bluuebunny/crossref_metadata_2025_split huggingface dataset:
High-dose femtosecond-scale gamma-ray beams for radiobiological applications
Authors: McAnespie C A , Streeter M J V , Rankin M , Chaudhary P , McMahon S J , Prise K M , Sarri G 
Published: March 2022

Abstract

Objective. In the irradiation of living tissue, the fundamental physical processes involved in radical production typically occur on a timescale of a few femtoseconds. A detailed understanding of these phenomena has thus far been limited by the relatively long duration of the radiation sources employed, extending well beyond the timescales for radical generation and evolution. Approach. Here, we propose a femtosecond-scale photon source, based on inverse Compton scattering of laser-plasma accelerated electron beams in the field of a second scattering laser pulse. Main results. Detailed numerical modelling indicates that existing laser facilities can provide ultra-short and high-flux MeV-scale photon beams, able to deposit doses tuneable from a fraction of Gy up to a few Gy per pulse, resulting in dose rates exceeding 1013 Gy/s. Significance. We envisage that such a source will represent a unique tool for time-resolved radiobiological experiments, with the prospect of further advancing radio-therapeutic techniques.
Development of a high-resolution, high-speed impact piezoelectric actuator using cross-frequency band method
Authors: Li Chen , Li Ruijun , Zhao Mingfei , Wang Ya , Wei Yongqing , Huang Qiangxian , Pan Qiaosheng 
Published: March 2022

Abstract
A novel impact piezoelectric actuator is proposed in this paper to achieve cross-scale driving, which can realise high resolution and high speed. The piezoelectric actuator is mainly composed of four diamond-shaped flexible hinges, which can consider a certain stiffness and flexibility. The operating principle of the piezoelectric actuator is introduced. The actuator is excited by two sinusoidal waves with a frequency ratio of 1:2 to achieve impact drive at quasi-static state. The appropriate structural parameters are obtained by simulation. The actuator is designed to make the frequency ratio of first and second vibration modes 1:2, which can achieve impact drive at resonant state. The prototype is fabricated, and the characteristics are tested. The measured resonant frequency ratio is consistent with the simulated value. Experimental results show that when the prototype works at quasi-static state, the resolution is 37 nm with driving voltages of 12 Vp-p; at resonant state, the no-load maximum speed is 125.43 mm s−1 and the maximum load is 0.5 N when the driving frequency and voltages are 1.95 kHz, 40 Vp-p and 3.90 kHz, 160 Vp-p, respectively. The proposed actuator can be used for precision positioning and can improve the accuracy and the efficiency of processing instruments.
High critical current solution derived YBa2Cu3O7 films grown on sapphire
Authors: Pop C , Barusco P , Vlad R , Queralto A , Gupta K , Almog B , Saraf A , Deutscher G , Granados X , Puig T , Obradors X 
Published: March 2022

Abstract
Superconducting fault current limiters (SFCLs) are very attractive devices which require to increase its robustness against the destructive hot spots. The use of sapphire substrates to grow YBa2Cu3O7 (YBCO) films is a very attractive approach due to its high thermal conductivity. This article reports the growth of microcrack-free, epitaxial YBCO layers by chemical solution deposition (CSD) on Ce1−x
Zr
x
O2 (CZO)/yttrium-stabilized zirconia/r-cut barely polished sapphire (BPS) substrates which can be produced in long lengths at low cost. The surface quality of the r-cut sapphire and its role on the epitaxy of CZO and YBCO layers is discussed. The issue of the microcrack generation in YBCO layers is investigated in relation to the film thickness, the growth process and the oxygenation annealing step. We demonstrate that microcracks formation is related to the in-plane tensile stress generated during the oxygenation step instead of the differential thermal expansion effects and thus it can be minimized through an adapted oxygenation process. We have shown that CSD growth of YBCO films with thicknesses up to 400 nm and attractive superconducting properties (J
C ∼ 1.9 MA cm−2 at 77 K) can be achieved on BPS substrates which can be used at moderate cost for SFCL devices.
Quantum biology. π–π entanglement signatures in protein-DNA interactions
Authors: D’Acunto Mario 
Published: March 2022

