to obtain Fe3O4 nanoparticles with superparamagnetic characteristics and aggregated morphology in high purity. X-ray diffraction analysis revealed that the maximum magnetite formation was achieved at a pH of 12.5. Scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM) were used to characterize the morphological and magnetic properties of the synthesized powders, respectively. The results showed that the synthesized particles were micrometer-sized, composed of nanoparticles ranging from 50 to 110 nm in size, and exhibited superparamagnetic behavior with a value of 40 emu/g. The superparamagnetic behavior was attributed to the presence of nanosized crystallites and nanoparticles in the aggregated structure rather than monodisperse particles. Overall, the co-precipitation method presented in this study offers an easy, non-toxic, and fast method for synthesizing Fe3O4 nanoparticles, which may be suitable for industrial-scale production.
Vulnerability and Livelihood Adaptation Strategies of Small Island Fishers under Environmental Change: A Case Study of the Barrang Caddi, Spermonde Islands, Indonesia
Authors: Suadi  , Husni Amir , Nissa Zulfa , Trialfhianty Tyas Ismi , Ekantari Nurfitri , Mustafa Muhammad Dalvi
Published: January 2023

The changing climate brings various challenges to the fisheries industry, especially to those who depend their livelihood on fish in the small island. Through selective adaptation and mitigation strategies, many households may survive facing the unpredicted climate and weather conditions. Here we study how a small-scale fishers household in Indonesia struggled and searched their ways to face climate change which often resulted in a decrease in catch and income. Using a collective method of quantitative and qualitative, the study showed that the livelihood vulnerability level of Spermonde fishers is 0.56 (highly vulnerable). Three adaptation mechanisms such as ecological, economic and social, were discovered. The fishers often change their fishing ground location and add more fishing gear to catch the declining stock of fish or to make it easier for them to fish in the unpredicted weather. They used an ‘intensification’ strategy in dealing with climate change effects. This strategy is chosen due to the limited capital they have and a full dependency on the natural resources (fish) as their main source of food and income.
Effects of the COVID-19 Pandemic on Participation in Physical Activity of Individuals with Autism Spectrum Disorder: The True-Life Experiences of Parents
Authors: SAROL Halil , DURMUŞ Kübra , GÜRKAN Rıfat Kerem
Published: January 2023

Introduction: The COVID-19 pandemic rapidly spread throughout the whole world and negatively affected individuals’ participation in physical activity. In this context, the purpose of the research is to investigate the effects of the COVID-19 pandemic on the participation in physical activity of individuals with Autism Spectrum Disorder (ASD) from the perspective of their parents.Method: Ten parents (6 mothers and 4 fathers) with children diagnosed with ASD constituted the sample group for the research designed by the phenomenological qualitative research method. A semi-structured interview form and a personal information form were used as data collection tools. The data analysis was performed using the content analysis method.Findings: In the direction of the findings obtained from the research, four inclusive themes were determined. These are a) the effects of the pandemic on life; b) the difficulties encountered during the period of the pandemic; c) the necessity of physical activity; and d) the changing events. Under these themes, there are 12 sub-themes in total.Discussion: The parents expressed that the practices performed for the sake of decreasing the propagation rate of the virus had negatively affected especially the education, parent relationships, and active lifestyles of children with ASD. According to the parents, the physical activity habits of children with ASD significantly changed, and usually, home-based events were performed during the restrictions. The parents specified that they had understood how extremely important the participation in physical activity of children with ASD was during the period of the pandemic.
NANOSTRUCTURED CURCUMIN WITH CHOLINE AND GERANIC ACID IONIC LIQUID (CAGE-IL): POTENTIAL FOR INCORPORATION INTO PHARMACEUTICAL GEL FORMULATIONS
Authors: Vila Marta , Boscariol Rodrigo , Balcão Victor
Published: January 2023

