bluuebunny/crossref_metadata_2025 huggingface dataset:
An Initial Investigation Into the Feasibility of the Communication Matrix Professional Development Program for Educational Professionals Working With Students With Complex Communication Needs
Authors: Quinn Emily D. , Cook Alexandria , Wiedrick Jack , Rowland Charity
Published: October 2021

Purpose

The goal of this study was to investigate the initial feasibility of the Communication Matrix Professional Development Program (CMPDP), an online program created to help educational professionals teaching students with complex communication needs.

Method

A one-group pretest–posttest design was employed with 102 educational professionals and their students with complex communication needs. Students (
M
age
= 12.5 years,
SD
= 4.8 years) had severe expressive communication impairments characterized by an expressive vocabulary of < 10 words. The online CMPDP included webinars, coursework, and engagement with an online community of practice. We examined the students' expressive communication skills measured by the Communication Matrix Assessment and Individualized Education Program (IEP) goal quality measured by the Design to Learn IEP Goal Development Guide before and after their teachers and speech-language pathologists participated in the intervention.

Results

Students showed small but significant increases on the Communication Matrix Assessment. The average increase in scores was 10.6,
z
= 5.37, 95% confidence interval (CI; [6.65, 14.54]), Glass's delta = 0.37. The mean gain in scores for IEP quality was not significant (0.82,
z
= 2.43, 95% CI [0.14, 1.49], Glass's delta = 0.28).

Conclusions

Results demonstrate the initial feasibility of the CMPDP for educational professionals and their students with complex communication needs. Findings must be interpreted cautiously as the study design has methodological limitations including lack of a control condition and a potential for correlated measurement error and demand characteristics.

Supplemental Material

https://doi.org/10.23641/asha.16734553
“Two Friends Spending Time Together”: The Impact of Video Visual Scene Displays on Peer Social Interaction for Adolescents With Autism Spectrum Disorder
Authors: Babb Salena , McNaughton David , Light Janice , Caron Jessica
Published: October 2021

Purpose

Social interaction poses many challenges for adolescents with autism spectrum disorder (ASD) and complex communication needs. The purpose of this study was to investigate the impact of video visual scene displays (video VSDs) on communication during interactions between adolescents with ASD and peer partners.

Method

This study used an across-participant multiple-baseline single-case experimental design. Four adolescents with ASD and complex communication needs were taught to use video VSDs, presented on a tablet-based app, during social interactions with peer partners in a high school setting. The video VSDs used during the interactions were selected (and programmed with vocabulary) based on the interests of the adolescent with ASD and their peer partner.

Results

Following the introduction of the video VSD intervention, all four adolescents with ASD demonstrated an increase in communicative turns compared to baseline (Tau-
U
= 1.0, 95% CI [0.56, 1]), and all four increased in modes of communication used. Increased use of speech also was observed for the three participants who made use of speech prior to the intervention. All participants with ASD (and their peer partners) expressed an interest in continued use of the video VSD app to support social interaction.

Conclusion

The use of video VSDs may be a viable option to increase the participation and communication of adolescents with ASD during social interactions with peer partners.

Supplemental Material

https://doi.org/10.23641/asha.16734532
Blind detection of cyclostationary signals based on multi‐antenna beamforming technology
Authors: Wang Jie , Gao Rui , Ye Ding , Zhang Zhenghua
Published: October 2021

Cyclostationary feature detection is one of the widely used spectrum sensing techniques. Its greatest advantage is that it can effectively separate the signal from the noise under the condition of a low signal‐noise ratio (SNR). Although cyclostationary feature detection is not affected by noise uncertainty like energy detection (ED), conventional cyclic stationary feature detection needs to know the prior conditions of signal cycle frequency (CF), cycle period, and so on. Moreover, the communication signals of authorized users are generally weak, which greatly affects the detection efficiency of cyclic stationary features. Therefore, this paper proposes a blind detection technique of cyclostationary characteristics based on conventional beam synthesis multi‐antenna. The principle is to enhance the signal receiving intensity of the antenna by using beamforming technology, and realize the blind detection of cyclostationary signals by forming the direction of arrival angle. Not only that, the authors also make full use of the Wilk's approximation theorem and the generalized likelihood ratio test (GLRT) to derive the detection probability and false alarm probability. The simulation results show that the proposed cyclic stationary signal detector based on beam synthesis multi‐antenna can realize blind detection of unknown cycle signals in a low SNR environment.
Compact eighth‐mode ridged substrate integrated waveguide filter
Authors: Liu Liguo , Huang Liwen
Published: October 2021

