bluuebunny/crossref_metadata_2025 huggingface dataset:
Delay induced stability switch in a mathematical model of CD8 T-cell response to SARS-CoV-2 mediated by receptor ACE2
Authors: Lv Jinlong , Ma Wanbiao
Published: April 2024

The pathogen SARS-CoV-2 binds to the receptor angiotensin-converting enzyme 2 (ACE2) of the target cells and then replicates itself through the host, eventually releasing free virus particles. After infection, the CD8 T-cell response is triggered and appears to play a critical role in the defense against virus infections. Infected cells and their activated CD8 T-cells can cause tissue damage. Here, we established a mathematical model of within-host SARS-CoV-2 infection that incorporates the receptor ACE2, the CD8 T-cell response, and the damaged tissues. According to this model, we can get the basic reproduction number R0 and the immune reproduction number R1. We provide the theoretical proof for the stability of the disease-free equilibrium, immune-inactivated equilibrium, and immune-activated equilibrium. Finally, our numerical simulations show that the time delay in CD8 T-cell production can induce complex dynamics such as stability switching. These results provide insights into the mechanisms of SARS-CoV-2 infection and may help in the development of effective drugs against COVID-19.
Tailoring the electrical and magneto-electric transport properties of ZnO films via Ti ion implantation
Authors: Pal Santanu , Das Amaresh , Basak Durga
Published: April 2024

A significant development toward semiconductor-based electronic devices is based on the electric and magneto-electric control of the transport properties of the charge carriers. This study unprecedentedly investigates the Ti implantation and thereafter the effect of structural defects on the electrical and magneto-electric transport properties of Ti-implanted RF-sputtered ZnO thin films. Theoretical stopping and range of ions in matter simulations along with the experimental structural and elemental studies reveal that Ti ion implantation generates a significant amount of oxygen vacancy (VO) defects apart from Ti-related impurities in post-implantation annealed films. The film implanted with 8 × 1015 ions/cm2 (TZO815) exhibits the lowest resistivity (4.68 × 10−3 Ω cm) and the highest carrier concentration (6.61 × 1020 cm−3) values. Resistivity measurements over a temperature range of 5-300K indicate semiconducting behavior for all the films implanted up to fluences of 5 × 1015 ions/cm2 identified with a grain boundary dominated thermally activated band, nearest neighbor hopping, and Mott and Efros–Shklovskii (ES) variable range hopping conduction mechanisms at various temperature intervals. Notably, the gradual decrease in both Mott and ES hopping ranges following Ti implantation indicates the formation of more localized states. Interestingly, the TZO815 film exhibits metal-semiconductor transition around 220 K, suggesting the formation of a degenerate band within the ZnO conduction band upon Ti implantation. Remarkably, the magnetoresistance results align with a semiempirical formula proposed by Khosla and Fischer, indicating that a negative magneto resistance in the TZO thin films is attributed to the spin-dependent scattering of conduction electrons by the localized magnetic moments induced mainly by the implantation induced VO defects.
Acoustic and optical plasmons excitation in double-channel AlGaN/GaN HEMT under asymmetric boundaries
Authors: Guo Hongyang , Yang Shengpeng , Zhang Ping , Xing Runxian , Yu Guohao , Wang Shaomeng , Gong Yubin
Published: April 2024

We have simulatively studied the electrical excitation of acoustic and optical plasmons in double-channel AlGaN/GaN high electron mobility transistors (HEMT) under asymmetric boundaries. By solving the self-consistent hydrodynamic model with Maxwell’s equations, it is found that the drift plasmons are excited in the bilayer 2DEGs under asymmetric boundaries. The oscillation intensity in a bilayer system is much stronger than that in a monolayer 2DEG system because of the simultaneous excitation of the fundamental and the second harmonic components. The fundamental component always corresponds to the acoustic plasmon, while the optical plasmon can be excited when it is resonant with the second harmonic of the acoustic plasmon. Because of the out-of-phase properties of the acoustic plasmons, their radiated power is limited by the current cancellation. On the other hand, as the optical plasmons are excited, the radiated powers are much higher than those of the single channel HEMT due to the in-phase currents generated in the double layers. The effects of different parameters such as gate lengths, 2DEG spacings, and electron concentrations on plasmon excitations and THz emissions of double-channel HEMTs are analyzed in detail. The numerical results provide a more powerful terahertz radiation mechanism in double-channel HEMT compared with the Dyakonov–Shur instability in traditional single-channel HEMT.
Analysis of generalized type-II progressively hybrid Lindley-exponential data and its modeling in physics, engineering, and management
Authors: Alotaibi Refah , Rezk Hoda , Elshahhat Ahmed
Published: April 2024

