bluuebunny/crossref_metadata_2025 huggingface dataset:
Knowledge levels on applications of radiation in medicine among medical practitioners in Ghana
Authors: Hasford F. , Sackey T.A. , Inkoom S. , Sosu E.K. , Hammond E.N.B. , Awua A.K. , Pokoo-Aikins M. , Dery T.B. , Teye S. , Issahaku S. , Eduful E.K. , Boadu M.
Published: April 2021

The evaluation of medical practitioners’ knowledge levels of radiation and safety is essential for planning diagnostic procedures and treatment in radiation medicine. This study sought to identify levels of knowledge and the predictor variables influencing knowledge of medical practitioners on applications of radiation in medicine in Ghana. Online survey was conducted with Google Form consisting of 37-point questionnaire highlighting on physicians’ background information, professional experience, knowledge on radiation usage in medicine, radiation protection and safety. Evaluation of the data was performed by descriptive analysis using frequency distributions and percentages. Among 152 respondents who participated in the study, specialists and consultants made up a higher representation of 46.7%. Two-thirds (64.0%) of the respondents who had received refresher training in the application of radiation in medicine exhibited full knowledge in the field. Medical practitioners who had practiced between 21–25 years were also found to demonstrate full knowledge of the application of radiation in medicine, while 36.6% of those who had practiced for < 6 years demonstrated extensive knowledge. Majority of the medical practitioners, constituting 39.5%, exhibited full knowledge in medical radiation protection and safety. This level of knowledge was found higher than what was demonstrated for general and occupational radiation protection. With medical imaging forming a key component in the diagnosis of several medical conditions, education in the field of radiation usage and radiological protection and safety should be a subject of periodic training for medical practitioners regardless of their level of training or duration of practice
Reference Ranges for Vermis Biometry on Prenatal Ultrasound: Systematic Review and Meta-Analysis
Authors: Rosenbloom Joshua I , Yaeger Lauren H. , Porat Shay
Published: April 2021

Purpose To conduct a systematic review and meta-analysis of published nomograms for fetal vermis biometry.

Materials and Methods A structured literature search was conducted to identify studies that reported normal measurements of the fetal vermis. A customized quality assessment tool was used to review the selected articles. Random effects meta-analysis was used to calculate normal ranges for vermian craniocaudal diameter, anteroposterior diameter, and surface area.

Results A total of 21 studies were included for qualitative review and 3 studies were included for quantitative synthesis. The 3 included articles comprised a total of 10 910 measurements from gestational ages 17–35 weeks. The quality assessment demonstrated that there was generally poor reporting regarding maternal characteristics and neonatal outcomes. Except for one article with a large sample size, the mean number of fetuses per week of gestational age was 15.9, with the lowest number being 5. There was significant statistical heterogeneity. Non-visualization rates ranged from 0–35.4 %. The craniocaudal diameter (reported in 3 articles) increased from a mean of 7.90 mm (95 % confidence interval [CI] 7.42, 8.38) at 17 weeks to 21.90 mm (95 % CI 20.63, 23.16) at 35 weeks gestation. The anteroposterior diameter (reported in 2 articles) increased from 6.30 mm (95 % CI 5.42, 7.18) at 17 weeks to 15.85 (95 %CI 15.49, 16.21) at 32 weeks.

Conclusion Reference ranges for vermis biometry across gestation based on meta-analysis of existing references are provided. However, because many of the underlying studies suffered from significant methodological issues, the ranges should be used with caution.
Case Report of a Benign Looking Malignant ECG–Value of Subtle Signs
Authors: Sharnagat Khushal Lokchand , Kodati Deepthi
Published: April 2021

ECG is one of the primary and most informative bedside tools for the cardiologist, even in the present era. Careful analysis of ECG changes (sometimes subtle) can be life-saving, such as in the case we are presenting now. A 42-year-old gentleman with no obvious coronary risk factors presented with vague pain and subtle ECG changes (outside physician passed off as usual). He was asked to consult a cardiologist. While awaiting outpatient consultation, he collapsed. The patient was resuscitated and coronary angiogram was immediately done, which showed distal left main disease. Successful intervention was carried out with the help of provisional stent strategy, and the patient was discharged safely.
Mixed Reality: Ich sehe was, was du nicht siehst
Authors: Kucera Martin
Published: April 2021

In dreidimensionalen Aufnahmen lassen sich Organstrukturen und räumliche Zusammenhänge besser erkennen. Die neuen Mixed-Reality-Brillen projizieren sie als 3D-Objekte in die reale Welt, deren Träger können sogar gemeinsam mit ihnen interagieren. Das verschafft klinischen Anwendern enorme Vorteile.
Roads to Change: Livelihoods, Land Disputes, and Anticipation of Future Developments in Rural Kenya
Authors: Greiner Clemens , Greven David , Klagge Britta
Published: April 2021

