bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of linearized elasticity models with point sources in weighted Sobolev spaces: applications in tissue contraction
Authors: Boon Wietse M. , Vermolen Fred J.
Published: June 2023

In order to model the contractive forces exerted by fibroblast cells in dermal tissue, we propose and analyze two modeling approaches under the assumption of linearized elasticity. The first approach introduces a collection of point forces on the boundary of the fibroblast whereas the second approach employs an isotropic stress point source in its center. We analyze the resulting partial differential equations in terms of weighted Sobolev spaces and identify the singular behavior of the respective solutions. Two finite element method approaches are proposed, one based on a direct application and another in which the singularity is subtracted and a correction field is computed. Finally, we confirm the validity of the modeling approach, demonstrate convergence of the numerical methods, and verify the analysis through the use of numerical experiments.
Essential Service Products as Channels for COVID-19 Awareness and Behavior Change: A Narrative Review
Authors: Pathak Vineet Kumar , Priya Karpaga P. , Panigrahi Sunil Kumar , Raj Utsav , Kumar Mohan
Published: June 2023

Coronavirus disease 2019 (COVID-19) is here to stay. Nonpharmacological interventions such as hand hygiene, social distancing, and respiratory hygiene have remained the mainstay to curb the spread of the virus, and these are sustainable. To understand the information, education, and communication (IEC) efforts undertaken during previous pandemics and successful behavior change strategies that may be applicable to ongoing COVID-19 pandemic, we conducted a narrative review of articles using PubMed search on September 11, 2022. The results highlighted that reinforced IEC is the need of the hour in efforts against COVID-19 pandemic. The communication strategy during a pandemic should be of three stages aligned to the objectives of building a basic understanding and knowledge in the target population: building an awareness of the threat; personal actions to minimize the impact; and reinforcing the need for appropriate actions to minimize disease transmission, in that order. An innovative strategy of displaying IEC on the daily essential products can result in a sustainable solution that might result in a “felt need” in the community to follow COVID-19 appropriate behavior. A broad base of stakeholders' engagement with civil bodies, nongovernmental organizations, private sectors with well-defined responsibilities and accountability would offer an enabling environment for these efforts in ultimately curbing the COVID-19 pandemic.
How to Approach Below-the-Ankle Arterial Interventions
Authors: Arslan Bulent , Madassery Sreekumar
Published: June 2023

Critical limb ischemia, also referred to as chronic limb-threatening ischemia, is a major medical problem leading to limb amputations if not managed properly with a multispecialty team. Establishment of sufficient arterial flow to the foot is an integral part of this care. During the past two to three decades, arterial revascularization has become primarily endovascular with open surgical approaches significantly diminished in comparison. As techniques, tools, and experiences of the interventionalist have improved, the ability to recanalize more complex lesions has become more commonplace. We are at an age that even the arteries below the ankle can be accessed for complex interventions and even be recanalized if necessary. This article will discuss common arterial interventions performed below the ankle.
Treatment of Difficult, Calcified Lesions: Plaque Modification Strategies
Authors: Haddad Mustafa , Scheidt Matthew J.
Published: June 2023

Endovascular management of peripheral arterial disease is continually evolving. Most changes focus on addressing the challenges that hinder optimal patient outcomes; one of the most significant is how to best treat calcified lesions. Hardened plaque results in a variety of technical issues including impaired device delivery, decreased luminal revascularization, poor stent expansion, heightened risk of in-stent stenosis or thrombosis, and increased procedural time and cost. For this reason, plaque modification devices have been developed to mitigate this issue. This paper will describe these strategies and provide the reader with an overview of devices that can be used to treat chronically hardened lesions.
Controlled-Release Levodopa for the Treatment of Rapid Motor Fluctuations in Parkinson's Disease Subjects with Subthalamic Nucleus Deep Brain Stimulation
Authors: Onder Halil , Comoglu Selcuk
Published: June 2023

Objectives We aimed to investigate the efficiency of controlled-release levodopa/benserazide (Madopar HBS) use during daytime in our pilot study on advanced-stage Parkinson's disease (PD) subjects with deep brain stimulation of the subthalamic nucleus (STN-DBS) therapy.

Methods We have evaluated all PD subjects with STN-DBS who had admitted to our outpatient polyclinic between February 2022 and March 2022. Among these patients, those who were taking levodopa therapy at least five times throughout the day and the efficiency of levodopa lasted less than 3 hours were detected. The standard levodopa therapy was switched to Madopar HBS in all patients who accepted the therapy chance and the clinical evaluation of the patients on Madopar HBS therapy was performed in the second month of the therapy.

Results Ultimately, the follow-up of all four patients in whom the levodopa therapy was changed to Madopar HBS yielded a significant reduction in the “off” periods and improvement in the PSQ-39 scores.

