bluuebunny/crossref_metadata_2025 huggingface dataset:
The influence of the adiabatic index on the radiation dynamics of self-similar expanding laser-produced plasma plume
Authors: Marenkov E. D. , Sinelnikov D. N. , Efimov N. E. , Bulgadaryan D. G. , Gasparyan Yu. M.
Published: January 2022

The radiation dynamics of an adiabatic self-similar expanding spherical plasma plume is considered. It is shown that the radiation intensities evolution strongly depends on the adiabatic index γ. For example, it is proven that the radiation intensity in a highly ionized plasma plume increases over time if γ = 5/3 and has a minimum in time if γ < 5/3. The analytical results are compared to measurements of the radiation from lithium laser-produced plasma. A lithium sample was irradiated by a powerful (42 J/cm2) laser pulse, and radiation of produced lithium plasma was registered by a monochromator. Reasonable agreement with the experiments is reached for γ = 5/4.
Perspective on 2D material polaritons and innovative fabrication techniques
Authors: Karanikolas Vasilios , Suzuki Seiya , Li Shisheng , Iwasaki Takuya
Published: January 2022

In this Perspective, we present that polariton modes hosted in two-dimensional (2D) materials can be used to increase and control light–matter interactions at the nanoscale. We analyze the optical response of the most used 2D material nanostructures that support plasmon, exciton, and phonon polariton modes. Polariton characteristic lengths are used to assess the hybrid light–matter modes of different 2D material monolayers and nanoribbons. We present that the 2D material nanodisk can act like a cavity that supports localized polariton modes, which can be excited by a nearby placed quantum system to present ultra-fast and ultra-bright operation. The key to achieve high quality 2D polariton modes is to reduce material losses. Thus, state-of-the-art exfoliation, chemical vapor deposition, and transferring techniques of 2D materials are introduced to fabricate nanostructures that fulfill the stringent requirements of applications in photonics, optoelectronics, and quantum technologies.
Tunable triple-band millimeter-wave absorbing metasurface based on nematic liquid crystal
Authors: Wang Qiang , Liu Yuan Ke , Wang Gui Chen , Jiang Wei Xiang , Cui Tie Jun
Published: January 2022

We propose and design a tunable triple-band millimeter-wave absorbing metasurface based on nematic liquid crystal (NLC). Numerical results based on both effective circuit model and full-wave simulations verify the triple-band absorption property. All triple absorption peaks can be shifted by changing the bias voltage applied to the nematic liquid crystal. We fabricate and measure a triple-band absorbing metasurface sample, which covers 100 × 100 mm2 and is composed of 20 × 20 unit cells. In experiments, when no bias voltage is applied to the NLC layer, the resonant frequencies of the absorbing metasurface are 25.4, 28.7, and 32.8 GHz, respectively. When a 5-V bias voltage is applied, all the absorbing peaks redshift, and a frequency tunability range of 9.5%, 9.1%, and 8.58% is observed in three resonant frequencies, respectively. The experimental results are in good agreement with the numerical simulations. The proposed tunable absorbing metasurface provides a way forward for the realization of tunable millimeter-wave metasurface devices that can be applied in multi-band detection and imaging.
Band convergence and phonon engineering to optimize the thermoelectric performance of CaCd2Sb2
Authors: Zhang Zongwei , Yao Honghao , Jia Xue , Wang Xinyu , Li Xiaofang , Chen Chen , Lin Xi , Sui Jiehe , Liu Xingjun , Mao Jun , Xie Guoqiang , Zhang Qian
Published: January 2022

Alignment of valence bands has been demonstrated to be effective in promoting the thermoelectric performance of p-type AB2X2 zintl phases. In this work, the degeneracy of the valence bands is manipulated by alloying CaCd2Sb2 with CaMg2Sb2. It is found that the Γ(pxy) band and the Γ(pz) band were effectively converged in CaCd1.5Mg0.5Sb2. By further doping Ag at the Cd site, the carrier concentration can be maintained when the alloying concentration varies. The room-temperature Seebeck coefficient increased from ∼150 μV K−1 in CaCd2Sb2 to ∼190 μV K−1 in CaCd1.5Mg0.5Sb2 when the carrier concentration was maintained at ∼2.5 × 1019 cm−3. In addition, Cd/Mg substitutional point defects with substantial atomic mass difference induced significant phonon scattering; thus, a lattice thermal conductivity as low as ∼0.5 W m−1 K−1 was achieved at 750 K. Eventually, a peak zT value of ∼1.3 was realized in CaCd1.494Ag0.006Mg0.5Sb2.
Lateral terahertz wave emission from laser induced plasma in liquid water line
Authors: Chen Yuxuan , He Yuhang , Tian Zhen , Dai Jianming
Published: January 2022

Laser ionized liquid has been considered as a promising broadband terahertz (THz) source recently. The ponderomotive force induced dipole model can be used to describe the mechanism of THz generation, implying that the lateral THz emission is stronger than the forward emission. Thus, we systemically investigate the lateral THz emission from laser induced plasma in liquid water line. THz energy about 4.4-times of that from the forward emission is achieved from the lateral emission scheme. Results on the angular distribution of coherent THz radiation indicate that the maximal THz radiation falls between 120° and 150° with respect to the pump laser propagation direction. Moreover, dependence of collected THz energy on the relative position between laser focus and the water line shows a counterintuitive “two peaks” trend, which can be explained by the impact of cylindrical water surface on the divergence angle of the generated THz wave. Therefore, the enhancement in THz energy can be attributed to the high-efficiency lateral collection scheme and the tradeoff between the THz wave converging effect of the cylindrical surface and the absorption in water. Our work helps to further optimize the coupling efficiency of generated THz wave out of liquid samples.
Study on characteristics of fragment size distribution generated via droplet breakup by high-speed gas flow
Authors: Kamiya Tomohiro , Asahara Makoto , Yada Tokiha , Mizuno Kyohei , Miyasaka Takeshi
Published: January 2022

