bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photodissociation dynamics of CF3CHO: C–C bond cleavage
Authors: Campbell Jyoti S. , Nauta Klaas , Kable Scott H. , Hansen Christopher S. 
Published: November 2021

The photodissociation dynamics of jet-cooled trifluoroacetaldehyde (CF3CHO) into radical products, CF3 + HCO, was explored using velocity mapped ion imaging over the wavelength range 297.5 nm ≤λ≤ 342.8 nm (33 613–29 172 cm−1) covering the entire section of the absorption spectrum accessible with solar actinic wavelengths at the ground level. After initial excitation to the first excited singlet state, S1, the radical dissociation proceeds largely via the first excited triplet state, T1, at excitation energies above the T1 barrier. By combining velocity-mapped ion imaging with high-level theory, we place this barrier at 368.3 ± 2.4 kJ mol−1 (30 780 ± 200 cm−1). After exciting to S1 at energies below this barrier, the dissociation proceeds exclusively via the ground electronic state, S0. The dissociation threshold is determined to be 335.7 ± 1.8 kJ mol−1 (28 060 ± 150 cm−1). Using laser-induced fluorescence spectroscopy, the origin of the S1 ← S0 transition is assigned at 28 903 cm−1. The S0 dissociation channel is active at the S1 origin, but the yield significantly increases above 29 100 cm−1 due to enhanced intersystem crossing or internal conversion.
Soil formation, nutrient supply and ecosystem productivity on basaltic lava vs rhyolitic pumice on Alcedo Volcano, Galápagos
Authors: Zehetner Franz , Jäger Heinke , Keiblinger Katharina M. , Dinter Tamara C. , Candra I. Nyoman , Bajraktarevic Armin , Puschenreiter Markus , Gerzabek Martin H. 
Published: November 2021

Context Rock type may exert strong control on pedogenesis and resulting soil characteristics. Little is known on how different volcanic lithologies influence soil formation and nutrient supply and thereby affect ecosystem productivity in volcanic landscapes. Aims The aim of this study was to investigate lithologic control on the mentioned properties and processes. Methods We conducted a side-by-side comparison of two contrasting sites in close proximity on Alcedo Volcano, Galápagos, one on basaltic lava and the other on rhyolitic pumice. Key results The lava site was covered by lush, stratified woodland, whereas the pumice site was covered by grassland with only few plant species. The soil on lava was a Leptosol, whereas on pumice, an Andosol had formed. Both soils had similar pH (6.0–6.5 in H2O), but the soil organic carbon stocks at the lava site were almost twice as high as at the pumice site (13.1 ± 1.6 vs 7.6 ± 1.3 kg m−2 to 25 cm depth). The soil at the pumice site had considerably lower levels of Mehlich-3-extractable P, Ca, Mg, Cu, Zn and B. Soil microbes at the pumice site had lower biomass P (and a higher C:P ratio) and excreted more phosphatase. The grass biomass here also showed lower (and deficient) levels of P and other nutrients compared to the lava site. Conclusions and implications The contrasting lithologies and their bearings on soil formation and nutrient availability diversify the aboveground and belowground ecosystems and favour the development of distinct ecological niches in close proximity.
Time-dependent quantum harmonic oscillator: a continuous route from adiabatic to sudden changes
Authors: Martínez-Tibaduiza Daniel , Pires Luis , Farina Carlos 
Published: November 2021

Abstract
In this work, we give a quantitative answer to the question: how sudden or how adiabatic is a frequency change in a quantum harmonic oscillator (HO)? We do that by studying the time evolution of a HO which is initially in its fundamental state and whose time-dependent frequency is controlled by a parameter (denoted by ϵ) that can continuously tune from a totally slow process to a completely abrupt one. We extend a solution based on algebraic methods introduced recently in the literature that is very suited for numerical implementations, from the basis that diagonalizes the initial Hamiltonian to the one that diagonalizes the instantaneous Hamiltonian. Our results are in agreement with the adiabatic theorem and the comparison of the descriptions using the different bases together with the proper interpretation of this theorem allows us to clarify a common inaccuracy present in the literature. More importantly, we obtain a simple expression that relates squeezing to the transition rate and the initial and final frequencies, from which we calculate the adiabatic limit of the transition. Analysis of these results reveals a significant difference in squeezing production between enhancing or diminishing the frequency of a HO in a non-sudden way.
Combined proton–photon treatment for breast cancer
Authors: Marc Louise , Fabiano Silvia , Wahl Niklas , Linsenmeier Claudia , Lomax Antony J , Unkelbach Jan 
Published: November 2021

