bluuebunny/crossref_metadata_2025 huggingface dataset:
Research progress of asymmetrically coordinated single-atom catalysts for electrocatalytic reactions
Authors: Xu Wenjing , Tang Hao , Gu Hongfei , Xi Hongyan , Wu Pengfei , Liang Benliang , Liu Qingqing , Chen Wenxing
Published: June 2022

This review summarizes recent research progress on rationally designed single-atom catalysts with asymmetric coordination structures and their electrocatalytic applications.
Assembled caseins as crosslinkers for tough, adhesive and self-healing hydrogels towards flexible sensors
Authors: Li Xiao-Xia , Wang Min , Dai Jing , Liu Huanhuan , Qin Haili
Published: June 2022

Using casein-assembled nanostructures as crosslinkers, we developed hydrogels with remarkable mechanical performances, excellent adhesive, biocompatible and self-healing properties, demonstrating their potential applications as flexible sensors.
2D/3D heterostructured CsPbI2Br solar cells: a choice for a monolithic all-perovskite tandem device
Authors: Yan Liqiu , Li Yan , Li Siqi , Sun Xiangnan , Li Yao , Han Xue , Huang Meilan , Tao Xia
Published: June 2022

Improving the performance of CsPbI2Br PSCs by spinning BABr on 3D CsPbI2Br films to form 2D/3D heterostructures, and based on this, monolithic all-PTSCs are fabricated, realizing a pioneering exploration for the application of CsPbI2Br to all-PTSCs.
Pre- and post-assembly modifications of colloidal plasmonic arrays: the effect of size distribution, composition and annealing
Authors: Colomer-Ferrer Oriol , Toda Cosi Serni , Conti Ylli , Medina-Quiroz David E. , Scarabelli Leonardo , Mihi Agustin
Published: June 2022

Internal organization and composition of plasmonic colloidal array unit cells are engineered exploring both pre- and post- assembly modifications.
A nanoclay-confined single atom catalyst: tuning uncoordinated N species for efficient water treatment
Authors: Dong Xiongbo , Qian Yinyin , Chen Zitong , Jiang Zhiyi , Tang Aidong , Yang Huaming
Published: June 2022

Uncoordinated nitrogen species in a single atom catalyst accelerate the release of intermediates and the regeneration of active sites via downshifting its d-band center to a lower energy level.
Adversarial learning‐based multi‐timescale network resource management in multi‐mode green IoT network for smart building
Authors: Shi Cheng , Liu Pengju , Chen Yapeng , Zhou Zhenyu , Yang Junzhong , Zhao Chenkai , Chen Bei , Yang Sen , Mumtaz Shahid
Published: June 2022

Multi‐mode green internet of things (IoT) network that integrates multiple communication media can well meet data transmission and processing demands of low‐carbon smart building. However, network resource management optimisation including joint optimisation of gateway and channel selection still faces technical challenges such as differentiated quality of service (QoS) demand guarantee, coupling between optimisation problems with different timescales, and adversary caused by multi‐device competition. To address these challenges, an adversarial learning‐based multi‐timescale network resource management algorithm for multi‐mode green IoT is proposed. Specifically, the minimisation problem of weighted difference between energy consumption and throughput under the long‐term queuing delay constraints is formulated to achieve differentiated QoS guarantee. Large‐timescale gateway selection is decoupled from small‐timescale channel selection by establishing matching preferences based on empirical performance, and optimised by using bilateral matching with quota. Finally, an exponential‐weight algorithm for exploration and exploitation (EXP3)‐based small‐timescale channel selection algorithm is proposed to achieve adversary awareness. Simulation results demonstrate that compared with asynchronous greedy matching algorithm and auction‐based many‐to‐many matching algorithm, the proposed algorithm performs superior in terms of energy consumption and throughput.
Self‐supervised monocular depth estimation via asymmetric convolution block
Authors: Hu Lingling , Zhang Hao , Wang Zhuping , Huang Chao , Zhang Changzhu
Published: June 2022

Without the dependence of depth ground truth, self‐supervised learning is a promising alternative to train monocular depth estimation. It builds its own supervision signal with the help of other tools, such as view synthesis and pose networks. However, more training parameters and time consumption may be involved. This paper proposes a monocular depth prediction framework that can jointly learn the depth value and pose transformation between images in an end‐to‐end manner. The depth network creatively employs an asymmetric convolution block instead of every square kernel layer to strengthen the learning ability of extracting image features when training. During inference time, the asymmetric kernels are fused and converted to the original network to predict more accurate image depth, thus bringing no extra computations anymore. The network is trained and tested on the KITTI monocular dataset. The evaluated results demonstrate that the depth model outperforms some State of the Arts (SOTA) approaches and can reduce the inference time of depth prediction. Additionally, the proposed model performs great adaptability on the Make3D dataset.
Active contour model of breast cancer DCE‐MRI segmentation with an extreme learning machine and a fuzzy C‐means cluster
Authors: Feng Bao , Zhou Haoyang , Feng Jin , Chen Yehang , Liu Yu , Yu Tianyou , Liu Zhuangsheng , Long Wansheng
Published: June 2022