In a design of scramjet engine using liquid hydrocarbon fuels, predictions of the fragment size distribution generated by liquid droplet breakup in high-speed gas flow are useful. However, the characteristics of fragment size distribution may be unclear, especially in high-velocity flows. In this study, the diameter of fragments formed by the disintegration of water droplets in a high-speed gas flow behind the shock wave was measured. The fragment diameters of several μm to several tens of μm moving at high speeds were clearly captured via high resolution visualization using a microscope and pulse laser with a flash time of 20 ns as a backlight. The parameters used to measure the fragment diameter from the captured images were determined from calibration experiments using a device that can change the working distance; thus, highly reliable particle size measurements were conducted. From the experimental results, the time variation in the volume probability density distribution of fragments size, Sauter mean diameter (SMD), and mass median diameter (MMD) were calculated. As a result, it was clarified that the volume probability density was successfully described by a root-normal distribution for high Weber number, for which catastrophic breakup should occur according to conventional classification. It was also observed that SMD and MMD increase with time, and the ratio of MMD to SMD was found to be 1.2, except at the initial stage. In this study, the characteristics of size distribution of the fragments generated by liquid droplet breakup in high-velocity flows, which was unclear, has been clarified.
Spin Seebeck effect in quantum magnet Pb2V3O9
Authors: Xing Wenyu , Cai Ranran , Moriyama Kodai , Nara Kensuke , Yao Yunyan , Qiao Weiliang , Yoshimura Kazuyoshi , Han Wei
Published: January 2022

The spin Seebeck effect (SSE), the generation of spin current from heat, has been extensively studied in a large variety of magnetic materials, including ferromagnets, antiferromagnets, paramagnets, and quantum spin liquids. In this paper, we report the study of the SSE in the single crystalline Pb2V3O9, a spin-gapped quantum magnet candidate with quasi-one-dimensional spin-1/2 chain. Detailed temperature and magnetic field dependences of the SSE are investigated, and the temperature-dependent critical magnetic fields show a strong correlation to the Bose–Einstein condensation phase of the quantum magnet Pb2V3O9. This work shows the potential of using spin current as a probe to study the spin correlation and phase transition properties in quantum magnets.
Experimental verification of semimetallic band structure in PtSe2 via thermoelectric power measurements
Authors: Kim Jeongmin , Youn Seonhye , Bang Joonho , Moon Hongjae , Jang Woosun , Roh Jong Wook , Kim Dong Hwan , Chang Joonyeon , Lee Wooyoung
Published: January 2022

This study presents an investigation of the band structure in a semimetallic two-dimensional (2D) PtSe2 nanosheet based on thermoelectric transport phenomena. Mechanically exfoliated PtSe2 nanosheets, including naturally doped nonneutral samples, were studied. The gate-tuned electrical conductivity and thermoelectric power were measured by varying the temperature. Based on the combined effects of gate-tuning and shifting of zero-gate energy level, the semimetallic band structure of 2D PtSe2 was confirmed in the band over a wide energy range. Furthermore, the temperature dependence of transport properties was investigated to determine the band structure and intrinsic properties.
Two-component density functional theory for muonic molecules: Inclusion of the electron–positive muon correlation functional
Authors: Goli Mohammad , Shahbazian Shant
Published: January 2022

It is well-known experimentally that the positively charged muon and the muonium atom may bind to molecules and solids, and through muon’s magnetic interaction with unpaired electrons, valuable information on the local environment surrounding the muon is deduced. Theoretical understanding of the structure and properties of resulting muonic species requires accurate and efficient quantum mechanical computational methodologies. In this paper, the two-component density functional theory (TC-DFT), as a first principles method, which treats electrons and the positive muon on an equal footing as quantum particles, is introduced and implemented computationally. The main ingredient of this theory, apart from the electronic exchange–correlation functional, is the electron–positive muon correlation functional that is foreign to the purely electronic DFT. A Wigner-type local electron–positive muon correlation functional, termed eμc-1, is proposed in this paper and its capability is demonstrated through its computational application to a benchmark set of muonic organic molecules. The TC-DFT equations containing eμc-1 are not only capable of predicting the muon’s binding site correctly, but they also reproduce muon’s zero-point vibrational energies and the muonic densities much more accurately than the TC-DFT equations lacking eμc-1. Thus, this study sets the stage for developing accurate electron–positive muon functionals, which can be used within the context of the TC-DFT to elucidate the intricate interaction of the positive muon with complex molecular systems.
Validation of theoretical analysis of surface bending strain in polymer films by surface-labeled grating method
Authors: Taguchi Ryo , Fujisawa Aki , Kishino Masayuki , Kuwahara Kohei , Akamatsu Norihisa , Fukuhara Motoyuki , Shishido Atsushi
Published: January 2022