Curcumin, a phytochemical, exhibits several biological properties and has been studied for the treatment of psoriasis. To facilitate its transdermal permeation, permeation enhancers such as choline and geranic acid ionic liquid (CAGE-IL) have been studied. From this perspective, the research effort entertained herein aimed at developing and evaluating the stability of an emulsion prepared with curcumin (phytochemical from Curcuma longa L.) and locust bean gum (extracted from the seeds of the carob tree, Ceratonia siliqua), with CAGE-IL as a facilitator of transdermal permeation. Stability studies were carried out for six months, with analyses being performed at time intervals of 0 (24 h), 30, 60, 90, and 180 days. The samples were kept at 40 ± 2 °C, with 75 ± 5% relative humidity (RH). The parameters analyzed were morphological characteristics, pH (5.8-6.0), and spreadability. The samples were shown to be stable during the timeframe studied, maintaining adequate physicochemical characteristics and meeting quality specifications for cutaneous applications. CAGE-IL, in addition to facilitating permeation of the active substance, also favored the formation of a stable emulsion encompassing nanosized particles (134.3 ± 2.6 nm) in a simple fashion and with only a few components.
Collective deliberation or just the state (in)action: how do we change the hydrodiplomacy landscape in South Asia?
Authors: Hazarika Natasha , Barua Anamika , Vij Sumit , Deka Arundhati , Salame Lena
Published: January 2023

Hydrodiplomacy in South Asia is in a nascent stage, primarily focusing on data exchange and limited state-to-state interactions, leaving aside an array of organic approaches to understand the facets of water diplomacy and governance. This perspective piece is based on a series of webinars to identify ways to bridge these gaps in hydrodiplomacy in South Asia, highlighting the merit of multi-track diplomacy for embracing the plurality of interests and decision-making. The piece concludes that it is pertinent to build capacities for improving science-media communication, acknowledging and strategizing power asymmetry, and implementing international water law to guide water diplomacy.
Groundwater quality assessment using the WQI and GIS mapping: Suitability for drinking and irrigation usage in the Sirdala block of Nawada district
Authors: Kumar Abhishek , Maurya Nityanand Singh
Published: January 2023

In the present study, the suitability of groundwater for drinking and irrigation purpose were analyzed. A total of 65 groundwater samples were collected and analyzed for relevant water quality parameters from Sirdala block of Nawada district Bihar (India). To estimate the WQI for the drinking purpose, various parameters such as pH, TDS, TH, AS and major ions (Ca2+, Mg2+, Na+, K+, Cl−, F−, HCO3−, NO3−, SO42−) were considered. The WQI for irrigation, various irrigation indices namely soluble sodium percent (Na%), sodium adsorption ratio (SAR), residual sodium bicarbonate (RSCB), permeability index (PI), magnesium hazards ratio (MHR), Kelly's ratio (KR), potential salinity (PS), Cl−: HCO3−, Mg(2+): Ca(2+) and Na+: Ca(2+) were employed and discussed in addition with Wilcox and USSL diagram. Plots, namely Gibbs ratio and Piper diagram, were used to understand chemical characteristics of groundwater. The WQI for drinking purpose was observed between 57.67 and 929.90 in which most samples (70.76%) were unsuitable for drinking. However, the WQI for irrigation purpose varied from 87.88 to 434.67 in which 50% of samples were suitable. Gibb's plots determined in this study reveal that evaporation-precipitation was the dominant factor that influences hydrochemistry. Piper plots suggest that Na-HCO3− water type was major hydrochemical facies in groundwater.
Determination of pollution status of Nilüfer river by water and bottom sediment analysis
Authors: Aşik Barış Bülent , Özsoy Gökhan
Published: January 2023

This study aims to evaluate the Nilüfer river in terms of water quality standards. Bottom sediment and water samples were taken from six different locations. The analysis of the physicochemical parameters of water compared with FAO for irrigation water quality standards. In addition, the SAR (sodium adsorption ratio), % Na, MAR (magnesium adsorption ratio), RSC (residual sodium carbonate), KR (Kelley's ratio) and % PI (permeability index) parameters were evaluated in water samples. The bottom sediment pollution situation was evaluated in terms of pollution index such as TEC (threshold effect concentration) and PEC (probable effect concentration). According to the results of the study, the irrigation water classes of the samples were determined as C2S1 and C3S1. Especially, sample sites S4, S5 and S6 were not suitable for irrigation in terms of RSC, KR. The bottom sediment exceeded the TEC and PEC limit values in terms of Zn, Cu, Cr and Ni contents. This may cause adverse effects on the majority of sediment-dwelling organisms.The use of alternative water sources should be preferred. The river can be used for irrigation with precaution but extensive treatment is required before use for irrigation purposes to prevent adverse public health effects.
Full-wave 2D modeling of helicons propagation and absorption in the spherical tokamak Globus-M2
Authors: Irzak M. A.  , Nechaev S. A.
Published: January 2023