This article examines how rural roads relate to differences in livelihood patterns, attitudes toward social change, and land disputes in Baringo, Kenya. Although their direct use is limited for many residents, roads have a highly differentiating impact. While some households orientate themselves toward roads, those relying more on (agro-)pastoralist livelihoods avoid their proximity. Our findings suggest that better-off households are not the only ones that tend to live closer to roads, but that poorer households do as well. Rather than by socio-economic status, households living closer to roads can be characterized by higher degrees of formal education and also appear to be more open to economic and social change. Our data also highlight dynamics of land disputes in the face of ongoing large-scale infrastructural investments in Kenya’s previously marginal northern drylands.
On the fast waves in a cylindrical current-carrying plasma
Authors: Grishanov N. I. , Azarenkov N. A.
Published: April 2021

The influence of a stationary Ohmic current on the radial structure of fast waves in a cylindrical current-carrying plasma is discussed. To evaluate the dispersion equation for fast waves, they used the dielectric tensor taking into account the radial current structure and geometry of a confining helical magnetic field by the plasma safety factor. It is shown that the dispersion characteristics of fast waves in a current-carrying plasma differ from those for an equilibrium plasma column in a homogeneous magnetic field nearby the cutoffs and resonances due to the rotational transformation (including shear-effects) of the helical magnetic field lines.
Versatile Seebeck and electrical resistivity measurement setup for thin films
Authors: Ferreira-Teixeira Sofia , Carpinteiro Francisco , Araújo João P. , Sousa João B. , Pereira André M.
Published: April 2021

A custom setup for Seebeck coefficient and electrical resistivity measurements of thin films as a function of temperature in the range of 10–300 K was developed. The Seebeck coefficient is measured using a two-probe arrangement and using either a dynamical or steady/quasi-steady differential method. The temperature differences (ΔTs) for these measurements across the samples are achieved by using resistive heaters embedded in two copper blocks. The sample is screwed to these blocks and is in pressured contact with the measurement probes. The electrical resistivity is measured with a two-probe arrangement. To verify the reliability of the developed setup, measurement tests were performed on commercial niobium foil and a specular spin valve previously studied, having obtained a great accordance (within ∼3%) between this setup’s experimental results and the reference measurements.
Molecular simulation study of 3,4-dihydroxyphenylalanine in the context of underwater adhesive design
Authors: Chen Amelia B. , Shao Qing , Hall Carol K.
Published: April 2021

Adhesives that can stick to multiple surface types in underwater and high moisture conditions are critical for various applications such as marine coatings, sealants, and medical devices. The analysis of natural underwater adhesives shows that L-3,4-dihydroxyphenylalanine (DOPA) and functional amyloid nanostructures are key components that contribute to the adhesive powers of these natural glues. The combination of DOPA and amyloid-forming peptides into DOPA-amyloid(-forming peptide) conjugates provides a new approach to design generic underwater adhesives. However, it remains unclear how the DOPA monomers may interact with amyloid-forming peptides and how these interactions may influence the adhesive ability of the conjugates. In this paper, we investigate the behavior of DOPA monomers, (glycine-DOPA)3 chains, and a KLVFFAE and DOPA-glycine chain conjugate in aqueous environments using molecular simulations. The DOPA monomers do not aggregate significantly at concentrations lower than 1.0M. Simulations of (glycine-DOPA)3 chains in water were done to examine the intra-molecular interactions of the chain, wherein we found that there were unlikely to be interactions detrimental to the adhesion process. After combining the alternating DOPA-glycine chain with the amyloid-forming peptide KLVFFAE into a single chain conjugate, we then simulated the conjugate in water and saw the possibility of both intra-chain folding and no chain folding in the conjugate.
The physical properties of the Hall current
Authors: Faisant F. , Creff M. , Wegrowe J.-E.
Published: April 2021

We study the stationary state of Hall devices composed of a load circuit connected to the lateral edges of a Hall bar. We follow the approach developed in a previous work [Creff et al., J. Appl. Phys. 128, 054501 (2020)] in which the stationary state of an ideal Hall bar is defined by the minimum power dissipation principle. The presence of both the lateral circuit and the magnetic field induces the injection of a current: the so-called Hall current. Analytical expressions for the longitudinal and transverse currents are derived. It is shown that the efficiency of the power injection into the lateral circuit is quadratic in the Hall angle and obeys to the maximum transfer theorem. For usual values of the Hall angle, the main contribution of this power injection provides from the longitudinal current flowing along the edges instead of the transverse current crossing the Hall bar.
Broadband acoustic vortex beam generator based on coupled resonances
Authors: Liu Chen , Long Houyou , Ma Chengrong , Jia Yurou , Shao Chen , Cheng Ying , Liu Xiaojun
Published: April 2021

