bluuebunny/crossref_metadata_2025 huggingface dataset:
Plasma-assisted flame stabilization by AC dielectric barrier discharge in burst mode
Authors: Zhou Siyin , Tong Yiheng , Zheng Zhi , Nie Wansheng , Yang Yunfan , Liu Xiang
Published: November 2021

Compared to the continuous mode of a high-frequency alternating current (HFAC) source, the burst mode is believed to be capable of controlling flow and combustion while saving discharge energy. Thus, the effect of burst mode on plasma-assisted flame stabilization, which is driven by an HFAC source, is investigated based on a plasma manipulation diffusion flame experiment system. A specially designed injector with a coaxial dielectric barrier discharge configuration is used to generate a methane-air diffusion flame and air plasma. The influence of the actuating parameters of the burst mode on plasma flame stabilization and the discharge power consumption are studied. The results show that the plasma injector has the typical volt–ampere characteristics of dielectric barrier discharge. The discharge clearly exhibits regular unsteady operation characteristics when the source is in burst mode. Two flame stability thresholds are found with increasing discharge voltage. According to the first and second flame stability threshold values and the flame pattern, raising the control frequency and the duty cycle is favorable for flame stabilization. However, for a fixed duty cycle of 50%, because the time scale of the actuator-off duration is longer than that of combustion, when the control frequency is too low, the flame cannot be stabilized even though the applied voltage is very high. For a fixed control frequency of 100 Hz, the flame is also difficult to stabilize when the duty cycle is too small. Mainly due to the unsteady gasdynamic effects of plasma in the burst mode, this approach can achieve the same flame stabilization effect as that of the continuous mode while reducing the energy consumption. The cost-effectiveness ratios of the two optimum actuation schemes are only 6.4% and 10.1%. In addition, the burst mode is better than the continuous mode in avoiding undesirable arc discharge. To better stabilize the flame while maintaining a relatively low cost-effectiveness ratio, actuator setting schemes with high frequency and a small duty cycle should be selected.
Propagation of gaseous detonation in spatially inhomogeneous mixtures
Authors: Wang Yuan , Chen Zheng , Chen Haitao
Published: November 2021

In advanced detonation engines for propulsion and in strong accidental explosions with detonation development, spatially inhomogeneous mixtures may occur which can greatly affect the detonation propagation. In this study, detonation propagation in spatially inhomogeneous mixtures is investigated via numerical simulation considering detailed chemistry. The two-dimensional (2D) periodic sinusoidal distribution of reactant concentration is introduced in the inhomogeneous region. The emphasis is on assessing the effects of such spatially inhomogeneous mixture on local explosion and subsequent detonation development. It is found that successful detonation propagation always occurs in the spatially inhomogeneous mixtures with 2D periodic sinusoidal distribution of reactant concentration. This is interpreted through the formation and collision of curved shocks, local autoignition, and explosions happened in the first sinusoidal period. Moreover, the effects of wavelength and amplitude of sinusoidal distribution on the cellular structure and detonation speed are assessed. It is found that the detonation speed decreases as both the wavelength and amplitude increase. Unlike the detonation speed, three modes of the cellular structure, respectively, from the original cellular structure and local explosion are identified depending on the values of wavelength and amplitude. Furthermore, the position of the first local explosion is always found to be located in the high reactivity zones of the second half of first sinusoidal period. Furthermore, comparison between simulation results for one-dimensional (1D) and 2D periodic sinusoidal distribution of reactant concentration indicates that the formation of curved shocks and their collision caused by 2D sinusoidal distribution are crucial for successful detonation propagation in the inhomogeneous region. The present study helps to understand the detonation propagation in inhomogeneous mixtures.
Inspection of contamination in nitrogen plasmas by monitoring the temporal evolution of the UV bands of NO-γ and of the fourth positive system of N2
Authors: Carrivain O. , Hugon R. , Marcos G. , Noël C. , Skiba O. , Czerwiec T.
Published: November 2021

In this study, contamination by oxygen species in nitrogen plasmas produced by the active screen system used for plasma nitriding has been investigated by optical emission spectroscopy in the spectral range of 200–900 nm. Temporal evolution of emission intensity of different species (N2, N2+, NO, OH, H, NH, and Fe) was monitored, as well as electrical characteristics (current and voltage) of the discharge produced by a pulsed unipolar power supply. In nitrogen plasma, it was found that the emission of oxygen-containing species (NO and OH) decreases with time, while Fe emission intensity increases. Such behavior is observed only when the discharge is initiated immediately after venting the reactor. Starting from the hypothesis of contamination of the reactor walls by water vapor, we propose an explanation based on the synergistic effect between the temperature and the reactive nitrogen created by the plasma. Such a long decay of NO emission was not observed in N2–H2 gas mixtures. After decontamination, the fourth positive system of N2 could be observed. Such a not commonly observed system can be used as a tool to control reactor cleanliness in pure nitrogen discharge for nitriding applications.
Thickness effect on scaling law and surface properties of nano-dimensional SnTe thin films
Authors: Maity G. , Yadav R. P. , Singhal R. , Sulania I. , Mittal A. K. , Chaudhary Dhirendra. K. , Kanjilal D. , Patel Shiv. P.
Published: November 2021