Numerical modeling of propagation and absorption of fast waves (helicons) with frequency 200MHz in 2D inhomogeneous plasma of the spherical tokamak Globus-M2 was carried out with 2D full-wave code. Toroidal effects, poloidal magnetic field and the actual shape of the flux surfaces were taken into account. The full wave electric field and RF power absorption profiles were computed by solving plasma wave equation with electron Landau damping term. The modeling demonstrated a fairly high efficiency of helicons absorption in the bulk plasma within a wide range of experimental parameters. The waves propagate to the inner regions of the plasma column and are mainly absorbed there; less than 20% of RF energy returns back to the plasma periphery. Keywords: high temperature plasma, nuclear fusion, tokamak, high frequency plasma waves, helicons, plasma wave equation, full-wave code.
An investigation of reading thermal images processes by a thermal image receiver made in the image intensifier tube architecture
Authors: Grevcev A. S.  , Zolotukhin P. A.  , Il’ichev E. A.  , Petrukhin G. N.  , Popov A. V.  , Rychkov G. S.
Published: January 2023

The results of calculations of electric fields, potentials, and trajectories of photoelectrons calculations of single-channel dual-spectral thermal imager, implemented in the IIT architecture are presented. The values of the optimal potentials on the control electrodes (microchannel plate, reading electrode, and photocathode) that form a picture of the images of objects and ensure the correct reading of the potential relief from the surface of the sensor-converter pyroelectric film of the image thermal receiver under discussion are determined. Keywords: image intensifier tube, spontaneous polarization, a pyroelectric sensor, photocathode, photoelectronic emission, thermal object image receiver, secondary electron emission.
Modelling of three-ion ICRF heating scenario for tokamak Globus-M2
Authors: Korepanov P. A.  , Bakharev N. N.  , Gusakov E. Z.  , Dyachenko V. V.
Published: January 2023

The goal of this paper is to assess the possibility of using a new three-ion ICRF heating scheme on the spherical tokamak Globus-M2. In the first place, the operating frequencies and positions of cyclotron harmonics were found. Matching with frequency band of RF system of Globus-M2 was made. The absorption of electromagnetic waves was modeled using a one-dimensional full-wave code. Since the appearance of high-energy particles is expected in the three-ion ICRF scheme of heating special attention is paid to a comparing the estimates for generated particles energies with their confinement in tokamak Globus-M2. Keywords: nuclear fusion, tokamak, high temperature plasma, Globus-M, ICRF heating, three-ion ICRF, H-D-3He plasma.
Spectral emissivity of technical titanium near the melting point
Authors: Kosenkov D.V.  , Sagadeev V.V.
Published: January 2023

An experimental study of the normal spectral emission ability of technical titanium grade VT1-00 in the melting region was carried out. The scheme of the upgraded direct vision radiometer with replaceable narrow-band dispersion filters of the spectral range 0.69-10.9 μm. is given. The estimation of the possibility of calculating the emission capacity of titanium according to electromagnetic theory is carried out.. Keywords: normal spectral emissivity, melting region, wavelength, titanium.
Morphology of the surface of semipolar GaN layers during epitaxy on a nano-patterned Si substrate
Authors: Bessolov V.N.  , Konenkova E.V.  , Orlova T.A.  , Rodin S.N.  , Solomnikova A.V.
Published: January 2023

