bluuebunny/crossref_metadata_2025 huggingface dataset:
Distinct roles of hnRNPH1 low-complexity domains in splicing and transcription
Authors: Kim Ga Hye , Kwon Ilmin
Published: December 2021

Significance

Phase separation of low-complexity (LC) domains appended to most RNA-binding proteins (RBPs) emerges as a principle underlying spatiotemporal protein recruitment. Yet, how LC domains regulate the function of RBPs in cells remains unclear. An alternative-splicing regulator, hnRNPH1, contains two LC domains (LC1 and LC2). Here, we show that phase separation of the LC1 can exert control over hnRNPH1 function in RNA-splicing possibly by facilitating interactions between hnRNPH1 and a variety of RBPs. In contrast, the LC2 lacking in vitro phase properties, is required for aberrant transcriptional activation in the context of fusion oncoproteins. These results have broad implications for understanding how phase separation contributes to distinct roles of LC domains in control of physiological as well as oncogenic functions.
Mechanistic and structural diversity between cytochrome
bd
isoforms of
Escherichia coli
Authors: Grund Tamara N. , Radloff Melanie , Wu Di , Goojani Hojjat G. , Witte Luca F. , Jösting Wiebke , Buschmann Sabine , Müller Hannelore , Elamri Isam , Welsch Sonja , Schwalbe Harald , Michel Hartmut , Bald Dirk , Safarian Schara
Published: December 2021

Significance

Bacterial aerobic respiration is a metabolic pathway that can adapt to changing environmental conditions. Most bacteria encode for two general types of terminal respiratory oxygen reductases that catalyze the reduction of molecular oxygen to water: heme-copper oxidases (HCO) and cytochrome
bd-
type oxidases. While HCO-type enzymes are conserved throughout all domains of life, cytochrome
bd
oxidases are present solely in prokaryotes. Due to their high oxygen affinity and insensitivity toward a wide range of naturally occurring HCO inhibitors, cytochrome
bd
oxidases confer bacteria with the ability to maintain aerobic respiration under hostile conditions, especially low-oxygen environments. The importance of cytochrome
bd
as a survival factor supports a key role for this enzyme as a drug target for combating infectious diseases.
The role of HIRA-dependent H3.3 deposition and its modifications in the somatic hypermutation of immunoglobulin variable regions
Authors: Yu Guojun , Zhang Yongwei , Gupta Varun , Zhang Jinghang , MacCarthy Thomas , Duan Zhi , Scharff Matthew D.
Published: December 2021

Significance

We have shown that the immunoglobulin heavy chain V region mutation in human B cells is regulated by HIRA, which is a chaperone for H3.3, and found that H3.3 plays a role in V region mutation in part through its H3.3K36me3 modification. The absence of HIRA is associated with a change in V region chromatin accessibility. HIRA depletion and expression of the H3.3G34V mutant also decreased the recruitment of several transcriptional elongation factors, including ZMYND11, which had not previously been shown to be involved in V region mutation. These and other findings extend our knowledge of the role of chromatin structure and of transcription in regulating V region hypermutation.
Single-molecule sequencing reveals a large population of long cell-free DNA molecules in maternal plasma
Authors: Yu Stephanie C. Y. , Jiang Peiyong , Peng Wenlei , Cheng Suk Hang , Cheung Y. T. Tommy , Tse O. Y. Olivia , Shang Huimin , Poon Liona C. , Leung Tak Y. , Chan K. C. Allen , Chiu Rossa W. K. , Lo Y. M. Dennis
Published: December 2021

Significance

We revealed a large population of long cell-free DNA molecules (up to 23,635 bp in length) in maternal plasma and developed an approach which leveraged the abundance of CpG sites on long molecules to deduce the tissue of origin of individual plasma DNA molecules based on single-molecule methylation analysis. We illustrated how such an approach may be utilized to achieve noninvasive prenatal testing of monogenic diseases. We also revealed a reduction in amounts of such long cell-free DNA molecules and a different end motif profile in maternal plasma DNA from pregnancies with preeclampsia. Hence, long cell-free DNA molecules represent a valuable resource of biomarker development for pregnancy-associated disorders.
Empathy-based counterspeech can reduce racist hate speech in a social media field experiment
Authors: Hangartner Dominik , Gennaro Gloria , Alasiri Sary , Bahrich Nicholas , Bornhoft Alexandra , Boucher Joseph , Demirci Buket Buse , Derksen Laurenz , Hall Aldo , Jochum Matthias , Munoz Maria Murias , Richter Marc , Vogel Franziska , Wittwer Salomé , Wüthrich Felix , Gilardi Fabrizio , Donnay Karsten
Published: December 2021

Despite heightened awareness of the detrimental impact of hate speech on social media platforms on affected communities and public discourse, there is little consensus on approaches to mitigate it. While content moderation—either by governments or social media companies—can curb online hostility, such policies may suppress valuable as well as illicit speech and might disperse rather than reduce hate speech. As an alternative strategy, an increasing number of international and nongovernmental organizations (I/NGOs) are employing counterspeech to confront and reduce online hate speech. Despite their growing popularity, there is scant experimental evidence on the effectiveness and design of counterspeech strategies (in the public domain). Modeling our interventions on current I/NGO practice, we randomly assign English-speaking Twitter users who have sent messages containing xenophobic (or racist) hate speech to one of three counterspeech strategies—empathy, warning of consequences, and humor—or a control group. Our intention-to-treat analysis of 1,350 Twitter users shows that empathy-based counterspeech messages can increase the retrospective deletion of xenophobic hate speech by 0.2 SD and reduce the prospective creation of xenophobic hate speech over a 4-wk follow-up period by 0.1 SD. We find, however, no consistent effects for strategies using humor or warning of consequences. Together, these results advance our understanding of the central role of empathy in reducing exclusionary behavior and inform the design of future counterspeech interventions.
A short binding site in the KPC1 ubiquitin ligase mediates processing of NF-κB1 p105 to p50: A potential for a tumor-suppressive PROTAC
Authors: Goldhirsh Gilad , Kravtsova-Ivantsiv Yelena , Satish Gandhesiri , Ziv Tamar , Brik Ashraf , Ciechanover Aaron
Published: December 2021