The life test is guaranteed to end at a predetermined time using a novel type-II generalized progressively hybrid censoring method that is investigated when the test participants’ lifetime model has a two-parameter Lindley-exponential (LndE) distribution. The LndE characteristics are estimated using Bayes and maximum likelihood inference techniques when the suggested censored data are present. By employing the normal approximation of each unknown quantity, the estimated confidence intervals are also constructed. Additionally, independent gamma density priors are used to generate the Bayesian estimators under symmetrical (squared error) loss. Since the likelihood function is formulated in a difficult manner, the Bayes estimators and their corresponding greatest posterior density intervals cannot be computed theoretically, but they may be evaluated using Markov-chain Monte Carlo algorithms. The most progressive design is then determined by applying four optimality criteria. Using Monte Carlo comparisons, the efficiency of the proposed estimating processes is evaluated, and some suggestions are made. In the end, the usefulness of the suggested methods that may be applied in practical situations is demonstrated by analyzing three distinct applications: physics, engineering, and management. When the experimenter’s primary concern is the test’s duration, the numerical findings revealed that the sampling strategy is adaptable and incredibly successful in finishing the experiment in a variety of realistic scenarios.
Analysis of wavy leading-edge noise reduction and source mechanism in rod-airfoil interactions
Authors: Yu Fu-Yang , Wan Zhen-Hua , Hu Ya-Sen , Sun De-Jun , Lu Xi-Yun
Published: April 2024

Inspired by the wings of owls and the tubercles present on humpback whales' flippers, leading-edge serrations have demonstrated the potential to mitigate airfoil–turbulence interaction noise. To deepen our understanding of the underlying mechanisms driving this noise reduction, we conducted compressible large-eddy simulations on a rod-airfoil configuration equipped with wavy leading edges (WLEs) of varying amplitudes. All tested serrations exhibited some degree of noise reduction, with the amplitude of the WLE exerting a significant influence on the overall noise reduction effect. Notably, the wavy airfoil with the largest amplitude demonstrated the most substantial noise reduction in the mid-frequency range, achieving a remarkable decrease in up to 2.2 dB in noise levels. Applying multi-process acoustic theory, we delved into sound production on surfaces and near-field structures responsible for generating noise sources. Our findings underscore a crucial mechanism contributing to noise reduction—the source cutoff effects manifested through the significant weakening of noise sources at hill regions along the serrations' surface. Stronger source cutoff effects were observed with larger WLE amplitudes. Furthermore, our study reveals that destructive relationships among sources also play a pivotal role in reducing flow noise. The reduction in mid-frequency noise results from a synergy of the source cutoff effect and destructive source relationships induced by WLEs, while the decrease in low-frequency noise primarily emanates from the source cutoff effect.
Experimental and numerical research on blended blade and end wall technique in a compressor cascade
Authors: Meng Tongtong , Li Xin , Zhou Ling , Ji Lucheng
Published: April 2024

In this paper, to explore the effects and mechanisms of the blended blade and end wall (BBEW) technique on corner separation control, two different BBEW configurations, including the side blended blade and end wall (S-BBEW) and full blended blade and end wall (F-BBEW), are studied and compared through experimental and numerical analyses. First, for a linear cascade, the S-BBEW and F-BBEW designs are carefully built. Then, both numerical simulations and experiments are conducted for each design, demonstrating a significant reduction in the loss coefficient. The results indicate that the S-BBEW is effective in the control of boundary layer development and delays the initial point of separation, especially at the design working condition. Moreover, the F-BBEW design nearly eliminates the corner separation by the control of both boundary layer development and secondary flow, which provides a higher performance improvement, especially at a large incidence angle.
Combined acoustic methods in monitoring the crack development in granite
Authors: Zhang Guokai , Li Haibo , Wang Mingyang , Wang Zhen , Deng Shuxin , Gao Fei , Zou Chunjiang
Published: April 2024

Detecting cracks of various sizes is crucial for monitoring and predicting rock failure. This study combines two acoustic methods—the passive acoustic emission (AE) and the active ultrasonic P-wave velocity to investigate the cracking process from initiation to propagation and coalescence of rocks containing pre-existing flaws, which simulate the intrinsic defects in natural rocks or rock masses, across different scales in three-dimensional space. The resultant AE activity is found sensitive to microcracks even in the early loading stage and can be divided into three stages: quiet, stable, and high growth periods. The positions of the microcracks can be obtained with the assistance of several AE sensors. It is also found that the P-wave velocity attenuation is more sensitive to macrocracks but less sensitive to microcracks. The results indicate that combining the AE and active ultrasonic-wave methods can provide comprehensive information to evaluate the damage levels and localize the internal cracks with multiple scales in the entire cracking process of rocks. The study also indicates the potential for predicting crack coalescence and failure based on the combination of these two nondestructive methods. In addition, the findings can also be applicable in the monitoring and prediction of failure in other brittle materials.
Slip topology of steady flows around a critical point: Taking the linear velocity field as an example
Authors: Zou Wennan , He Jian
Published: April 2024

The flow of viscous fluids is considered as the aggregation of the motion of fluid particles when the fluid is conceived to be made up by an infinite number of particles. As an alternative of this conventional model, fluid motion could be understood as the slip of fluid layers with a molecular scale over each other, where the slip structures of fluid and their associated small-scale motion are characterized by an axial-vector-valued differential 1-form, called the vortex field. In this paper, in the case of steady flows we define the swirling degree of the velocity field at a point, and further the swirl field of the steady flow, to study the slip topology of fluid or the local streamline pattern around the critical point. The linear velocity field in the right real Schur form is used to carry out detailed analyses around the isolated critical point. Theoretical deduction and numerical test unveil the connection between the swirling degree and the swirl field, greatly make clear the topological property of slip structures of fluid in steady flows, especially in three-dimensional space.
Interaction of the flow and flame dynamics of a line wildfire in the atmospheric wake flow of a ridge
Authors: Sun Yujia , Zheng Shu , Liu Chao
Published: April 2024

