bluuebunny/crossref_metadata_2025 huggingface dataset:
Endoscopic submucosal resection: a technique using novel devices for incision and resection of neoplastic lesions
Authors: Metter Klaus , Aepli Patrick , Dumoulin Franz Ludwig , Hayee Bu'Hussain , Grund Karl-Ernst , Farin Günter , Frei Remus
Published: December 2021

Background Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) are established techniques for treatment of superficial gastrointestinal neoplasia. Limitations of EMR are low en bloc resection rates for larger lesions, resulting in frequent recurrences. Major disadvantages of ESD are technical difficulty and long procedure times. We evaluated technical feasibility and safety of newly designed devices for en bloc resection of lesions measuring 20–40 mm in a technique called endoscopic submucosal resection (ESR).

Methods This case series included 93 lesions from different locations (11 stomach, 25 colon, 57 rectum) with a median size of 29 mm (range 10–70). ESR was performed using two novel instruments for circumferential mucosal incision and deep submucosal resection, respectively.

Results Resection by ESR was feasible in all cases. En bloc and R0 rates were insufficient when ESR was attempted without prior circumferential mucosal incision, but were 70 % and 63 %, respectively, when mucosal incision was done before application of the submucosal resection device. We observed three complications (two delayed bleedings, one microperforation) but no cases of emergency surgery or 30-day mortality.

Conclusions Results demonstrated feasibility and excellent safety of ESR using two novel devices for en bloc resection of early gastrointestinal neoplasia. The technique offered relative technical ease and high efficacy.
Respiratory Syncytial Virus
Authors: Nam Hannah H. , Ison Michael G.
Published: December 2021

Human respiratory syncytial virus (RSV) is a negative sense single-stranded RNA virus that can result in epidemics of seasonal respiratory infections. Generally, one of the two genotypes (A and B) predominates in a single season and alternate annually with regional variation. RSV is a known cause of disease and death at both extremes of ages in the pediatric and elderly, as well as immunocompromised populations. The clinical impact of RSV on the hospitalized adults has been recently clarified with the expanded use of multiplex molecular assays. Among adults, RSV can produce a wide range of clinical symptoms due to upper respiratory tract infections potentially leading to severe lower respiratory tract infections, as well as exacerbations of underlying cardiac and lung diseases. While supportive care is the mainstay of therapy, there are currently multiple therapeutic and preventative options under development.
Temporal Trend in SARS-CoV-2 Symptoms in Pregnant Women
Authors: London Viktoriya , Blitz Matthew J. , Solmonovich Rachel , Silver Michael , Minkoff Howard
Published: December 2021

Objective The objective of this study was to examine temporal trends in the clinical presentation of patients diagnosed with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in pregnancy.

Study Design This is a retrospective cohort study of pregnant women who were universally screened for SARS-CoV-2 and tested positive. This multi-center study of admissions to labor and delivery units in New York City and Long Island included all SARS-CoV-2-infected pregnant women admitted to labor and delivery units between April 10th and June 4th 2020. Six Northwell Health hospitals and Maimonides Medical Center were included in the study. The main measures of the study included patient reports of COVID-19 symptoms: fever, cough, chest pain, shortness of breath, nausea, vomiting, and intensive care unit (ICU) admissions. The main outcome measure was the percentage of all infected women who reported any of the above symptoms.

Results In total, 427 infected pregnant women were included in the study. There was a statistically significant decline in the percentage of patients presenting with any symptoms over the course of the study. In addition, disease severity, symptoms of fever, cough, and chest pain/shortness of breath also significantly declined over time, and no ICU admissions were noted after the third week of April.

Conclusion There was a temporal shift away from symptomatic presentation in pregnant women diagnosed with SARS-CoV-2 over the course of the first months of the epidemic in New York. Further studies are necessary to elucidate the cause of this change in presentation among pregnant women, to determine whether this trend is also observed in other patient populations.

Key Points
Evaluation of a Symptom-Based Algorithm for Managing Battery Ingestions in Children
Authors: Fraser James A. , Briggs Kayla B. , Svetanoff Wendy Jo , Attard Thomas M. , Oyetunji Tolulope A. , St Peter Shawn D.
Published: December 2021

Objectives While complications from battery ingestion can be severe, especially with the emergence of stronger battery elements, not all ingestions require prompt removal. We aim to evaluate a symptom-focused algorithm for battery ingestion that emphasizes observation over intervention to investigate its safety.

Materials and Methods Patients were identified through a query of foreign-body ingestion radiographs obtained between 2017 and 2020. A retrospective chart review was then performed of all patients who presented with button battery ingestions to identify compliance with our algorithm, overall outcomes, and complications.