AbstractThe biological functions of DNA are carried out by individual proteins that interact with specific sequences along the DNA in order to prime the molecular processes required by the cellular metabolism. Protein-DNA interactions include DNA replication, gene expression and its regulation, DNA repair, DNA restriction and modification by endonucleases, generally classified as enzymatic functions, or transcription factors functions. To find specific binding target sequences and achieve their aims, in less than one second proteins operate in symbiosis with a crowded cellular environment, identifying extremely small cognate sequences along the DNA chain, which range from 15–20 bps for repressors to 4–6 bps for restriction enzymes. In a previous work, we proposed that the extraordinary ability of proteins to identify consensus sequences on DNA in a short time appears to be dependent on specific quantum signatures such as the entanglement ofπ–πelectrons between DNA nucleotides and protein amino acids, where the couple ofπelectrons function as a radical pair, oneπelectron is located on a specific site of sequence to be identified and the other one performs a quantum walk to identify possible sites of consensus sequence. In this paper, we use the restriction endonucleases enzymes, EcoRV and EcoRI as a case study. These enzymes are able to recognize 3′-GATACT-5′ or 3′-GAATCT-5′ sequences, respectively. We exploit the analogy of a coin operator with a Bloch sphere to demonstrate that the entanglement betweenπ–πelectrons generated at the contacts on specific GA dimers between proteins and DNA relies on the spin of the electrons that form an initial singlet state. The latter is a maximally entangled state so that the identification of specific nucleotides is associated with the formation of singlet states. On the other hand, during the identification of subsequent GA dimers, the spin–orbit interaction on walkingπelectron induces triplet transitions so that singlet–triplet transitions should manifest an experimentally measurable effect. We propose that the possible experimental evidence of entanglement betweenπ–πelectrons may be due to the phosphorescence signal correspondence to triplet decay processes.
Transmission electromagnetic beam splitter based on double-sided all dielectric microstructure
Authors: Wei Hongling , Cui Fuyi , Guo Weigang , Wu Yinglai 
Published: March 2022

Abstract
We propose a transmission type dual beam splitter based on all-dielectric encoded metasurface. In order to improve the efficiency of the device, we propose to construct the coding metasurface using double-sided all-dielectric cylindrical cell structure. Based on the electromagnetic dipole resonance characteristics of the all-dielectric resonator, two all-dielectric elements with transmission phase difference π were obtained, and 1-bit coded metasurface was constructed to achieve beam splitting characteristics of incident waves. Based on the finite integral method, we numerically simulate the far-field scattering characteristics of coded metasurface beam splitter. It is found that the number of digital repeats of coding unit particles has a great influence on beam splitting when constructing coding metasurface due to the coupling effect between particles. The energy ratio of double beam splitting can be continuously regulated by changing the incident angle. The dual-beam splitter we designed also has broadband characteristics.
Novel ELC-like and Z-shaped plasmonic waveguides to reach ultra-strong field confinements
Authors: Aziz Asad 
Published: March 2022

