bluuebunny/crossref_metadata_2025 huggingface dataset:
U-Net-based approach for automatic lung segmentation in electrical impedance tomography
Authors: Ko Yen-Fen , Cheng Kuo-Sheng
Published: January 2021

Objective. Electrical impedance tomography (EIT) is a non-invasive technique that constitutes a promising tool for real-time imaging and long-term monitoring of the ventilation distribution at bedside. However, clinical monitoring and diagnostic evaluations depend on various methods to assess ventilation-dependent parameters useful for ventilation therapy. This study develops an automatic, robust, and rapidly accessible method for lung segmentation that can be used to define appropriate regions-of-interest (ROIs) within EIT images. Approach. To date, available methods for patients with defected lungs have the disadvantage of not being able to identify lung regions because of their poor ventilation responses. Furthermore, the challenges related to the identification of lung areas in EIT images are attributed to the low spatial resolution of EIT. In this study, a U-Net-based automatic lung segmentation model is used as a postprocessor to transform the original EIT image to a lung ROI image and refine the inherent conductivity distribution of the original EIT image. The trained U-Net network is capable of performing an automatic segmentation of conductivity changes in EIT images without requiring prior information. Main results. The experimental design of this study was based on a finite element method (FEM) phantom used to assess the feasibility and effectiveness of the proposed method, and evaluation of the trained models on the test dataset was performed using the Dice similarity coefficient (DSC) and the mean absolute error (MAE). The FEM experimental results yielded values of 0.0065 for MAE, and values >0.99 for DSC in simulations. Significance. The use of a deep-learning-based approach attained automatic and convenient segmentation of lung ROIs into distinguishable images, which represents a direct benefit for regional lung ventilation-dependent parameter extraction and analysis. However, further investigations and validation are warranted in real human datasets with different physiology conditions with CT cross-section dataset to refine the suggested model.
Estimating blood flow velocity using time-resolved 3D angiography and a derived physical law of contrast media
Authors: Chen Ko-Kung , Lin Chung-Jung , Guo Wan-Yuo , Chu Wei-Fa , Wu Yu-Te
Published: January 2021

Objective. Four-dimensional (4D) digital subtraction angiography (DSA) offers a method for evaluating hemodynamics. It is, however, unclear how the delivered contrast medium interacts with the physiological blood flow, and how hemodynamic information may be inferred from the mixture of the contrast medium and blood. In this study, we present a theoretical explanation of contrast dynamics, and an accompanying algorithm for estimating blood flow velocity. Approach. We retrospectively recruited 23 patients who underwent both 4D DSA and magnetic resonance (MR) phase-contrast imaging. The 4D DSA-reconstructed contrast dynamics were first studied for the internal carotid arteries. Using physical laws governing fluid motion within a curved tube, we showed that the reconstructed contrast dynamics obeyed a simple advection equation. We then proposed an algorithm for estimating the contrast dynamics using angiographic data, and subsequently estimated the axial blood flow velocity using an advection equation. Main results. The estimated velocities were compared using three techniques: the Fourier technique, Lin’s method, and MR phase contrast. Testing with noise-corrupted artificial data showed that the proposed algorithm was noise resistant. The velocities of 23 patients computed by 4D DSA using the proposed algorithm showed a moderate correlation with the MR phase contrast (r = 0.61), and good correlations with the other two techniques (r = 0.75 and r = 0.72). Significance. The proposed algorithm and has been applied to blood vessel segments with poor signal-to-noise ratios and axial lengths of less than 3 cm, and has a physical basis for computing axial flow velocities using an advection equation. The results of the proposed algorithm are consistent with existing methods.
Solution-based CdS thin film transistors with low temperature-processed Al2O3-GPTMS-PMMA as hybrid dielectric gate
Authors: Meza-Arroyo J , Chandra Sekhar Reddy K , Syamala Rao M G , Garibay-Martínez F , de Urquijo-Ventura M S , Ramírez-Bon R
Published: January 2021

Herein, we report the low-temperature fabrication process and the electrical response of n-type cadmium sulfide (CdS)-based thin-film transistors (TFTs) with an Al2O3-GPTMS-polymethylmethacrylate (PMMA) hybrid dielectric gate. The TFTs with bottom-gate structure were assembled on ITO (indium-tin-oxide)-coated glass substrates employing solution processes for the deposition of both the dielectric gate and semiconductor layers. The hybrid dielectric layers were deposited by the sol-gel process and subsequently annealed at 150 °C. The FTIR and XPS analysis of the hybrid films demonstrated a proper link between Al2O3 and PMMA through the cross-linking agent 3-glycidoxy(propyltrimethoxysilane) silane (GPTMS). The surface characteristics were obtained by contact angle and atomic force microscope studies, the results show that the surface of hybrid films displays a hydrophobic behavior with a smooth surface. The CdS active layer was deposited on the hybrid dielectric gate at room temperature by a simple photochemical bath deposition using a 313 nm UV lamp. The CdS-TFTs showed outstanding electrical performance with a low threshold voltage of 1.3 V, I
ON
/I
OFF of 104, subthreshold swing of 440 mV dec−1, and remarkable high mobility value of 64.4 cm2 V−1 s−1. Ultimately, the feature of these completely solution-based CdS TFTs is the maximum processing temperature of 150 °C, and the findings of this study are very promising for potential low-cost solution-processed TFTs.
Wearable pressure sensor based on MXene/single-wall carbon nanotube film with crumpled structure for broad-range measurements
Authors: Fan Zhihong , Zhang Lei , Tan Qiulin , Yao Xue , Lin Baimao , Wang Ya , Xiong Jijun
Published: January 2021