Conclusion We suggest the use of Madopar HBS in PD patients with STN-DBS surgery suffering from motor fluctuations, particularly in the subgroup with milder dyskinesias. Future study results of a large number of PD subjects with STN-DBS therapy are warranted to confirm our observations. The results of these studies may provide critical applications in clinical practice.
Negative Chronotropic Cardiovascular Changes in Lumbar Spine Surgery: A Potential Spinal-Cardiac Reflex?
Authors: Sultan Kashif Ali , Ashraf Mohammad , Chaudhary Attika , Al Salloum Laulwa , Ghulam Naseeruddin , Ahmed Nazir , Ismahel Hassan , Farooq Minaam , Iqbal Javed , Ashraf Naveed
Published: June 2023

Cardiovascular changes following lumbar spine surgery in a prone position are exceedingly rare. Over the past 20 years, a total of six cases have been published where patients experienced varying degrees of bradycardia, hypotension, and asystole, which could be attributed to intraoperative dural manipulation. As such, there is emerging evidence for a potential neural-mediated spinal-cardiac reflex. The authors report their experience of negative chronotropy during an elective lumbar spine surgery that coincided with dural manipulation and review the available literature. A 34-year-old male presented with a long-standing history of lower back pain recently deteriorating to bilaterally radiating leg pain, with restricted left leg raise, and numbness at the left L5 dermatomal territory. The patient was an athletic police officer with no comorbidities or past medical history. Magnetic resonance imaging lumbosacral spine revealed spinal stenosis most pronounced at L4/L5 and disc bulges at L3/L4 and L5/S1. The patient opted for lumbar decompression surgery. After an unremarkable comprehensive preoperative workup, including cardiac evaluation (electrocardiogram, echocardiogram), the patient was induced general anesthesia in a prone position. A lumbar incision was made from L2 to S1. When the left L4 nerve root was retracted while removing the prolapsed disc at L4/L5, the anesthetist cautioned the surgeon of bradycardia (34 beats per minute [bpm]), and the surgery was immediately stopped. The heart rate improved to 60 bpm within 30 seconds. When the root was later retracted again, a second episode of bradycardia occurred for 4 minutes with heart rate declining to 48 bpm. The surgery was stopped, and after 4 minutes, the anesthetist administered 600 µg of atropine. The heart rate then rose to 73 bpm within 1 minute. Other potential causes for bradycardia were excluded. The total blood loss was estimated to be 100 mL. He remains well at his 6-month follow-up and has returned to work as normal. Akin to previously published cases, each episode of bradycardia coincided with dural manipulation, which may indicate a possible reflex between the spinal dura mater and the cardiovascular system. Such a rare adverse event may occur even in seemingly healthy, young individuals, and anesthetists should caution the operating surgeon of bradycardias to exclude operative manipulation of the dura as the cause. While this phenomenon is only reported in a handful of lumbar spine surgery cases, it provides evidence for a potential spinal-cardiac physiological reflex in the lumbar spine that may be neural mediated and should be investigated further.
Drug-Coated Balloon versus Drug-Eluting Stent: The Debate of Leave Nothing Behind
Authors: Keefe Nicole , Shull Trevor , Botea Lev , McGinigle Katharine
Published: June 2023

Endovascular techniques for peripheral artery disease have changed significantly in the past 10 years with advances in technology and data. Treatment of superficial femoral disease is complex secondary to the length, degree of calcification, high rate of chronic total occlusion, and areas of flexion within this vessel. Use of drug-coated devices has increased the interventionalist's toolbox with the objective to improve freedom from target lesion revascularization and primary patency. There remains debate as to which devices may reach these goals while also limiting overall morbidity and mortality. This article aims to highlight recent advances in the literature regarding the use of drug-coated devices.
Analysis of air bearing torsion pendulum moment of inertia measurements including nonlinear oscillation and damping
Authors: Wang Jun , Zheng Liu , Wang Yixu , Miao Na , Zhang Xiaolin
Published: June 2023

For precise measurement of the moment of inertia (MOI) of asymmetric objects, using an air bearing torsional pendulum, the nonlinearity of the torsion bar and the damping effect caused by the interaction between air and sample need to be included in the analysis. The instantaneous undamped natural frequency and instantaneous damping coefficient of the motion are obtained from the Hilbert transform of the angular displacement signal and are used for data fitting to calculate the MOI. Measurements for algorithm verification were made using a special sample with large windvanes to increase the damping effect. The nonlinear analysis of the MOI experimental results indicated a relative error of less than 0.1% compared with 0.3% for classical linear analysis of the data.
A versatile and customizable low-cost printed multipass microrheometer for high-throughput polymers rheological experimentation
Authors: Tammaro D. , Maffettone P. L.
Published: June 2023

We report the design of a multipass microrheometer that can be fully customizable at a low cost and reasonable time, which allows us to perform experiments rapidly and in a broad range of shear rates (i.e., from 0.1 to 100 s−1), using small amounts of material (i.e., just some milligrams). Additionally, the low-cost approach opens for an easy parallelization of the setup that makes it suitable for high-throughput rheological experimentation of polymer melts (HT-Rheo-E). The novel rheometer consists of a microchannel (i.e., a microcapillary or a microslit) in which the fluid flows driven by two controlled millimetric pistons (diameter of 2 mm). Two piezoelectric miniaturized pressure sensors are placed at the microchannel entrance and exit to record the pressure drop across the capillary during the motion. The current work reports the design of the rheometer with two different cross sections of the microchannel, i.e., circular and rectangular, and measurements of the shear viscosity with a Newtonian and a non-Newtonian polymer over a wide range of shear rates using less than 1 g of sample. We demonstrate that the current multipass microrheometer can measure viscoelastic properties of polymers by applying an oscillatory flow. The printed setup is of potential interest for applications in quality control in industrial production, in natural systems (such as starch-based mixtures) and academic research where rapid and repeated measurements using limited milligrams of polymer are required (e.g., biological systems).
Performance improvement of yellow flip-chip mini-LEDs via full-angle distributed Bragg reflector
Authors: Zhao Xiaoyu , Sun Yuechang , Shi Lang , Zhou Shengjun
Published: June 2023