Abstract

Objective. Proton therapy remains a limited resource due to gantry size and its cost. Recently, a new design without a gantry has been suggested. It may enable combined proton–photon therapy (CPPT) in conventional bunkers and allow the widespread use of protons. In this work, we explore this concept for breast cancer. Methods. The treatment room consists of a LINAC for intensity modulated radiation therapy (IMRT), a fixed proton beamline (FBL) with beam scanning and a motorized couch for treatments in lying positions with accurate patient setup. Thereby, proton and photon beams are delivered in the same fraction. Treatment planning is performed by simultaneously optimizing IMRT and IMPT plans based on the cumulative dose. The concept is investigated for three breast cancers where the goal is to minimize mean dose to the heart and lung while delivering 40.05 Gy in 15 fractions to the PTV with a SIB of 48 Gy to the tumor bed. The probabilistic approach is applied to mitigate the sensitivity to range uncertainties. Results. CPPT is particularly advantageous for irradiating concave target volumes that wrap around a curved chest wall. There, protons may deliver dose to the peripheral and medial parts of the target volume including lymph nodes. Thereby, the mean dose in normal tissues is reduced compared to single-modality IMRT. However, tangential photon beams may treat parts of the target volume near the interface to the lung. To ensure target coverage for range undershoot in an IMPT plan, proton beams have to deliberately overshoot into the lung tissue—a problem that can be mitigated via the photon component which ensures plan conformity and robustness. Conclusion. CPPT using an FBL may represent a realistic approach to make protons available to more patients. In addition, CPPT may generally improve treatment quality compared to both single-modality proton and photon treatments.
Global plasma modeling of a magnetized high-frequency plasma source in low-pressure nitrogen and oxygen for air-breathing electric propulsion applications
Authors: Mrózek Kryštof , Dytrych Tomáš , Moliš Pavel , Dániel Vladimír , Obrusník Adam 
Published: November 2021

Abstract
This work presents a global plasma model of a gridded air-breathing electric propulsion concept based on magnetized high-frequency plasma operating in the pressure range of 10−3 Pa to 1 Pa. We illustrate that the global plasma model reproduces the experimental measurements of the extracted current over two orders of magnitude in pressure. Consequently, we use the model to investigate the theoretical scalability of the plasma source, finding that the plasma source performance scales reasonably well with the average absorbed power per molecule, even though this scaling factor has its limits. The global model presented in this work is a model of a specific laboratory device and, in future, it can be adapted to very low Earth orbit conditions by adjusting the boundary conditions. The model was implemented using PlasmaSolve p3s-globalmodel software and the configuration file containing all the equations is provided to the community as supplementary material.
Simulations on the rheology of dry magneto-rheological fluid under various working modes
Authors: Pei Lei , Ma Zongqiang , Ma Dongjun , Shi Xiaofeng , Pan Hao , Wang Pei , Gong Xinglong 
Published: November 2021

Abstract
This work studied the rheological properties and magnetorheological (MR) mechanism of dry magnetorheological fluid (MRF) under various working modes. A novel simulation method combining the discrete element method and computational fluid dynamics was developed, in which the bilateral coupling between particles and the flow field of the matrix (air) was considered. The microstructures and mechanical properties in the redispersion process, shear mode, and valve mode were systematically simulated for the first time. The results indicated that dry MRF presented superior redispersion property and response time (several μs) than liquid-based MRFs. In shear mode, the magnetic dipolar force and friction force dominated the evolution of microstructures. In valve mode, the magnetic dipolar force and viscous drag force of air became the main interactions. Magnetic particles aggregated into sturdy chain structures and hindered the airflow. The MR effect in valve mode was the pressure gradient of the matrix, which increased up to 1.08 × 105 Pa m−1 with the increasing particle volume fractions and decreased under a large inflow velocity. The best MR effect in valve mode was achieved under a magnetic field of B = 63 mT. Simulations revealed the influence of dimensionless Mn and Re number on the MR effect. The pressure gradient of the matrix was controlled by the external field and can be utilized to design a dry MRF valve for precious and transient vibration control. Simulated dimensionless shear stress in shear mode agreed well with experiments. This work will promote the development and applications of novel high-performance MRFs.
Pitch-catch UGW-based multiple damage inference: a heterogeneous graph interpretation
Authors: Zhou Lu , Chen Si-Xin , Ni Yi-Qing , Jiang Liu 
Published: November 2021

