bluuebunny/crossref_metadata_2025 huggingface dataset:
Neonatal Intestinal Segmental Volvulus: What Are the Differences with Midgut Volvulus?
Authors: Casalino Maria , Miscia Maria Enrica , Lauriti Giuseppe , Gauda Estelle , Zani Augusto , Zani-Ruttenstock Elke
Published: August 2023

Objective Intestinal volvulus in the neonate is a surgical emergency caused by either midgut volvulus (MV) with intestinal malrotation or less commonly, by segmental volvulus (SV) without intestinal malrotation. The aim of our study was to investigate if MV and SV can be differentiated by clinical course, intraoperative findings, and postoperative outcomes.

Methods Using a defined search strategy, two investigators independently identified all studies comparing MV and SV in neonates. PRISMA guidelines were followed, and a meta-analysis was performed using RevMan 5.3.

Results Of 1,026 abstracts screened, 104 full-text articles were analyzed, and 3 comparative studies were selected (112 patients). There were no differences in gestational age (37 vs. 36 weeks), birth weight (2,989 vs. 2,712 g), and age at presentation (6.9 vs. 3.8 days). SV was more commonly associated with abnormal findings on fetal ultrasound (US; 65 vs. 11.6%; p < 0.00001). Preoperatively, SV was more commonly associated with abdominal distension (32 vs. 77%; p < 0.05), whereas MV with a whirlpool sign on ultrasound (57 vs. 3%; p < 0.01). Bilious vomiting had similar incidence in both (88 ± 4% vs. 50 ± 5%). Intraoperatively, SV had a higher incidence of intestinal atresia (2 vs. 19%; p < 0.05) and need for bowel resection (13 vs. 91%; p < 0.00001). There were no differences in postoperative complications (13% MV vs. 14% SV), short bowel syndrome (15% MV vs. 0% SV; data available only from one study), and mortality (12% MV vs. 2% SV).

Conclusion Our study highlights the paucity of studies on SV in neonates. Nonetheless, our meta-analysis clearly indicates that SV is an entity on its own with distinct clinical features and intraoperative findings that are different from MV. SV should be considered as one of the differential diagnoses in all term and preterm babies with bilious vomiting after MV was ruled out—especially if abnormal fetal US and abdominal distension is present.
Valuation method of intellectual property pledge financing based on income interval analysis and risk adjustment coefficient
Authors: Su Rengang , Li Ming , Fang YinHai , Yang Chonghuai
Published: August 2023

This study has developed a new method to valuate intellectual property for pledge financing. First, based on interval theory and the relevant calculation rules, the income interval model is and then used to calculate the interval values of intellectual property. Second, based on the change structure of risk indicators, the AHP and set-valued statistics are utilized to calculate the risk adjustment coefficient. Third, the point value of intellectual property is calculated with its values at an interval scale and risk adjustment coefficient. The values of intellectual property at an interval scale provide the two parties negotiating pledge financing with a reference range of loan amounts. The risk adjustment coefficient becomes a crucial indicator for measuring value evaluation risk. The point value of intellectual property specifies how much the bank loan amount can deviate from the values of intellectual property at an interval scale. The method creates a multi-indicator system to valuate intellectual property for pledge financing, which lowers the risk of intellectual property pledge financing to a significant extent and facilitates its operation. Moreover, the method has been proven to be efficient in practice.
Coalescence-induced jumping of bubbles in shear flow in microgravity
Authors: Raza Md. Qaisar , Köckritz Moritz von , Sebilleau Julien , Colin Catherine , Zupancic Matevz , Bucci Mattia , Troha Tadej , Golobic Iztok
Published: August 2023

Bubble removal from a solid surface is of significant importance to many technical processes and applications. In addition to the conventional buoyancy-aided bubble removal, there is also a passive strategy to remove bubbles from a solid surface via coalescence. However, likewise several processes, the coalescence-induced removal of bubbles from the solid surface is masked by the dominant buoyancy, hence, difficult to observe in terrestrial conditions. Microgravity condition offers a unique opportunity to investigate such phenomenon in great detail that can significantly improve our fundamental understanding. In this work, we report coalescence-induced jumping of isolated vapor bubbles from the heated substrate during shear flow in microgravity condition. We show that, similar to the coalescence-induced jumping droplets, when two bubbles coalesce, the resulting big coalesced bubble jumps from the substrate due to the conversion of excess surface energy into the translational kinetic energy, which provides the requisite initial velocity for jumping. Jumping of bubbles over a wide range of bubble size (post-coalescence radius ≈0.9–3.4 mm) is observed. Bubbles oscillate continuously while rising through certain height post-coalescence. We perform force balance and scaling analysis to develop a model to predict the maximum jumping height of bubbles. We show that the jumping height is strongly related to the bubble size and the non-dimensional Ohnesorge number, which captures the role of fluid properties governing the coalescence. The physical insight presented in this work has implication for the design of energy systems and microfluidic devices for the earth and space-based applications.
Enhancing performance of blue ZnTeSe-based quantum dot light-emitting diodes through dual dipole layers engineering
Authors: Li Qiuyan , Cao Sheng , Bi Yuhe , Yu Peng , Xing Ke , Song Yusheng , Du Zhentao , Zou Bingsuo , Zhao Jialong
Published: August 2023

