bluuebunny/crossref_metadata_2025 huggingface dataset:
Spin in Schrödinger-quantized pseudoclassical systems
Authors: Allen Theodore J.
Published: October 2021

We examine the construction of the spin angular momentum in systems with pseudoclassical Grassmann variables. In constrained systems, there are many different algebraic forms for the dynamical variables that will all agree on the constraint surface. For the angular momentum, a particular form of the generators is preferred, which yields superselection sectors of irreducible spinc(n) representations rather than reducible so(n) representations when quantized in the Schrödinger realization.
Influence of direct deposition of dielectric materials on the optical response of monolayer WS2
Authors: Yun Tinghe , Wurdack Matthias , Pieczarka Maciej , Bhattacharyya Semonti , Ou Qingdong , Notthoff Christian , Nguyen Chung Kim , Daeneke Torben , Kluth Patrick , Fuhrer Michael S. , Truscott Andrew G. , Estrecho Eliezer , Ostrovskaya Elena A.
Published: October 2021

We investigate the effects of direct deposition of different dielectric materials (AlOx, SiOx, SiNx) onto atomically thin TMDC WS2 on its optical response using atomic layer deposition (ALD), electron beam evaporation (EBE), plasma-enhanced chemical vapor deposition (PECVD), and magnetron sputtering. The photoluminescence measurements reveal quenching of the excitonic emission after all deposition processes, which is linked to the increased level of charge doping and associated rise of the trion emission and/or the localized (bound) exciton emission. Furthermore, Raman spectroscopy allows us to clearly correlate the observed changes in excitonic emission with the increased levels of lattice disorder and defects. In particular, we show that the different doping levels in a monolayer WS2 capped by a dielectric material are strongly related to the defects in the WS2 crystal introduced by all capping methods, except for ALD. The strong charge doping in the ALD-capped sample seems to be caused by other factors, such as deviations in the dielectric layer stoichiometry or chemical reactions on the monolayer surface, which makes ALD distinct from all other techniques. Overall, the EBE process results in the lowest level of doping and defect densities and in the largest spectral weight of the exciton emission in the PL. Sputtering is revealed as the most aggressive dielectric capping method for WS2, fully quenching its optical response. Our results demonstrate and quantify the effects of direct deposition of dielectric materials onto monolayer WS2, which can provide valuable guidance for the efforts to integrate monolayer TMDCs into functional optoelectronic devices.
Nonlinear resonance decomposition for weak signal detection
Authors: Qiao Zijian , Liu Jian , Xu Xuefang , Yin Anmin , Shu Xuedao
Published: October 2021

This paper attempts to investigate the behaviors of coupling stochastic resonance (CSR) subject to α-stable noise and a periodic signal by using the residence-time ratio. Then, a nonlinear resonance decomposition is designed to successfully enhance and detect weak unknown multi-frequency signals embedded in strong α-stable noise by decomposing the noisy signal into a series of useful resonant components and a residue, where the residence-time ratio, instead of the output signal-to-noise ratio and other objective functions depending on the prior knowledge of the signals to be detected, can optimize the CSR to enhance weak unknown signals. Finally, the nonlinear resonance decomposition is used to process the raw vibration signal of rotating machinery. It is found that the nonlinear resonance decomposition is able to decompose the weak characteristic signal and its harmonics, identifying the imbalance fault of the rotor. Even the proposed method is superior to the empirical mode decomposition method in this experiment. This research is helpful to design the noise enhanced signal decomposition techniques by harvesting the energy of noise to enhance and decompose the useful resonant components from a nonstationary and nonlinear signal.
A novel apparatus for measuring gas solubility in aqueous solution under multiphase conditions by isobaric method
Authors: Wang Tian , Zhang Lunxiang , Sun Lingjie , Zhou Ran , Shi Kangji , Zhao Jiafei
Published: October 2021

With the increasing energy shortage and global warming, the oil/gas development and CO2 sequestration are moving toward the deep sea, and such a geological environment is conducive to gas hydrate formation. At present, for the gas solubility of a hydrate solution system, only Duan’s simulation data are widely accepted, and a systematic experimental study is absent. The conventional measurement instruments for solubility of dissolved gas lack control of hydrate phase change, detailed regulation of temperature and pressure, and liquid–solid separation of sampling analysis. This paper describes the working principle, design, and use of a novel apparatus that can measure gas solubility in the solution system in the presence of hydrate. The application of constant pressure equipment avoids disturbing the phase equilibrium and dissolution equilibrium of the system in the sampling process. The apparatus is attractive for the continuous measurement of gas solubility and the guarantee of high accuracy. In addition, an isobaric method is proposed for gas solubility measurement, which promotes the measurement system to reach the target equilibrium state quickly and obtains highly regular data of gas solubility under environmental conditions. The experimental data obtained by this work are highly consistent with the Duan model, and the relative errors of measurements are within 2%. Gas solubility data from this apparatus will provide theoretical support for estimation of the marine CO2 sequestration capacity and prevention of hydrate blockage in oil/gas transportation.
Underscreening and hidden ion structures in large scale simulations of concentrated electrolytes
Authors: Krucker-Velasquez Emily , Swan James W.
Published: October 2021