Results In total, 2% of all radiographs (44/2,237) demonstrated button battery ingestions. The median age of patients was 3.8 years (interquartile range, 2.6–5.3). Most batteries were found in the stomach (64%, n = 28), but were also identified in the esophagus (14%, n = 6), small bowel (14%, n = 6), and colon (9%, n = 4). All esophageal batteries were managed with immediate endoscopic retrieval. Ten gastric batteries were not managed per protocol, with seven admitted for observation despite being asymptomatic and repeat abdominal X-rays demonstrating persistent gastric location of the battery. Four patients underwent esophagogastroduodenoscopy; however, in two patients the battery had migrated past the stomach prior to intervention. All small bowel batteries and three of four asymptomatic colon batteries were managed per protocol; one patient had additional imaging that demonstrated battery passage.

Conclusion Adherence to a symptom-focused protocol for conservative management of button battery ingestions beyond the gastroesophageal junction is safe and frequently does not require admission, serial imaging, or intervention.
Constraints to urban agriculture in southeast Nigeria
Authors: Olumba Chukwudi Charles , Olumba Cynthia Nneka , Alimba Jonathan Okechukwu
Published: December 2021

Urban agriculture (UA) is promoted as a viable strategy to support the food demands of the increasing urban population in the global south. However, UA faces severe constraints that could undermine this potential. To sustain urban food production, there is a research need to identify the main factors deterring UA activities. This study, therefore, aims to examine the constraints faced by urban farmers in carrying out their UA production activities. Two hundred and eighty urban farmers selected through a multi-stage sampling technique were used for the study. Data were collected using a questionnaire/interview schedule and analysed using descriptive statistics and principal component analysis (PCA). The study shows that the urban farmers were engaged in four main types of agro-enterprises. They include crop production, livestock production, agro-processing, and the supply of farming inputs. The majority of the UA farmers indicated that they were into maize production (75%), poultry production (60%), and 25% were into fish farming. The PCA result suggests three key constraints to UA, namely infrastructural constraints, socio-economic/environmental constraints, and institutional constraints. For UA in southeast Nigeria to reach its full potential, the study recommends proactive policy responses in support of UA. Also required is infrastructural support in terms of good road networks and marketing facilities to best support UA activities.
Beam halo measurements for special bunches in a storage ring by using a coronagraph
Authors: Hwang Ji-Gwang , Schiwietz Gregor , Goslawski Paul , Ries Markus
Published: December 2021

We demonstrate an experimental methodology for measuring the halo distribution of special bunches in a storage ring using a synchrotron radiation coronagraph composed of the objective lens and a re-diffraction system. The optimum parameters for the coronagraph were investigated within several boundary conditions by applying a paraxial Fourier transformation sequentially from one plane to the next plane. In addition, the effect of Mie-scattering was estimated for different polishing-quality lenses and it shows that a high-quality lens is capable of achieving a dynamic range of the monitor of about 104. The capability of the halo monitor has been demonstrated by measuring the horizontal particle distribution of special bunches in beam experiments at the BESSY II storage ring. This monitor offers a new opportunity for continuous monitoring of special bunches in the storage ring such as transverse resonance island buckets and pulse-picking by resonant excitation, which open new horizons for storage rings that are capable of sophisticated experiments using a single bunch signal as well as serving high-flux users simultaneously.
Suppressing thermal conductivity of nano-grained thermoelectric material using acoustically hard nanoparticles
Authors: Zheng Jianlin , Kodera Yasuhiro , Xu Xia , Shin Sunmi , Chung Ka Man , Imai Takahito , Ihnfeldt Robin V. , Garay Javier E. , Chen Renkun
Published: December 2021

We engineered the thermal conductivity of nano-grained Bi0.5Sb1.5Te3 (BST) by embedding SiO2 and diamond nanoparticles (NPs) with concentration ranging from 0.5 to 5 vol. %. The embedded NPs work as additional scattering centers for long mean free path phonons that are not effectively scattered by the grain boundaries. We found that both the SiO2 and diamond NPs materially reduced the lattice thermal conductivity (κlat) within the temperature range of 50–300 K, with stronger reduction occurring at a lower temperature. Furthermore, the diamond NPs were found to cause large reduction in κlat compared to the SiO2 NPs at the same concentrations. Further theoretical analysis showed that the diamond NPs possess about tenfold higher interfacial thermal resistance with the BST matrix compared to that of SiO2 NPs, due to the larger acoustic mismatch between diamond and BST as compared to SiO2 and BST. As a result of the large reduction of κlat, the thermoelectric figure of merit (ZT) was enhanced by 15% at room temperature with 0.5 vol. % diamond NP relative to the pristine nano-grained samples without the NPs.
Simulation of adiabatic quantum computing for molecular ground states
Authors: Kremenetski Vladimir , Mejuto-Zaera Carlos , Cotton Stephen J. , Tubman Norm M.
Published: December 2021

