bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spiral waves within a bistability parameter region of an excitable medium
Authors: Zykov V S , Bodenschatz E 
Published: January 2022

Abstract
Spiral waves are a well-known and intensively studied dynamic phenomenon in excitable media of various types. Most studies have considered an excitable medium with a single stable resting state. However, spiral waves can be maintained in an excitable medium with bistability. Our calculations, performed using the widely used Barkley model, clearly show that spiral waves in the bistability region exhibit unique properties. For example, a spiral wave can either rotate around a core that is in an unexcited state, or the tip of the spiral wave describes a circular trajectory located inside an excited region. The boundaries of the parameter regions with positive and ‘negative’ cores have been defined numerically and analytically evaluated. It is also shown that the creation of a positive or ‘negative’ core may depend on the initial conditions, which leads to hysteresis of spiral waves. In addition, the influence of gradient flow on the dynamics of the spiral wave, which is related to the tension of the scroll wave filaments in a three-dimensional medium, is studied.
Hubble-induced phase transitions on the lattice with applications to Ricci reheating
Authors: Bettoni Dario , Lopez-Eiguren Asier , Rubio Javier 
Published: January 2022

Abstract
Using 3+1 classical lattice simulations, we follow the symmetry breaking pattern and subsequent non-linear evolution of a spectator field non-minimally coupled to gravity when the post-inflationary dynamics is given in terms of a stiff equation-of-state parameter. We find that the gradient energy density immediately after the transition represents a non-negligible fraction of the total energy budget, steadily growing to equal the kinetic counterpart. This behaviour is reflected on the evolution of the associated equation-of-state parameter, which approaches a universal value 1/3, independently of the shape of non-linear interactions. Combined with kination, this observation allows for the generic onset of radiation domination for arbitrary self-interacting potentials, significantly extending previous results in the literature. The produced spectrum at that time is, however, non-thermal, precluding the naive extraction of thermodynamical quantities like temperature. Potential identifications of the spectator field with the Standard Model Higgs are also discussed.
Probing neutrino decay scenarios by using the Earth matter effects on supernova neutrinos
Authors: Delgado Edwin A. , Nunokawa Hiroshi , Quiroga Alexander A. 
Published: January 2022

Abstract
The observation of Earth matter effects in the spectrum of neutrinos coming from a next galactic core-collapse supernova (CCSN) could, in principle, reveal if neutrino mass ordering is normal or inverted. One of the possible ways to identify the mass ordering is through the observation of the modulations that appear in the spectrum when neutrinos travel through the Earth before they arrive at the detector. These features in the neutrino spectrum depend on two factors, the average neutrino energies, and the difference between the primary neutrino fluxes of electron and other flavors produced inside the supernova. However, recent studies indicate that the Earth matter effect for CCSN neutrinos is expected to be rather small and difficult to be observed by currently operating or planned neutrino detectors mainly because of the similarity of average energies and fluxes between electron and other flavors of neutrinos, unless the distance to CCSN is significantly smaller than the typically expected one, ∼ 10 kpc. Here, we are looking towards the possibility if the non-standard neutrino properties such as decay of neutrinos can enhance the Earth matter effect. In this work we show that invisible neutrino decay can potentially enhance significantly the Earth matter effect for both νe and ν̅e channels at the same time for both mass orderings, even if the neutrino spectra between electron and other flavors of neutrinos are very similar, which is a different feature not expected for CCSN neutrinos with standard oscillation without the decay effect.
Method of Separating Cosmic-Ray Positrons from Electrons in the DAMPE Experiment
Authors: Dai Hao-Ting , Zang Jing-Jing , Wang Ying , Luo Chuan-Ning , Zhang Yun-Long , Zhang Zhi-Yong , Wei Yi-Feng , Wu Li-Bo , Liu Cheng-Ming , Zhao Cong , Wang Xiao-Lian , Xu Zi-Zong , Huang Guang-Shun 
Published: January 2022