Blue ZnTeSe-based quantum dot light-emitting diodes (QLEDs) often suffer from poor hole injection, which significantly limits their performance. Herein, we introduced dual dipole layers consisting of (2, 3, 6, 7, 10, 11 hexaazatriphenyl hexacarbonitrile) (HAT-CN) between the hole injection layer of poly (3,4-ethylenedioxythiophene): poly (styrene sulfonate) (PEDOT: PSS) and hole transport layer of (polyvinylcarbazole) (PVK) to enhance the performance of blue ZnTeSe-based QLEDs. The introduction of the HAT-CN layer created dual dipole layers, which reduce the hole injection barrier between PEDOT: PSS and PVK, decrease the hole defect density, increase the hole current, and improve the effective radiation recombination of charge carriers. The QLEDs with the HAT-CN layer exhibited higher external quantum efficiency compared to those without the HAT-CN layer, increasing from 4.2% to 10.1%. Moreover, the T50 lifetime almost doubled at a high luminance of 2000 cd m−2. This work shows that introducing the HAT-CN layer to create dual dipole layers using the full solution method is an effective strategy for preparing high-performance ZnTeSe-based blue QLEDs.
Obliquely propagating nonlinear magnetosonic waves in non-Maxwellian plasmas
Authors: Izhar Navaira , Qureshi M. N. S. , Shah H. A.
Published: August 2023

In this paper, propagation characteristics of obliquely propagating nonlinear magnetosonic waves in hot nonthermal plasmas have been studied. The expressions of modified temperatures have been derived for non-Maxwellian Q-nonextensive and (r, q) distributions and then incorporated into the one-fluid magnetohydrodynamic model. By employing the reductive perturbation technique, we derived the linear dispersion relation (LDR) and nonlinear Kadomstev–Petvashvilli (KP) equation for slow and fast magnetosonic wave modes in two dimensions. We then investigated the LDR and nonlinear propagation of KP solitons for both the slow and fast mode magnetosonic waves and found that propagation characteristics are significantly altered by considering the effect of modified temperature. The results presented here would depict a realistic picture of the propagation of nonlinear magnetosonic waves in non-Maxwellian plasmas.
Fluid shear stress enhances natural killer cell's cytotoxicity toward circulating tumor cells through NKG2D-mediated mechanosensing
Authors: Hu Bing , Xin Ying , Hu Guanshuo , Li Keming , Tan Youhua
Published: August 2023

Tumor cells metastasize to distant organs mainly via hematogenous dissemination, in which circulating tumor cells (CTCs) are relatively vulnerable, and eliminating these cells has great potential to prevent metastasis. In vasculature, natural killer (NK) cells are the major effector lymphocytes for efficient killing of CTCs under fluid shear stress (FSS), which is an important mechanical cue in tumor metastasis. However, the influence of FSS on the cytotoxicity of NK cells against CTCs remains elusive. We report that the death rate of CTCs under both NK cells and FSS is much higher than the combined death induced by either NK cells or FSS, suggesting that FSS may enhance NK cell's cytotoxicity. This death increment is elicited by shear-induced NK activation and granzyme B entry into target cells rather than the death ligand TRAIL or secreted cytokines TNF-α and IFN-γ. When NK cells form conjugates with CTCs or adhere to MICA-coated substrates, NK cell activating receptor NKG2D can directly sense FSS to induce NK activation and degranulation. These findings reveal the promotive effect of FSS on NK cell's cytotoxicity toward CTCs, thus providing new insight into immune surveillance of CTCs within circulation.
Suppressing stimulated Raman side-scattering with vector light
Authors: Jia Xiaobao , Jia Qing , Yan Rui , Zheng Jian
Published: August 2023

Recent observations of stimulated Raman side-scattering (SRSS) in different laser inertial confinement fusion ignition schemes have revealed that there is an underlying risk of SRSS on ignition. In this paper, we propose a method that uses the nonuniform nature of the polarization of vector light to suppress SRSS, and we give an additional threshold condition determined by the parameters of the vector light. For SRSS at 90°, where the scattered electromagnetic wave travels perpendicular to the density profile, the variation in polarization of the pump will change the wave vector of the scattered light, thereby reducing the growth length and preventing the scattered electromagnetic wave from growing. This suppression scheme is verified through three-dimensional particle-in-cell simulations. Our illustrative simulation results demonstrate that for linearly polarized Gaussian light, there is a strong SRSS signal in the 90° direction, whereas for vector light, there is very little SRSS signal, even when the conditions significantly exceed the threshold for SRSS. We also discuss the impact of vector light on stimulated Raman backscattering, collective stimulated Brillouin scattering and two-plasmon decay.
Enhancing heat exchanger performance through hybrid angle of attack control for drop-shaped tubes
Authors: Deeb Rawad
Published: August 2023