Miniaturized light-emitting diodes (mini-LEDs) have gained much attention for liquid crystal displays back-light and self-emissive displays. However, the unsatisfactory performance of InGaN long-wavelength mini-LEDs hinders their practical applications. Herein, we develop a full-angle distributed Bragg reflector (DBR) and investigate its impact on the performance of yellow flip-chip mini-LEDs. The full-angle DBR consists of different stacks of Ti3O5/SiO2 layers that are optimized for multiple central wavelengths. Compared to conventional single-DBR stacks, such full-angle DBR enables wider reflectance bandwidth and less dependence of reflectance on the light incident angle from 0° to 50°. Specifically, full-angle DBR features high reflectance beyond 99% from 447 to 580 nm at an incident angle of 50°. Full-angle DBR is found to enhance the electric field intensity at the top of devices, indicating that light extraction efficiency is promoted. As a result, yellow flip-chip mini-LEDs with full-angle DBR show higher light output power than those without DBR at the same currents. Our work paves a way to improve the performance of small-size emitters with long wavelength.
Tripartite evolution game between susceptible and infected groups and the governmental prevention and control department amid major epidemics
Authors: Liu Aijun , Yang Fan , Wang Guangwei , Qi Haosheng
Published: June 2023

A major epidemic is an evolutionary process of a complex system, which involves multiple parties, such as different groups and prevention and control departments. Thus, it is of practical importance to establish a multi-party game evolution model and study internal laws for curbing an epidemic. This study proposes a method of the combination of the infectious disease warehouse model and evolutionary game. We aim to explore the effects of the prevention and control policies and to have an insight into the influence of social public strategy choices with two-state (susceptible and infected state based on the warehouse model) people. Thus, we construct a tripartite evolutionary game model for two principal groups and the governmental prevention and control department during an epidemic, calculate the replicator dynamics equation and its evolutionary stability value, and conduct a sensitivity analysis of the key parameters. The results show that the governmental prevention and control department’s strategy evolves the fastest. The infected (I) group relates to the loss apportionment ratios α (under efficient prevention and control strategy) and β (under inefficient prevention and control strategy), and the susceptible (S) group is easily influenced by opportunity cost e (average opportunity cost of individuals in Group S with crisis awareness).
Optoelectronic properties of quasi-two-dimensional perovskite light-emitting diodes via poly(9-vinylcarbazole) interlayer modification
Authors: Tu Peng , Cai Xiangcheng , Ai Yansong , He Hongshen , Shen Peng , Zhou Yuanming , Mei Fei
Published: June 2023

Perovskite light-emitting diodes (PeLEDs) have attracted much attention due to their excellent performance. In this work, phenylethylamine bromide (PEABr) was employed to modify perovskite phases, while Poly(9-vinylcarbazole) (PVK) was added as a hole transport layer between perovskite and PEDOT:PSS to engineer the device structure, which is predicted to improve the optoelectronic performance of PeLEDs synergistically. The doping of PEABr in MAPbBr3 can improve the radiative recombination of the emission layer through the formation of two-dimensional perovskite phases and modified film morphology. When the ratio of MAPbBr3:PEABr is 1:0.25, the maximum luminance of the optimal device increased from 80 to 9000 cd/m2 and the maximum external quantum efficiency increased from 0.02% to 1.63% compared with the control device without PEABr doping. In addition, the hole injection ability of the device is further improved by adding PVK as the hole transport layer. The introduction of PVK can also facilitate the interface modification via surface defect passivation. When the PVK concentration is 10 mg/ml, the maximum current efficiency and external quantum efficiency of the optimal device are increased to 13.70 cd/A and 2.70%, respectively. These findings can provide a basis for the enhanced performance of PeLEDs.
Flow field characteristics of a 127-pin rod bundle with hexagonal spacer grids
Authors: Menezes Craig , Melsheimer Trevor , Hassan Yassin A.
Published: June 2023

