bluuebunny/crossref_metadata_2025 huggingface dataset:
Pre-folding fracturing in a foredeep environment: insights from the Carseolani Mountains (central Apennines, Italy)
Authors: Mercuri Marco , Smeraglia Luca , Curzi Manuel , Tavani Stefano , Maffucci Roberta , Pignalosa Antonio , Billi Andrea , Carminati Eugenio
Published: December 2021

Bedding-perpendicular joints striking parallel (longitudinal) and perpendicular (transverse) to both the axis of the hosting anticline and the trend of the foredeep-belt system are widely recognized in fold-and-thrust belts. Their occurrence has been commonly attributed to folding-related processes, such as syn-folding outer-arc extension, although they can also be consistent with a pre-folding foredeep-related fracturing stage. Here we report the pre-folding fracture pattern affecting the Pietrasecca Anticline, in the central Apennines (Italy), resolved by a detailed field structural analysis. Field observations, scan-lines and interpretation of virtual outcrops were used to study the intensity, distribution and the orientations of fracture pattern along the anticline. The fracture pattern of the Pietrasecca Anticline consists of longitudinal and transverse joints, oriented approximately perpendicular to bedding, and of a pre-folding longitudinal pressure-solution cleavage set, which is oblique to bedding regardless of the bedding dip. Cross-cutting relationships show that joints predated the development of the pressure-solution cleavage. Furthermore, joint intensity does not relate to the structural position along the anticline. Taken together, these observations suggest that jointing occurred in a foredeep environment before the Pietrasecca Anticline growth. Our work further demonstrates that joints striking parallel and orthogonal to the main fold axis do not necessarily represent syn-folding deformation structures.
A retrospective study of perioperative clinical seizures and epilepsy in children after operation for CHD
Authors: Ikegawa Takeshi , Ono Shin , Yamamoto Kouji , Shimizu Mikihiro , Yanagi Sadamitsu , Kim Ki-Sung , Ichikawa Yasuhiro , Ueda Hideaki
Published: December 2021

This study investigated the incidence and risk factors of perioperative clinical seizure and epilepsy in children after operation for CHD. We included 777 consecutive children who underwent operation from January 2013 to December 2016 at Kanagawa Children’s Medical Center, Kanagawa, Japan. Perinatal, perioperative, and follow-up medical data were collected. Elastic net regression and mediation analysis were performed to investigate risk factors of perioperative clinical seizure and epilepsy. Anatomic CHD classification was performed based on the preoperative echocardiograms; cardiac surgery was evaluated using Risk Adjustment in Congenital Heart Surgery 1. Twenty-three (3.0%) and 15 (1.9%) patients experienced perioperative clinical seizure and epilepsy, respectively. Partial regression coefficient with epilepsy as the objective variable for anatomical CHD classification, Risk Adjustment in Congenital Heart Surgery 1, and the number of surgeries was 0.367, 0.014, and 0.142, respectively. The proportion of indirect effects on epilepsy via perioperative clinical seizure was 22.0, 21.0, and 33.0%, respectively. The 15 patients with epilepsy included eight cases with cerebral infarction, two cases with cerebral haemorrhage, and three cases with hypoxic-ischaemic encephalopathy; white matter integrity was not found. Anatomical complexity of CHD, high-risk cardiac surgery, and multiple cardiac surgeries were identified as potential risk factors for developing epilepsy, with a low rate of indirect involvement via perioperative clinical seizure and a high rate of direct involvement independently of perioperative clinical seizure. Unlike white matter integrity, stroke and hypoxic-ischaemic encephalopathy were identified as potential factors for developing epilepsy.
Role of cardiac MRI in the prediction of pre-Fontan end-diastolic ventricular pressure
Authors: Pizzuto Alessandra , Ait-Ali Lamia , Marrone Chiara , Salvadori Stefano , Cuman Magdalena , Pak Vitali , Santoro Giuseppe , Festa Pierluigi
Published: December 2021

Background:

Growing evidence has emphasised the importance of ventricular performance in functionally single-ventricle patients, particularly concerning diastolic function. Cardiac MRI has been proposed as non-invasive alternative to pre-Fontan cardiac catheterisation in selected patients.

Aim of the study:

To identify clinical and cardiac magnetic resonance predictors of high pre-Fontan end-diastolic ventricular pressure.

Method:

In a retrospective single-centre study, 38 patients with functionally univentricular heart candidate for Fontan intervention, who underwent pre-Fontan cardiac catheterisation, beside a comprehensive cardiac MRI, echocardiographic, and clinical assessment were included. Medical and surgical history, cardiac magnetic resonance, cardiac catheterisation, echocardiographic, and clinical data were recorded. We investigated the association between non-invasive parameters and cardiac catheterisation pre-Fontan risk factors, in particular with end-diastolic ventricular pressure. Moreover, the impact of conventional invasive pre-Fontan risk factor on post-operative outcome as also assessed.

Results:

Post-operative complications were associated with higher end-diastolic ventricular pressure and Mayo Clinic indexes (p < 0.01 and p = 0.05, respectively). At receiver operating characteristic curve analysis end-diastolic ventricular pressure ≥ 10.5 mmHg predicted post-operative complications with a sensitivity of 75% and specificity of 88% (AUC: 0.795, 95% CI 0.576;1.000, p < 0.05). At multivariate analysis, both systemic right ventricle (OR: 23.312, 95% CI: 2.704–200.979, p < 0.01) and superior caval vein indexed flow (OR: 0.996, 95% CI: 0.993–0.999, p < 0.05) influenced end-diastolic ventricular pressure ≥ 10.5 mmHg.