In this study, a numerical investigation was conducted to explore the potential improvement in the overall performance of heat exchangers comprising drop-shaped tubes through the control of the angle of attack. A comprehensive analysis was conducted, evaluating eight distinct configurations of 20-row bundles consisting of drop-shaped tubes in both staggered and in-line arrangements. A thorough comparison was made against corresponding bundles with circular tubes. The study covered a range of Reynolds numbers Re = 1.78 × 103–1.87 × 104 and angles of attack θi−j = 0°–360°. Two methods were employed to evaluate the thermal-hydraulic performance. The findings indicated that the friction factor of case 6 of drop-shaped tube bundle (θ1−5 = 0°, θ6−10 = 330°, θ11−15 = 30°, θ16−20 = 0°) exhibited a reduction of approximately 27%–43% and 42%–46% compared to the staggered (case 3) and in-line (case 1) configurations of drop-shaped tube bundles at zero angles of attack, respectively. Additionally, case 6 achieved the highest thermal-hydraulic performance, surpassing the staggered bundles of circular tubes (case 3) by 1.4–1.8 times and the in-line bundles of circular tubes (case 1) by 2.9–3.5 times. Novel equations were derived to estimate the mean Nusselt number, effectiveness, and friction factor for case 6, exhibiting a maximum deviation of 0.74%, 0.48%, and 0.73% correspondingly.
Stochastic determination of thermal reaction rate coefficients for air plasmas
Authors: del Val Anabel , Chazot Olivier
Published: August 2023

This work deals with the stochastic inference of gas-phase chemical reaction rates in high temperature air flows from plasma wind tunnel experimental data. First, a Bayesian approach is developed to include not only measurements but also additional information related to how the experiment is performed. To cope with the resulting computationally demanding likelihood, we use the Morris screening method to find the reactions that influence the solution to the stochastic inverse problem from a mechanism comprising 21 different reactions for an air mixture with seven species: O2, N2, NO, NO+, O, N, e−. A set of six reactions, mainly involving nitrogen dissociation and exchange, are the ones identified to impact the solution the most. As such, they are assumed to be uncertain and estimated along with the boundary conditions of the experiment and the catalytic recombination parameters of the materials involved in the testing. The remaining 15 reactions are set to their nominal values. The posterior distribution is then propagated through the proposed boundary layer model to produce the posterior predictive distributions of the temperature and mass fraction profiles along the boundary layer stagnation line. It is identified that NO concentrations have the largest increase in uncertainty levels compared to cases where the inference problem is carried out for fixed chemical model parameter values. This allows us to inform a new experimental campaign targeting the reduction of uncertainties affecting the chemical models.
Direct sampling method to inverse wave-number-dependent source problems: determination of the support of a stationary source
Authors: Guo Hongxia , Hu Guanghui , Zhao Mengjie
Published: August 2023

This paper is concerned with a direct sampling method for imaging the support of a frequency-dependent source term embedded in a homogeneous and isotropic medium. The source term is given by the Fourier transform of a time-dependent source whose radiating period in the time domain is known. The time-dependent source is supposed to be stationary in the sense that its compact support does not vary along the time variable. Via a multi-frequency direct sampling method, we show that the smallest strip containing the source support and perpendicular to the observation direction can be recovered from far-field patterns at a fixed observation angle. With multiple but discrete observation directions, the shape of the so-called Θ-convex hull of the source support can be recovered. We even extend the proposed algorithm to the case of near-field data in three dimensions. The frequency-domain analysis performed here can be used to handle inverse time-dependent source problems. Our algorithm has low computational overhead and is robust against noise. Numerical experiments in both two and three dimensions have proved our theoretical findings.
Iterative inversion of the tensor momentum x-ray transform
Authors: Denisiuk Aleksander
Published: August 2023

The momentum x-ray transform maps a symmetric tensor field f of order m in

R

n

to its integrals over lines at + b with the weight tk
,

k
=
0
,
…
,
m

. In this article we propose an iterative approach to the reconstruction problem. Namely, a new concept of partial momentum transforms is introduced. These transforms are intermediaries between the momentum and the component-wise x-ray transforms. Moreover, one can use a differential operator to construct a sequence of partial momentum transforms that starts with the momentum and finishes with the component-wise transform. The latter can be inverted with the standard component-wise backprojection. The proposed method was also applied to obtain an analog of the Plancherel formula as well as the stability estimates in the Sobolev spaces that are valid for any m.
Comparison of vacuum-immersed helicon thrusters terminated by upstream magnetic and physical walls
Authors: Takahashi Kazunori
Published: August 2023

Thrusts imparted by helicon thrusters terminated by a cusp magnetic field and a physical wall are compared in a laboratory experiment, where the configurations have source lengths of 26 cm and 17.5 cm, respectively. The thruster is typically operated at about 5 kW of radiofrequency power and argon gas is used as a propellant. The influence of the cusp magnetic field inside the source on the thrust is clearly observed for the long source length case, while it does not significantly affect the thrust for the short source length case. The results imply that the thrust enhancement by the cusp magnetic field is due to the geometrical isolation of the plasma from the physical wall, which reduces energy loss to the wall. Furthermore, it is observed that the high-potential plasma for the short source length case is indeed unstable due to microarcings, which occur with an interval time of about sub-second. It is shown that the occurrence of microarcings induces a temporal change in the plasma potential, while no drastic change in the electron temperature is observed.
Improved dielectric and mechanical properties of aramid fiber reinforced epoxy resin composites by polyethyleneimine grafting
Authors: Du Boxue , Xue Rundong , Kong Xiaoxiao , Chen Yun
Published: August 2023