The electrostatic screening length predicted by Debye–Hückel theory decreases with increasing ionic strength, but recent experiments have found that the screening length can instead increase in concentrated electrolytes. This phenomenon, referred to as underscreening, is believed to result from ion–ion correlations and short-range forces such as excluded volume interactions among ions. We use Brownian Dynamics to simulate a version of the Restrictive Primitive Model for electrolytes over a wide range of ion concentrations, ionic strengths, and ion excluded volume radii for binary electrolytes. We measure the decay of the charge–charge correlation among ions in the bulk and compare it against scaling trends found experimentally and determined in certain weak coupling theories of ion–ion correlation. Moreover, we find that additional large scale ion structures emerge at high concentrations. In this regime, the frequency of oscillations computed from the charge–charge correlation function is not dominated by electrostatic interactions but rather by excluded volume interactions and with oscillation periods on the order of the ion diameter. We also find the nearest neighbor correlation of ions sharing the same charge transitions from negative at small concentrations to positive at high concentrations, representing the formation of small, like-charge ion clusters. We conclude that the increase in local charge density due to the formation of these clusters and the topological constraints of macroscopic charged surfaces can help explain the degree of underscreening observed experimentally.
On the dissipative extended Kawahara solitons and cnoidal waves in a collisional plasma: Novel analytical and numerical solutions
Authors: El-Tantawy S. A. , Salas Alvaro H. , Alharthi M. R.
Published: October 2021

Two novel analytical solutions to the damped Gardner Kawahara equation and its related equations are reported. Using a suitable ansatz and with the help of the exact solutions of the undamped Gardner Kawahara equation, two general high-accurate approximate analytical solutions are derived. Moreover, the Crank–Nicolson implicit finite difference method is introduced for analyzing the evolution equation numerically. The comparison between the obtained solutions is examined. All the obtained solutions are able to investigate many types of the dissipative traveling wave solutions such as the dissipative solitary and cnoidal waves. Also, the obtained solutions help many researchers understand the mechanisms underlying a variety of nonlinear phenomena that can propagate in optical fiber, physics of plasmas, fluid mechanics, water tank, oceans, and seas. The obtained solutions could be applied for investigating the characteristics of the dissipative higher-order solitary and cnoidal waves in electronegative plasmas. Numerical results depending on the physical plasma parameters are presented.
Influence of oxygen adsorption from atmosphere on surface tension of liquid silicon
Authors: Ozawa Shumpei , Nagasaka Yosuke , Itakura Masahiro , Sugisawa Kota , Seimiya Yusaku
Published: October 2021

Influences of temperature and oxygen adsorption on the surface tension of liquid silicon were investigated by the oscillating droplet method using the electromagnetic levitation technique. Oxygen partial pressure in the vicinity of the liquid surface was controlled by the theoretically derived Ratto, Ricci, and Arato model and the effectiveness of which was experimentally confirmed from the in situ observation of oxidation and reduction behaviors of the droplet surface in this study. The surface tension of liquid silicon was decreased with increasing oxygen partial pressure in the vicinity of the liquid surface due to oxygen adsorption at low temperature, whereas the surface tension converged to a pure state value at high temperature regardless of the oxygen partial pressure due to a decrease in the equilibrium constant of oxygen adsorption reaction. As a result, “boomerang shape” temperature dependence of surface tension was observed; the gradient of the temperature dependence of surface tension was gradually increased with elevating temperature and then became a constant value at high temperature. The influences of oxygen adsorption and temperature on surface tension were successfully derived from the measurement result by using the Szyszkowski equation. Furthermore, the changes in enthalpy and entropy for oxygen adsorption on liquid silicon were also estimated.
Multiplicity for idealized rotational detonation waves
Authors: Zhang Peiyu , Meagher Patrick A. , Zhao Xinyu
Published: October 2021

Simulations of three-dimensional rotational detonation waves are conducted to understand the mechanisms of wave bifurcation. A compressible reacting Euler solver is developed within the framework of OpenFOAM, and a fixed mass flux boundary condition is developed to avoid complex injector dynamics. Influences of inflow mass flow rates and initiations of ignition spots are studied. As the inflow mass flow rate increases, one detonation wave is maintained. Constrained by the circumference of the combustor, the maximum fill height is achieved when the maximum post-shock pressure expansion is reached. Further increasing mass flow rates does not lead to wave bifurcation or higher mean fill height. By introducing multiple ignition regions, an identical number of stable waves are ignited and maintained, which signifies that wave numbers are not uniquely determined by the inlet boundary conditions. The minimum fill height (or largest velocity deficit) owing to either the lowest mass flow rate or the maximum wave number is obtained when the pressure expansion distance is comparable to the hydrodynamic thickness. The scaling of fill height is subsequently explained through a theoretical relation based on mass conservation. It is shown that neither increasing mass flow rates nor existence of multiple waves is a sufficient condition for wave bifurcation. The fill height is intrinsically connected with wave numbers, and both cannot be predicted solely based on boundary conditions. Future work will relax some idealizations in this work to further quantify the limit for the fill height.
Self-organized confinement in whole-device modeling of laboratory magnetospheres
Authors: Li Bo , Wang Lipeng , Ou Weike , Zhou Zhenyu , Li Zhuoyi , Rogers Barrett N. , Mauel M. E.
Published: October 2021