Understanding the flow and flame dynamics is important due to its relevance in wildfires, which become severe in recent years. The flow and flame dynamics of wildfire have been extensively studied on flat and inclined surface but are rarely studied under rough surface, such as the condition of a ridge or a hill, which is relevant for many of the wildfire scenarios in mountain areas. To investigate the interaction of wildfire with the wake flow over a ridge, this is the first study that uses a large-eddy simulation to model the flow and flame dynamics of a line fire located at the lee side of a ridge. The results show that the flame dynamics can be significantly influenced by the wake flow, and their interaction features cyclic four stages.
Experimental observations and modeling of the effect of wettability on immiscible viscous fingers at the Darcy scale
Authors: Beteta Alan , Sorbie Kenneth S. , McIver Katherine
Published: April 2024

In this work, we present a Darcy-scale study of immiscible unstable displacement in large (15 × 15 × 1 cm3) slabs of Bentheimer sandstone. Oil is displaced by water under two wetting conditions, a weakly water-wet system and a weakly oil-wet system (at two initial water saturations), with a viscosity ratio of μo/μw = 100. The system is directly visualized using x rays and the fluid distribution monitored throughout the displacement. Following a period of water flooding, the injection water is viscosified with glycerol to act as a pseudo tertiary polymer flood. The experiments are then modeled directly using numerical simulation applying a recently developed fractional flow approach, which has been shown to reproduce experimental immiscible fingering, before upscaling the results to the reservoir scale. From the observed results, we can conclude that typical wettability modification using crude oil aging may generate a wettability similar to that found in oil reservoirs, but this may still result in an exaggerated capillary dampening of the viscous fingers. However, as the system is scaled up in size to the field dimensions, viscous forces will dominate, and fingering will re-emerge due to the increase in the viscous/capillary force balance. But if the input relative permeabilities are constructed from an excessively capillary stabilized experiment, the shock front mobility of the fractional flow will still overestimate the stability of the system. Indeed, we derive the same water saturation above Swi for the three floods, but with different shock front mobilities.
Perceptions and attitudes of dental practitioners toward robotic dentistry and artificial intelligence in Saudi Arabia
Authors: Alzahrani Abdullah Ali H.
Published: April 2024

Robotic dentistry (RD) and artificial intelligence (AI) are gradually evolving and may become an integral part of dentistry. The purpose of this study is to assess the perceptions and attitudes of dental practitioners in Saudi Arabia toward the use of RD and AI in dentistry. A national dental survey using a pre-designed and validated perceptions and attitude electronic questionnaire was conducted. The mean scores, descriptive analysis, t-test, analysis of variance one-way test, and correlations between participants’ demographic characteristics and responses were used as appropriate. A total of 426 dental practitioners participated with a mean age of 35 ± 8.5 years. The overall questionnaire mean score was 51.12 ± 8.2, indicating a moderate level of participants’ perceptions and attitudes toward RD and AI. Demographic items including age, gender, job’s title/rank, qualification degree, and working experience significantly influenced participants’ perceptions and attitudes (p < 0.0001, p = 0.003, p < 0.0001, p < 0.0001, p < 0.0001). RD and AI applications in dentistry could support dentist’s provider best possible care to patients. An emphasis on updating courses related to RD dentistry in dental schools and an increasing number of required continuing education hours and workshops may also be advocated. Future research may focus on the quality and effect of implemented educational programs and guidelines to demonstrate the impact of Rd and AI models in dentistry practice.
Exploring wind curtailment effects and economic implications in the growing variable renewable energy penetration
Authors: Kim Dae-Young , Kim Bum-Suk
Published: April 2024

Several countries continue to invest in variable renewable energy (VRE) sources to replace fossil fuels and achieve a nationally determined contribution. Consequently, as the share of VRE generation in each country's power grid increases, its curtailment also increases. Current studies on VRE curtailment are based on a comparative analysis of statistical data collected from different countries. However, only a few studies present detailed results based on historical curtailment data collected from individual wind farms. This study analyzes the curtailment data collected for three wind farms over four years. The duration, curtailed output, and cost per curtailment were determined to be 200 min, 38 MWh, and $3.02k, respectively. Finally, the curtailment loss to wind farms caused by the increasing share of VRE generation in the power grid was estimated. The curtailed output and curtailment cost are estimated to increase by 1.3 GWh and $107.6k, respectively, when the share of VRE in the power grid increases by 1%. These findings can aid in identifying the curtailment experienced by wind farm operators and subsequent potential economic losses. Moreover, they can form the basis for establishing an efficient curtailment cost compensation system.
Evaluation and analysis of water-regulation value of ecosystem in Qinghai area of Qilian Mountain National Park, China
Authors: Zhang Ying , Meng Na , Shi Yan , Li Xiaoge
Published: April 2024