It has been studied the morphology of the surface of the semipolar gallium nitride layers synthesized on nano-patterned Si(100) or Si(113) substrates with a V-shaped or U-shaped surface profile, respectively. The morphology of the surface of the semipolar layers indicates that the different height-to-width ratio of the GaN(11-22) and GaN(10-11) blocks is associated with a higher growth rate of the GAN(11-22) face than GaN(10-11) and with different growth rates of the semipolar and polar crystal faces during the nucleation of the layer on a nano-patterned substrate. Keywords: surface morphology, semipolar gallium nitride, nano-patterned silicon substrate.
Circularly Polarized Electroluminescence of InGaAs/GaAs/CoPt Spin Light Emitting Diodes Placed in a Strong and Weak Magnetic Field
Authors: Dorokhin M. V.  , Demina P. B.  , Zdoroveyshchev A. V.  , Zaitsev S. V.  , Kudrin A. V.
Published: January 2023

A comparative study of the circular polarization degree dependences on external magnetic field was carried out in spin light-emitting diodes including semiconductor InGaAs/GaAs heterostructure and a magnetic CoPt contact and in control non-magnetic structures with an Au contact. In a weak magnetic field, the magnetic field dependence of electroluminescence circular polarization degree is similar to the magnetic field dependence of magnetization: it represents a hysteresis loop with saturation in a field of ~0.3 T. In a strong magnetic field, an additional linear contribution to the circular polarization degree is detected. This contribution is associated with the Zeeman splitting of energy levels. The magnitude of the linear contribution depends on the position of the quantum well relative to the ferromagnet/semiconductor interface. The obtained dependence is associated with the influence of the magnetic field of the inhomogeneously magnetized CoPt electrode on the spin relaxation time of carriers. Keywords: spin injection, quantum well, Zeeman splitting.
Study of NMR signals of rubidium in aqueous solutions and determination of the magnetic moments of Rb-85 and Rb-87 nuclei
Authors: Neronov Y.I.  , Pronin A.N.
Published: January 2023

The problem of increasing the accuracy of determining the magnetic moments of rubidium-85 and rubidium-87 nuclei based on the study of NMR signals of RbNO3 and RbCl solutions in water is considered. The spectral linewidth of the NMR signals from the 85Rb and 87Rb nuclei is a hundred times greater than the similar width of the signals from the nuclei for other neighboring alkaline elements of the periodic table, and such a broadening limits the possibilities for precision registration of nuclear resonance frequencies. Simultaneous registration of nuclear magnetic resonance signals from water protons and from rubidium nuclei was used in the work, which makes it possible to minimize the spread of data for the resonance frequency ratio. The ratios of the resonance frequencies of water protons and 85Rb, 87Rb nuclei were determined for aqueous solutions of RbCl and RbNO3 with concentrations from 0.5 to 2.0 mol/kg H2O. As a result, the ratios of magnetic moments μ(87Rb)/μ(85Rb)=2.0333981(2) were calculated with a relative uncertainty delta~10-7. The data on the resonance frequency ratio f(^1H)/f(87Rb) for the content of rubidium salts in water were extrapolated to zero concentrations and f(^1H)/f(87Rb)=3.0561795(2) was determined for rubidium ions surrounded by water molecules. As a result, the magnetic moments are determined μ(85Rb)=1.353067(37), μ(87Rb)=2.751324(74). The obtained results are compared with the data of previous works. Keywords: precision determination of nuclear magnetic moments, simultaneous registration of NMR signals from two types of nuclei, quantum radiophysics. Keywords: precision assessment of nuclear magnetic moments, rubidium-87 in solution and spin-spin interaction, simultaneous registration of signals from two types of nuclei, quantum radiophysics.
Thermal properties of CO-Yb-substrate nanostructures
Authors: Kuzmin М.V.  , Mittsev М.А.
Published: January 2023

Influence of adsorbed carbon monoxide molecules on the thermal properties of rare-earth metal ytterbium films of nanoscale thickness has been studied. The films are produced at room temperature by metal deposition on single-crystal silicon substrates with the Si(111) surface orientation or textured tungsten ribbons with the predominant (100) face. It is shown that the adsorbed molecules hinder evaporation of ytterbium. The strength of such hindering is dependent on the chemical nature of substrate material. It is established that the substrates affect the state of adsorbed molecules through the nanofilms. This in turn influences on the evaporation rate of nanolayer material. Keywords: thermal stability of nanofilms, surface, adsorbed molecules, carbon monoxide, ytterbium, silicon, tungsten, Auger electron spectroscopy, mass spectrometry.
Research and development of discharge free insula-tion of wires for space application
Authors: Tolstikov S. Y.  , Saenko V. S.  , Tyutnev A. P.
Published: January 2023