Due to the low contrast, blurred boundary and intensity inhomogeneity of the images, accurate segmentation of breast cancer lesions with dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) still has great challenges. This paper proposed an improved active contour model (ACM) for segmenting breast cancer lesions in DCE‐MRI images. First, based on the extreme learning machine (ELM) method, a robust function is proposed that combines image intensities and time‐domain features to enhance the difference between the lesions and other tissues. Second, an edge‐stop function (ESF) is introduced by combining the image intensity, time‐domain feature, and Hessian shape index to detect the irregular and blurred boundaries. At the boundary of breast cancer lesions, the energy function of ACM is minimized and the evolution of the contour curve completes, so the accurate lesion region of breast cancer can be segmented. The mean Dice similar coefficient (DICE), Jaccard similarity (JC) and Hausdorff distance (HD) of the segmentation of the proposed model in 50 samples are 85.88±6.62%, 75.72±9.68% and 11.62±4.72 mm, respectively. The results segmented by the proposed ACM are more similar to the manual segmentation than the compared models.
Toward fully compressible numerical simulations of stellar magneto-convection with the RAMSES code
Authors: Canivete Cuissa J. R. , Teyssier R.
Published: June 2022

Context. Numerical simulations of magneto-convection have greatly expanded our understanding of stellar interiors and stellar magnetism. Recently, fully compressible hydrodynamical simulations of full-star models have demonstrated the feasibility of studying the excitation and propagation of pressure and internal gravity waves in stellar interiors, which would allow for a direct comparison with asteroseismological measurements. However, the impact of magnetic fields on such waves has not been taken into account yet in three-dimensional simulations.

Aims. We conduct a proof of concept for the realization of three-dimensional, fully compressible, magneto-hydrodynamical numerical simulations of stellar interiors with the RAMSES code.

Methods. We adapted the RAMSES code to deal with highly subsonic turbulence, typical of stellar convection, by implementing a well-balanced scheme in the numerical solver. We then ran and analyzed three-dimensional hydrodynamical and magneto-hydrodynamical simulations with different resolutions of a plane-parallel convective envelope on a Cartesian grid.

Results. Both hydrodynamical and magneto-hydrodynamical simulations develop a quasi-steady, turbulent convection layer from random density perturbations introduced over the initial profiles. The convective flows are characterized by small-amplitude fluctuations around the hydrodynamical equilibrium of the stellar interior, which is preserved over the whole simulation time. Using our compressible well-balanced scheme, we were able to model flows with Mach numbers as low as ℳ ∼ 10−3, but even lower Mach number flows are possible in principle. In the magneto-hydrodynamical runs, we observe an exponential growth of magnetic energy consistent with the action of a small-scale dynamo. The weak seed magnetic fields are amplified to mean strengths of 37% relative to the kinetic equipartition value in the highest resolution simulation. Since we chose a compressible approach, we see imprints of pressure and internal gravity waves propagating in the stable regions above and beneath the convection zone. In the magneto-hydrodynamical case, we measured a deficit in acoustic and internal gravity wave power with respect to the purely hydrodynamical counterpart of 16% and 13%, respectively.

Conclusions. The well-balanced scheme implemented in RAMSES allowed us to accurately simulate the small-amplitude, turbulent fluctuations of stellar (magneto-)convection. The qualitative properties of the convective flows, magnetic fields, and excited waves are in agreement with previous studies in the literature. The power spectra, profiles, and probability density functions of the main quantities converge with resolution. Therefore, we consider the proof of concept to be successful. The deficit of acoustic power in the magneto-hydrodynamical simulation shows that magnetic fields must be included in the study of pressure waves in stellar interiors. We conclude by discussing future developments.
Pulsational instability of pre-main-sequence models from accreting protostars
Authors: Steindl T. , Zwintz K. , Müllner M.
Published: June 2022

Context. The physics of early stellar evolution (e.g. accretion processes) is often not properly included in the calculations of pre-main-sequence models, leading to insufficient model grids and hence systematic errors in the results.

Aims. We aim to investigate current and improved approaches for the asteroseismic modelling of pre-main-sequence δ Scuti stars.

Methods. We calculated an extensive grid of pre-main-sequence models including the early accretion phase and used the resulting equilibrium models as input to calculate theoretical frequency spectra. These spectra were used to investigate different approaches in modelling echelle diagrams to find the most reliable methods. By applying Petersen diagrams, we present a simple algorithm to extract echelle diagrams from observed pulsation frequencies.

Results. We show that model grids with insufficient input physics and imperfect modelling approaches lead to underestimated uncertainties and systematic errors in the extracted stellar parameters. Our re-discussion of HD 139614 leads to different stellar parameters than the ones derived by Murphy et al. (2021, MNRAS, 502, 1633). We performed a model comparison between this previous investigation and our results by applying the Akaike and Bayesian information criteria. While the results with regard to our ten-dimensional model are inconclusive, they show (very) strong evidence of a six-dimensional model with fixed accretion parameters (leading to almost identical stellar parameters to those of the ten-dimensional model) to be preferred over the model applied by Murphy et al. (2021, MNRAS, 502, 1633). In general, our modelling approach can provide narrow constraints on the stellar parameters (i.e. ΔR ∼ 0.05 R⊙, Δlog g ≲ 0.01, and ΔM⋆ ∼ 0.1 M⊙).