High-performance flexible pressure sensors are attracting great interest owing to their potential applications for electronic skins, human–machine interfaces, and biomedical diagnostics. However, there remain significant challenges for the fabrication of low-cost and high-sensitivity sensors. Here, we report the preparation of Ti3C2T
x
MXene/single-wall carbon nanotube (SWNT) composite films through vacuum-assisted filtration followed by thermal shrinkage. SWNTs can effectively prevent MXenes from stacking and improve the electrical performance of the films. The films are used as a flexible piezoresistive sensor for pressures ranging from 33 Pa to 130 kPa. And experimental test results indicate that the fabricated pressure sensors have high sensitivity (116.15 kPa−1 below 40 kPa and 12.7 kPa−1 at 40–130 kPa), a fast response time of 13 ms, and long-term stability over 6000 periods. The sensor can be used to monitor human physiological signals, such as finger movements, voice detection, and wrist pulse in real-time. Moreover, a 4 × 4 sensor array was successfully applied in the pressure distribution mapping of different objects, indicating that the pressure sensor can be applied in electronic skin, medical devices, and other wearable devices.
Control of rejection frequency and density of output spectrum by programming nonuniform two channels with ternary fluidic system
Authors: Park Eiyong , Lim Sungjoon
Published: January 2021

The growth of multi-functional wireless systems has made selecting the operation frequency and rejecting unwanted frequencies very difficult because of the interferences in dense spectra. Compared to conventional electronic tuning devices, microfluidic channels have great potential because of the greater design freedom and fewer parasitic effects. Previously, single or uniform microfluidic channels have been used for microwave sensors, antennas, or filters. In this study, a rejection frequency control filter was constructed by programming two nonuniform channels with a ternary fluidic system. To obtain two nonuniform channels with a wide tuning range, a novel defected ground cavity structure was designed. When three different fluids are used as ‘0’, ‘1’, and ‘2’ inputs for the ternary fluidic system, it outputs nine different rejection frequencies. The density of the output spectrum can be controlled by designing either uniform or nonuniform channels in the proposed fluidic system. For instance, uniform channels produce sparse frequency channels between 1.95 and 3.55 GHz. By contrast, the nonuniform channels produce dense and successive frequency spectra ranging from 2.5 to 3.32 GHz. Thus, the tuning range of uninform channels is wider than that of nonuniform channels.
Heating and de-icing function in conductive concrete and cement paste with the hybrid addition of carbon nanotubes and graphite products
Authors: Farcas C , Galao O , Navarro R , Zornoza E , Baeza F J , Del Moral B , Pla R , Garcés P
Published: January 2021

This paper aims to study the viability of conductive cement paste and conductive concrete with the hybrid addition of carbon nanotubes (CNT) and graphite powder (GP) as a self-heating material for heating, ice formation prevention and de-icing in pavements. Different heating tests, ice-preventing tests and de-icing tests were performed with cement paste and concrete specimens. Results confirm that the conductive cement composites studied, with the addition of 1% CNT + 5% GP, exhibited heating, de-icing and ice-prevention properties, when applying constant AC/DC voltages between the two end sides of each specimen, with relatively low energy consumption. The main contribution of this work is to achieve a sufficient conductivity level for the development of the heating and de-icing function using this hybrid addition in concrete, which has not been used so far, in order to be applied in real concrete structures.
Effective waves for random three-dimensional particulate materials
Authors: Gower Artur L , Kristensson Gerhard
Published: January 2021

How do you take a reliable measurement of a material whose microstructure is random? When using wave scattering, the answer is often to take an ensemble average (average over time or space). By ensemble averaging we can calculate the average scattered wave and the effective wavenumber. To date, the literature has focused on calculating the effective wavenumber for a plate filled with particles. One clear unanswered question was how to extend this approach to a material of any geometry and for any source. For example, does the effective wavenumber depend on only the microstructure, or also on the material geometry? In this work, we demonstrate that the effective wavenumbers depend on only microstructure, though beyond the long wavelength limit there are multiple effective wavenumbers for one fixed incident frequency. We show how to calculate the average wave scattered from a random particulate material of any shape, and for broad frequency ranges. As an example, we show how to calculate the average wave scattered from a sphere filled with particles.
Multipoint connection by long-range density interaction and short-range distance rule
Authors: Gentile Francesco
Published: January 2021