The present research aimed to investigate a charging of the cylindrical insulation layer of wires for space applications under the influence of isotropic electron radiation with an electron injection uniform in the volume of the dielectric. An analytical solution of the first-order differential equation resulting from the proposed charging model is obtained. A software has been developed and received state registration that allows for a complete calculation of the physical parameters of space-application wires resistant to electrification effects. The obtained results are proposed to be used for modeling and testing of wires for space applications in order to completely exclude the physical possibility of the occurrence of electrostatic discharges (ESR) of the "insulation-core" type during the operation (of the spacecraft) in orbit during geomagnetic disturbances in the Earth's magnetosphere. Keywords: electricity, bulk charging, insulation, dark conductivity, electrostatic discharge.
Crystals of the phenazine coordination polymer with the third order symmetry axis: formation, properties
Authors: Kompan M.E.  , Malyshkin V.G.  , Boiko M.E.  , Sharkov M.D.  , Sapurina I.Yu.  , Shishov M.A.
Published: January 2023

Unusual quasi-two-dimensional crystals of a regular triangular shape, self-formed in the process of obtaining a coordination polymer based on phenazine and silver, are described and studied. X-ray diffraction studies were carried out, the interplanar distance was determined, and the spectra of Raman scattering were obtained. A mechanism is proposed that can cause the appearance of triangular crystals from nuclei of hexagonal symmetry. Keywords: X-ray diffractometry, Raman scattering, phenazines - organic crystals.
The influence of temperature on electrophysical characteristics of carbon--containing polymer composites
Authors: Zyuzin A.M.  , Karpeev A.A.  , Yanzen N.V.
Published: January 2023

The influence of temperature on the electrophysical characteristics of polymer composites based on a matrix of ethylene vinyl acetate filled with carbon black (CB) is investigated. It is established that the most noticeable transformation of the temperature dependences of the resistivity rho(T) after the first heating-cooling cycle occurs in composite samples saturated with peroxide. Saturation of the composite with peroxide and the crosslinking of macromolecules leads to the N-shaped character of the dependence rho(T). The occurrence of hysteresis rho(T) and its character indicate that in the studied composites, the process of crystallization of the polymer matrix has significantly less effect on the destruction of the conductive mesh formed as a result of agglomeration of CB particles compared with the processes accompanying melting. Keywords: polymer composites, carbon black, electrical conductivity, temperature dependence.
Sensitization of ZnO nanorods by AgInS-=SUB=-2-=/SUB=- colloidal quantum dots for adsorption gas sensors with light activation
Authors: Ryabko A.A.  , Nalimova S.S.  , Mazing D.S  , Korepanov O. A.  , Guketlov A.M.  , Aleksandrova О.A.  , Maximov A. I.  , Moshnikov V.A.  , Shomakhov Z.V.  , Aleshin A.N.
Published: January 2023

A low-temperature technique for the formation of coatings based on ZnO nanorods decorated with colloidal AgInS2 quantum dots is presented. It is shown that ZnO nanocrystals and colloidal AgInS2 quantum dots with a shell of mercaptopropionic acid molecules form a heterojunction. Sensitization of ZnO nanorods with AgInS2 colloidal quantum dots to visible irradiation provides a gas analytical response of the structure to isopropyl alcohol vapor at room temperature under blue LED illumination with a peak wavelength of 460 nm. Keywords: adsorption gas sensors, photoactivation of gas sensitivity, zinc oxide nanorods, AgInS2 colloidal quantum dots, sensitization.
Pulse energy of a non-relativistic, high-current electron beam
Authors: Kiziridi P. P.  , Ozur G.E.
Published: January 2023