Turbulent self-organization driven by global ideal interchange modes in a dipole-confined plasma is explored with self-consistent, whole-plasma simulations using a flux-tube averaged magnetohydrodynamic model in dipole magnetic geometry. We show the existence of robust particle pinch driven by ideal interchange-mode fluctuations, in which the particles are transported up the density gradient. It is found that the plasma profiles in a dipole field spontaneously relax to a marginally stable state as centrally peaked pressure and density are created by global interchange-mode transport.
Near-field scanning optical microscopy of molecular aggregates: The role of light polarization
Authors: Nayak Sidhartha , Zheng Fulu , Eisfeld Alexander
Published: October 2021

We consider theoretically near-field absorption spectra of molecular aggregates stemming from a scattering scanning near-field optical microscopy type setup. Our focus is on the dependence on the direction and polarization of the incoming electromagnetic radiation, which induces a Hertz dipole with a specific orientation at the tip-apex. Within a simple description, which is based on the eigenstates of the aggregate, absorption spectra are calculated for the near field created by this dipole. We find that the spatial patterns of the spectra have a strong dependence on the orientation of this tip-dipole, which can be understood by considering three basic functions that only depend on the arrangement of the aggregate and the molecule tip distance, but not on the orientation of the tip-dipole. This allows direct access to spatial dependence of the aggregate eigenstates. For the important cases of one- and two-dimensional systems with parallel molecules, we discuss these spectra in detail. The simple numerically efficient approach is validated by a more detailed description where the incoming radiation and the interaction between the tip and molecules are explicitly taken into account.
Optimizing photovoltaic conversion of solar energy
Authors: Tawalare P. K.
Published: October 2021

The importance of solar energy can never be over-emphasized. Photovoltaic conversion is the most convenient method for harnessing solar energy. The demand for solar electricity has been increasing in this power hungry world. This has challenged the existing technology for solar power and motivated researchers to find innovative solutions. High cost and high technology have always been highlighted in the context of solar photovoltaics. Due to high cost, during the initial period, solar cells could be employed only in high end applications such as space technology. For widespread use of solar cells, it is imperative to bring the cost of harnessing solar energy down to an affordable level. Efforts taken for over more than 50 years on this topic are reviewed in this paper. These include the search for low cost materials and technology, using amorphous, nanocrystalline materials or thin films, and efforts to increase the conversion efficiency. The concept of spectrum modification is the most ingenious scheme for increasing the efficiency, which ultimately can help bring down the cost.
Vortex-induced vibrations of two rigidly coupled circular cylinders of unequal diameters at low Reynolds number
Authors: Ping Huan , Zhu Hongbo , Zhang Kai , Zhou Dai , Bao Yan , Han Zhaolong
Published: October 2021

Two-dimensional numerical computations are carried out for two rigidly connected cylinders of unequal sizes undergoing vortex-induced vibrations (VIV) perpendicular to the free stream. Results are examined for Re = 250 and a fixed diameter ratio of d/D=0.2. The VIV response of the system is investigated for various positions of the small cylinder, covering a fine grid of wide radial (r) and azimuthal (θ) ranges, relative to the origin of the main cylinder. It is shown that the structural dynamics and hydrodynamic forces are strongly dependent on the arrangements. Regions of VIV reduction and amplification are distinguished, and the highest and lowest oscillation amplitudes are, respectively, acquired at configurations of (r,θ)=(0.7D,90°) and (r,θ)=(0.88D,130°). A deeper analysis in terms of the wake topology and surface pressure is then provided for these two extreme cases, to figure out the underlying mechanisms that lead to such markedly distinct responses. For the former case, the shear layers from two cylinders intensely interact and amalgamate during the oscillation, setting off subsequent processes of shear layer reattachment and downflow that are responsible for the observed high-amplitude response, while for the latter case, the shear layers from the small cylinder are highly stretched and absent from direct interaction with that from the large cylinder, which is favorable for stabilizing the wake and maintaining the low-amplitude response. Proper orthogonal decomposition (POD) is further utilized to correlate the key features of the wake with the dominant coherent structures in the flow.
Temperature-dependent characteristics for the p-type CuO gate HEMT and high-k HfO2 MIS-HEMT on the Si substrates
Authors: Zhao Yaopeng , Wang Chong , Zheng Xuefeng , He Yunlong , Ma Xiaohua , Liu Kai , Li Ang , Hao Yue
Published: October 2021

This work presents the temperature-dependent characteristics of the thin-barrier Al0.45Ga0.55N/GaN high electron mobility transistor (HEMT), p-type CuO gate HEMT, and high-k HfO2 metal–insulator–semiconductor HEMT (MIS-HEMT). As the temperature rises from 20 to 300 °C, the maximum trans-conductance of the HfO2 MIS-HEMT and CuO gate HEMT reduces by 56.9% and 43.2%, respectively. The sub-threshold swing of the CuO gate HEMT is smaller than that of the HfO2 device when the temperature reaches 300 °C. According to the C–V test results from 20 to 300 °C, the relative dielectric constant of CuO increases from 18.1 to 47.4, whereas HfO2 has a relatively stable dielectric constant. The calculation models are presented to investigate the effect of the dielectric constant on the drain current and the trans-conductance. The calculated results show that the maximum transconductance of the HfO2 MIS-HEMT and CuO gate HEMT decreases by 52.3% and 38.9%, respectively, which is in good agreement with the experimental results.
Degradation mechanism of Schottky P-GaN gate stack in GaN power devices under neutron irradiation
Authors: Sun Ruize , Chen Xinghuan , Liu Chao , Chen Wanjun , Zhang Bo
Published: October 2021