A determination of nominal flow phenomena in liquid metal fast reactor (LMFR) fuel assemblies is critical toward generation-IV reactor development. Axially positioned spacer grids are used to maintain the geometry of hexagonal rod bundles and simultaneously introduce perturbations in the flow. Three-dimensional (3D) printed asymmetric honeycomb spacer grids were installed in a prototypical 127-pin LMFR fuel assembly model to study complex fluid dynamics interactions induced by the spacer grid and rods. To characterize flow dynamics in this intricate geometry, time-resolved particle image velocimetry (TR-PIV) using the matched-index-of-refraction method was employed to obtain non-intrusive velocity measurements for three axial planes (one near-wall and two interior planes) at a Reynolds number of 6000. The statistical TR-PIV results compared sub-channel-dependent normalized time-averaged velocity, velocity fluctuations, Reynolds stress, vorticity, and turbulence kinetic energy distributions. TR-PIV line profiles characterized downstream spacer grid flow dynamics. Two-point spatial and spatial–temporal cross-correlation fields revealed local coherent structures and quantified convection velocities of traveling vortices. Spatial–temporal decomposition using dynamic mode decomposition (DMD) applied to the near-wall vorticity fields extracted turbulent structures and flow instabilities in the wake region of the spacer grid, along with their decay and frequency rates. Reduced-order velocity fields from DMD reconstructions identified the most energy-containing coherent structures persistent in the near-wall region. This research provides experimental data sets and analyses of flow behavior in rod bundles with hexagonal spacer grids. The results are critical toward LMFR design and geometry optimization, crucial for the validation of computational fluid dynamics and reduced-order flow models.
Machine learning based prediction of phase ordering dynamics
Authors: Chauhan Swati , Mandal Swarnendu , Yadav Vijay , Jaiswal Prabhat K. , Priya Madhu , Shrimali Manish Dev
Published: June 2023

Machine learning has proven exceptionally competent in numerous applications of studying dynamical systems. In this article, we demonstrate the effectiveness of reservoir computing, a famous machine learning architecture, in learning a high-dimensional spatiotemporal pattern. We employ an echo-state network to predict the phase ordering dynamics of 2D binary systems—Ising magnet and binary alloys. Importantly, we emphasize that a single reservoir can be competent enough to process the information from a large number of state variables involved in the specific task at minimal computational training cost. Two significant equations of phase ordering kinetics, the time-dependent Ginzburg–Landau and Cahn–Hilliard–Cook equations, are used to depict the result of numerical simulations. Consideration of systems with both conserved and non-conserved order parameters portrays the scalability of our employed scheme.
Discovering selective antiferroptotic inhibitors of the 15LOX/PEBP1 complex noninterfering with biosynthesis of lipid mediators
Authors: Dar Haider H. , Mikulska-Ruminska Karolina , Tyurina Yulia Y. , Luci Diane K. , Yasgar Adam , Samovich Svetlana N. , Kapralov Alexander A. , Souryavong Austin B. , Tyurin Vladimir A. , Amoscato Andrew A. , Epperly Michael W. , Shurin Galina V. , Standley Melissa , Holman Theodore R. , St. Croix Claudette M. , Watkins Simon C. , VanDemark Andrew P. , Rana Sandeep , Zakharov Alexey V. , Simeonov Anton  , Marugan Juan , Mallampalli Rama K. , Wenzel Sally E. , Greenberger Joel S. , Rai Ganesha , Bayir Hülya , Bahar Ivet , Kagan Valerian E.
Published: June 2023

Programmed ferroptotic death eliminates cells in all major organs and tissues with imbalanced redox metabolism due to overwhelming iron-catalyzed lipid peroxidation under insufficient control by thiols (Glutathione (GSH)). Ferroptosis has been associated with the pathogenesis of major chronic degenerative diseases and acute injuries of the brain, cardiovascular system, liver, kidneys, and other organs, and its manipulation offers a promising new strategy for anticancer therapy. This explains the high interest in designing new small-molecule–specific inhibitors against ferroptosis. Given the role of 15-lipoxygenase (15LOX) association with phosphatidylethanolamine (PE)-binding protein 1 (PEBP1) in initiating ferroptosis-specific peroxidation of polyunsaturated PE, we propose a strategy of discovering antiferroptotic agents as inhibitors of the 15LOX/PEBP1 catalytic complex rather than 15LOX alone. Here we designed, synthesized, and tested a customized library of 26 compounds using biochemical, molecular, and cell biology models along with redox lipidomic and computational analyses. We selected two lead compounds, FerroLOXIN-1 and 2, which effectively suppressed ferroptosis in vitro and in vivo without affecting the biosynthesis of pro-/anti-inflammatory lipid mediators in vivo. The effectiveness of these lead compounds is not due to radical scavenging or iron-chelation but results from their specific mechanisms of interaction with the 15LOX-2/PEBP1 complex, which either alters the binding pose of the substrate [eicosatetraenoyl-PE (ETE-PE)] in a nonproductive way or blocks the predominant oxygen channel thus preventing the catalysis of ETE-PE peroxidation. Our successful strategy may be adapted to the design of additional chemical libraries to reveal new ferroptosis-targeting therapeutic modalities.
Surface morphology transformation and densification behaviour of conventionally sintered AlFeCoNiSi high entropy alloys
Authors: Dewangan Sheetal Kumar , Nagarjuna Cheenepalli , Lee Hansung , Sharma Ashutosh , Ahn Byungmin
Published: June 2023

A preliminary study has been performed to understand the effect of pressureless sintering on the surface morphology of the AlFeCoNi alloy by the addition of the Si element. This study aims to determine the possibility of achieving the densification of high entropy alloy using the conventional sintering technique. The results indicate that the HEAs have a single-phase BCC structure even with the addition of Si. The thermodynamic simulation (CALPHAD) was used to predict the phase formation. The variation of crystallite sizes and lattice strains caused by sintering temperatures was also discussed. In addition, densification mechanisms occurring with the different sintering temperatures have been discussed. The formation of porosity was observed, however, the density of HEAs improved with increasing sintering temperature. Ultimately, it was suggested that the present HEAs required higher sintering temperatures and a longer time to achieve high density.
Antimonide-based high operating temperature infrared photodetectors and focal plane arrays: a review and outlook
Authors: Jia Chunyang , Deng Gongrong , Liu Lining , Zhao Peng , Song Guofeng , Liu Jianguo , Zhang Yiyun
Published: June 2023