Conclusions:

A reduced superior caval vein flow, evaluated at cardiac magnetic resonance, is associated with higher end-diastolic ventricular pressure a predictor of early adverse outcome in post-Fontan patients.
Assessing Moral Judgment Maturity Using the Sociomoral Reflection	Measure – Short Form Objective
Authors: Brugman Daniel , Beerthuizen Marinus G. C. J. , Helmond Petra , Basinger Karen S. , Gibbs John C.
Published: December 2021

Abstract: The Sociomoral Reflection Measure – Short Form Objective (SRM-SFO) aims to assess the reasoning and valuing components of moral judgment. A new index for measuring moral reasoning is introduced. The first study assessed construct validity by examining the structure and invariance of moral reasoning and moral value evaluation in community adolescents and adults from The Netherlands ( N = 1,583). Factor analyses supported the unidimensionality of both components. Measurement invariance was found across age groups, gender, and educational levels. Convergent validity was supported by positive relationships between moral reasoning and age in males and between moral reasoning and higher educational levels. Divergent validity was supported by the weak relationship of both components with social desirability and their negative relationship with self-centered orientation and self-reported antisocial/delinquent behavior. The second study included incarcerated juvenile delinquents ( N = 246). Measurement invariance was found for both components across delinquency groups. Furthermore, community participants reporting no antisocial/delinquent behavior showed higher levels on both components than community participants reporting antisocial/delinquent behavior and juvenile delinquents. The SRM-SFO provides acceptable to good psychometric properties for assessing the reasoning and valuing components of moral judgment. Its practical benefits support its use in large-scale research from young adolescence onward.
Radiocarbon in the Land and Ocean Components of the Community Earth System Model
Authors: Frischknecht Tobias , Ekici Altug , Joos Fortunat
Published: December 2021

Large amounts of the carbon‐isotope 14C, entering Earth's carbon cycle, were produced in the atmosphere by atomic bomb tests in the 1950s and 1960s. Here, we forced the ocean and land components of the Community Earth System Model with atmospheric 14CO2 over the historical period to constrain overturning time scales and fluxes. The uptake of bomb 14C by the land model is lower than observation‐based estimates. This mismatch is likely linked to too‐low 14C uptake by vegetation as the model overestimates 14C/C ratios of modern soils. This suggests model biases in forest productivity or wood carbon allocation and turnover, and, in turn, a bias in the forest sink of anthropogenic carbon. The ocean model matches the observation‐based global bomb 14C inventories when applying the quadratic relationship between gas transfer piston velocity and wind speed of Wanninkhof (2014), https://doi.org/10.4319/lom.2014.12.351 and the wind products from Large and Yeager or the Japanese Reanalysis Project. Simulated natural radiocarbon ages in the deep ocean are many centuries older than data‐based estimates, indicating too slow deep ocean ventilation. The sluggish circulation causes large biases in biogeochemical tracers and implies a delayed deep ocean uptake of heat and carbon in global warming projections. Our study suggests that 14C observations are key to constrain carbon fluxes and transport timescales for improved representations of land and ocean biogeochemical cycles and Earth system model projections.
A Marginal Stability Paradigm for Shear‐Induced Diapycnal Turbulent Mixing in the Ocean
Authors: Mashayek A. , Baker L. E. , Cael B. B. , Caulfield C. P.
Published: December 2021

Turbulent mixing induced by breaking internal waves is key to the ocean circulation and global tracer budgets. While the classic marginal shear instability of Richardson number ∼1/4 has been considered as potentially relevant to turbulent wave breaking, its relevance to flows that are not steady parallel shear flows has been suspect. We show that shear instability is indeed relevant in the ocean interior and propose a new marginal stability paradigm that relates the stability criterion based on Richardson number to one based on the ratio of Ozmidov and Thorpe turbulence scales. The new paradigm applies to both ocean interior and boundary layer flows. This allows for accurate quantification of the transition from downwelling to upwelling zones in a recently emerged paradigm of ocean circulation. Our results help climate models more accurately calculate the mixing‐driven deep ocean circulation and fluxes of tracers in the ocean interior.
San Andreas Fault Stress Change Due To Groundwater Withdrawal in California's Central Valley, 1860‐2010
Authors: Lundgren Paul , Liu Zhen , Ali S. Tabrez
Published: December 2021

Changes in groundwater storage in California's Central Valley (CV) are considered partly responsible for vertical uplift surrounding the southern CV and for stress changes on nearby faults. Questions remain regarding the distribution of stress on the central San Andreas fault (CSAF) from recent and historical drawdown of the CV aquifer over the past 150 years (1860–2010). We combine groundwater storage change estimates for the 2006–2010 drought with a three‐dimensional finite element model to estimate Coulomb failure stress change (ΔCFS) on the CSAF. We combine a simple parameterization of historical hydraulic head change for 1860–1960 with a CV hydrological model (1961–2003) to estimate visco‐elastic effects on ΔCFS total and 2010 rate. We find that ΔCFS on the CSAF correlates positively with shallow seismicity and low frequency earthquakes for both short‐term and long term stressing. Unloading uplift rates surrounding the southern CV only partially account for the observed vertical GPS rates.
Multiple Leaking Mode Dispersion Observations and Applications From Ambient Noise Cross‐Correlation in Oklahoma
Authors: Li Zhengbo , Shi Caiwang , Ren Hengxin , Chen Xiaofei
Published: December 2021