In this Letter, the degradation mechanism of Schottky p-type GaN (P-GaN) gate stack in GaN power devices under neutron irradiation is studied. After 1-MeV neutron irradiation at fluences of 6 × 1013 and 1 × 1014 neutron/cm2, device threshold voltage VTH is positively shifted and gate leakage current is increased, which indicates the degradation of Schottky P-GaN gate stack. By analyzing the gate current with Frenkel–Poole emission model, barrier height of Schottky P-GaN gate stack is reduced due to the traps induced by neutron irradiation. By employing capacitance–voltage (C–V) and pulse current–voltage (I–V) measurements, we find that the electron and hole traps induced by displacement damages dominate the degradation of gate characteristics after neutron irradiation. Electron traps at EC- (0.38–0.55) eV and hole traps at EV+ (0.56–0.62) eV with a density of 1011–1012 cm−2 eV−1 are shown in irradiated devices. Ionizations of VGa and Gai induced by neutron radiation as well as their interaction with dislocations significantly alter the energy band of P-GaN/AlGaN/GaN heterostructure gate stack. The trapping and de-trapping processes of VGa-related electron traps lead to positive shifts in VTH. Passivation of dislocations by Gai effectively lowers the barrier height for holes and increases the gate leakage current. Measures to improve the quality of P-GaN/AlGaN/GaN heterostructure or raise the potential barrier height can be taken to make the device more resistant to neutron radiation. This work depicts the physical process and mechanism of degradations in Schottky P-GaN gate stack, which can provide deeper insights into the analysis and field application of GaN power devices under neutron irradiation.
Infrared spectroscopy of the protonated HCl dimer and trimer
Authors: Wagner J. Philipp , McDonald David C. , Colley Jason E. , Franke Peter R. , Duncan Michael A.
Published: October 2021

The protonated HCl dimer and trimer complexes were prepared by pulsed discharges in supersonic expansions of helium or argon doped with HCl and hydrogen. The ions were mass selected in a reflectron time-of-flight spectrometer and investigated with photodissociation spectroscopy in the IR and near-IR regions. Anharmonic vibrational frequencies were computed with VPT2 at the MP2/cc-pVTZ level of theory. The Cl–H stretching fundamentals and overtones were measured in addition to stretch–torsion combinations. VPT2 theory at this level confirms the proton-bound structure of the dimer complex and provides a reasonably good description of the anharmonic vibrations in this system. The trimer has a HCl–HClH+–ClH structure in which a central chloronium ion is solvated by two HCl molecules via hydrogen bonding. VPT2 reproduces anharmonic frequencies for this system, including several combinations involving core ion Cl–H stretches, but fails to describe the relative band intensities.
Pre-breakdown processes in water under ultra-long pulses: Bubble–streamer dynamics and their transition
Authors: Li Xian-dong , He Hua , Xiao Tian-Fei , Xiong Ding , Li Jian
Published: October 2021

Pre-breakdown processes in water are usually accompanied by the developments of bubble and streamer. Therefore, the dynamic behaviors of bubble and streamer and their transition process are essential to understand the mechanism of underwater discharge. In this work, the pre-breakdown processes in water (60 μS/cm) under ultra-long pulses (>100 ms) are investigated, and two fundamental but unclear issues are clarified: What is the intrinsic difference between bubble and streamer, and how does a bubble transit into a streamer? The research results manifest that the pre-breakdown processes under ultra-long pulses follow the pattern of bubble cycle evolution and streamer triggered breakdown, and the final breakdown occurs only if the bubble attached to the electrode surface expands to a critical size (0.5–1.2 mm). Further analysis indicates that the huge conductivity disparity between bubble and streamer leads to their diverse dynamic behaviors. The development of bubble belongs to bottom-up type that the growth of bubble is driven by the expansion of its root near the electrode surface. Meanwhile, the development of streamer belongs to top-down type that the propagation of streamer is guided by the evolvement of its head. As the bubble expands, the voltage drops and pressure of bubble increases and decreases, respectively, which provides a necessary condition for the internal breakdown of bubble triggering the bubble–streamer transition. However, the transition from bubble to streamer is a competitive process: The dynamic equilibrium between growth and expansion (development boost) and detachment/rupture (development resistance) of bubble determines whether the bubble can develop continuously into a streamer.
Effect of graphitic anode surface functionalization on the structure and dynamics of electrolytes at the interface
Authors: Rustam Sabiha , Intan Nadia N. , Pfaendtner Jim
Published: October 2021