Reduction in the size, weight, and power (SWaP) consumption of an infrared (IR) detection system is one of the critical challenges lying ahead for the development of IR detector technology, especially for mid-/long-wavelength IR wave bands, which calls for high operating temperature (HOT) IR photodetectors (PDs) with good sensitivity that would ease the burden for cooling systems. Emerging as strong competitors to HgCdTe detectors, antimonide (Sb)-based IR PDs and focal plane array (FPA) imagers have gradually stepped into real-world applications after decades of development thanks to their outstanding material properties, tunability of cutoff wavelengths, feasibility of device designs, and great potential for mass production with low costs. Meanwhile, the emerging demands of versatile applications seek fast, compact, and smart IR detection systems, in which the integration of Sb-based IR PDs on a Si platform enables direct information readout and processing with Si-based microelectronics. This paper reviews recent progress in Sb-based HOT IR PDs and FPAs, including the fundamental material properties and device designs based on bulk InAsSb, InAs/GaSb, and InAs/InAsSb type-II superlattices, together with the cutting-edge performance achieved. This work also covers new trends of development in Sb-based IR PDs, such as optical engineering for signal harvesting, photonic integration techniques, as well as metal organic chemical vapor deposition growth of antimonides. Finally, challenges and possible solutions for future studies are provided from the perspectives of material growth, device design, and imaging systems. New advances in response to these existing challenges may cast light on designs and strategies for achieving HOT devices at thermoelectric cooling temperatures (yet with lower costs), and more extensive emerging applications may be found.
Performance and reliability improvement of all-solution processed indium zinc oxide thin-film transistor by UV irradiation treatment
Authors: Hanifah Umu , Bermundo Juan Paolo S , Uenuma Mutsunori , Uraoka Yukiharu
Published: June 2023

Developing a low-temperature fabrication strategy for amorphous oxide semiconductors, such as amorphous indium zinc oxide (a-IZO) channel layers, for use in flexible oxide-based thin-film transistors (TFTs) is essential. In this work, high-performance and highly stable all-solution processed a-IZO TFTs were achieved by varying the duration of a photo-assisted combination treatment (UV combination treatment), which combines UV irradiation with a low heating temperature (115 °C) in an all-solution processed approach. From the experimental results, UV irradiation can activate the IZO source, drain, and gate electrodes which induces TFT switching. X-ray photoelectron spectroscopy analysis revealed oxygen vacancy (V
o) generation after the UV combination treatment which increased the carrier concentration and improved the conductivity of IZO. All-solution processed a-IZO TFTs with high performance and stability, high mobility (µ) up to 17.45 cm2 V−1 s−1, threshold voltage (Vth) = −1.2 V, and subthreshold swing (SS) = 0.64 V dec−1, were obtained at a low temperature of 115 °C for 90 min treatment time. The stability behavior of self-aligned top-gate, top-contact a-IZO TFT fabricated by UV combination treatment was investigated under positive bias stress (PBS) and negative bias stress (NBS) with the smallest ΔV
th of 2.4 V and 0.5 V for PBS and NBS, respectively. Our work shows that better stability indicated by the smaller ΔV
th is achieved due to reduction of interface trap density and moisture-related impurities, in particular on the activated electrode area. As a result, it can be inferred that UV combination treatment is a simple and promising method to enhance the electrical and stability performance of a-IZO TFTs even with the low-temperature process, which is useful for flexible devices.
A novel ultra-simplified flexure-based spring-mass device for relative gravimeter
Authors: Kong Meng Meng , Liu Peng Fei , Diao Wei Dong , Qian Min , Fan Kai , Zhang Jun Jian , Feng Zhi Hua
Published: June 2023

This study presents the design and test of a novel ultra-simplified flexure-based spring-mass device (NUFSMD) with high sensitivity for relative gravimeters. The NUFSMD is mainly composed of a highly sensitive spring based on flexure hinges (SFH) and a cantilever beam. When the change of gravity causes SFH to rotate, an amplified displacement can be obtained on the tail of the cantilever beam. The displacement is measured by a capacitive displacement sensor. The change of gravitational acceleration can be calculated based on the output of the sensor. A theoretical analysis of the working principle of the NUFSMD is established. A prototype NUFSMD is machined from 304 stainless steel and a series of experiments are carried out. The effectiveness of gravity measurement is demonstrated by finite element simulations and experiments. The experimental results show that the sensitivity of the NUFSMD is about 15.27 μGal nm−1, and the resolution is about 1.83 μGal. The designed NUFSMD shows outstanding performance. And the sensitivity and resolution of the NUFSMD can be further improved by increasing the number of flexible hinges connected in series. Compared with the existing spring-mass devices in high-precision relative gravimeters, the significant advantage of the NUFSMD is that it is simple in structure and easy to machine, which helps to greatly improve performance. Firstly, it is simple in structure, so it can be machined in one piece, which considerately contributes to stability and precision. Secondly, it is easy to machine, so it can be machined from high-performance but difficult-to-machine materials to improve its performance. Thirdly, there are a few parameters that need to be traded off for miniaturization because of the simple structure, so it is easy to be miniaturized to adapt to narrow measurement space. Therefore, it is expected to greatly improve the performance of the existing spring-mass device in relative gravimeters.
Use of the Airy beam to extend the micro-hole measurement range of an OCT system
Authors: Fan Zhili , Xia Min , Dong Bozhang , Yan Ganwei , Guo Wenping , Yang Kecheng , Li Wei
Published: June 2023