Energetic characteristics of a high-current electron gun with a cathode assembly based on multi-gap initiation of explosive emission by dielectric surface flashover in the mode of vacuum and gas-filled diode were investigated. It has been shown that it is better to measure high-current electron beam pulse energy using a calorimetric (thermal imaging) method than to calculate it from the waveforms of accelerating voltage and beam current onto collector (target) since the beam current values may be essentially overstated because of decay current of a dense plasma emergent under the bombardment of a collector by the beam electrons. The best efficiency of the energy transfer from the capacitive storage of the high-voltage pulsed generator supplying an electron gun was observed in the case of gas-filled diode at a moderate pressure of the working gas (argon, 0.093 Pa). Keywords: high-current electron beams, explosive emission, multi-gap initiation, dielectric surface flashover, beam pulse energy, plasma decay current, thermal imaging.
Negative current feedback in the accelerating gap in electron sources with a plasma cathode
Authors: Vorobyov M.S.  , Moskvin P.V.  , Shin V.I.  , Koval T.V.  , Devyatkov V.N.  , Doroshkevich S. Yu.  , Koval N.N.  , Torba M.S.  , Ashurova K.T.
Published: January 2023

Using the example of an electron source with a plasma cathode based on a low-pressure arc discharge with grid stabilization of the cathode/emission plasma boundary and an open anode/beam plasma boundary, a mechanism is described for increasing the electrical strength of a high-voltage accelerating gap by introducing a series negative current feedback (NCF) in the accelerating interval, which makes it possible to level out uncontrolled bursts of the beam current during its pulse. The introduction of NCF is achieved by using a special electrode in the space of the plasma emitter connected through a resistance to the anode of the arc discharge, and the main task of which is to intercept accelerated ions penetrating into the emitter from the high-voltage accelerating gap, due to which the current of electron emission from the arc discharge plasma decreases by a value proportional to the ion current in the accelerating gap. Since most sources and accelerators of electrons with plasma cathodes based on discharges of various types have a similar principle of operation, the use of this method will not only expand the limiting parameters of the generated electron beams, but also increase the stability of the operation of such electron sources, and, accordingly, beam irradiation of various materials and products. Keywords: arc discharge, plasma cathode, electron source, electron beam, ion beam, negative feedback.
Auger analysis of thallium oxide formed using a low-energy beam of oxygen ions
Authors: Ashkhotov O. G.  , Ashkhotova I. B.
Published: January 2023

The effect of irradiation with low-energy oxygen ions on the composition and some properties of the layer formed on the thallium surface has been studied. It is shown that bombardment with oxygen ions leads to the formation of a two-dimensional oxide layer, which effectively passivates the surface. Keywords: layer, spectroscopy, surface, energy, composition, bombardment.
Superfluid helium based ultracold neutron source for the PIK reactor
Authors: Serebrov A. P.  , Lyamkin V. A.  , Fomin A. K.  , Onegin M. S.
Published: January 2023

The PIK reactor at NRC "Kurchatov Institute"-PNPI is going to be equipped with a high-flux Ultra Cold Neutron (UCN) source for fundamental physics researches. The UCN source will use superfluid helium, which will make possible to achieve the density of UCN 2.2·10^3 cm-3, that has not yet been achieved anywhere in the world. The UCN source will be installed on the GEK-4 channel, which will make possible to obtain a low value of heat influx to cryogenic vessels from reactor radiation. The heat removal from the UCN source vessel will be implemented by using a heat exchanger. The calculated UCN density in the EDM spectrometer chamber at the PIK is going to be 200 cm-3, which is 20 times higher than the existing UCN densities in the world. For a new UCN source based on superfluid helium, an extensive research program has been developed in field of the physics of fundamental interactions, including the search for a nonzero neutron EDM, precision measurement of the neutron lifetime, and search for mirror dark matter. Keywords: ultracold neutrons, neutron sources, superfluid helium, neutron EDM, neutron decay.
Terahertz express diagnostics of complications caused by COVID-19
Authors: Bagraev N.T.  , Klyachkin L.E.  , Malyarenko A.M.  , Taranets K.B.
Published: January 2023