Surface termination on a graphitic surface and the type of electrolytes in lithium-ion batteries (LIBs) play an important part in determining the structure, composition, and thus, the quality of the emergent solid electrolyte interphase. In this paper, we analyze the structure and dynamics of electrolyte molecules in multi-component electrolyte with varying species compositions combinatorially paired with four different graphitic surfaces terminated with hydrogen, hydroxyl, carbonyl, and carboxyl to explore the interplay between surface chemistry and electrolyte dynamics at electrode/electrolyte interfaces. Addition of dimethyl carbonate and fluoroethylene carbonate brought substantial changes in the ethylene carbonate (EC) and LiPF6 surface population density for hydroxyl and carbonyl surfaces. Strong density oscillation and drastic slowing of the dynamics of the electrolyte molecules at the interface are reported for all the systems. While these observations are universal, carboxyl surfaces have the strongest local and long-range effects. Characterization of the average dipole direction at the interface shows strong orientational preferences of ethylene carbonate molecules. EC molecules are preferred to be oriented either almost parallel or perpendicular to the hydroxyl surface, are tilted between parallel and perpendicular with a higher angle of incidence of the dipole vs surface normal on the carbonyl surface than on the hydroxyl surface, and are oriented perpendicularly against the carboxyl surface. These differences highlight the significant effect of graphite surface termination on the dynamics of the electrolytes and provide insight into the complex interplays between electrolyte species and graphite anode in LIBs.
Breakthrough instruments and products: Lattice Lightsheet 7—Non-invasive imaging of the subcellular dynamics of life
Authors: Elgass K. , Hartmann D. , Siebenmorgen J. , Kalkbrenner T. , Weisshart K.
Published: October 2021

Light sheet fluorescence microscopy has become an established method for fast and sensitive imaging of living specimens with minimum phototoxicity and photobleaching. By adding lattice structures to the light sheet, the ZEISS Lattice Lightsheet 7 makes this technique available for live cell imaging at subcellular resolution while also allowing microscopists to use their standard sample carriers.
Development of hand-held needle–ring–ring self-excited plasma device
Authors: Li Hua , Zhang Yuhan , Meng Linbo , Du Xiaoxia , Xiao Wenxiang
Published: October 2021

Copper is deposited in the holes of two perforated printed circuit boards to form copper rings with a width of 1.5 mm, a thickness of 1.6 mm, and diameters of 10 and 7 mm, respectively. The resulting structures form ground electrodes. A plate with a diameter of 10 mm is placed above a plate with a diameter of 7 mm to ensure that the distance between the two electrode rings is 2.5 mm. Meanwhile, a tungsten needle with a diameter of 1.1 mm is placed 6 mm directly above the coaxial position of the 7 mm diameter plate as the needle electrode. The needle–ring–ring electrode structure is designed to achieve stable synchronous discharge from each unit. The shell of the device is made using 3D printing technology. The displacement of active substances on the agar plate by the needle–ring–ring self-excited plasma jet is visualized using the starch–potassium iodide reagent. The results indicate that the device produces a better sterilization effect than traditional sterilizing devices and that no hollow, annular, unsterilized part is produced. In addition, the macroscopic temperature of the self-excited emission stream is detected. The human body detects no obvious burning or tactile sensation from the plasma.
A Bayesian neural network predicts the dissolution of compact planetary systems
Authors: Cranmer Miles , Tamayo Daniel , Rein Hanno , Battaglia Peter , Hadden Samuel , Armitage Philip J. , Ho Shirley , Spergel David N.
Published: October 2021

Significance

Despite over 300 y of effort, no solutions exist for predicting when a general planetary configuration will become unstable. We introduce a deep learning architecture to push forward this problem for compact systems. While current machine learning algorithms in this area rely on scientist-derived instability metrics, our new technique learns its own metrics from scratch, enabled by a internal structure inspired from dynamics theory. Our model can quickly and accurately predict instability timescales in compact multiplanet systems, and does so with an accurate uncertainty estimate for unfamiliar systems. This opens up the development of fast terrestrial planet formation models, and enables the efficient exploration of stable regions in parameter space for multiplanet systems.
Surface densities prewet a near-critical membrane
Authors: Rouches Mason , Veatch Sarah L. , Machta Benjamin B.
Published: October 2021

Significance

Proteins capable of separating into three-dimensional liquid droplets in the cytoplasm and nuclei of cells sometimes assemble in a two-dimensional form at membranes. These surface densities, enriched in specific proteins and lipids, often play decisive roles in cell signaling and membrane organization. Here a theoretical approach suggests that surface densities resemble prewet surface phases held together through a combination of two-dimensional membrane-mediated forces and three-dimensional protein interactions. The emergent physics of these liquid surface phases enable their roles both as dynamic scaffolds and as cooperative switches that propagate signals between the membrane and bulk.
Ultrasensitive multispecies spectroscopic breath analysis for real-time health monitoring and diagnostics
Authors: Liang Qizhong , Chan Ya-Chu , Changala P. Bryan , Nesbitt David J. , Ye Jun , Toscano Jutta
Published: October 2021

Significance

Determining the identity and concentration of the molecules present in breath is a powerful tool to assess the overall health of a person, analogous to blood testing in clinical medicine, but in a faster and less invasive manner. The presence of a particular molecule (or combination of molecules) can indicate the presence of a certain health condition or infection, facilitating a diagnosis. Monitoring the concentration of the molecules of interest over time can help track the development (or recurrence) of a condition, as well as the effectiveness of the administered treatment. To make breath analysis more accessible and widely adopted, we explore a technique to perform breath analysis with high resolution, wide spectral coverage, high specificity, and high sensitivity.
Constitutive signal bias mediated by the human GHRHR splice variant 1
Authors: Cong Zhaotong , Zhou Fulai , Zhang Chao , Zou Xinyu , Zhang Huibing , Wang Yuzhe , Zhou Qingtong , Cai Xiaoqing , Liu Qiaofeng , Li Jie , Shao Lijun , Mao Chunyou , Wang Xi , Wu Jihong , Xia Tian , Zhao Li-Hua , Jiang Hualiang , Zhang Yan , Xu H. Eric , Cheng Xi , Yang Dehua , Wang Ming-Wei
Published: October 2021