Abstract
Ultrasonic guided waves (UGWs) have been extensively utilized in nondestructive testing and structural health monitoring (SHM) for detection and real-time monitoring of structural defects. By implementing multiple piezoelectric sensors onto a plane of the target structure to form a sensor network, damages within the sensing range can be detected or even visualized through a pitch-catch configuration. On the other hand, deep learning (DL) techniques have recently been widely used to aid UGW-based SHM when the waveform is over complicated to extract a specific mode of interest due to irregular structure or boundary reflections. However, not too much research work has been conducted to thoroughly combine sensor networks with DL. Existing research using DL approaches is mainly used to train and interpret waveforms from isolated sensor pairs. The topological structure of sensor layout and sensor-damage relative positions are hardly considered in the data-driven process. Motivated by these concerns, this study offers a first-of-its-kind perspective to interpret UGW data collected from a sensor network by mapping the physical sensor-damage layout into a graph, in which sensors and potential damages serve as graph vertices bearing heterogenous properties upon coming to UGWs and the process of UGW transmission between sensors are encapsulated as wavelike message passing between the vertices. A novel physics-informed end-to-end graph neural network model, named as WaveNet, was exquisitely and meticulously developed. By utilizing wave information and topological structure, WaveNet enables inference of multiple damages in terms of severity and location with satisfactory accuracy, even when the waveforms are chaotic, and the sensor arrangement is different at the training and testing stages. More importantly, beyond the SHM scenario, the present study is expected to enlighten new thinking on interconnecting physical wave propagation with virtual messaging passing in neural networks.
Experimental continuous-variable quantum key distribution using a thermal source
Authors: Huang Peng , Wang Tao , Chen Rui , Wang Ping , Zhou Yingming , Zeng Guihua 
Published: November 2021

Abstract
Gaussian-modulated coherent-state (GMCS) continuous-variable quantum key distribution (CVQKD) protocol can allow authenticated users to share secret key with unconditional security. So far, all previous experimental implementations of GMCS CVQKD schemes are based on active modulations, i.e. amplitude and phase modulators and quantum random number generator (QRNG) are required. However, high-speed modulation with high extinction ratio and stability is challenging, which is extremely remarkable in chip-scale silicon photonic realization. While the passive-state-preparation (PSP) CVQKD scheme, which explores the intrinsic field fluctuations of a thermal source, avoids the uses of active modulations and QRNG. In this paper, we experimentally realize the intact PSP CVQKD through a realistic optical fiber channel using off-the-shelf amplified spontaneous emission source. In particular, specially designed frame synchronization method is used to build the correlation between the data measured from the two legitimate parties, and excess noise are synthetically controlled to generate secure secret keys at the metro-area distances when considering the practical and non-negligible finite-size effects under collective Gaussian attacks. Due to the avoidance of modulators and QRNG, the passive state encoding scheme provides a promising direction of applicable high-speed, chip-based and even sunlight-based CVQKD with less cost and complexity.
Dispersion of elastic waves in an inhomogenous multilayered plate over a Winkler elastic foundation with imperfect interfacial conditions
Authors: Asif Muhammad , Nawaz Rab , Nuruddeen Rahmatullah Ibrahim 
Published: November 2021