Surface wave imaging based on the normal modes extracted via ambient noise cross‐correlation has become a popular seismological technique during the last two decades. In addition to normal modes, which occupy most seismic wave energy, leaking modes with much weaker energy can also be obtained from ambient noise cross‐correlation. We report the observation of multimodal leaking mode dispersion curves retrieved from the cross‐correlation of ambient noise recorded by the LArge‐n Seismic Survey in Oklahoma array. The extracted leaking modes are closely related to the guided wave dispersion resulting from the layered P‐wave velocity (Vp) structure; hence, these modes can be used to invert the Vp structure. Moreover, the joint inversion of leaking modes and normal modes can not only accurately acquire the Vp structure but also effectively improve the fitness of normal modes from the inversion of only normal modes.
A New Parameterization of Turbulent Mixing Enhanced Over Rough Seafloor Topography
Authors: Hibiya Toshiyuki
Published: December 2021

Existing parameterizations of turbulent mixing enhanced over high‐wavenumber seafloor topography miss the fact that internal tidal waves emanating from the seafloor transform to internal lee waves as the tide‐topography interaction strengthens. This motivates us to replace the vertical decay scale of bottom‐enhanced turbulent mixing with the “vertical mean free path” of internal lee waves, namely, the average vertical distance over which internal lee waves propagate until they discharge their energy through interactions with the background internal waves. The resulting formula shows that the vertical extent of turbulent mixing becomes proportional to the abyssal barotropic tidal or steady flow amplitude squared and the inverse abyssal buoyancy frequency squared, but independent of the wavenumber of the seafloor, consistent with recent eikonal calculations and field observations. We propose a new parameterization of turbulent mixing enhanced over high‐wavenumber seafloor topography through incorporating the formulated vertical decay scale.
Post‐Perovskite Phase Transition in the Pyrolitic Lowermost Mantle: Implications for Ubiquitous Occurrence of Post‐Perovskite Above CMB
Authors: Kuwayama Yasuhiro , Hirose Kei , Cobden Laura , Kusakabe Mayu , Tateno Shigehiko , Ohishi Yasuo
Published: December 2021

We conducted in situ high‐pressure and ‐temperature X‐ray diffraction measurements of a pyrolitic mantle material up to 4480 K at 122–166 GPa in a laser‐heated diamond anvil cell. Results demonstrate that the phase transition between bridgmanite and post‐perovskite occurs in pyrolite within the lowermost mantle pressure range even at >4000 K. It suggests the ubiquitous occurrence of post‐perovskite above the core‐mantle boundary, which may be consistent with recent high‐quality seismology data that non‐observations of D” reflections are exceptions. Combining with earlier experiments performed at and below the normal lower‐mantle geotherm, our data show that the bridgmanite + post‐perovskite two‐phase region is ∼5 GPa thick and the dP/dT slope of the boundary is +6.5 ± 2.2 MPa/K, slightly smaller than previous theoretical calculations in MgSiO3. The global presence of rheologically weak post‐perovskite at the bottom of the mantle has profound implications in seismology, geodynamics, and heat transfer from the core.
Unsteady Magnetopause Reconnection Under Quasi‐Steady Solar Wind Driving
Authors: Zou Ying , Walsh Brian M. , Chen Li‐Jen , Ng Jonathan , Shi Xueling , Wang Chih‐Ping , Lyons Larry R. , Liu Jiang , Angelopoulos Vassilis , McWilliams Kathryn A. , Michael Ruohoniemi J.
Published: December 2021

The intrinsic temporal nature of magnetic reconnection at the magnetopause has been an active area of research. Both temporally steady and intermittent reconnection have been reported. We examine the steadiness of reconnection using space‐ground conjunctions under quasi‐steady solar wind driving. The spacecraft suggests that reconnection is first inactive, and then activates. The radar further suggests that after activation, reconnection proceeds continuously but unsteadily. The reconnection electric field shows variations at frequencies below 10 mHz with peaks at 3 and 5 mHz. The variation amplitudes are ∼10–30 mV/m in the ionosphere, and 0.3–0.8 mV/m at the equatorial magnetopause. Such amplitudes represent 30%–60% of the peak reconnection electric field. The unsteadiness of reconnection can be plausibly explained by the fluctuating magnetic field in the turbulent magnetosheath. A comparison with a previous global hybrid simulation suggests that it is the foreshock waves that drive the magnetosheath fluctuations, and hence modulate the reconnection.
Discovering spatiotemporal patterns of COVID-19 pandemic in South Korea
Authors: Kim Sungchan , Kim Minseok , Lee Sunmi , Lee Young Ju
Published: December 2021