SnTe is an important material because of its applications in mid-infrared photo-detectors. In the present work, the effects of film thickness on scaling law and surface properties (i.e., morphologies and optical properties) of SnTe thin films have been investigated. SnTe thin films of different thicknesses are prepared by means of e-beam evaporation technique. The surface morphology of each film is analyzed by atomic force microscopy (AFM) as well as a scanning electron microscope. The crystallinity of the films is found to increase with increasing film thickness, as confirmed by x-ray diffraction and Raman measurements. Fractal analysis is performed on AFM images to investigate the irregularity of surfaces. It is found that the surface of the thicker sample is rougher than the thinner sample. The autocorrelation function is applied to investigate the self-affine fractal nature of surfaces. The average roughness, interface width, lateral correlation length, local surface slope, and fractal dimension increased with film thickness. The values of roughness exponent, growth exponent, dynamic exponent, and steepening exponent are calculated and found to be α=0.76-0.96, β=0.75, z=1.92, and λ=0.35-0.25, respectively. The scaling exponents together with the other parameters such as the local surface slope indicate that the growth is quasi-3D island/mound type with rapid surface roughening behavior and obeys anomalous scaling. The multiple scattering cross sections of light together with Fourier transform infrared spectroscopy data analyses suggest that the higher crystalline film with a smaller number of defects is infrared-sensitive and may be more suitable for advanced mid-infrared detector applications.
An experimental study on the transient runback characteristics of wind-driven film/rivulet flows
Authors: Zhang Kai , Hu Hui
Published: November 2021

A comprehensive experimental campaign was conducted to characterize the dynamic runback process of wind-driven water film/rivulet flows for a better understanding of the transient surface water transport process pertinent to aircraft icing phenomena. The experimental study was conducted by using an open-circuit wind tunnel to generate laminar boundary layer airflows with different freestream wind speeds to drive thin water film/rivulet flows over a flat test plate. A digital image projection (DIP) technique was used to achieve non-intrusive, temporally and spatially resolved measurements of the film thickness distributions to characterize the dynamic runback process of the wind-driven film/rivulet flow under different test conditions. Important characteristics of the wind-driven water runback process—such as the generation of well-organized two-dimensional (i.e., 2D) and more complicated three-dimensional (i.e., 3D) surface waves at air/water interfaces, stumbling runback motion of the film/rivulet heads in “acceleration-and-deceleration” cycles, breaking up the front contact lines to form multiple rivulet flows, meandering and merging of the rivulet flows—were revealed clearly and quantitatively based on the DIP measurements. A comprehensive force balance analysis was also performed to examine the variations of the relevant forces (i.e., the excess pressure forces built inside the film/rivulet flows, aerodynamic drag forces acting on the rivulet heads, and the restraining forces due to the surface tension along the liquid contact lines) and evaluate their importance in the breakoff of the stagnated film/rivulet heads to re-start the runback process of the wind-driven film/rivulet flows.
Science and Society
Authors: Lock Frank
Published: November 2021

“Science and Society” is a look at the relationships between physics and the culture in which we live. “An Answer for Joanna” consists of recommendations from Cliff regarding information high school students should have about choosing a postsecondary institution to attend. “Images and Views” is an analysis of the challenges scientists face when communicating with citizens. What students learn on field trips is examined in “Extracurricular Fun and Games.” Making the experience of a physics course enticing to students is assessed in “Physics Can Be Phun and Also Phony.” “Models and Reality” deals with the nature of science.
Dissipative aspects of extreme nonlinear optics
Authors: Rosanov N.N. , Aleksandrov I.A. , Arkhipov M.V. , Arkhipov R.M. , Babushkin I. , Veretenov N.A. , Dadeko A.V. , Tumakov D.A. , Fedorov S.V.
Published: November 2021

Studies of extreme nonlinear optical effects, in which dissipative factors such as absorption and amplification of light in a medium play a fundamental role, are reviewed. The generation of pulses with extremely short duration down to unipolar ones is analysed by tracking the development of ideas related to the self-induced transparency phenomenon, whose practical application becomes real for extremely short pulses in lasers and laser media. Extreme radiation structuring is achieved in dissipative (laser) solitons characterised by a complex topology of phase and polarisation singularities, which is of interest for coding information.
Time integration and differentiation of unipolar pulses of unusual shape
Authors: Pakhomov A.V. , Arkhipov R.M. , Arkhipov M.V. , Rosanov N.N.
Published: November 2021

Based on the previously developed theory of transformation (time integration and differentiation) of ultrashort pulses in thin metal films, we study the possibility of time differentiation and integration of unipolar pulses. Unipolar pulses of unusual shape–rectangular and triangular–are considered, and their mutual transformation upon propagation through thin films with certain parameters is demonstrated. The conservation of the electrical area in such problems is shown.
Use of dielectric nanoparticles doped with Yb3+ ions to enhance the thermal effect in a biological tissue exposed to near-IR laser radiation (in vivo experiments)
Authors: Ryabochkina P.A. , Khrushchalina S.A. , Belyaev A.N. , Bushukina O.S. , Yurlov I.A. , Kostin S.V.
Published: November 2021