A high-performance acoustic vortex beam generator (VBG) based on artificial micro-structured metamaterials is of great significance in acoustic communication. However, to date, the research on metamaterial VBGs mainly focused on their single frequency properties in the narrow band. Here, we propose a design strategy of broadband VBGs constructed by gradient coupled-resonant meta-atoms, all of which show near-unity transmission amplitudes, while covering 2π phase shifts linearly varied along with frequency throughout the desired overlapping frequency range. Moreover, the phase differences between adjacent meta-atoms are constant at regular intervals within this entire frequency range, allowing the unique wideband response of the proposed VBG. We demonstrate, both in simulations and in experiments, the efficient mode conversion from plane sound wavefronts into vortex beams with a topological charge of 1. Our study provides a platform to manipulate broadband wavefront conversion based on acoustic coupled-resonant metamaterial, which allows us to envision promising acoustic devices with versatile applications.
Antibacterial effects of combined non-thermal plasma and photocatalytic treatment of culture media in the laminar flow mode
Authors: Galaly A. R. , Ahmed O. B. , Asghar Atif H.
Published: April 2021

Acceleration of antibacterial properties is the targeted fashion of the recent part of our project by studying different techniques, on the culture media of E. coli., including the non-thermal effect using atmospheric pressure plasma jet (APPJ) and the non-thermal effects combined with the photocatalytic effects using APPJ coupled with a titanium dioxide TiO2 precursor. The electrical, non-thermal, and optical characteristics of the laminar and turbulent mode flow of a dry argon discharge afterglow using APPJ were vital in the study of the antibacterial properties, with the measured characteristics in the laminar mode flow as follows: frequency 25 kHz; applied voltage 11.2 kV; flow rate, 2.4 slm; power, 2.34 W; jet temperature, 340 K; jet length, 11.5 mm; jet width, 1.6 mm; energy, 96 mJ; and Reynolds number, 2819. Under all the measured characteristics of maximum laminar flow mode with the flow rate, 2.4 slm, the optical emission spectroscopy data of APPJ for dry Ar discharge and for wet argon (coupled with TiO2 precursor with the emerging jet) were measured. Survival curves of live microbes confirmed that as TiO2 precursor concentration increases in the range from 0 to 0.5 g l−1, the deactivation rate of E. coli increases due to the photocatalytic disinfection performance, because of the TiO2 precursor concentrations dosage enhances the effect of the incident plume of the non-thermal jet, leading to the generation of more active substances that can be absorbed by the cells causing acceleration of the sterilization efficiency.
Remarkable enhancement of upconversion emissions by thermal stimulation in Er-doped Yb2Mo3O12 microcrystals
Authors: Chen Hao , Li Denghao , Zhang Libin , Bai Gongxun , Xu Shiqing , Chen Liang
Published: April 2021

Lanthanide-doped luminescent materials have drawn great attention due to their lighting, display, and sensing applications. However, their emission intensity usually decreases with increasing temperature, leading to a weaken performance. In this work, the Er3+-doped Yb2Mo3O12 microcrystals with optical temperature sensing properties have been synthesized by a solid-phase sintering route. Under the excitation of a 980 nm laser, the sample shows enhanced upconversion emissions as temperature rises, which is attributed to the negative thermal expansion in the crystal structure and enhanced crystal field strength. At the same time, based on the luminous intensity ratio of two thermally coupled energy levels (Er3+:2H11/2,4S3/2), the temperature sensing properties of the prepared microcrystals were studied. This work achieves high SR (1207.4/T) in the range from 313 to 573 K, and it is accompanied by a 21-fold enhancement of the upconversion emission intensity. As a whole, this is an excellent material that can be used for optical temperature sensing with highly sensitive and enhanced upconversion emission.
Thermodynamic, transport, and structural properties of hydrophobic deep eutectic solvents composed of tetraalkylammonium chloride and decanoic acid
Authors: S. Salehi Hirad , Celebi Alper T. , Vlugt Thijs J. H. , Moultos Othonas A.
Published: April 2021

With the emergence of hydrophobic deep eutectic solvents (DESs), the scope of applications of DESs has been expanded to include situations in which miscibility with water is undesirable. Whereas most studies have focused on the applications of hydrophobic DESs from a practical standpoint, few theoretical works exist that investigate the structural and thermodynamic properties at the nanoscale. In this study, Molecular Dynamics (MD) simulations have been performed to model DESs composed of tetraalkylammonium chloride hydrogen bond acceptor and decanoic acid hydrogen bond donor (HBD) at a molar ratio of 1:2, with three different cation chain lengths (4, 7, and 8). After fine-tuning force field parameters, densities, viscosities, self-diffusivities, and ionic conductivities of the DESs were computed over a wide temperature range. The liquid structure was examined using radial distribution functions (RDFs) and hydrogen bond analysis. The MD simulations reproduced the experimental density and viscosity data from the literature reasonably well and were used to predict diffusivities and ionic conductivities, for which experimental data are scarce or unavailable. It was found that although an increase in the cation chain length considerably affected the density and transport properties of the DESs (i.e., yielding smaller densities and slower dynamics), no significant influence was observed on the RDFs and the hydrogen bonds. The self-diffusivities showed the following order for the mobility of the various components: HBD > anion > cation. Strong hydrogen bonds between the hydroxyl and carbonyl groups of decanoic acid and between the hydroxyl group of decanoic acid and chloride were observed to dominate the intermolecular interactions.
The demographics of knowledge, attitudes and emotions toward coyotes
Authors: Vaske Jerry J. , Sponarski Carly C.
Published: April 2021