In this paper, aramid fiber surface is modified by polyethylenimine (PEI) grafting with abundant -NH2 active groups after plasma surface activation treatment. Various aramid fiber reinforced epoxy resin composites (AFRC) are prepared. The effects of PEI grafting on the dielectric and mechanical properties of AFRC are studied. Obtained results show that PEI is successfully grafted onto aramid fiber surface as evidenced by x-ray photoelectron spectroscopy results, and effectively improves the interfacial properties between aramid fiber and epoxy resin. The dielectric properties, including DC conductivity, dielectric constant, and integration charge Q(t) of the composites are improved after optimized modification parameters, and the breakdown strength is increased by up to 23%. These are attributed to the decrease in interfacial polarization and the increase in interfacial bonding strength. Furthermore, the interfacial shear strength of AFRC is increased from 29.5 MPa to 63.7 MPa, which further verifies the improvement of interfacial performance. This paper provides a way to improve the dielectric and mechanical properties of AFRC, which is of great significance for its application in high voltage power equipment.
The cell-centered Finite-Volume self-consistent approach for heterostructures: 1D electron gas at the Si–SiO2 interface
Authors: Mosallanejad Vahid , Li Haiou , Cao Gong , Chiu Kuei-Lin , Dou Wenjie , Guo Guo-ping
Published: August 2023

Achieving self-consistent convergence with the conventional effective-mass approach at ultra-low temperatures (below 4.2 K) is a challenging task, which mostly lies in the discontinuities in material properties (e.g. effective-mass, electron affinity, dielectric constant). In this article, we develop a novel self-consistent approach based on cell-centered finite-volume discretization of the Sturm–Liouville form of the effective-mass Schrödinger equation and generalized Poisson’s equation (FV-SP). We apply this approach to simulate the one-dimensional electron gas formed at the Si–SiO2 interface via a top gate. We find excellent self-consistent convergence from high to extremely low (as low as 50 mK) temperatures. We further examine the solidity of FV-SP method by changing external variables such as the electrochemical potential and the accumulative top gate voltage. Our approach allows for counting electron–electron interactions. Our results demonstrate that FV-SP approach is a powerful tool to solve effective-mass Hamiltonians.
Structural phase transition driven dielectric and optical properties with reduction in band gap in Sr2+ modified BaTiO3 ceramics
Authors: Mallick Jyotirekha , Kumar Ajay , Das Tupan , Pradhan Lagen Kumar , Parida Prakash , Kar Manoranjan
Published: August 2023

Ferroelectric materials with crystal symmetry transition from single phase to multiphase coexistence exhibit anomalous photosensitive properties. The optical properties (optical band gap and photosensitive) found on non-centrosymmetric and centrosymmetric systems achieved research interest because of their interesting behavior. In this regard, the lead-free polycrystalline Ba1−x
Sr
x
TiO3 (BSTO, 0

⩽
x
⩽
0.3

) has been synthesized to explore its crystal structure, dielectric, light absorption, and photocurrent sensing properties for various applications. Both experimental and theoretical studies on BSTO (0

⩽
x
⩽
0.3
)

 

ceramics confirm the crystal symmetry transition with the reduction of band gap as compared to pristine BaTiO3. This crystal symmetry transition plays an important role in varying the various physical properties as it involves the transition from the polar phase to the non-polar phase. The optical band gap has been estimated experimentally by the Tauc plot method and found that there is a small variation of energy band gap from 3.615 eV to 3.212 eV with Sr substitution. The highest dielectric constant was found to be 5327 at lower frequency on Ba0.76Sr0.24TiO3 after that for further increase in Sr concentration the dielectric constant decreases because of the introduction of the non-polar phase. A strong correlation between crystal structure and physical properties (dielectric, optical, etc.) has been observed. The photocurrent of the samples is significant which reveals that the sample is influenced by the photons. In a nutshell, the present study deepens the understanding of the correlation between crystal structure and various physical properties of BSTO and, hence provides an idea of required design parameters to construct a ferroelectric system for better photosensitive nature suitable for device applications.
Integration of N, P-doped carbon quantum dots with hydrogel as a solid-phase fluorescent probe for adsorption and detection of Fe3+
Authors: Dong Guohua , Lv Qihang , Hao Lijuan , Zhang Wenzhi , Zhang Zhuanfang , Chai Dong-feng , Zhu Min , Zhao Ming , Li Jinlong
Published: August 2023

In this work, a novel nitrogen-phosphorus co-doped carbon quantum dots (N, P-CQDs) hydrogel was developed utilizing the as-synthesized N, P-CQDs and acrylamide (AM) with the existence of ammonium persulfate and N, N′-methylene bisacrylamide (N-MBA). In consistent with pure N, P-CQDs, the N, P-CQDs hydrogel also shows a dramatic fluorescence property with maximum emission wavelength of 440 nm, which can also be quenched after adsorbing iron ions (Fe3+). When the concentration of Fe3+ is 0–6 mmol l−1, a better linear relationship between Fe3+ concentration and the fluorescence intensities can be easily obtained. Additionally, the N, P-CQDs hydrogel exhibits better recyclability. This confirms that the N, P-CQDs hydrogel can be used for adsorbing and detecting Fe3+ in aqueous with on–off–on mode. The fluorescence quenching mainly involves three procedures including the adsorption of Fe3+ by hydrogel, integration of Fe3+ with N, P-CQDs and the transportation of conjugate electrons in N, P-CQDs to the vacant orbits of Fe3+ and the adsorption process follows a pseudo-second-order kinetic model confirmed in the Freundlich isotherm model. In conclusion, this work provides a novel route for synchronously removing and detecting the metal ions in aqueous by integrating N, P-CQDs with hydrogel with better recyclability.
Analysis of travelling waves and propagating supports for a nonlinear model of flame propagation with a p-Laplacian operator and advection
Authors: Díaz Palencia José Luis , Rahman Saeed ur
Published: August 2023