A novel severe acute respiratory syndrome coronavirus 2 emerged in December 2019, and it took only a few months for WHO to declare COVID-19 as a pandemic in March 2020. It is very challenging to discover complex spatial–temporal transmission mechanisms. However, it is crucial to capture essential features of regional-temporal patterns of COVID-19 to implement prompt and effective prevention or mitigation interventions. In this work, we develop a novel framework of compatible window-wise dynamic mode decomposition (CwDMD) for nonlinear infectious disease dynamics. The compatible window is a selected representative subdomain of time series data, in which compatibility between spatial and temporal resolutions is established so that DMD can provide meaningful data analysis. A total of four compatible windows have been selected from COVID-19 time-series data from January 20, 2020, to May 10, 2021, in South Korea. The spatiotemporal patterns of these four windows are then analyzed. Several hot and cold spots were identified, their spatial–temporal relationships, and some hidden regional patterns were discovered. Our analysis reveals that the first wave was contained in the Daegu and Gyeongbuk areas, but it spread rapidly to the whole of South Korea after the second wave. Later on, the spatial distribution is seen to become more homogeneous after the third wave. Our analysis also identifies that some patterns are not related to regional relevance. These findings have then been analyzed and associated with the inter-regional and local characteristics of South Korea. Thus, the present study is expected to provide public health officials helpful insights for future regional-temporal specific mitigation plans.
Analysis of bone transport for ankle arthrodesis as a limb salvage procedure for the treatment of septic pilon fracture nonunion
Authors: Rosteius Thomas , Lotzien Sebastian , Königshausen Matthias , Rausch Valentin , Cibura Charlotte , Behr Björn , Lehnhardt Markus , Schildhauer Thomas Armin , Geßmann Jan
Published: December 2021

Septic nonunion of the pilon region with ankle joint infection is challenging for orthopedic surgeons to treat and is associated with a high risk of limb loss. Therefore, the aim of this study was to evaluate the effectiveness of bone transport for ankle arthrodesis in salvaging the limp after septic ankle destruction of the pilon region. We conducted a single-center, retrospective study including 21 patients treated for septic pilon nonunion with accompanying septic ankle destruction via Ilizarov bone transport between 2004 and 2018. In all cases, the complete excision of the nonunion and the resection of the ankle joint were carried out, followed by treating the bone and joint defect with a bone transport into the ankle arthrodesis. In 12/21 patients an additional flap transfer was required due to an accompanying soft tissue lesion. The overall healing and failure rate, final alignment and complications were recorded by the patients’ medical files. The bone-related and functional results were evaluated according to the Association for the Study and Application of Methods of Ilizarov (ASAMI) scoring system and a modified American Orthopedic Foot and Ankle Society (AOFAS) scale. After a mean follow-up of 30.9 ± 15.7 months (range 12–63 months), complete bone and soft tissue healing occurred in 18/21 patients (85.7%). The patients had excellent (5), good (7), fair (4), and poor (3) results based on the ASAMI functional score. Regarding bone stock, 6 patients had excellent, 7 good, and 6 fair results. The modified AOFAS score reached 60.6 ± 18 points (range, 29–86). In total, 33 minor complications and 28 major complications occurred during the study period. In 2 cases, a proximal lower leg amputation was performed due to a persistent infection and free flap necrosis with a large soft tissue defect, whereas in one case, persistent nonunion on the docking side was treated with a carbon orthosis because the patient refused to undergo an additional surgery. Bone transport for ankle arthrodesis offers the possibility of limb salvage after septic ankle destruction of the pilon region, with acceptable bony and functional results. However, a high number of complications and surgical revisions are associated with the treatment of this severe complication after pilon fracture.
Cloud point extraction associated with differential pulse voltammetry: preconcentration and determination of trace uranyl in natural water
Authors: Shi Siwei , Wu Haoxi , Zhang Ling , Xiong Penghui , Chen Denglei , Chen Lumin , Xu Jie , Qin Zhen , Liao Junsheng
Published: December 2021

A procedure for the electroanalytical determination of uranyl ions pre-concentrated from natural water by cloud point extraction (CPE) is developed in this study.
High temperature molecular-based phase transition compounds with tunable and switchable dielectric properties
Authors: Wan Min , Wang Yan-Ning , Liu Jing-Yuan , Tong Liang , Ye Si-Yu , Li Jun-Yi , Chen Li-Zhuang
Published: December 2021

Molecular-based dielectric switching compounds [ClEt-Dabco][ReO4]2 and [BrEt-Dabco][ReO4]2 with high-temperature phase transition.
Testing quantum speedups in exciton transport through a photosynthetic complex using quantum stochastic walks
Authors: Dudhe Naini , Sahoo Pratyush Kumar , Benjamin Colin
Published: December 2021

Photosynthesis is a highly efficient process, nearly 100 percent of the red photons falling on the surface of leaves reach the reaction center and get transformed into energy.
Palladium clusters, free and supported on surfaces, and their applications in hydrogen storage
Authors: Alonso Julio A. , López María J.
Published: December 2021

Palladium clusters enhance the hydrogen storage of nanoporous carbons.
Synthesis, structural and photophysical properties of dimethylphosphino(perfluoro-)phenylene-based gold(i) dimers
Authors: Müller Felix , Wickemeyer Lucas , Schwabedissen Jan , Ertl Martin , Neumann Beate , Stammler Hans-Georg , Monkowius Uwe , Mitzel Norbert W.
Published: December 2021

Driven by different weak non-covalent interactions [Au2(μ2-C6H4PMe2)2] and its aryl-perfluorinated analogue aggregate vastly differently in the solid state: the non-fluorinated prefers aurophilic interactions, the fluorinated aryl–aryl interactions.
Construction of a hierarchical ZnIn2S4/C3N4 heterojunction for the enhanced photocatalytic degradation of tetracycline
Authors: Min Feng , Wei Zhengqing , Yu Zhen , Xiao Yuting , Guo Shien , Song Renjie , Li Jinheng
Published: December 2021