In this letter, a novel eighth‐mode ridged substrate integrated waveguide (EMRSIW) is proposed by bisecting the RSIW resonator along the virtual magnetic walls. The EMRSIW shows a size of nearly one‐eighth of a conventional RSIW resonator and a significant size reduction compared to the conventional eighth‐mode SIW resonator. A prototype of a third‐order bandpass filter with transmission zeros has been designed and tested.
Design of compact microstrip bandpass filter with two switchable operating passbands
Authors: Chen Chi‐Feng , Tseng Hsin‐Ya , He Yi‐Hua , Li Wen‐Jie
Published: October 2021

A new bandpass filter (BPF) with two switchable operating passbands has been proposed. The BPF topology is formed by switchable resonators and stepped‐impedance resonators. The two operating bands can be switched on and off independently. For verification, a switchable BPF with a third‐order Chebyshev bandpass response was designed and fabricated using microstrip technology. The developed BPF was measured to verify the predicted and simulated results. A close agreement was observed between them. The proposed switchable BPF has good in‐band and out‐of‐band performances. Besides, the attenuation is > 30 dB as the passband is switched off.
Simulations of radio-wave anisotropic scattering to interpret type III radio burst data from Solar Orbiter, Parker Solar Probe, STEREO, and Wind
Authors: Musset S. , Maksimovic M. , Kontar E. , Krupar V. , Chrysaphi N. , Bonnin X. , Vecchio A. , Cecconi B. , Zaslavsky A. , Issautier K. , Bale S. D. , Pulupa M.
Published: October 2021

Aims. We use multi-spacecraft observations of individual type III radio bursts to calculate the directivity of the radio emission. We compare these data to the results of ray-tracing simulations of the radio-wave propagation and probe the plasma properties of the inner heliosphere.

Methods. We used ray-tracing simulations of radio-wave propagation with anisotropic scattering on density inhomogeneities to study the directivity of radio emissions. Simultaneous observations of type III radio bursts by four widely separated spacecraft were used to calculate the directivity and position of the radio sources. The shape of the directivity pattern deduced for individual events is compared to the directivity pattern resulting from the ray-tracing simulations.

Results. We show that simultaneous observations of type radio III bursts by four different probes provide an opportunity to estimate the radio source positions and the directivity of the radio emission. The shape of the directivity varies from one event to another and it is consistent with anisotropic scattering of the radio waves.
Magnetic reconnection as a mechanism to produce multiple thermal proton populations and beams locally in the solar wind
Authors: Lavraud B. , Kieokaew R. , Fargette N. , Louarn P. , Fedorov A. , André N. , Fruit G. , Génot V. , Réville V. , Rouillard A. P. , Plotnikov I. , Penou E. , Barthe A. , Prech L. , Owen C. J. , Bruno R. , Allegrini F. , Berthomier M. , Kataria D. , Livi S. , Raines J. M. , D’Amicis R. , Eastwood J. P. , Froment C. , Laker R. , Maksimovic M. , Marcucci F. , Perri S. , Perrone D. , Phan T. D. , Stansby D. , Stawarz J. , Toledo-Redondo S. , Vaivads A. , Verscharen D. , Zouganelis I. , Angelini V. , Evans V. , Horbury T. S. , O’Brien H.
Published: October 2021

Context.Spacecraft data revealed early on the frequent observation of multiple near-thermal proton populations in the solar wind. Decades of research on their origin have focused on processes such as magnetic reconnection in the low corona and wave-particle interactions in the corona and locally in the solar wind.

Aims.This study aims to highlight the fact that such multiple thermal proton populations and beams are also produced by magnetic reconnection occurring locally in the solar wind.

Methods.We used high-resolution Solar Orbiter proton velocity distribution function measurements, complemented by electron and magnetic field data, to analyze the association of multiple thermal proton populations and beams with magnetic reconnection during a period of slow Alfvénic solar wind on 16 July 2020.

Results.At least six reconnecting current sheets with associated multiple thermal proton populations and beams, including a case of magnetic reconnection at a switchback boundary, were found on this day. This represents 2% of the measured distribution functions. We discuss how this proportion may be underestimated, and how it may depend on solar wind type and distance from the Sun.