Context Water-regulation services significantly affect local social and economic development in the Qinghai area of Qilian Mountain National Park, China, and also affect the role of a ‘solid reservoir’ in China. Aim The value and change trend of water regulation was assessed through the evaluation and prediction of the water-regulation value of ecosystems. Methods InVEST water yield model and SVR model are used to evaluate and predict the water-regulation value of ecosystem in this study. Key results Grassland plays an important role in water regulation, although the area of forestland is not large, its water-regulation monetary value in 2020 accounted for 13.92% of the total evaluation value. From 2010 to 2020, the physical value of water regulation increased by 2.24% and the monetary value increased ~0.97% annually. In 2030, the amount of physical and monetary value of water regulation will be increased. Conclusion Grassland plays an important role in water regulation. It is necessary to strengthen the asset management of water regulation and optimise the ecological resources. Implications The study findings are utilised to enhance monitoring and establish ecological big-data platform, thereby elevating the quality of national park development management and decision-making services.
Reinforcement learning informs optimal treatment strategies to limit antibiotic resistance
Authors: Weaver Davis T. , King Eshan S. , Maltas Jeff , Scott Jacob G.
Published: April 2024

Antimicrobial resistance was estimated to be associated with 4.95 million deaths worldwide in 2019. It is possible to frame the antimicrobial resistance problem as a feedback-control problem. If we could optimize this feedback-control problem and translate our findings to the clinic, we could slow, prevent, or reverse the development of high-level drug resistance. Prior work on this topic has relied on systems where the exact dynamics and parameters were known a priori. In this study, we extend this work using a reinforcement learning (RL) approach capable of learning effective drug cycling policies in a system defined by empirically measured fitness landscapes. Crucially, we show that it is possible to learn effective drug cycling policies despite the problems of noisy, limited, or delayed measurement. Given access to a panel of 15

β

-lactam antibiotics with which to treat the simulated
Escherichia coli
population, we demonstrate that RL agents outperform two naive treatment paradigms at minimizing the population fitness over time. We also show that RL agents approach the performance of the optimal drug cycling policy. Even when stochastic noise is introduced to the measurements of population fitness, we show that RL agents are capable of maintaining evolving populations at lower growth rates compared to controls. We further tested our approach in arbitrary fitness landscapes of up to 1,024 genotypes. We show that minimization of population fitness using drug cycles is not limited by increasing genome size. Our work represents a proof-of-concept for using AI to control complex evolutionary processes.
Immune drivers of physiological and pathological pain
Authors: Jain Aakanksha , Hakim Sara , Woolf Clifford J.
Published: April 2024

Physiological pain serves as a warning of exposure to danger and prompts us to withdraw from noxious stimuli to prevent tissue damage. Pain can also alert us of an infection or organ dysfunction and aids in locating such malfunction. However, there are instances where pain is purely pathological, such as unresolved pain following an inflammation or injury to the nervous system, and this can be debilitating and persistent. We now appreciate that immune cells are integral to both physiological and pathological pain, and that pain, in consequence, is not strictly a neuronal phenomenon. Here, we discuss recent findings on how immune cells in the skin, nerve, dorsal root ganglia, and spinal cord interact with somatosensory neurons to mediate pain. We also discuss how both innate and adaptive immune cells, by releasing various ligands and mediators, contribute to the initiation, modulation, persistence, or resolution of various modalities of pain. Finally, we propose that the neuroimmune axis is an attractive target for pain treatment, but the challenges in objectively quantifying pain preclinically, variable sex differences in pain presentation, as well as adverse outcomes associated with immune system modulation, all need to be considered in the development of immunotherapies against pain.
Self-regulating CAR-T cells modulate cytokine release syndrome in adoptive T-cell therapy
Authors: Lin Meng-Yin , Nam Eunwoo , Shih Ryan M. , Shafer Amanda , Bouren Amber , Ayala Ceja Melanie , Harris Caitlin , Khericha Mobina , Vo Kenny H. , Kim Minsoo , Tseng Chi-Hong , Chen Yvonne Y.
Published: April 2024

Cytokine release syndrome (CRS) is a frequently observed side effect of chimeric antigen receptor (CAR)-T cell therapy. Here, we report self-regulating T cells that reduce CRS severity by secreting inhibitors of cytokines associated with CRS. With a humanized NSG-SGM3 mouse model, we show reduced CRS-related toxicity in mice treated with CAR-T cells secreting tocilizumab-derived single-chain variable fragment (Toci), yielding a safety profile superior to that of single-dose systemic tocilizumab administration. Unexpectedly, Toci-secreting CD19 CAR-T cells exhibit superior in vivo antitumor efficacy compared with conventional CD19 CAR-T cells. scRNA-seq analysis of immune cells recovered from tumor-bearing humanized mice revealed treatment with Toci-secreting CD19 CAR-T cells enriches for cytotoxic T cells while retaining memory T-cell phenotype, suggesting Toci secretion not only reduces toxicity but also significantly alters the overall T-cell composition. This approach of engineering T cells to self-regulate inflammatory cytokine production is a clinically compatible strategy with the potential to simultaneously enhance safety and efficacy of CAR-T cell therapy for cancer.
Experimental Investigation of Lee–Yang Criticality Using Non-Hermitian Quantum System
Authors: Lan 蓝 Ziheng 子桁 , Liu 刘 Wenquan 文权 , Wu 伍 Yang 旸 , Ye 叶 Xiangyu 翔宇 , Yang 杨 Zhesen 哲森 , Duan 段 Chang-Kui 昌奎 , Wang 王 Ya 亚 , Rong 荣 Xing 星
Published: April 2024