A hierarchical heterojunction photocatalyst was fabricated by the in situ growth of ZnIn2S4 nanosheets on the hexagonal C3N4 tubes, which exhibited superior photocatalytic degradation efficiency of tetracycline under visible light irradiation.
A proton-conductive metal–organic framework based on imidazole and sulphate ligands
Authors: Mi Fu-Qi , Ma Fa-Xue , Zou Shui-Xiang , Zhan Dong-Sun , Zhang Teng
Published: December 2021

Built from a combination of metal cations, neutral azole ligands and sulphate anions, the MOF [Cu2(DHBDI)3(SO4)2]n exhibits good chemical stability in acids, bases and boiling water while showing high hydrophilicity and proton conductivity.
The garlic-derived organosulfur compound diallyl trisulphide suppresses tissue factor function
Authors: Okue Sachiko , Yaguchi Manami , Miura Atsushi , Ozaki-Masuzawa Yori , Hosono Takashi , Seki Taiichiro
Published: December 2021

DATS, a characteristic flavor component derived from garlic, inhibits tissue factor (TF) function and ameliorates plaque formation. DATS may serve as a dietary constituent that exerts beneficial effects on vascular diseases including atherosclerosis.
Glucopyranose from Pleurotus geesteranus prevent alcoholic liver diseases by regulating Nrf2/HO-1-TLR4/NF-κB signalling pathways and gut microbiota
Authors: Song Xinling , Cui Weijun , Meng Fanyun , Xia Qun , Li Xueping , Hou Minjie , Jia Le , Zhang Jianjun
Published: December 2021

PGPs from Pleurotus geesteranus enhanced hepatic functions by improving oxidative status via up-regulating Nrf2/HO-1 signalling pathways, and decreasing inflammation via down-regulating TLR4/NF-κB signalling pathways.
Role of genistein on the yield, structure and immunomodulatory activity of Monascus exopolysaccharides
Authors: Xie Liuming , Huang Zhibing , Meng Hui , Fan Zhibing , Shi Xiaoyi , Xie Jianhua
Published: December 2021

Monascus purpureus polysaccharides based on biomodification of genistein (G-EMP) exhibited stronger immunomodulatory activity in macrophages.
A dynamic passive thermoregulation fabric using metallic microparticles
Authors: Abebe Muluneh G. , Rosolen Gilles , Odent Jeremy , Raquez Jean-Marie , Maes Bjorn
Published: December 2021

Dynamic fabrics constitute a novel way to regulate a wearer's comfort. The use of mid-infrared scattering by metallic microspheres in a shape memory polymer is effective for such a passive temperature regulating textile.
Absolute negative mobility of active polymer chains in steady laminar flows
Authors: Wu Jian-Chun , Lin Fu-Jun , Ai Bao-Quan
Published: December 2021

We investigate the absolute negative mobility (ANM) of active polymer chains in steady laminar flows, and observe giant negative mobility in a broad range of parameter regimes.
Hybrid flux predictor‐based predictive flux control of permanent magnet synchronous motor drives
Authors: Fu Rong , Cao Yang
Published: December 2021

In the field of a model predictive control of a permanent magnet synchronous motor (PMSM), the predictive flux control (PFC) has received great attention, which only takes the stator flux vector as the control variable instead of the electromagnetic torque and the stator flux amplitude. Because PFC does not involve the cumbersome setting of weight factors, it is a promising control algorithm. However, the prediction of the stator flux vector depends on motor parameters, which inevitably reduces the robustness of the control system. In order to solve this problem, this paper proposes a hybrid flux predictor‐based predictive flux control of PMSM drives. The proposed stator flux predictor combines the voltage prediction model and the current prediction model, and the proportional–integral regulator is utilised to control the switching between the two prediction models. Experimental results show that the proposed algorithm has better dynamic, steady‐state and robust performances than the traditional predictive flux control.
Characteristics of pantograph‐catenary arc under low air pressure and strong airflow
Authors: Xu Zhilei , Gao Guoqiang , Wei Wenfu , Yang Zefeng , Xie Wenhan , Dong Keliang , Ma Yaguang , Yang Yan , Wu Guangning
Published: December 2021

Pantograph‐catenary arc fault is the primary factor threatening the stability of the power transmission for high‐speed railway. The motion characteristics of the pantograph‐catenary arc under low air pressure and strong airflow is significantly different from the case under atmospheric pressure. In this paper, an experimental platform of pantograph‐catenary arc was built to investigate arc root position‐time and arc column longitudinal drift height‐time characteristic curves under different air pressures and airflow velocites. Via analysing the corresponding results, it can be found that there are different arc root–arc column traction mechanisms at different stages of arc development. The arcing time and arc root stagnation time under low air pressure are significantly longer than the case under atmospheric pressure, resulting in more serious electrode ablation. The arc column longitudinal drift velocity and height are greater with the increase of airflow velocity. Two typical irregular arc motion phenomena—arc root jumping and arc reignition are observed. To clarify the internal mechanism of the above phenomenon, a magnetohydrodynamics (MHD) model of the pantograph‐catenary arc was lauched, the influence mechanism of the pantograph‐catenary arc temperature and voltage are studied, and the physical process of arc temperature oscillation is analysed. The research results provide theoretical support for arc protection in high‐altitude areas.
Evaluation of the ICRF stability from a position time series analysis
Authors: Liu N. , Lambert S. B. , Arias E. F. , Liu J.-C. , Zhu Z.
Published: December 2021

Context. The celestial reference frame is established on the basis of the absolute positions of extragalactic sources that are assumed to be fixed in space. The fixing of the axes is one of the crucial points for the concept behind the International Celestial Reference System (ICRS). However, due to various effects such as its intrinsic activity, the apparent position of the extragalactic sources may vary with time, resulting in a time-dependent deviation of the frame axes that are defined by the positions of these sources.