Abstract Context A coyote-caused human fatality in Cape Breton Highlands National Park of Canada (CBHNPC) occurred in 2009. Because CBHNPC is federally protected, rangers have a limited number of management options for dealing with human–coyote conflict. The park initiated the present study to understand the publics’ acceptance of coyotes. Aims This article examined relationships between each of four independent variables (respondent type (resident vs visitor), sex, age, education) and each of four dependent variables (knowledge, attitude, two emotions) related to coyotes in CBHNPC. Researchers have repeatedly suggested that demographics are related to cognitions and emotions toward wildlife. Managers can use demographic findings to target education campaigns to specific stakeholders. Methods Survey data were obtained from (a) residents living around CBHNPC (n = 556, response rate = 70%), and (b) visitors hiking two popular trails in CBHNPC (n = 443, response rate = 60%). Key results All four independent variables were related to knowledge. Visitors were more knowledgeable about coyotes than were residents. Females were more knowledgeable than were males. Younger respondents were more knowledgeable than were older individuals. All education categories differed from each other. Findings for the attitude construct were similar. Residents held negative attitudes toward coyotes, whereas visitors were slightly positive. Males and females both held negative attitudes. The youngest age category held a positive attitude, whereas the oldest group was the most negative. Respondents with a high-school degree had a negative attitude; those with a college degree held a positive attitude. For the first emotion concept, residents were more emotional than were visitors. Males were more emotional than were females, and high-school graduates were more emotional than were college graduates. For the second emotion, there were statistical differences between residents and visitors, as well as between males and females. However, age and education were not related to this scenario. Conclusions Although there were statistical differences for 13 of 16 tests, over 80% of the effect sizes were minimal and there were interaction effects among the four demographic variables. Implications Findings highlighted complexities managers should consider when designing communication strategies aimed at influencing stakeholders’ knowledge of and attitudes and emotions toward wildlife.
Multiple independent recombinations led to hermaphroditism in grapevine
Authors: Zou Cheng , Massonnet Mélanie , Minio Andrea , Patel Sagar , Llaca Victor , Karn Avinash , Gouker Fred , Cadle-Davidson Lance , Reisch Bruce , Fennell Anne , Cantu Dario , Sun Qi , Londo Jason P.
Published: April 2021

Significance

We studied the grape sex-determining region (SDR) in 12Vitisgenomes and demonstrated its conservation across 556 genotypes including 193 accessions from 47 world-wide wild grapevine species and 363 accessions of cultivated grapevine. Although the grape SDR is recombination free in all wild species, we found two distinct hermaphrodite (H) haplotypes (H1 and H2) among the cultivated grapevines, both chimeras of male (M) and female (f) haplotypes. The two independent recombinations carry different genetic signatures which long predate the domestication of grapevine, suggesting independent evolutions of this trait in wild European grapevine gene pools prior to human domestication.
Abutilon indicum (country mallow).
Authors: Vélez-Gavilán Jeanine
Published: April 2021

A datasheet on Abutilon indicum covering, as an economically important tree, its taxonomy, importance, silviculture, distribution, biology and ecology, uses, products and pests.
Spatiotemporal coordination of Greatwall-Endos-PP2A promotes mitotic progression
Authors: Larouche Myreille , Kachaner David , Wang Peng , Normandin Karine , Garrido Damien , Yao Changfu , Cormier Maxime , Johansen Kristen M. , Johansen Jørgen , Archambault Vincent
Published: April 2021

Mitotic entry involves inhibition of protein phosphatase 2A bound to its B55/Tws regulatory subunit (PP2A-B55/Tws), which dephosphorylates substrates of mitotic kinases. This inhibition is induced when Greatwall phosphorylates Endos, turning it into an inhibitor of PP2A-Tws. How this mechanism operates spatiotemporally in the cell is incompletely understood. We previously reported that the nuclear export of Greatwall in prophase promotes mitotic progression. Here, we examine the importance of the localized activities of PP2A-Tws and Endos for mitotic regulation. We find that Tws shuttles through the nucleus via a conserved nuclear localization signal (NLS), but expression of Tws in the cytoplasm and not in the nucleus rescues the development of tws mutants. Moreover, we show that Endos must be in the cytoplasm before nuclear envelope breakdown (NEBD) to be efficiently phosphorylated by Greatwall and to bind and inhibit PP2A-Tws. Disrupting the cytoplasmic function of Endos before NEBD results in subsequent mitotic defects. Evidence suggests that this spatiotemporal regulation is conserved in humans.
Dynamical diffeomorphisms
Authors: Ferrero Renata , Percacci Roberto
Published: April 2021

We construct a general effective dynamics for diffeomorphisms of spacetime, in a fixed external metric. Though related to familiar models of scalar fields as coordinates, our models have subtly different properties, both at kinematical and dynamical level. The energy–momentum (EM) tensor consists of two independently conserved parts. The background solution is the identity diffeomorphism and the EM tensor of this solution gives rise to an effective cosmological constant.
Reissner–Nordström geometry counterpart in semiclassical gravity
Authors: Arrechea Julio , Barceló Carlos , Carballo-Rubio Raúl , Garay Luis J
Published: April 2021