In this paper, we propose a new model to characterize the behaviour of a flame driven by temperature and pressure variables. The model is formulated using a p-Laplacian operator, an advection term, and a nonlinear reaction (considering linear kinetics). First, the uniqueness and boundedness of the weak solutions are demonstrated. Subsequently, traveling wave solutions supported by the geometric perturbation theory are obtained. As a major outcome, minimum traveling wave speeds are shown to exist, for which the associated profiles of the solutions are purely monotonic with exponential behaviour. The assumptions considered in the analytical approach are further explored through a numerical assessment, and self-similar solutions are constructed to determine the evolution of the flame front in terms of the temperature and pressure variables.
Robust unenhanced peripheral magnetic resonance angiography using single-slab 3D chemical-shift-encoded GRASE
Authors: Maeng Hyunkyung , Kim Hahnsung , Sohn Jeong-Woo , Park Jaeseok
Published: August 2023

Objective. To develop a novel, unenhanced magnetic resonance angiography (MRA) exploiting cardiac-gated, single-slab 3D chemical-shift-encoded gradient- and spin-echo (GRASE) imaging for robust background suppression. Approach. The proposed single-slab 3D GRASE employs variable-flip-angles (VFA) in the refocusing radio-frequency (RF) pulse train to promote sensitivity to blood flow as well as imaging encoding efficiency. Phase encoding blips are inserted between adjacent lobes of the switching readout gradients such that chemical shift-induced phase information is encoded into different locations in k-space. Based on the assumption that most background signals in the angiogram come from the fatty tissues, the proposed method directly separates angiograms from fatty background tissue signals from highly incomplete measurements by solving a constrained optimization problem with sparsity prior. Numerical simulations and experiments were performed to validate the effectiveness of the proposed method in healthy volunteers as compared with conventional fresh blood imaging (FBI). Main results. Compared with conventional FBI, the proposed method yields clearer delineation of small branching arteries and robust fatty background suppression without apparent loss of signals. Significance. We have successfully demonstrated the feasibility of the proposed, single-slab 3D VFA GRASE with chemical-shift-encoded reconstruction for the generation of robust unenhanced peripheral MRA.
MUE-CoT: multi-scale uncertainty entropy-aware co-training framework for left atrial segmentation
Authors: Hao Dechen , Li Hualing , Zhang Yonglai , Zhang Qi
Published: August 2023

Objective. Accurate left atrial segmentation is the basis of the recognition and clinical analysis of atrial fibrillation. Supervised learning has achieved some competitive segmentation results, but the high annotation cost often limits its performance. Semi-supervised learning is implemented from limited labeled data and a large amount of unlabeled data and shows good potential in solving practical medical problems. Approach. In this study, we proposed a collaborative training framework for multi-scale uncertain entropy perception (MUE-CoT) and achieved efficient left atrial segmentation from a small amount of labeled data. Based on the pyramid feature network, learning is implemented from unlabeled data by minimizing the pyramid prediction difference. In addition, novel loss constraints are proposed for co-training in the study. The diversity loss is defined as a soft constraint so as to accelerate the convergence and a novel multi-scale uncertainty entropy calculation method and a consistency regularization term are proposed to measure the consistency between prediction results. The quality of pseudo-labels cannot be guaranteed in the pre-training period, so a confidence-dependent empirical Gaussian function is proposed to weight the pseudo-supervised loss. Main results. The experimental results of a publicly available dataset and an in-house clinical dataset proved that our method outperformed existing semi-supervised methods. For the two datasets with a labeled ratio of 5%, the Dice similarity coefficient scores were 84.94% ± 4.31 and 81.24% ± 2.4, the HD95 values were 4.63 mm ± 2.13 and 3.94 mm ± 2.72, and the Jaccard similarity coefficient scores were 74.00% ± 6.20 and 68.49% ± 3.39, respectively. Significance. The proposed model effectively addresses the challenges of limited data samples and high costs associated with manual annotation in the medical field, leading to enhanced segmentation accuracy.
Multi-level spatial-temporal and attentional information deep fusion network for retinal vessel segmentation
Authors: Huang Yi , Deng Tao
Published: August 2023