Aims. We aim to evaluate the axis stability of the third realization of the International Celestial Reference Frame (ICRF3).

Methods. We first derived the extragalactic source position time series from observations of very long baseline interferometry (VLBI) at the dual S∕X-band (2.3/8.4 GHz) between August 1979 and December 2020. We measured the stability of the ICRF3 axes in terms of the drift and scatter around the mean: (i) we estimated the global spin of the ICRF3 axes based on the apparent proper motion (slope of the position time series) of the defining sources of the ICRF3; (ii) we also constructed the yearly representations of the ICRF3 through annually averaged positions of the defining sources of the ICRF3 and estimated the dispersion in the axes orientation of these yearly frames.

Results. The global spin is no higher than 0.8 μas yr-1 for each ICRF3 axis with an uncertainty of 0.3 μas yr-1, corresponding to an accumulated deformation smaller than 30 μas for the celestial frame axes during 1979.6–2021.0. The axes orientation of the yearly celestial frame becomes more stable as time elapses, with a standard deviation of 10 μas–20 μas for each axis.

Conclusions. The axes of the ICRF3 are stable at approximately 10 μas–20 μas from 1979.6–2021.0 and the axes stability does not degrade after the adoption of the ICRF3.
Metamorphosis of trilobite-like drops on a surface: Electrically driven fingering
Authors: Granda Rafael , Yurkiv Vitaliy , Mashayek Farzad , Yarin Alexander L.
Published: December 2021

The experimental evidence reveals that sessile drops on a dielectric horizontal substrate subjected to sub-critical in-plane electric field acquire steady-state configurations where a balance between the pulling-outwards electric Maxwell stresses and the restoring surface tension has been attained. On the other hand, the experiments show that in supercritical electric field the Maxwell stresses become dominant and not only stretch the drop as a whole but also trigger growth of multiple fingers crawling toward electrodes on both sides of the drop. This makes the drops with fingers stretched along the electric field lines similar to some trilobites known from their imprints in petrified sediments studied in paleontology. It is shown experimentally and theoretically that fingers are triggered during the encounters of the spreading drop outlines with minor surface imperfections. Such surface defects (existing originally or pre-notched on purpose) result in fingers which can grow being directed by the electric-field lines. The present work details multiple experimental observations of the trilobite-like fingering with several types of commercially available paints (colloidal dispersions) and also provides a theoretical framework for this novel type of fingering.
Fluorophore-gold nanoparticle FRET/plasmonic lasers with the streptavidin-biotin complex as the acceptor–donor linkage
Authors: Rivera J. A. , Desai K. V. , Eden J. G.
Published: December 2021

Several Förster resonance energy transfer (FRET) lasers have been realized by employing the robust and versatile streptavidin-biotin (SPB) biocomplex as the acceptor–donor linkage. SPB offers a fixed acceptor–donor separation (“ruler”) of <6 nm, which lies within the Förster radius for a broad range of donors and acceptors. A Cy3-SPB-Cy5 conjugate laser (where Cy3 and Cy5 are cyanine dyes) peaking at λ ∼ 708 nm has been observed, and its bandwidth and threshold pump energy (at 532 nm) have been measured to be ∼4.5 nm and 118 µJ (corresponding to a pump energy density of 179 ± 5 µJ/mm2), respectively. Depolarization of the linearly polarized pump optical field by this FRET process is found to be <12%. To tether the acceptor and donor, the SPB complex requires only that either be conjugated, thereby allowing FRET processes to be examined among an extensive set of biomolecules, inorganics, and nanoantenna acceptors, for example. As a result, fluorophore-nanoparticle lasers having characteristics of both FRET lasers and plasmonic emitters have been demonstrated. Laser spectra and the phase shift induced by a 10 or 100 nm gold nanoparticle tethered to the Cy3-SPB complex suggest that both the fluorescent protein and nanoparticle are able to act as an acceptor. The brightness associated with this new class of fluorophore/nanostructure FRET lasers will broaden the scope of accessible biomedical diagnostics, including cellular imaging and the detection of DNA and proteins.
On the relations between large-scale models of superfluid helium-4
Authors: Sýkora Martin , Pavelka Michal , La Mantia Marco , Jou David , Grmela Miroslav
Published: December 2021

Superfluid helium-4 is characterized by extremely small values of kinematic viscosity, and its thermal conductivity can be huge, orders of magnitude larger than that of water or air. Additionally, quantum vortices may exist within the fluid. Therefore, its behavior cannot be explained by using the classical tools of Newtonian fluid mechanics, and, over the years, a few alternative models have been proposed. In order to highlight similarities and differences between these models, we recast them within a unifying framework, the general equation for non-equilibrium reversible-irreversible coupling (GENERIC). We begin by comparing the original two-fluid model, developed by Tisza and Landau, with the Hall–Vinen–Bekarevich–Khalatnikov model, both prescribing two types of fluid motion and two fluid densities, at flow scales appreciably larger than the typical distance between quantum vortices. We find from the geometrical structure of the models that only one fluid density plays the role of state variable, which should be taken into account when choosing an adequate expression for the free energy. We also recast within the GENERIC framework the one-fluid model of superfluid helium-4, where the inviscid component of two-fluid models is replaced by a caloric quantity, such as entropy. We find that the corresponding geometrical structures are analogous, with the roles of density and entropy swapped. In short, our work demonstrates that the studied models are compatible with each other, at least when focusing on the reversible parts of the models.
An exotic microstructured globular state formed by a single multiblock copolymer chain
Authors: Petrov Artem , Gavrilov Alexey A. , Chertovich Alexander
Published: December 2021