Quantum computation promises to provide substantial speedups in many practical applications with a particularly exciting one being the simulation of quantum many-body systems. Adiabatic state preparation (ASP) is one way that quantum computers could recreate and simulate the ground state of a physical system. In this paper, we explore a novel approach for classically simulating the time dynamics of ASP with high accuracy and with only modest computational resources via an adaptive sampling configuration interaction scheme for truncating the Hilbert space to only the most important determinants. We verify that this truncation introduces negligible error and use this new approach to simulate ASP for sets of small molecular systems and Hubbard models. Furthermore, we examine two approaches to speeding up ASP when performed on quantum hardware: (i) using the complete active space configuration interaction (CASCI) wave function instead of the Hartree–Fock initial state and (ii) a nonlinear interpolation between the initial and target Hamiltonians. We find that starting with a CASCI wave function with a limited active space yields substantial speedups for many of the systems examined, while nonlinear interpolation does not. In additional, we observe interesting trends in the minimum gap location (based on the initial state) as well as how state preparation time can depend on certain molecular properties, such as the number of valence electrons. Importantly, we find that the required state preparation times do not show an immediate exponential wall that would preclude an efficient run of ASP on actual hardware.
Self-sustaining MoS2 nanomechanical oscillators and feedback cooling
Authors: Lee Jaesung , Feng Philip X.-L.
Published: December 2021

We report on the experimental demonstration of self-sustaining feedback oscillators referenced to ultrathin molybdenum disulfide (MoS2) nanomechanical resonators vibrating in the ∼10 to 20 MHz range. Based on comprehensive open-loop characterization of MoS2 resonators with dynamic ranges up to 85 dB, self-sustaining oscillators are constructed by incorporating the MoS2 resonators into an optoelectronic feedback circuitry. The prototyped MoS2 self-sustaining oscillators generate stable radio frequency waveforms with frequency stability (measured in Allan deviation) down to ∼2 × 10−5 and phase noise mainly limited by electronic thermal noise. Beyond self-sustaining oscillations, we demonstrate feedback cooling of thermomechanical motion of a bilayer (2L) MoS2 resonator from 300 K to 255 K by tuning the phase in the feedback, suppressing or “squashing” the noise level of the system.
Decay of excess carriers in a two-defect model semiconductor: A time-resolved photoluminescence study
Authors: Hariharan Ashwin , Schäfer Sascha , Heise Stephan J.
Published: December 2021

The study of charge carrier decay dynamics in semiconductors plays an important role in determining various device properties, for example, the bulk minority carrier lifetime and the potential drop at interfaces. Time-resolved photoluminescence spectroscopy is an efficient technique to extract carrier decay time constants, with the simplest case being that of a mono-exponential decay controlled by a single type of recombination center. However, many modern materials often display multi-exponential decay behavior influenced by a broad distribution of defects. Utilizing CuIn1-xGaxSe2 as a reference system, we present a comprehensive and systematic theoretical study of the decay kinetics in a non-interacting two-defect-level system by using both the classical analytical approach developed by Hornbeck and Haynes and a homogeneous kinetic rate equation model solved numerically. We show how the trapping level's carrier capture cross-section symmetry factor and the initial injection level controls the parameter range for the agreement between these two approaches, analyzing the validity of multi-exponential fits for extracting the carrier lifetime. Further, we analytically and numerically demonstrate that information on the carrier recombination lifetime is contained in the fast time constant, whereas the agreement of the subsequent slow time constant with the analytical model depends on the energetic position of the defect level within the bandgap.
Reservoir computing with random and optimized time-shifts
Authors: Del Frate Enrico , Shirin Afroza , Sorrentino Francesco
Published: December 2021

We investigate the effects of application of random time-shifts to the readouts of a reservoir computer in terms of both accuracy (training error) and performance (testing error). For different choices of the reservoir parameters and different “tasks,” we observe a substantial improvement in both accuracy and performance. We then develop a simple but effective technique to optimize the choice of the time-shifts, which we successfully test in numerical experiments.
Microwave generation modes of ferrite nonlinear transmission lines up to 20 GHz
Authors: Ulmaskulov M. R. , Shunailov S. A.
Published: December 2021

The generation modes of high-voltage microwave oscillations of nonlinear coaxial transmission lines filled with NiZn ferrite rings with an ordinary (smoothed) hysteresis loop and MgMn ferrite rings with a rectangular hysteresis loop are presented for comparison. Results across a wide frequency range (∼5.5–12.7 GHz) demonstrated that the anisotropic magnetic properties of ferrite with a rectangular loop provide a much more stable and effective generation of powerful microwave oscillations with peak amplitudes up to −350 kV and deep modulation in a wide biasing field (∼4–85 kA/m), as well as the possibility of a generation mode without an external biasing field. New experimental data enable the observed processes in nonlinear ferrite lines to be related to the theoretical positions of the ferrite anisotropic properties and the spin waves of magnetization precession under high-power microwave radiation. Results were also considered in relation to the theory of ferrite. The possibility of achieving an effective frequency of oscillations of 18.5 (up to 20) GHz using solid-state nonlinear transmission lines was also shown.
A DFT+U look into experimentally synthesized monoclinic scheelite BiVO4
Authors: Fardush Tanha Jannatul , Farhad S. F. U. , Honey U. , Tanvir N. I. , Hasan Tarique , Shahriyar Nishat Sadiq , Kabir Alamgir , Ahmed Shahran , Hakim Mahmuda , Khan M. N. I. , Moniruzzaman Mohammad , Ahmed Imtiaz
Published: December 2021

