bluuebunny/crossref_metadata_2025 huggingface dataset:
Decomposing the dynamics of the Lorenz 1963 model using unstable periodic orbits: Averages, transitions, and quasi-invariant sets
Authors: Maiocchi Chiara Cecilia , Lucarini Valerio , Gritsun Andrey
Published: March 2022

Unstable periodic orbits (UPOs) are a valuable tool for studying chaotic dynamical systems, as they allow one to distill their dynamical structure. We consider here the Lorenz 1963 model with the classic parameters’ value. We investigate how a chaotic trajectory can be approximated using a complete set of UPOs up to symbolic dynamics’ period 14. At each instant, we rank the UPOs according to their proximity to the position of the orbit in the phase space. We study this process from two different perspectives. First, we find that longer period UPOs overwhelmingly provide the best local approximation to the trajectory. Second, we construct a finite-state Markov chain by studying the scattering of the orbit between the neighborhood of the various UPOs. Each UPO and its neighborhood are taken as a possible state of the system. Through the analysis of the subdominant eigenvectors of the corresponding stochastic matrix, we provide a different interpretation of the mixing processes occurring in the system by taking advantage of the concept of quasi-invariant sets.
Thermoelectric power generation via transverse thermo-spin conversions
Authors: Fujimoto Junji , Ogata Masao
Published: March 2022

We theoretically propose a mechanism of thermoelectric power generation via transverse thermo-spin conversions. We consider a material with strong spin–orbit coupling (the target material) and apply a temperature gradient to the target material, where the temperature gradient induces a transverse spin current. By attaching ferromagnets to the target material, we show the conversion of the nonequilibrium spin accumulation induced by the spin current into the electric voltage based on an extension of the Valet–Fert theory used in the giant magnetoresistive effect. A series circuit application is also discussed.
Spin–orbit torque controlled stochastic oscillators with synchronization and frequency tunability
Authors: Debashis Punyashloka , Maskay Aman K. , Upadhyaya Pramey , Chen Zhihong
Published: March 2022

Stochastic oscillators based on emerging nanodevices are attractive because of their ultra-low power requirement and the ability to exhibit stochastic resonance, a phenomenon where synchronization to weak input signals is enabled due to ambient noise. In this work, a low barrier nanomagnet-based stochastic oscillator is demonstrated, whose output jumps spontaneously between two states by harnessing the ambient thermal noise, requiring no additional power. By utilizing spin–orbit torque in a three-terminal device configuration, phase synchronization of these oscillators to weak periodic drives of particular frequencies is demonstrated. Experiments are performed to show the tunability of this synchronization frequency by controlling an electrical feedback parameter. The current required for synchronization is more than eight times smaller than that required for the deterministic switching of similar nanomagnetic devices. A model based on Kramers’ transition rate in a symmetric double well potential is adopted and dynamical simulations are performed to explain the experimental results.
Electron- and proton irradiation of strongly doped silicon of p-type: Formation and annealing of boron-related defects
Authors: Emtsev Vadim , Abrosimov Nikolay , Kozlovski Vitalii , Lastovskii Stanislav , Oganesyan Gagik , Poloskin Dmitrii
Published: March 2022

A detailed study of boron-related defects in strongly doped p-type silicon subjected to irradiation with 3.5 MeV electrons and 15 MeV protons are carried out by means of electrical measurements over a wide temperature range of 25 ≤ T ≤ 300 K. Investigations are aimed at taking a close look into the nature of radiation-produced defects that are stable at room temperature. Data obtained allow one to reveal two types of dominant boron-related complexes, which are attributed to the substitutional boron-interstitial boron pair being neutral in p-type Si and the substitutional boron-divacancy complex displaying donor activity. The first type of the defects is very stable and its annealing runs in a temperature region of 500–700 °C. Another type of defect turned out to be stable up to 300 °C. The formation and annealing processes of the boron-related defects appear to be very similar for electron and proton irradiation of p-type Si.
Thermal annealing of GaN implanted with Be
Authors: Reshchikov M. A. , Andrieiev O. , Vorobiov M. , Ye D. , Demchenko D. O. , Sierakowski K. , Bockowski M. , McEwen B. , Meyers V. , Shahedipour-Sandvik F.
Published: March 2022

GaN samples were implanted with Be and annealed in different conditions in order to activate the shallow BeGa acceptor. Low-temperature photoluminescence spectra were studied to find BeGa-related defects in the implanted samples. A yellow band with a maximum at about 2.2 eV (the YLBe band) was observed in nearly all samples protected with an AlN cap during the annealing and in samples annealed under ultrahigh N2 pressure. A green band with a maximum at 2.35 eV (the GL2 band), attributed to the nitrogen vacancy, was the dominant defect-related luminescence band in GaN samples annealed without a protective AlN layer. The ultraviolet luminescence (UVLBe) band with a maximum at 3.38 eV attributed to the shallow BeGa acceptor with the ionization energy of 0.113 eV appeared in implanted samples only after annealing at high temperatures and ultrahigh N2 pressure. This is the first observation of the UVLBe band in Be-implanted GaN, indicating successful activation of the BeGa acceptor.
Shock Hugoniot of porous nanosized nickel
Authors: Dolgoborodov A. Yu. , Ananev S. Yu. , Yakushev V. V. , Rostilov T. A. , Ziborov V. S. , Kuskov M. L. , Zhigach A. N. , Kirilenko V. G. , Pirog V. A. , Grishin L. I. , Valyano G. E.
Published: March 2022

