bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dose mimicking based strategies for online adaptive proton therapy of head and neck cancer
Authors: Borderias-Villarroel E , Fredriksson A , Cvilic S , Di Perri D , Longton E , Pierrard J , Geets X , Sterpin E 
Published: April 2023

Abstract

Objective. To compare a not adapted (NA) robust planning strategy with three fully automated online adaptive proton therapy (OAPT) workflows based on the same optimization method: dose mimicking (DM). The added clinical value and limitations of the OAPT methods are investigated for head and neck cancer (HNC) patients. Approach. The three OAPT strategies aimed at compensating for inter-fractional anatomical changes by mimiking different dose distributions on corrected cone beam CT images (corrCBCTs). Order by complexity, the OAPTs were: (1) online adaptive dose restoration (OADR) where the approved clinical dose on the planning-CT (pCT) was mimicked, (2) online adaptation using DM of the deformed clinical dose from the pCT to corrCBCTs (OADEF), and (3) online adaptation applying DM to a predicted dose on corrCBCTs (OAML). Adaptation was only applied in fractions where the target coverage criteria were not met (D98% < 95% of the prescribed dose). For 10 HNC patients, the accumulated dose distributions over the 35 fractions were calculated for NA, OADR, OADEF, and OAML. Main results. Higher target coverage was observed for all OAPT strategies compared to no adaptation. OADEF and OAML outperformed both NA and OADR and were comparable in terms of target coverage to initial clinical plans. However, only OAML provided comparable NTCP values to those from the clinical dose without statistically significant differences. When the NA initial plan was evaluated on corrCBCTs, 51% of fractions needed adaptation. The adaptation rate decreased significantly to 25% when the last adapted plan with OADR was selected for delivery, to 16% with OADEF, and to 21% with OAML. The reduction was even greater when the best plan among previously generated adapted plans (instead of the last one) was selected. Significance. The implemented OAPT strategies provided superior target coverage compared to no adaptation, higher OAR sparing, and fewer required adaptations.
The dispersion relation of a dark soliton
Authors: Meng Ling-Zheng , Mao Ning , Zhao Li-Chen 
Published: April 2023

Abstract
The energy-velocity relation of a dark soliton is usually derived by its exact solution, which has been used to explain the kinetic motion of the dark soliton widely in many-body physical systems. We perform a variational method to re-derive the dispersion relation, with the consideration that the number of particles of the dark soliton could be conserved. The re-derived dispersion relation is completely different from that given by the exact dark soliton solution. The validity of these two dispersion relations is tested by observing the motion of the dark soliton when we drive impurity atoms that coupled with the soliton. The results suggest that the dispersion relation given by the exact solution usually works better than the one with particle number conservation. This motivates us to reveal that density waves (carrying particle transport) are generated during the acceleration process of a dark soliton, in addition to the previously known sound waves (only carrying energy transport). We further show that the density wave emissions of dark solitons can be inhibited by increasing the impurity atom number, which is trapped by the dark soliton through nonlinear coupling. The discussion is meaningful for investigating and understanding the kinetic motion of dark solitons in many different circumstances.
Floquet engineering with quantum optimal control theory
Authors: Castro Alberto , Giovannini Umberto De , Sato Shunsuke A , Hübener Hannes , Rubio Angel 
Published: April 2023

Abstract
Floquet engineering consists in the modification of physical systems by the application of periodic time-dependent perturbations. The search for the shape of the periodic perturbation that best modifies the properties of a system in order to achieve some predefined metastable target behavior can be formulated as an optimal control problem. We discuss several ways to formulate and solve this problem. We present, as examples, some applications in the context of material science, although the methods discussed here are valid for any quantum system (from molecules and nanostructures to extended periodic and non periodic quantum materials). In particular, we show how one can achieve the manipulation of the Floquet pseudo-bandstructure of a transition metal dichalcogenide monolayer (MoS2).
Experimental benchmark data for Monte Carlo simulated radiation effects of gold nanoparticles. Part II: comparison of measured and simulated electron spectra from gold nanofoils
Authors: Borbinha Jorge , de la Fuente Rosales Liset , Hepperle Philine , Nettelbeck Heidi , Baek Woon Yong , Di Maria Salvatore , Rabus Hans 
Published: April 2023