Conclusions. The extensively tested modelling approaches and automatic extraction of echelle diagrams should allow us to study many more pre-main-sequence δ Scuti stars in the future and lead to reliable stellar parameters.
System equivalent flux density of Stokes I, Q, U, and V of a polarimetric interferometer
Authors: Sutinjo A. T. , Ung D. C. X. , Sokolowski M.
Published: June 2022

Aims. We present the system equivalent flux density (SEFD) expressions for all four Stokes parameters: I, Q, U, and V.

Methods. The expressions were derived based on our derivation of SEFD I (for Stokes I) and subsequent extensions of that work to phased array and multipole interferometers. The key to the derivation of the SEFD Q, U, and V expressions is to recognize that the noisy estimates of Q, U, and V can be written as the trace of a matrix product. This shows that the SEFD I is a special case, where the general case involves a diagonal or anti-diagonal 2 × 2 matrix interposed in the matrix multiplication. Following this step, the relation between the SEFD for I as well as Q, U, and V immediately becomes evident.

Results. We present example calculations for a crossed dipole based on the formulas derived and the comparison between simulation and observation using the Murchison Widefield Array (MWA).
Wave blocking in a bistable system by local introduction of a population: application to sterile insect techniques on mosquito populations
Authors: Almeida Luís , Estrada Jorge , Vauchelet Nicolas
Published: June 2022

The Sterile Insect Technique (SIT) is a classic vector control method that has been successfully applied to fight against diverse insect plagues since the 1950s. In recent years, this strategy has been used to control mosquito populations, in order to limit the spread of the diseases they transmit. In this paper, we consider a system of reaction-diffusion equations to model the mosquito population and study the effect of the release of sterile mosquito males. Then, we propose to analyze the release in a limited area inside a wider area containing a natural mosquito population. We are interested in protecting a mosquito free region from invasion by mosquitoes from an exterior domain by controlling the population in a release band at the border between the two regions: we construct a barrier blocking the invasion of mosquitoes from the exterior. We adapt the geometric method of Lewis and Keener (see Lewis and Keener [SIAM J. Appl. Math. 61 (2000) 293-316]) in this framework and extend their main result to find relations on the size of the release region and the density of the released sterile males that allow us to block the invasion. Numerical simulations are also performed to illustrate our results.
Differenzierte Therapiestrategie bei Lebermetastasen gastro-entero-pankreatischer Neuroendokriner Neoplasien
Authors: Mogl Martina T. , Öllinger Robert , Jann Henning , Gebauer Bernhard , Fehrenbach Uli , Amthauer Holger , Wetz Christoph , Schmelzle Moritz , Raschzok Nathanael , Krenzien Felix , Goretzki Peter E. , Pratschke Johann , Schoening Wenzel
Published: June 2022

Neuroendokrine Neoplasien (NEN) bilden eine heterogene Gruppe maligner Tumoren, die überwiegend dem gastro-entero-pankreatischen System (GEP) zuzuordnen sind. Hierbei sind Dünndarm und
Pankreas die häufigsten Organe für Primärtumoren, die Leber stellt den dominanten Metastasierungsort dar. Da viele Patient*innen lange asymptomatisch bleiben, führen oftmals zufällig
diagnostizierte Lebermetastasen oder ein Ileus zur Diagnose. Die einzige kurative Therapieoption stellt die komplette Entfernung von Primarius und Metastasen dar. Besonders im Falle der
metastasierten Erkrankung sollten die vorhandenen Therapieoptionen immer im interdisziplinären Tumorboard mit Spezialisten*innen aus Gastroenterologie, (Leber-)Chirurgie, Radiologie,
Nuklearmedizin, Radiotherapie, Pathologie und Endokrinologie evaluiert werden. Durch die Kombination der verschiedenen Therapieverfahren kann auch für Patient*innen mit fortgeschrittener
Erkrankung eine jahrelange Prognose bei guter Lebensqualität erreicht werden. Wichtig für die Therapieentscheidung sind neben patientenindividuellen Faktoren der Differenzierungsgrad des
Tumors, dessen hormonelle Sekretion, das Metastasierungsmuster und der Erkrankungsverlauf. Die Behandlung von Lebermetastasen umfasst neben den unterschiedlichen chirurgischen Strategien die
lokal-ablativen radiologischen und nuklearmedizinischen Verfahren, die als Ergänzung zu den systemischen Therapien zur Verfügung stehen.
Risk scoring system for the preprocedural prediction of the clinical failure of peroral endoscopic myotomy: a multicenter case–control study
Authors: Abe Hirofumi , Tanaka Shinwa , Sato Hiroki , Shimamura Yuto , Okada Hiroki , Shiota Junya , Sato Chiaki , Sakae Hiroyuki , Ominami Masaki , Hata Yoshitaka , Fukuda Hisashi , Ogawa Ryo , Nakamura Jun , Tatsuta Tetsuya , Ikebuchi Yuichiro , Yokomichi Hiroshi , Inoue Haruhiro
Published: June 2022

Background Peroral endoscopic myotomy (POEM) is effective for the management of achalasia and its variants; however, it can be ineffective in some patients. We aimed to develop and validate a risk scoring system to predict the clinical failure of POEM preoperatively.

Methods Consecutive patients who underwent POEM in 14 high volume centers between 2010 and 2020 were enrolled in this study. Clinical failure was defined as an Eckardt score of ≥ 4 or retreatment. A risk scoring system to predict the short-term clinical failure of POEM was developed using multivariable logistic regression and internally validated using bootstrapping and decision curve analysis.