We compute the renormalized stress–energy tensor (RSET) of a massless minimally coupled scalar field in the regularized Polyakov approximation, as well as its backreaction, on the classical Reissner–Nordström spacetime. The complete set of solutions of the semiclassical self-consistent equations is obtained and compared with their classical counterparts. The semiclassical Reissner–Nordström family involves three kinds of geometries that arise depending on the charge-to-mass ratio of the spacetime. In the under-charged regime, the geometry has its external horizon replaced by a wormhole neck that leads to a singular asymptotic region at finite proper distance. The over-charged regime reveals a naked singularity surrounded by a cloud of (infinite) mass coming from the quantized field. Between both behaviours there is a separatrix solution reminiscent of the extremal black hole classical geometry. As the RSET over an extremal horizon is finite, the semiclassical backreaction does not get rid of the horizon. Nonetheless, we show that the resulting horizon is singular.
The physical origin of Schrödinger equation
Authors: Yan Xiao-Bo
Published: April 2021

Quantum mechanics is one of the basic theories of modern physics. Here, the famous Schrödinger equation and the differential operators representing mechanical quantities in quantum mechanics are derived, just based on the principle that the translation invariance (symmetry) of a system in Hamiltonian mechanics should be preserved in quantum mechanics. Moreover, according to the form of the differential operators, the commutation relation in quantum mechanics between the generalized coordinate and the generalized momentum can be directly obtained. We believe that the results in this paper are very useful for understanding the physical origin of quantum mechanics.
Efficient ground state cooling of a membrane by the combination of continuous-wave field and pulses
Authors: Chen Zhi Xin , He Bing , Lin Qing
Published: April 2021

We present an approach that realizes the ground state cooling of the membrane-in-middle optomechanical system. Instead of straightforwardly using the continuous-wave (CW) or pulsed external drives, we consider the combinations of them for having a more efficient cooling process. Due to the dynamical nature of the joint action of both CW and pulse fields, it is necessary to explore the real-time evolutions of the system under various conditions, from which the optimal cooling can be found. Given such setup, the cooling limit previously discovered for the simple optomechanical systems under a single CW drive can be easily broken. The achieved cooling effect indicated by a defined cooling rate is one or more order lower than the cooling limit of a simple optomechanical systems, thus providing an efficient way of ground state cooling. Furthermore, the ground state cooling can be realized for a membrane with much lower mechanical quality factor and with the external drives of the lower intensities, to considerably relax the requirements for optomechanical cooling with the current experimental technology.
Theoretical investigations of e
±
–CO scattering
Authors: Billah M Masum , H Khandker Mahmudul , Shorifuddoza M , Sayed M A , Watabe Hiroshi , Haque A K F , Uddin M Alfaz
Published: April 2021

The differential, integrated elastic, total, momentum transfer, viscosity cross sections and spin-polarization for electron and positron elastic scattering from carbon monoxide (CO) molecule are calculated for the energy range of 1 eV–10 keV. The work also includes the calculations of inelastic and total ionization cross sections for the same scattering system. Calculations of the above scattering observables for CO over such a wide range of energy are reported for the first time. Single scattering independent atom model (IAM) and the screening correction within the same framework, are used for the present analysis. Dirac partial wave analysis is used to calculate the phase-shifts required for the generation of the scattering observables, using a complex optical model potential. Comparison of our calculated results with the available experimental observations and other theoretical calculations is presented. The screening corrected independent atom model is found to provide better description of the results than the IAM.
Probing adsorbates on La1−x
Sr
x
NiO3−δ
surfaces under humid conditions: implications for the oxygen evolution reaction
Authors: Carvalho O Quinn , Adiga Prajwal , Wang Le , Liu Jishan , Jia Endong , Du Yingge , Nemšák Slavomir , Stoerzinger Kelsey A
Published: April 2021

Earth-abundant nickel-containing perovskite oxides (ANiO3) are highly active materials for the oxygen evolution reaction (OER). The strong nickel-oxygen (Ni–O) covalency, tunable by A-site chemical substitution, contributes to both bulk and surface material properties like the formation of oxygen vacancies (v
••

O
) and OER activity. Here we quantify the coverage of OER relevant adsorbates on a series of La1−x
Sr
x
NiO3−δ
(LSNO, 0 ⩽ x ⩽ 0.5) epitaxial thin films exposed to humid environments by ambient pressure x-ray photoelectron spectroscopy. While all LSNO film compositions investigated here have comparable hydroxide coverages at the relative humidities (RHs) probed (1.5 × 10−5 – 0.2%RH), the amount of under-coordinated surface oxygen increases notably with Sr content. We interpret differences in the free energy of adsorption (ΔG
ads,i
) of these OER intermediates, inferred from adsorption isotherms, in the context of proposed v
••