Quantitative analysis of tension and compression imposed on surfaces of bending polymer films plays a key role in the design of flexible electronic devices. For over a decade, the analysis has relied on the classical beam theory that mainly deals with metals, glass, and cement; however, the applicable limit of the theory to largely bending polymer films has never been validated. We present that the classical beam theory accurately analyzes surface bending strains in single-layer and double-layer polymer films through measuring the strains by a surface-labeled grating method. The experimental analysis reveals that the bending strains on the outer and inner surfaces of the single-layer film are symmetrical, whereas those of the double-layer film are asymmetrical. These results are well explained by the classical beam theory considering stress–strain curves of polymer films. This approach will further advance the strain design of polymer films, which aids in the development of mechanically durable devices.
Reactive species created in the collapse of laser-induced cavitation bubbles: Generation mechanism and sensitivity analysis
Authors: Peng Kewen , Qin Frank G. F. , Jiang Runhua , Qu Wanjun , Wang Qianxi
Published: January 2022

Reactive species (RS) play a critical role in postoperative complications in the medical application of lasers. From the mechanistic point, the RS arising from laser irradiation are produced from two channels: ionization and dissociation of water in the breakdown plasma, and the violent collapse of the laser-induced cavitation bubble. The latter channel is especially important for nanosecond pulses but poorly understood. In this paper, we conducted a simulation of the chemical reactions coupled with bubble dynamic calculation to quantitatively identify the RS produced in the collapsing bubble. The generation mechanism is explored by the analysis of the reaction pathway. Our calculation shows that while the absolute quantity of the produced RS is small, very high concentrations can be achieved inside the strongly compressed bubble. The initial composition of the bubble recovered from plasma recombination and expansion is found to influence the chemical reactions significantly. Unlike the direct splitting of water molecules in radiolysis and photolysis, the RS productions mainly involve the decomposition of hydrogen peroxide and the reactions between hydrogen, oxygen, and various free radicals. Furthermore, the produced RS is observed to increase with pulse energy as a result of the larger-sized bubbles and more violent collapses. These findings complement our current knowledge of RS in laser surgery and can be used to develop strategies to mitigate the adverse effects or exploit the associated benefits.
Experimental performance of a small solar system for adsorption cooling in summer and heating in winter
Authors: Liu Yimo , Yuan Zhongxian , Liu Zhongbao
Published: January 2022

Solar energy is a kind of renewable energy with abundant resources and enormous reserves. Meanwhile, adsorption cooling technology can utilize natural refrigerants, thus also making this technology environmentally friendly. If solar energy can be effectively collected and utilized for heating in winter, then the environmental pollution caused by electricity and fossil energy consumption can be reduced. More importantly, considering engineering, the same solar device could provide cooling in the summer and heating in the winter. This study used parabolic trough and glass–metal vacuum heat collectors to conduct solar adsorption cooling and solar air heating experiments in summer and winter, respectively, to facilitate the complete and appropriate use of solar energy. Experimental results of solar adsorption cooling with silica gel as the adsorbent revealed that the coefficient of performance of the system reached 0.329. In addition, the influences of air flow rates and heat storage medium on the performance of the solar air heating system were investigated. Results revealed that the average and instantaneous efficiencies of the system considerably increased with the heat storage medium (i.e., water) filling in the annular cavity of the evacuated tube. The extended heating time also markedly increased by up to 170 min and was therefore of considerable practical value.
Numerical study of droplet thermocapillary migration behavior on wettability-confined tracks using a three-dimensional color-gradient lattice Boltzmann model
Authors: Fu Xiaojin , Sun Jinju , Ba Yan
Published: January 2022

Thermocapillary migration describes the phenomenon whereby liquid droplets move from warm to cold regions on a nonuniformly heated hydrophilic surface. Surface modifications can be applied to manipulate this migration process. In the present study, a three-dimensional color-gradient lattice Boltzmann model is used to investigate the droplet migration behavior on a series of wettability-confined tracks subject to a uniform temperature gradient. The model is validated by simulating the thermocapillary-driven flow with two superimposed planar fluids in a heated microchannel and the capillary penetration of a wetting fluid in a capillary tube. An in-depth study of the wettability-confined tracks confirms the capacity to manipulate the droplet migration process, that is, the wettability-confined tracks can accelerate thermocapillary migration compared with a smooth surface. The effects of changes in the viscosity ratio and interfacial tension are investigated, and it is found that a lower viscosity ratio and larger interfacial tension cause the droplet to migrate faster. Moreover, a systematic study of the track vertex angle is conducted, and the mechanism through which this parameter influences the droplet migration is analyzed. Then the effect of the track wettability on droplet migration is explored and analyzed. Finally, a serial wettability-confined track is designed to realize long-distance droplet migration, and the narrow side width of the connection region is found to play a key role in determining whether the droplets can migrate over long distances. The results provide some guidance for designing tracks that enable precise droplet migration control.
Enhanced energy harvesting performance of PIN-PMN-PT single crystal unimorph using alternating current poling
Authors: Ma Ming , Xia Song , Gao Xiangyu , Song Kexin , Guo Haisheng , Li Fei , Xu Zhuo , Li Zhenrong
Published: January 2022