The performance of a system is influenced by the way its elements are connected. Networks of cells with high clustering and short paths communicate more efficiently than random or periodic networks of the same size. While many algorithms exist for generating networks from distributions of points in a plane, most of them are based on the oversimplification that a system’s components form connections in proportion to the inverse of their distance. The Waxman algorithm, which is based on a similar assumption, represents the gold standard for those who want to model biological networks from the spatial layout of cells. This assumption, however, does not allow to reproduce accurately the complexity of physical or biological systems, where elements establish both short and long-range connections, the combination of the two resulting in non-trivial topological features, including small-world characteristics. Here, we present a wiring algorithm that connects elements of a system using the logical connective between two disjoint probabilities, one correlated to the inverse of their distance, as in Waxman, and one associated to the density of points in the neighborhood of the system’s element. The first probability regulates the development of links or edges among adjacent nodes, while the latter governs interactions between cluster centers, where the density of points is often higher. We demonstrate that, by varying the parameters of the model, one can obtain networks with wanted values of small-world-ness, ranging from ∼1 (random graphs) to ∼14 (small world networks).
A comparative study between GGA, WC-GGA, TB-mBJ and GGA + U approximations on magnetocaloric effect, electronic, optic and magnetic properties of BaMnS2 compound: DFT calculations and Monte Carlo simulations
Authors: Kadim G , Masrour R , Jabar A
Published: January 2021

The magnetocaloric effect, electronic, optical and magnetic properties of BaMnS2 are studied using the Wu-Cohen-Generalized Gradients Approximation (WC-GGA), GGA, Tran and Blaha modified Becke-Johnson potential (TB-mBJ) and GGA + U(U is the Hubbard potential) approximations and Monte Carlo simulations. BaMnS2 has an antiferromagnetic behavior and a semiconductor character with a narrow band gap follows the trend WC-GGA < GGA < mBJ < GGA + U. The GGA + U transformed and increased the nature of the band gap, causing an apparent change in physical properties. The difference energy calculated between the magnetic configurations confirms that the ground state antiferromagnetic (AFM) is more stable than the paramagnetic (PM) states. The total magnetization, susceptibility, specific heat and magnetic entropy and relative cooling power of this compound are studied. The maximum value of the magnetic entropy was obtained near the paramagnetic AFM- PM transition for (WC-GGA, GGA) and GGA + U equal to 38.31 J.kg−1.K−1 and 16.72 J.kg−1.K−1 respectively.
Cosmological solution through gravitational decoupling in Brans-Dicke gravity
Authors: Sharif M , Majid Amal
Published: January 2021

In this paper, we compute an anisotropic cosmological solution through a minimal geometric deformation on a non-static spherical spacetime in the framework of self-interacting Brans-Dicke theory. The transformation of the radial component decouples the field equations into two arrays such that the influence of the anisotropic source is limited to one set only. We use FLRW universe model to obtain a solution of the system governed by the isotropic matter source. For this purpose, power-law models of the scale factor as well as massive scalar field are assumed while isotropic pressure and density are related via barotropic equation of state. The decoupling function, appearing in the other set, is evaluated through the conservation equation of the anisotropic source. Finally, we investigate the physical behavior, viability and stability of the extended FLRW solution for different values of the equation of state parameter. It is concluded that the solution is viable and stable for the massless scalar field and the radiation dominated universe.
Control of self-sustained oscillatory behavior in the dynamics of generalized Bonhoeffer-van der Pol system: Effect of asymmetric parameter
Authors: SONNA Armel Viquit , YEMELE David
Published: January 2021

A generalized form of the autonomous Bonhoeffer-van der Pol (BVdP) system described by a second-order dynamical system with six independent parameters consistent with its optimal mathematical modeling, instead of three usually used, is investigated. Through its equivalent form, the generalized asymmetric van der Pol-Duffing (GAVdPD) system and the steady states of this system are derived. The analysis show that the system may exhibit one or three steady states when it is driven by an external constant impulse taken as a main control parameter. Domain ranges in which the system can function as well as monostable system as a bistable system are derived. In addition, by means of the theory of Hopf Bifurcation, it appears that there are large possibilities for the system to work as self-sustained oscillator, forced oscillator or other possibilities for which the system does not operate, indicating the richness of this generalized form of the BVdP system. Limit cycle solutions are derived at the neighboring of the Andronov-Hopf Bifurcation points even for large values of the asymmetric parameter. All these results are checked through numerical simulations. Applying these analytical investigations to the electronic circuit executing the dynamics of the basic BVdP system, two distinct working regimes are highlighted, depending on the magnitude of the capacitance with respect to a threshold value function of the characteristic parameters both of the self and of the nonlinear resistance. Through PSPICE simulations the accuracy of these analytical and numerical investigations have been confirmed.
Quasi-periodic Oscillation of Blazar PKS 1424–418 in γ-Ray Band
Authors: Yang Jianping , Cao Gang , Zhou Bing , Qin Longhua
Published: January 2021