Results Of the 2740 study patients, 112 (4.1 %) experienced clinical failure 6 months after POEM. Risk scores were assigned for three preoperative factors as follows: preoperative Eckardt score (1 point), manometric diagnosis (−4 points for type II achalasia), and a history of prior treatments (1 point for pneumatic dilation or 12 points for surgical/endoscopic myotomy). The discriminative capacity (concordance statistics 0.68, 95 %CI 0.62–0.72) and calibration (slope 1.15, 95 %CI 0.87–1.40) were shown. Decision curve analysis demonstrated its clinical usefulness. Patients were categorized into low (0–8 points; estimated risk of clinical failure < 5 %) and high risk (9–22 points; ≥ 5 %) groups. The proportions of clinical failure for the categories were stratified according to the mid-term outcomes (log-rank test, P < 0.001).

Conclusions This risk scoring system can predict the clinical failure of POEM preoperatively and provide useful information when making treatment decisions.
Potential Contribution of Ultrasonography Assistance for the Safe and Steady Procedure of Endoscopic Intracerebral Hematoma Evacuation: A Retrospective Cohort Study
Authors: Kitamura Yuki , Kawaguchi Tomohiro , Uchida Hiroki , Endo Hidenori , Tominaga Teiji
Published: June 2022

Background Endoscopic hematoma evacuation is one of the most promising procedures for the treatment of intracerebral hemorrhage (ICH) to avoid severe outcomes, such as death or dependency. However, the effect of the procedure on the functional outcome remains controversial. Thus, standardization and sophistication are required to enhance the surgical results. This study aimed to evaluate the potential efficacy of ultrasonography (US) in endoscopic hematoma evacuation.

methods This study included 39 consecutive patients with spontaneous supratentorial ICH who underwent endoscopic hematoma evacuation between April 2019 and July 2021. The patients were divided into two groups, namely, surgery with or without US assistance. Rebleeding and evacuation rate were set as the primary endpoints, and operation time, requirement for repeat puncture, and modified Rankin scale at discharge were set as the secondary endpoints. During surgery, the burr hole was placed, and the dura mater was widely opened. The US probe was applied on the brain surface via the burr hole to detect the depth and direction of the hematoma cavity. With US assistance, the hematoma cavity was punctured with a cannula, and the transparent port was introduced into the hematoma cavity along the tract. The hematoma was gently evacuated with the irrigation–suction instrument.

Results Of the 39 cases, 9 underwent endoscopic hematoma evacuation with US assistance. Rebleeding was noted in 0 and 2 (6.7%) patients with and without US assistance, respectively (p = 0.43). The mean hematoma evacuation rates were 78.6 and 80.6% in patients with and without US assistance, respectively (p = 0.80). In all cases with US assistance, the cavity could be reached with a single tap. However, repeat puncture was required in 20 (66.7%) cases without US assistance (p = 0.04). In one case, an unexpected residual hematoma was detected using US, which was applied after hematoma evacuation and before wound closure. The operation time was not extended even if US was used during the surgery.

Conclusions US-assisted hematoma evacuation is an effective procedure that can assist in the precise insertion of the puncture cannula and exclusion of the residual hematoma. US might contribute toward improving the accuracy of each step of the procedure, thus leading to better clinical outcomes.
Physician Electronic Health Record Usage as Affected by the COVID-19 Pandemic
Authors: Ruan Elise , Beiser Moshe , Lu Vivian , Paul Soaptarshi , Ni Jason , Nazar Nijas , Liu Jianyou , Kim Mimi , Epstein Eric , Keller Marla , Kitsis Elizabeth , Tomer Yaron , Jariwala Sunit P.
Published: June 2022

Objectives To utilize metrics from physician action logs to analyze volume, physician efficiency and burden as impacted by telemedicine implementation during the COVID-19 (coronavirus disease 2019) pandemic, and physician characteristics such as gender, years since graduation, and specialty category.

Methods We selected 11 metrics from Epic Signal, a functionality of the Epic electronic health record (EHR). Metrics measuring time spent in the EHR outside working hours were used as a correlate for burden. We performed an analysis of these metrics among active physicians at our institution across three time periods—prepandemic and telehealth implementation (August 2019), postimplementation of telehealth (May 2020), and follow-up (July 2020)—and correlated them with physician characteristics.

Results Analysis of 495 physicians showed that after the start of the pandemic, physicians overall had fewer appointments per day, higher same day visit closure rates, and spent less time writing notes in the EHR outside 7 a.m. to 7 p.m. on patient scheduled days. Across all three time periods, male physicians had better EHR-defined “efficiency” measures and spent less time in the EHR outside working hours. Years since graduation only had modest associations with higher same day visit closure rates and appointments per day in May 2020. Specialty category was significantly associated with appointments per day and same day closure visit rates and also was a significant factor in the observed changes seen across the three time periods.