The conditions for the appearance of broadband radiation from particles of zirconium dioxide stabilised by ytterbium oxide upon excitation by intense laser radiation with a wavelength of 980 nm are investigated. It is shown that this radiation is observed at a lower excitation power density and lower ytterbium content than in particles of orthophosphates and their hydrates. As a result of in vivo experiments, the possibility of using ytterbium-containing particles to enhance the thermal effect from exposure to laser radiation with a wavelength of 980 nm on the skin of a rat is demonstrated.
Modulation instability of two TE modes in a thin left-handed film on a nonlinear right-handed substrate
Authors: Buller A.S. , Zelenetskaya Yu.V. , Litvinov R.V. , Melikhova N.R.
Published: November 2021

The intramode wave beams in a thin left-handed film on a Kerr substrate are considered at a frequency near zero mode group velocity. Four coupled (1 + 1)-dimensional nonlinear Schrödinger equations, describing the interaction of forward and backward propagating beams with positive and negative group velocities, are derived. It is shown that self- and cross-phase modulation for four simultaneously propagating modes is possible only at strictly matched perturbations of their propagation constants, which is due to the contribution of spatial parametric mixing. The modulation instability of only two waveguide modes is analysed for different versions of their propagation. The specific features of modulation instability, related to the propagation of modes with negative group velocities, are investigated.
Efficiency improvement of the femtosecond laser source of superponderomotive electrons and X-ray radiation due to the use of near-critical density targets
Authors: Andreev N.E. , Popov V.S. , Rosmej O.N. , Kuzmin A.A. , Shaykin A.A. , Khazanov E.A. , Kotov A.V. , Borisenko N.G. , Starodubtsev M.V. , Soloviev A.A.
Published: November 2021

We consider the possibility of improving the superhigh-power laser pulse to superponderomotive electrons energy conversion efficiency by using porous targets of near-critical density. We report the results of numerical simulations based on the typical parameters of laser pulses of the PEARL laser facility built on the principles of parametric chirped pulse amplification (OPCPA). An original scheme for producing a controllable prepulse based on the use of a pump laser switched to a two-pulse regime is discussed. The prepulse is required to homogenise the submicron inhomogeneities of a porous target. Simulations show a significant increase in the laser-to-electron energy conversion efficiency in comparison with solid-state and gas targets. This interaction regime can be used to improve the efficiency of a broad class of laser-driven secondary radiation sources, such as a betatron source, bremsstrahlung, neutron source, etc.
Reproductive coercion and abuse in Australia: what do we need to know?
Authors: Carter Allison , Bateson Deborah , Vaughan Cathy
Published: November 2021

Reproductive coercion and abuse refers to patterns of controlling and manipulative behaviours used to interfere with a person’s reproductive health and decision-making. Unintended pregnancy, forced abortion or continuation of a pregnancy, and sexually transmissible infections all may result from reproductive coercion, which is closely associated with intimate partner and sexual violence. Clinicians providing sexual and reproductive healthcare are in a key position to identify and support those affected. Yet, reproductive coercion and abuse is not currently screened for in most settings and addressing disclosures poses many challenges. This article discusses what reproductive coercion and abuse is, who it affects, how it impacts, and potential strategies to improve identification and response.
Experimental observation of the origin and structure of elastoinertial turbulence
Authors: Choueiri George H. , Lopez Jose M. , Varshney Atul , Sankar Sarath , Hof Björn
Published: November 2021

Significance

The motion of viscoelastic fluids often strikingly differs from the Newtonian standard case. Elastic fluid properties tend to give rise to instability and chaotic motion at low inertia yet suppress turbulence at high inertia. In experiments of polymer solutions, we identify the dynamical mode that dominates the onset of the recently discovered state of “elastoinertial turbulence” (EIT), and our observations allow us to discriminate between the various theoretical models attempting to explain the state’s origin. Moreover, we demonstrate that the characteristic EIT structures can be traced across more than three orders of magnitude in Reynolds number, suggesting that EIT plays as dominant a role in high-shear viscoelastic flows as ordinary turbulence does in high-inertia Newtonian flows.
Study of coefficient of discharge through orifices
Authors: Wadhwa Ajay
Published: November 2021

A physical quantity called coefficient of discharge, defined as the ratio of actual discharge to the theoretical discharge, is of keen interest in the liquid flow through an orifice. We have investigated the discharge coefficient of the liquid (water) flow through orifices of two different shapes namely the circular and the square. We use the basic arrangement in which the water contained in a long vertical pipe, after falling through a height, is allowed to flow out of an orifice located at its bottom. For our experiment, we have used an Arduino based technique to dynamically record the position of the falling water level as a function of time. We compare the values of the coefficient of discharge obtained in this work with those reported earlier using conventional methods.
Thermal and plasma enhanced atomic layer deposition of ultrathin TiO2 on silicon from amide and alkoxide precursors: growth chemistry and photoelectrochemical performance
Authors: O’Donnell S , Jose F , Shiel K , Snelgrove M , McFeely C , McGill E , O’Connor R
Published: November 2021