The shock compression of porous nickel from nanosized particles nNi was studied at a pressure range of 4–61 GPa. The average size of the nNi particles was 50 nm, and the porosity of the samples was 50%. Plane shock waves in the samples were generated by the impact of aluminum plates accelerated to velocities ranging from 0.8 to 5 km/s. Laser interferometry was used to monitor particle velocity histories at the interface between the samples and water or LiF windows. The data obtained at pressures below 8 GPa showed a complex shock wave profile with the formation of an elastic precursor wave. The shock Hugoniot and data on the expansion isentropes were obtained. The Hugoniot of nanosized nNi coincided within the experimental errors with the Hugoniot of micron-sized nickel. The Hugoniot calculated on the basis of the equation of state for porous nickel was in good agreement with that of experimental data. It has been established that in the middle pressure range (20–35 GPa), the expansion isentropes in the “pressure–particle velocity” coordinates become noticeably flatter with a significant increase in the particle velocity. The reason for this phenomenon is still unclear. An assumption was made about the onset of particle melting upon reaching pressures above 15 GPa.
Comparison of the hydrodynamic performance of front and rear-stator pump-jet propulsors in an oblique wake under the cavitation condition
Authors: Sun Yu , Peng Huanghua , Liu Wei , Guo Jiamin , Guo Ya
Published: March 2022

Pump-jet propulsors, which exhibit high efficiency and low noise, are widely used in underwater vehicles. In a marine environment, a nonuniform wake and an oblique flow affect a propulsor's hydrodynamic force. Therefore, the hydrodynamic performance of front and rear-stator pump-jet propulsors under complex operational conditions was compared in this study. The unsteady hydrodynamic performance was predicted using a shear stress transport k–ω model. When the calculation converged, the Schnerr–Sauer cavitation model was used to simulate the cavitation performance. After an analysis of grid independence and a verification of the calculation model's reliability, the hydrodynamic performance of two pump-jet propulsors in an oblique wake was simulated under the non-cavitation and cavitation conditions. The results indicate that under the non-cavitation condition, the performance of the front-stator pump-jet propulsor worsens more slowly with an increase in the inflow angle. Moreover, the rear-stator pump-jet propulsor stops exhibiting high efficiency when the flow angle (β) is 30°. When cavitation occurs, the performance of the two pump-jet propulsors worsens and their hydrodynamic coefficients decrease rapidly. When β = 30°, the front and rear-stator pump-jet propulsors lose 60% and 40% of their thrust, respectively. The results of this study indicate that cavitation generation has a greater impact on the performance of a front-stator pump-jet propulsor.
Rapid scan ESR: A versatile tool for the spin relaxation studies at (sub)THz frequencies
Authors: Laguta O. , Sojka A. , Marko A. , Neugebauer P.
Published: March 2022

The development of pulse electron spin resonance (ESR) spectroscopy at microwave frequencies above 100 GHz is rather challenging and expensive due to the low output power of modern high-frequency solid state electronics. However, there is a number of scientific problems that require spin relaxation measurements at THz frequencies. The rapid scan ESR is an alternative technique that does not require high microwave power and still provides information on the spin relaxation times. The method takes advantage of fast sweeps of the excitation microwave frequency over the ESR line. When the frequency sweep reaches a sufficiently high rate, distinct oscillations (also called wiggles) appear in the ESR spectrum. These oscillations bear information about T2 electron spin relaxation time, which can be extracted via fitting the rapid scan spectrum using the modified Bloch equations. In this Perspective Letter, we introduce the recent advances in this technique and discuss the future steps necessary to make the THz rapid scan ESR a convenient and easy to use tool.
Design, analysis, and testing of Petrel acoustic autonomous underwater vehicle for marine monitoring
Authors: Wang Xuehao , Wang Yanhui , Wang Peng , Yang Shaoqiong , Niu Wendong , Yang Yehao
Published: March 2022

Autonomous underwater vehicles (AUVs) provide a unique and cost-effective platform for conducting ocean acoustic measurements and surveys such as marine mammal monitoring, extensive area seafloor topography survey, and fish stock survey. The small and medium-sized AUVs combine load-carrying capability, motion, and range and allow for timescale observations that are difficult to achieve with traditional acoustic observation platforms. However, self-noise is still an unavoidable challenge for AUVs when applied in passive acoustic monitoring. This paper presents the acoustic observation application of the Petrel acoustic AUV in marine monitoring. The layout design of a Petrel acoustic AUV and acoustic sensor integration are described in detail, and the self-noise characteristics of Petrel acoustic AUVs are evaluated by simulation and testing. The results showed that the self-noise level of Petrel acoustic AUVs is effectively controlled with its optimized design, and the maximum noise of the propulsion system is only 75 dB in the low-frequency band. Therefore, the Petrel acoustic AUV can be used as an ideal acoustic observation platform to carry out diverse observation tasks. Finally, a solution of fixed-depth motion is proposed to address the problem that frequent attitude adjustment affects the quality of acoustic data in fixed-depth navigation. According to a sea trial in the South China Sea, the method can significantly reduce the attitude adjustment frequency and, thus, provide an ideal environment for acoustic observation. This method also applies to other underwater mobile observation platforms. This study provides a reference for the acoustic integration design of underwater equipment such as long-range AUVs or hybrid-driven underwater gliders.
Numerical investigation on the role of a mixer on spray impingement and mixing in channel cross-stream airflow
Authors: Venkatachalam Palaniappan , Sahu Srikrishna , Anupindi Kameswararao
Published: March 2022