Conclusions.Although suggesting a likely small contribution, but which remains to be quantitatively assessed, Solar Orbiter observations show that magnetic reconnection must be considered as one of the mechanisms that produce multiple thermal proton populations and beams locally in the solar wind.
Variation of the stellar color in high-magnification and caustic-crossing microlensing events
Authors: Sajadian S. , Jørgensen U. G.
Published: October 2021

Context. To a first approximation, the microlensing phenomenon is achromatic and great advancements have been achieved with regard to the interpretation of the achromatic signals, leading to the discovery and characterization of well above 100 new exoplanets. At a higher order accuracy in the observations, microlensing has a chromatic component (a color term) that has thus far been explored to a much lesser extent.

Aims. Here, we analyze the chromatic microlensing effect of four different physical phenomena, which have the potential to contribute key knowledge of the stellar properties that is not easily achievable with other methods of observation. Our simulation is limited to the case of main-sequence source stars.

Methods. Microlensing is particularly sensitive to giant and sub-giant stars near the Galactic center. While this population can be studied in short snapshots by the largest telescopes in the world, a general monitoring and characterization of the population can be achieved by use of more accessible medium-sized telescopes with specialized equipment via dual-color monitoring from observatories at sites with excellent seeing. We limit the results of this study to what will be achievable from the Danish 1.54 m telescope at La Silla observatory based on the use of the existing dual-color lucky imaging camera. Such potential monitoring programs of the bulge population from medium-sized telescopes include the characterization of starspots, limb-darkening, the frequency of close-in giant planet companions, and gravity darkening for blended source stars.

Results. We conclude our simulations with quantifying the likelihood of detecting these different phenomena per object where they are present to be ~60 and ~30% for the above-mentioned phenomena when monitored during both high-magnification and caustic crossings, respectively.
Gas phase Elemental abundances in Molecular cloudS (GEMS) V. Methanol in Taurus
Authors: Spezzano S. , Fuente A. , Caselli P. , Vasyunin A. , Navarro-Almaida D. , Rodríguez-Baras M. , Punanova A. , Vastel C. , Wakelam V.
Published: October 2021

Context. Methanol, one of the simplest complex organic molecules in the interstellar medium, has been shown to be present and extended in cold environments such as starless cores. Studying the physical conditions at which CH3OH starts its efficient formation is important to understand the development of molecular complexity in star-forming regions.

Aims. We aim to study methanol emission across several starless cores and investigate the physical conditions at which methanol starts to be efficiently formed, as well as how the physical structure of the cores and their surrounding environment affect its distribution.

Methods. Methanol and C18O emission lines at 3 mm have been observed with the IRAM 30 m telescope within the large programme Gas phase Elemental abundances in Molecular CloudS towards 66 positions across 12 starless cores in the Taurus Molecular Cloud. A non-LTE (local thermodynamic equilibrium) radiative transfer code was used to compute the column densities in all positions. We then used state-of-the-art chemical models to reproduce our observations.

Results. We have computed N(CH3OH)/N(C18O) column density ratios for all the observed offsets, and the following two different behaviours can be recognised: the cores where the ratio peaks at the dust peak and the cores where the ratio peaks with a slight offset with respect to the dust peak (~10 000 AU). We suggest that the cause of this behaviour is the irradiation on the cores due to protostars nearby which accelerate energetic particles along their outflows. The chemical models, which do not take irradiation variations into account, can reproduce the overall observed column density of methanol fairly well, but they cannot reproduce the two different radial profiles observed.

Conclusions. We confirm the substantial effect of the environment on the distribution of methanol in starless cores. We suggest that the clumpy medium generated by protostellar outflows might cause a more efficient penetration of the interstellar radiation field in the molecular cloud and have an impact on the distribution of methanol in starless cores. Additional experimental and theoretical work is needed to reproduce the distribution of methanol across starless cores.
Discovery of interstellar 3-cyano propargyl radical, CH2CCCN
Authors: Cabezas C. , Agúndez M. , Marcelino N. , Tercero B. , Pardo J. R. , de Vicente P. , Cernicharo J.
Published: October 2021