We present a combined experimental and Hubbard interaction corrected density functional theory (DFT+U) based study of monoclinic scheelite (ms) bismuth vanadate BiVO4 (BVO). The ms-BVO samples were synthesized using the standard solid state reaction technique. The ms phase of the synthesized BVO samples has been confirmed from Rietveld analysis of the powder x-ray diffraction pattern and room temperature Raman spectroscopy. Both experimentally obtained crystal parameters and Raman peak positions were benchmarked against the DFT+U simulations. The variations in morphology and chemical concentrations due to different sintering temperatures and milling times were analyzed using field emission scanning electron microscopy and energy dispersive x-ray spectroscopy. The measured energy bandgap in the range of 2.38–2.58 eV from UV-Vis-NIR diffuse reflection spectroscopy was explained within the context of grain size variations in combination with bismuth and oxygen vacancies from DFT+U simulations.
Diffuse Fluorescence Tomography
Authors: Faulkner Denzel , Ochoa Marien , Nizam Navid Ibtehaj , Gao Shan , Intes Xavier
Published: December 2021

This chapter discusses the field of diffuse fluorescence tomography in terms of fluorescence diffuse optical tomography (FDOT) and fluorescence molecular tomography (FMT). A brief overview of the forward photon propagation model is given. In addition, the techniques and challenges associated with solving the inverse problem, required for successful reconstruction, are discussed. Moreover, special attention is given to the different instrumentation used in diffuse fluorescence tomography. This includes the instrumentation associated with adequate illumination of the sample as well as efficient detection. Furthermore, the diverse applications of diffuse fluorescence tomography are explored, ranging from its use in biomarkers to preclinical applications and translational imaging. Finally, the chapter looks at the emerging technologies, which will shape the field in the near future.
High-entropy alloys: properties and prospects of application as protective coatings
Authors: Gelchinski B. R. , Balyakin I. A. , Yuryev A. A. , Rempel A. A.
Published: December 2021

Alloys with high configurational entropy fundamentally differ from traditional alloys as they contain not one, but five or more basic elements with concentrations of 5 to 35 at.% each. Owing to the unique elemental composition, high-entropy alloys can have unusual functional properties such as high strength and wear resistance, exceptional heat resistance, good structural stability and good resistance to corrosion and oxidation. The review considers methods of synthesis of high-entropy alloys, methods and results of computer simulation of the high-entropy alloy structures and applications of such alloys as corrosion-, heat- and radiation-resistant materials and biomedical materials. Particular attention is paid to the prospects for the use of such alloys as protective coatings.
 The bibliography includes 352 references.
Transcriptional network orchestrating regional patterning of cortical progenitors
Authors: Ypsilanti Athéna R. , Pattabiraman Kartik , Catta-Preta Rinaldo , Golonzhka Olga , Lindtner Susan , Tang Ke , Jones Ian R. , Abnousi Armen , Juric Ivan , Hu Ming , Shen Yin , Dickel Diane E. , Visel Axel , Pennacchio Len A. , Hawrylycz Michael , Thompson Carol L. , Zeng Hongkui , Barozzi Iros , Nord Alex S. , Rubenstein John L.
Published: December 2021

Significance

Development of cortical areas begins in cortical stem cells through the action of morphogens controlling the graded expression of transcription factors (TFs). Here, we have systematically identified the TFs and gene regulatory elements (REs) that together control regional pattering of the cortical progenitor zone; these data have led us to propose a cortical regionalization TF network. To identify REs active in this network, we performed TF chromatin immunoprecipitation followed by sequencing (ChIP-seq) and chromatin-looping conformation experiments as well as assays for epigenomic marks and DNA accessibility in purified ventricular zone (VZ) progenitor cells in wild-type and patterning mutant mice. This integrated approach has laid the foundations to identify a TF network and cortical VZ REs involved in cortical regional patterning.
Genetic studies of human–chimpanzee divergence using stem cell fusions
Authors: Song Janet H. T. , Grant Rachel L. , Behrens Veronica C. , Kučka Marek , Roberts Kingman Garrett A. , Soltys Volker , Chan Yingguang Frank , Kingsley David M.
Published: December 2021

Significance

Comparative studies of humans and chimpanzees have revealed many anatomical, physiological, behavioral, and molecular differences. However, it has been challenging to map these differences to particular chromosome regions. Here, we develop a genetic approach in fused stem cell lines that makes it possible to map human–chimpanzee molecular and cellular differences to specific regions of the genome. We illustrate this approach by mapping chromosome regions responsible for species-specific gene expression differences in fused tetraploid cells. This approach is general, and could be used in the future to map the genomic changes that control many other human–chimpanzee differences in various cell types or organoids in vitro.
Efficient progranulin exit from the ER requires its interaction with prosaposin, a Surf4 cargo
Authors: Devireddy Swathi , Ferguson Shawn M.
Published: December 2021