In this work, the piezoelectric unimorph of a Pb(In1/2Nb1/2)O3 -Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT) single crystal by alternating current poling (ACP) was studied for vibration energy harvesting. The figure of merit of d31×g31 of the 0.25PIN-0.43PMN-0.32PT single crystal was enhanced to be 29.3 × 10−12 m2/N by ACP, which is 1.9 times and 8.9 times as much as that of the 0.25PIN-0.43PMN-0.32PT single crystal and the commercial PZT5H ceramic by direct current poling (DCP), respectively. The piezoelectric unimorph of the 0.25PIN-0.43PMN-0.32PT single crystal by ACP produced the open circuit voltage of 67 Vp and the maximum power of 0.74 mW under on-resonance condition, which were 1.5 times and 1.8 times as much as the 0.25PIN-0.43PMN-0.32PT single crystal unimorph by DCP. Moreover, these were almost 2.4 times more voltage and 5.7 times more power than the PZT5H ceramic unimorph. Even under the off resonance condition, the piezoelectric unimorph of the 0.25PIN-0.43PMN-0.32PT single crystal by DCP and ACP produced 4.4 times and 8.0 times maximum output power as much as the PZT5H ceramic unimorph. ACP is a potential way to further enhance the output voltage and power of the 0.25PIN-0.43PMN-0.32PT single crystal unimorph for energy harvesting.
TOF-SIMS analysis of decoherence sources in superconducting qubits
Authors: Murthy A. A. , Lee J. , Kopas C. , Reagor M. J. , McFadden A. P. , Pappas D. P. , Checchin M. , Grassellino A. , Romanenko A.
Published: January 2022

Superconducting qubits have emerged as a potentially foundational platform technology for addressing complex computational problems deemed intractable with classical computing. Despite recent advances enabling multiqubit designs that exhibit coherence lifetimes on the order of hundreds of μs, material quality and interfacial structures continue to curb device performance. Two-level system defects in the thin superconducting film and adjacent dielectric regions introduce stochastic noise and dissipate electromagnetic energy at the cryogenic operating temperatures. In this study, we utilize time-of-flight secondary ion mass spectrometry to understand the role specific fabrication procedures play in introducing such dissipation mechanisms in these complex systems. We interrogated Nb thin films and transmon qubit structures fabricated through slight modifications in the processing and vacuum conditions. We find that when the Nb film is sputtered onto the Si substrate, oxide and silicide regions are generated at various interfaces. We also observe that impurity species, such as niobium hydrides and carbides, are incorporated within the niobium layer during the subsequent lithographic patterning steps. The formation of these resistive compounds likely impacts the superconducting properties of the Nb thin film. Additionally, we observe the presence of halogen species distributed throughout the patterned thin films. We conclude by hypothesizing the source of such impurities in these structures in an effort to intelligently fabricate superconducting qubits and extend coherence times moving forward.
Wind speed prediction based on CEEMD-SE and multiple echo state network with Gauss–Markov fusion
Authors: Lian Lian
Published: January 2022

The purpose of this study is to improve the prediction accuracy of wind speed. The wind speed has the characteristics of unstable, non-stationary, and non-linear, so it is difficult to predict the wind speed. This study proposes a prediction model based on the complementary ensemble empirical mode decomposition-sample entropy and multiple echo state network (ESN) with Gauss–Markov fusion for wind speed. The proposed prediction model consists of the following steps: (a) using the complementary ensemble empirical mode decomposition algorithm, it decomposes the initial wind speed time series and obtains some components with different scales, and (b) using the sample entropy algorithm, it determines the complexity of each component. The components whose entropy is larger than the original wind speed remain unchanged, while the components whose entropy is smaller than the original wind speed are merged into one. The reconstructed component greatly reduces the number of prediction models. (c) After reconstruction, the ESN has good regression prediction ability, so it is chosen as the prediction model of each component. The gray wolf optimization algorithm is introduced to optimize the parameters of the ESN. (d) The Gauss–Markov algorithm is adopted to fuse the predicted values of multiple ESN models. The variance of the predicted value obtained using the Gauss–Markov fusion is less than that of the single ESN model, which significantly increases the prediction accuracy. In order to verify the prediction performance of the proposed model, the actual ultra-short-term and short-term wind speed sample data are compared. At the same time, seven prediction models are chosen as the comparison model. Finally, through the comparison of the prediction error and its histogram distribution, eight performance indicators, Pearson’s correlation coefficient, and Diebold–Mariano test, all the results show that the proposed prediction model has high prediction accuracy.
Mechanical disruption of E-cadherin complexes with epidermal growth factor receptor actuates growth factor–dependent signaling
Authors: Sullivan Brendan , Light Taylor , Vu Vinh , Kapustka Adrian , Hristova Kalina , Leckband Deborah
Published: January 2022