Optical coherence tomography (OCT) has the advantage of high precision in measuring micrometre-scale precision structures, but its measurement range is limited by the correlation with Rayleigh length of Gaussian beam. Therefore, this study used the Airy beam to extend the focal depth of the OCT system. The system’s coupled power was increased by 7.34 times when the sample position was at an optical defocus of 3 mm. Measurements of the resolution plate and silicon wafer sample showed that Airy beam OCT had a lateral resolution of 7.4 μm and the focal depth was >6 mm. While the focal depth of the Gaussian beam OCT with the equivalent lateral resolution was less than 1 mm. This improved OCT system demonstrates significant potential for sample measurements at large aspect ratios in the industrial surface detection field.
Assessment of compression-induced solid stress, fluid pressure and mechanopathological parameters in cancers in vivo using poroelastography
Authors: Khan MD Hadiur Rahman , Islam Md Tauhidul , Taraballi Francesca , Righetti Raffaella
Published: June 2023

Objective. Compression-induced solid stress (SSc) and fluid pressure (FPc) during ultrasound poroelastography (USPE) experiments are correlated with two markers of cancer growth and treatment effectiveness: growth-induced solid stress (SSg) and interstitial fluid pressure (IFP). The spatio-temporal distributions of SSg and IFP are determined by the transport properties of the vessels and interstitium in the tumor microenvironment. Approach. We propose a new USPE method for the non-invasive imaging of the local cancer mechanical parameters and dynamics of fluid flow. When performing poroelastography experiments, it may be difficult to implement a typical creep compression protocol, which requires to maintain a constant normally applied force. In this paper, we investigate the use of a stress relaxation protocol, which might be a more convenient choice for clinical poroelastography applications. Main results. Based on our finite element and ultrasound simulations study, we demonstrate that the SSc, FPc and their spatio-temporal distribution related parameters, interstitial permeability and vascular permeability, can be determined from stress relaxation experiments with errors below 10% as compared to the ground truth and accuracy similar to that of corresponding creep tests, respectively. We also demonstrate the feasibility of the new methodology for in vivo experiments using a small animal cancer model. Significance. The proposed non-invasive USPE imaging methods may become an effective tool to assess local tumor pressure and mechanopathological parameters in cancers.
Time-fractional (2+1)-dimensional navier-stokes equations: similarity reduction and exact solutions for one-parameter lie group of rotations
Authors: Verma Pooja , Pandit Sapna , Kumar Manoj , Kumar Vikas , Poonam Poonam
Published: June 2023

The current study is dedicated to solving the time-fractional (2+1)-dimensional Navier–Stokes model. The model has wide applications in blood flow, in the design of power stations, weather prediction, ocean currents, water flow in a pipe, air flow around the aircraft wings, the analysis of pollution, and many other areas of engineering. The Lie symmetry approach is applied to the governed time-fractional equation to fulfill this need. In the direction of exact solutions of the time-fractional equation first of all invariance condition is obtained in the presence of the Lie group. Consequently, infinitesimals are obtained with the help of the invariant condition. Moreover, these infinitesimals are utilized to obtain the subalgebras. Further, under each subalgebras similarity variables and similarity solutions are obtained which are used to find the reduced equations. These reduced equations are solved for exact solutions. The solutions of the reduced equations are further used to find the exact solutions of the main time-fractional (2+1)-dimensional Navier–Stokes equation with the help of similarity solutions under each subalgebra.
Canonical quantization of modified non-gauge invariant Einstein-Maxwell gravity and stability of spherically symmetric electrostatic stars
Authors: Ghaffarnejad Hossein
Published: June 2023

We consider a non-minimally coupled Einstein-Maxwell gravity with no U(1) symmetry property to study stability of an electrostatic star via canonical quantization approach and obtain that the stability is free of gauge field effects. By calculating the Hamiltonian density of the stellar system we show that the corresponding Wheeler-DeWitt wave functional is similar to a simple harmonic quantum Oscillator for which a non zero ADM mass of the system causes a quantization condition on the metric fields. Probability wave packets are described by the Hermit polynomials. Our mathematical calculations show that in this approach of quantum gravity the metric fields are regular for all values of the electric potential and so the quantized spacetime has not both of event and apparent horizons. The most probability of the quantized line element is for ground state of the system. To check validation of the model we use Bohr's correspondence principal and generate directly semi classical approach of the quantized metric states at large quantum numbers where they reach to Schwarzschild like metric according to the Birkhoff’s theorem. Also we check that the generated semi classical solutions are satisfied exact classical metric solutions which are obtained from Euler–Lagrange equations. We show that ‘charge to mass ratio’ of the electrostatic star is a constant defined by the coupling constant of the model and it is in accord to other alternative approaches.
Refractive index sensor based on multiple Fano resonances excited by MIM waveguide couplessd hexagonal nut and square ring resonators
Authors: Zhang Jian , Chen Tianshan , Chen Hanwen , Wang Xiangxian , Yang Hua , Qi Yunping , Tang Chaojun , Yu Jianli
Published: June 2023