We report the first detection in interstellar space of the 3-cyano propargyl radical (CH2C3N). This species was observed in the cold dark cloud TMC-1 using the Yebes 40m telescope. A total of seven rotational transitions for both ortho- and para-CH2C3N species were observed in the 31.0–50.4 GHz range. We derive a total column density of (1.6 ± 0.4) × 1011 cm−2 and an ortho/para ratio of 2.4 ± 1.2, which implies an abundance ratio CH2C3N/CH3C3N ∼ 0.1, in sharp contrast with the smaller analogues, in which case CH2CN/CH3CN ∼ 3. This indicates that the chemistry of the cyanides CH2C3N and CH3C3N behaves differently to that of the smaller analogues CH2CN and CH3CN. According to our chemical model calculations, the radical CH2C3N is mostly formed through the neutral-neutral reactions C + CH2CHCN, C2 + CH3CN, and CN + CH2CCH together with the dissociative recombination of the CH3C3NH+ ion with electrons. The neutral-neutral reaction N + C4H3 could also lead to CH2C3N, although its role is highly uncertain. The identified radical CH2C3N could play a role in the synthesis of large organic N-bearing molecules, such as benzonitrile (c–C6H5CN) or nitrogen heterocycles.
Aide de l’imagerie 3D pour le diagnostic d’une Classe II asymétrique
Authors: Petitpas Laurent , Harter Hugo
Published: October 2021

Depuis maintenant plusieurs années, nous pouvons compter sur l’utilisation des outils numériques d’imagerie 3D pour affiner un diagnostic orthodontique qui se veut de plus en plus précis.

Ces différents outils 3D permettent de mettre en évidence de manière plus importante les dysmorphoses, notamment en visualisant le siège de nombreuses asymétries, et ce grâce à la réalisation de superpositions 3D des empreintes optiques et des enregistrements de CBCT (Cone Beam Computed Tomography).

Cet article montre de nombreuses possibilités quant à la visualisation d’un patient virtualisé en 3D présentant une Classe II asymétrique dentaire et diverses dysmorphoses.
Sicherer Babyschlaf: Europäische Empfehlungen auf dem Prüfstand
Authors: Singer Dominique
Published: October 2021

Liebe Leserinnen und Leser

das „Bed-sharing“, mitunter auch als „Co-sleeping“ bezeichnet, also der gemeinsame Schlaf von Mutter/Vater und Kind (<1 Jahr) im gleichen Bett, gilt – unter anderem wegen der drohenden Behinderung der freien Atmung – als Risikofaktor für den plötzlichen Säuglingstod, sodass in vielen Empfehlungen zum „sicheren Babyschlaf“ mehr oder weniger pauschal davon abgeraten wird. Dies steht in gewissem Kontrast zu der Tatsache, dass das Bed-sharing weltweit enorm verbreitet ist, und lässt vielleicht auch andere Faktoren, wie die Rolle des kindlichen Alters oder die Auswirkungen auf die mütterliche Stillbereitschaft, zu sehr außer Acht. In einer interessanten Übersichtsarbeit im „Fokus Hebammenwissenschaft“ dieser Zeitschrift werden daher die Empfehlungen zur Prophylaxe des Sudden Infant Death Syndrome (SIDS) in Europäischen Ländern mit besonders niedriger (Griechenland, Italien, Niederlande) und besonders hoher SIDS-Inzidenz (UK, Österreich, Frankreich) analysiert und der aktuellen Evidenzlage gegenübergestellt. Es zeigt sich, dass, was empfohlen bzw. nicht empfohlen wird, nicht immer der wissenschaftlichen Evidenz entspricht, und dass ein sorgfältigerer Abgleich, so zumindest die Folgerung der Autorinnen, auch differenziertere Empfehlungen gerade zum Thema Bed-sharing erlauben würde.
Antwort auf den Leserbrief zum Beitrag: Qualität der Versorgung sehr kleiner Frühgeborener in Deutschland – Auswertung öffentlich verfügbarer Daten der Perinatalzentren von 2014 bis 2018
Authors: Trotter Andreas
Published: October 2021

Sehr geehrte Autoren des Leserbriefes, bzgl. o.g. Arbeit [1] gehe ich gerne auf die einzelnen Punkte ein.
Study on the rheology of a dilute emulsion of surfactant-covered droplets using the level set and closest point methods
Authors: Pimenta P. H. N. , Oliveira T. F.
Published: October 2021

In this work, we study the effects of surfactant elasticity (E), coverage factor (X), and Péclet number (Pe) on the droplet shape and emulsion rheology. Our analysis considers a single two-dimensional surfactant-covered droplet in an immiscible liquid submitted to a simple shear flow. The numerical methodology combines the level set, to capture the interface, and the closest point method to solve the surfactant transport equation. We separate the dilute phase contribution to the bulk stress tensor in the capillary stress, associated with the normal stress jump, and the Marangoni stress, related to the stress tangent to the interface. Our results show that E and X affect the droplet shape more intensely than the Pe. On the other hand, Pe directly affects the emulsion's bulk viscosity. For Pe≫1, the capillary viscosity decreases with X, while the Marangoni viscosity grows with X. Such a compensation mechanism allows the increase in the bulk viscosity with X. We also present results for the first normal stress difference.
Wall-modeled lattice Boltzmann large-eddy simulation of neutral atmospheric boundary layers
Authors: Asmuth Henrik , Janßen Christian F. , Olivares-Espinosa Hugo , Ivanell Stefan
Published: October 2021