Significance

Force transduction at interepithelial junctions involves E-cadherin–mediated activation of epidermal growth factor receptor (EGFR) signaling, which modulates local cytoskeletal remodeling and cell proliferation. Findings show that E-cadherin and EGFR form a heteroreceptor complex at the membrane. Increased tension on E-cadherin bonds disrupts the complex in the absence of epidermal growth factor (EGF), but the mechanical activation of EGFR signaling requires soluble EGF. Fully quantified spectral imaging fluorescence resonance energy transfer measurements further revealed that E-cadherin and EGFR form a heterotrimeric complex at the plasma membrane, comprising two E-cadherins bound to an EGFR monomer. These results suggest that tugging forces on E-cadherin adhesions activate force transduction cascades, by releasing EGFR monomers from the complex, to enable EGFR to homodimerize, bind EGF, and signal.
Identification of genetic risk loci and prioritization of genes and pathways for myasthenia gravis: a genome-wide association study
Authors: Chia Ruth , Saez-Atienzar Sara , Murphy Natalie , Chiò Adriano , Blauwendraat Cornelis ,   International Myasthenia Gravis Genomics Consortium, Roda Ricardo H. , Tienari Pentti J. , Kaminski Henry J. , Ricciardi Roberta , Guida Melania , De Rosa Anna , Petrucci Loredana , Evoli Amelia , Provenzano Carlo , Drachman Daniel B. , Traynor Bryan J. , Abramzon Yevgeniya , Barohn Richard J. , Benatar Michael , Blackmore Derrick , Chaudhry Vinay , Chiò Adriano , Chopra Manisha , Corse Andrea , Rosa Anna De , Dimachkie Mazen M. , Evoli Amelia , Florence Julaine , Freimer Miriam , Guida Melania , Howard James F. , Jiwa Theresa , Kaminski Henry J. , Kissel John T. , Koopman Wilma J. , Lipscomb Bernadette , Maestri Michelangelo , Marino Mariapaola , Massey Janice M. , McVey April , Mezei Michelle M. , Muppidi Srikanth , Nicolle Michael W. , Oger Joel , Pascuzzi Robert M. , Pasnoor Mamatha , Pestronk Alan , Petrucci Loredana , Pliner Hannah A. , Provenzano Carlo , Renton Alan E. , Ricciardi Roberta , Richman David P. , Rowin Julie , Sanders Donald B. , Sabatelli Mario , Siddiqi Zaeem , Soloway Aimee , Todi Laura , Wolfe Gil , Wulf Charlie , Drachman Daniel B. , Traynor Bryan J.
Published: January 2022

Significance

Our study, involving 1,873 patients and 36,370 healthy individuals, is an extensive genome-wide study of myasthenia gravis. Our genome-wide association and transcriptome-wide association analyses identified two signals, namely
CHRNA1
and
CHRNB1
, encoding acetylcholine receptor subunits, which were replicated in an independent cohort obtained from the UK Biobank. Identifying these genes confirms the potential utility of using genetics to identify proteins that are the antigenic targets of autoantibodies. We confirmed that the genetic abnormalities underlying early-onset and late-onset myasthenia gravis are different. Our data offer a broader insight into the genetic architecture underlying the pathophysiology of myasthenia gravis.
Characterizing cell interactions at scale with made-to-order droplet ensembles (MODEs)
Authors: Madrigal Justin L. , Schoepp Nathan G. , Xu Linfeng , Powell Codian S. , Delley Cyrille L. , Siltanen Christian A. , Danao Jay , Srinivasan Maithreyan , Cole Russell H. , Abate Adam R.
Published: January 2022

Significance

The study of specific cell–cell interactions at scale would be a significant advancement in single-cell biology with clear utility in immuno-oncology. Our development of Droplet Assembly provides a tool for such studies by extending the benefits of single-cell droplet microfluidics to high-order cell analyses. This technology allows for the construction, sorting, and downstream processing of cell–cell interactions and is compatible with single-cell genomic readouts.
Ultrafast atomic view of laser-induced melting and breathing motion of metallic liquid clusters with MeV ultrafast electron diffraction
Authors: Wu Jun , Tang Minxue , Zhao Lingrong , Zhu Pengfei , Jiang Tao , Zou Xiao , Hong Liang , Luo Sheng-Nian , Xiang Dao , Zhang Jie
Published: January 2022

Significance

Intense lasers can be used to drive materials into transient states far from equilibrium. Investigations of such states and processes at the atomic scale are of fundamental significance in understanding a material’s behavior under extreme conditions. Herein, an ultrafast electron diffraction technique is used to track the atomic pathway of the entire melting process of aluminum and reveal a coherent breathing motion of polyhedral clusters in transient liquid aluminum at high temperature and high pressure. The negative expansion behavior of interatomic distances in a superheated liquid state upon heating is observed. These findings provide insight into ultrafast structural transformations and transient atomic dynamics under extreme conditions.
Translational control of
E2f1
regulates the
Drosophila
cell cycle
Authors: Øvrebø Jan Inge , Bradley-Gill Mary-Rose , Zielke Norman , Kim Minhee , Marchetti Marco , Bohlen Jonathan , Lewis Megan , van Straaten Monique , Moon Nam-Sung , Edgar Bruce A.
Published: January 2022

Significance

Here, we explore a mechanism wherein the growth signaling-dependent translation of mRNA encoding a cell cycle regulatory factor limits rates of cell proliferation. An essential cell cycle transcription factor, E2F1, was found to be post-transcriptionally regulated by TOR and EGFR signaling, and thus served as a candidate growth sensor for this study. Using expression of green fluorescent protein (GFP)-E2F1 transgenes with alterations within the
E2f1
5′ untranslated region (UTR), we altered the translation of GFP-E2F1 and changed cell proliferation rates accordingly. Further, we found that 5′UTR upstream open reading frames are TOR-sensitive regulatory components of
E2f1
translation. Our observations indicate that growth signaling dependent protein translation is an important regulator of cell proliferation.
Convergent evolution of a blood-red nectar pigment in vertebrate-pollinated flowers
Authors: Roy Rahul , Moreno Nickolas , Brockman Stephen A. , Kostanecki Adam , Zambre Amod , Holl Catherine , Solhaug Erik M. , Minami Anzu , Snell-Rood Emilie C. , Hampton Marshall , Bee Mark A. , Chiari Ylenia , Hegeman Adrian D. , Carter Clay J.
Published: January 2022