This study proposed a micro-nano structure capable of generating multiple Fano resonances for refractive index sensing of gases and liquids. The structure consists of a metal-insulator-metal waveguide with a baffle and two resonators, one of hexagonal nut and one of square ring. The transmission spectrum shows that the designed structure can generate up to five Fano resonances tuned by different resonators. The data obtained are fitted by multi-mode interferometric coupling mode theory, and the results are in good agreement. The sensing performance of the structure is investigated in the refractive index ranges of 1.00–1.10 and 1.30–1.40. The corresponding maximum sensitivity and maximum figure of merit are up to 998 nm/RIU and 49016, 1026 nm/RIU and 14890, respectively. The designed structure can be used as gas and liquid sensors and have great potential for micro-nasno sensing and biochemical medicine applications.
Modeling the impacts of energetic disorder and charge transport on the exciton formation zone in organic light-emitting diodes
Authors: Qin Dashan , Zhao Hailiang
Published: June 2023

The width of exciton formation zone plays a vital role in determining the long-term stability of organic light-emitting diodes (OLEDs). Here, based on the general model of carrier device lifetimes, the dependences of the width and location of exciton formation zone on energetic disorder and charge transport have been simulated in OLEDs with emissive layer featuring hole and electron transport on host and guest molecules, respectively. The width of exciton formation zone increases with emissive layer’s energetic disorder increasing. The emissive layer with properly imbalanced carrier mobilities enables larger width of exciton formation zone than that with balanced carrier mobilities, due to the different hole and electron trap densities. Moreover, increasing hole transport layer’s hole mobility or decreasing electron transport layer’s electron mobility helps increase the width of exciton formation zone. There is no width of exciton formation zone obtained, when hole (electron) transport layer’s hole (electron) mobility is smaller than a certain value. The location of exciton formation relies on not only emissive layer’s carrier mobilities but also hole (electron) transport layer’s hole (electron) mobility. The general model provides the comprehensive picture to elucidate the roles of energetic disorder and charge transport in enhancing the stability of OLEDs, beneficial to improve the OLEDs designs towards the high stability at high luminance.
Conditionally exactly solvable Dirac potential, including x
1/3 pseudoscalar interaction
Authors: Ishkhanyan A M , Krainov V P
Published: June 2023

We study the solution of the 1D Dirac equation for a pseudoscalar potential, which includes an interaction term proportional to

x

1
/
3

and a

~
1
/
x

term with a fixed strength. This is a conditionally exactly solvable singular potential, symmetric with respect to the origin. A feature of the potential is that the effective potential for the Schrödinger equation, to which the Dirac equation can be reduced, splits into two known potentials: the first Stillinger potential and the second Exton potential for the positive and negative semiaxes, respectively. We present the solution and analyze the energy spectrum and wave functions of the bound states. Our results reveal notable differences between the Schrödinger and Dirac behaviors.
Supermassive black hole seeds from sub-keV dark matter
Authors: Friedlander Avi , Schon Sarah , Vincent Aaron C.
Published: June 2023

Quasars observed at redshifts z ∼ 6–7.5 are powered by supermassive black holes which
are too large to have grown from early stellar remnants without efficient super-Eddington
accretion. A proposal for alleviating this tension is for dust and metal-free gas clouds to have
undergone a process of direct collapse, producing black hole seeds of mass
 M
seed ∼ 105 M
⊙ around redshift z ∼ 17. For direct collapse to occur, a large
flux of UV photons must exist to photodissociate molecular hydrogen, allowing the gas to cool
slowly and avoid fragmentation. We investigate the possibility of sub-keV mass dark matter
decaying or annihilating to produce the UV flux needed to cause direct collapse. To do so, we
calculate the produced UV flux from dark matter annihilations and decays within the gas cloud's
halo and compare these to the requirements of the UV spectrum found by previous hydrodynamical
simulations. We find that annihilating dark matter with a mass in the range of 13.6 eV ≤ mdm
≤ 20 eV can produce the required flux while avoiding existing
constraints. A non-thermally produced dark matter particle which comprises the entire dark matter
abundance requires a thermally averaged cross section of 〈σv〉 ∼ 
10-35 cm3/s. Alternatively, the flux could originate from a thermal relic which comprises
only a fraction ∼ 10-9 of the total dark matter density. Decaying dark matter models which
are unconstrained by independent astrophysical observations are unable to sufficiently suppress
molecular hydrogen, except in gas clouds embedded in dark matter halos which are larger, cuspier,
or more concentrated than current simulations predict. Lastly, we explore how our results could
change with the inclusion of full three-dimensional effects. Notably, we demonstrate that if the
H2 self-shielding is less than the conservative estimate used in this work, the range
of both annihilating and decaying dark matter models which can cause direct collapse is
significantly increased.
Stable cosmological solutions in Horndeski theory
Authors: Mironov S. , Shtennikova A.
Published: June 2023