Conclusion Utilizing EHR-generated reports may provide a scalable and nonintrusive way to monitor trends in physician usage and experience to help guide health systems in increasing productivity and reducing burnout.
Nuclear mechanoprotection: From tissue atlases as blueprints to distinctive regulation of nuclear lamins
Authors: Wang Mai , Ivanovska Irena , Vashisth Manasvita , Discher Dennis E.
Published: June 2022

Two meters of DNA in each of our cells must be protected against many types of damage. Mechanoprotection is increasingly understood to be conferred by the nuclear lamina of intermediate filament proteins, but very different patterns of expression and regulation between different cells and tissues remain a challenge to comprehend and translate into applications. We begin with a tutorial style presentation of “tissue blueprints” of lamin expression including single-cell RNA sequencing in major public datasets. Lamin-A, C profiles appear strikingly similar to those for the mechanosensitive factors Vinculin, Yap1, and Piezo1, whereas datasets for lamin-B1 align with and predict regulation by the cell cycle transcription factor, FOXM1, and further predict poor survival across multiple cancers. Various experiments support the distinction between the lamin types and add mechanistic insight into the mechano-regulation of lamin-A, C by both matrix elasticity and externally imposed tissue strain. Both A- and B-type lamins, nonetheless, protect the nucleus from rupture and damage. Ultimately, for mechanically active tissue constructs and organoids as well as cell therapies, lamin levels require particular attention as they help minimize nuclear damage and defects in a cell cycle.
Drifts effect on the ordinary plasma wave and the existence of new spin dependent electron drift in the spin quantum plasma
Authors: Shahid M. , Usmani Sana , Iqbal Z. , Hussain A. , Bukhari Shujahat Hussain
Published: June 2022

Using a separated spin evolution quantum hydrodynamic model, we have derived generalized formula for drift effects of electrons in the inhomogeneous and nonuniform magnetized spin quantum plasma. We report, for the first time, the appearance of new spin dependent drift along with grad-B drift and diamagnetic drift. These results can be used to study the drift effects on various waves and instabilities. To check the applicability of our results, we have derived the dispersion relation of ordinary-mode (O-mode) incorporating electron spin, gradient in density, and magnetic field. We have studied various new features due to electron spin, perpendicular spin drifts, and grad B on the propagation of O-mode. Numerical analysis is presented for the choice of laboratory plasma parameters.
Momentum conservation in current drive and alpha-channeling-mediated rotation drive
Authors: Ochs Ian E. , Fisch Nathaniel J.
Published: June 2022

Alpha channeling uses waves to extract hot ash from a fusion plasma, transferring energy from the ash to the wave. It has been proposed that this process could create a radial electric field, efficiently driving E×B rotation. However, existing theories ignore the nonresonant particles, which play a critical role in enforcing momentum conservation in quasilinear theory. Because cross field charge transport and momentum conservation are fundamentally linked, this non-consistency throws the rotation drive into question. This paper has two main goals. First, we provide a pedantic and cohesive introduction to the recently developed simple, general, self-consistent quasilinear theory for electrostatic waves that explains the torques which allow for current drive parallel to the magnetic field, and charge extraction across it; a theory that has largely resolved the question of rotation drive by alpha channeling. We show how the theory reveals a fundamental difference between the reaction of nonresonant particles to plane waves that grow in time vs steady-state waves that have a nonuniform spatial structure, allowing rotation drive in the latter case while precluding it in the former, and we review the local and global conservation laws that lead to this result. Second, we provide two new results in support of the theory. First, we provide a novel two-particle Hamiltonian model that rigorously establishes the relationship between charge transport and momentum conservation. Second, we compare the new quasilinear theory to the oscillation-center theories of ponderomotive forces, showing how the latter often obscure the time-dependent nonresonant recoil, but ultimately lead to similar results.
Guidelines for attaining optimal soft magnetic properties in FeAlSi films
Authors: Akamatsu Shoma , Oogane Mikihiko , Tsunoda Masakiyo , Ando Yasuo
Published: June 2022

Nm-order FeAlSi epitaxial films with a partially D03-ordered structure were grown on MgO substrates, and ideal soft magnetic properties were obtained. We found that the sign of the magnetocrystalline anisotropy constant K1 changes with increasing annealing temperature for certain FeAlSi compositions. This is caused by a change in the volume balance of the ordered phases with the annealing process and the point at which K1 ∼ 0 shifts to the Al-rich concentration as the degree of D03-ordering decreases. K1 was precisely measured by ferromagnetic resonance under the optimal condition, and the value of 1.6 × 102 (erg/cc) was obtained, which is comparable to that of bulk. The uniaxial component of the magnetic anisotropy due to magnetostriction was small, and a fourfold symmetric component due to magnetocrystalline anisotropy was dominant.
On the Cartan decomposition for classical random matrix ensembles
Authors: Edelman Alan , Jeong Sungwoo
Published: June 2022

We complete Dyson’s dream by cementing the links between symmetric spaces and classical random matrix ensembles. Previous work has focused on a one-to-one correspondence between symmetric spaces and many but not all of the classical random matrix ensembles. This work shows that we can completely capture all of the classical random matrix ensembles from Cartan’s symmetric spaces through the use of alternative coordinate systems. In the end, we have to let go of the notion of a one-to-one correspondence. We emphasize that the KAK decomposition traditionally favored by mathematicians is merely one coordinate system on the symmetric space, albeit a beautiful one. However, other matrix factorizations, especially the generalized singular value decomposition from numerical linear algebra, reveal themselves to be perfectly valid coordinate systems that one symmetric space can lead to many classical random matrix theories. We establish the connection between this numerical linear algebra viewpoint and the theory of generalized Cartan decompositions. This, in turn, allows us to produce yet more random matrix theories from a single symmetric space. Yet, again, these random matrix theories arise from matrix factorizations, though ones that we are not aware have appeared in the literature.
Micro-magnetoelastic modeling of Terfenol-D for spintronics
Authors: De Jesús Michael Guevara , Panduranga Mohanchandra K. , Shirazi Paymon , Keller Scott , Jackson Malcolm , Wang Kang L. , Lynch Christopher S. , Carman Gregory P.
Published: June 2022