Significance

Accumulation of abnormal proteins underlies the mechanisms of numerous diseases such as malignancies and neurodegeneration. A recent development makes use of the UPS to remove such proteins. Small molecules (PROTACs) that are made of two heads—one that binds to a “universal” Ub ligase and the other that binds to the target substrate—bring the two together, which results in ubiquitination and subsequent proteasomal degradation of the target. We designed a PROTAC made of the pVHL ligase ligand and the short site of the KPC1 ligase that binds the p105 NF-ĸB precursor. The PROTAC mimics the enzymatic activity of the native KPC1 and can therefore serve as a prototype for the development of a tumor-suppressive drug.
Attitudes of Forensic Psychiatric Staff to Self-Harm Behaviors of Their Female Patients
Authors: O’Hara Daphné , Da Silva Guerreiro João , Lefebvre Julie
Published: December 2021

The management of self-harm presents a major challenge in correctional and forensic psychiatric services, especially for women offenders, among whom it is reported to be highly prevalent. Even though staff play an important role in managing self-harm, few studies have evaluated their attitudes to this behavior. In order to understand the attitudes of staff to women’s self-harm, 16 staff members working in a forensic psychiatric hospital participated in semi-structured interviews designed to explore their experience in depth. The staff members presented, on the one hand, positive attitudes expressed as empathy, sensitivity, and positive feelings but, on the other hand, negative attitudes expressed in the form of preconceived ideas and negative feelings. Differences were also noted in their perceptions of the seriousness of self-harm. Self-harm behaviors seem to have a considerable impact not only on caregivers, but also on the entire care unit. Our study supports the importance of both professional support and training for staff who are exposed to this type of behavior. Clinical and research implications are discussed.
A social theory of resilience: The governance of vulnerability in crisis-era neoliberalism
Authors: McKeown Anthony , Hai Bui Dang , Glenn John
Published: December 2021

In this paper, we set out a critical realist-informed Marxist approach to resilience, the principal argument being that the discourse is best explicated through a theoretical lens which situates its rise in the context of a neoliberal order which is undergoing a global organic crisis. Our key contribution to the literature is to show not only that extant resilience discourses ontologise vulnerability and thereby strip political discourse of the language of social struggle, but also that they provide a crisis-recovery imaginary more congenial to the interests of capital and state than to the vulnerable populations they ostensibly aim to capacitate. We conclude by joining a chorus of other scholars committed to exposing resilience as an insidious technology of the self.
Magnification and evolution biases in large-scale structure surveys
Authors: Maartens Roy , Fonseca José , Camera Stefano , Jolicoeur Sheean , Viljoen Jan-Albert , Clarkson Chris
Published: December 2021

Measurements of galaxy clustering in upcoming surveys such as those planned for the Euclid and Roman satellites, and the SKA Observatory, will be sensitive to distortions from lensing magnification and Doppler effects, beyond the standard redshift-space distortions. The amplitude of these contributions depends sensitively on magnification bias and evolution bias in the galaxy number density. Magnification bias quantifies the change in the observed number of galaxies gained or lost by lensing magnification, while evolution bias quantifies the physical change in the galaxy number density relative to the conserved case. These biases are given by derivatives of the number density, and consequently are very sensitive to the form of the luminosity function. We give a careful derivation of the magnification and evolution biases, clarifying a number of results in the literature. We then examine the biases for a variety of surveys, encompassing
galaxy surveys and line intensity mapping at radio and optical/near-infrared wavelengths.
Minimal theory of massive gravity and constraints on the graviton
mass
Authors: De Felice Antonio , Mukohyama Shinji , Pookkillath Masroor C.
Published: December 2021

The Minimal theory of Massive Gravity (MTMG) is endowed non-linearly
with only two tensor modes in the gravity sector which acquire a non-zero
mass. On a homogeneous and isotropic background the theory is known
to possess two branches: the self-accelerating branch with a phenomenology
in cosmology which, except for the mass of the tensor modes, exactly
matches the one of ΛCDM; and the normal branch which instead
shows deviation from General Relativity in terms of both background
and linear perturbations dynamics. For the latter branch we study
using several early and late times data sets the constraints on today's
value of the graviton mass μ0, finding that (μ0/H
0)2 = 0.119-0.098
+0.12
at 68% CL, which in turn gives an upper bound at 95% CL as μ0 < 8.4 × 10-34 eV. This corresponds to the strongest bound on the mass of the graviton
for the normal branch of MTMG.
Testing Primordial Black Holes
with multi-band observations
of the stochastic gravitational wave background
Authors: Braglia Matteo , García-Bellido Juan , Kuroyanagi Sachiko
Published: December 2021