In this work, we studied the equilibrium structures formed by a single (AB)k multiblock copolymer chain. Within our model, the interactions between the A-type beads were repulsive and the B-type beads could form pairwise reversible bonds with each other (BB-bonds). Our goal was to investigate how the formation of pairwise reversible bonds between the A-type beads and the B-type beads (AB-bonds) affected the structure of the chain. We observed the formation of well-studied intramolecular micelles when the AB-bonds were absent; however, the chain folding changed dramatically when the formation of the AB-bonds was introduced. In this case, the multiblock copolymer formed a globule, which had a unique heterogeneous checkerboard-like distribution of the contact density. We discovered that contacts of beads of different types (i.e., AB-contacts) occurred much more frequently than contacts of beads of the same type (i.e., AA- and BB-contacts) in these structures. This effect can be explained by a simple model of chemical equilibrium in a two-component fluid of reversibly interacting particles, which can be solved exactly. This novel type of folding can serve as a basic model for any (AB)k multiblock copolymer chain with a non-vanishing attraction between A and B blocks.
Protected solid-state qubits
Authors: Danon Jeroen , Chatterjee Anasua , Gyenis András , Kuemmeth Ferdinand
Published: December 2021

The implementation of large-scale fault-tolerant quantum computers calls for the integration of millions of physical qubits with very low error rates. This outstanding engineering challenge may benefit from emerging qubits that are protected from dominating noise sources in the qubits' environment. In addition to different noise reduction techniques, protective approaches typically encode qubits in global or local decoherence-free subspaces, or in dynamical sweet spots of driven systems. We exemplify such protected qubits by reviewing the state-of-art in protected solid-state qubits based on semiconductors, superconductors, and hybrid devices.
Improved gas-kinetic unified algorithm for high rarefied to continuum flows by computable modeling of the Boltzmann equation
Authors: Li Zhi-Hui , Hu Wen-Qiang , Wu Jun-Lin , Peng Ao-Ping
Published: December 2021

In this paper, we present an improved gas-kinetic unified algorithm (IGKUA) for high rarefied transition to continuum flows by computable modeling of Boltzmann equation. Compared with the original algorithm, the new method utilizes less needed discrete velocity ordinate points to obtain accurate results and removes the dependency of flow regime on computational time step, which can speed up the convergence in continuum flows. One of the novel strategies adopted in IGKUA is to develop a type of gas-kinetic quadrature rule that can exactly preserve conservation constraint of the model by adjusting the integral weights, increasing efficiency, and reducing nonphysical sources. Another key innovation is to introduce the analytical solutions of colliding-relaxation equation by considering the evolutions of associated macroscopic flow variables first, leading to no limit on the permissible time step. Numerical explicit and implicit schemes for unsteady flows are constructed to solve the physical convective equation, and Fourier spectral method is applied for the molecular-velocity convective movement equation analytically when the flows are under external-force fields. The IGKUA is tested using some numerical examples, including the shock-tube problems, Rayleigh flow, Couette flow, lid-driven cavity, external force-driven Poiseuille flow, and hypersonic flow past an infinite flat plate. Simulation results are in high resolution of the flow fields and match well with the results of the analytical, direct simulation Monte Carlo, Navier–Stokes solvers, and other reference methods. In addition, the new algorithm is better than the original one in the aspects of computational amount and time, which are more obvious when simulating the continuum flows.
Evolutions of strain rate and dissipation rate of kinetic energy in turbulent premixed flames
Authors: Chakraborty Nilanjan , Kasten Christian , Ahmed Umair , Klein Markus
Published: December 2021

The statistical behaviors of the evolutions of the components of the strain rate tensor and Favre-averaged dissipation rate of kinetic energy are analyzed using direct numerical simulations of statistically planar turbulent premixed flames propagating into forced unburned gas turbulence for different turbulence intensities spanning a range of different Karlovitz numbers. The pressure Hessian contribution and the combined molecular diffusion and dissipation terms are found to play dominant roles in the transport equations of diagonal strain rate components and the Favre-averaged dissipation rate of kinetic energy for flames with small Karlovitz numbers. By contrast, the leading order balance is maintained between the strain rate, vorticity, and molecular dissipation contributions for flames with large Karlovitz numbers, similar to non-reacting turbulent flows. The contributions of the terms arising from the correlation between pressure and density gradients and pressure Hessian in the strain rate and dissipation rate of kinetic energy transport equations weaken in comparison to the magnitude of the molecular dissipation contribution with an increase in Karlovitz number. These behaviors have been explained in terms of the alignments of vorticity, pressure gradient, and pressure Hessian eigenvectors with strain rate eigendirections. The magnitudes of the terms in the transport equation of the Favre-averaged dissipation rate of kinetic energy are also found to increase with increasing Karlovitz number, which is explained with the help of a detailed scaling analysis. This scaling analysis also explains the leading order contributions to the dissipation rate of kinetic energy for different combustion regimes.
Electroosmotic flow of Maxwell fluid in a microchannel of isosceles right triangular cross section
Authors: Yang Xu , Wang Shaowei , Zhao Moli , Xiao Yue
Published: December 2021