Due to its low cost and suitable band gap, silicon has been studied as a photoanode material for some time. However, as a result of poor stability during the oxygen evolution reaction (OER), Si still remains unsuitable for any extended use. Ultra-thin titanium dioxide (TiO2) films have been used as protective coatings and are shown to enhance Si photoanode lifetime with added solar to hydrogen performance improvements through distancing the oxidation reaction away from the Si photoanode surface and improved charge transport through the anode. This study details the nucleation, growth chemistry, and performance of TiO2 thin films prepared via thermal and plasma enhanced atomic layer deposition (ALD) using both titanium isopropoxide and tetrakis(dimethylamido)titanium as the precursor material. The effect of post ALD treatments of plasma and air annealing was also studied. Films were investigated using photoelectrochemical cell testing to evaluate photoelectrochemical performance, and in-vacuum cycle-by-cycle x-ray photoelectron spectroscopy was used as the primary characterisation technique to study nucleation mechanisms and film properties contributing to improvements in cell performance. TiO2 grown by plasma enhanced ALD results in cleaner films with reduced carbon incorporation. However, despite increased carbon incorporation, thermally grown films showed improved photocurrent as a result of oxygen vacancies in these films. Post deposition annealing in a H2 ambient is shown to further improve photocurrent in all cases, while annealing in atmosphere leads to uniform film chemistry and enhanced photocurrent stability in all cases.
Reactive force field-based molecular dynamics simulation of the interaction between plasma reactive oxygen species and the receptor-binding domain of the spike protein in the capsid protein of SARS-CoV-2
Authors: Wang Huichao , Zhao Tong , Yang Shuhui , Zou Liang , Wang Xiaolong , Zhang Yuantao
Published: November 2021

Under the pressures of the current global pandemic, researchers have been working hard to find a reliable way to suppress infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and prevent the spread of COVID-19. Studies have shown that the recognition and binding of human angiotensin-converting enzyme 2 by the receptor-binding domain (RBD) of the spike protein on the surface of SARS-CoV-2 is a crucial step in viral invasion of human receptor cells, and blocking this process could inhibit the virus from invading normal human cells. Plasma treatment can disrupt the structure of the RBD and effectively block the binding process. However, the mechanism by which plasma blocks recognition and binding is not clear. In this study, the reaction between reactive oxygen species (ROS) in plasma and a molecular model of the RBD was simulated using a reactive molecular dynamics method. The results showed that the destruction of the RBD by ROS was triggered by hydrogen abstraction reactions: O and OH abstracted H atoms from the RBD, while the H atoms of H2O2 and HO2 were abstracted by the RBD. This hydrogen abstraction resulted in the breakage of C–H, N–H, O–H and C=O bonds and the formation of C=C and C=N bonds. The addition reaction of OH increased the number of O–H bonds and caused the formation of C–O, N–O and O–H bonds. The dissociation of N–H bonds led to the destruction of the original peptide bond structure and amino acid residues, changed the type of amino acid residues and caused the conversion of N–C and N=C and C=O and C–O. The simulation partially elucidated the microscopic mechanism of the interaction between ROS in plasma and the capsid protein of SARS-CoV-2, providing theoretical support for the control of SARS-CoV-2 infection by plasma, a contribution to overcoming the global pandemic.
Multiplicative modified Rodrigues-parameters-based strong tracking unscented Kalman filter for satellite attitude estimation
Authors: Ma Haining , Lu Zhengliang , Zhang Xiang , Liao Wenhe
Published: November 2021

In this paper, an improved strong tracking unscented Kalman filter based on multiplicative modified Rodrigues parameters (MRPs) is proposed for satellite attitude estimation. The multiplicative MRPs are superior to additive MRPs in terms of attitude representation, especially when attitude angles are large. By minimizing the loss function in Wahba’s problem, a novel method of weighted average for MRPs is derived to replace the simple procedure. The generation of Sigma points, update of state variables, and calculation of covariance matrices are all different from the existing literature to maintain the multiplicative property of MRPs. Simulation results by raw telemetry data from the on-orbit CubeSat Enlai-1 demonstrate the excellent performance of the proposed filter under large attitude angles.
Scale adaptive subdomain matching network for bearing fault diagnosis
Authors: Zhang Di , Wei Yuan , Wang Baoqiang , Liu Shulin
Published: November 2021

The wide application of transfer learning technology can effectively solve the problem of the difference between data collection and actual application equipment of traditional intelligent fault diagnosis methods in the practical application process. However, the difference in subdomain space and the serious imbalance of data samples in the process of simultaneous transfer restricts the deep transfer learning technology to the engineering application of high-precision diagnosis. In order to solve the problem of subdomain matching with different subspaces and unbalanced data samples, in this paper we study the subdomain adaptive method and propose a scale adaptive subdomain matching (SASM) method. The SASM method divides the global feature space according to the sample labels, and features with the same label will be divided into the same sub-feature space. Using the edge distribution of the sample and the category weight of the label, the SASM method can effectively optimize the feature distribution of the same subdomain and the weight distribution of different subdomains. Based on the establishment of a clearer internal structure of features, the field adaptation effect is improved, and the matching ability is enhanced when the sample is unevenly distributed. At the same time, the SASM network (SASMN) method for unsupervised bearing fault diagnosis is constructed and validated by experiments. The results indicate that SASMN can effectively optimize the subdomain adaptive effect, and the diagnostic accuracy of the target domain data set is significantly higher than the other three currently popular domain adaptive fault diagnosis methods.
Editorial for focus on nanophase materials for next-generation lithium-ion batteries and beyond
Authors: Meng Xiangbo , Chen Zonghai , Li Jianlin , Harrison Katharine L , Lu Wenquan , Sun Xueliang
Published: November 2021