The present study numerically investigates the influence of introducing a spin-type mixer and different angular orientations of the mixer blades on the spray-wall interaction and mixing, following cross-stream injection of a pulsed spray into airflow in a circular duct. This is relevant to the Selective Catalytic Reduction system in diesel engines for exhaust gas after-treatment. The spin-type static mixer is located downstream of the injector and generates a swirling airflow in the duct. All simulations were carried out using ANSYS Fluent V18.0. The standard k–ω model is used to simulate the turbulent continuous phase flow, while the discrete phase model is employed to track the spray droplets. The Taylor Analogy Breakup and Kuhnke wall film models are adopted to model droplet breakup and wall-film formation, respectively. First, the swirling airflow characteristics without spray injection are validated against in-house particle image velocimetry measurements. Second, the spray computations are compared with the experiment. Overall, good agreement between simulation and experiment is achieved. Furthermore, the choice of water and urea water solution injection liquid on the in-channel spray characteristics is also studied. The main focus of the present work is on the study of the influence of spin mixer clocking on the post-impingement spray evolution, droplet redistribution and mixing, and wall-film characteristics. The results show that the choice of the angular orientation of the mixer governs the extent of droplet deposition and splashing on the mixer blades and, as a result, strongly influences the spatial uniformity of droplets and ammonia species at the channel exit.
Redshifted biexciton and trion lines in strongly confined (211)B InAs/GaAs piezoelectric quantum dots
Authors: Chatzarakis N. G. , Amargianitakis E. A. , Germanis S. , Stavrinidis A. , Konstantinidis G. , Hatzopoulos Z. , Pelekanos N. T.
Published: March 2022

The emission lines of strongly confined (211)B InAs/GaAs quantum dots (QDs), embedded in short-period GaAs/AlAs superlattices, are thoroughly characterized by a range of single-dot spectroscopy techniques, including cross correlation photon-counting measurements. Contrary to what is expected for a piezoelectric QD system, the single-dot biexciton line is found redshifted with respect to the exciton one by as many as 6 meV. This comes in striking contrast to previous reports on the same QD system, without additional confinement, where the biexciton lines always showed up at higher energies than the exciton, by 4–13 meV. In addition, two charged exciton lines are identified for the first time in a piezoelectric InAs-based QD. A positively charged (Χ+) and a negatively charged (Χ−) trion line are observed 1.5 and 7.5 meV below the neutral exciton line, respectively. Our results pave the way to an enhanced understanding of the excitonic transitions in (211)B QDs and highlight the possible role of strong confinement and accompanying correlation effects as a means to tailor the transition energies of multi-particle states in semiconductor QDs.
Stability analysis for laminar separation flutter of an airfoil in the transitional flow regime
Authors: Yu Qiuyang , Li Xintao , Zhang Weiwei , Xu Shengjin
Published: March 2022

Laminar separation flutter (LSF) is a type of aeroelastic instability phenomenon characterized by small-amplitude low-frequency pitching oscillations of the airfoil. The present study aims to gain insight into the intrinsic dynamics of LSF via data-driven stability analysis. The proposed data-driven approach relies on the autoregressive with exogenous input (ARX) technique to design reduced-order models (ROMs) of unsteady aerodynamics in a state-space format. First, high-fidelity full-order numerical simulations of the LSF phenomenon are performed using the incompressible Unsteady Reynolds-Averaged Navier–Stokes equations and the Shear-Stress Transport k−ω  turbulence model with Low-Reynolds-number correction. The calculated LSF responses show good agreement with previous experimental data in the literature. Then, linear stability analysis (LSA) of the aeroelastic system is carried out to reveal the underlying fluid-structure interaction mechanism. The LSA model is developed by coupling the ROM with the structure motion equation. LSA results indicate that the LSF phenomenon is primarily caused by the instability of the structure mode (SM), which is induced by the mutual repulsion effect between one static fluid mode (FM) and the SM. The presence of laminar separation near the trailing-edge of the airfoil can significantly reduce the stability of the static FM, which ultimately strengthens the fluid-structure coupling effect and leads to LSF. We would like to emphasize that LSF is essentially different from other flow-induced vibration phenomena, such as transonic buffeting of an airfoil and vortex-induced vibration of bluff bodies, for which the instabilities are triggered by the coupling between one dynamic FM and the SM. Finally, the effects of the mass ratio, structural damping ratio, and freestream turbulence intensity on the aeroelastic system are also investigated.
Line-shaped defects: Origin of leakage current in halide vapor-phase epitaxial (001)
β
-Ga2O3 Schottky barrier diodes
Authors: Sdoeung Sayleap , Sasaki Kohei , Kawasaki Katsumi , Hirabayashi Jun , Kuramata Akito , Oishi Toshiyuki , Kasu Makoto
Published: March 2022