A spectrometer based on silicon nanosandwiches has been proposed to detect complications caused by COVID-19. Operating in the mode of a balanced photodetector, the silicon nanosandwich is both a source of terahertz irradiation and a receiver of reflected and/or radiated from biological tissue. It has been demonstrated that recording the current-voltage characteristics of a silicon nanosandwich made it possible to analyze changes in the thyroid gland, thereby determining the degree and nature of changes caused by the COVID-19 disease.. Keywords: silicon nanosandwich, terahertz irradiation, current-voltage characteristic, COVID-19.
Magnetic properties of edge channels of silicon nanosandwich structures with deposited DNA oligonucleotides
Authors: M.A. Fomin  , L.E. Klyachkin  , A.M. Malyarenko  , V.V. Romanov  , N.T. Bagraev
Published: January 2023

Measurements of the field dependences of the static magnetic susceptibility demonstrate de Haas-Van Alphen and Aharonov-Bohm oscillations at high temperatures and low magnetic fields in silicon nanosandwich structures (SNS). In the case of the deposition of DNA oligonucleotides into the edge channels of the SNS, a change in the oscillation period is observed. The possibilities of using the obtained data to identify the properties of DNA oligonucleotides are discussed. Keywords: THz radiation, DNA identification, de Haas-Van Alphen, Aharonov-Bohm.
Image processing algorithms in the DNA sequencer "Nanofor SPS"
Authors: Manoilov V.V.  , Borodinov A.G.  , Saraev A. S.  , Petrov A. I.  , Zarutskiy I. V.  , Kurochkin V. E.
Published: January 2023

The success of genomic sequencing is impossible without the development of information technologies and mathematical methods for data processing to establish various features in the analyzed objects (nucleic acids) and trends in their changes. The volume of experimental data in the research of the genome has grown significantly, and new methods and algorithms are required for their processing. The primary stage of processing the data of devices for genomic parallel sequencing is the evaluation of the parameters of images obtained from video cameras in the form of electrical signals. The next stage of processing is the construction of a sequence of nucleotides according to algorithms that depend on the principle of operation of the device for sequencing nucleic acids. When performing this stage, algorithms for evaluating quality indicators for all individual readings (reads) are important. One of the ways to assess quality is to use algorithms based on the k-measure analysis methodology. The calculation of the number of occurrences of k-measures during the experiment on the parallel sequencing system makes it possible to assess the reliability of the analysis. In this article, algorithms for processing genetic analyzer data are considered. Keywords: sequencing, nucleic acid, data processing, image processing.
Natural elimination of upconversion YVO-=SUB=-4-=/SUB=- : Yb, Er nanoparticles from a grape snail
Authors: Shmelev A.G.  , Nikiforov V.G.  , Zharkov D.K.  , Andrianov V. V.  , Muranova L. N.  , Leontyev A. V.  , Gainutdinov Kh. L.  , Lobkov V. S.  , Alkahtani M  , Hemmer P. R
Published: January 2023

We report on a method for detection of upconversion nanoparticles (UNPs) in biological preparations by using confocal microscopy technique. Approbation of the method was carried out by monitoring the natural excretion of an injected colloidal solution of YVO4 : Yb, Er nanoparticles (0.2 ml, containing 15 mg ANP, dosage 600 mg/kg) with sizes from 10 nm to 700 nm into the snail. The experiments showed that the animal naturally eliminated the nanoparticles from the body within three days, while the excretion rate decreased over time. The threshold of sensitivity in the experiments was equal to one nanoparticle in 1 μl. Keywords: upconversion, vanadate nanoparticles, rare earth ions, confocal microscopy, terrestrial snails.
Pitfalls" in the path of quantitative assessment of the severity of oncological lesions in diagnostic nuclear medicine
Authors: Nesterova A. V.  , Denisova N. V.
Published: January 2023