Progranulin is a lysosomal protein whose haploinsufficiency causes frontotemporal dementia, while homozygous loss of progranulin causes neuronal ceroid lipofuscinosis, a lysosomal storage disease. The sensitivity of cells to progranulin deficiency raises important questions about how cells coordinate intracellular trafficking of progranulin to ensure its efficient delivery to lysosomes. In this study, we discover that progranulin interactions with prosaposin, another lysosomal protein, first occur within the lumen of the endoplasmic reticulum (ER) and are required for the efficient ER exit of progranulin. Mechanistically, we identify an interaction between prosaposin and Surf4, a receptor that promotes loading of lumenal cargos into COPII-coated vesicles, and establish that Surf4 is critical for the efficient export of progranulin and prosaposin from the ER. Collectively, this work demonstrates that a network of interactions occurring early in the secretory pathway promote the ER exit and subsequent lysosomal delivery of newly translated progranulin and prosaposin.
Bhlhe40 function in activated B and TFH cells restrains the GC reaction and prevents lymphomagenesis
Authors: Rauschmeier René , Reinhardt Annika , Gustafsson Charlotte , Glaros Vassilis , Artemov Artem V. , Dunst Josefine , Taneja Reshma , Adameyko Igor , Månsson Robert , Busslinger Meinrad , Kreslavsky Taras
Published: December 2021

The generation of high-affinity antibodies against pathogens and vaccines requires the germinal center (GC) reaction, which relies on a complex interplay between specialized effector B and CD4 T lymphocytes, the GC B cells and T follicular helper (TFH) cells. Intriguingly, several positive key regulators of the GC reaction are common for both cell types. Here, we report that the transcription factor Bhlhe40 is a crucial cell-intrinsic negative regulator affecting both the B and T cell sides of the GC reaction. In activated CD4 T cells, Bhlhe40 was required to restrain proliferation, thus limiting the number of TFH cells. In B cells, Bhlhe40 executed its function in the first days after immunization by selectively restricting the generation of the earliest GC B cells but not of early memory B cells or plasmablasts. Bhlhe40-deficient mice with progressing age succumbed to a B cell lymphoma characterized by the accumulation of monoclonal GC B-like cells and polyclonal TFH cells in various tissues.
An analysis of stochastic variance reduced gradient for linear inverse problems
*
Authors: Jin Bangti , Zhou Zehui , Zou Jun
Published: December 2021

Stochastic variance reduced gradient (SVRG) is a popular variance reduction technique for accelerating stochastic gradient descent (SGD). We provide a first analysis of the method for solving a class of linear inverse problems in the lens of the classical regularization theory. We prove that for a suitable constant step size schedule, the method can achieve an optimal convergence rate in terms of the noise level (under suitable regularity condition) and the variance of the SVRG iterate error is smaller than that by SGD. These theoretical findings are corroborated by a set of numerical experiments.
Two-dimensional ultrathin MoS2 modified hydrogenated TiO2 nanoparticles for superior photocatalytic degradation under simulated sunlight
Authors: Wang Dandan , Yu Bo , Li Hongji , Liu Qianyu , Sun Dongshu , Wang Jia , Che Guangbo , Liu Chunbo
Published: December 2021

Photocatalysis is an effective technology for degradation of organic contaminants. Herein, we firstly synthesized hydrogenated TiO2 (HT) nanoparticles by calcining P25, and on the basis of HT, two-dimensional ultrathin MoS2/HT binary composites with different component ratios (MHT-20%, MHT-30% and MHT-35%) were controlled prepared. UV–vis diffuse reflectance spectra (DRS) showed that the HT nanoparticles exhibited stronger absorption towards visible light in the range of 550–800 nm compared to P25, and the introduction of two-dimensional ultrathin MoS2 nanosheets further enhanced the visible light absorption ability of MHT composites. Under simulated sunlight irradiation, the removal test of methylene blue (MB) in the present of various photocatalysts indicated that the catalytic performance of HT sample was better than that of P25, and MHT binary composites displayed more excellent photocatalytic performance. A maximum removal efficiency of MB reached 95% within 4 h over MHT-30% photocatalyst. Moreover, the kinetic constant of MHT-30% catalyst is 5.6, 3.6 and 2.5 times as much as that of P25, MoS2 and HT, respectively. In addition, the repeated degradation study and composition analysis of MHT-30% before and after photocatalytic reaction showed that MHT-30% photocatalyst exhibited good stability, and the removal rate of MB still reached 88% in four cycles. The improved and stable photocatalytic performance of MHT-30% can be attributed to band matching and tight interface bonding between MoS2 and HT, which accelerated the electron transfer and broaden the visible-light response range.
Shock-induced plasticity and phase transformation in single crystal magnesium: an interatomic potential and non-equilibrium molecular dynamics simulations
Authors: Jian Zhiyong , Chen Yangchun , Xiao Shifang , Wang Liang , Li Xiaofan , Wang Kun , Deng Huiqiu , Hu Wangyu
Published: December 2021