We perform the quasi-periodic oscillation (QPO) analysis of blazar PKS 1424−418 in the γ-ray (0.1–300 GeV) band from 2009 May 12 to 2019 September 17 (MJD 54963−58743). Using the spectral domain methods, Bhatta & Dhital reported that this source has 353 days periodic flux oscillations in the γ-ray flux. Adopting time domain methods, we confirm the previous detection that a possible γ-ray QPO of ∼355 days with the high significance level. Combining two methods of time domain and spectral domain provides stronger evidence for the existence of the QPO. Especially, after the strongest flare, γ-ray light-curve exhibits stronger periodic significance compared with the whole observation period. Assuming that the QPO is come from the orbital motion in a supermassive binary black hole system, the mass of primary black hole for this source is estimate as M ∼ 3.5 × 108–5.5 × 109
M
⊙.
Production of super-heavy nuclei in cold fusion reactions
Authors: Denisov V. Yu. , Sedykh I. Yu.
Published: January 2021

A model for cold-fusion reactions related to the synthesis of super-heavy nuclei in collisions of heavy projectile-nuclei with a 208Pb target nucleus is discussed. In the framework of this model, the production of the compound nucleus by two paths, the di-nuclear system path and the fusion path, are taken into account simultaneously. The formation of the compound nucleus in the framework of the di-nuclear system is related to the transfer of nucleons from the light nucleus to the heavy one. The fusion path is linked to the sequential evolution of the nuclear shape from the system of contacting nuclei to the compound nucleus. It is shown that the compound nucleus is mainly formed by the fusion path in cold-fusion reactions. The landscape of the potential energy related to the fusion path is discussed in detail. This landscape for very heavy nucleus-nucleus systems has an intermediate state, which is linked to the formation of both the compound nucleus and the quasi-fission fragments. The decay of the intermediate state is taken into account in the calculation of the compound nucleus production cross sections and the quasi-fission cross sections. The values of the cold-fusion cross sections obtained in the model agree well with the experimental data.
Review of field characterization techniques for high intensity therapeutic ultrasound
Authors: Xing Guangzhen , Wilkens Volker , Yang Ping
Published: January 2021

High-intensity therapeutic ultrasound (HITU) is a minimally invasive and non-ionizing medical procedure used to combat cancers. Faithful characterization of HITU fields is fundamental to ensure patient safety and clinical efficiency. However, standardized quality assurance protocols have not yet been established for HITU, which is a prerequisite for the wide acceptance of HITU as a therapeutic modality. This review discusses the challenges in the acoustic output characterization of HITU and the solutions that have been proposed to overcome this issue. The purpose of this review is to discuss the state of art of the metrological techniques, and invoke new ideas to prompt further development of HITU usage and characterization techniques, to ensure the safe and effective usage of therapeutic ultrasound.
Outer midplane neutral density measurements and H-mode fueling studies in NSTX-U
Authors: Scotti F. , Stotler D.P. , Bell R.E. , LeBlanc B.P. , Sabbagh S.A. , Soukhanovskii V.A. , Umansky M.V. , Zweben S.J.
Published: January 2021

Neutral density profiles are measured on the outboard midplane of the National Spherical Torus Experiment Upgrade (NSTX-U) using a two dimensional camera (ENDD, edge neutral density diagnostic) filtered for deuterium Balmer α (D
α
) emission interpreted via simulations using the Monte Carlo neutral transport code DEGAS 2. Deuterium atomic densities n
D are calculated by inverting the line-integrated D
α
brightness and using local measurements of electron density n
e and temperature T
e to determine atomic rate coefficients. The assumptions used in the derivation of n
D from D
α
emissivity are validated using DEGAS 2 to estimate contributions to emissivity due to electron impact excitation and molecular processes. Experimental measurements and DEGAS 2 simulations are compared over a database of L- and H-mode discharges, showing good agreement in D
α
emissivity profiles. Residual disagreement between experiment and simulations is suggestive of the possible role of intermittent transport and uncertainties in the molecular data. DEGAS 2 simulations are further used to complement the ENDD diagnostic, extracting neutral (atomic and molecular) densities at locations where the ENDD measurement are not made or where the assumptions used in the ENDD analysis are not valid. Deuterium atomic densities and ionization profiles on the outer midplane are compared for L-mode and H-mode discharges in NSTX-U. One-way coupling of DEGAS 2 to UEDGE multi-fluid simulations constrained by experimental data is used to study edge fueling and neutral penetration in NSTX-U discharges.
Optimizing beam-ion confinement in ITER by adjusting the toroidal phase of the 3D magnetic fields applied for ELM control
Authors: Sanchis L. , Garcia-Munoz M. , Viezzer E. , Loarte A. , Li L. , Liu Y.Q. , Snicker A. , Chen L. , Zonca F. , Pinches S.D. , Zarzoso D.
Published: January 2021

The confinement of neutral beam injection (NBI) particles in the presence of n = 3 resonant magnetic perturbations (RMPs) in 15 MA ITER DT plasmas has been studied using full orbit ASCOT simulations. Realistic NBI distribution functions, and 3D wall and equilibria, including the plasma response to the externally applied 3D fields calculated with MARS-F, have been employed. The observed total fast-ion losses depend on the poloidal spectra of the applied n = 3 RMP as well as on the absolute toroidal phase of the applied perturbation with respect to the NBI birth distribution. The absolute toroidal phase of the RMP perturbation does not affect the ELM control capabilities, which makes it a key parameter in the confinement optimization. The physics mechanisms underlying the observed fast-ion losses induced by the applied 3D fields have been studied in terms of the variation of the particle canonical angular momentum (δP