Significance

Beyond sugars, many types of nectar solutes play important ecological roles; however, the molecular basis for the diversity of nectar composition across species is less explored. One rare trait among flowering plants is the production of colored nectar, which may function to attract and guide prospective pollinators. Our findings indicate convergent evolution of a red-colored nectar has occurred across two distantly related plant species. Behavioral data show that the red pigment attracts diurnal geckos, the likely pollinator of one of these plants. These findings join a growing list of examples of distinct biochemical and molecular mechanisms underlying evolutionary convergence and provide a fascinating system for testing how interactions across species drive the evolution of novel pigments in an understudied context.
MDGA1 negatively regulates amyloid precursor protein–mediated synapse inhibition in the hippocampus
Authors: Kim Jinhu , Kim Seungjoon , Kim Hyeonho , Hwang In-Wook , Bae Sungwon , Karki Sudeep , Kim Dongwook , Ogelman Roberto , Bang Geul , Kim Jin Young , Kajander Tommi , Um Ji Won , Oh Won Chan , Ko Jaewon
Published: January 2022

Balanced synaptic inhibition, controlled by multiple synaptic adhesion proteins, is critical for proper brain function. MDGA1 (meprin, A-5 protein, and receptor protein-tyrosine phosphatase mu [MAM] domain-containing glycosylphosphatidylinositol anchor protein 1) suppresses synaptic inhibition in mammalian neurons, yet the molecular mechanisms underlying MDGA1-mediated negative regulation of GABAergic synapses remain unresolved. Here, we show that the MDGA1 MAM domain directly interacts with the extension domain of amyloid precursor protein (APP). Strikingly, MDGA1-mediated synaptic disinhibition requires the MDGA1 MAM domain and is prominent at distal dendrites of hippocampal CA1 pyramidal neurons. Down-regulation of APP in presynaptic GABAergic interneurons specifically suppressed GABAergic, but not glutamatergic, synaptic transmission strength and inputs onto both the somatic and dendritic compartments of hippocampal CA1 pyramidal neurons. Moreover, APP deletion manifested differential effects in somatostatin- and parvalbumin-positive interneurons in the hippocampal CA1, resulting in distinct alterations in inhibitory synapse numbers, transmission, and excitability. The infusion of MDGA1 MAM protein mimicked postsynaptic MDGA1 gain-of-function phenotypes that involve the presence of presynaptic APP. The overexpression of MDGA1 wild type or MAM, but not MAM-deleted MDGA1, in the hippocampal CA1 impaired novel object-recognition memory in mice. Thus, our results establish unique roles of APP–MDGA1 complexes in hippocampal neural circuits, providing unprecedented insight into
trans
-synaptic mechanisms underlying differential tuning of neuronal compartment-specific synaptic inhibition.
Conformation-driven strategy for resilient and functional protein materials
Authors: Mu Xuan , Yuen John Se Kit , Choi Jaewon , Zhang Yixin , Cebe Peggy , Jiang Xiaocheng , Zhang Yu Shrike , Kaplan David L.
Published: January 2022

Significance

We provide insights into the sequence–conformation–property relationship that is central to the mechanical properties of protein elastomers. We find that a high content of glycine residue alone, not including proline, is sufficient for achieving near-perfect resilience. The content of proline residue may be associated with the metastability of random coils. Also, Raman spectroscopy, as a potent tool for investigating the conformation–property relationship, gives rise to a direct correlation between semiquantitative Raman features and the magnitude of elastic resilience. Moreover, metastable conformation or conformational polymorphism is useful to develop continuously and mechanically graded protein materials that may exhibit unique structural merits. This work underlies the exploitation of natural and de novo–designed sequences for protein elastomers and materials.
DNA-induced spatial entrapment of general transcription machinery can stabilize gene expression in a nondividing cell
Authors: Javed Khayam , Jullien Jerome , Agarwal Gaurav , Lawrence Nicola , Butler Richard , Ioannou Pantelis Savvas , Nazir Farhat , Gurdon J. B.
Published: January 2022

Significance

How differentiated cells such as muscle or nerve maintain their gene expression for prolonged times is currently elusive. Here, using Xenopus oocyte, we have shown that the stability of gene expression in nondividing cells may arise due to the local entrapment of transcriptional machinery to specific gene transcription start sites. We found that within the same nucleus active versus inactive versions of the same gene are spatially segregated through liquid–liquid phase separation. We further observe that silent genes are associated with RNA-Pol-II phosphorylated on Ser5 but fails to attract RNA-Pol-II elongation factors. We propose that liquid–liquid phase separation mediated entrapment of limiting transcriptional machinery factors maintain stable expression of some genes in nondividing cells.
Sex-specific splicing of Z- and W-bornenr5a1alleles suggests sex determination is controlled by chromosome conformation
Authors: Zhang Xiuwen , Wagner Susan , Holleley Clare E. , Deakin Janine E. , Matsubara Kazumi , Deveson Ira W. , O’Meally Denis , Patel Hardip R. , Ezaz Tariq , Li Zhao , Wang Chexu , Edwards Melanie , Graves Jennifer A. Marshall , Georges Arthur
Published: January 2022