Significance

The mechanism of functional changes induced by alternative splicing of GHRHR is largely unknown. Here, we demonstrate that GHRH-elicited signal bias toward β-arrestin recruitment is constitutively mediated by SV1. The cryogenic electron microscopy structures of SV1 and molecular dynamics simulations reveal the different functionalities between GHRHR and SV1 at the near-atomic level (i.e., the N termini of GHRHR and SV1 differentiate the downstream signaling pathways, G
s
versus β-arrestins). Our findings provide valuable insights into the functional diversity of class B1 GPCRs that may aid in the design of better therapeutic agents against certain cancers.
Highly active engineered IgG3 antibodies against SARS-CoV-2
Authors: Kallolimath Somanath , Sun Lin , Palt Roman , Stiasny Karin , Mayrhofer Patrick , Gruber Clemens , Kogelmann Benjamin , Chen Qiang , Steinkellner Herta
Published: October 2021

Monoclonal antibodies (mAbs) that efficiently neutralize SARS-CoV-2 have been developed at an unprecedented speed. Notwithstanding, there is a vague understanding of the various Ab functions induced beyond antigen binding by the heavy-chain constant domain. To explore the diverse roles of Abs in SARS-CoV-2 immunity, we expressed a SARS-CoV-2 spike protein (SP) binding mAb (H4) in the four IgG subclasses present in human serum (IgG1-4) using glyco-engineered
Nicotiana benthamiana
plants. All four subclasses, carrying the identical antigen-binding site, were fully assembled in planta and exhibited a largely homogeneous xylose- and fucose-free glycosylation profile. The Ab variants ligated to the SP with an up to fivefold increased binding activity of IgG3. Furthermore, all H4 subtypes were able to neutralize SARS-CoV-2. However, H4-IgG3 exhibited an up to 50-fold superior neutralization potency compared with the other subclasses. Our data point to a strong protective effect of IgG3 Abs in SARS-CoV-2 infection and suggest that superior neutralization might be a consequence of cross-linking the SP on the viral surface. This should be considered in therapy and vaccine development. In addition, we underscore the versatile use of plants for the rapid expression of complex proteins in emergency cases.
Nanoconfinement of microvilli alters gene expression and boosts T cell activation
Authors: Aramesh Morteza , Stoycheva Diana , Sandu Ioana , Ihle Stephan J. , Zünd Tamara , Shiu Jau-Ye , Forró Csaba , Asghari Mohammad , Bernero Margherita , Lickert Sebastian , Kotowski Mateusz , Davis Simon J. , Oxenius Annette , Vogel Viola , Klotzsch Enrico
Published: October 2021

Significance

Microvilli are used by immune cells to sense the surface features of pathogens and antigen presenting cells. However, microvilli’s contribution in T cell signaling and activation is largely unknown. Here, we introduce a material-based platform for induction of microvilli formation in T cells, in which the dimensions of the microvilli can be controlled by tuning the dimensions of the nanotopographical features, such as pore depth, pore size, and interpore distance. We demonstrate the direct causality between microvilli formation and altered gene expression in T cells. We discover that the size of the microvilli critically influences T cell receptor agonistic independent signaling in T cells. The results provide a physical strategy for T cell activation and expansion for immunotherapy applications.
Listeriolysin S: A bacteriocin from
Listeria monocytogenes
that induces membrane permeabilization in a contact-dependent manner
Authors: Meza-Torres Jazmín , Lelek Mickaël , Quereda Juan J. , Sachse Martin , Manina Giulia , Ershov Dmitry , Tinevez Jean-Yves , Radoshevich Lilliana , Maudet Claire , Chaze Thibault , Giai Gianetto Quentin , Matondo Mariette , Lecuit Marc , Martin-Verstraete Isabelle , Zimmer Christophe , Bierne Hélène , Dussurget Olivier , Cossart Pascale , Pizarro-Cerdá Javier
Published: October 2021

Significance

Listeria monocytogenes
(
Lm
) is a bacterial pathogen that causes listeriosis, a foodborne disease characterized by gastroenteritis, meningitis, bacteremia, and abortions in pregnant women. The most severe human listeriosis outbreaks are associated with a subset of
Lm
hypervirulent clones that encode the bacteriocin Listeriolysin S (LLS), which modifies the gut microbiota and allows efficient
Lm
gut colonization and invasion of deeper organs. Our present work identifies the killing mechanism displayed by LLS to outcompete gut commensal bacteria, demonstrating that it induces membrane permeabilization and membrane depolarization of target bacteria. Moreover, we show that LLS is a thiazole/oxazole–modified microcin that displays a contact-dependent inhibition mechanism.
Chirality-matched catalyst-controlled macrocyclization reactions
Authors: Hwang Jaeyeon , Mercado Brandon Q. , Miller Scott J.
Published: October 2021