An effective and reliable Finnis–Sinclair (FS) type potential is developed for large-scale molecular dynamics (MD) simulations of plasticity and phase transition of magnesium (Mg) single crystals under high-pressure shock loading. The shock-wave profiles exhibit a split elastic–inelastic wave in the [0001]HCP shock orientation and a three-wave structure in the [10-10]HCP and [-12-10]HCP directions, namely, an elastic precursor, a followed plastic front, and a phase-transition front. The shock Hugoniot of the particle velocity (U
p) vs the shock velocity (U
s) of Mg single crystals in three shock directions under low shock strength reveals apparent anisotropy, which vanishes with increasing shock strength. For the [0001]HCP shock direction, the amorphization caused by strong atomic strain plays an important role in the phase transition and allows for the phase transition from an isotropic stressed state to the product phase. The reorientation in the shock directions [10-10]HCP and [-12-10]HCP, as the primary plasticity deformation, leads to the compressed hexagonal close-packed (HCP) phase and reduces the phase-transition threshold pressure. The phase-transition pathway in the shock direction [0001]HCP includes a preferential contraction strain along the [0001]HCP direction, a tension along [-12-10]HCP direction, an effective contraction and shear along the [10-10]HCP direction. For the [10-10]HCP and [-12-10]HCP shock directions, the phase-transition pathway consists of two steps: a reorientation and the subsequent transition from the reorientation hexagonal close-packed phase (RHCP) to the body-centered cubic (BCC). The orientation relationships between HCP and BCC are (0001)HCP ⟨-12-10⟩HCP // {110}BCC ⟨001⟩BCC. Due to different slipping directions during the phase transition, three variants of the product phase are observed in the shocked samples, accompanied by three kinds of typical coherent twin-grain boundaries between the variants. The results indicate that the highly concentrated shear stress leads to the crystal lattice instability in the elastic precursor, and the plasticity or the phase transition relaxed the shear stress.
Analysis and improvement of the Bancroft algorithm for GNSS satellite orbit determination
Authors: Chen Yongchang , Sheng Chuanzhen , Yi Qingwu , Li Ran , Ma Guangqing , Zhang Jingkui
Published: December 2021

Satellite orbit information is crucial for ensuring that global navigation satellite systems (GNSSs) provide appropriate positioning, navigation and timing services. Typically, users can obtain access to orbit information of a specific accuracy level from navigation messages or precise ephemeris products. Without this information, a system will not be able to provide normal service. In response to this problem, initial orbit information of a certain level of precision must be obtained to support subsequent applications, such as broadcasting or precise ephemeris calculations, thereby ensuring the successful subsequent operation of the navigation system. One of two ways to calculate the initial orbit of a GNSS satellite is to utilize ground tracking stations to observe satellite vector information in the geocentric inertial system; the second way is to utilize GNSS range observations and known orbit information from other satellites. For the second approach, some researchers use the Bancroft algorithm combined with receiver clock offset to determine the initial orbit of GNSS satellites. Because this method requires an additional known receiver clock offset, we study the dependence of the Bancroft algorithm on clock offset in GNSS orbit determination. By assessing the impact of errors of different magnitude on the accuracy of the orbit results, we obtain experimental conclusions. After comprehensively analyzing various errors, we determine the accuracy level that the Bancroft algorithm can achieve for orbit determination without considering receiver clock correction. Dual-frequency and single-frequency pseudorange data from International GNSS Service stations are used in orbit determination experiments. When a small receiver clock offset is considered and no correction is made, the deviations in the calculated satellite positions in three dimensions are approximately 979.3 and 1118.1 m (dual and single frequency); with a satellite clock offset, these values are approximately 928.8 and 1062.7 m (dual and single frequency).
A 1D CNN for high accuracy classification and transfer learning in motor imagery EEG-based brain-computer interface
Authors: Mattioli F , Porcaro C , Baldassarre G
Published: December 2021

Objective. Brain-computer interface (BCI) aims to establish communication paths between the brain processes and external devices. Different methods have been used to extract human intentions from electroencephalography (EEG) recordings. Those based on motor imagery (MI) seem to have a great potential for future applications. These approaches rely on the extraction of EEG distinctive patterns during imagined movements. Techniques able to extract patterns from raw signals represent an important target for BCI as they do not need labor-intensive data pre-processing. Approach. We propose a new approach based on a 10-layer one-dimensional convolution neural network (1D-CNN) to classify five brain states (four MI classes plus a ‘baseline’ class) using a data augmentation algorithm and a limited number of EEG channels. In addition, we present a transfer learning method used to extract critical features from the EEG group dataset and then to customize the model to the single individual by training its late layers with only 12-min individual-related data. Main results. The model tested with the ‘EEG Motor Movement/Imagery Dataset’ outperforms the current state-of-the-art models by achieving a

99.38
%

accuracy at the group level. In addition, the transfer learning approach we present achieves an average accuracy of