Abstract
In this paper, two novel waveguides with ELC like-shaped and Z-shaped grooves have been proposed to achieve highly efficient and strongly confined spoof surface plasmon polaritons (SSPPs) propagation. Low-dispersion bands can be realized by such structures with tight field confinement of SSPPs, resulting in size miniaturization of the proposed waveguides. Specifically, our method yields deep physical insight into the effect that the geometrically induced modifications of the supporting structure has on the dispersion properties and field confinement capabilities of SSPPs. In comparison, SSPP waveguide results presented in Aziz (2021 Results Opt.
5 100116) are given which is regarded to have stronger SSPPs field confinement as compared to previously reported different grooves shapes based SSPP waveguides. It is found that the dispersion and waveguide propagation characteristics can be directly manipulated by varying the geometrical parameters of the horizontal and slanted slits of Z-shaped and ELC-like shaped plasmonic waveguides without increasing the lateral dimension of the waveguides. Based on this waveguiding scheme, the proposed waveguides exhibit much lower asymptotic frequency of the dispersion relation and even tighter SSPPs field confinement than I-shaped plasmonic waveguide. Then, broadband transitions with a tapered metallic strip and an array of graded height ELC-like and Z-shaped units with good impedance matching and high mode conversion efficiency are designed. Fully controlled field enhancement functionality has been performed, by using such metamaterial particles in the form of grooves, decorated in SSPP waveguide. Simulated results have demonstrated that the proposed SSPP waveguides have much stronger field confinement than the highly efficient I-shaped grooves based SSPP waveguide. The proposed waveguides can be a significant contribution towards the advancement of plasmonic functional devices and integrated circuits in microwave frequencies.
Intracortical microstimulation pulse waveform and frequency recruits distinct spatiotemporal patterns of cortical neuron and neuropil activation
Authors: Stieger Kevin C , Eles James R , Ludwig Kip A , Kozai Takashi D Y 
Published: March 2022

Abstract

Objective. Neural prosthetics often use intracortical microstimulation (ICMS) for sensory restoration. To restore natural and functional feedback, we must first understand how stimulation parameters influence the recruitment of neural populations. ICMS waveform asymmetry modulates the spatial activation of neurons around an electrode at 10 Hz; however, it is unclear how asymmetry may differentially modulate population activity at frequencies typically employed in the clinic (e.g. 100 Hz). We hypothesized that stimulation waveform asymmetry would differentially modulate preferential activation of certain neural populations, and the differential population activity would be frequency-dependent. Approach. We quantified how asymmetric stimulation waveforms delivered at 10 or 100 Hz for 30 s modulated spatiotemporal activity of cortical layer II/III pyramidal neurons using in vivo two-photon and mesoscale calcium imaging in anesthetized mice. Asymmetry is defined in terms of the ratio of the duration of the leading phase to the duration of the return phase of charge-balanced cathodal- and anodal-first waveforms (i.e. longer leading phase relative to return has larger asymmetry). Main results. Neurons within 40–60 µm of the electrode display stable stimulation-induced activity indicative of direct activation, which was independent of waveform asymmetry. The stability of 72% of activated neurons and the preferential activation of 20%–90% of neurons depended on waveform asymmetry. Additionally, this asymmetry-dependent activation of different neural populations was associated with differential progression of population activity. Specifically, neural activity tended to increase over time during 10 Hz stimulation for some waveforms, whereas activity remained at the same level throughout stimulation for other waveforms. During 100 Hz stimulation, neural activity decreased over time for all waveforms, but decreased more for the waveforms that resulted in increasing neural activity during 10 Hz stimulation. Significance. These data demonstrate that at frequencies commonly used for sensory restoration, stimulation waveform alters the pattern of activation of different but overlapping populations of excitatory neurons. The impact of these waveform specific responses on the activation of different subtypes of neurons as well as sensory perception merits further investigation.
Reaching the superscattering regime with BIC physics
Authors: Canós Valero Adrià , Shamkhi Hadi K. , Kupriianov Anton S. , Tuz Vladimir R. , Bobrovs Vjaceslavs , Kivshar Yuri S. , Shalin Alexander S. 
Published: March 2022

Abstract
We uncover a novel mechanism of superscattering from subwavelength resonators linked to the physics of bound states in the continuum (BICs). Enhanced scattering occurs due to constructive interference within the Friedrich-Wintgen mechanism of interfering resonances. Through this process, the scattering cross section of a single resonance can exceed the currently established limit. We develop a general non-Hermitian model to describe interfering resonances of quasi-normal modes, and study subwavelength dielectric nonspherical resonators exhibiting avoided crossing resonances and quasi-BIC states. Our results reveal novel physics of non-Hermitian systems suggesting important applications for metadevices.
Comment on ‘From the Paris Agreement to corporate climate commitments: evaluation of seven methods for setting “science-based” emission targets’
Authors: Chang Andres , Farsan Alexander , Carrillo Pineda Alberto , Cummis Cynthia , Weber Chris 
Published: March 2022