Significance

Chiral catalysts are generally used to control stereochemistry in organic reactions. Generally, they control enantioselectivity or diastereoselectivity. In recent years, applications have expanded to include control over site selectivity in reactions involving complex molecules. Even more rarely, they can control chemoselectivity along with stereochemistry. We report herein that a carefully chosen chiral catalyst can also be decisive for efficient macrocyclization reactions in cases where simple achiral catalysts or stereochemically mismatched catalysts fail. Notably, in these reactions, a chiral catalyst proves essential for control of a reaction in which no new static (i.e., not “dynamic”) stereogenic elements are introduced. While fundamentally intriguing, these observations could also influence strategies for efficient synthesis of macrocyclic compounds in a variety of settings.
The influence of L1 translation familiarity on the acquisition of L2 Chinese antonyms
Authors: Yang Shuyi
Published: October 2021

As a partial replication ofTagashira, Kida, and Hoshino (2010), the present study examined first language (L1) translation familiarity effect on second language (L2) antonym acquisition among English-speaking intermediate-level Chinese learners. Fifteen students learned 15 antonymous pairs with familiar or unfamiliar L1 translations and completed two multiple-choice posttests. Their learning strategies were also collected. Results showed (a) a delayed L1 familiarity effect, (b) better retention and lower interference of L2 pairs with familiar L1 translations, (c) low retention of L2 pairs with unfamiliar L1 translations for both words, and (d) more orthographic elaboration strategies employed. The findings suggest that L2 instructors present antonyms in pairs, avoid providing a single, unfamiliar L1 translation, and encourage the use of orthographic elaboration strategies.
Minibrain kinase and calcineurin coordinate activity-dependent bulk endocytosis through synaptojanin
Authors: Peng Yi-Jheng , Geng Junhua , Wu Ying , Pinales Cristian , Langen Jennifer , Chang Yen-Ching , Buser Christopher , Chang Karen T.
Published: October 2021

Neurons use multiple modes of endocytosis, including clathrin-mediated endocytosis (CME) and activity-dependent bulk endocytosis (ADBE), during mild and intense neuronal activity, respectively, to maintain stable neurotransmission. While molecular players modulating CME are well characterized, factors regulating ADBE and mechanisms coordinating CME and ADBE activations remain poorly understood. Here we report that Minibrain/DYRK1A (Mnb), a kinase mutated in autism and up-regulated in Down’s syndrome, plays a novel role in suppressing ADBE. We demonstrate that Mnb, together with calcineurin, delicately coordinates CME and ADBE by controlling the phosphoinositol phosphatase activity of synaptojanin (Synj) during varying synaptic demands. Functional domain analyses reveal that Synj’s 5′-phosphoinositol phosphatase activity suppresses ADBE, while SAC1 activity is required for efficient ADBE. Consequently, Parkinson’s disease mutation in Synj’s SAC1 domain impairs ADBE. These data identify Mnb and Synj as novel regulators of ADBE and further indicate that CME and ADBE are differentially governed by Synj’s dual phosphatase domains.
The origin of the large magnetoelectric coupling in the ceramic Ba0.1Bi0.9(Ti0.9Zr0.1)0.1Fe0.9O3
Authors: Kallel Imen , Khemakhem Hamadi , Sassi Zina , Abdelmoula Najmeddine , Hlil El-Kebir , Randrianantoandro Nirina
Published: October 2021

57Fe Mössbauer spectrometry and x-ray powder diffraction are conducted to examine the structure and the local magnetic order at the level of Fe sites of Ba0.1Bi0.9(Ti0.9Zr0.1)0.1Fe0.9O3 ceramic. The Mössbauer spectra in the temperature range of 77 K–623 K were analyzed using a discrete distribution of hyperfine field, indicating that the Néel temperature T
N was about 603 K. The ceramic Ba0.1Bi0.9(Ti0.9Zr0.1)0.1Fe0.9O3 remains stable in the rhombohedral structure (R3c) in the temperature range of 300 K–800 K. The anomaly of volume below T
N, as detected from the model Debye–Gruneissen, reveals the presence of magnetoelastic coupling in this compound. The total polarization (P) obtained from Rietveld refined atomic positions is found to depend on the magnetic order that leads to the decrease of the total polarization (P) through the anomaly volume. The reduction in the polarization by ΔP ∼ −2.4 μC cm−2 suggests negative magnetoelectric interaction. The total polarization (P) obtained from Rietveld refined atomic is coupled with the magnetic ordering mediated by magnetoelastic coupling. The hyperfine field (B
hf) dependence of polarization (P) at a temperature range below T
N exhibits a linear evolution, confirming the linear magnetoelectric coupling. At room temperature, the linear magnetoelectric coefficient is about α
ME ≈ 1.84 × 10−9 s m−1.
Optimisation of the total population size with respect to the initial condition for semilinear parabolic equations: two-scale expansions and symmetrisations
Authors: Mazari Idriss , Nadin Grégoire , Toledo Marrero Ana Isis
Published: October 2021

In this article, we propose in-depth analysis and characterisation of the optimisers of the following optimisation problem: how to choose the initial condition u
0 in order to maximise the spatial integral at a given time of the solution of the semilinear equation u

t
−Δu = f(u), under L
∞ and L
1 constraints on u
0? Our contribution in the present paper is to give a characterisation of the behaviour of the optimiser

u

¯

0

when it does not saturate the L
∞ constraints, which is a key step in implementing efficient numerical algorithms. We give such a characterisation under mild regularity assumptions by proving that in that case

u

¯

0

can only take values in the ‘zone of concavity’ of f. This is done using two-scale asymptotic expansions. We then show how well-known isoperimetric inequalities yield a full characterisation of maximisers when f is convex. Finally, we provide several numerical simulations in one and two dimensions that illustrate and exemplify the fact that such characterisations significantly improve the computational time. All our theoretical results are in the one-dimensional case and we offer several comments about possible generalisations to other contexts, or obstructions that may prohibit doing so.
Using periodic boundary conditions to approximate the Navier–Stokes equations on