The lattice Boltzmann method (LBM) sees a growing popularity in the field of atmospheric sciences and wind energy, largely due to its excellent computational performance. Still, LBM large-eddy simulation (LES) studies of canonical atmospheric boundary layer flows remain limited. One reason for this is the early stage of development of LBM-specific wall models. In this work, we discuss LBM–LES of isothermal pressure-driven rough-wall boundary layers using a cumulant collision model. To that end, we also present a novel wall modeling approach, referred to as inverse momentum exchange method (iMEM). The iMEM enforces a wall shear stress at the off-wall grid points by adjusting the slip velocity in bounce-back boundary schemes. In contrast to other methods, the approach does not rely on the eddy viscosity, nor does it require the reconstruction of distribution functions. Initially, we investigate different aspects of the modeling of the wall shear stress, i.e., an averaging of the input velocity as well as the wall-normal distance of its sampling location. Particularly, sampling locations above the first off-wall node are found to be an effective measure to reduce the occurring log-layer mismatch. Furthermore, we analyze the turbulence statistics at different grid resolutions. The results are compared to phenomenological scaling laws, experimental, and numerical references. The analysis demonstrates a satisfactory performance of the numerical model, specifically when compared to a well-established mixed pseudo-spectral finite difference (PSFD) solver. Generally, the study underlines the suitability of the LBM and particularly the cumulant LBM for computationally efficient LES of wall-modeled boundary layer flows.
COVID-19 prompts rapid and safe transition of chemotherapy into homes
Authors: Vanlint Andrew S. , Adams Julie , Price Timothy
Published: October 2021

With the identification of the COVID-19 pandemic in early 2020, cancer-based clinical services in South Australia moved quickly to protect patients on active anti-cancer treatment who are particularly vulnerable to infective complications. This took the form of shifting 600 chemotherapy visits into the patients’ homes via expansion of an existing arrangement between a public hospital network and an established private home chemotherapy service. Despite calls for caution from some oncology organisations and a relative paucity in specific clinical data supporting this approach, it proved to be a safe and efficient transition with additional unexpected benefits.
A world without pythons would be so simple
Authors: Engelhardt Netta , Penington Geoff , Shahbazi-Moghaddam Arvin
Published: October 2021

We show that bulk operators lying between the outermost extremal surface and the asymptotic boundary admit a simple boundary reconstruction in the classical limit. This is the converse of the Python’s lunch conjecture, which proposes that operators with support between the minimal and outermost (quantum) extremal surfaces—e.g. the interior Hawking partners—are highly complex. Our procedure for reconstructing this ‘simple wedge’ is based on the HKLL construction, but uses causal bulk propagation of perturbed boundary conditions on Lorentzian timefolds to expand the causal wedge as far as the outermost extremal surface. As a corollary, we establish the Simple Entropy proposal for the holographic dual of the area of a marginally trapped surface as well as a similar holographic dual for the outermost extremal surface. We find that the simple wedge is dual to a particular coarse-grained CFT state, obtained via averaging over all possible Python’s lunches. An efficient quantum circuit converts this coarse-grained state into a ‘simple state’ that is indistinguishable in finite time from a state with a local modular Hamiltonian. Under certain circumstances, the simple state modular Hamiltonian generates an exactly local flow; we interpret this result as a holographic dual of black hole uniqueness.
Positron elastic scattering by a semifilled-shell atom*
Authors: Amusia M Ya , Dolmatov V K , Chernysheva L V
Published: October 2021