The mass distribution of Primordial Black Holes (PBHs) is affected by drops in the pressure of the early Universe plasma. For example, events in the standard model of particle physics, such as the W
±/Z
0 decoupling, the quark-hadron transition, the muon and pion becoming non-relativistic, and the annihilation of electrons and positrons, cause a suppression in the Equation of State parameter and leave peaks in the PBH mass function around 10-6, 2, 60, and 106
M
☉, respectively, in the case of a nearly scale-invariant primordial power spectrum. The superposition of unresolved mergers of such PBHs results in a stochastic gravitational-wave background (SGWB) that covers a wide range of frequencies and can be tested with future gravitational wave (GW) detectors. In this paper, we discuss how its spectral shape can be used to infer properties about inflation, the thermal history of the Universe, and the dynamics of binary formation in dense halos encoded in their merger rate formula. Although many of these physical effects are degenerate within the sensitivity of a single detector, they can be disentangled by the simultaneous observation of the SGWB at different frequencies, highlighting the importance of multi-frequency observations of GWs to characterize the physics of PBHs from the early to the late time Universe.
Wavelength-tunable picosecond laser source based on filtering and amplifying broadband dissipative soliton pulse
Authors: Li Jing , Wang Chuncan , Wang Peng , Liu Pengtao , Lan Junhao , Li Hefu
Published: December 2021

A method for obtaining picosecond pulse sources with continuously tunable central wavelengths is demonstrated numerically and experimentally. A dissipative soliton (DS) mode-locked erbium-doped fiber (EDF) laser based on the nonlinear polarization rotation provides the seed pulse with a flat-top spectral profile and a 55 nm spectral bandwidth. Then it is filtered by a wavelength-tunable super-Gaussian bandpass filter and amplified by two segments of EDFs with different doping concentrations. The output DS pulse from the EDF laser can be compressed from 5.532 ps to 0.291 ps by using a single-mode fiber (SMF-28e), while the pulse energy is about 1.6 nJ. Furthermore, the about 4 ps and 6.84 nJ pulses with continuously tunable central wavelengths ranging from 1535 to 1580 nm can be obtained by amplifying the spectrally filtered pulses. The tunable picosecond pulse source based on the extra-cavity filtering method is very useful for many practical applications because of its flexible wavelength control.
Dynamics of GB-speckles with a small number of scatterers
Authors: Ulyanov Sergey , Ulianova Onega , Saltykov Yury , Zaytsev Sergey , Ulyanov Alexander , Feodorova Valentina
Published: December 2021

A method for generating dynamic GB-speckles, formed during diffraction of focused Gaussian beams by moving virtual rough surfaces, obtained for two nucleotide sequences (the ompA genes of the Chlamydia psittaci GR9 and AMK-16 strains), is proposed. The statistical characteristics of the 1st- and 2nd-order statistics of GB-speckles, formed at a small number of scattering events, are studied. The difference in the manifestation of the Doppler effect in the dynamics of GB-speckles and for speckles, formed with a small number of scatterers, produced by light diffraction on physically-existing rough surfaces and in scattering micro-streams is revealed. The problems of interference of dynamic GB-speckles are considered. A new technique for detecting individual single nucleotide polymorphism in nucleotide sequences using the interference of dynamic GB-speckles is proposed.
Chapter 1 LHAASO Instruments and Detector technology *
Authors: Ma Xin-Hua , Bi Yu-Jiang , Cao Zhen , Chen Ming-Jun , Chen Song-Zhan , Cheng Yao-Dong , Gong Guang-Hua , Gu Min-Hao , He Hui-Hai , Hou Chao , Huang Wen-Hao , Huang Xing-Tao , Liu Cheng , Shchegolev Oleg , Sheng Xiang-Dong , Stenkin Yuri , Wu Chao-Yong , Wu Han-Rong , Wu Sha , Xiao Gang , Yao Zhi-Guo , Zhang Shou-Shan , Zhang Yi , Zuo Xiong
Published: December 2021

The Large High Altitude Air Shower Observatory (LHAASO) (Fig. 1) is located at Mt. Haizi (4410 m a.s.l., 600 g/cm2, 29° 21’ 27.56” N, 100° 08’ 19.66” E) in Daocheng, Sichuan province, P.R. China. LHAASO consists of 1.3 km2 array (KM2A) of electromagnetic particle detectors (ED) and muon detectors (MD), a water Cherenkov detector array (WCDA) with a total active area of 78,000 m2, 18 wide field-of-view air Cherenkov telescopes (WFCTA) and a newly proposed electron-neutron detector array (ENDA) covering 10,000 m2. Each detector is synchronized with all the other through a clock synchronization network based on the White Rabbit protocol. The observatory includes an IT center which comprises the data acquisition system and trigger system, the data analysis facility. In this Chapter, all the above-mentioned components of LHAASO as well as infrastructure are described.
Chapter 4 Cosmic-Ray Physics *
Authors: Piazzoli Benedetto D’Ettorre , Liu Si-Ming , Volpe Domenico della , Cao Zhen , Chiavassa Andrea , Piazzoli Benedetto D’Ettorre , Guo Yi-Qing , Ksenofontov Leonid T. , Martineau-Huynh Olivier , Martraire Diane , Ma Ling-Ling , Ma Xin-Hua , Stenkin Yuri , Yuan Qiang , Zeng Hou-Dun , Zhang Shou-Shan , Zhang Yi , Zhu Hui
Published: December 2021