This article focuses on computational studies evaluating the influence of crystallinity, residual stresses, and out-of-plane (OOP) deterministic switching on Terfenol-D nano/microstructures. The computational models use both coupled and uncoupled Landau–Liftshitz–Gilbert equations with elastodynamics to study strain-induced magnetization reorientation. A Voronoi tessellation approach models the crystal distribution in the microstructures subjected to residual stresses with good agreement to experimental data including large changes in coercivity values, i.e., from 100 to 3000 Oe. Parametric studies show how the coercivity is manipulated with residual stresses, including a magnetoelastically induced perpendicular-magnetic-anisotropy (PMA), important for memory applications. Additional parametric studies focus on epitaxially deposited micro-disks, revealing that residual stresses can create magnetoelastically dominant easy axes along the ⟨110⟩ directions, which are energetically favorable relative to the intrinsic ⟨111⟩ magnetocrystalline easy axes. Modification of the global easy axis is used to design a strain-mediated multiferroic composite consisting of a 20 nm epitaxially deposited Terfenol-D memory bit with PMA grown on a PZT substrate. The multiferroic disk achieves OOP deterministic clocking with an applied voltage.
A magnetic actuation scheme for nano-kirigami metasurfaces with reconfigurable circular dichroism
Authors: Chen Yingying , Liang Qinghua , Ji Chang-Yin , Liu Xing , Wang Rongyao , Li Jiafang
Published: June 2022

Nano-kirigami-based deformable metasurfaces offer unique advantages in the dynamic modulation of optical fields and the realization of reconfigurable micro-/nano-optoelectronic devices. Here, we theoretically propose and numerically demonstrate a magnetically actuated deformation scheme for 2D nano-kirigami structures, which can be accurately and continuously transformed from 2D to 3D. Based on the traditional pinwheel structure, an Fe/Au bilayer anti-pinwheel nanostructure is designed and dynamically transformed by employing magnetic attraction in numerical simulations, in which the ratio between deformation height and lateral period could reach up to 0.563. More importantly, it is found that the anti-pinwheel structure has superior circular dichroism (CD), whose maximum CD response could reach 7 times that of the corresponding pinwheel structure. Further analysis of the scattering power of multipole moments reveals that such a superior CD response is found to be induced by the handedness-dependent excitation of a toroidal dipole moment. Such a straightforward magnetically actuated deformation and novel anti-pinwheel structure provides useful methodologies to explore and realize deformable metamaterials and their dynamic regulation capabilities, as well as applications in chiral spectroscopy, optical reconfiguration, optical sensing, etc.
Field-induced migration of gold in molecular semiconductors
Authors: Riederer P. , Bouraoui M. , Kersting R.
Published: June 2022

We report on the degradation of field-effect devices due to the migration of gold from injection contacts into the channel region. The experimental results are obtained by THz spectroscopy on devices with a migration distance of 50 nm. The dependence of the degradation on gate voltage, as well as the partial reversibility, indicates that degradation is caused by field-induced transport of gold ions. The transport is found to be thermally activated with an activation energy independent of the field strength, which suggests that lattice deformations of the molecular semiconductor support the migration of gold.
Structural dynamics of light harvesting proteins, photosynthetic membranes, and cells observed by spectral editing solid-state NMR
Authors: Pandit Anjali
Published: June 2022

Photosynthetic light-harvesting complexes have a remarkable capacity to perform robust photo-physics at ambient temperatures and in fluctuating environments. Protein conformational dynamics and membrane mobility are processes that contribute to the light-harvesting efficiencies and control photoprotective responses. This short review describes the application of magic angle spinning nuclear magnetic resonance (NMR) spectroscopy for characterizing the structural dynamics of pigment, protein, and thylakoid membrane components related to light harvesting and photoprotection. I will discuss the use of dynamics-based spectral editing solid-state NMR for distinguishing rigid and mobile components and assessing protein, pigment, and lipid dynamics on sub-nanosecond to millisecond timescales. Dynamic spectral editing NMR has been applied to investigate light-harvesting complex II protein conformational dynamics inside lipid bilayers and in native membranes. Furthermore, we used the NMR approach to assess thylakoid membrane dynamics. Finally, it is shown that dynamics-based spectral editing NMR for reducing spectral complexity by filtering motion-dependent signals enabled us to follow processes in live photosynthetic cells.
Numerical investigation on the characteristics of single droplet deformation in the airflow at different temperatures
Authors: Bian Qingyong , Zhu Chengxiang , Wang Jingxin , Zhao Ning , Zhao Huanyu , Zhu Chunling
Published: June 2022