When examining patients by single-photon emission computed tomography, the distribution of a radiopharmaceutical drug in biological tissues is evaluated. An active fast-growing tumor has an increased uptake of the drug compared to healthy tissues. In recent years, there has been considerable interest in the level of activity of a radiopharmaceutical in tumor lesions, since it can be useful for monitoring the effectiveness of prescribed therapy. To obtain quantitative results, it is necessary that the applied reconstruction algorithms include the main effects that contribute to the formation of images. One of these factors is the geometric resolution of the collimator. It was expected that taking into account this effect would improve the quantitative assessment of tumor lesions in reconstructed images. However, there were "pitfalls" in the way of obtaining quantitative images. In the diagnostic images obtained taking into account the "geometric resolution of the collimator", so-called edge artifacts were observed, which manifested themselves in the form of a sharp increase in intensity of radiopharmaceutical accumulation in small tumors and as oscillations in the intensity of radiopharmaceutical accumulation at the edges in large tumors. The problem of edge artifacts casts doubt on the correctness of quantitative assessment the level of intensity of drug accumulation in tumor lesions. In this paper, the problem of edge artifacts is investigated using the method of mathematical modeling. In numerical experiments, the dependence of the quantitative estimate of the intensity of RPD accumulation on the parameters of the reconstruction algorithm was investigated for the first time. Keywords: Nuclear medicine, mathematical modeling, single-photon emission computed tomography, edge artifacts.
Determination of moisture content in vegetative cultivated plants by the method of millimeter wave spectroscopy for the tasks of increasing plant productivity
Authors: von Gratovski S. V.  , Kocherina N. V.  , Parkhomenko M. P.  , Kalenov D. S.  , Fedoseev N. A.  , Eremin I. S.
Published: January 2023

Investigation of the genetic and breeding orientation have shown that it is inefficient to study the genotype-environment (GTE) interaction in plants at the molecular level, since the GTE effect disappears without a trace on it, being an emergent property that occurs when gene products interact with labile ones during the day, weeks, months by limiting environmental factors. Such studies should be carried out for higher system levels, namely, at the next stages of life organization --- organismal, population, ecological, phytocenotic. Since the most powerful "lever" for increasing plant productivity and yield, GTE, cannot be traced at the molecular level, knowledge of the molecular structures of the genome without knowledge of the dynamics of limiting environmental factors and the interaction of gene products with them does not contribute to the creation of high technologies for ecological genetic increase in productivity and yield plants. The accumulated world experience shows that rapid methods for measuring traits in plants, which give a holistic characterization of a complex dynamic system (this is what GTE is), can be created by interdisciplinary approaches, primarily using physical measurement methods. Within this approach, the article proposes to use the method of millimeter (MM) wave spectroscopy, which is very sensitive to changes in the water supply of plant tissues for the selection of drought-resistant plants. Keywords: plant productivity, principle of background traits, moisture content, millimeter wave spectroscopy.
Influence of nanocompositions based on light fullerene derivatives on cultural plants under favorable and stress conditions of their habitat
Authors: Panova G.G.  , SEMENOV K. N.  , Artemieva A.M.  , Rogozhin E. A.  , Barashkova A. S.  , Kornyukhin D. L.  , Khomyakov Y. V.  , Balashov E. V.  , Galushko A.S.  , Vertebnyi V. E.  , Zhuravleva A. S.  , Volkova E.N.  , Shpanev A. M.  , Udalova O. R.  , Kanash E.V.
Published: January 2023

The relevance of the new forms of ecologically safe, stable in composition, in functional activity, biodegradable preparations development with a complex positive effect on plants remains high and the presented work is devoted to acquaintance with the generalized results of interdisciplinary studies for the effect on the system of soil (soil substitute) - cultivated plants by nanocompositions created based on carbon (water-soluble polyhydroxylated, carboxylated and amino acid derivatives of fullerene C60) nanostructures with additions of trace elements in certain concentration ratios. Based on the previously identified concentration ranges of the tested fullerene derivatives with a positive effect on plants when treating their seeds, introducing them into the soil, other root habitats and foliar exposure, their compositions with salts of trace elements were developed and in a series of vegetation and field experiments under controlled favorable conditions and when modeling oxidative stress caused by UV-B irradiation, deficiency of soil moisture, deficiency of nutrients, phytopathogens, as well as in the natural conditions of the Leningrad region, the main mechanisms of positive impact (regulatory on vital systems, adaptogenic, immunomodulatory, protective) of the created nanocompositions on plants and the prospects of their application in plant growing are shown. Keywords: nanocompositions, water-soluble fullerenes C60, polyhydroxylated C60, carboxylated C60, amino acid derivatives C60, soil (soil substitute) --- plant system, production process, abiotic stresses, resistance.