In the first part of this Chapter the present state of knowledge from the observations of cosmic rays between 1013 and 1020 eV is summarized. This is not intended to be a complete review, but rather a broad overview of the relevant processes involving cosmic rays, including the astrophysical environments in which they take place. This overview mainly concerns experimental results and phenomenological aspects of their interpretation, therefore experiments’ description is not given but references to the vast bibliography are provided in the text. Some attempt is made to address the most popular explanations offered by theoretical models. The second part is devoted to the description of the LHAASO performance and of its capability to provide a response to several open questions, still unanswered, concerning cosmic rays above 1013 eV, highlighting which major steps forward in this field could be taken from LHAASO observations.
Study of ion cyclotron range of frequencies heating characteristics in deuterium plasma in the Large Helical Device
Authors: Kamio S. , Saito K. , Seki R. , Kasahara H. , Kanda M. , Nomura G. , Seki T.
Published: December 2021

The characteristics of ion cyclotron range of frequencies (ICRF) minority ion heating with a hydrogen minority and deuterium majority plasma were studied by ICRF modulation injection experiments in the Large Helical Device (LHD). In recent experiments with deuterium plasma, no significant increase in the neutron emission rate due to ICRF second harmonic deuteron heating was observed. Therefore, in this study, the neutron emission rate was used to refer to the information regarding the thermal ion component. Like the results of the observations of the heating efficiencies at various minority proton ratios, the experimental results showed good agreement with the simple model simulation of ICRF wave absorption. During these experiments, the accelerated minority hydrogen ions were observed by neutral particle analyzers. The counting rates of the energetic particles were higher in the lines of sight passing through the helical ripple than across the magnetic axis, and the counting rate decreased as the minority hydrogen ion ratio increased. The dependence of the minority hydrogen ion ratio on the density of the energetic ions was consistent with the experimentally observed heating efficiencies and simulations. The heating efficiency of ICRF minority ion heating could be well explained by simple model simulation in the LHD deuterium experiment.
The influence of temperature and arsenic molecular form at crystallization stage on the InAs nanostructure growth during droplet epitaxy
Authors: Chernenko N E , Balakirev S V , Eremenko M M , Solodovnik M S
Published: December 2021

In this work, experimental studies of the influence of the arsenic molecular form (di-or tetramers) and substrate temperature on the crystallization of In/GaAs droplet nanostructures during droplet epitaxy have been carried out. We have shown the critical influence of the temperature and arsenic molecular form on the reproducibility of the characteristics of an array of self-organizing InAs nanostructures during crystallization. We also showed that a decrease in the initial In droplet size has a positive effect on the reproducibility of the parameters of the InAs nanostructures arrays. Our work also showed important role of substrate temperature at the crystallization stage.
Estimation of thermodynamic stability of isoperiodic epitaxial structures whith GaInSbAs and GaInAsP solid solutions
Authors: Danilina E M , Paschenko A S
Published: December 2021

The work studied the thermodynamic stability of GaInSbAs, GaInAsP heterosystems on different substrates. The isotherms of spinodal decomposition caused by chemical changes in the internal energy of the alloy and by elastic stresses at the layer-substrate interface are obtained with the model of quasiregular solutions. It has been found that elastic stresses lead to an expansion of the region of thermodynamic stability of isoperiodic solid solutions for GaSb substrates and a decrease in the critical temperature. The developed model can be using to selection of the technological modes and parameters of epitaxial growth.
Study of In/GaAs nanodroplet formation in conditions of non-stationary supersaturation during droplet epitaxy
Authors: Dukhan D D , Balakirev S V , Chernenko N E , Eremenko M M , Solodovnik M S
Published: December 2021

In this paper, we present the results of kinetic Monte Carlo study of the In/GaAs growth by droplet epitaxy in conditions of non-stationary vapor supersaturation. These conditions allow achievement of the independent control of size and surface density of nanostructures. The material redistribution is realized on the surface when indium deposition is interrupted and leads to a decrease in the critical thickness of droplet formation. An average droplet size increases with increase in interruption time whereas the surface density decreases. However, additional nucleation within the wetting layer can also be observed during the growth interruptions, which makes it possible to increase the surface density of droplets.
Elastic properties of porous silicon layer of hybrid SiC/Si substrates
Authors: Eremeev I A , Koryakin A A , Kukushkin S A
Published: December 2021

Elastic properties of porous silicon layer of hybrid SiC/Si substrates grown by the atomic substitution method are investigated. The feature of the growth method is the formation of the macroporous silicon layer at the SiC/Si interface during growth. The elastic properties of the layer are studied using the finite element method. The biaxial modulus of the porous silicon is obtained as a function of porosity considering the different shape of the pores and presence of thin SiC boundary layer. The presence of the pores in the silicon layer adjacent to SiC results in the decrease of the elastic moduli by about 35%. However, this leads to a negligibly small change of the substrate curvature.
Method for the modification of graphite subsurface layer to a solid mixture of SiC and graphite
Authors: Grashchenko A S , Kukushkin S A , Osipov A V , Redkov A V
Published: December 2021