Objective. Automatic segmentation of fundus vessels has the potential to enhance the judgment ability of intelligent disease diagnosis systems. Even though various methods have been proposed, it is still a demanding task to accurately segment the fundus vessels. The purpose of our study is to develop a robust and effective method to segment the vessels in human color retinal fundus images. Approach. We present a novel multi-level spatial-temporal and attentional information deep fusion network for the segmentation of retinal vessels, called MSAFNet, which enhances segmentation performance and robustness. Our method utilizes the multi-level spatial-temporal encoding module to obtain spatial-temporal information and the Self-Attention module to capture feature correlations in different levels of our network. Based on the encoder and decoder structure, we combine these features to get the final segmentation results. Main results. Through abundant experiments on four public datasets, our method achieves preferable performance compared with other SOTA retinal vessel segmentation methods. Our Accuracy and Area Under Curve achieve the highest scores of 96.96%, 96.57%, 96.48% and 98.78%, 98.54%, 98.27% on DRIVE, CHASE_DB1, and HRF datasets. Our Specificity achieves the highest score of 98.58% and 99.08% on DRIVE and STARE datasets. Significance. The experimental results demonstrate that our method has strong learning and representation capabilities and can accurately detect retinal blood vessels, thereby serving as a potential tool for assisting in diagnosis.
Atmospheric pressure plasma treatment of skin: penetration into hair follicles
Authors: Konina Kseniia , Freeman Theresa A , Kushner Mark J
Published: August 2023

Sterilization of skin prior to surgery is challenged by the reservoir of bacteria that resides in hair follicles. Atmospheric pressure plasma jets (APPJs) have been proposed as a method to treat and deactivate these bacteria as atmospheric plasmas are able to penetrate into structures and crevices with dimensions similar to those found in hair follicles. In this paper, we discuss results from a computational investigation of an APPJ sustained in helium flowing into ambient air, and incident onto a layered dielectric similar to human skin in which there are idealized hair follicles. We found that, depending on the location of the follicle, the bulk ionization wave (IW) incident onto the skin, or the surface IW on the skin, are able to launch IWs into the follicle. The uniformity of treatment of the follicle depends on the location of the first entry of the plasma into the follicle on the top of the skin. Typically, only one side of the follicle is treated on for a given plasma pulse, with uniform treatment resulting from rastering the plasma jet across the follicle over many pulses. Plasma treatment of the follicle is sensitive to the angle of the follicle with respect to the skin, width of the follicle pocket, conductivity of the dermis and thickness of the underlying subcutaneous fat layer, the latter due to the change in capacitance of the tissue.
A novel coarse-grained modeling and simulation for the microstructure evolution of ferrofluids
Authors: Zhao Penghui , Du Tianxiang , Zeng Yaoxiang , Pan Zhongwen , Ma Ning , Zhao Jiamin , Dong Xufeng
Published: August 2023

Ferrofluid (FF) has attracted more and more attention due to its tunable rheological properties, in which the microstructure under a magnetic field plays an important role in these properties. In this study, an innovative coarse-grained (CG) model of FF is presented for the first time to capture the microstructure evolution of FF at the nanoscale. The potential functions of carrier liquid for FF CG models are obtained by the iterative Boltzmann inversion method, and the CG nonbonded interaction between the magnetic particles (MPs) is obtained via the strain energy conservation. Then, CG molecular dynamics (CGMD) simulations are used to study the microstructure evolutions of FF under different magnetic fields. Notably, we demonstrate the existence of a carrier liquid adsorption layer on the MPs surface, and its thickness is calculated. The staggered arrangement style of MPs in the chains is also revealed by the CGMD method. The present FF CG model has fully considered the carrier liquid molecular structure and interaction with the MPs, and the CGMD is used to solve the problem that classical molecular dynamics cannot simulate the microstructure of FF, making the simulation results more in line with the actual situation.
Effects of recycling on polystyrene shape memory polymers for in-situ resource utilization
Authors: Nelson Maggie A , Siwakoti Midhan , Cardon Rylee , Triggs Eldon , Mailen Russell W
Published: August 2023

One-way, thermoplastic shape memory polymers (SMPs) used as actuators for self-folding origami are typically single-use materials that would be decommissioned upon completion of mission objectives. As a result, there exists an abundance of unutilized, single-use SMP waste. In-situ resource utilization (ISRU) and recycling offer solutions for the use and integration of sustainable SMP material infrastructures on Earth and for long-duration space missions. Unfortunately, mechanical recycling causes degradation of material properties. Therefore, it is imperative to quantify the effects of recycling on SMP properties. Herein, we utilize a thermo-mechanical recycling method applied to polystyrene SMPs. After recycling, we conduct Fourier transform infrared spectroscopy, differential scanning calorimetry, and dynamic mechanical analysis to investigate changes to the chemical structure, viscoelastic properties, and shape recovery response of the polymer. The results indicate negligible changes to the viscoelastic and shape recovery properties of the recycled material from one to six recycling sequences (extrusions) when compared to the non-recycled material. The most evident form of deterioration occurred in the physical appearance of the material. Otherwise, the shape recovery performance and thermo-mechanical properties remained consistent after recycling. Therefore, the recovery characteristics (recovery ratio, recovery time, and actuation stress) do not change significantly after six recycling sequences, making this material viable for ISRU applications in space environments.
Adiabatic quantum-flux-parametron boosters for long interconnection and large fanouts
Authors: Mizushima Naoya , Takeuchi Naoki , Yamanashi Yuki , Yoshikawa Nobuyuki
Published: August 2023