99.46
%

. Significance. The proposed methods could foster the development of future BCI applications relying on few-channel portable recording devices and individual-based training.
Method for dynamic measurement of thermal diffusivity during laser soldering of biological tissues
Authors: Ryabkin D I , Molodykh V V , Gerasimenko A Yu.
Published: December 2021

In this paper, we propose a method for dynamic measurement of the thermal diffusivity coefficient during laser soldering of biological tissues. The method is based on modelling the function of temperature dependence on time during cooling of biological tissue after exposure to laser radiation. The simulation is carried out by solving the heat equation for a homogeneous biological tissue and the absence of external heat sources. The desired value of the thermal diffusivity coefficient was determined by optimizing the residual functional of the temperature functions from time obtained experimentally and by solving the thermal diffusivity equation. Experiments were carried out to measure the thermal diffusivity coefficient by the proposed method for myocardial and skin tissues at maximum heating temperatures of 40, 50, 60 °C. The measured values of the thermal diffusivity coefficient for the myocardium are in the range from 2.3 to 2.7 m2/s*10-6, and for the skin from 1.5 to 1.7 m2/s*10-6.
Application of machine learning methods for automated classification and routing in ITIL
Authors: Nikulin VV , Shibaikin S D , Vishnyakov A N
Published: December 2021

The article analyzes the application of machine learning methods for automated classification and routing in ITIL library. ITSM technology and ITIL are considered. The definitions of the incident and IT services are given. Then, the vectorization and extraction of keywords in the information written in natural language is carried out and lemmatization and TF-IDF measure will be used. A comparative analysis of the application of machine learning methods is given as well as a comparison of the results of automatic classification of text information using gradient boosting and a convolutional neural network. Various parameters of these methods are considered and the most effective method of machine learning is determined. The results of using machine learning methods for automated classification of incidents allows high-precision routing of requests for restoring the operability of IT services, reducing response time and errors associated with the human factor.
Measuring the depth of surface cracks using alternating current potential drop technique, with suppression of the influence of the electromagnetic properties of the metal
Authors: Shkatov P N
Published: December 2021

Traditional measuring techniques often lead to errors due to the need to register signals in both defective and defect-free areas. In this paper, we introduce an alternating current potential drop technique with detuning from the influence of variations in the electromagnetic properties of the metal achieved by registering a signal only at the defective site. We show that, with an appropriate choice of measurement parameters, the use of the proposed technique leads to an increase in sensitivity to the crack depth as well as to an increase in the measurement range.
Building a decision support system based on fuzzy logic to reduce the total harmful emissions from a fossil fuel boiler or power plant
Authors: Filinkov L I , Likhter A M , Rybakov A V , Varlamov K S
Published: December 2021

This article discusses the software implementation using the theory of fuzzy sets. To build the model, we use data on wind direction, wind strength, the distance of residential buildings and the population of the expected area of pollution distribution. To do this, the most critical parameters must be ranked such as size of population. wind speed and wind direction. We will consider them as input data. We use Scilab as the processing environment.
Control system of intelligent buildings based on convolutional neural networks
Authors: Lezhnina Yu. A. , Maltseva N. S.
Published: December 2021

In recent years, with the development of ”Internet of things” appeared another concept – smart home environment, which is defined as the physical infrastructure to operate of ambient intelligence. For the effective operation of such facilities requires to develop of new methods and approaches for adaptive control. In this paper, we analyzed the parameters characterizing the state of the control object, identify the necessary set of measured parameters obtained from the sensors, and an informative set of input parameters. We design method of training of neural network.
Dynamics of media with stationary parameters and telegraph equations
Authors: Kushner A G , Kushner E N
Published: December 2021

The paper proposes an approach for constructing exact solutions of differential equations of mathematical physics, in particular, the telegraph equation. The method is based on the theory of finite-dimensional dynamics of systems of evolutionary differential equations. This theory is a natural extension of the theory of dynamical systems to partial differential equations. It allows one to construct exact solutions of partial differential equations even in the case when equations do not have symmetry algebras sufficient for integration.
Diffraction propagation of vortex diffractals
Authors: Korolenko P , Kubanov R , Pavlov N , Zotov A
Published: December 2021

A brief retrospective analysis of studies of fractal light radiation is carried out. To assess the prospects of this scientific direction, new original results of studying the diffraction propagation of vortex wave beams with a fractal structure (vortex diffractals) are also presented. For this purpose, computational algorithms and related software have been developed. In calculating the amplitude-phase and scaling characteristics of diffractals two-dimensional Weierstrass functions and multistructures of Gaussian beams were used. The results indicate a high information capacity of vortex diffractals and explain their resistance to the influence of turbulence in the propagation medium.
Active positioning system based on hall-effect sensors
Authors: Karlova G F , Avdochenko B I , Belozyorova E A
Published: December 2021

The paper investigates the behavior of Hall-effect sensors (HES) operating in microwave frequency range. In order to evaluate the capabilities of small radars based on HES’s, the calculation of HES output voltage dependence on microwave intensity is carried out. It is shown that at power flow density I(t) = 10 μW/cm2 (a permissible value for a long-term human body exposure) the single GaAs sensor output Hall voltage U
H ~ 0.03 μV.