This work is presented to study the unsteady oscillatory electroosmotic flow of Maxwell fluid in a microchannel of an isosceles right triangular cross section. An external time-dependent electric field is applied and high zeta potential conditions are considered. Due to the difficulty of theoretical solution, a numerical method is adopted. The numerical solutions are derived by employing the finite difference method. Finally, the effects of some dimensionless variables, the relaxation time, the angular Reynolds number, the wall zeta potential, and the ratio between the typical length and the Debye length on the velocity profiles, are interpreted graphically.
Thermoelectricity: Thomson vs Onsager, with advice from Maxwell
Authors: Goddard J. D.
Published: December 2021

This paper deals with the long-standing conflict between interpretations of thermoelectricity based on the original reversible thermodynamics of Thomson and the later irreversible thermodynamics of Onsager. It is shown that, by a slight modification of the Maxwellian relaxation treated in a previous paper [J. Goddard and K. Kamrin, “Dissipation potentials from elastic collapse,” Proc. R. Soc. A 475, 20190144 (2019)], Onsager's symmetry is simply a reflection of the underlying symmetry of equilibrium thermodynamics. It is also shown that a modern interpretation of Thomson's thermodynamics, as given recently by the present author, reveals thermoelectricity to be the analog of a fluid-mechanical transport process with the limit of thermodynamic equilibrium corresponding to the convection-dominated regime of large Péclet number.
Extension of the primitive model by hydration shells and its impact on the reversible heat production during the buildup of the electric double layer
Authors: Pelagejcev Philipp , Glatzel Fabian , Härtel Andreas
Published: December 2021

Recently, the reversible heat production during the electric double layer (EDL) buildup in a sodium chloride solution was measured experimentally [Janssen et al., Phys. Rev. Lett. 119, 166002 (2017)] and matched with theoretical predictions from density functional theory and molecular dynamics simulations [Glatzel et al., J. Chem. Phys. 154, 064901 (2021)]. In the latter, it was found that steric interactions of ions with the electrode’s walls, which result in the so-called Stern layer, are sufficient to explain the experimental results. As only symmetric ion sizes in a restricted primitive model were examined, it is instructive to investigate systems of unequal ion sizes that lead to modified Stern layers. In this work, we explore the impact of ion asymmetry on the reversible heat production for each electrode separately. In this context, we further study an extension of the primitive model where hydration shells of ions can evade in the vicinity of electrode’s walls. We find a strong dependence on system parameters such as particle sizes and the total volume taken by particles. Here, we even found situations where one electrode was heated and the other electrode was cooled at the same time during charging, while, in sum, both electrodes together behaved very similarly to the already mentioned experimental results. Thus, heat production should also be measured in experiments for each electrode separately. By this, the importance of certain ingredients that we proposed to model electrolytes could be confirmed or ruled out experimentally, finally leading to a deeper understanding of the physics of EDLs.
Molecular mechanisms of cardiac actomyosin transforming from rigor state to post-rigor state
Authors: Sun Shengjie , Karki Chitra , Gao Bruce Z. , Li Lin
Published: December 2021

Sudden cardiac death contributed to half of all deaths from cardiovascular diseases. The mechanism of the kinetic cycle of cardiac myosin is crucial for heart protection and drug development. The state change in the myosin kinetic cycle from the rigor state to the post-rigor state is fundamental to explain binding and dissociation. Here, we used β-cardiac myosin in the rigor and post-rigor states to model the actomyosin complexes. Molecular dynamics simulations, electrostatic analysis, and energetic analysis of actomyosin complexes were performed in this work. The results showed that there are fewer interactions and lower electrostatic binding strength in the post-rigor state than in the rigor state. In the post-rigor state, there were higher free binding energy, fewer salt bridges, and fewer hydrogen bonds. The results showed a lower binding affinity in the post-rigor state than in the rigor state. The decrease in the binding affinity provided important conditions for dissociation of the myosin from the actin filament. Although previous studies focused mostly on the binding process, this study provides evidence of dissociation, which is even more important in the myosin kinetic cycle. This research on the mechanism of myosin kinetic cycles provides a novel direction for future genetic disease studies.
Element doping-induced effects in Zn-doped CdTe quantum-dot system: Insights from an ultrafast dynamics perspective
Authors: Zhang Jiachen , Zhang Lei , Zhang Qun
Published: December 2021

Element doping can have a profound impact on the photoelectrochemical properties of quantum dots (QDs); nevertheless, the hitherto known information in this regard is mainly from the steady-state characterizations and remains lacking input from the dynamics perspective. Herein, we present a systematic scrutiny of the element doping-induced effects in Zn-doped CdTe QDs. By means of steady-state/time-resolved/temperature-dependent photoluminescence spectroscopy and ultrafast transient absorption spectroscopy, we reveal that the slight Zn-doping in CdTe QDs can greatly affect the involved carrier relaxation dynamics through a density-of-state modification for both near-band-edge and localized surface trap states. Furthermore, such slight doping is found to be quite significant in modulating the photoreduction efficiency (of particular relation to the localized surface trap states) as well as altering the involved relaxation/reaction activation energy and phonon effect in this QDs system. This work enriches our fundamental understanding of the element doping-induced surface/interface effects, from the dynamics perspective in particular, and, hence, offers helpful guidance for QDs-based photoelectrochemical design and optimization.