ϕ
) induced by the applied 3D fields. The presented simulations indicate that the transport is located in an edge resonant transport layer as observed previously in ASDEX upgrade studies. Similarly, our results indicate that an overlapping of several linear and nonlinear resonances at the edge of the plasma might be responsible for the observed fast-ion losses. The results presented here may help to optimize the RMP configuration with respect to the NBI confinement in future ITER discharges.
Analysis of the fusion performance, beam–target neutrons and synergistic effects of JET’s high-performance pulses
Authors: Kirov K.K. , Belonohy E. , Challis C.D. , Eriksson J. , Frigione D. , Garzotti L. , Giacomelli L. , Hobirk J. , Kappatou A. , Keeling D. , King D. , Lerche E. , Lomas P.J. , Nocente M. , Reux C. , Rimini F.G. , Sips A.C.C. , Van Eester D. , Contributors JET
Published: January 2021

Achieving high neutron yields in today’s fusion research relies on high-power auxiliary heating in order to attain required core temperatures. This is usually achieved by means of high neutral beam (NB) and radio frequency (RF) power. Application of NB power is accompanied by production of fast beam ions and associated beam–target (BT) reactions. In standard JET operational conditions, deuterium (D) NBs are injected into D plasmas. The injected beams comprise D atoms at full, one-half and one-third injected energy. Typically, the full energy of the injected D beams is between 90 and 120 keV, providing 1.4–2.0 MW of heating, which is about half of the injected power. Half-energy D beams carry about one-third of the injected power and the rest of the power is carried by the third energy fraction of D beams. Under these conditions, thermal fusion reactions, i.e. those between plasma ions, and BT reactions are of the same order of magnitude. This study addresses important issues regarding the impact of density, central electron and ion temperatures and their ratio, T
i(0)/T
e(0), on fusion performance, measured by the total neutron yield and BT neutron counts. NB/RF synergistic effects are discussed as well. It is demonstrated that thermal fusion gain increases linearly with normalised plasma pressure, β
N, and confinement, B
t
τ. The BT neutrons are, however, more difficult to predict and this task in general requires numerical treatment. In this study, BT neutrons in JET’s best-performing baseline and hybrid pulses are analysed and the underlying dependencies discussed. Central fast ion densities are found to decrease with increased density and density peaking. This is attributed to poorer beam penetration at high density. The BT reactions however are unchanged and can even increase if operating at higher core temperatures. An increase in the central ion temperature and T
i(0)/T
e(0) ratio leads to higher total and BT reaction rates whilst simultaneously the ratio of the BT to total neutron decreases significantly. NB/RF synergistic effects are found to have a negligible impact on total neutron rate. This can be explained by the reduced beam penetration in high-density conditions leading to lower central fast ion density.
Broadband generation of rational-order optical vortices using a bilateral meta-grating
Authors: Huang Kun , Liu Hong , Teng Jinghua
Published: January 2021

Optical vortices usually carry integer orbital angular momentum (OAM) of light. Recently, optical vortices with rational-order OAMs have also been created continuously for entangling the super-position OAM states of monochromatic light in a single device. Here, we report the broadband generation of such rational-order optical vortex beams by using a bilateral meta-grating. The meta-grating contains two oblique gratings that encode two sign-opposite linear phase profiles in two symmetric sides, thus leading to phase dislocation along the symmetric axis. We reveal that the encoded phase profiles are valid in a range of wavelengths due to the broadband response of the meta-grating. The measured phase, intensity and tilting angles match perfectly with theoretical prediction, suggesting the bilateral meta-grating as a powerful device to create broadband and continuous OAM of light for various applications such as optical micro-manipulation, optical communication, quantum physics, and super-resolution imaging.
Analytic treatment of nonparaxial full-Poincaré fields: singularity structure and trapping properties
Authors: Gutiérrez–Cuevas Rodrigo , Alonso Miguel A
Published: January 2021

An analytic extension to the nonparaxial regime of the full-Poincaré (FP) beams is presented. Instead of the stereographic mapping used in the paraxial case, these FP fields are defined in terms of a mapping from the polarization Poincaré sphere onto the sphere of plane-wave directions. It is shown that multipolar fields with complex arguments can be used to implement this mapping and provide closed-form expressions. The three-dimensional polarization singularities of the resulting fields are studied with the help of auxiliary fields presenting vortices at points where the polarization is circular or linear. Finally, the Mie scattering and trapping properties of the FP fields are studied, both of which are greatly simplified by the choice of fields.
Physical mechanism of layer-dependent strong and weak coupling with electromagnetic wave in 2H-MoS2
Authors: Liang Lin , Song Jizhe , Han Mengtong , Ding Yong , Li Qiu , Wang Jingang
Published: January 2021