Lee–Yang theory clearly demonstrates where the phase transition of many-body systems occurs and the asymptotic behavior near the phase transition using the partition function under complex parameters. The complex parameters make the direct investigation of Lee–Yang theory in practical systems challenging. Here we construct a non-Hermitian quantum system that can correspond to the one-dimensional Ising model with imaginary parameters through the equality of partition functions. By adjusting the non-Hermitian parameter, we successfully obtain the partition function under different imaginary magnetic fields and observe the Lee–Yang zeros. We also observe the critical behavior of free energy in vicinity of Lee–Yang zero that is consistent with theoretical prediction. Our work provides a protocol to study Lee–Yang zeros of the one-dimensional Ising model using a single-qubit non-Hermitian system.
Plasmonic effect of metal nanoparticles on the photocatalytic properties of TiO2/rGO composite
Authors: Seliverstova Evgeniya , Serikov Timur , Nuraje Nurxat , Ibrayev Niyazbek , Sadykova Aigul , Amze Magzhan
Published: April 2024

A comparative study of the plasmon effect of Ag and Au nanoparticles on TiO2/rGO nanocomposite was carried out. The synthesis of Au and Ag nanoparticles was carried out by laser ablation. The morphology and structure of the nanocomposites were studied by EDA, HRTEM, XRD and Raman spectroscopy. It was shown that the absorption capacity of the nanocomposite material was increased in the visible range of the spectrum when Ag and Au nanoparticles were added to TiO2/rGO. This leads to an increase in their photocatalytic activity. The photocurrent generated by NC/Au 10−11 films is in 3.8 times and NC/Ag 10−12 is in 2 times higher compared to pure TiO2/rGO film. Similar results were obtained from experimental data on the dyes photodegradation. In the presence of plasmon nanoparticles a significant enhancement in the electrical properties of the TiO2/rGO nanocomposite was recorded. The charge carrier transfer resistance in nanocomposites was decreased by almost ∼7 times for NC/Au,10−11 and ∼4 times for NC/Ag,10−12 films compared to pure TiO2/rGO. In addition, for nanocomposites with Ag or Au nanoparticles, a decrease in the effective electron lifetime was observed. The data obtained allow us to conclude that plasmonic NPs have a synergistic effect in TiO2/rGO nanocomposites, which consists in modifying both their light-harvesting properties and charge-transport characteristics. The results obtained can be used for the design of materials with improved photocatalytic and optoelectronic characteristics.
Growth of curvature and perimeter of temperature patches in the 2D Boussinesq equations
Authors: Park Jaemin
Published: April 2024

In this paper, we construct an example of temperature patch solutions for the two-dimensional, incompressible Boussinesq system with kinematic viscosity such that both the curvature and perimeter grow to infinity over time. The presented example consists of two disjoint, simply connected patches. The rates of growth for both curvature and perimeter in this example are at least algebraic.
Innovative flight control explanation and demonstration: bridging theory and practice in secondary education
Authors: Wei Yajun , Chen Xiaotong , Luo Wanrong , Zou Qingsong , Zhang Xiaopan
Published: April 2024

How do airplanes turn, pitch, and roll? This fundamental question about airplane control captivates many pupils. Offering a comprehensible explanation to secondary school students is challenging due to the complex nature of fluid dynamics and mechanics. In this paper, we provide an accessible explanation of flight control principles, supported by carefully designed illustrations. Furthermore, we address the gap in educational resources by introducing a novel indoor demonstration apparatus. This design employs universal joints and remote-controlled model airplanes to visually demonstrate the principles of airplane control, particularly focusing on the maneuvers of turning, pitching, and rolling. This method is cost-effective, straightforward to implement, and offers students and aviation enthusiasts a highly intuitive and engaging learning experience.
Acoustic testing of the inverse-square law using the infrared signal of a remote control
Authors: Marín-Sepúlveda Camila F , Ortuño-Molina Santiago , Castro-Palacio Juan C , Monsoriu Juan A
Published: April 2024

In this work, the inverse-square law has been tested for the electromagnetic radiation in the infrared range. As a point-source, a TV remote control has been used. The intensities registered by a solar cell plugged to a speaker have been measured acoustically by recording the sound produced by the infrared pulses. The recorded audio is edited to find the intensities for different distances between the remote control and the solar cell. The results were fitted with a parametric function of the intensity inversely proportional to the distance square. A very good agreement was achieved.
How quickly does FLASH need to be delivered? A theoretical study of radiolytic oxygen depletion kinetics in tissues
Authors: Taylor Edward , Létourneau Daniel
Published: April 2024