We observed line-shaped defects in halide vapor-phase epitaxial (001) β-Ga2O3 SBDs. Light emission patterns, representing the reverse leakage current, were observed at these line-shaped defects. In atomic force microscopy observations, the line-shaped defects appeared as grooves with a typical depth and width of 113 and 520 nm, respectively. Such defects corresponded to a leakage current of −0.23 μA at −200 V. Simulation results indicated that the electric field, with an intensity of 1.3 MV/cm, was highly concentrated at the bottom of the line defects. According to the cross-sectional scanning transmission electron microscopy analysis, the line-shaped defects were generated from a dislocation network beneath the crystal near the surface.
First-order phase transition in a two dimensional BM3 model
Authors: Sellitto Mauro
Published: March 2022

The phase behavior of a Biroli–Mézard model on the two dimensional square lattice in which hard-core particles can have at most three nearest neighboring occupied sites is investigated by means of grand-canonical Monte Carlo simulations. Finite-size scaling analysis of relevant thermodynamic quantities obtained via the histogram reweighting technique reveals that at high-density, the model undergoes a first-order phase transition with preferential sublattice occupation to a crystal phase with enantiomorph ground state configurations, in close analogy to the hard-core lattice gas with the exclusion range extended up to the third shell of nearest neighbors.
A single-shot vaccine approach for the universal influenza A vaccine candidate M2e
Authors: Kavishna Ranmali , Kang Tha Yang , Vacca Maurizio , Chua Benson Yen Leong , Park Hae-Young , Tan Peck Szee , Chow Vincent TK , Lahoud Mireille H , Alonso Sylvie
Published: March 2022

Significance

Although the need for a universal influenza vaccine has long been recognized, only a handful of candidates have been identified so far, with even fewer advancing in the clinical pipeline. The 24–amino acid ectodomain of M2 protein (M2e) has been developed over the past two decades. However, M2e-based vaccine candidates have shortcomings, including the need for several administrations and the lack of sustained antibody titers over time. We report here a vaccine targeting strategy that has the potential to confer sustained and strong protection upon a single shot of a small amount of M2e antigen. The current COVID-19 pandemic has highlighted the importance of developing versatile, powerful platforms for the rapid deployment of vaccines against any incoming threat.
The virota and its transkingdom interactions in the healthy infant gut
Authors: Beller Leen , Deboutte Ward , Vieira-Silva Sara , Falony Gwen , Tito Raul Yhossef , Rymenans Leen , Yinda Claude Kwe , Vanmechelen Bert , Van Espen Lore , Jansen Daan , Shi Chenyan , Zeller Mark , Maes Piet , Faust Karoline , Van Ranst Marc , Raes Jeroen , Matthijnssens Jelle
Published: March 2022

Significance

Microbes colonizing the infant gut during the first year(s) of life play an important role in immune system development. We show that after birth the (nearly) sterile gut is rapidly colonized by bacteria and their viruses (phages), which often show a strong cooccurrence. Most viruses infecting the infant do not cause clinical signs and their numbers strongly increase after day-care entrance. The infant diet is clearly reflected by identification of plant-infecting viruses, whereas fungi and parasites are not part of a stable gut microbiota. These temporal high-resolution baseline data about the gut colonization process will be valuable for further investigations of pathogenic viruses, dynamics between phages and their bacterial host, as well as studies investigating infants with a disturbed microbiota.
Likelihood-based non-Markovian models from molecular dynamics
Authors: Vroylandt Hadrien , Goudenège Ludovic , Monmarché Pierre , Pietrucci Fabio , Rotenberg Benjamin
Published: March 2022

Significance

The analysis of complex systems with many degrees of freedom generally involves the definition of low-dimensional collective variables more amenable to physical understanding. Their dynamics can be modeled by generalized Langevin equations, whose coefficients have to be estimated from simulations of the initial high-dimensional system. These equations feature a memory kernel describing the mutual influence of the low-dimensional variables and their environment. We introduce and implement an approach where the generalized Langevin equation is designed to maximize the statistical likelihood of the observed data. This provides an efficient way to generate reduced models to study dynamical properties of complex processes such as chemical reactions in solution, conformational changes in biomolecules, or phase transitions in condensed matter systems.
KCNQ2 and KCNQ5 form heteromeric channels independent of KCNQ3
Authors: Soh Heun , Springer Kristen , Doci Klarita , Balsbaugh Jeremy L. , Tzingounis Anastasios V.
Published: March 2022

Significance

There are five KCNQ channels (KCNQ1–KCNQ5) and they are thought to either homomerize or heteromerize to form tetrameric channels. KCNQ2 and KCNQ3 are highly expressed in the brain and in particular the forebrain, the presumed site of action for many brain disorders. For the last 30 years, the prevailing view is that KCNQ potassium channels in the brain consist of KCNQ2/3 and possibly KCNQ3/5 heteromers. Here, using epitope-tagged knockin mice and split-intein–mediated protein trans-splicing experiments, we demonstrate that KCNQ2 channels form heteromers not only with KCNQ3 but also with KCNQ5 channels. Thus, our findings of unexpected KCNQ subunit composition will shift both our understanding of KCNQ genotype/phenotype relationships as well as drug screening strategies.
Spin-triplet superconductivity from excitonic effect in doped insulators
Authors: Crépel Valentin , Fu Liang
Published: March 2022