We studied the interaction of molten Si and graphite surface during annealing in different atmospheres (CO, vacuum, Ar). The studies have shown that during annealing in CO atmosphere a composite material of SiC and graphite in a thick subsurface layer of the graphite is being formed, whereas at vacuum and Ar atmosphere the modified layer is either thin or absent. The composition and structure of both the composite material itself and the interface between the composite material and the graphite matrix were investigated using the methods of scanning electron microscopy and Raman spectroscopy. Studies have shown that the composite material obtained by this method has a branched fibrous structure consisting of small tubular layers of silicon carbide interspersed with large monocrystalline grains of silicon carbide of the cubic polytype, which leads to significant strengthening of the material. Thus the proposed method can be used to form a thermal protective, chemically resistant coating on graphite surface.
Effect of Yb3+doping level on the structure and spectroscopic properties of ZnO optical ceramics
Authors: Gorokhova E , Venevtsev I , Alekseeva I , Khubetsov A , Dymshits O , Basyrova L , Oreschenko E , Eron’ko S , Muktepavela F , Kundzins K. , Zhilin A , Loiko P
Published: December 2021

Zinc oxide optical ceramics with hexagonal structure doped with 0.6 –5.0 wt% Yb were fabricated by uniaxial hot pressing of commercial oxide powders at 1180 °C in vacuum. The ceramics were characterized by X-ray diffraction, SEM, EDX, X-ray and optical spectroscopy. It is shown that Yb3+ions are distributed between C-type Yb2O3sesquioxide crystals and ZnO grain boundaries. The Yb3+doping of ZnO ceramics enhances the near-band-edge emission of zinc oxide. ZnO:Yb optical ceramics are promising for optoelectronic applications.
Quantitative analysis of metastable wurtzite phase into the self-catalyzed GaP NWs
Authors: Koval O Yu , Fedorov V V , Eliseev I E , Bolshakov A D , Kirilenko D A , Burkovsky R G , Mukhin I S
Published: December 2021

In this letter, we report the growth of the self-catalyzed GaP nanowires with a high concentration of wurtzite phase by molecular beam epitaxy. Formation of rotational twins and wurtzite polymorph in vertical nanowires was observed by the developed a complex approach based on the transmission electron microscopy and X-ray diffraction method. Microstructural analysis performed by high resolution transmission electron microscopy and micro-Raman spectroscopy gives us insights on the nanowire formation mechanism and vibrational properties of nanowires with mixed crystal phase. We obtained wurtzite polytype segments with thicknesses lying in the range from several tens up to 500 nm. The results of the work open new perspectives for high phase purity phosphide NWs synthesis and its fast investigation with XRD technique using a laboratory X-Ray source.
Nanostructured electrodes for supercapacitors
Authors: Yavtushenko I O , Makhmud-Akhunov M Yu , Adamovich A A
Published: December 2021

The paper presents the results of studies on the formation of planar capacitive systems based on nanoporous anodic oxide films and a conducting polymer. According to voltammetry data, the capacity of the systems under study was determined. The structure of the porous layers was judged by impedance spectroscopy and electron microscopy.
Study of nonlinear optical phenomena in silicon nanowires
Authors: Mastalieva V A , Neplokh V , Morozov A I , Nikolaeva A A , Gudovskikh A S , Mukhin I S , Makarov S V
Published: December 2021

This work studies generation of second and third harmonics in arrays of vertically oriented silicon nanowires (SiNWs) encapsulated into a silicone membrane and separated from the growth substrate. The structures were produced by plasma-chemical etching of silicon substrate resulting in a formation of homogeneous arrays of SiNWs. Such SiNW-based membranes demonstrated efficient infrared-to-visible light conversion by generation of second and third harmonic signals visible by a naked eye. This study contributes to the development of technology of optical devices based on silicon and presents a new route for visualization of infrared radiation.
Laser-induced optical nonlinearity in a Li-rich glass
Authors: Moroz A Yu , Babich E S , Kaasik V P , Lipovskii A A , Melekhin V G , Redkov A V , Tagantsev D K
Published: December 2021

The selective crystallization of a photosensibilized lithium silicate glass after a light emitting diode (280 nm) and a nanosecond laser (355 nm) UV irradiation and subsequent heat treatment was studied. Using a focused beam of the laser allows successive drawing regions in which the formation of silver nanoparticles after 500°C heat treatment of the glass co-doped with silver and cerium ions takes place. It is shown that this treatment is a necessary step for the growth of sodium metasilicate crystals under the second thermal treatment of the glass at 600 °C, while these regions demonstrate second optical harmonic generation of 1064 nm nanosecond laser radiation.
The influence of the surface density of oriented nickel networks on the conducting electrode’s optical transparency
Authors: Nizameev I R , Nizameeva G R , Kadirov M K
Published: December 2021

This study is part of the work on the creation of a transparent conductive coating based on oriented nanonetwork and submicron nickel fibres. It is devoted to finding the optimal values of electrical conductivity and optical transparency of the developed coating. In this work, we study the transmission spectra of oriented nickel networks on a glass substrate in the UV, visible and near-IR regions at different amounts of deposited metal. An exciting feature of the coating was discovered: in the range of 950 nm and above, there is a "bend" of the transmission spectrum downward. This bend (increased absorption of radiation in the near-IR region) is observed only in the presence of nickel nanonetwork and is not typical for a pure submicron network.
Conformality of a-Si:H deposited by low temperature PECVD for solar cells application
Authors: Uvarov A V , Baranov A I , Morozov I A , Kudryashov D A , Maksimova A A , Vyacheslavova E A , Gudovskikh A S
Published: December 2021

This work is devoted to the study of the deposition of a-Si:H by the PECVD method in continuous and pulsed regime on test structures in the form of trenches with a high aspect ratio. The thicknesses of the layers obtained in these modes were investigated by the method of scanning electron microscopy. It was shown that the layers obtained in the pulsed mode, as compared with the continuous one, have better conformity.
Double slot aerosol jet printed antenna for X-band applications
Authors: Arsenov P V , Sobolev A S , Efimov A A , Ivanov V V
Published: December 2021