We theoretically study the positron elastic scattering by an atom with a multielectron semifilled subshell in its structure. We focus on gaining the initial insight into the specifics of such a process. The positron scattering by the Mn(…3d54s2, 6S) atom with a 3d5 semifilled subshell (e+ + Mn scattering) is chosen as a case study. We account for both the electron correlation and the formation of a e+ + e− virtual positronium (Ps) in the intermediate states of the e+ + Mn system. Electron correlation is taken into account in the framework of the self-energy part of the scattering positron Green function generalized for the application to semifilled-shell atoms. The influence of the virtual Ps formation on the positron scattering is taken into account by the reduction of the energy of the virtual positron plus atomic-excited-configuration states by the Ps-binding energy, to a reasonable approximation. We unravel the importance and specificity of the influence of both the virtual Ps and electron correlation on e+ + Mn elastic scattering. We demonstrate spectacular differences between the electron and positron scattering processes.
Polarization in strong-field ionization of excited helium
Authors: Bray A C , Maxwell A S , Kissin Y , Ruberti M , Ciappina M F , Averbukh V , Figueira De Morisson Faria C
Published: October 2021

We analyze how bound-state excitation, electron exchange and the residual binding potential influence above-threshold ionization (ATI) in helium prepared in an excited p state, oriented parallel and perpendicular to a linearly polarized mid-IR field. Using the ab initio B-spline algebraic diagrammatic construction, and several one-electron methods with effective potentials, including the Schrödinger solver Qprop, modified versions of the strong-field approximation (SFA) and the Coulomb quantum-orbit strong-field approximation, we find that these specific physical mechanisms leave significant imprints in ATI spectra and photoelectron momentum distributions. Examples are changes of up to two orders of magnitude in the high-energy photoelectron region, and ramp-like structures that can be traced back to Coulomb-distorted trajectories. The present work also shows that electron exchange renders rescattering less effective, causing suppressions in the ATI plateau. Due to the long-range potential, the electron continuum dynamics are no longer confined to the polarization axis, in contrast to the predictions of traditional approaches. Thus, one may in principle probe excited-state configurations perpendicular to the driving-field polarization without the need for orthogonally polarized fields.
Three-dimensional tomographic imaging of CO molecular orbitals reveals multi-electron effects
Authors: Ren Zhongxue , Yang Yan , Zhu Yalei , Zan Xiaolei , Zhao Jing , Zhao Zengxiu
Published: October 2021

According to the asymmetric molecular orbital reconstruction algorithm, which divides orbital into gerade and ungerade components and which does not depend on the unidirectional recollisional condition, we obtain the two-dimensional highest occupied molecular orbital (HOMO) of CO based on the directly calculated transition dipole moment and the harmonic spectra calculated by the Lewenstein model, respectively, which is the three-dimensional (3D) HOMO projected onto the plane perpendicular to the laser propagation direction. In order to retrieve the full orbital function, a 3D molecular orbital tomography (MOT) method is developed and is successfully applied to the reconstructions of the HOMO of CO, which simplifies the 3D imaging process of orbitals of linear molecules, and is expected to be extended to reconstruct the 3D orbitals of nonlinear molecules. In addition, the time-dependent density functional theory is employed to acquire the harmonic spectra of CO in a 800 nm and 1500 nm wavelength laser, respectively. The comparison of these two reconstruction results helps identify the multi-electron effects for asymmetric MOT, which requires further study. This work advances the development of MOT and is expected to reveal multi-electron effects in orbital imaging of complex polyatomic molecules.
Pressure-induced metal–insulator transition in oxygen-deficient LiNbO3-type ferroelectrics
Authors: Xia Chengliang , Chen Yue , Chen Hanghui
Published: October 2021

Hydrostatic pressure and oxygen vacancies usually have deleterious effects on ferroelectric materials because both tend to reduce their polarization. In this work we use first-principles calculations to study an important class of ferroelectric materials—LiNbO3-type ferroelectrics (LiNbO3 as the prototype), and find that in oxygen-deficient LiNbO3−δ
, hydrostatic pressure induces an unexpected metal–insulator transition between 8 and 9 GPa. Our calculations also find that strong polar displacements persist in both metallic and insulating oxygen-deficient LiNbO3−δ
and the size of polar displacements is comparable to pristine LiNbO3 under the same pressure. These properties are distinct from widely used perovskite ferroelectric oxide BaTiO3, whose polarization is quickly suppressed by hydrostatic pressure and/or oxygen vacancies. The anomalous pressure-driven metal–insulator transition in oxygen-deficient LiNbO3−δ
arises from the change of an oxygen vacancy defect state. Hydrostatic pressure increases the polar displacements of oxygen-deficient LiNbO3−δ
, which reduces the band width of the defect state and eventually turns it into an in-gap state. In the insulating phase, the in-gap state is further pushed away from the conduction band edge under hydrostatic pressure, which increases the fundamental gap. Our work shows that for LiNbO3-type strong ferroelectrics, oxygen vacancies and hydrostatic pressure combined can lead to new phenomena and potential functions, in contrast to the harmful effects occurring to perovskite ferroelectric oxides such as BaTiO3.
Variability of indoor radon concentration in UK homes
Authors: Daraktchieva Z
Published: October 2021