Purpose. Radiation delivered over ultra-short timescales (‘FLASH’ radiotherapy) leads to a reduction in normal tissue toxicities for a range of tissues in the preclinical setting. Experiments have shown this reduction occurs for total delivery times less than a ‘critical’ time that varies by two orders of magnitude between brain (∼0.3 s) and skin (⪆10 s), and three orders of magnitude across different bowel experiments, from ∼0.01 to ⪆(1–10) s. Understanding the factors responsible for this broad variation may be important for translation of FLASH into the clinic and understanding the mechanisms behind FLASH. Methods. Assuming radiolytic oxygen depletion (ROD) to be the primary driver of FLASH effects, oxygen diffusion, consumption, and ROD were evaluated numerically for simulated tissues with pseudorandom vasculatures for a range of radiation delivery times, capillary densities, and oxygen consumption rates (OCR’s). The resulting time-dependent oxygen partial pressure distribution histograms were used to estimate cell survival in these tissues using the linear quadratic model, modified to incorporate oxygen-enhancement ratio effects. Results. Independent of the capillary density, there was a substantial increase in predicted cell survival when the total delivery time was less than the capillary oxygen tension (mmHg) divided by the OCR (expressed in units of mmHg/s), setting the critical delivery time for FLASH in simulated tissues. Using literature OCR values for different normal tissues, the predicted range of critical delivery times agreed well with experimental values for skin and brain and, modifying our model to allow for fluctuating perfusion, bowel. Conclusions. The broad three-orders-of-magnitude variation in critical irradiation delivery times observed in in vivo preclinical experiments can be accounted for by the ROD hypothesis and differences in the OCR amongst simulated normal tissues. Characterization of these may help guide future experiments and open the door to optimized tissue-specific clinical protocols.
Intrinsic rotation modulation by diffusive neutral particles in tokamaks
Authors: Brzozowski III R W , Stoltzfus-Dueck T
Published: April 2024

The modulated transport model, a model kinetic ion transport equation for the pedestal and scrape-off layer (SOL), is generalized to self-consistently include effects of a single neutral particle species. The neutrals contribute additional transport terms, modifying the

v

∥

-dependent orbit-averaged ion diffusivities of the original work and the resulting predicted intrinsic rotation of the ions. After making simplifying assumptions of the neutral transport, in particular taking the continuous transport limit via a short charge-exchange step expansion, we derive relatively simple analytic expressions that capture the diffusive neutral physics. Within the scope of the model’s validity, the neutral-driven intrinsic rotation can compete with the turbulence-driven intrinsic rotation. However, for physically motivated parameters, the neutral-driven intrinsic rotation appears negligible, either on a term-by-term basis or due to a strong cancellation between the neutral-driven momentum diffusion and pinch terms. It appears that a treatment containing finite charge-exchange steps is necessary to capture neutral transport of strong flow momentum into the confined region from the SOL.
Static performance prediction of long-pulse negative ion based neutral beam injection experiment
Authors: Li Yang , Hu Chundong , Zhao Yuanzhe , Gu Yu , Cui Qinglong , Xie Yahong
Published: April 2024

The mission of negative ion-based neutral beam injection (NNBI) is to conduct experiments with pulses lasting thousands of seconds. It is crucial to develop a simplified physical calculation model for the long-pulse negative ion source in the current NNBI device. This model will be used to evaluate the advantages and disadvantages of the selected parameters prior to the experiment, and to assist in adjusting and establishing the experimental parameters for the long-pulse ion source experiment. This paper presents the development of a static performance prediction model using a back propagation neural network. The model assesses the yield of negative hydrogen ions and the quantity of electrons in the ion source under specific parameter conditions, utilizing various experimental parameters as input. The experimental data used for this model are derived from historical data generated during the operation of the 2022 NNBI experiment. The test results indicate that under the current optimal hyperparameter condition, the prediction accuracy of H− ion current (I_H−) is 80.84%, and the prediction accuracy of extraction grid electronic current (I_EG) is 77.57%. This can effectively prevent invalid shots, accurately assess the advantages and disadvantages of the input parameters, and enhance the performance of the long-pulse NNBI device.
On double-layer and reverse discharge creation during long positive voltage pulses in a bipolar HiPIMS discharge
Authors: Pajdarová A D , Kozák T , Tölg T , Čapek J
Published: April 2024

Time-resolved Langmuir probe diagnostics at the discharge centerline and at three distances from the target (

35

mm

,

60

mm

, and

100

mm

) was carried out during long positive voltage pulses (a duration of

500

μ
s

and a preset positive voltage of

100

V

) in bipolar high-power impulse magnetron sputtering of a Ti target (a diameter of