It is also demonstrated that integration of signals with due regard for their delays (as in the case of range-difference radar systems) gives an opportunity to obtain electromagnetic image of any point within the antenna coverage area with centimeter-level accuracy. The paper describes the experimental assembly and estimates the distances to the detected contrasting objects.
Investigation of the effect of the summation of monopolar pulses of individual generators for a bipolar UWB pulse formation
Authors: Balzovsky E V , Lysykh P M
Published: December 2021

A technique for the formation of ultra-wideband bipolar pulses using two synchronized generators of monopolar pulses of different polarities and a broadband ring summing unit is considered. In contrast to the traditional circuit on short-circuited segments of line, the proposed approach allows varying the duration of bipolar pulses by changing the time delay between the generators
Enhancing performance in a LOS MIMO communication using a passive repeater
Authors: Eissa Mahmoud , Sukhanov D
Published: December 2021

This paper presents a technique for obtaining a well-conditioned channel matrix in a line of sight multiple input multiple output (MIMO) environment. The technique is based on the implementation of a back-to-back antenna system as a passive repeater to enhance performance in MIMO systems. The flexible configuration with no need for a phase controller allows to spread the proposed repeater in MIMO communications to ensure spatial multiplexing and enhance capacity. A condition number and matrix rank are proposed as metrics to demonstrate the validity of the proposed method.
Two-dimensional THz reflectometry of a periodic structure obtained by additive technology
Authors: Badin A V , Berdyugin A I , Moskalenko V D , Simonova K V , Gursky R P
Published: December 2021

This paper considers the development and application of a system of reflectometry for the analysis of the homogeneity of structures manufactured by additive technologies. A system of reflectometry based on a backward wave oscillator, a two-dimensional object positioning system and an optoacoustic detector (Goley cell) is described. The results of reflectometry of the hexagonal periodic structure of cells based on acrylonitrile butadiene styrene at a wavelength of 343 microns are presented.
Modeling of electrotransport properties of Li-intercalated graphene film
Authors: Sergeyev D , Duisenova A , Embergenov Zh
Published: December 2021

In this work, within the framework of density functional theory combined with the method of nonequilibrium Green’s functions the density of states, transmission spectrum, current-voltage characteristics, and differential conductivity of Li-intercalated graphene (LiC6) have been determined. It is shown that in the energy range of -1.3÷-1.05 eV the quasiparticle transport through the nanostructure is disable. The features of IV- and dI/dV-characteristics of LiC6 in the form of decreasing of resistance in the range of -0.4÷0.4 V were revealed, and in the interval of 0.4÷1.4 V formation of negative differential resistance area, related to scattering of quasiparticles. It is established, that LiC6 nanodevice has 12÷13 ballistic channels and has the maximum amount of conductance 12÷13G0
, where Go
is the conductance quantum.
Issues of technical implementation of ground-based microwave radiometric system calibration
Authors: Rostokin I N , Fedoseeva E V , Rostokina E A , Shchukin G G
Published: December 2021

The theoretical bases of a method of carrying out calibration of microwave radiometric system on a noise signal of the external noise generator are analysed, the parameters setting value of gain of antenna temperature at introduction in structure of system of such external source of a calibration signal are determined. The questions of technical realization of an external source of a calibration signal for microwave radiometric system are considered, the structural scheme is presented, the place of its arrangement in structure of the antenna is determined. The necessity of using a horn antenna to create directional radiation towards the mirror antenna emitter is shown. The data on the design of such a calibration signal source for the case of its use in a three-band microwave radiometric system with the reception of a noise signal at the common antenna aperture and a sequential separation of the input signals of the three bands in the feeder path of the common mirror irradiator are presented. The influence of the design and, accordingly, the directional properties of the horn antenna of a microwave radiometric system calibration signal source on the coefficient characterizing the radiation divergence created by the noise generator horn, as well as the frequency properties of this coefficient are analysed. The results of measurements of radio-thermal radiation by a three-band microwave radiometric system when two calibration periods with reception of a radio-noise signal from an external calibration signal source located at the base of the antenna mirror are presented.
Active IR location as the roadway profilometry method
Authors: Khmelev V L , Fominykh A F
Published: December 2021

This article observe a using of active infrared beam location as roadway surface quality control. Changes in the spatial structure of the emitted IR radiation by surfaces within the capture scene allow creating a depth map of this scene. An optical camera makes it possible to use classical computer vision methods for stitching a depth map. For testing the possibility of using this approach, we made statistical studies on a multiple sample of distance measurements. Here we explain two experimental schemes with a programmable mechanical scanning system. The first one, we had determined the distance, which the image is capture accurately. The second, we measure the planar resolution, a minimum size of the defect that recognize by the infrared beam location system.