Abstract
Electron emission spectra of a thin gold foil after photon interaction were measured over the energy range between 50 eV and 9500 eV to provide reference data for Monte Carlo radiation-transport simulations. Experiments were performed with the HAXPES spectrometer at the PETRA III high-brilliance beamline P22 at DESY (Hamburg, Germany) for photon energies just below and above each of the gold L-edges, that is, at 11.9 keV, 12.0 keV, 13.7 keV, 13.8 keV, 14.3 keV, and 14.4 keV. The data were analyzed to obtain the absolute values of the particle radiance of the emitted electrons per incident photon flux. Simulations of the experiment were performed using the Penelope and Geant4 Monte Carlo radiation-transport codes. Comparison of the measured and simulated results shows good qualitative agreement. On an absolute scale, the experiments tend to produce higher electron radiance values at the lower photon energies studied as well as at the higher photon energies for electron energies below the energy of the Au L3 photoelectron. This is attributed to the linear polarization of the photon beam in the experiments, something which is not considered in the simulation codes.
Highly efficient SnS-based inverted planar heterojunction solar cell with ZnO ETL
Authors: Islam Md Emtiajul , Islam Md Rasidul , Ahmmed Shamim , Hossain M Khalid , Rahman Md Ferdous 
Published: April 2023

Abstract
Tin Sulfide (SnS) is a promising absorber material for solar energy harvesting owing to the high absorption coefficient. Here, a novel inverted planar heterostructure of SnS based solar cell (ITO/NiOX/SnS/ZnO/Al) has been proposed for better efficiency among the different electron transport layers (ETLs), PCBM, C60, CeOX, and ZnO. The performance of the SnS based solar cell was theoretically studied by the Solar Cell Capacitance Simulator (SCAPS) software. Initially, we have been observed the device performance with different ETL materials to find the better ETL material. The layer parameters of the HTL, absorber layer, and ETLs have been optimized to find out the best performance of the device. The device showed efficiencies of around 26.44%, 26.33%, and 26.38% with the ETLs PCBM, C60, and CeOX respectively. The maximum power conversion efficiency (PCE) of ∼28.15% has been observed after incorporating ZnO ETL in the designed architecture of the SnS-based solar cell. Then, we have been investigated the performance of the SnS-based solar cell with ZnO ETL for the various value of carrier concentration, thickness, and bulk defect of the SnS absorber layer, defect of the interfaces of NiOX/SnS and SnS/ZnO, back metal contact’s work function, and its operating temperature. The variation of the different parameters has exhibited a substantial effect on the device performance. The VOC, JSC, FF, and PCE of the optimized SnS-based solar cell with ZnO ETL showed 0.8954 V, 37.316452 mA cm−2, 84.24%, and 28.15%, respectively. The visualization of the results indicates that ZnO might be a potential ETL for the highly efficient, low-cost inverted planar solar cells based on SnS.
Influence of Fe2O3@reduced graphene oxide nanocomposite on the structural, morphological, and optical features of the polyvinyl alcohol films for optoelectronic applications
Authors: Ahmed R M , Soliman T S , Vshivkov S A , Khalid A 
Published: April 2023

Abstract
Polyvinyl alcohol (PVA) films doped with Fe2O3-reduced graphene oxide (rGO) nanoparticles (NPs) were prepared using a casting-method. Fe2O3 NPs were synthesized via the hydrothermal process, and then Fe2O3 NPs were decorated on the graphene oxide (GO) sheets, where the GO was transferred to rGO during the sonication process. The obtained films were characterized using XRD and FTIR techniques. Optical absorption and transmission data were recorded via a UV–visible spectrophotometer and used to estimate various optical parameters. Increasing the amount of doped Fe2O3-rGO NPs in PVA decreased the ability of the prepared nanocomposites to allow visible light to pass through them. Solar material protection factor (SMPF) of PVA (11.93%) improved to 99.3%, corresponding to 2 wt% of Fe2O3-rGO NPs doped in the host matrix. The calculated values of the average refractive index are 2.18, 2.25, 2.36, 2.46, and 2.58, corresponding to 0 wt%, 0.5 wt%, 1 wt%, 1.5 wt%, and 2 wt% of Fe2O3-rGO NPs doped in PVA. Therefore, the average refractive index showed a dependence on Fe2O3-rGO NPs. Low energy region (E < 2.4 eV) showed dielectric relaxation time- energy dependent behavior, whereas the high energy region (E > 2.4 eV) displayed dielectric relaxation time- energy independent behavior. Increasing the content of the doped NPs in PVA resulted in lowering the surface and volume energy loss.
On the gas heating effect of helium atmospheric pressure plasma jet
Authors: do Nascimento Fellype , Gerling Torsten , Kostov Konstantin Georgiev 
Published: April 2023