In this work, we use the first-principles calculation method to theoretically study the strong and weak coupling between the layer-dependent MoS2 and electromagnetic waves. Through the calculation of the electronic structure and the analysis and fitting of Van Hove singularity (VHS), the differences between the strong coupling and weak coupling mechanisms are discussed. The exponential law of electronic structure parameters with the number of layers is explained. Finally, combined with cavity quantum electrodynamics (QED), it is revealed that the physical mechanism of strong coupling and weak coupling is related to the transition dipole moment. Strong coupling is dominated by inter-band transitions and weak coupling is dominated by in-band transitions.
Preliminary study of an open-air water-contacting discharge for direct nitrogen fixation
Authors: SHU Zhan , WANG Chuanqi , HOSSAIN Insaf , CHEN Qiang , LI Wanlian , WANG Jinqi , LIU Pengfei , XIONG Qing
Published: January 2021

Efficient nitrogen fixation through a reactive plasma process attracts intense interest due to the environmental issues induced by the conventional Haber–Bosch method. In this work, we present a direct and simple fixation routine without any catalysts for nitrogen in open air using an atmospheric-pressure pin-to-solution plasma electrolytic system. Nitrate, nitrite, and ammonia as the nitrogen-derived chemicals in solution were analyzed as indicators under various discharge conditions to estimate the energy efficiency of this process. The results show that the nitrogen fixation process was much more efficient by the pin-positive discharge compared to the negative one. N chemicals preferred to be formed when the solution was of negative polarity. It was also found that, with the help of solution circulation, the energy efficiency was enhanced compared to that of static liquid. However, an inverse trend was observed with the increase of the discharge current. Further study by optical emission spectroscopy indicates the important roles of active

N

2

*

and water vapour and their derived species near the plasma–water interface in the fixation process.
Nonlinear evolution and secondary island formation of the double tearing mode in a hybrid simulation
Authors: MAO Aohua , WANG Zhibin , HE Xianglei , WANG Xiaogang
Published: January 2021

Double tearing modes (DTMs), induced by double current sheet configurations or two neighboring rational surfaces with the same safety factor in tokamaks, are widely observed in solar, space, and fusion plasmas. In this paper, the evolution of DTMs without a guide field is investigated numerically using a hybrid model (electron fluid + ion PIC). The overall evolution processes of DTMs are qualitatively consistent with previous works using other models. The particle dynamics during the evolution of DTMs is analyzed in detail. Behaviors of ions and electrons present different characteristics around the reconnection region which gives rise to Hall effects producing the out-of-plane quadrupole magnetic field. In the explosive reconnection process with interactions between two DTMs islands, the asymmetric drive and the thin current layer feature lead to the emergence of secondary magnetic islands which develop with the late evolution of the DTMs.
Towards understanding the brittle–ductile transition in the extreme manufacturing
Authors: Zhang Tao , Jiang Feng , Huang Hui , Lu Jing , Wu Yueqin , Jiang Zhengyi , Xu Xipeng
Published: January 2021

The brittle–ductile transition (BDT) widely exists in the manufacturing with extremely small deformation scale, thermally assisted machining, and high-speed machining. This paper reviews the BDT in extreme manufacturing. The factors affecting the BDT in extreme manufacturing are analyzed, including the deformation scale and deformation temperature induced brittle-to-ductile transition, and the reverse transition induced by grain size and strain rate. A discussion is arranged to explore the mechanisms of BDT and how to improve the machinability based on the BDT. It is proposed that the mutual transition between brittleness and ductility results from the competition between the occurrence of plastic deformation and the propagation of cracks. The brittleness or ductility of machined material should benefit a specific manufacturing process, which can be regulated by the deformation scale, deformation temperature and machining speed.
On the Use of Regression Calibration in a Complex Sampling Design With Application to the Hispanic Community Health Study/Study of Latinos
Authors: Baldoni Pedro L , Sotres-Alvarez Daniela , Lumley Thomas , Shaw Pamela A
Published: January 2021

Regression calibration is the most widely used method to adjust regression parameter estimates for covariate measurement error. Yet its application in the context of a complex sampling design, for which the common bootstrap variance estimator can be less straightforward, has been less studied. We propose 2 variance estimators for a multistage probability-based sampling design, a parametric and a resampling-based multiple imputation approach, where a latent mean exposure needed for regression calibration is the target of imputation. This work was motivated by the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) data from 2008 to 2011, for which relationships between several outcomes and diet, an error-prone self-reported exposure, are of interest. We assessed the relative performance of these variance estimation strategies in an extensive simulation study built on the HCHS/SOL data. We further illustrate the proposed estimators with an analysis of the cross-sectional association of dietary sodium intake with hypertension-related outcomes in a subsample of the HCHS/SOL cohort. We have provided guidelines for the application of regression models with regression-calibrated exposures. Practical considerations for implementation of these 2 variance estimators in the setting of a large multicenter study are also discussed. Code to replicate the presented results is available online.
Assessment of Conflicts of Interest in Studies of Breast Implants and Breast Implant Mesh
Authors: Tian Tina , Sekigami Yurie , Char Sydney , Bloomenthal Molly , Aalberg Jeffrey , Chen Lilian , Chatterjee Abhishek
Published: January 2021

Background

With increased collaboration between surgeons and industry, there has been a push towards improving transparency of conflicts of interest (COI).