O
-mediated OER mechanisms, consistent with the pH-dependent OER activity observed here for LSNO. We find that Sr incorporation enhances the affinity of LSNO surfaces for these under-coordinated oxygen species, in line with calculations in the literature.
Core−shell coaxially structured NiCo2S4@TiO2 nanorod arrays as advanced electrode for solid-state asymmetric supercapacitors
Authors: Qi Fangya , Li Han , Yang Fan , Sun Zhipeng
Published: April 2021

An integrated electrode of core–shell coaxially structured NiCo2S4@TiO2 nanorod arrays/carbon cloth (NiCo2S4@TiO2@CC) have been fabricated, via a two-step hydrothermal method. Comprehensive structural and compositional analyzes are performed to understand the effects of the NiCo2S4 shell on the TiO2 core. Such core–shell arrays structure can significantly provide abundant electroactive sites for redox reactions, convenient ion transport paths, and favorable structure stability. The NiCo2S4@TiO2@CC electrode represents a splendid specific capacitance (650 F g−1 at 1 A g−1) and enhanced cycling stability (capacitance retention of 97% over 10 000 cycles at 5 A g−1). Additionally, the assembled NiCo2S4@TiO2@CC//CNT@CC solid-state asymmetric supercapacitors exhibit a maximal energy density of 0.6 mWh cm−3 at 32.4 W cm−3, and topping cycling stability (85% capacitance retention after 5000 cycles at 5 mA cm−2). The results demonstrate that the well-designed NiCo2S4@TiO2@CC presented in this work are applicable for the development of electrode materials in energy storage devices.
Simulations of COMPASS vertical displacement events with a self-consistent model for halo currents including neutrals and sheath boundary conditions
Authors: Artola F J , Loarte A , Matveeva E , Havlicek J , Markovic T , Adamek J , Cavalier J , Kripner L , Huijsmans G T A , Lehnen M , Hoelzl M , Panek R ,   the COMPASS team,   the JOREK team
Published: April 2021

The understanding of the halo current properties during disruptions is key to design and operate large scale tokamaks in view of the large thermal and electromagnetic loads that they entail. For the first time, we present a fully self-consistent model for halo current simulations including neutral particles and sheath boundary conditions. The model is used to simulate vertical displacement events (VDEs) occurring in the COMPASS tokamak. Recent COMPASS experiments have shown that the parallel halo current density at the plasma-wall interface is limited by the ion saturation current during VDE-induced disruptions. We show that usual magneto-hydrodynamic boundary conditions can lead to the violation of this physical limit and we implement this current density limitation through a boundary condition for the electrostatic potential. Sheath boundary conditions for the density, the heat flux, the parallel velocity and a realistic parameter choice (e.g. Spitzer’s resistivity and Spitzer–Härm parallel thermal conductivity) extend present VDE simulations beyond the state of the art. Experimental measurements of the current density, temperature and heat flux profiles at the COMPASS divertor are compared with the results obtained from axisymmetric simulations. Since the ion saturation current density (

J

sat

) is shown to be essential to determine the halo current profile, parametric scans are performed to study its dependence on different quantities such as the plasma resistivity and the particle and heat diffusion coefficients. In this respect, the plasma resistivity in the halo region broadens significantly the

J

sat

profile, increasing the halo width at a similar total halo current.
Detection of 1H NMR signal in a trapped magnetic field of a compact tubular MgB2 superconductor bulk
Authors: Takahashi Yuhei , Naito Tomoyuki , Nakamura Takashi , Takahashi Masato
Published: April 2021

We measured 1H nuclear magnetic resonance (NMR) spectra from silicon rubber in a magnetic field trapped by a compact tubular MgB2 superconductor bulk magnet (60 mm outer diameter, 40 mm inner diameter, and 60 mm height) which was magnetized by field-cooled magnetization from an applied field,

B

a
p
p

, of 0.4778 T at 20 K. The sharpest 1H NMR spectrum of the resonant frequency,

f

R

, of 20.314 MHz, which corresponded to a field strength of 0.4771 T, was observed at 1 mm below the center of the bore of the MgB2 tube. The homogeneity of the trapped field was within 100 ppm between z 

=

−2 and +2 mm along the central z-axis, which was evaluated by the position-dependent

f

R

. No change in the trapped field was observed for about 25 d, which corresponded to a decay rate of less than 0.1 ppb h−1. The obtained results suggest that the MgB2 bulk magnet is a promising candidate for a magnetic pole in an NMR apparatus.
A fractal-fractional order Atangana-Baleanu model for Hepatitis B virus with asymptomatic class
Authors: Zhong Jian-Feng , Gul Nadia , Bilal Rubi , Xia Wei-Feng , Altaf Khan Muhammad , Muhammad Taseer , Islam Saeed
Published: April 2021