Abstract
Plasma medicine is an emerging research field which has been driven by the development of plasma sources suitable to generate low temperature plasmas. In many cases, such devices can operate without a gas flow, producing a plasma discharge from the ambient air. However, the most common case is the use of a working gas at a given flow rate to produce a plasma jet. Helium (He) is one of the gases commonly used as the carrier gas to generate cold atmospheric pressure plasma jets (CAPPJs) due mainly to the easiness to ignite a gas discharge with it. However, in this work it was observed that most of the heating of a He CAPPJ can come just from the expansion of the He gas. This was found through measurements of gas temperature (T

gas
), using fiber optic temperature (FOT) sensors, and thermal output, using both FOT and infrared imaging with the He flow impinging on a copper (Cu) plate. Such findings were achieved through comparisons of T

gas
and the temperature on the Cu (T

Cu
) plate in the conditions with and without discharge ignition, as well as comparing T

gas
in the free gas/jet mode with and without discharge ignition. It was verified that the T

gas
values increased as the distance from the gas outlet was enlarged, especially at low He flow rates, even without discharge ignition. Despite the temperature increase with distance, it is possible to produce plasma jets with temperatures lower than 40 °C at low He flow rates.
Generation of optical

-antisymmetry in a coherent N-type atomic medium
Authors: Dutta Bibhas Kumar , Panchadhyayee Pradipta 
Published: April 2023

Abstract
We have proposed two schemes to exhibit




-antisymmetry in a four-level N-type atomic system interacting with two strong driving fields and a weak probe field. For both the schemes, the required spatially modulated coherence rendering




-antisymmetry is achieved by employing a double-channel Gaussian beam for one driving field with a single channel for the other driving field in different field configurations. In each scheme, for equal and opposite detunings of the double-channel Gaussian beam,




-antisymmetry can be obtained in the spatial domain. Such a way of control is unique to this model. Using the present method, it is possible to obtain




-antisymmetry for both the homogeneously and inhomogeneously broadened atoms.
Structure of shock wave in tungsten and titanium metals by using navier-stokes equation
Authors: Anand R K , Singh M K 
Published: April 2023

Abstract
Using the Navier–Stokes equation, we present the structure of a one-dimensional stationary shock wave formed in condensed alloy materials such as tungsten and titanium. In this study, the shock wave structure in the mentioned materials has been analysed by using several important parameters such as material viscosity, the Mie-Gruneisen parameter, and Mach number (M). One of our derived results is shock thickness, which is found to be of the order of 10−6 meters. In addition, we address a number of key insights into the shock wave interaction with tungsten and titanium. It should be noted that the validity of the model discussed in this study is limited to high M values, i.e., M ≥ 2.0.
Thermal ringdown of a Kerr black hole: overtone excitation, Fermi-Dirac statistics and greybody factor
Authors: Oshita Naritaka 
Published: April 2023