Abstract
A method of identifying positron/electron species from the cosmic rays was studied in the DArk Matter Particle Explorer (DAMPE) experiment. As there is no onboard magnet on the satellite, the different features imposed by the geomagnetic field on these two species were exploited for the particle identification. Application of this method to the simulation of on-orbit electrons/positrons/protons and the real flight data proves that separately measuring the CR positrons/electrons with DAMPE is feasible, though limited by the field of view for the present observation data. Further analysis on the positron flux with this method can be expected in the future.
Temperature Analysis of Flaring (AR 11283) and Non-flaring (AR 12194) Coronal Loops
Authors: Fathalian Narges , Somayeh Hosseini Rad Seyedeh , Alipour Nasibeh , Safari Hossein 
Published: January 2022

Abstract
Here, we study the temperature structure of flaring and non-flaring coronal loops, using extracted loops from images taken in six extreme ultraviolet channels recorded by Atmospheric Imaging Assembly/Solar Dynamics Observatory. We use data for loops of an X2.1-class-flaring active region (AR 11283) during 22:10 UT until 23:00 UT, on 2011 September 6; and a non-flaring active region (AR 12194) during 08:00:00 UT until 09:00:00 UT on 2014 October 26. By using the spatially synthesized Gaussian differential emission measure (DEM) forward-fitting method, we calculate the peak temperatures for each strip of the loops. We apply the Lomb–Scargle method to compute the oscillation periods for the temperature series of each strip. The periods of the temperature oscillations for the flaring loops ranged from 7 to 28.4 minutes. These temperature oscillations show very close behavior to the slow-mode oscillation. We observe that the temperature oscillations in the flaring loops started at least around 10 minutes before the transverse oscillations and continue for a long time duration even after the transverse oscillations ended. The temperature amplitudes increased during the flaring time (20 minutes) in the flaring loops. The periods of the temperatures obtained for the non-flaring loops ranged from 8.5 to 30 minutes, but their significances are less (below 0.5) in comparison with the flaring ones (near to one). Hence the detected temperature periods for the non-flaring loops’ strips are less probable in comparison with the flaring ones, and maybe they are just fluctuations. Based on our confined observations, it seems that the flaring loops’ periods show more diversity and their temperatures have wider ranges of variation than the non-flaring ones. More accurate commentary in this respect requires more extensive statistical research and broader observations.
Intrinsic somatosensory feedback supports motor control and learning to operate artificial body parts
Authors: Amoruso E , Dowdall L , Kollamkulam M T , Ukaegbu O , Kieliba P , Ng T , Dempsey-Jones H , Clode D , Makin T R 
Published: January 2022

Abstract

Objective. Considerable resources are being invested to enhance the control and usability of artificial limbs through the delivery of unnatural forms of somatosensory feedback. Here, we investigated whether intrinsic somatosensory information from the body part(s) remotely controlling an artificial limb can be leveraged by the motor system to support control and skill learning. Approach. We used local anaesthetic to attenuate somatosensory inputs to the big toes while participants learned to operate through pressure sensors a toe-controlled and hand-worn robotic extra finger. Motor learning outcomes were compared against a control group who received sham anaesthetic and quantified in three different task scenarios: while operating in isolation from, in synchronous coordination, and collaboration with, the biological fingers. Main results. Both groups were able to learn to operate the robotic extra finger, presumably due to abundance of visual feedback and other relevant sensory cues. Importantly, the availability of displaced somatosensory cues from the distal bodily controllers facilitated the acquisition of isolated robotic finger movements, the retention and transfer of synchronous hand-robot coordination skills, and performance under cognitive load. Motor performance was not impaired by toes anaesthesia when tasks involved close collaboration with the biological fingers, indicating that the motor system can close the sensory feedback gap by dynamically integrating task-intrinsic somatosensory signals from multiple, and even distal, body-parts. Significance. Together, our findings demonstrate that there are multiple natural avenues to provide intrinsic surrogate somatosensory information to support motor control of an artificial body part, beyond artificial stimulation.
Electrochemical microelectrode degradation monitoring: in situ investigation of platinum corrosion at neutral pH
Authors: Doering Moritz , Kieninger Jochen , Urban Gerald A , Weltin Andreas 
Published: January 2022