Lithium-ion batteries (LIBs) have revolutionized our society in many respects, and we are expecting even more favorable changes in our lifestyles with newer battery technologies. In pursuing such eligible batteries, nanophase materials play some important roles in LIBs and beyond technologies. Stimulated by their beneficial effects of nanophase materials, we initiated this Focus. Excitingly, this Focus collects 13 excellent original research and review articles related to the applications of nanophase materials in various rechargeable batteries, ranging from nanostructured electrode materials, nanoscale interface tailoring, novel separators, computational calculations, and advanced characterizations.
Ideal magnetohydrodynamic stability in stellarators with subsonic equilibrium flow
Authors: Nührenberg C
Published: November 2021

The effect of a subsonic flow, inherent to most stellarators because of a radial electric field, on their ideal magnetohydrodynamic (MHD) stability properties is studied employing the quasi-Lagrangian picture developed by Frieman and Rotenberg (1960Rev. Mod. Phys.32898). The Mach number of the perpendicularE × Bflow in stellarators is of order 0.01 and, therefore, admits the usage of a subsonic approximation in form of a static equilibrium. A mathematical formulation of the weak form of the stability equation with flow has been implemented in the ideal-MHD stability code CAS3D. This formulation uses magnetic coordinates and does not involve any derivatives across magnetic surfaces. In addition to the expected Doppler shift of frequencies, properties of the spectrum of the ideal MHD force operator, which are already known for tokamaks, but now also shown in the stellarator case, are: firstly, the appearance of unstable flow-induced continua stemming from the coupling of sound and Alfvén continuum branches with equal mode numbers; and, secondly, the existence of flow-induced, global, stable modes near extrema of sound continuum branches, the extrema, in turn, being generated by the influence of a sheared flow on the static sound continua.
Systematic oxygen impurity reduction in smooth N-polar GaN by chemical potential control
Authors: Szymanski Dennis , Wang Ke , Kaess Felix , Kirste Ronny , Mita Seiji , Reddy Pramod , Sitar Zlatko , Collazo Ramon
Published: November 2021

Process chemical potential control and dislocation reduction were implemented to control oxygen concentration in N-polar GaN layers grown on sapphire substrates via metal organic chemical vapor deposition (MOCVD). As process supersaturation was changed from ∼30 to 3400, the formation energy of the oxygen point defect increased, which resulted in a 25-fold decrease in oxygen incorporation. Reducing dislocations by approximately a factor of 4 (to ∼109 cm−3) allowed for further reduction of oxygen incorporation to the low-1017 cm−3 range. Smooth N-polar GaN layers with low oxygen content were achieved by a two-step process, whereas first a 1 µm thick smooth N-polar layer with high oxygen concentration was grown, followed by low oxygen concentration layer grown at high supersaturation.
Six-fold symmetry origin of Dirac cone formation in two-dimensional materials
Authors: Qin Xuming , Liu Yi , Li Xiaowu , Yang Gui , Zhao Dongqiu , Ju Lin
Published: November 2021

Dirac materials possess many excellent electrical properties, resulting that the search and design of Dirac materials have become a hot research area. Revealing the formation conditions of Dirac cone (DC) can provide theoretical guidance for the search and design of Dirac materials. To obtain the necessary conditions for the formation of DC of two-dimensional (2D) materials with six-fold symmetry (SFS), the DC formation mechanism was analyzed by the ‘divide-and-couple’ approach in the framework of tight-binding theory, confirmed by the subsequent density functional theory calculations. The simple ‘6n + 2’ rule was proposed to determine whether the 2D materials with SFS have DCs, i.e. when the number of atoms in a unit cell is 6n + 2, the systems would possess DCs at the vertex of Brillouin zone for the 2D materials composed of the elements of the IV main group. Moreover, the ‘3n + 1’ rule was derived as the condition for the DC formation in graphene-like silagraphene with SFS and used to design a silagraphene Si6C8 with DCs. Understanding the DC formation mechanism of 2D materials with SFS not only provides theoretical guidance for designing novel Dirac materials but also sheds light on the symmetry origin of the formation mechanism of DC.
Theoretical aspects of radium-containing molecules amenable to assembly from laser-cooled atoms for new physics searches
Authors: Fleig Timo , DeMille David
Published: November 2021

We explore the possibilities for a next-generation electron-electric-dipole-moment experiment using ultracold heteronuclear diatomic molecules assembled from a combination of radium and another laser-coolable atom. In particular, we calculate their ground state structure and their sensitivity to parity- and time-reversal (

P
,
T

) violating physics arising from flavor-diagonal charge-parity (

CP

) violation. Among these species, the largest

P
,
T

-violating molecular interaction constants—associated for example with the electron electric dipole moment—are obtained for the combination of radium (Ra) and silver (Ag) atoms. A mechanism for explaining this finding is proposed. We go on to discuss the prospects for an electron EDM search using ultracold, assembled, optically trapped RaAg molecules, and argue that this system is particularly promising for rapid future progress in the search for new sources of