Methods

A literature search identified all articles published between 2016 – 2018 involving breast implants/implantable mesh from three major United States plastic surgery journals. Industry payment data from 8 breast implant/implantable mesh companies was collected using the CMS Open Payments database. COI discrepancies were identified by comparing author declaration statements with payments >$100.00 found for the year of publication and year prior. Risk factors for discrepancy were determined at study and author levels.

Results

A total of 162 studies (548 authors) were identified. 126 (78%) studies had at least one author receive undisclosed payments. 295 (54%) authors received undisclosed payments. Comparative studies were significantly more likely to have COI discrepancy than non- comparative studies (83% vs 69%, p < 0.05). Multivariate analysis showed no association between COI discrepancy and final product recommendation. Authors who accurately disclosed payments received higher payments compared to authors who did not accurately disclose payments (median $40,349 IQR 7278-190,413 vs median $1300 IQR 429-11,1544, p <0.001).

Conclusions

The majority of breast implant-based studies had undisclosed COIs. Comparative studies were more likely to have COI discrepancy. Authors who accurately disclosed COIs received higher payments than authors with discrepancies. This study highlights the need for increased efforts to improve the transparency of industry sponsorship for breast implant-based studies.
Aerobic bioconversion of C-glycoside mangiferin into its aglycone norathyriol by an isolated mouse intestinal bacterium
Authors: Hasanah Uswatun , Miki Kasumi , Nitoda Teruhiko , Kanzaki Hiroshi
Published: January 2021

Norathyriol is an aglycone of a xanthonoid C-glycoside mangiferin that possesses different bioactive properties useful for humans compared to mangiferin. Mangiferin is more readily available in nature than norathyriol; thus, efficient mangiferin conversion into norathyriol is desirable. There are a few reports regarding mangiferin C-deglycosylation because of the C–C bond resistance toward acid, alkaline, and enzyme hydrolysis. In this study, we isolated a mangiferin-deglycosylating bacterium strain KM7-1 from the mouse intestine. 16S rDNA sequencing indicated that KM7-1 belongs to the Bacillus genus. Compared to the taxonomically similar bacteria, the growth characteristic of facultative anaerobic and thermophilic resembled, yet only Bacillus sp. KM7-1 was able to convert mangiferin into norathyriol. Resting cells of Bacillus sp. KM7-1 obtained from aerobic cultivation at 50 °C showed high norathyriol formation from 1 m m of mangiferin. Norathyriol formation can be conducted either under aerobic or anaerobic conditions, and the reaction depended on time and bacterial amount.
From mutation to mechanism: deciphering the molecular function of genetic variants linked to human ageing
Authors: Baghdadi Maarouf , Hinterding Helena M , Partridge Linda , Deelen Joris
Published: January 2021

Many of the leading causes of death in humans, such as cardiovascular disease, type 2 diabetes and Alzheimer’s disease are influenced by biological mechanisms that become dysregulated with increasing age. Hence, by targeting these ageing-related mechanisms, we may be able to improve health in old age. Ageing is partly heritable and genetic studies have been moderately successful in identifying genetic variants associated with ageing-related phenotypes (lifespan, healthspan and longevity). To decipher the mechanisms by which the identified variants influence ageing, studies that focus on their functional validation are vital. In this perspective, we describe the steps that could be taken in the process of functional validation: (1) in silico characterisation using bioinformatic tools; (2) in vitro characterisation using cell lines or organoids; and (3) in vivo characterisation studies using model organisms. For the in vivo characterisation, it is important to focus on translational phenotypes that are indicative of both healthspan and lifespan, such as the frailty index, to inform subsequent intervention studies. The depth of functional validation of a genetic variant depends on its location in the genome and conservation in model organisms. Moreover, some variants may prove to be hard to characterise due to context-dependent effects related to the experimental environment or genetic background. Future efforts to functionally characterise the (newly) identified genetic variants should shed light on the mechanisms underlying ageing and will help in the design of targeted interventions to improve health in old age.
Network-adjusted Kendall’s Tau Measure for Feature Screening with Application to High-dimensional Survival Genomic Data
Authors: Wang Jie-Huei , Chen Yi-Hau
Published: January 2021

Motivation

In high-dimensional genetic/genomic data, the identification of genes related to clinical survival trait is a challenging and important issue. In particular, right-censored survival outcomes and contaminated biomarker data make the relevant feature screening difficult. Several independence screening methods have been developed, but they fail to account for gene–gene dependency information, and may be sensitive to outlying feature data.