Adiabatic quantum flux parametron (AQFP) is energy-efficient superconducting logic that operates with zero static energy consumption and extremely small dynamic energy consumption thanks to the adiabatic switching of the logic gates. One drawback in AQFP logic circuits is the wire length and fan-out limitations because of the low driving ability of the logic gates, which results in a large circuit area and significant latency. In the present study, we propose AQFP boosters with high driving ability. Two types of AQFP boosters are proposed: one is composed of a parallel connection of AQFP buffers, and the other uses multistage buffers driven by one excitation clock. We evaluated the maximum wire length of the proposed boosters by circuit simulations, including thermal noises, and found that the maximum wire length is 3.9 mm for fan-out one and 1 mm for fan-out four. We implemented the boosters and demonstrated their correct operations at low-speed tests. We also demonstrated a 5-to-31 decoder using the proposed boosters. It was shown that the circuit area, latency, and energy consumption were improved by about 30% compared to the design without the boosters.
E–I characteristics and critical currents of small Bi-2223/Ag coil thermally stabilized by solid and liquid nitrogen compared to water ice
Authors: Búran M , Kopera L , Melišek T , Kováč P
Published: August 2023

A small-sized coil of helically wound Bi-2223/Ag tape was measured in liquid/solid nitrogen (LN2/SN2), and also in water (H2O) ice at external fields of 0–8 T and in a temperature range of 10–77 K. This work is especially focused on the coil stability for current amplitudes above the critical current criterion of 1 µV cm−1. While the E–I characteristics measured under the critical current criterion did not show any substantial variances at these different cooling conditions, significant differences were observed above the critical current magnitude, mainly upon cooling by solid nitrogen and water ice. The results confirm improved thermal stability for the coil measured in sub-cooled water ice compared to solid nitrogen. Consequently, cooling by water ice could be interesting for future applications of high-temperature superconducting coils.
Novel two-step procedure for measuring I
c vs. tensile stress of commercial REBCO tape
Authors: Zhang Zili , Chen Sikan , Wang Lei , Liu Hui , Liu Yan , Zhao Yue , Suo Hongli , Wang Qiuliang
Published: August 2023

This paper presents a novel two-step procedure for measuring the critical current (I
c) properties as a function of tensile stress. The proposed method completely eliminates the possible negative effect of the voltage tap used during the tensile procedure, allowing the actual I
c irreversible degradation stress to be clearly determined. Six different commercial REBCO tapes from five manufacturers were tested. The I
c value does not degrade until the stress reaches the ‘inflection area’ in the tensile curve, which corresponds to the most pronounced transformation step from elastic to plastic deformation. This allows easy estimation of the stress corresponding to I
c irreversible degradation by a simple and accurate cryogenic tensile curve instead of complicated in-situ I
c tensile measurement. A feasible composite-material tensile model is established to explain the phenomenon. In addition, fatigue measurements on a commercial REBCO tape from Shanghai Superconductor technology show that the tape can withstand 10 000 cycles under 580 MPa and over 5000 cycles under 695 MPa, which also is consistent with the proposed composite-materials tensile model and is confirmed by the EBSD experiments on the Hastelloy substrate. This research provides better insight and tools for designing and fabricating extremely high-field magnets.
Nonlinear optical and luminescence studies on Zinc Alumino-Boro-Silicate glasses co-doped with Dy3+ and Sm3+ ions for optical limiting and W-LEDs applications
Authors: Monisha M , Rajput Vinod K , Naraharisetty Sri Ram G , Sayyed M I , Altowyan Abeer S , Kamath Sudha D
Published: August 2023

In the present work, Dy3+ and Sm3+ co-doped Zinc Alumino-Boro-Silicate (ZABS) glasses doped with an optimized Dy3+ concentration (0.5 mol%) and varying Sm3+ concentrations are prepared using a conventional melt-quenching method. Optical absorption spectra showed the signature of Dy3+ and Sm3+ peaks through possible transitions in the range of 300–1800 nm. The optical bandgap of the glasses is obtained in the range of 4.2 to 3.9 eV. The emission curves aswellas decay lifetimes of Dy3+ and Sm3+ ions under 350 nm and 402 nm excitation were investigated using photoluminescence studies. Through the Inokuti-Hirayama (I-H) energy fitting model, the nature of energy transfer between Dy3+ and Sm3+ is found to be a ‘dipole–dipole’ type. Neutral to near warm white light emissions from the co-doped glasses were evaluated through colour chromaticity and correlated colour temperature calculations. The nonlinear optical measurements showed the reverse saturable absorption behaviour of the glasses whose nonlinear absorption coefficients (β) decreased with higher concentrations of Sm3+. Among the prepared glasses, ZABSDS1 (Sm3+ 0.1 mol%) glass showed the highest nonlinear coefficient (3.56 × 10−12 W cm−2) and lowest optical limiting (37.5 × 1011 W cm−2) threshold. From the overall studies, the suitability of the prepared glasses for White LEDs and optical limiting laser device applications were realized.
Dynamics in sliding set of planar sector-wise linear systems
Authors: Han Qianqian , Huan Song-Mei
Published: August 2023

For piecewise smooth dynamical systems the existence and properties of some special kinds of sliding points are very important to determine the dynamics (whether local or global), and are also very essential in studying DIBs (i.e. discontinuity induced bifurcations) related to sliding motions. In this paper, we mainly study the inner dynamics of the sliding set of a general planar sector-wise linear differential systems, including the definitions, existence and stability of all special sliding points. Specially, by studying the case when the two zones are separated by straight lines, we obtain explicit dependence on system parameters of the existence, stability and number of all kinds of special sliding points for the planar sector-wise linear systems. Moreover, we provide concrete examples to illustrate our main results and their application in studying DIBs.
Dust-ion-acoustic shock waves in the presence of (r, q) distributed electrons
Authors: Khan Majid , Huzaif Syed Muhammad , Kamran M
Published: August 2023