Significance

Reptiles have an extraordinary variety of mechanisms to determine sex. The best candidate sex-determining gene in our model reptile (the Australian central bearded dragon) is the key vertebrate sex genenr5a1(coding for the steroidogenic factor 1). There are no sex-specific sequence differences betweennr5a1alleles on the sex chromosomes, but the Z- and W-borne alleles are transcribed into remarkably different alternative transcripts. We propose that altered configuration of the repeat-laden W chromosome affects the conformation of the primary transcript to generate more diverse and potentially inhibitory W-borne isoforms that suppress testis determination. This is a mechanism for vertebrate sex determination, in which epigenetic control regulates the action of a gene present on both sex chromosomes.
Illusory faces are more likely to be perceived as male than female
Authors: Wardle Susan G. , Paranjape Sanika , Taubert Jessica , Baker Chris I.
Published: January 2022

Significance

Face pareidolia is the phenomenon of perceiving illusory faces in inanimate objects. Here we show that illusory faces engage social perception beyond the detection of a face: they have a perceived age, gender, and emotional expression. Additionally, we report a striking bias in gender perception, with many more illusory faces perceived as male than female. As illusory faces do not have a biological sex, this bias is significant in revealing an asymmetry in our face evaluation system given minimal information. Our result demonstrates that the visual features that are sufficient for face detection are not generally sufficient for the perception of female. Instead, the perception of a nonhuman face as female requires additional features beyond that required for face detection.
Dual-channel scattering problem in the cavity-like potential
Authors: Yamakoshi Tomotake , Watanabe Shinichi
Published: January 2022

We discuss one-dimensional dual-channel barrier scattering with a cavity-like structure in terms of a time-independent problem. Our model assumes that the channels interact with each other only through the cavity-like structure. The model is capable of describing the essential physics of resonant scattering such that electromagnetically induced transparency and Fano-resonance type lineshapes appear in the spectrum. In this paper, we give a complete analytical solution of the spectrum. In addition, using approximate solutions, we show how the spectrum is explained by the simplified resonant condition and appearance of zero points. The results can be checked by simple numerical calculations, making this problem suitable as a teaching aid for beginners.
Design and optimization of high-efficiency meta-devices based on the equivalent circuit model and theory of electromagnetic power energy storage
Authors: Xu Peng , Wang Gui Chen , Cai Xiao , Shen Hai Yang , Jiang Wei Xiang
Published: January 2022

Meta-devices with high operation efficiency to control electromagnetic waves are of great interest in a variety of applications. In this paper, we propose a general design method to achieve maximum operating efficiency for different-function meta-devices. The method is based on the equivalent circuit model and the theory of electromagnetic energy storage. To demonstrate its validity, three different kinds of functional meta-devices, including a beam deflection meta-array, circular polarization microwave absorber and linear-to-circular polarization converter, are presented using the proposed method. The method can be used for arbitrarily-structured meta-devices, three-dimensional (3D) all-metal structures or planar dielectric-metal-mixed structures. Additionally, such a method may be applied to design meta-devices for any polarized waves and can be expanded to other operating frequency bands.
Perpendicular magnetization anisotropy induced dynamical coherence reduction in stripe domain film
Authors: Li Qiuyue , Song Yawen , Wang Fangzhou , Liu Meihong , Ma Xiaoqi , Guo Xinfang , Chen Xiaowen , Yu Jing , Du Shuai , Li Hao , Xu Jie , Li Shandong , Cao Derang
Published: January 2022

We investigated the magnetization dynamics of the 350 nm permalloy film with in plane domain (IPD), stripe domain (SD), and labyrinth domain (LD) patterns. Experimental and micromagnetic simulation results showed that the change in magnetic domain structure from IPD to LD was due to the increasing perpendicular magnetic anisotropy (PMA) of the film. The magnetization dynamics indicated that the resonant modes of the film strongly depended on the magnetic domain structure. IPD films presented a uniform precession mode. The film with well-regular SD exhibited clear acoustic and optical resonance modes, and the formation of LD suppressed both resonance modes. Finally, the dynamics of magnetization dependent on the domain structure in these films were discussed by using the phenomenological resonance models.
Band theoretical approaches to topological physics in strongly-correlated f-electron Kondo systems
Authors: Kang Chang-Jong , Kim Kyoo , Min B I
Published: January 2022

First-principles band structure theory on the basis of the density functional theory (DFT) plays an essential role in the investigation of topological properties of weakly-correlated systems. DFT band structures show clear bulk band crossings for Weyl and Dirac semimetals, and surface band crossings for topological insulators and topological-crystalline insulators. In contrast, for strongly-correlated f-electron systems, their topological properties are relatively less explored because the simple DFT does not work properly in describing the electronic structures of strongly-correlated f electrons. In this perspective, we examine the band theoretical approaches to topological properties of strongly-correlated f-electron Kondo systems. We recapitulate current status of understanding of electronic structures and topological properties of strongly-correlated 4f-electron systems, such as Ce, SmB6, and g-SmS, and also a 5f-electron system PuB4, the electronic structures of which were investigated by the DFT combined with the dynamical mean-field theory (DFT + DMFT). Finally, we provide future directions and perspectives of improving theoretical band approaches to search for new topological f-electron systems, as an outlook.
Route to a direct-gap silicon allotrope Si32
Authors: Tao Shuo , Zhu Li
Published: January 2022