Significance

We present a mechanism for unconventional superconductivity in doped band insulators, where short-ranged pairing interaction arises from Coulomb repulsion due to virtual interband or excitonic processes. Remarkably, electron pairing is found upon infinitesimal doping, giving rise to Bose–Einstein condensate (BEC)–Bardeen–Cooper–Schrieffer (BCS) crossover at low density. Our theory explains puzzling behaviors of superconductivity and predicts spin-triplet pairing in electron-doped ZrNCl and WTe
2
.
Context matters
Authors: Hänsel Eva Canan , Westphal Michael , Meer Philipp , Deuber Dagmar
Published: March 2022

This paper presents the results of two largely parallel verbal guise studies that elicited students’ attitudes
toward different standard varieties of English. The studies were conducted in the small anglophone Caribbean island country of
Grenada. The two studies were contextualized in the domains of education and newscasting, respectively, with the aim of finding
out how language attitudes are influenced by context in societies where different endo- and exonormative standards are of
relevance. As hypothesized, the results revealed strong differences between the evaluations of speakers of the two domains and
confirm that contextualization is crucial in language attitude research. Against previous hypotheses, however, the acceptance of
endonormative standard accents was stronger in the more globally open context of newscasting than in the more locally restricted
domain of education. The results are discussed against the background of the sociolinguistic situation in Grenada and inform on
endonormativity and norm orientation in one of the underresearched island countries of the anglophone Caribbean.
Zamboanga Chavacano
Authors: Melchor Jillian Loise , Blázquez-Carretero Miguel
Published: March 2022

Existing literature on Philippine languages is rife with references to Chavacano, the hypernym for Spanish-based
creoles spoken in various parts of the archipelago. Variants of Chavacano are characterised in historical accounts as ‘a corrupt
Spanish dialect’ with depreciative labels such as español de tienda ‘hawker Spanish’ or español de
cocina ‘kitchen Spanish’. The concerted assertion of this creole’s degeneracy is a legacy of colonial knowledge
production. Since the genesis of the Philippine creoles, much has changed as to their usage both from a linguistic and a social
viewpoint. It is in this social dimension that we locate the present study. Of the three main varieties of Chavacano, spoken in
Cavite City, Ternate, and Zamboanga respectively, this paper zeroes in on the third as the Mindanaoan variety is the healthiest to
date. We wish to interrogate the trajectory of its social status, from its characterisation as a degenerate variant of Spanish to
its privileged position in contemporary Zamboanga City as a Hispanic identity marker (Chavacano un poquito
español ‘Chavacano slightly Spanish’). Nuancing the role played in language preservation efforts by Zamboangueño
elites, this study highlights the singularity of a creolophone community, who, through the politicisation of heritage, has
subverted the ideological marginality of their Creole mother tongue and appropriated it to be the hallmark of their ethnic
identity.
Dauphin, sirène, coq basilic, vent marin
Authors: Colombo Timelli Maria
Published: March 2022

Le Dialogus creaturarum, recueil de 122 fables compilé au XIVe siècle par un auteur anonyme, a joui d’un succès européen, manuscrit et imprimé, qui s’est prolongé jusque vers 1550; trois versions françaises en sont connues: les deux premières en prose, l’une de Colard Mansion (1482), l’autre anonyme (1482 également), la plus tardive, manuscrite et en vers, de Jean Gontier (ca 1539–1549).

Les créatures de Dieu, protagonistes de ces récits, y interviennent selon l’ordre de la Genèse: la section consacrée aux poissons, la quatrième, comprenant les dialogues 37 à 48. L’intérêt du recueil ne réside pourtant pas dans ce qu’il nous dit sur les poissons (il ne fait que confirmer le caractère non homogène de la catégorie, qui indique au Moyen Âge un groupe malaisé à appréhender, piscis étant tout animal / être vivant qui vit dans l’eau), ni dans le contenu des enseignements impartis (conseils de prudence; mises en garde contre les femmes ou les vices: avarice, hypocrisie, superbe, colère, ingratitude; les fables sur les poissons ne se distinguant pas des autres), ni encore dans les descriptions fournies, mais justement dans la présence même de ces êtres dans un recueil de fables. L’analyse proposée ici prend en compte tant les aspects lexicographiques et textuels que l’iconographie, qui concourt, dans l’ensemble de la tradition, à l’approche et à la compréhension du recueil.
Connecting people and voices for radical change in Africa
Authors: Zeilig Leo
Published: March 2022

In this section of the journal, we aim to give readers of the print journal a picture of what has been published on Roape.net over the last few months, and invite you to connect and follow the articles, blogposts, authors and debates online. Details of all the blogposts referred to here are in the reference list at the end. We warmly invite all our readers to sign up to the Roape.net newsletter by entering their email address at the top of the home page of the website.
Audiometric notch as a sign of noise induced hearing loss (NIHL) among the rice and market flour mill workers in Tamil Nadu, South India
Authors: Narasimhan Sharanya , Rajagopalan Ramakrishnan , Justin Margret Jeffrey , Visvanathan Gnanaprakash , Jayasankaran Chandru , Rekha Kota , Srisailapathy C. R. Srikumari
Published: March 2022

Objective

This study aims to determine the prevalence of NIHL among rice and flour mill workers exposed to high decibel noise levels at the workplace.