A double slot antenna for X-band applications was designed and aerosol jet printing technology was used to fabricate the prototype with silver nano-ink on a flexible polyimide substrate. We investigated the microwave losses of printed antennas in the range from 100 kHz to 27 GHz, obtained at sintering temperatures of 200 °C and 250 °C. Double slot X-band antennas have been calculated and measured. It was found that an operating bandwidth of the printed antenna is 10% in the region of the central frequency of 10.5 GHz. Thus, the possibility of forming antennas on flexible polymer substrates with high functional characteristics by aerosol jet printing method has been demonstrated.
Terahertz detector utilizing a SiO2/Graphene/SiO2 sandwich suspended at the feed of a planar antenna
Authors: Belikov I , Rybin M , Prikhodko A , Mikhailov D , Gayduchenko I , Shurakov A , Goltsman G
Published: December 2021

We report on the fabrication of a terahertz detector utilizing a SiO2/graphene/SiO2 sandwich suspended at the planar antenna feed. This design of the detector aims to enhance its sensitivity via weakening of the heat sink between graphene’s phonons and those of the substrate. We achieve complete suspension of the sandwich only in case of a low fill-factor of the antenna feed area. Evaluated DC parameters of the samples are consistent with those reported in the literature. The fabrication process developed is suitable for implementing the detector proposed for signal frequencies up to several terahertz.
Analysis of the possibility of creating an acoustic velocity sensor using GaN epitaxial films
Authors: Enns Y , Kazakin A , Akulshin Y , Mizerov A , Kleimanov R
Published: December 2021

This paper results in results of analyzing the possibility of creating an acoustic velocity sensor using epitaxial GaN films. Technology for the fabrication of a microelectromechanical acoustic velocity sensor was developed and a prototype of the sensor was produced. The simulation of the characteristics of the obtained acoustic velocity sensors was carried out on the basis of the measured electrical characteristics, where the sensitivity and the directional pattern were determined.
Features of the formation of the frequency of the microwave excitation signal in the quantum frequency standard on rubidium atoms - 87
Authors: Grevtseva A S , Dmitriev R A , Davydov V V , Rud V Yu
Published: December 2021

The article discusses the main disadvantages of the current design of a quantum frequency standard based on rubidium-87 atoms. The main disadvantages of the current design of the quantum frequency standard on rubidium-87 atoms are considered. It is noted that the processes associated with light shifts in the optical part contribute to the greatest instability in the long-term operation of the quantum frequency standard. A solution is proposed to improve the design of the rubidium standard. A forecast for improving its metrological characteristics is presented. The results of experimental investigations are presented.
Development of a fiber-optic microwave signal transmissionsystem for an X-band receiving module with dual frequencyconversion
Authors: Moroz A V , Davydov V V , Gubareva D V , Rud’ V Yu
Published: December 2021

The article discusses the use of double frequency conversion in the receiving module of the radar. To solve the resulting interference in the feeder paths, it is proposed to use a fiber- optic transmission system. The results of experimental investigations are presented.
Silicon carbide of 4H-SiC type Schottky diode current-voltage characteristics in small-sized type metal-polymeric package SOT-89
Authors: Sedykh S V , Rybalka S B , Demidov A A , Kulchenkov E A
Published: December 2021

The forward and reverse current–voltage characteristics of Ti/Al/4H-SiC Schottky diode type DDSH411A91 in modern small-sized (SOT-89) type metal-polymeric package have been obtained. In forward direction (current up to 2 A) on the basis of analysis it is shown that Schottky diode corresponds to the "ideal" diode with ideality factor n=1.12 and effective Schottky barrier height φB
=1.2 eV. It is shown that reverse current-voltage characteristics (breakdown voltage 1200 V) can be well approximated by mechanism of field dependence of barrier height lowering by the presence of the intermediate layer in the form of oxide on the 4H-SiC surface.
Supercapacitor with electrodes based on high-purity single-walled carbon nanotubes
Authors: Shumilin A , Gorshkov N , Fomin A , Aman A , Palis S
Published: December 2021

We studied a supercapacitor with high purity carbon paper electrodes [1] with a specific gravity of 20 g/m2. The specific capacitance of the electrode during assembly in a coin cell housing with an aqueous 6M KOH electrolyte, at a scan rate of 1 mV/s, is 52 F/g. The specific power is 195.42 W/kg and the specific energy is 0.19 W⋅h/kg at a scan rate of 100 mV/s, which is included in the region of supercapacitors in the Ragone plot.
Prospective directions for the development of microwave frequency standards for satellite navigation systems
Authors: Wang Ding , Davydov V V , Rud V Yu
Published: December 2021

The state of essential various quantum standards of GNSS frequencies for today are collected and presented, the results of analysis in the direction of modernization of time synchronization systems in global navigation satellite systems are presented. The most perspective directions of modernization of global navigation satellite systems are mentioned – the development of new atomic clocks on the mercury ions -199. The data on experimental satellite gives encouraging results.
Scanning ion-conductance microscope with modulation of the sample position along the Z-coordinate and separate Z-axial and lateral (X, Y) scanning
Authors: Zhukov M V , Lukashenko S Yu , Sapozhnikov I D , Felshtyn M L , Gorbenko O M , Golubok A O
Published: December 2021