Using swarm-intelligence-based structure prediction methods, we predict a novel direct bandgap silicon allotrope with open channels at ambient conditions. This silicon phase, termed Si32, can be produced by removing Sr atoms from a new Cmcm-SrSi8 clathrate-like compound, which is calculated to be thermodynamically stable under epitaxial strain at high pressures. Si32 is predicted to have a direct bandgap of ∼1.15 eV and exceptional optical properties. The prediction of novel silicon clathrate-like structure paves the way for the exploration of novel silicon phases with extensive application possibilities.
Impact of the incorrect use of lead drapes on staff and patient doses in interventional radiology
Authors: Lima Thiago V M , Del Castillo Tomas Reyes , Heinrich Mirjam , Zihlmann Stephanie , Benitez Ruben Lopez , Roos Justus E
Published: January 2022

To evaluate the usefulness of commercially available scatter reduction drapes in mitigating staff exposure in interventional radiology and the potential harmful effects of drape malpositioning in terms of exposure levels to both patients and staff. An anthropomorphic phantom was irradiated on an angiography device under three scenarios: no drape and correct and incorrect drape positioning. Different levels of incorrect drape positioning relative to the field-of-view (FOV) were evaluated: slight, mild and severe. Real-time dosimeter systems (positioned on the operator’s eye, chest and thyroid) were used to evaluate accumulative doses and dose rates. Different obstruction levels were evaluated and compared to the observer’s perception. Additionally, patient exposure was evaluated for all scenarios using a dose area product (DAP). Up to a mild obstruction, by using the drape a dose reduction of up to 86% was obtained while a severe obstruction produced a 1000% increase in exposure, respectively for all dosimeter positions compared to the use of no drape. A similar order of magnitude was observed for patient exposure. Good agreement was obtained for the observer perception of the FOV obstruction up to 25% of the FOV; for larger obstructions, an overestimate of the obstruction was observed. Patient lead drapes can reduce staff doses in interventional radiology procedures even when mildly malpositioned and obscuring the FOV. Special attention to protective drape positioning is necessary, since the severe obstruction of the FOV results in a large increase in both operator and patient exposure.
Broccoli-liked silver phosphate nanoparticles supported on green nanofiber membrane for visible-light driven photodegradation towards water pollutants
Authors: Jin Xu , Lou Yaoyuan , Zhang Xiuqin , Wang Bin , Zhu Yanlong , Gu Xiaoxia , Ding Shanshan , Ma Jiayu
Published: January 2022

In view of the practical application, it is imperative to develop efficient, exercisable, and visible light driven water pollution treatment materials. Herein, a high-efficiency green photocatalytic membrane for water pollution treatment is proposed and fabricated conveniently. Firstly, silver phosphate (Ag3PO4) nanoparticles with controlled morphology were prepared by simple liquid-phase precipitation method, and then a hierarchical structured Ag3PO4@polylactic acid (PLA) composite nanofiber membrane was prepared by electrospinning. Using electrospun PLA nanofiber membrane as a carrier of photocatalysts can significantly improve the dispersion of Ag3PO4 nanoparticles, and increase the contact probability with pollutants and photocatalytic activity. The prepared PLA@Ag3PO4 composite membrane was used to degrade methylene blue (MB) and tetracycline hydrochloride (TC) under visible light irradiation. The results showed that the removal ratio of pollutants on Ag3PO4@PLA composite nanofiber membrane was 94.0% for MB and 82.0% for TC, demonstrating an outstanding photocatalytic activity of composite membrane. Moreover, the PLA nanofiber membrane is a self-supported and biodegradable matrix. After five cycles, it can still achieve 88.0% of the initial photocatalytic degradation rate towards MB, showing excellent recyclability. Thus, this composite nanofiber membrane is a high-efficiency and environmental-friendly visible light driven water pollution treatment material that could be used in real applications.
Unstable spectra of plane Poiseuille flow with a uniform magnetic field
Authors: Wei Lai , Liu Yunxia , Yu Fang , Ren Haijun , Wang Zheng-Xiong , Liu Yue , Peng Hang
Published: January 2022

The unstable spectra of plane Poiseuille flow (PF) in the presence of a longitudinal magnetic field are numerically investigated using an eigenvalue solver of incompressible magnetohydrodynamic equations. It is found that the strength of the magnetic field and the dissipative effect of the magnetic perturbation have played different roles in different parameter regions. The magnetic field has a strong suppression effect on the classical plane PF instability with a large Reynolds number

in the region with the magnetic Prandtl number

or the magnetic Reynolds number

. Here, the Reynolds number and the magnetic Reynolds number are defined as

and

, where a, V
0, ν and η are the typical length, velocity, viscosity and resistivity, respectively. The magnetic Prandtl number is defined as

, which is proportional to the ratio of the viscosity and the resistivity of the fluid medium. As the strength of the magnetic field increases, the PF instability can be completely stabilized in the limit of

or/and

. It is interestingly found that a new instability branch is excited in the small magnetic Prandtl number (

) or moderate magnetic Reynolds number (

) and large Reynolds number (

) regions. This new type of instability is verified to be driven by the magnetic Reynolds stress and modulated by the dissipative effect of the magnetic perturbation. The wavelength of the original PF instability gradually shifts to the long wavelength region, but the wavelength of the new branch is almost unchanged, as

increases with fixed

. However, the wavelength of the original instability branch is almost unchanged, but the wavelength of the new instability branch shifts to the long wavelength region, as

increases with fixed

.