Abstract

Objective. The stability of platinum and other noble metal electrodes is critical for neural implants, electrochemical sensors, and energy sources. Beyond the acidic or alkaline environment found in most electrochemical studies, the investigation of electrode corrosion in neutral pH and chloride containing electrolytes is essential, particularly regarding the long-term stability of neural interfaces, such as brain stimulation electrodes or cochlear implants. In addition, the increased use of microfabricated devices demands the investigation of thin-film electrode stability in combination with electrode performance. Approach. We developed a procedure of electrochemical methods for continuous tracking of electrode degradation in situ over the complete life cycle of platinum thin-film microelectrodes in a unique combination with simultaneous chemical sensing. We used chronoamperometry and cyclic voltammetry to measure electrode surface and analyte redox processes, together with accelerated electrochemical degradation. Main results. We compared degradation between thin-film microelectrodes and bulk electrodes, neutral to acidic pH, different pulsing schemes, and the presence of the redox active species oxygen and hydrogen peroxide. Results were confirmed by electrochemical impedance spectroscopy, as well as mechanical profilometry and microscopy to determine material changes on a nanometer scale. We found that electrode degradation is mainly driven by repeated formation and removal of the platinum surface oxide, also within the electrochemical stability window of water. There was no considerable difference between thin-film micro- and macroscopic bulk electrodes or in the presence of reactive species, whereas acidic pH or extending the potential window led to increased degradation. Significance. Our results provide valuable fundamental information on platinum microelectrode degradation under conditions found in biomedical applications. For the first time, we employed a unified method to report quantitative data on electrode degradation up to a defined endpoint. Our method is a widely applicable framework for comparative long-term studies of electrode micro-/nanomaterial, sensor and neural interface stability.
Core-edge 2D fluid modeling of full tokamak discharge with varying magnetic equilibrium: from WEST start-up to ramp-down
Authors: Scotto d’Abusco M. , Giorgiani G. , Artaud J.F. , Bufferand H. , Ciraolo G. , Ghendrih P. , Serre E. , Tamain P. 
Published: January 2022

Abstract
In the present work we investigate for the first time the 2D fluid transport of the plasma in WEST during an entire discharge from the start-up to the ramp-down (shot #54487). The evolution of density profile, electron and ion temperatures together with the experimental magnetic equilibrium, total current and gas-puff rate is investigated. Comparisons with the interferometry diagnostic show a remarkable overall qualitative agreement during the discharge that can be quantitative at some locations in the plasma core. If at the onset of the X-points during the ramp-up the electron heat flux is dominant at the target, present results show that the ion heat flux becomes dominant during the stationary phase of the discharge. Using a simple model for erosion, present results assess the tungsten sputtering due to deuterium ions during the start-up and ramp-up phases of the discharge and confirm the need to consider full discharge simulation to accurately treat the W source of contamination. This work also demonstrates the interest of developing magnetic equilibrium free solver including efficient time integration to step toward predictive capabilities in the future for fusion operation.
Multi-contrast CT imaging using a high energy resolution CdTe detector and a CZT photon-counting detector
Authors: Clements N. , Richtsmeier D. , Hart A. , Bazalova-Carter M. 
Published: January 2022

Abstract
Computed tomography (CT) imaging with high energy resolution
detectors shows great promise in material decomposition and
multi-contrast imaging. Multi-contrast imaging was studied by
imaging a phantom with iodine (I), gadolinium (Gd), and gold (Au)
solutions, and mixtures of the three using a cadmium telluride
(CdTe) spectrometer with an energy resolution of 1% as well as with
a cadmium zinc telluride (CZT) detector with an energy resolution of
13%. The phantom was imaged at 120 kVp and 1.1 mA with 7 mm of
aluminum filtration. For the CdTe data collection, the phantom was
imaged using a 0.2 mm diameter x-ray beam with 96 ten-second data
acquisitions across the phantom at 45 rotation angles. For the CZT
detector, we had 720 projections using a cone beam, and the six
detector energy thresholds were set to 23, 33, 50, 64, 81, and
120 keV so that three thresholds corresponded to the K-edges of the
contrast agents. Contrast agent isolation methods were then
examined. K-edge subtraction and novel spectrometric algebraic image
reconstruction (SAIR) were used for the CdTe data. K-edge
subtraction alone was used for the CZT data. Linearity plots
produced similar R
2 values and slopes for all three
reconstruction methods. Comparing CdTe methods, SAIR offered less
noise than CdTe K-edge subtraction and better geometric accuracy at
low contrast concentrations. CdTe contrast agent images of I, Gd,
and Au offered less noise and greater contrast than the CZT images,
highlighting the benefits of high energy resolution CdTe detectors
for possible use in pre-clinical or clinical CT imaging.
Emptiness formation in polytropic quantum liquids
Authors: Yeh Hsiu-Chung , Gangardt Dimitri M , Kamenev Alex 
Published: January 2022