CP

violation.
Calculation of flow separation in a retarded boundary-layer over a moving continuous sheet
Authors: Mehmood Ahmer , Shah Babar Hussain , Usman Muhammad , Raza Iqrar
Published: November 2021

Theoretical investigations of fundamental boundary-layer flows are always given prime importance in the field of boundary-layer theory. In particular, among the boundary-layer flows occurring on planner geometries, importance had been given to the flows occurring over the surfaces of finite length. The boundary-layer flows due to moving continuous surfaces were introduced about half a century later to the famous Blasius flow. Unfortunately, no significant attention had been given to these flows with regard to the investigation of boundary-layer properties in these flows. Consequently, a great gap has been created between these two important categories of boundary-layer flows. It is a matter of fact that the flows due to moving continuous surfaces are richer in physics; offer favorable impact, and involve interesting technological applications. One of the important hallmarks of these flows is that they offer a significantly increased wall skin-friction as compared to the flows over surfaces of finite length. Therefore these flows appear to be profitable in situations that are more vulnerable to flow separation. To explore this fact the current study considers a variety of retarded wall velocities to calculate the delay in flow separation for the flows due to moving continuous surfaces in comparison to those occurring on a surface of finite length. It is observed that in the flows due to a moving continuous surface the flow separation is greatly delayed in comparison to the flows over surfaces of finite length. Moreover, the role of wall suction velocity, in this regard, is to be further amplified in these flows. Overall, it is concluded that the continuous surfaces are more useful in order to delay flow separation as compared to the surfaces of finite length.
Effect of point defects and nanopores on the fracture behaviors in single-layer MoS2 nanosheets
Authors: Bao Hongwei , Miao Yaping , Ma Fei
Published: November 2021

Point defects and nanopores are inevitable and particularly noticeable in single-layer (SL) MoS2. Molecular dynamics (MD) simulations have been done to comprehensively study the influences of point defects and nanopores on tensile deformation behaviors of SLMoS2 nanosheets, and the dependences of fracture properties on defect type and concentration, pore size, temperature and strain rate are discussed. The formation energy of S vacancy (VS) is the lowest one, but that of VMoS6 is the highest one, corresponding to the highest and lowest fracture stress, respectively. The local stress concentration around point defects and nanopores might lead to the early bond breaking and subsequent nucleation of cracks and brittle fracture upon tensile loading. A modified Griffith criterion is proposed to describe the defect concentration and pore size dependent fracture stress and strain. These findings provide us an important guideline for the structural design of 2D materials in future applications.
Single-molecule imaging of IQGAP1 regulating actin filament dynamics
Authors: Hoeprich Gregory J. , Sinclair Amy N. , Shekhar Shashank , Goode Bruce L.
Published: November 2021

Labeled human IQGAP1 molecules are directly observed binding and regulating actin filament dynamics and spatial organization in real time. These activities depend on combinations of IQGAP1 domains and/or its dimerization status.
SAMBA controls cell division rate during maize development
Authors: Gong Pan , Bontinck Michiel , Demuynck Kirin , De Block Jolien , Gevaert Kris , Eeckhout Dominique , Persiau Geert , Aesaert Stijn , Coussens Griet , Van Lijsebettens Mieke , Pauwels Laurens , De Jaeger Geert , Inzé Dirk , Nelissen Hilde
Published: November 2021

SAMBA has been identified as a plant-specific regulator of the anaphase-promoting complex/cyclosome (APC/C) that controls unidirectional cell cycle progression in Arabidopsis (Arabidopsis thaliana), but so far its role has not been studied in monocots. Here, we show the association of SAMBA with the APC/C is conserved in maize (Zea mays). Two samba genome edited mutants showed growth defects, such as reduced internode length, shortened upper leaves with erect leaf architecture, and reduced leaf size due to an altered cell division rate and cell expansion, which aggravated with plant age. The two mutants differed in the severity and developmental onset of the phenotypes, because samba-1 represented a knockout allele, while translation re-initiation in samba-3 resulted in a truncated protein that was still able to interact with the APC/C and regulate its function, albeit with altered APC/C activity and efficiency. Our data are consistent with a dosage-dependent role for SAMBA to control developmental processes for which a change in growth rate is pivotal.
How Decompression Surgery Improves the Lower Back Pain in Patient with Lumbar Degenerative Stenosis
Authors: Yagi Mitsuru , Suzuki Satoshi , Nori Satoshi , Takahashi Yohei , Tsuji Osahiko , Nagoshi Narihito , Nakamura Masaya , Matsumoto Morio , Watanabe Kota
Published: November 2021

Study Design.

Multicenter retrospective case series of patients treated surgically for lumbar spinal stenosis (LSS)

Objective.

We investigated how laminectomy improves lower back pain (LBP) and the factors associated with poor improvement.

Summary of Background Data.

Lumbar laminectomy is effective for alleviating neurological symptoms caused by LSS, whereas its effect on LBP is still controversial.

Methods.

A retrospective review of prospectively collected data from 436 patients (age 72 yrs, 69% males) who underwent laminectomy for LSS with 2 years of follow-up. We analyzed the following risk factors for residual LBP by uni- and multivariate analyses: age, sex, smoking, occupation, comorbidities, frailty, joint replacement, vertebral fracture, DISH, HRQOL, complications, and the presence of spinal instability. The LBP of male and female patients was analyzed after propensity score matching of known confounders. Patient-reported outcomes (JOABPEQ and VAS scores) were obtained at baseline and the 2-year postoperative follow-up.