Results

We improve the inverse probability-of-censoring weighted (IPCW) Kendall’s tau statistic by using Google’s PageRank Markov matrix to incorporate feature dependency network information. Also, to tackle outlying feature data, the nonparanormal approach transforming the feature data to multivariate normal variates are utilized in the graphical lasso procedure to estimate the network structure in feature data. Simulation studies under various scenarios show that the proposed network-adjusted weighted Kendall’s tau approach leads to more accurate feature selection and survival prediction than the methods without accounting for feature dependency network information and outlying feature data. The applications on the clinical survival outcome data of diffuse large B-cell lymphoma and of The Cancer Genome Atlas lung adenocarcinoma patients demonstrate clearly the advantages of the new proposal over the alternative methods.

Supplementary information

Supplementary data are available at Bioinformatics online.
Extraordinary diversification of the “bristle flies” (Diptera: Tachinidae) and its underlying causes
Authors: Stireman John O , Cerretti Pierfilippo , O’hara James E , Moulton John K
Published: January 2021

The family Tachinidae (“bristle flies”) is the most diverse and ecologically important group of insect parasitoids outside the parasitic wasps. It is among the most species rich families of flies (Diptera) and has experienced a recent adaptive radiation across the globe. We make use of a molecular phylogeny of the family to examine its rapid radiation and explore the traits of tachinid lineages that may have contributed to variation in their diversification. We apply a range of diversification analyses to assess the consistency and robustness of effects. We find that the Tachinidae are among the most rapidly diversifying families of animals. Six to eight clades of bristle flies, distributed across the phylogeny, exhibit strong evidence of accelerated diversification. Our results suggest that the use of holometabolous insect larvae, and specifically caterpillars (Lepidoptera), as hosts, is associated with increased diversification rates. However, these effects were inconsistent across analyses. We detected little influence of oviposition strategy (egg type) or host feeding habit, and we recovered evidence that unmeasured “hidden” traits may explain greater variance in diversification. We evaluated the strengths and weaknesses of different Maximum Likelihood and Bayesian approaches for analysing diversification and the potential for extrinsic factors, such as geography, to influence patterns of richness and diversification. In general, we conclude that although certain traits may provide opportunities for diversification, whether this is capitalized on may depend on additional traits and/or historical contingency.
Capillary Electrophoresis Separation of Artepillin C: Determination in Brazilian Green Propolis
Authors: Galeotti Fabio , Capitani Federica , Maccari Francesca , Mantovani Veronica , Volpi Nicola
Published: January 2021

Propolis is important in complementary and alternative medicine having well-known therapeutic applications. Artepillin C, a main component of Brazilian (green) propolis, has attracted great attention for its anticancer action. Consequently, the synthesis of artepillin C has been reported but, due to the limited yield and elevated costs, this biomolecule is largely produced from Brazilian propolis. We report the capillary electrophoresis (CE) separation of artepillin C in Brazilian propolis also comparing the results with those of HPLC-UV-MS. Optimal separation was obtained with a simple buffer constituted of sodium tetraborate 30 mM pH 9.2 and detection at 210 nm. Artepillin C and the polyphenols of propolis were fully separated with a voltage gradient of 30 to 8 kV and a current of 300 μA for a total run of 50 min. The sensitivity of CE-UV was 22 times greater than HPLC-UV and 100 times more than HPLC-MS with also a stronger reduction in the run time and a greater robustness and reproducibility. The development of CE as an effective and reliable method for the analysis of artepillin C is desired as the standardized quality controls are essential before propolis or its biomolecules can be adopted routinely in nutraceuticals, food ingredients and therapeutic applications.
Simultaneous Estimation of Apremilast and Betamethasone Dipropionate in Microsponge-Based Topical Formulation using a Stability Indicating RP-HPLC Method: A Quality-by-Design Approach
Authors: Mullick Prashansha , Mutalik Sadhana P , Hegde Aswathi R , Pandey Abhijeet , Jagadish P C , Kini Suvarna G , Jain Sanyog , Mutalik Srinivas
Published: January 2021

A stability-indicating reverse phase high-performance liquid chromatography method was developed and validated for simultaneous quantification of apremilast (APL) and betamethasone dipropionate (BD) in bulk as well as drug loaded microsponges. Various mobile phase systems were screened to check the system suitability followed by force degradation analysis to determine APL and BD stability under varying stress conditions. A central composite design model was used to optimize the column temperature and flow rate using Design Expert® (9.0.1). One factor at a time approach with five independent factors were used to validate the robustness of the method. Finally, APL and BD were precisely and accurately quantified from drug loaded microsponges using the validated method. A favorable separation of APL and BD was obtained on a Phenomenex® Luna C18 column using a mixture of 50 mM phosphate buffer containing 0.1% triethylamine (pH 6.1) and acetonitrile (60:40%v/v) as mobile phase. Both the drugs were found to be stable when exposed to stressors such as heat-, light-, alkali-, acid- and peroxide-induced degradation. The calibration curves were found to be linear with appreciable limit of detection and limit of quantification. Recovery and percentage relative standard deviation of peak areas for APL and BD were found to be < 2.0% and 99–100% in bulk drug solution and <2.0% and 99–103% in microsponge formulation, respectively. Statistical analysis using analysis of variance indicated that the model was significant (P < 0.001). Hence, the developed method can be effectively used to quantify APL and BD, both in bulk as well as microsponge formulations.