Abstract
We study large deviations in interacting quantum liquids with the polytropic equation of state P(ρ) ∼ ρ

γ
, where ρ is density and P is pressure. By solving hydrodynamic equations in imaginary time we evaluate the instanton action and calculate the emptiness formation probability (EFP), the probability that no particle resides in a macroscopic interval of a given size. Analytic solutions are found for a certain infinite sequence of rational polytropic indexes γ and the result can be analytically continued to any value of γ ⩾ 1. Our findings agree with (and significantly expand on) previously known analytical and numerical results for EFP in quantum liquids. We also discuss interesting universal spacetime features of the instanton solution.
Potential of nanoparticles and nanopolymers in treatment of age-associated diseases
Authors: Saadatpour Fatemeh , Mohammadipanah Fatemeh , Zohourian Nazanin , Hodjat Mahshid 
Published: January 2022

Abstract
Aging is an inevitable process caused by the accumulation of degenerative destructions, which ultimately leads to organism death. As the aging process occurs at the molecular, cellular, and tissue levels, understanding the whole details of age-related disorders is the prerequisite for the development of anti-aging therapy. More than 300 compounds of different sources have been reported with an anti-aging activity that controls age-related diseases through regulating single or multiple signalling pathways. Recent innovations in nanotechniques could lead to the development of nanomaterials having effects on age-associated malfunctions or acting as nanocarrier systems and distributers of anti-aging drugs. In this review, we summarised the molecular mechanisms of longevity and the prospect of developing anti-aging nanomaterials targeting aging pathways.
Photo de-mixing in mixed halide perovskites: the roles of ions and electrons
Authors: Wang Ya-Ru , Yeong Kim Gee , Kotomin Eugene , Moia Davide , Maier Joachim 
Published: January 2022

Abstract
Mixed halide perovskites have attracted great interest for applications in solar cells, light emitting diodes and other optoelectronic devices due to their tunability of optical properties. However, these mixtures tend to undergo de-mixing into separate phases when exposed to light (photo de-mixing), which compromises their operational reliability in devices. Several models have been proposed to elucidate the origin of the photo de-mixing process, including the contribution of strain, electronic carrier stabilization due to composition dependent electronic energies, and light induced ionic defect formation. In this perspective we discuss these hypotheses and focus on the importance of investigating defect chemical and ion transport aspects in these systems. We discuss possible optoionic effects that can contribute to the driving force of de-mixing and should therefore be considered in the overall energy balance of the process. These effects include the selective self-trapping of photo-generated holes as well as scenarios involving multiple defects. This perspective provides new insights into the origin of photo de-mixing from a defect chemistry point of view, raising open questions and opportunities related to the phase behavior of mixed halide perovskites.
Tumor Size, Not Small Vessel Invasion, Predicts Survival in Patients With Hepatocellular Carcinoma
Authors: Zhang Dongwei , Love Tanzy , Hao Yansheng , Liu Bella Lingjia , Thung Swan , Fiel Maria Isabel , Whitney-Miller Christa L , Liao Xiaoyan 
Published: January 2022

Abstract

Objectives
The 8th edition American Joint Committee on Cancer (AJCC) staging system for hepatocellular carcinoma (HCC) has been criticized for failing to stratify patients. We aimed to reassess and modify the tumor staging criteria for HCC.

Methods
Three independent study cohorts were collected and analyzed.