Results.

LBP was significantly improved at 2 years post operation (VAS change 2.3 [95% CI 2.0–2.6], P < 0.01). Fifty-five percent of the patients achieved an MCID, with 67% having no or mild LBP. In the multivariate analysis, sex and baseline LBP were independent risk factors (female: OR 1.9 [1.2–3.0], baseline LBP [VAS≥7.5]: OR 1.9 [1.2–3.1]). Furthermore, the independent risk factors for severe baseline LBP were sex and mental status (female: OR 1.7 [1.1–2.7], P = 0.03, mental status: OR 3.8 [2.4–6.0], P < 0.01). However, an analysis of 102 pairs of propensity-score-matched male and female patients showed no difference in the improvement of LBP (male vs. female: VAS 3.8 ± 2.8 vs. 4.0 ± 2.9, P = 0.61, VAS change 3.1 ± 2.9 vs. 2.7 ± 3.0, P = 0.38).

Conclusion.

Decompression surgery for LSS significantly improved LBP. Sex and baseline LBP were risk factors for residual LBP. However, when males and females were matched by confounders, no difference was found in the LBP after surgery. Patients with severe baseline LBP may need further evaluation for their mental status because these patients are likely to have mental problems that potentially contribute to persistent LBP.

Level of Evidence: 4
Ambient air pollution associated with lower academic achievement among US children
Authors: Lu Wenxin , Hackman Daniel A. , Schwartz Joel
Published: November 2021

Background:

Ambient air pollution is an important environmental exposure and has been linked with impaired cognitive function. Few studies have investigated its impact on children’s academic performance on a nationwide level. We hypothesize that higher ambient air pollution concentrations will be associated with lower average academic test scores.

Methods:

We investigated three prevalent ambient air pollutants: PM2.5, NO2 and ozone, and their associations with the average academic test scores, at the Geographic School District (GSD) level, of the third to eighth grade students in the United States from 2010 to 2016. We applied multivariate linear regression and controlled for urbanicity, socioeconomic status, student racial/ethnic compositions, and individual intercepts for each district-grade level and each year.

Results:

We found that an interquartile range increase in PM2.5 concentrations was associated with a 0.007 (95% confidence interval: 0.005, 0.009) SD lower average math test scores, and a 0.004 (95% confidence interval: 0.002, 0.005) SD lower average English language/arts test scores. Similar associations were observed for NO2 and ozone on math, and for NO2 on English language/arts. The magnitudes of these associations are equivalent to the effects of short-term reductions of thousands of dollars in district median household income. The reductions in test scores were larger for GSDs with higher socioeconomic status, though most associations remained negative at all socioeconomic levels.

Conclusions:

Our results show that ambient air pollution within a GSD is associated with lower academic performance among children. Further improving air quality may benefit children’s overall academic achievement and socioeconomic attainment across the lifespan.
Urinary lead level and colonization by antibiotic resistant bacteria
Authors: Eggers Shoshannah , Safdar Nasia , Kates Ashley , Sethi Ajay K. , Peppard Paul E. , Kanarek Marty S. , Malecki Kristen M. C.
Published: November 2021

Background:

Infection by antibiotic resistant bacteria (ARB) is a global health crisis and asymptomatic colonization increases risk of infection. Nonhuman studies have linked heavy metal exposure to the selection of ARB; however, few epidemiologic studies have examined this relationship. This study analyzes the association between urinary lead level and colonization by ARB in a nonclinical human population.

Methods:

Data came from the Survey of the Health of Wisconsin 2016–2017, and its ancillary Wisconsin Microbiome Study. Urinary lead levels, adjusted for creatinine, were used to assess exposure. ARB included methicillin resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), fluoroquinolone resistant Gram-negative bacilli (RGNB), and Clostridium difficile (C. diff), from skin, nose, and mouth swabs, and saliva and stool samples. Logistic regression, adjusted for covariates, was used to evaluate associations between Pb and ARB. Secondary analysis investigated Pb resistance from ARB isolates.

Results:

Among 695 participants, 239 (34%) tested positive for ARB. Geometric mean urinary Pb (unadjusted) was 0.286 µg/L (95% confidence intervals [CI] = 0.263, 0.312) for ARB negative participants and 0.323 µg/L (95% CI = 0.287, 0.363) for ARB positive participants. Models adjusted for demographics, diet, and antibiotic use showed elevated odds of positive colonization for those in the 95th percentile (vs. below) of Pb exposure (odds ratio [OR] = 2.05, 95% CI = 0.95, 4.44), and associations were highest in urban residents (OR = 2.85, 95% CI = 1.07, 7.59). RGNB isolates were most resistant to Pb.