Scanning ion-conductance microscope with independent piezoscanners in the lateral scanning plane XY and Z axis was designed and tested. For precise, fast and safe approach of the nanopipette to the sample surface, a coarse approach system based on a piezoinertial mover was used. Measurements of test periodic polymer structures were carried out using nanopipettes with an inner pipette diameter of about 100-150 nm. The optimal geometric parameters of the nanopipette were found and the resolution of the method was estimated. To increase the stability and reproducibility of SICM images, the Z-modulation of the position of the substrate with the sample was realized using a bimorph piezomembrane.
Determination of hole diffusion length in n-GaN
Authors: Arteev D S , Sakharov A V , Nikolaev A E , Zavarin E E , Lundin W V , Tsatsulnikov A F
Published: December 2021

The paper presents the derivation of a model for minority carriers collection based on the reciprocity theorem and its application for determination of hole diffusion length in n-GaN by means of photoluminescence. The estimated hole diffusion lengths at room temperature are 110 nm and 194 nm in the case of low and high excitation, respectively, which could be explained by saturation of non-radiative recombination centers in bulk GaN and at the surface with photogenerated carriers.
Internal optical loss and light-current characteristic in injection lasers
Authors: Sokolova Zinaida N , Pikhtin Nikita A , Slipchenko Sergey O , Asryan Levon V
Published: December 2021

Possibility of tailoring the light-current characteristic (LCC) shape in quantum dot (QD) lasers by varying uniformity of QDs is discussed. Making the QD ensemble less uniform results in roll-over in the LCC. The second branch in the LCC appears with making the QD ensemble even less uniform.
Output power of multilayered InGaAs/GaAs quantum well-dot microdisk lasers
Authors: Fominykh N A , Moiseev E I , Guseva Ju A , Maximov M V , Lihachev A I , Kryzhanovskaya N V , Zhukov A E
Published: December 2021

We studied the output optical power of microdisk lasers with InGaAs/GaAs quantum dots active region. An increase in the number of layers in the active region in the waveguide from 2 to 6 leads to increase in the peak output optical power due probably to increase of the gain. We also observe a corresponding increase of the threshold current due to the increase on the transparence current. The maximal optical power is achieved for structure with 6 layers at approximately 60 mA injection current. Further increase of the number of the QD layers to 10 results in increase of the threshold current and sudden drop of the output power.
Temperature stability of small-signal modulation response of WGM microlasers with InGaAs/GaAs quantum well-dots in the active region
Authors: Isaev N K , Moiseev E I , Fominykh N A , Kryzhanovskaya N V , Zubov F I , Ivanov K A , Makhov I S , Mintairov S A , Kalyuzhnyi N A , Guseva Yu A , Maximov M V , Zhukov A E
Published: December 2021

In this paper, results are presented on III-V quantum well dot microring diode lasers tested at elevated temperatures. To the best of our knowledge, the first uncooled microdisk lasers with diameter of 40 μm with 3-dB bandwidth above 2 GHz at 55°C are demonstrated.
Optimization of (p)a-Si:H/p-Si ohmic contact for solar cells
Authors: Kudryashov D A , Baranov A I , Uvarov A V , Morozov I A , Monastyrenko A O , Gudovskikh A S
Published: December 2021

In this work last results on optimization of (p)a-Si:H/p-Si ohmic contact made by PECVD method are presented. A strong effect of growth temperature and trimethylboron flow on charge carriers transport was demonstrated. An optimized (p)a-Si:H layer also was successfully applied as an emitter layer to a heterojunction solar cell fabrication where a measured open circuit voltage of 0.65 V was obtained.
A new device for autonomous space devices based on a three-component quantum variometer
Authors: Logunov S E , Davydov V V , Rud V Yu
Published: December 2021

The necessity of additional study of magnetic field variations in the magnetic transition layer, in the magnetopause, as well as in the plasma layer and in the tail of the magnetosphere in a wide range of distances from the Earth is substantiated. To obtain additional information in comparison with the studies that are being carried out in outer space at the present time, it is necessary to simultaneously monitor the magnetic field at various points in outer space. It is also necessary to register the dynamics of changes in the magnetic field in time in space by three components. To accomplish this task, a small-sized three-component quantum variometer with autonomous power supply has been developed for space devices, which can be lost in the course of short-term research. The results of the operation of a quantum variometer are presented.
Numerical simulation of effective light transmission through a photonic memory cell
Authors: Makarov M E , Sapegin A A , Minnullin R T
Published: December 2021

This paper is devoted to numerical simulation of a non-volatile photonic memory cell based on phase-change material Ge2Sb2Te5. The parameters of light propagation are presented for both crystalline and amorphous Ge2Sb2Te5 phases. The cell structure is optimized for a single TE-mode regime that is suitable for short- and long-distance communication lines.
Polarization control algorithm for QKD systems
Authors: Mekhtiev E E , Gerasin I S , Rudavin N V , Duplinsky A V , Kurochkin Y V
Published: December 2021

The crucial task for polarization-encoding fiber QKD is to compensate polarization drift occurring in a quantum channel. To solve this problem, the receiver usually uses a polarization controller. For proper operation, this device must be efficiently managed in real-time. In this work, a gradient-descent-based algorithm is proposed to solve this problem. The algorithm was implemented and tested on a QRate commercial QKD fiber system, that utilizes BB84-protocol. Low and stable QBER has been obtained during a day of continuous operation.
Simulation of double-junction III-phosphides/silicon solar cells
Authors: Rakitina A A , Gudovskikh A S
Published: December 2021