Methods

One-hundred and seven workers exposed to noise from rice and flour mill machinery and 82 age-matched controls not exposed to noise at the workplace were recruited for the study from the south Indian state of Tamil Nadu. All the mill workers and the controls were evaluated for their hearing thresholds by pure-tone audiometry.

Results

The characteristic bilateral notch in 4000 Hz was detected in 25% of the mill workers, while the prevalence of the unilateral or bilateral notch was observed in 51%. The high-frequency slope (HFS) involving HL at 4000 and 8000 Hz was observed in 23.36 and 29.92% among the left and right ears of the mill workers, respectively. Years of experience and exposure to noise were strongly associated with a bilateral notch in 4000 Hz (the odds of having the notch increased with increased years of noise exposure). Self-reported HL under-represented the rates of actual HL, indicating perception of the HL was absent till audiometric evaluation revealed the loss.

Conclusion

Our study demonstrates exposure to high noise levels in this unorganized sector of rice and flour mill workers. Awareness education of NIHL, early detection, and the use of personal hearing protection devices can prevent HL from extending to speech frequencies.
Local regulation of extracellular vesicle traffic by the synaptic endocytic machinery
Authors: Blanchette Cassandra R. , Scalera Amy L. , Harris Kathryn P. , Zhao Zechuan , Dresselhaus Erica C. , Koles Kate , Yeh Anna , Apiki Julia K. , Stewart Bryan A. , Rodal Avital A.
Published: March 2022

Neuronal extracellular vesicles (EVs) are locally released from presynaptic terminals, carrying cargoes critical for intercellular signaling and disease. EVs are derived from endosomes, but it is unknown how these cargoes are directed to the EV pathway rather than for conventional endolysosomal degradation. Here, we find that endocytic machinery plays an unexpected role in maintaining a release-competent pool of EV cargoes at synapses. Endocytic mutants, including nervous wreck (nwk), shibire/dynamin, and AP-2, unexpectedly exhibit local presynaptic depletion specifically of EV cargoes. Accordingly, nwk mutants phenocopy synaptic plasticity defects associated with loss of the EV cargo synaptotagmin-4 (Syt4) and suppress lethality upon overexpression of the EV cargo amyloid precursor protein (APP). These EV defects are genetically separable from canonical endocytic functions in synaptic vesicle recycling and synaptic growth. Endocytic machinery opposes the endosomal retromer complex to regulate EV cargo levels and acts upstream of synaptic cargo removal by retrograde axonal transport. Our data suggest a novel molecular mechanism that locally promotes cargo loading into synaptic EVs.
Tweaking neural organoids to model human reactive astrocytes
Authors: Bezzi Paola
Published: March 2022

The study of human reactive astrocytes has been limited by resource availability. In this issue, Cvetkovic et al. (2022. J. Cell Biol.https://doi.org/10.1083/jcb.202107135) develop multicellular organoid systems containing mature astrocytes to study the dynamics of human astrocytes reactivity and its downstream effects on neuronal activity.
Coupling of angiogenesis and odontogenesis orchestrates tooth mineralization in mice
Authors: Matsubara Tomoko , Iga Takahito , Sugiura Yuki , Kusumoto Dai , Sanosaka Tsukasa , Tai-Nagara Ikue , Takeda Norihiko , Fong Guo-Hua , Ito Kosei , Ema Masatsugu , Okano Hideyuki , Kohyama Jun , Suematsu Makoto , Kubota Yoshiaki
Published: March 2022

The skeletal system consists of bones and teeth, both of which are hardened via mineralization to support daily physical activity and mastication. The precise mechanism for this process, especially how blood vessels contribute to tissue mineralization, remains incompletely understood. Here, we established an imaging technique to visualize the 3D structure of the tooth vasculature at a single-cell level. Using this technique combined with single-cell RNA sequencing, we identified a unique endothelial subtype specialized to dentinogenesis, a process of tooth mineralization, termed periodontal tip-like endothelial cells. These capillaries exhibit high angiogenic activity and plasticity under the control of odontoblasts; in turn, the capillaries trigger odontoblast maturation. Metabolomic analysis demonstrated that the capillaries perform the phosphate delivery required for dentinogenesis. Taken together, our data identified the fundamental cell-to-cell communications that orchestrate tooth formation, angiogenic–odontogenic coupling, a distinct mechanism compared to the angiogenic–osteogenic coupling in bones. This mechanism contributes to our understanding concerning the functional diversity of organotypic vasculature.
The full quadratic metric-affine gravity (including parity odd terms): exact solutions for the affine-connection
Authors: Iosifidis Damianos
Published: March 2022