Results
The initial cohort consists of 103 patients with HCC. By Kaplan-Meier survival analysis, the 8th edition failed to distinguish between T1b and T2. Only tumor size and large vessel invasion, but not small vessel invasion or other histopathologic parameters, predicted HCC survival. We modified the T staging criteria by eliminating small vessel invasion while emphasizing tumor size in the middle categories (T2 and T3), which achieved more even distribution of cases and significantly improved risk stratifications (P &lt; .001). This modification was then validated in a cohort of 250 consecutive patients from Mount Sinai Hospital and an online Surveillance, Epidemiology, and End Results data set comprising 9,685 patients, which showed similar results. Small vessel invasion was not an independent prognostic factor in either validation cohort.

Conclusions
Our study showed that tumor size, but not small vessel invasion, predicts survival in patients with HCC. We suggest incorporating our modified T staging criteria in future AJCC revisions.
Rh(D) Alloimmunization Risk After Rh(D)-Incompatible Solid Organ Transplantations in Rh(D)-Negative Recipients
Authors: Ahn Ari , Yang John Jeongseok , Youk Hee Jeong , Cho Duck , Oh Heung-Bum , Ko Dae-Hyun , Hwang Sang-Hyun 
Published: January 2022

Abstract

Objectives
Rh(D)-incompatible (Rh-i) solid organ transplantations are not considered for organ matching, but no consensus guidelines exist regarding the need for anti-D immunoglobulin (RhIG) prophylaxis.

Methods
We reviewed 35 Rh(D)-negative patients who had received Rh-i solid organ transplantation. We divided the patients into a RhIG-administered group and a nonadministered group. All patients also underwent an antibody screening test to assess Rh alloimmunization. Graft function was monitored with serum creatinine or bilirubin and kidney or liver biopsy whenever a rejection was suspected. Overall survival was also assessed.

Results
The median (range) age of transplant recipients was 48.5 (4-69) years, and 73.5% of patients were male. Median (range) follow-up time after transplantation was 60 (2-246) months. In the RhIG nonadministered group (n = 16), anti-D was not detected in any of the patients. More rejection episodes occurred in the RhIG-administered group among those undergoing kidney transplant (P = .0278).

Conclusions
The low rate of Rh(D) alloimmunization is associated with the immunosuppressive state of the patients. RhIG prophylaxis seems to have no clinical benefit in Rh-i solid organ transplantation.
Effects of Renin–Angiotensin System Inhibitors on Mortality and Disease Severity of COVID-19 Patients: A Meta-analysis of Randomized Controlled Trials
Authors: Yin Juntao , Wang Chaoyang , Song Xiaoyong , Li Xiumin , Miao Mingsan 
Published: January 2022

AbstractBACKGROUNDThere is controversy over the effects of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) on the prognosis in patients with coronavirus disease 2019 (COVID-19), therefore, we aim to further explore the effect of renin–angiotensin–aldosterone system inhibitors on COVID-19-associated disease severity and mortality.METHODSWe systematically searched PubMed, Embase, Cochrane Library databases, medRxiv, and bioRxiv from inception to 6 September 2021. The primary outcome was all-cause mortality. Secondary outcome was severe disease which was defined as admission to the intensive care unit, the use of noninvasive or invasive mechanical ventilation, or death.RESULTSA total of 7 randomized controlled trials involving 1,321 COVID-19 patients were included. Fixed-effects meta-analysis demonstrated that the use of ACEI/ARB was not associated with higher risk of mortality (risk ratio [RR] = 0.84, 95% confidence interval [CI] 0.57–1.22, P = 0.10, I2 = 43%) and disease severity (RR = 0.86, 95% CI 0.71–1.05, P = 0.11, I2 = 47%). However, the subgroup analysis showed that compared with no ACEI/ARB use, the use of ARB was associated with a significant reduction of mortality (RR = 0.23, CI 0.09–0.60, P = 0.55, I2 = 0%) and disease severity (RR = 0.38, CI 0.19–0.77, P = 0.007).CONCLUSIONSIn conclusion, based on the available data, ACEI/ARB is not associated with the risk of mortality and disease severity in COVID-19 patients. And ACEI/ARB medications, especially ARB, should not be discontinued for patients with COVID-19.