The characteristics of two-junction solar cells were calculated in this work, in which phosphides of group III are used as the top junction, and Si as the bottom junction. The following ternary phosphide compounds Ga0.52In0.48P (1.85 eV), GaPN0.02 (1.9 eV), and GaPN0.04 (1.7 eV) were considered as the active material of the top junction. The use of GaPN0.04 allowed one to reach the current matching with the bottom Si junction and an efficiency of 30% was achieved. In addition, the influence of the layer thickness, the lifetime of minority charge carriers and the electronic affinity on the efficiency of solar energy conversion were considered.
STM Light Emission and I(V) study of single gold nanoantenna
Authors: Shkoldin V A , Levedev D V , Mozharov A M , Permyakov D V , Dvoretckaia L N , Bogdanov A A , Samusev A K , Golubok A O , Mukhin I S
Published: December 2021

Hight-speed optical nanoemitters are of importance for on-chip optical data processing. A tunnel junctions can be a base for such light emitters, however such structures suffer from low quantum efficiency. One of the ways to improve efficiency of tunneling electron energy to photon generation conversion is the increase of the local density of optical states by using of optical nanoantennas. In this work, we study optoelectronic properties of single gold nanodisc with high spatial resolution. We show nonuniform distribution of electromagnetic near-fields of nanodisk, which is consistent with nanoantenna optical modes. And we demonstrate direct correlation between nanoantenna optical states and features on current-voltage characteristics of tunnel junction between metal tip and nanodisk.
Analysis of the limiting behavior of a biological neurons system with delay
Authors: Fedorov E G , Popov I Yu
Published: December 2021

In this work an analytical and numerical analysis of the limiting behaviors of a system consisting of a pair of biological neurons was carried out. In this case connection between neurons will occur with a delay. As a neuron model, the FitzHugh-Nagumo model was chosen as a model that can reproduce many dynamic behaviors of a real neuron and, at the same time, is not very complex computationally.
The effect of optogenetic activation of astrocytes on the hippocampal neurons activity
Authors: Gerasimov E I , Erofeev A I , Pushkareva S A , Bol’shakova A V , Borodinova A A , Balaban P M , Bezprozvanny I B , Vlasova O L
Published: December 2021

The method of optogenetics has spread widely in neurobiology over the past 10 years and has found extensive application in various fields of this sciences. It allows to control and regulate cellular activity with high spatial and temporal resolution. In this study, optogenetic activation was applied to astrocytes expressing ChR2. Optogenetic stimulation parameters were determined, in which the frequency of spontaneous currents of hippocampal pyramidal neurons significantly changed. In the future, it is planned to use the obtained data on the modes of optogenetic stimulation of astrocytes to normalize the functions of the hippocampus in mice-models of Alzheimer’s disease.
Model of ‘implant-host’ neural circuits in a microfluidic chip in vitro
Authors: Kolpakov V N , Pigareva Y I , Gladkov A A , Bukatin A S , Kazantsev V B , Mukhina I V , Pimashkin A S
Published: December 2021

In this study, we developed a new model of neuronal cells plating into a developed neural network to study functional integration using microfluidic methods. The integration was modeled in a three-chamber microfluidic chip by growing two weakly coupled neuronal networks and enhancing its connectivity by plating new dissociated cells. The direction of connections was formed by the asymmetric design of the chip. Such technology can be used to develop a new type of scaffold to recover the modular structure of the network.
Study of the supramolecularly ordered layered structure of chitosan gel films
Authors: Konduktorova A A , Kurochkina V A , Babicheva T S , Shmakov S L , Shipovskaya A B
Published: December 2021

Structural and morphological features of chitosan gel films with a radially periodic structure, obtained by neutralizing the salt form of the polymer with sodium hydroxide or triethanolamine, were visualized by scanning electron microscopy. The formation of such supramolecularly ordered layered structures was found to obey diffusion kinetics and the regularities of Liesegang periodic precipitation. The revealed dependence of the morphostructure of our chitosan gel films on the neutralizing reagent used is due to differences in the diffusion rate of inorganic and organic substance, as well as some spatio-temporal features of the mass transfer process.
Medical applications of porous silicon
Authors: Loginova E M , Shishkina D A , Zhuravleva M A
Published: December 2021

Materials based on porous silicon are extremely attractive for biomedical applications due to their simple and flexible production, biocompatibility, biodegradability, controlled morphology, and multiple ways of introducing the drug into the body. This paper presents the results of studies of porous structures with a broad spectrum antibiotic ceftriaxone. It has been shown that the characteristics of the porous structure change upon saturation of the pores with the drug. It was shown that solutions of porous silicon + ceftriaxone have a characteristic peak at a wavelength of 1070 nm with increasing sonication time
Influence of the nature of a polysaccharide on the surface-morphological and physicomechanical properties of sol–gel plates
Authors: Malinkina O N , Shipovskaya A B
Published: December 2021

Thin-film sol–gel plates based on chitosan and glucomannan polysaccharides in a wide range of compositions were obtained. The effect of the polysaccharide component on the SEM surface morphology and physicomechanical properties was evaluated. It was found that the introduction of the polysaccharide glucomannan (and/or Aloe Vera juice) into the composition of chitosan sol–gel plates increased the elastoplastic characteristics of the samples and had a significant effect on the surface relief of their solid phase. The obtained structures can be used for the design of bioadhesive sensor coatings with a high therapeutic effect, which is an urgent area for theranostics and regenerative medicine.