Abstract
We find a significant destructive interference among Kerr overtones in the early ringdown induced by an extreme mass-ratio merger of a massive black hole and a compact object, and that the ringdown spectrum apparently follows the Fermi-Dirac distribution. We numerically compute the spectral amplitude of gravitational waves induced by a particle plunging into a Kerr black hole and study the excitation of multiple quasi-normal (QN) modes. We find that the start time of ringdown is before the strain peak of the signal and corresponds to the time when the particle passes the photon sphere. When the black hole has the near-extremal rotation, the Kerr QN frequencies are close to the fermionic Matsubara frequencies with the Hawking temperature and the chemical potential of the superradiant frequency. We indeed find that the absolute square of the spectral amplitude apparently follows the Fermi-Dirac distribution with the chemical potential of around the real QN frequency of the fundamental mode. Fitting the Boltzmann distribution to the data in higher frequencies, the best-fit temperature is found out to be close to the Hawking temperature, especially for rapid rotations. In the near-extremal limit, the gravitational-wave spectrum exhibits a would-be Fermi degeneracy with the Fermi surface at the superradiant frequency ω = μ
H. We show that the greybody factor, i.e., the absorption cross section of a black hole, leads to the Fermi-Dirac distribution. As the greybody factor is another no-hair quantity of black holes, this opens a new possibility that we could test general relativity by observationally searching for the Boltzmann distribution in ringdown, provided that near-extremal black holes exist in the observable region. Indeed, it has been predicted that near-extremal supermassive black holes would exist at the center of some galaxies from the X-ray reflection spectroscopy. We could measure the mass and angular momentum of ringing black holes and could probe the Kerr/CFT correspondence by measuring the greybody factor imprinted on the ringdown spectrum.
Catalytic Role of H i in the Interstellar Synthesis of Complex Organic Molecule
Authors: Yang Shuming , Xie Peng , Liang Enwei , Wang Zhao 
Published: April 2023

Abstract
Using quantum chemical calculations, we model the pathways for synthesizing two purine nucleobases, adenine and guanine, in the gas-phase interstellar environment, surrounded by neutral atomic hydrogen (H i). H i is found active in facilitating a series of fundamental proton transfer processes of organic synthesis, including bond formation, cyclization, dehydrogenation, and H migration. The reactive potential barriers were significantly reduced in the alternative pathways created by H i, leading to a remarkable increase in the reaction rate. The presence of H i also lowered the reactive activation temperature from 757.8 K to 131.5–147.0 K, indicating the thermodynamic feasibility of these pathways in star-forming regions where some of the reactants have been astronomically detected. Our findings suggest that H i may serve as an effective catalyst for interstellar organic synthesis.
A (3+1)-dimensional equation of plasma drift waves perturbed by a singular potential in an infinite parallelepiped
Authors: Aldawish Ibtisam , Alazman Ibtehal , Jleli Mohamed , Samet Bessem 
Published: April 2023

AbstractWe investigate the existence and nonexistence of weak solutions to a (3+1)-dimensional equation of plasma drift waves perturbed by a singular potential. The considered equation is posed in an infinite parallelepiped, under an inhomogeneous Dirichlet boundary condition. We show that the dividing line with respect to existence or nonexistence is given by a critical exponent.
Development and evaluation of dose calculation algorithm with a combination of Monte Carlo and point-kernel methods for boron neutron capture therapy
Authors: Nojiri Mai , Takata Takushi , Hu Naonori , Sakurai Yoshinori , Suzuki Minoru , Tanaka Hiroki 
Published: April 2023

Abstract
We developed a ‘hybrid algorithm’ that combines the Monte Carlo (MC) and point-kernel methods for fast dose calculation in boron neutron capture therapy. The objectives of this study were to experimentally verify the hybrid algorithm and to verify the calculation accuracy and time of a ‘complementary approach’ adopting both the hybrid algorithm and the full-energy MC method. In the latter verification, the results were compared with those obtained using the full-energy MC method alone. In the hybrid algorithm, the moderation process of neutrons is simulated using only the MC method, and the thermalization process is modeled as a kernel. The thermal neutron fluxes calculated using only this algorithm were compared with those measured in a cubic phantom. In addition, a complementary approach was used for dose calculation in a geometry simulating the head region, and its computation time and accuracy were verified. The experimental verification indicated that the thermal neutron fluxes calculated using only the hybrid algorithm reproduced the measured values at depths exceeding a few centimeters, whereas they overestimated those at shallower depths. Compared with the calculation using only the full-energy MC method, the complementary approach reduced the computation time by approximately half, maintaining nearly same accuracy. When focusing on the calculation only using the hybrid algorithm only for the boron dose attributed to the reaction of thermal neutrons, the computation time was expected to reduce by 95% compared with the calculation using only the full-energy MC method. In conclusion, modeling the thermalization process as a kernel was effective for reducing the computation time.
Accessing radiation damage to biomolecules on the nanoscale by particle-scattering simulations
Authors: Hahn Marc Benjamin 
Published: April 2023