Abstract
A study from Bjørn et al (2021) suggests that methods to allocate emissions to companies proportionally to their economic growth are consistent with equity-related principles and are effective at conserving a global emissions budget while the science based targets initiative’s (SBTi’s) absolute contraction approach (ACA) fulfills neither qualification. Here we identify four areas of concern with the study and propose a more comprehensive approach to science based targets (SBT) method evaluation. We respond that first, the authors’ method characterization does not differentiate between the emissions allocation that occurs in mitigation scenarios and that which is normatively caused by method formulae, and it misinterprets the drivers of emissions allocation in scenarios. Second, we note that the authors evaluate a method formula for ACA that does not match its use by the SBTi. Third, we acknowledge that allocating emissions based on economic growth can yield incoherent results by comparison to published climate change mitigation scenarios and suggest the authors also evaluate whether methods are effective at conserving sub-global emissions budgets. Fourth, we observe that although the study is framed as an evaluation of SBT methods, it relies almost entirely on assessments of one characteristic. We conclude by proposing a set of principles that should be met by effective SBT methods and a high-level assessment of SBT methods against these principles.
Reply to Comment on ‘From the Paris Agreement to corporate climate commitments: evaluation of seven methods for setting “science-based” emission targets’
Authors: Bjørn Anders , Lloyd Shannon , Matthews Damon 
Published: March 2022

Abstract
The Science Based Targets initiative has published a Comment to our study (Bjørn et al 2021 Environ. Res. Lett.
16 054019). We see the Comment as an important step towards addressing our study’s call for more systematic presentation of methods for setting science-based targets and increased transparency behind the initiative’s method recommendations. We also agree with some of the Comment’s points of criticism of our study and the related nuances introduced. Yet, we find other points to be inaccurate or misdirected. Here, we reply to the Comment by clarifying misunderstandings on our study’s aims, providing additional methodological details, and elaborating on our perspectives.
Self-thinning forest understoreys reduce wildfire risk, even in a warming climate
Authors: Zylstra Philip J , Bradshaw S Don , Lindenmayer David B 
Published: March 2022

Abstract
As climatic changes continue to drive increases in the frequency and severity of forest fires, it is critical to understand all of the factors influencing the risk of forest fire. Using a spatial dataset of areas burnt over a 65 year period in a 528 343 ha study area, we examined three possible drivers of flammability dynamics. These were: that forests became more flammable as fine biomass (fuel) returned following disturbance (H1), that disturbance increased flammability by initiating dense understorey growth that later self-thinned (H2), and that climatic effects were more important than either of these internal dynamics (H3). We found that forests were unlikely to burn for a short ‘young’ period (5–7 years) following fire, very likely to burn as the regrowing understorey became taller and denser (regrowth period), then after a total post-disturbance period of 43–56 years (young + regrowth periods), fire became unlikely and continued to decrease in likelihood (mature period). This trend did not change as the climate warmed, although increases in synoptic variability (mean changes in synoptic systems per season) had a pronounced effect on wildfire likelihood overall. Young forest and regrowth forest became increasingly likely to burn in years of greater synoptic variability and the time taken for forests to mature increased, but in years with the most severe synoptic variability, mature forests were the least likely to burn. Our findings offer an explanation for fire behaviour in numerous long-term studies in diverse forest types globally and indicate that, even in the face of a warming climate, ‘ecologically-cooperative’ approaches may be employed that reinforce rather than disrupt natural ecological controls on forest fire. These range from traditional indigenous fire knowledge, to modern targeting of suppression resources to capitalise on the benefits of self-thinning, and minimise the extent of dense regrowth in the landscape.
Study of synthesis temperature effect on β-NaGdF4: Yb3+, Er3+ upconversion luminescence efficiency and decay time using maximum entropy method
Authors: Pominova Daria , Romanishkin Igor , Proydakova Vera , Kuznetsov Sergei , Grachev Pavel , Ryabova Anastasia , Tabachkova Natalya , Fedorov Pavel , Loschenov Victor 
Published: March 2022