A three-component dusty plasma system, with non-Maxwellian electrons, is investigated. The ions are considered to be mobile, the (spherical) dust is assumed to be stationary with charge- fluctuations, and the electrons follow the generalized

r
,
q

velocity distribution function (VDF). The respective Burger’s equation, which manifests a shock structure, is derived by employing a reductive perturbation technique (RPT). It is deduced that dust charge fluctuations induce shock potential in a collisionless plasma system. The resultant perturbed potential is evaluated as affected by different plasma parameters, e.g. the ratios of electron to ion temperature (σ

i
) and equilibrium densities (μ), and the non-thermal indices r and q. The shock amplitude is seen to decrease when the value of σ

i
is increased, and vice versa, whereas an opposite trend is observed for μ. It is found that for r = 0 and increasing values of spectral index q, amplitude of the potential distribution enhances while its width decreases. It is further noted that non-Maxwellian VDF significantly modifies the potential distribution. For the limiting case, namely, r = 0 and q → ∞ , the corresponding Maxwellian results are retrieved which benchmarks our findings. Present work will be useful in understanding the nonlinear propagation of dust-ion-acoustic shock waves in system where non-thermal population—as caused by various physical processes—of electrons are observed.
Effects of gravitational lensing by Kaluza-Klein black holes on neutrino oscillations
Authors: Chakrabarty Hrishikesh , Chatrabhuti Auttakit , Malafarina Daniele , Silasan Bhuddhanubhap , Tangphati Takol
Published: August 2023

We study gravitational lensing of neutrinos in a Kaluza-Klein black hole spacetime and compare the oscillation probabilities of neutrinos with the case of lensing by black holes in General Relativity. We show that measuring neutrino oscillations in curved spacetimes may allow us to distinguish the two kinds of black holes even in the weak-field limit, as opposed to what happens for the weak lensing of photons. This promises to become an useful tool for future measurements of the properties of black hole candidates and possibly help to constrain the validity of alternative theories of gravity.
Tracking the validity of the quasi-static and sub-horizon approximations in modified gravity
Authors: Orjuela-Quintana J. Bayron , Nesseris Savvas
Published: August 2023

Within the framework of modified gravity, the quasi-static and sub-horizon approximations are widely used in analyses aiming to identify departures from the concordance model at late-times. In general, it is assumed that time derivatives are subdominant with respect to spatial derivatives given that the relevant physical modes are those well inside the Hubble radius. In practice, the perturbation equations under these approximations are reduced to a tractable algebraic system in terms of the gravitational potentials and the perturbations of involved matter fields. Here, in the framework of f(R) theories, we revisit standard results when these approximations are invoked using a new parameterization scheme that allows us to track the relevance of each time-derivative term in the perturbation equations. This new approach unveils correction terms which are neglected in the standard procedure. We assess the relevance of these differences by comparing results from both approaches against full numerical solutions for two well-known toy-models: the designer f(R) model and the Hu-Sawicki model. We find that: i) the sub-horizon approximation can be safely applied to linear perturbation equations for scales 0.06 h/Mpc ≲ k ≲ 0.2 h/Mpc, ii) in this “safety region”, the quasi-static approximation provides a very accurate description of the late-time cosmological dynamics even when dark energy significantly contribute to the cosmic budget, and iii) our new methodology performs better than the standard procedure, even for several orders of magnitude in some cases. Although, the impact of this major improvement on the linear observables is minimal for the studied cases, this does not represent an invalidation for our approach. Instead, our findings indicate that the perturbation expressions derived under these approximations in more general modified gravity theories, such as Horndeski, should be also revisited.
Erratum to “Relativistic solutions for diatomic molecules subject to pseudoharmonic oscillator in arbitrary dimensions”
Authors: Ortakaya Sami
Published: August 2023

Klein–Gordon equation with pseudoharmonic oscillator has been corrected through physical acceptable solutions. In a way, we correct the energy spectra related to its behavior versus potential parameter D
e.
Time-dependent variational approach to solve multi-dimensional time-dependent Schrödinger equation
Authors: He 何 Mingrui 明睿 , Wang 王 Zhe 哲 , Yao 姚 Lufeng 陆锋 , Li 李 Yang 洋
Published: August 2023

We present an efficient approach to solve multi-dimensional time-dependent Schrödinger equation (TDSE) in an intense laser field. In this approach, each spatial degree of freedom is treated as a distinguishable quasi-particle. The non-separable Coulomb potential is regarded as a two-body operator between different quasi-particles. The time-dependent variational principle is used to derive the equations of motion. Then the high-order multi-dimensional problem is broken down into several lower-order coupled equations, which can be efficiently solved. As a demonstration, we apply this method to solve the two-dimensional TDSE. The accuracy is tested by comparing the direct solutions of TDSE using several examples such as the strong-field ionization and the high harmonic generation. The results show that the present method is much more computationally efficient than the conventional one without sacrificing accuracy. The present method can be straightforwardly extended to three-dimensional problems. Our study provides a flexible method to investigate the laser-atom interaction in the nonperturbative regime.