Abstract
Radiation damage to DNA plays a central role in radiation therapy to cure cancer. The physico-chemical and biological processes involved encompass huge time and spatial scales. To obtain a comprehensive understanding on the nano and the macro scale is a very challenging tasks for experimental techniques alone. Therefore particle-scattering simulations are often applied to complement measurements and aide their interpretation, to help in the planning of experiments, to predict their outcome and to test damage models. In the last years, powerful multipurpose particle-scattering framework based on the Monte-Carlo simulation (MCS) method, such as Geant4 and Geant4-DNA, were extended by user friendly interfaces such as TOPAS and TOPAS-nBio. This shifts their applicability from the realm of dedicated specialists to a broader range of scientists. In the present review we aim to give an overview over MCS based approaches to understand radiation interaction on a broad scale, ranging from cancerous tissue, cells and their organelles including the nucleus, mitochondria and membranes, over radiosensitizer such as metallic nanoparticles, and water with additional radical scavenger, down to isolated biomolecules in the form of DNA, RNA, proteins and DNA-protein complexes. Hereby the degradation of biomolecules by direct damage from inelastic scattering processes during the physical stage, and the indirect damage caused by radicals during the chemical stage as well as some parts of the early biological response is covered. Due to their high abundance the action of hydroxyl radicals (•OH) and secondary low energy electrons (LEE) as well as prehydrated electrons are covered in additional detail. Applications in the prediction of DNA damage, DNA repair processes, cell survival and apoptosis, influence of radiosensitizer on the dose distribution within cells and their organelles, the study of linear energy transfer (LET), the relative biological effectiveness (RBE), ion beam cancer therapy, microbeam radiation therapy (MRT), the FLASH effect, and the radiation induced bystander effect are reviewed.
Designing magnetocaloric materials for hydrogen liquefaction with light rare-earth Laves phases
Authors: Liu Wei , Gottschall Tino , Scheibel Franziska , Bykov Eduard , Fortunato Nuno , Aubert Alex , Zhang Hongbin , Skokov Konstantin , Gutfleisch Oliver 
Published: April 2023

Abstract
Magnetocaloric hydrogen liquefaction could be a ‘game-changer’ for liquid hydrogen industry. Although heavy rare-earth based magnetocaloric materials show strong magnetocaloric effects in the temperature range required by hydrogen liquefaction (77–20 K), the high resource criticality of the heavy rare-earth elements is a major obstacle for upscaling this emerging liquefaction technology. In contrast, the higher abundances of the light rare-earth elements make their alloys highly appealing for magnetocaloric hydrogen liquefaction. Via a mean-field approach, it is demonstrated that tuning the Curie temperature (T
C) of an idealized light rare-earth based magnetocaloric material towards lower cryogenic temperatures leads to larger maximum magnetic and adiabatic temperature changes (ΔS
T and ΔT
ad). Especially in the vicinity of the condensation point of hydrogen (20 K), ΔS
T and ΔT
ad of the optimized light rare-earth based material are predicted to show significantly large values. Following the mean-field approach and taking the chemical and physical similarities of the light rare-earth elements into consideration, a method of designing light rare-earth intermetallic compounds for hydrogen liquefaction is used: tuning T
C of a rare-earth alloy to approach 20 K by mixing light rare-earth elements with different de Gennes factors. By mixing Nd and Pr in Laves phase (Nd, Pr)Al2, and Pr and Ce in Laves phase (Pr, Ce)Al2, a fully light rare-earth intermetallic series with large magnetocaloric effects covering the temperature range required by hydrogen liquefaction is developed, demonstrating a competitive maximum effect compared to the heavy rare-earth compound DyAl2.