This study investigated the variability of indoor radon concentrations in 518 100 homes in the UK. The statistical analysis included measurements in 395 720 homes with downstairs living rooms and upstairs bedrooms. The radon concentration in these bedrooms was found to be on average 63% of the living room value. The analysis of 122 380 homes with living rooms and bedrooms situated on the same floor found that there is a small difference in radon concentration of 9% between the two rooms. The results showed that the ratios of the living room to bedroom radon concentrations were approximately lognormally distributed. The geometric mean of the ratio was found to be 1.6 for rooms situated on different storeys and 1.1 for rooms situated on the same floor. It was found that house characteristics and energy efficiency measures affect the distribution of radon within homes. Detached houses and those with suspended floors had higher radon levels in their upstairs bedroom, 66.7% and 76.9% of the downstairs living room values, respectively. For homes built between 1993 and 2007, the bedroom to living room ratio increased from 58.8% to 76.9% due to the increased airtightness and improved energy performance of the modern buildings. Homes with installed wall and loft insulation had much higher bedroom to living room ratio (76.9%) than those without energy efficiency measures (52.6%).
Unlocking active metal site of Ti-MOF for boosted heterogeneous catalysis via a facile coordinative reconstruction
Authors: Liu Wenxian , Que Wenbin , Shen Xuhai , Yin Ruilian , Xu Xilian , Zheng Dong , Feng Jinxiu , Dai Xiaojing , Niu Xinxin , Wu Fangfang , Shi Wenhui , Cao Xiehong
Published: October 2021

Constructing sophisticated hollow structure and exposing more metal sites in metal-organic frameworks (MOFs) can not only enhance their catalytic performance but also endow them with new functions. Herein, we present a facile coordinative reconstruction strategy to transform Ti-MOF polyhedron into nanosheet-assembled hollow structure with a large amount of exposed metal sites. Importantly, the reconstruction process relies on the esterification reaction between the organic solvent, i.e. ethanol and the carboxylic acid ligand, allowing the conversion of MOF without the addition of any other modulators and/or surfactants. Moreover, the surface and internal structure of the reconstructed MOF can be well tuned via altering the conversion time. Impressively, the reconstructed MOF exhibits ∼5.1-fold rate constant compared to the pristine one in an important desulfurization reaction for clean fuels production, i.e. the oxidation of dibenzothiophene.
Recent advances in 2D graphene reinforced metal matrix composites
Authors: Chen Rong , Zhou Xing
Published: October 2021

The unique combination of excellent mechanical and functional properties makes graphene an ideal component for high-performance ‘smart’ composites, which are sensitive to thermal, optical, electrical and mechanical excitations, hence being potential in application of a range of sensors. It has confirmed that the addition of graphene into metal matrix can significantly enhance the mechanical property and deliver surprising functional properties. Thus, graphene reinforced metal matrix composites (GMMCs) have long been regarded as potential prospects of nanotechnology applications. Recently, researchers mainly focused on: (i) solving the interfacial issues and realizing controllable alignment of graphene in metal matrix to achieve optimal performance; (ii) reasonable designing of the microstructures basing on usage requirement and then fabricating via efficient technique. Thus, it is necessary to figure out key roles of microstructure in fabrication process, mechanical and multi-functional properties. This review consists of four parts: (i) fabrication process. The fabrication processes are firstly divided into three kinds basing on the different bonding nature between graphene and metal matrix. (ii) Mechanical property. The microstructural characteristics of metal matrix accompanying by the incorporation of graphene and their vital effects on mechanical properties of GMMCs are systematically summarized. (iii) Functional property. The crucial effects of microstructure on electrical and thermal properties are summarized. (iv) Prospect applications and future challenges. Application and challenges basing on the research status are discussed to provide useful directions for future exploration in related fields. All these four parts are discussed with a focus on key role of microstructure characteristics, which is instructive for the microstructures design and fabrication process optimization during academic researches and potential commercial applications.
In situ control of graphene oxide dispersions with a small impedance sensor
Authors: Dimou Angeliki Eirini , Maistros George , Poulin Philippe , Alexopoulos Nikolaos D
Published: October 2021