Abstract
This study examines the dispersion of elastic waves in a strongly inhomogeneous three-layered plate resting on a Winkler elastic foundation in the presence of imperfect interfacial conditions alongside a stress-free upper face. The propagation of elastic waves in the plate is governed by the two-dimensional anti-plane shear motion. The asymptotic technique is employed for the analysis. The exact dispersion relation and the overall cut-off frequency are determined. Within the long-wave low-frequency region, the shortened polynomial dispersion relation corresponding to the exact dispersion relation has been computed and studied for a particular material contrast. The associated one-dimensional equations of motions are also derived in approximate forms for perfect interface as a case of interest. Finally, according to the findings of this investigation, the obtained approximate equations of motions for a three-layered plate remain valid over the entire low-frequency spectrum even in presence of an elastic foundation. We also examined the variational impacts of the dimensionless Winkler elastic foundation parameter G and the interface imperfect parameter γ on the dispersion branch of harmonic waves. Furthermore, to assure the long-wave low-frequency range, the numerical simulations and graphical visualization are presented by utilizing certain physical data.
Prenormative verification and validation of a protocol for measuring magnetite–maghemite ratios in magnetic nanoparticles
Authors: Bogart Lara K , Fock Jeppe , da Costa Geraldo M , Witte Kerstin , Greneche Jean-Marc , Zukrowski Jan , Sikora Marcin , Latta Drew E , Scherer Michelle M , Hansen Mikkel Fougt , Frandsen Cathrine , Pankhurst Quentin A 
Published: November 2021

Abstract
An important step in establishing any new metrological method is a prenormative interlaboratory study, designed to verify and validate the method against its stated aims. Here, the 57Fe Mössbauer spectrometric ‘centre of gravity’ (COG) method was tested as a means of quantifying the magnetite/maghemite (Fe3O4/γ-Fe2O3) composition ratio in biphasic magnetic nanoparticles. The study involved seven laboratories across Europe and North and South America, and six samples—a verification set of three microcrystalline mixtures of known composition, and a validation set of three nanoparticle samples of unknown composition. The spectra were analysed by each participant using in-house fitting packages, and ex post facto by a single operator using an independent package. Repeatability analysis was performed using Mandel’s h statistic and modified Youden plots. It is shown that almost all (83/84) of the Mandel h statistic values fall within the 0.5% significance level, with the one exception being borderline. Youden-based pairwise analysis indicates the dominance of random uncertainties; and in almost all cases the data analysis phase is only a minor contributor to the overall measurement uncertainty. It is concluded that the COG method is a robust and promising candidate for its intended purpose.
Recent developments in engineering design for the quasi-axisymmetric stellarator CFQS
Authors: Shimizu A. , Kinoshita S. , Isobe M. , Okamura S. , Ogawa K. , Nakata M. , Yoshimura Y. , Suzuki C. , Osakabe M. , Murase T. , Nakagawa S. , Tanoue H. , Xu Y. , Liu H.F. , Liu H. , Huang J. , Wang X. , Cheng J. , Xiong G. , Tang C. , Yin D. , Wan Y. 
Published: November 2021

Abstract
A quasi-axisymmetric stellarator, the CFQS, has been designed as a joint project of the National Institute for Fusion Science and Southwest Jiaotong University to prove intrinsic advantages of quasi-axisymmetry. Principal parameters of the CFQS are as follows: the major radius is 1 m, the magnetic field strength is 1 T, the aspect ratio is 4, and the toroidal periodic number is 2. The magnetic field configuration is designed based on that of the CHS-qa. Enhanced confinement properties within the context of neoclassical theory are achieved by its quasi-axisymmetric configuration. In the entire radial range, the magnetic well is retained to keep favourable stability features in the magnetohydrodynamic equilibrium. A magnetic field coil system was designed for the CFQS, which consists of 16 modular coils, 12 toroidal field coils, and 4 poloidal field coils. The supporting structure is designed to withstand strong electromagnetic force under 1 T operation, maintaining enough space for heating and diagnostic systems. The mock-up modular coil with the most complicated shape was constructed by Hefei Keye Electro Physical Equipment Manufacturing Co., Ltd. to check manufacturability and the achieved accuracy. A heat-run test was performed to check the temperature rise of conductors, and the capability of 1 T operation was confirmed. After various tests for the mock-up coil, construction of actual modular coils and the vacuum vessel has begun.
Therapeutic application of 3B-PEG injectable hydrogel/Nell-1 composite system to temporomandibular joint osteoarthritis
Authors: Wang Chenyu , Wang Yingnan , Wang Cunyi , Liu Chao , Li Wen , Hu Shiyu , Wu Na , Jiang Shijie , Shi Jiejun 
Published: November 2021