100

mm

) using an unbalanced magnetron. Fast-camera spectroscopy imaging recorded light emission from Ar and Ti atoms and singly charged ions during positive voltage pulses. It was found that during the long positive voltage pulse, the floating and the plasma potentials suddenly decrease, which is accompanied by the presence of anode light located on the discharge centerline between the target center and the magnetic null of the magnetron’s magnetic field. These light patterns are related to the ignition of a reverse discharge, which leads to the subsequent rise in the plasma and the floating potentials. The reversed discharge is burning up to the end of the positive voltage pulse, but the plasma and floating potentials have lower values than the values from the initial part of the positive voltage pulse. Secondary electron emission induced by the impinging Ar+ ions to the grounded surfaces in the vicinity of the discharge plasma together with the mirror configuration of the magnetron magnetic field are identified as the probable causes of the charge double-layer structure formation in front of the target and the ignition of the reverse discharge.
The Kondo scaling for spin thermocurrent in strongly correlated electron systems
Authors: Li ZhenHua , Zeng YuRong , Cheng YongXi , Zheng Xiao , Wei JianHua , Luo Hong-Gang , Yan YiJing
Published: April 2024

One of the most important feature in the Kondo physics is the universal scaling behavior. In this study, we analyze the transport behavior of the spin thermocurrent driven by a small temperature bias and under a weak magnetic field. We conclude that the spin thermocurrent exhibits a universal scaling behavior, similar to the spin susceptibility. The validity of our conclusion is also checked by using the numerically exact hierarchical equations of motion approach. From our fitting result of the scaling function, it is found that the Kondo temperature can be determined by the maximum of the spin thermocurrent at

T

/

T
K

=
0.383

.
A minimalist approach to 3D photoemission orbital tomography: algorithms and data requirements
Authors: Dinh Thi Lan , Jansen G S Matthijs , Luke D Russell , Bennecke Wiebke , Mathias Stefan
Published: April 2024

Photoemission orbital tomography provides direct access from laboratory measurements to the real-space molecular orbitals of well-ordered organic semiconductor layers. Specifically, the application of phase retrieval algorithms to photon-energy- and angle-resolved photoemission data enables the direct reconstruction of full 3D molecular orbitals without the need for simulations using density functional theory or the like. However, until now this procedure has remained challenging due to the need for densely-sampled, well-calibrated 3D photoemission patterns. Here, we present an iterative projection algorithm that completely eliminates this challenge: for the benchmark case of the pentacene frontier orbitals, we demonstrate the reconstruction of the full orbital based on a dataset containing only four simulated photoemission momentum measurements. We discuss the algorithm performance, sampling requirements with respect to the photon energy, optimal measurement strategies, and the accuracy of orbital images that can be achieved.
A view of solitary wave solutions to the fractional DNA Peyrard-Bishop equation via a new approach
Authors: Özkan Ayten
Published: April 2024

In this study, the fractional impacts of the beta derivative and M-truncated derivative are examined on the DNA Peyrard-Bishop dynamic model equation. To obtain solitary wave solutions for the model, the Sardar sub-equation approach is utilized. For a stronger comprehension of the model, the acquired solutions are graphically illustrated together with the fractional impacts of the beta and M-truncated derivatives. In addition to being simple and not needing any complicated computations, the approach has the benefit of getting accurate results.
Robust 3D coordinate transformation based on genetic algorithm intelligent weighting
Authors: Zhang QiuYu , He XiaoYe , Wang Wei , Wu EnChen , Li Xiao , Ding Ting
Published: April 2024

In order to improve the solution quality of 3D coordinate transformation parameters, a robust optimization model is obtained by integrating the 3D coordinate transformation model within the overall framework of the genetic algorithm in this paper. The minimum of the weighted sum of squares of the point residuals of the common points is taken as the objective function for optimization, and the parallel search is started from the initial population, and the updating process of the solution set is used to generate new and better individuals, and the adaptive weight combination corresponding to the optimum of the fitness function is obtained at the end of the generation iteration. The generated simulated data and measured data were analyzed using the Hefei Light Source tunnel control network as an application scenario. The results show that the method in this paper can automatically reduce the influence of low-quality data on the model, and compared with the two robust conversion models of IGG III iterative weighting, the method in this paper is not affected by the empirical parameters in determining the weight combinations and the weighted sum of squares of the residuals of the solved points are smaller, so it can effectively improve the quality of the solved conversion parameters.
Adaptive residual convolutional neural network for compressive strength prediction of energetic materials using SEM images
Authors: Song Lei , Yin Aijun , Chen Shuhui , Long Zhendong
Published: April 2024

The microstructure of materials has a great influence on the macroscopic mechanical properties of materials, and the relationship between them is of great significance to the design of materials. With the development of artificial intelligence and deep learning, many researchers have used convolutional neural networks (CNN) to correlate microscopic images with material properties, and achieved good results. However, for different types of material performance prediction tasks and datasets of different sizes, researchers need to design a special CNN network structure, and the adjustment steps of network structure parameters are cumbersome and time consuming. In this paper, an adaptive residual convolutional neural network with variable depth and width is proposed. We take the prediction error of the test dataset of the specific material performance prediction task as the evaluation index, and adaptively adjusts the network structure based on simulated annealing algorithm to find the best network structure. Finally, it is verified on the dataset composed of scanning electron microscopy (SEM) images and compressive strength of polymer explosive materials. Mean absolute percentage error (MAPE) of our model is 1.3% and the goodness of fit

(
R

2

) is 0.943. Further, we use Grad-CAM to explore the correlation between material microstructure and material properties.
On the data assimilation of initial distribution for 2-dimensional shallow-water equation model
Authors: Zhang Hui , Liu Jijun
Published: April 2024