Hepatitis B is still a major issue in most countries of the world. Due to many death and infection cases, the disease becoming a life-threatening issue and needs proper attention for its eradication. The main aim of this study is to design a new mathematical model with an asymptomatic class based on clinical investigations to study its dynamics. The asymptomatic carriers class do not possess symptoms but infect other healthy people. This new idea has been utilized for the first time in the present analysis with fractal-fractional operators. We formulate the model basically in integer-order and then apply the fractal-fractional derivative in Atangana-Baleanu type. For the fractional model, we study the related results and their numerical solution. Further, we apply the fractal operator together with fractional derivative which is known as fractal-fractional derivative in the Atangana-Baleanu case, and present the model. For the numerical solution, we provide a scheme based on the Adams-Bashforth method and obtained the results graphically. With various choices of the fractal and fractional orders, we present various graphical solutions. The model parameters that can reduce the infection of Hepatitis B are shown graphically. The disease in the population can be minimized well by taking into consideration the model important parameters. The important parameters and their effect have been shown graphically.
Equivalent complex impedance of n-order RLC network
Authors: Chen Hai-Xiang , Wang Ming-Yue , Chen Wan-Jiao , Fang Xin-Yu , Tan Zhi-Zhong
Published: April 2021

Complex n-order complex impedance network is a kind of common complex problems. The electrical characteristics of its equivalent complex impedance are usually complex. We consider a kind of complex impedance network model of two terminal ladder network with complex parameters, and investigate the characteristics of equivalent complex impedance by deriving the analytical formula of equivalent complex impedance. The main research methods are as follows: firstly, the equivalent model is constructed. Secondly, the nonlinear difference equation model is established according to the equivalent model, and then the universal law of the equivalent complex impedance of n-ladder network is given by studying the solution of the nonlinear difference equation. Finally, the specific cases of LC network and non-ideal transmission line are studied respectively, and compared with the relevant results.
Seesaw neutrino dark matter by freeze-out
Authors: Jaramillo Carlos , Lindner Manfred , Rodejohann Werner
Published: April 2021

We investigate whether right-handed neutrinos can play the
role of the dark matter of the Universe and be generated by the
freeze-out production mechanism. In the standard picture, the
requirement of a long lifetime of the right-handed neutrinos implies
a small neutrino Yukawa coupling. As a consequence, they never reach
thermal equilibrium, thus prohibiting production by freeze-out. We
note that this limitation is alleviated if the neutrino Yukawa
coupling is large enough in the early Universe to thermalize the
sterile neutrinos, and then becomes tiny at a certain moment, which
makes them drop out of equilibrium. As a concrete example
realization of this framework, we consider a Froggatt-Nielsen model
supplemented by an additional scalar field which obeys a global
symmetry (not the flavour symmetry). Initially, the vacuum
expectation value of the flavon is such, that the effective neutrino
Yukawa coupling is large and unsuppressed, keeping them in thermal
equilibrium. At some point the new scalar also gets a vacuum
expectation value that breaks the symmetry. This may occur in such a
way that the vev of the flavon is shifted to a new (smaller)
value. In that case, the Yukawa coupling is reduced such that the
sterile neutrinos are rendered stable on cosmological time scales.
We show that this mechanism works for a wide range of sterile
neutrino masses.
A solution to the de Sitter swampland conjecture versus inflation tension via supergravity
Authors: Atli Ugur , Guleryuz Omer
Published: April 2021

The methods of supergravity allow us to derive a multi-field F-term potential. Using this, we denote a generic and non-positive single-field F-term potential. We insert our theory into the scalar-gravity part of the (2,1|1) invariant superconformal action. That action leads us to a de Sitter solution at the inflationary trajectory. One can denote stabilization of fields in terms of the Kähler kinetic terms and single-field slow-roll inflation parameters. We combine these with the de Sitter swampland conjecture to generate a bounded conjecture. This approach allowed us to show that the single field slow-roll inflation works in harmony with bounded de Sitter conjecture for any concave inflation potential.
Mechanism of defect evolution in H+ and He+ implanted InP*
Authors: Liu Ren-Jie , Lin Jia-Jie , Daghbouj N , Sun Jia-Liang , You Tian-Gui , Gao Peng , Sun Nie-Feng , Liao Min
Published: April 2021

The defect evolution in InP with the 75 keV H+ and 115 keV He+ implantation at room temperature after subsequent annealing has been investigated in detail. With the same ion implantation fluence, the He+ implantation caused much broader damage distribution accompanied by much higher out-of-plane strain with respect to the H+ implanted InP. After annealing, the H+ implanted InP did not show any blistering or exfoliation on the surface even at the high fluence and the H2 molecules were stored in the heterogeneously oriented platelet defects. However, the He molecules were stored into the large bubbles which relaxed toward the free surface, creating blisters at the high fluence.
A novel decoding method for motor imagery tasks with 4D data representation and 3D convolutional neural networks
Authors: Li Ming-ai , Ruan Zi-wei
Published: April 2021