It is known that the construction of a completely stable solution in Horndeski theory is restricted very strongly by the so-called no-go theorem. Previously, various techniques have been used to avoid the conditions of the theorem. In this paper a new way of constructing stable solutions are shown in the general Horndeski theory. We considered the situation in which the unitary gauge studied earlier turns out to be singular. On this basis we construct a spatially flat, stable bouncing and genesis Universe solutions which are described by General Relativity with non-conventional scalar field.
Recent advances in NiO/Ga2O3 heterojunctions for power electronics
Authors: Lu Xing , Deng Yuxin , Pei Yanli , Chen Zimin , Wang Gang
Published: June 2023

Beta gallium oxide (β-Ga2O3) has attracted significant attention for applications in power electronics due to its ultra-wide bandgap of ~ 4.8 eV and the large critical electric field of 8 MV/cm. These properties yield a high Baliga’s figures of merit (BFOM) of more than 3000. Though β-Ga2O3 possesses superior material properties, the lack of p-type doping is the main obstacle that hinders the development of β-Ga2O3-based power devices for commercial use. Constructing heterojunctions by employing other p-type materials has been proven to be a feasible solution to this issue. Nickel oxide (NiO) is the most promising candidate due to its wide band gap of 3.6–4.0 eV. So far, remarkable progress has been made in NiO/β-Ga2O3 heterojunction power devices. This review aims to summarize recent advances in the construction, characterization, and device performance of the NiO/β-Ga2O3 heterojunction power devices. The crystallinity, band structure, and carrier transport property of the sputtered NiO/β-Ga2O3 heterojunctions are discussed. Various device architectures, including the NiO/β-Ga2O3 heterojunction pn diodes (HJDs), junction barrier Schottky (JBS) diodes, and junction field effect transistors (JFET), as well as the edge terminations and super-junctions based on the NiO/β-Ga2O3 heterojunction, are described.
Preparation and photodetection performance of high crystalline quality and large size β-Ga2O3 microwires
Authors: Wang Yuefei , Han Yurui , Gao Chong , Li Bingsheng , Ma Jiangang , Xu Haiyang , Shen Aidong , Liu Yichun
Published: June 2023

Ultrawide band gap semiconductors are promising solar-blind ultraviolet (UV) photodetector materials due to their suitable bandgap, strong absorption and high sensitivity. Here, β-Ga2O3 microwires with high crystal quality and large size were grown by the chemical vapor deposition (CVD) method. The microwires reach up to 1 cm in length and were single crystalline with low defect density. Owing to its high crystal quality, a metal–semiconductor–metal photodetector fabricated from a Ga2O3 microwire showed a responsivity of 1.2 A/W at 240 nm with an ultrahigh UV/visible rejection ratio (R
peak/R
400 nm) of 5.8 × 105, indicating that the device has excellent spectral selectivity. In addition, no obvious persistent photoconductivity was observed in the test. The rise and decay time constants of the device were 0.13 and 0.14 s, respectively. This work not only provides a growth method for high-quality Ga2O3 microwires, but also demonstrates the excellent performance of Ga2O3 microwires in solar-blind ultraviolet detection.
Application of modified partial capacity design on six-story L-shaped reinforced concrete buildings with variations on elastic columns configurations
Authors: Pudjisuryadi P , Lumantarna B , Arcan C J , Pratama H
Published: June 2023

Modified Partial Capacity Design (M-PCD) is an alternative design method for seismic-resistant structures. M-PCD adopts the partial side sway mechanism for its failure mechanism where beams and some columns are allowed to develop plastic hinges. This method uses two models for design. The first model simulates a small earthquake occurrence and is used to design beams and plastic columns. The second model simulates a larger earthquake occurrence and damages on the structure. The elastic columns are designed based on the superposition of internal forces from the first and second models, provided that the effects from gravity loads are considered only once. This study focuses on the application of M-PCD on six-story L-shaped reinforced concrete buildings with variations on elastic columns configurations. Nonlinear time history analyses are used to determine the buildings’ performance on two earthquake levels (EDRS and MCER) and two earthquake directions (0° and 45° rotated earthquake). The results show that the partial side sway mechanism is observed in most of the analyzed structures and drifts are within set boundaries.
Bond strength between reinforcement and High Volume Fly Ash-Self Compacting Concrete (HVFA-SCC)
Authors: Rohman R K , Kristiawan S A , Basuki A , Saifullah H A
Published: June 2023

This paper explains the bond strength between the reinforcing bar and High Volume Fly Ash-Self Compacting Concrete (HVFA-SCC). The bond strength is determined by a pull-out test on the concrete cube (200x200x200 mm) with a single steel bar centrally placed in the cube following the RILEM standard. The HVFA-SCC is proportioned with an inclusion of 50% fly ash by weight of the total binder. The concrete satisfies the flowability criteria of SCC and has the average concrete compressive strength of 38.8 MPa. The test result shows that an average bond strength of HVFA-SCC is 12.93 Mpa and 3.89 MPa for deformed and plain bars, respectively. The obtained bond strength of HVFA-SCC is compared with the bond strength of other concrete types found in the literature. It confirms that the HVFA-SCC bond strength is higher than normal concrete (NC), and comparable with geopolymer concrete (GC), HVFAC, and SCC.