Discussion:

These novel results suggest that Pb exposure is associated with increased colonization by ARB, and that RGNB are particularly resistant to Pb.
CHANGES IN SYSTEMIC LEVELS OF VASCULAR ENDOTHELIAL GROWTH FACTOR AFTER INTRAVITREAL INJECTION OF AFLIBERCEPT OR BROLUCIZUMAB FOR NEOVASCULAR AGE-RELATED MACULAR DEGENERATION
Authors: Angermann Reinhard , Huber Anna Lena , Nowosielski Yvonne , Salcher Stefan , Gasser Thomas , Seifarth Christof , Kralinger Martina T. , Zehetner Claus
Published: November 2021

Purpose:

To analyze and compare the effects of intravitreal brolucizumab versus aflibercept on systemic vascular endothelial growth factor (VEGF)-A levels in patients with neovascular age-related macular degeneration.

Methods:

In this prospective interventional case series study, brolucizumab (6.0 mg/50 µL) or aflibercept (2.0 mg/50 µL) was injected intravitreally in 30 patients each. Blood samples were drawn at baseline and 7 days and 28 days after the first injection. Systemic VEGF-A levels were measured using enzyme-linked immunosorbent assay. Thirty healthy individuals served as controls.

Results:

The median baseline systemic VEGF-A levels in the brolucizumab, aflibercept, and control groups were 10.8 (8.0–13.2), 12.0 (8.0–18.5), and 10.0 (8.0–15.1) pg/mL, respectively (P = 0.315). In the brolucizumab group, VEGF-A levels significantly decreased to 8.0 (8.0–11.5) pg/mL on Day 7 (P = 0.0254) and to 8.0 (8.0–8.0) pg/mL on Day 28 (P < 0.001). In the aflibercept group, VEGF-A levels significantly decreased to 8.0 (8.0–8.0) pg/mL on Day 7 (P < 0.001) but returned to the baseline level, 12.5 (8.5–14.6) pg/mL, on Day 28 (P = 0.120). Vascular endothelial growth factor–A levels were significantly different between the treatment groups after 28 days (P < 0.001).

Conclusion:

Intravitreal brolucizumab resulted in a sustained reduction of systemic VEGF-A levels until 28 days posttreatment, which raises concerns regarding its safety and long-term effects.
Infective Necrotizing Scleritis After XEN Gel Stent With Mitomycin-C
Authors: Kingston Ezekiel J. , Zagora Sophia L. , Symes Richard J. , Raman Pushpa , McCluskey Peter J. , Lusthaus Jed A.
Published: November 2021

Purpose:

The purpose of this study was to report a case of infective necrotizing scleritis following XEN Gel Stent with mitomycin-C.

Methods:

Case report. This is a case report of a 68-year-old woman.

Results:

XEN Gel Stent glaucoma surgery enhanced with mitomycin-C 0.04% and combined with cataract surgery was performed at a regional center to manage the patient’s primary open-angle glaucoma. Past medical history was significant for rheumatoid arthritis requiring treatment with methotrexate and adalimumab. Periocular pain and swelling developed 14 months after the initial operation, followed by a rapid deterioration of visual acuity to 20/60, intraocular pressure of 4 mm Hg, and worsening pain 5 months later. On initial presentation to Sydney Eye Hospital, 180 degrees of scleral necrosis was evident with a moderate anterior segment inflammatory reaction and a large temporal choroidal effusion due to hypotony. Empirical hourly topical ofloxacin and cephalothin 5% drops, with oral moxifloxacin, were initiated. Conjunctival swab grew Staphylococcus aureus and Staphylococcus lugdunensis. Significant clinical improvement occurred, but the XEN Gel Stent became exposed after 9 days of treatment with worsening hypotony. Urgent surgical revision was performed to remove the XEN Gel Stent and apply a tutoplast plug with overlying amniotic membrane graft. Intraocular pressure gradually improved over 6 weeks to 15 mm Hg with reversal of hypotonous changes, and visual acuity stabilized at 20/40.

Conclusions:

To our knowledge, this is the first reported case of necrotizing scleritis following XEN Gel Stent insertion. It is a reminder that infection should always be the primary differential diagnosis in patients with surgical-induced necrotizing scleritis.
Interrupted femtosecond laser delivery secondary to face mask–related fogging
Authors: Sachdev Mahipal S. , Malik Raghav , Sachdev Gitansha Shreyas , Heroor Anagha , Thoumungkan Bharat R.
Published: November 2021

Introduction:

An increase in face mask utilization has been noted during the COVID-19 pandemic. A rare complication of keratorefractive surgery where interruption of femtosecond-laser delivery was noted secondary to face-mask related fogging of the patient interface is reported.

Patient and clinical findings:

Young patients with stable tear film and healthy ocular surface were advised femtosecond laser assisted laser in situ keratomileusis (3 eyes) and small-incision lenticule extraction (1 eye) for refractive errors. Intraoperative interruption of laser delivery was noted secondary to droplet condensation or fogging of the patient interface. The fogging developed secondary to the escape of humid exhaled breath.

Diagnosis, intervention, and outcomes:

Incomplete delivery of the laser required aborting the procedure with retreatment at a later date. In eyes where partial laser delivery was obtained, the flap was manually dissected from the underlying stroma and the procedure was completed in the same sitting. All eyes achieved a final uncorrected distance visual acuity of 20/20 with no long-term sequelae.

Conclusions:

Fogging of the patient interface is a rare complication secondary to face mask use. Sealing the top of the face mask with well-adhering micropore, readjustment of face masks, removing the mask prior to draping, and checking for droplet condensates on the interface prior to laser delivery may minimize the incidence.