Abstract
Upconversion materials have several advantages for many applications due to their great potential in converting infrared light to visible. For practical use, it is necessary to achieve high intensity of UC luminescence, so the studies of the optimal synthesis parameters for upconversion nanoparticles are still going on. In the present work, we analyzed the synthesis temperature effect on the efficiency and luminescence decay of β-NaGd0.78Yb0.20Er0.02F4 (15–25 nm) upconversion nanoparticles with hexagonal crystal structure synthesized by anhydrous solvothermal technique. The synthesis temperature was varied in the 290 °C–320 °C range. The synthesis temperature was shown to have a significant influence on the upconversion luminescence efficiency and decay time. The coherent scattering domain linearly depended on the synthesis temperature and was in the range 13.1–22.3 nm, while the efficiency of the upconversion luminescence increases exponentially from 0.02 to 0.10% under 1 W cm−2 excitation. For a fundamental analysis of the reasons for the upconversion luminescence intensity dependence on the synthesis temperature, it was proposed to use the maximum entropy method for luminescence decay kinetics processing. This method does not require a preliminary setting of the number of exponents and, due to this, makes it possible to estimate additional components in the luminescence decay kinetics, which are attributed to different populations of rare-earth ions in different conditions. Two components in the green luminescence and one component in the red luminescence decay kinetics were revealed for nanoparticles prepared at 290 °C–300 °C. An intense short and a weak long component in green luminescence decay kinetics could be associated with two different populations of ions in the surface quenching layer and the crystal core volume. With an increase in the synthesis temperature, the second component disappears, and the decay time increases due to an increase in the number of ions in the crystal core volume and a more uniform distribution of dopants.
Axial effect analysis of relativistic electron beam propagation in vacuum
Authors: WANG Xi , HAO Jianhong , ZHANG Fang , ZHAO Qiang , FAN Jieqing , XUE Bixi , GAO Lei , CHAI Chenrui , DONG Zhiwei 
Published: March 2022

Abstract
In geostationary orbits and other quasi-vacuum environments, relativistic electron beams are affected by the initial emittance and space charge effects during the propagation process, resulting in beam quality degradation. Furthermore, axial energy distribution change in the beam and the axial transient electromagnetic effect caused by current changes in the head and tail regions of the beam also cause the beam to expand and affect its quality. In this study, the particle-in-cell method was used to construct a long-range propagation model of a relativistic electron beam in a vacuum environment. By calculating and simulating the axial energy distribution of the beam and the changes in the transient electromagnetic field, the axial effect during the propagation process was analyzed, and the parameter change law of the effective propagation of the beam was explored. This provided a theoretical reference for a more accurate assessment of the beam quality during propagation.
The application of a helicon plasma source in reactive sputter deposition of tungsten nitride thin films
Authors: YANG Yan , JI Peiyu , LI Maoyang , YU Yaowei , HUANG Jianjun , YU Bin , WU Xuemei , HUANG Tianyuan 
Published: March 2022

Abstract
A reactive helicon wave plasma (HWP) sputtering method is used for the deposition of tungsten nitride (WN
x
) thin films. N2 is introduced downstream in the diffusion chamber. The impacts of N2 on the Ar-HWP parameters, such as ion energy distribution functions (IEDFs), electron energy probability functions (EEPFs), electron temperature (T
e) and density (n
e), are investigated. With the addition of N2, a decrease in electron density is observed due to the dissociative recombination of electrons with

N

2

+

.

The similar IEDF curves of Ar+ and N2
+ indicate that the majority of

N

2

+

stems from the charge transfer in the collision between Ar+ and N2. Moreover, due to the collisions between electrons and N2 ions, EEPFs show a relatively lower T
e with a depletion in the high-energy tail. With increasing negative bias from 50 to 200 V, a phase transition from hexagonal WN to fcc-WN0.5 is observed, together with an increase in the deposition rate and roughness.