We consider the most general quadratic metric-affine gravity setup in the presence of generic matter sources with non-vanishing hypermomentum. The gravitational action consists of all 17 quadratic invariants (both parity even and odd) in torsion and non-metricity as well as their mixings, along with the terms that are linear in the curvature namely the Ricci scalar and the totally antisymmetric Riemann piece. Adding also a matter sector to the latter we first obtain the field equations for the generalized quadratic theory. Then, using a recent theorem, we successfully find the exact form of the affine connection under some quite general non-degeneracy conditions. Having obtained the exact and unique solution of the affine connection we subsequently derive the closed forms of spacetime torsion and non-metricity and also recast the metric field equations into a GR form with modified source terms that are quadratic in the hypermomentum and linear in its derivatives. We also study the vacuum quadratic theory and prove that in this instance, or more generally for vanishing hypermomentum, the connection becomes the Levi-Civita one. Therefore, we also find exactly to what does the quadratic vacuum theory correspond to. Finally, we generalize our result even further and also discuss the physical consequences and applications of our study.
Permeability estimation of a porous structure in cancer treatment based on sampled velocity measurement*
Authors: Afshar Sepideh , Hu Weiwei
Published: March 2022

The problem of parameter identification appears in many physical applications. A parameter of particular interest in cancer treatment is permeability, which modulates the fluidic streamlines in the tumor microenvironment. Most of the existing permeability identification techniques are invasive and not feasible to identify the permeability with minimal interference with the porous structure in their working conditions. In this paper, a theoretical framework utilizing partial differential equation (PDE)-constrained optimization strategies is established to identify a spatially distributed permeability of a porous structure from its modulated external velocity field measured around the structure. In particular, the flow around and through the porous media are governed by the steady-state Navier–Stokes–Darcy model. The performance of our approach is validated via numerical and experimental tests for the permeability of a 3D printed porous surrogate in a micro-fluidic chip based on the sampled optical velocity measurement. Both numerical and experimental results show a high precision of the permeability estimation.
Germination and growth improvement of papaya utilizing oxygen (O2) plasma treatment
Authors: Ahmed Naeem , Shahid Muhammad , Siow Kim S , Razip Wee M F Mohd , Haron Farah Farhanah , Patra Anuttam , Fazry Shazrul
Published: March 2022

In general, cold plasma treatment improves crop germination and growth. The purpose of this research is to examine the impact of low-pressure O2 plasma treatment on the germination and growth kinetics of papaya seeds. Seeds were treated for 40 s at a discharge power of 80 W using O2 as a monomer. Physical and chemical changes were studied to understand the mechanism of germination and growth improvement. Furthermore, changes in phytohormones and antioxidant activity that were beneficial to germination were also examined. O2 plasma treatment improved wettability, surface etching, and oxidation, and affected other molecular-level changes leading to a 16% germination improvement in papaya.
Theoretical and experimental study on a new reconstruction model based on geometric optics for a single-lens biprism-based stereovision system
Authors: Wang Mu
Published: March 2022

In the present work, we report a stereovision system with one single camera. The configuration has only one single camera in front of which a biprism is placed. A new mathematical model based on optical geometrical optics is proposed for a single-lens biprism-based (SLBB) stereovision system in this paper. The path of each ray in three-dimensional (3D) space is tracked precisely, and the intersection of the rays is determined by an optimization method. Under the assumption of pinhole imaging, the 3D coordinate of the measuring point can be obtained through this model. Further, the model has been examined and verified by experiment. The experimental results show that the mathematical model can effectively measure the depth of the measuring points and the relative distance between measuring points. The deviation between the reconstruction results of the measuring point and the real 3D coordinate shows a certain regularity with the changing of the distance between the measuring point and the camera.
Near-infrared imaging of water vapour in air
Authors: Kakuta Naoto , Ozawa Shintaro
Published: March 2022

This study proposes a near-infrared (NIR) imaging method for two-dimensional distributions of water vapour (WV) in the open air. A wavelength of 1872 nm, at which the dependence of the absorption coefficient on the WV concentration is the largest in the v
2 + v
3 band of water molecules, was employed for imaging. The measurement system was a star imaging system, comprising a laser light source and an NIR camera. A measurement space with 0.08 m diameter and 0.30 m length was ensured to obtain the 2D absorbance images of moist air emitted from a gas nozzle and the breath air exhaled from a human subject with and without a mask. The images clearly showed the distributions of WV that flowed around a pipe and impinged on a plate. The exhaled air was clearly visualised, and the difference in air permeability between the masks was demonstrated. These results indicate the potential of the NIR imaging method for various applications that require WV flow visualisation, WV source identification, and evaporation process observation.
Effect of extreme mechanical densification on the electrical properties of carbon nanotube micro-yarns
Authors: Miralaei Cassandre , Le Floch Sylvie , Debord Regis , Nguyen Hung V , Da Silva Julio C , San-Miguel Alfonso , Le Poche Hélène , Pailhès Stephane , Pischedda Vittoria
Published: March 2022

We have explored the effect of high pressure post-treatment in optimizing the properties of carbon nanotube yarns and found that the application of dry hydrostatic pressure reduces porosity and enhances electrical properties. The CNT yarns were prepared by the dry-spinning method directly from CNT arrays made by the hot filament chemical vapour deposition (HF-CVD) process. Mechanical hydrostatic pressure up to 360 MPa induces a decrease in yarn resistivity between 3% and 35%, associated with the sample’s permanent densification, with CNT yarn diameter reduction of 10%–25%. However, when increasing the pressure in the 1–3 GPa domain in non-hydrostatic conditions, the recovered samples show lower electrical conductivity. This might be due to concomitant macroscopic effects such as increased twists and damage to the yarn shown by SEM imaging (caused by strong shear stresses and friction) or by the collapse of the CNTs indicated by in situ high pressure Raman spectroscopy data.
Effects of off-axis translocation through nanopores on the determination of shape and volume estimates for individual particles
Authors: Ying Cuifeng , Houghtaling Jared , Mayer Michael
Published: March 2022