Abstract
This study aims to construct a composite system of the tri-block polyethylene glycol injectable hydrogel (3B-PEG IH) and neural epithelial growth factor-like protein 1 (Nell-1), and to analyze its therapeutic effect on temporomandibular joint osteoarthritis (TMJOA). Sol-gel transition temperature was measured via inverting test. The viscoelastic modulus curves was measured by rheometer. Degradation and controlled release profiles of 3B-PEG IH were drawn in vitro. In vivo gel retention and biocompatibility were completed subcutaneously on the back of rats. After primary chondrocytes were extracted and identified, the cell viability in 3B-PEG IH was measured. Evaluation of gene expression in hydrogel was performed by real-time polymerase chain reaction. TMJOA rabbits were established by intra-articular injection of type II collagenase. Six weeks after composite systems being injected, gross morphological score, micro-CT, histological staining and grading were evaluated. The rusults showed that different types of 3B-PEG IH all reached a stable gel state at 37 °C and could support the three-dimensional growth of chondrocytes, but poly(lactide-co-caprolactone)-block-poly(ethyleneglycol)-block-poly(lactide-co-caprolactone) (PLCL-PEG-PLCL) hydrogel had a wider gelation temperature range and better hydrolytic stability for about 4 weeks. Its controlled release curve is closest to the zero-order release kinetics. In vitro, PLCL-PEG-PLCL/Nell-1 could promote the chondrogenic expression and reduce the inflammatory expression. In vivo, TMJOA rabbits were mainly characterized by the disorder of cartilage structure and the destruction of subchondral bone. However, PLCL-PEG-PLCL/Nell-1 could reverse the destruction of the subchondral trabecula, restore the fibrous and proliferative layers of the surface, and reduce the irregular hyperplasia of fibrocartilage layer. In conclusion, by comparing the properties of different 3B-PEG IH, 20 wt% PLCL-PEG-PLCL hydrogel was selected as the most appropriate material. PLCL-PEG-PLCL/Nell-1 composite could reverse osteochondral damage caused by TMJOA, Nfatc1-Runx3 signaling pathway may play a role in it. This study may provide a novel, minimally-invasive therapeutic strategy for the clinical treatment of TMJOA.
Explainable machine learning predictions to support personalized cardiology strategies
Authors: Loh De Rong , Yeo Si Yong , Tan Ru San , Gao Fei , Koh Angela S 
Published: November 2021

Abstract

Aims
A widely practiced intervention to modify cardiac health, the effect of physical activity on older adults is likely heterogeneous. While machine learning (ML) models that combine various systemic signals may aid in predictive modelling, the inability to rationalize predictions at a patient personalized level is a major shortcoming in the current field of ML.

Methods and results
We applied a novel methodology, SHapley Additive exPlanations (SHAP), on a dataset of older adults n = 86 (mean age 72 ± 4 years) whose physical activity levels were studied alongside changes in their left ventricular (LV) structure. SHAP was tested to provide intelligible visualization on the magnitude of the impact of the features in their physical activity levels on their LV structure. As proof of concept, using repeated K-cross-validation on the train set (n = 68), we found the Random Forest Regressor with the most optimal hyperparameters, which achieved the lowest mean squared error. With the trained model, we evaluated its performance by reporting its mean absolute error and plotting the correlation on the test set (n = 18). Based on collective force plot, individually numbered patients are indicated on the horizontal axis, and each bandwidth implies the magnitude (i.e. effect) of physical parameters (higher in red; lower in blue) towards prediction of their LV structure.

Conclusions
As a tool that identified specific features in physical activity that predicted cardiac structure on a per patient level, our findings support a role for explainable ML to be incorporated into personalized cardiology strategies.