The utilization of data assimilation (DA) techniques is prevalent in marine meteorology for the purpose of estimating the complete state of the system. This is done to address the practical limitations associated with measurement data, which can only be specified at finite number of discrete points within a limited domain. We develop an efficient DA algorithm to reconstruct the initial state of the shallow-water equations (SWE) within a 2-dimensional rectangular domain using sparse spatial measurement data. Our algorithm takes into account both the complete Coriolis force and the ocean bottom topography in the SWE model, resulting in accurate recovery of the initial status. After establishing the uniqueness of the solution to the nonlinear SWE with appropriate boundary conditions, we proceed to establish the conservation laws for the suitably defined energy quantity for this traveling wave system. This generalization of the known conservation laws for the simplified SWE system which ignores the Coriolis force and topography, allows us to reveal the influence of nonconstant sea floor topography on wave propagation. In order to restore the initial state through the minimization of a cost functional using DA techniques, we proceed by deriving the adjoint problem for our iteration process. Additionally, we establish a discrete scheme for the governing equations in the Arakawa C-grid framework, from which we rigorously derive the error associated with energy conservation in discrete form. The numerical implementations are also provided to validate our proposed scheme through the verification of energy conservation and the reconstruction effect of the initial state for various configurations.
Traveling wave solution for a nonlocal Belousov-Zhabotinskii reaction-diffusion system
Authors: Chang Meng-Xue , Han Bang-Sheng , Yang Han
Published: April 2024

We consider a Belousov-Zhabotinskii reaction-diffusion system with nonlocal effects and study the existence of traveling wave solutions. By constructing appropriate super- and sub-solutions and using Schauder’s fixed point theorem, we show that there is a critical speed c
* > 0 such that when the wave speed c > c
*, there exists a traveling wave solution connecting (0, 0) to a positive steady-state, while there is no traveling wave solution when c < c
*. Moreover, we also examine a special case where ϕ
1(x) is the Dirac function, and demonstrate the existence of the traveling wave solution connecting the equilibria (0, 0) and (1, 1) for c > c
*, whereas the traveling wave solution does not exist when c < c
*. Finally, the long-time behavior of the solution is investigated through numerical simulation and theoretical analysis, and it is found that the choice of kernel functions and the setting of initial value conditions play a crucial role.
Effect of annealing on the electrical resistivity of Kondo lattice CeRh2Ga2
Authors: Anand V K , Adroja D T , Aarti  , Bhattacharyya A , Lake B
Published: April 2024

CeRh2Ga2, which crystallizes in CaBe2Ge2-type primitive tetragonal structure (space group P4/nmm), is known to exhibit Kondo lattice heavy fermion behavior and is proposed to be a potential candidate for Weyl-Kondo semimetal phase. Here we examine the effect of annealing, particularly on the electrical resistivity of polycrystalline CeRh2Ga2. A comparative study of the powder x-ray diffraction (XRD), magnetic susceptibility χ(T), heat capacity C
p(T) and electrical resistivity ρ(T) data of both as-arc-melted and annealed CeRh2Ga2 samples are presented. The XRD patterns of both as-arc-melted and annealed samples look similar. No marked effect of annealing could be clearly seen in the temperature dependences of χ and C
p data. However, the effect of annealing is clearly manifested in the T dependence of ρ, particlularly at low temperatures. At low-T the ρ(T) data of as-arc-melted CeRh2Ga2 follow a T
2 temperature dependence (Fermi-liquid feature), whereas the ρ(T) data of annealed CeRh2Ga2 exhibit an upturn (semimetal-like feature).
Theoretical triple differential cross sections for ionization of N
2 and CH
4 molecules by electron impact
Authors: Mondal M , Mandal B , Haque A , Purkait K , Purkait M
Published: April 2024

We present the angular distribution of electron emission by calculating the triple differential cross sections for (e, 2e) process on N
2 and CH
4 by using the three-body formalism of molecular first Born approximation (MFBA), two-Coulomb wave (M2CW), and three-Coulomb wave (M3CW) models, respectively. In these models, a Coulomb distorted wave is considered for the motion of the incident electron. We have considered the continuum-continuum correlation effect by choosing the final state as the three-Coulomb and two-Coulomb wave functions in M3CW and M2CW models, whereas the ejected electron is affected by a single centre field of the target in the MFBA model. In the M2CW model, the interaction between scattered electron-residual target ion has been described as a plane wave. The distinguishing feature among the three models has been noted in the TDCS as a strong binary peak with and without a recoil peak for several electron emission energies at fixed scattering angle. In the case of N
2 molecule, the TDCS shows oscillatory behaviour with the variation of the electron emission angle. The positions of the binary peak obtained by our theoretical models are well established by the experimental findings, but a large deviation is found in the region of the recoil peak. The contributions of TDCS for different molecular orbitals of the molecules to the spectrum of angular distributions at different electron emission energies have also been analyzed. Finally, a comparison is made with the measurement in coplanar asymmetry geometry. Overall, good agreement was found between experiments and M3CW theory.