Objective. Motor imagery electroencephalography (MI-EEG) produces one of the most commonly used biosignals in intelligent rehabilitation systems. The newly developed 3D convolutional neural network (3DCNN) is gaining increasing attention for its ability to recognize MI tasks. The key to successful identification of movement intention is dependent on whether the data representation can faithfully reflect the cortical activity induced by MI. However, the present data representation, which is often generated from partial source signals with time-frequency analysis, contains incomplete information. Therefore, it would be beneficial to explore a new type of data representation using raw spatiotemporal dipole information as well as the possible development of a matching 3DCNN. Approach. Based on EEG source imaging and 3DCNN, a novel decoding method for identifying MI tasks is proposed, called ESICNND. MI-EEG is mapped to the cerebral cortex by the standardized low resolution electromagnetic tomography algorithm, and the optimal sampling points of the dipoles are selected as the time of interest to best reveal the difference between any two MI tasks. Then, the initial subject coordinate system is converted to a magnetic resonance imaging coordinate system, followed by dipole interpolation and volume down-sampling; the resulting 3D dipole amplitude matrices are merged at the selected sampling points to obtain 4D dipole feature matrices (4DDFMs). These matrices are augmented by sliding window technology and input into a 3DCNN with a cascading architecture of three modules (3M3DCNN) to perform the extraction and classification of comprehensive features. Main results. Experiments are carried out on two public datasets; the average ten-fold CV classification accuracies reach 88.73% and 96.25%, respectively, and the statistical analysis demonstrates outstanding consistency and stability. Significance. The 4DDFMs reveals the variation of cortical activation in a 3D spatial cube with a temporal dimension and matches the 3M3DCNN well, making full use of the high-resolution spatiotemporal information from all dipoles.
The impact of CT image parameters and skull heterogeneity modeling on the accuracy of transcranial focused ultrasound simulations
Authors: Montanaro Hazael , Pasquinelli Cristina , Lee Hyunjoo J , Kim Hyunggug , Siebner Hartwig R , Kuster Niels , Thielscher Axel , Neufeld Esra
Published: April 2021

Objective. Low-intensity transcranial ultrasound stimulation (TUS) is a promising non-invasive brain stimulation (NIBS) technique. TUS can reach deeper areas and target smaller regions in the brain than other NIBS techniques, but its application in humans is hampered by the lack of a straightforward and reliable procedure to predict the induced ultrasound exposure. Here, we examined how skull modeling affects computer simulations of TUS. Approach. We characterized the ultrasonic beam after transmission through a sheep skull with a hydrophone and performed computed tomography (CT) image-based simulations of the experimental setup. To study the skull model’s impact, we varied: CT acquisition parameters (tube voltage, dose, filter sharpness), image interpolation, segmentation parameters, acoustic property maps (speed-of-sound, density, attenuation), and transducer-position mismatches. We compared the impact of modeling parameter changes on model predictions and on measurement agreement. Spatial-peak intensity and location, total power, and the Gamma metric (a measure for distribution differences) were used as quantitative criteria. Modeling-based sensitivity analysis was also performed for two human head models. Main results. Sheep skull attenuation assignment and transducer positioning had the most important impact on spatial peak intensity (overestimation up to 300%, respectively 30%), followed by filter sharpness and tube voltage (up to 20%), requiring calibration of the mapping functions. Positioning and skull-heterogeneity-structure strongly affected the intensity distribution (gamma tolerances exceeded in

>

80%, respectively

>

150%, of the focus-volume in water), necessitating image-based personalized modeling. Simulation results in human models consistently demonstrate a high sensitivity to the skull-heterogeneity model, attenuation tuning, and transducer shifts, the magnitude of which depends on the underlying skull structure complexity. Significance. Our study reveals the importance of properly modeling the skull-heterogeneity and its structure and of accurately reproducing the transducer position. The results raise red flags when translating modeling approaches among clinical sites without proper standardization and/or recalibration of the imaging and modeling parameters.
Development of an “in situ” calibration methodology to activity meters
Authors: Kuahara L T , Martins E W , Potiens M P A
Published: April 2021

The performance of a safety and efficient practice of a nuclear medicine service depends, among other factors, on a complete quality control program, especially in the case of the radionuclide activity measuring instrument, the activimeter. Several factors may influence the accuracy of the measurements performed with an activimeter, and the largest sources of errors are related to the types of containers that contain radiopharmaceuticals (eg, thickness, size and volume). A complete quality control program should include the calibration of all measurement instruments used in the procedure. However, in Brazil, the actual standard that establishes the requirements of radiological protection for nuclear medicine services (NMS), does not include the calibration of the activimeter. Considering that these instruments, for various reasons, are difficult to remove for sending to a Calibration Service, the purpose of this work is to develop a methodology for activimeter calibration that can be applied “in situ” to the most used radiopharmaceutical, 99mTc.
Estimation of measurement uncertainty in the EDXRF spectrometry of stainless steel
Authors: Krummenauer A , Dias P R , Veit H M
Published: April 2021

The uncertainty in the analysis of nine elements in stainless steels performed with the NITON spectrometer was estimated. Initially, an Ishikawa diagram was used to describe the main sources of uncertainty. After calculating the standard uncertainties of these sources, they were combined to determine the combined standard uncertainty and the expanded uncertainty for each element. An uncertainty contribution graph was developed to assist in analyzing the influences of uncertainty sources on the final value of combined standard uncertainty. A simple uncertainty can be attributed to each element and the calibration curve is a very significant uncertainty source.