Resistive pulses generated by nanoparticles that translocate through a nanopore contain multi-parametric information about the physical properties of those particles. For example, non-spherical particles sample several different orientations during translocation, producing fluctuations in blockade current that relate to their shape. Due to the heterogenous distribution of electric field from the center to the wall of a nanopore while a particle travels through the pore, its radial position influences the blockade current, thereby affecting the quantification of parameters related to the particle’s characteristics. Here, we investigate the influence of these off-axis effects on parameters estimated by performing finite element simulations of dielectric particles transiting a cylindrical nanopore. We varied the size, ellipsoidal shape, and radial position of individual particles, as well as the size of the nanopore. As expected, nanoparticles translocating near the nanopore wall produce increase current blockades, resulting in overestimates of particle volume. We demonstrated that off-axis effects also influence estimates of shape determined from resistive pulse analyses, sometimes producing a multiple-fold deviation in ellipsoidal length-to-diameter ratio between estimates and reference values. By using a nanopore with the minimum possible diameter that still allows the particle to rotate while translocating, off-axis effects on the determination of both volume and shape can be minimized. In addition, tethering the nanoparticles to a fluid coating on the nanopore wall makes it possible to determine an accurate particle shape with an overestimated volume. This work provides a framework to select optimal ratios of nanopore to nanoparticle size for experiments targeting free translocations.
Automatic sleep staging of EEG signals: recent development, challenges, and future directions
Authors: Phan Huy , Mikkelsen Kaare
Published: March 2022

Modern deep learning holds a great potential to transform clinical studies of human sleep. Teaching a machine to carry out routine tasks would be a tremendous reduction in workload for clinicians. Sleep staging, a fundamental step in sleep practice, is a suitable task for this and will be the focus in this article. Recently, automatic sleep-staging systems have been trained to mimic manual scoring, leading to similar performance to human sleep experts, at least on scoring of healthy subjects. Despite tremendous progress, we have not seen automatic sleep scoring adopted widely in clinical environments. This review aims to provide the shared view of the authors on the most recent state-of-the-art developments in automatic sleep staging, the challenges that still need to be addressed, and the future directions needed for automatic sleep scoring to achieve clinical value.
MARFE movement and density fluctuations after deuterium pellet injections in H-mode plasmas on EAST tokamak
Authors: Hou Jilei , Chen Yue , Zuo Guizhong , Hu Jiansheng , Mao Songtao , Yuan Xiaolin , Huang Jia , Wu Mingfu , Xu Liqing , Zhao Hailin , Yuan Jingsheng , Wang Shouxin , Liu Haiqing , Meng Lingyi , Shi Tonghui , Li Pan , Li Jiangang
Published: March 2022

The multifaceted asymmetric radiation from the edge (MARFE), which is generally considered to be the result of a radiation thermal instability in the edge and usually occurs in high density operation, has been first observed to move up and down along the poloidal cross-section due to edge cooling after cryogenic deuterium pellet injections in EAST tokamak with tungsten divertor. A maximum electron density of 0.84 × n
GW has been obtained using continuous cryogenic pellet fueling. In the meantime, MARFEs, initially located near the divertors of EAST, moves to the inner wall on high field side after each pellet injection. This movement should be attributed to the asymmetry of the power flow to the two sides of the MARFE after pellet injections. Accompanied with MARFE movement, two kinds of strong density fluctuations have been observed. The ones with continuous and regular frequency spectrum, which does not cause a reduction of main plasma density, are confirmed to be induced by MARFE. The others, appearing with magnetic fluctuations, have been determined to be induced by the m/n = 2/1 magnetohydrodynamic activities after pellet injections. All the investigations in this paper will be meaningful for the steady high density operation of future fusion reactors, such as ITER.
Novel CMOS-based multi-band terahertz detector for passive imaging
Authors: Zhang Yongfeng , Zhang Shufang
Published: March 2022

The existing terahertz detectors based on complementary metal oxide semiconductor cannot meet the design requirements of passive terahertz focal plane imaging chips owing to the problems of excessive noise or high-power consumption. To overcome this limitation, this study innovatively proposes using the gate of an N-type metal oxide semiconductor (NMOS) as a matching impedance of a multi-band terahertz on-chip antenna. In this way, the conversion of incident radiation into heat is achieved, and it is concentrated above the NMOS channel. The temperature characteristics of the equivalent impedance of the NMOS in the cutoff region are used to measure the incident radiated power without the DC bias current. The principle and simulation results of the proposed detector are given by system modeling, multi-band terahertz on-chip antenna design, and detector design. The experimental results show that the noise equivalent power of the proposed detector is very close to 1

pW

Hz

−
1

under liquid nitrogen cooling, which can meet the design requirements of passive terahertz focal plane imaging chips.