Micro-sized droplets in air may impact aircraft wings and induce severe ice accretion. The deformation and acceleration of a single droplet in a continuous airflow are simulated using the multiphase lattice Boltzmann flux solver to compute the flow field, and the phase-field method is used to track the droplet–air interface. The effects of droplet size, airflow velocity, and ambient temperature on the morphological evolution, flow field structure, and droplet motion are analyzed. The results indicate that the deformation of the droplet increases with Weber number, which distinguishes different deformation modes. With the increase in the droplet size and airflow velocity, the deformation of the droplet becomes greater in less time, and the characteristic alternate compressions in the axial and radial directions disappear. Moreover, different subzero temperatures have little effect on the droplet acceleration despite a different deformation amplitude, while the droplet acceleration is attenuated at normal temperatures.
Narrow electroluminescence in bromide ligand-capped cadmium chalcogenide nanoplatelets
Authors: Thung Yi Tian , Zhang Zitong , Yan Fei , Demir Hilmi Volkan , Sun Handong
Published: June 2022

Colloidal zinc blende II–VI semiconductor nanoplatelets (NPLs) demonstrate as a promising class of materials for optoelectronic devices due to their unique excitonic characteristics, narrow emission linewidth, and quantum well-structure. Adopting heterostructures for these nanocrystals allows tuning of their optical features and enhances their photostability, photoluminescence (PL), quantum yield (QY), and color purity for further device integration. Exchanging of carboxylate capping ligands on top and bottom [001] facets of CdSe NPLs with halide ligands is an alternative to achieve the aims of spectral tunability and improve surface passivation, but to date there have been no reports on integrating the advantages of halide ligand exchanged CdSe NPLs for device fabrication. In this work, we demonstrate green electroluminescence (EL) of bromide ligand-capped CdSe NPLs as active emitters in an electrically driven light emitting diode (LED) with a low turn-on voltage of 3.0 V. We observed EL emission at 533.1 nm with a narrow linewidth of 19.4 nm, a maximum luminance of 1276 cd/m2, and the highest external quantum efficiency (EQE) of 0.803%. These results highlight the ability of halide ligand exchange in tuning the EL properties of CdSe NPL-LEDs and potential of bromide ligand-capped CdSe NPLs in contributing to the green emission region of NPL-LEDs, demonstrating its potential for future device integration and contribution to a high color rendering index of future NPL displays.
Second-harmonic generation in germanium-on-insulator from visible to telecom wavelengths
Authors: Wang Yadong , Burt Daniel , Lu Kunze , Nam Donguk
Published: June 2022

The second-order χ(2) process underpins many important nonlinear optical applications in the field of classical and quantum optics. Generally, the χ(2) process manifests itself only in a non-centrosymmetric dielectric medium via an anharmonic electron oscillation when driven by an intense optical field. Due to inversion symmetry, group-IV semiconductors, such as silicon (Si) and germanium (Ge), are traditionally not considered as ideal candidates for second-order nonlinear optics applications. Here, we report the experimental observation of the second-harmonic generation (SHG) in a Ge-on-insulator (GOI) sample under femtosecond optical pumping. We especially, report the measurement of the SHG signal from a GOI sample in the telecom S-band by pumping at ∼3000 nm.
Optical absorption spectra of MgO single crystals under shock compression between 50 and 132 GPa
Authors: Liu Qiancheng , Xue Tao , Li Jun , Li Jiabo , Zhou Xianming
Published: June 2022

Optical properties of transparent windows at high pressures are of essential importance in dynamic experiments. To investigate the effects of plastic deformation-induced defects on optical transparency of MgO single crystals, real-time absorption spectra are measured via impact experiments and fast multi-color pyrometry. Shock pressure ranges from 50 to 132 GPa. Optical transmission histories are measured in each experiment via an on-board light source generated by shock-wave, from which absorption coefficient α is determined as a function of the wavelength λ. The resultant real-time absorption spectrum (α vs λ) peaks around 520 nm (∼2.39 eV), which blueshifts with increasing pressure. These featured spectra are possibly attributed to defective absorption at defect-centers (color-centers) in MgO single crystals generated by shock-waves. Plasticity-induced defects are most likely responsible for the decrease in transparency. MgO single crystals are not suited to be used as an optical window for thermometric in the visible light spectrum under shock pressures above 129 GPa.
Multiple magnetic droplet solitions from exotic spin–orbit torques
Authors: Klause Robin , Hoffmann Axel
Published: June 2022

Materials with large spin–orbit interactions generate pure spin currents with spin polarizations parallel to the interfacial surfaces that give rise to conventional spin–orbit torques. These spin–orbit torques can only efficiently and deterministically switch magnets with in-plane magnetization. Additional symmetry breaking, such as in non-collinear antiferromagnets, can generate exotic, unconventional spin–orbit torques that are associated with spin polarizations perpendicular to the interfacial planes. Here, we use micromagnetic simulations to investigate whether such exotic spin–orbit torques can generate magnetic droplet solitions in out-of-plane magnetized geometries. We show that a short, high current pulse followed by a lower constant current can nucleate and stabilize magnetic droplets. Through specific current pulse lengths, it is possible to control the number of droplets in such a system, since torques are generated over a large area. Additionally, the nucleation current scales with the out-of-plane component of the spin polarization and is linear as a function of magnetic field strength.
26S proteasomes become stably activated upon heat shock when ubiquitination and protein degradation increase
Authors: Lee Donghoon , Goldberg Alfred L.
Published: June 2022