R3

and the transfer of regularity
Authors: Robinson James C
Published: October 2021

This paper considers solutions u

α
of the three-dimensional Navier–Stokes equations on the periodic domains Q

α
≔ (−α,α)3 as the domain size α → ∞, and compares them to solutions of the same equations on the whole space. For compactly-supported initial data

u

α

0

∈

H

1

(

Q

α

)

, an appropriate extension of u

α
converges to a solution u of the equations on

R

3

, strongly in

L

r

(

0
,
T
;

H

1

(

R

3

)

)

, r ∈ [1, ∞). The same also holds when

u

α

0

is the velocity corresponding to a fixed, compactly-supported vorticity. A consequence is that if an initial compactly-supported velocity

u

0

∈

H

1

(

R

3

)

or an initial compactly-supported vorticity

ω

0

∈

H

1

(

R

3

)

gives rise to a smooth solution on [0, T*] for the equations posed on

R

3

, a smooth solution will also exist on [0, T*] for the same initial data for the periodic problem posed on Q

α
for α sufficiently large; this illustrates a ‘transfer of regularity’ from the whole space to the periodic case.
Recent progress in III-nitride nanosheets: properties, materials and applications
Authors: Wu Kefeng , Huang Siyu , Wang Wenliang , Li Guoqiang
Published: October 2021

As compared with their bulk materials, III-nitride nanosheets, including gallium nitride, aluminium nitride, indium nitride, reveal wider bandgap, enhanced optical properties, anomalously temperature-dependent thermal conductivity, etc, which are more suitable for the fabrication of nano-photodetectors, nano-field electron transistors, etc, for the application in the fields of nano-optoelectronics and nano-electronics. Although the properties of III-nitrides have been predicted based on the first-principles calculation, the experimental realization of III-nitride nanosheets has been restricted primarily due to dangling bonds on the surface and strong built-in electrostatic field caused by wurtzite/zinc-blende structures. To tackle these issues, several effective approaches have been introduced, and the distinct progress has been achieved during the past decade. In this review, the simulation and prediction of properties of III-nitride nanosheets are outlined, and the corresponding solutions and novel developed techniques for realisation of III-nitride nanosheets and defect control are discussed in depth. Furthermore, the corresponding devices based on the as-grown III-nitride nanosheets are introduced accordingly. Moreover, perspectives toward the further development of III-nitrides nanosheets and devices are also discussed.
Urban NO
x
emissions around the world declined faster than anticipated between 2005 and 2019
Authors: Goldberg Daniel L , Anenberg Susan C , Lu Zifeng , Streets David G , Lamsal Lok N , E McDuffie Erin , Smith Steven J
Published: October 2021

Emission inventory development for air pollutants, by compiling records from individual emission sources, takes many years and involves extensive multi-national effort. A complementary method to estimate air pollution emissions is in the use of satellite remote sensing. In this study, NO2 observations from the Ozone Monitoring Instrument are combined with re-analysis meteorology to estimate urban nitrogen oxide (NO
X
) emissions for 80 global cities between 2005 and 2019. The global average downward trend in satellite-derived urban NOX emissions was 3.1%–4.0% yr−1 between 2009 and 2018 while inventories show a 0%–2.2% yr−1 drop over the same timeframe. This difference is primarily driven by discrepancies between satellite-derived urban NO
X
emissions and inventories in Africa, China, India, Latin America, and the Middle East. In North America, Europe, Korea, Japan, and Australasia, NOX emissions dropped similarly as reported in the inventories. In Europe, Korea, and Japan only, the temporal trends match the inventories well, but the satellite estimate is consistently larger over time. While many of the discrepancies between satellite-based and inventory emissions estimates represent real differences, some of the discrepancies might be related to the assumptions made to compare the satellite-based estimates with inventory estimates, such as the spatial disaggregation of emissions inventories. Our work identifies that the three largest uncertainties in the satellite estimate are the tropospheric column measurements, wind speed and direction, and spatial definition of each city.
Overview of the V International Conference on Agribusiness, Environmental Engineering and Biotechnologies – AGRITECH-V – 2021
Authors: Kovalev I V , Pyzhikova N I , Voroshilova A A , Shaporova Z E
Published: October 2021

The overview describes the main directions and results of the International Conference “AGRITECH-V-2021” held in Krasnoyarsk, Russia on 16-19 June 2021. It gives the details about the participants and the proceedings. The anchor partners of Krasnoyarsk Science and Technology City Hall were Krasnoyarsk State Agrarian University, the Volga Region Research Institute of Manufacture and Processing of Meat-and-Milk Production, Volgograd, Russia, Tashkent Institute of Irrigation and Agricultural Mechanization Engineers, Tashkent, Uzbekistan and Bukhara Engineering Technological Institute, Bukhara, Uzbekistan. The Krasnoyarsk Research Institute of Agriculture of the Federal Research Center “Krasnoyarsk Science Center of the Siberian Branch of the Russian Academy of Sciences” and Siberian Scientific Centre DNIT sponsored the Conference.