Heat shock (HS) promotes protein unfolding, and cells respond by stimulating HS gene expression, ubiquitination of cell proteins, and proteolysis by the proteasome. Exposing HeLa and other cells to 43 °C for 2 h caused a twofold increase in the 26S proteasomes’ peptidase activity assayed at 37 °C. This increase in activity occurred without any change in proteasome amount and did not require new protein synthesis. After affinity-purification from HS cells, 26S proteasomes still hydrolyzed peptides, adenosine 5′-triphosphate, and ubiquitinated substrates more rapidly without any evident change in subunit composition, postsynthetic modification, or association with reported proteasome-activating proteins. After returning HS cells to 37 °C, ubiquitin conjugates and proteolysis fell rapidly, but proteasome activity remained high for at least 16 h. Exposure to arsenite, which also causes proteotoxic stress in the cytosol, but not tunicamycin, which causes endoplasmic reticulum stress, also increased ubiquitin conjugate levels and 26S proteasome activity. Although the molecular basis for the enhanced proteasomal activity remains elusive, we studied possible signaling mechanisms. Proteasome activation upon proteotoxic stress required the accumulation of ubiquitinated proteins since blocking ubiquitination by E1 inhibition during HS or arsenite exposure prevented the stimulation of 26S activity. Furthermore, increasing cellular content of ubiquitin conjugates at 37 °C by inhibiting deubiquitinating enzymes with RA190 or b-AP15 also caused proteasome activation. Thus, cells respond to proteotoxic stresses, apparently in response to the accumulation of ubiquitinated proteins, by activating 26S proteasomes, which should help promote the clearance of damaged cell proteins.
Denitrification in foraminifera has an ancient origin and is complemented by associated bacteria
Authors: Woehle Christian , Roy Alexandra-Sophie , Glock Nicolaas , Michels Jan , Wein Tanita , Weissenbach Julia , Romero Dennis , Hiebenthal Claas , Gorb Stanislav N. , Schönfeld Joachim , Dagan Tal
Published: June 2022

Benthic foraminifera are unicellular eukaryotes that inhabit sediments of aquatic environments. Several foraminifera of the order Rotaliida are known to store and use nitrate for denitrification, a unique energy metabolism among eukaryotes. The rotaliidGlobobuliminaspp. has been shown to encode an incomplete denitrification pathway of bacterial origin. However, the prevalence of denitrification genes in foraminifera remains unknown, and the missing denitrification pathway components are elusive. Analyzing transcriptomes and metagenomes of 10 foraminiferal species from the Peruvian oxygen minimum zone, we show that denitrification genes are highly conserved in foraminifera. We infer the last common ancestor of denitrifying foraminifera, which enables us to predict the ability to denitrify for additional foraminiferal species. Additionally, an examination of the foraminiferal microbiota reveals evidence for a stable interaction with Desulfobacteraceae, which harbor genes that complement the foraminiferal denitrification pathway. Our results provide evidence that foraminiferal denitrification is complemented by the foraminifera-associated microbiome. The interaction of foraminifera with their resident bacteria is at the basis of foraminiferal adaptation to anaerobic environments that manifested in ecological success in oxygen depleted habitats.
Probing phonon dynamics with multidimensional high harmonic carrier-envelope-phase spectroscopy
Authors: Neufeld Ofer , Zhang Jin , De Giovannini Umberto , Hübener Hannes , Rubio Angel
Published: June 2022

We explore pump-probe high harmonic generation (HHG) from monolayer hexagonal-boron-nitride, where a terahertz pump excites coherent optical phonons that are subsequently probed by an intense infrared pulse that drives HHG. We find, through state-of-the-art ab initio calculations, that the structure of the emission spectrum is attenuated by the presence of coherent phonons and no longer comprises discrete harmonic orders, but rather a continuous emission in the plateau region. The HHG yield strongly oscillates as a function of the pump-probe delay, corresponding to ultrafast changes in the lattice such as specific bond compression or stretching dynamics. We further show that in the regime where the excited phonon period and the pulse duration are of the same order of magnitude, the HHG process becomes sensitive to the carrier-envelope phase (CEP) of the driving field, even though the pulse duration is so long that no such sensitivity is observed in the absence of coherent phonons. The degree of CEP sensitivity versus pump-probe delay is shown to be a highly selective measure for instantaneous structural changes in the lattice, providing an approach for ultrafast multidimensional HHG spectroscopy. Remarkably, the obtained temporal resolution for phonon dynamics is ∼1 femtosecond, which is much shorter than the probe pulse duration because of the inherent subcycle contrast mechanism. Our work paves the way toward routes of probing phonons and ultrafast material structural changes with subcycle temporal resolution and provides a mechanism for controlling the HHG spectrum.
A diachronic corpus-driven study of fansubbing
Authors: Taghavi Morteza , Bahraman Mostafa
Published: June 2022

What is of interest here is whether subtitling community in a country changes over time. Particularly, by taking a diachronic approach to AVT, the present paper attempts to investigate the degree of conformity of Iranian fansubbers to professional subtitle presentation standards to see if any change has happened in the behavior and characteristics of Iranian fansubbing community over time. To this end, we developed a diachronic corpus of subtitles consisting of 50 films belonging to 2008 and 2018, a decade later, to gauge variations (violations) from a set of standards. The findings suggest that generally fansubbers, although possibly unconsciously, show a higher degree of conformity to professional subtitle presentation standards over time. Concludingly, the fan AVT in Iran, in the corpus under investigation, has evolved in terms of professionalism. Finally, the changes seen in the community can call for some possible modifications required to update or revise the present standards.