Carbon-based nanomaterials (CBNs), such as graphene and carbon nanotubes, display advanced physical and chemical properties, which has led to their widespread applications. One of these applications includes the incorporation of CBNs into cementitious materials in the form of aqueous dispersions. The main issue that arises in this context is that currently no established protocol exists as far as characterizing the dispersions. In the present article, an innovative method for quick evaluation and quantification of graphene oxide (GO) dispersions is proposed. The proposed method is electrical impedance spectroscopy (EIS) with an impedance sensor. The novelty lies on the exploitation of a small sensor for on-site (field) direct dielectric measurements with the application of alternating current. Five different concentrations of GO dispersions were studied by applying EIS and for various accumulated ultrasonic energies. The low GO concentration leads to high impedance values due to low formed current network. Two opposing mechanisms were revealed during the accumulation of ultrasonic energy, that are taking place simultaneously: breakage of the agglomerates that facilitates the flow of the electric current due to the formation of a better dispersed network, nevertheless the surface hydrophilic structure of the GO is damaged with the high accumulated ultrasonic energy. The dielectric measurements were exploited to express an appropriate quantitative ‘quality index’ to facilitate with the dispersion control of the nanostructures. An intermediate concentration of GO is suggested (about 0.15 wt% of the binder materials) to be optimal for the specific engineering application, ultrasonicated at approximately 30 to 65 kJ. The investigated methodology is highly novel and displays a high potential to be applied in-field applications where CBNs must be incorporated in building materials.
Electron-positron pair production in the collision of real photon beams with wide energy distributions
Authors: Esnault L , d’Humières E , Arefiev A , Ribeyre X
Published: October 2021

The creation of an electron–positron pair in the collision of two real photons, namely the linear Breit–Wheeler process, has never been detected directly in the laboratory since its prediction in 1934 despite its fundamental importance in quantum electrodynamics and high energy astrophysics. In the last few years, several experimental setup have been proposed to observe this process in the laboratory, relying either on thermal radiation, Bremsstrahlung, linear or multiphoton inverse Compton scattering photons sources created by lasers or by the mean of a lepton collider coupled with lasers. In these propositions, the influence of the photons’ energy distribution on the total number of produced pairs has been taken into account with an analytical model only for two of these cases. We hereafter develop a general and original, semi-analytical model to estimate the influence of the photons energy distribution on the total number of pairs produced by the collision of two such photon beams, and give optimum energy parameters for some of the proposed experimental configurations. Our results shows that the production of optimum Bremsstrahlung and linear inverse Compton sources are, only from energy distribution considerations, already reachable in today’s facilities. Despite its less interesting energy distribution features for the linear Breit–Wheeler pair production, the photon sources generated via multiphoton inverse Compton scattering by the propagation of a laser in a micro-channel can also be interesting, thank to the high collision luminosity that could eventually be reached by such configurations. These results then gives important insights for the design of experiments intended to detect linear Breit–Wheeler produced positrons in the laboratory for the first time.
Collisional and transport parameters of Cu in the warm dense matter regime calculated using the average atom model
Authors: Petrov G M , Davidson A
Published: October 2021

Collisional and transport parameters for Cu are computed using the average atom model. Transition metals such as copper are difficult to model within the framework of the average atom model due to the presence of a narrow band of 3d electrons that mix and hybridize with the broad 4s band of nearly-free electrons. With electron temperature increasing, the 3d electrons play a key role in the thermodynamics and transport properties of Cu (Lin et al 2008 Phys. Rev. B 77 075133), as well as the stability of the lattice (Loboda et al 2011 High Energy Density Phys.
7 361). In this work, the average atom model was used to track the average energy of the 3d band and its evolution with electron temperature. At room temperature, its center is at ∼6 electron volts (eV), a few electron-volts below the Fermi energy, and with electron temperature increasing it sinks relative to it. At electron temperature of about 8 eV the 3d electrons leave the conduction band and become bound. A long-standing problem related to the average ion charge observed by conduction band electrons is addressed and successfully resolved. A work-around has been found that predicts the correct average ion charge,

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, by formally introducing a third group of electrons: quasi-bound electrons. Benchmarking with published data is made that shows good agreement.
Two-fluid approach to weak plasma turbulence
Authors: Yoon Peter H
Published: October 2021

Weakly turbulent processes that take place in plasmas are customarily formulated in terms of kinetic theory. However, owing to an inherent complexity associated with the problem, thus far the theory is fully developed largely for unmagnetized plasmas. In the present paper it is shown that a warm two fluid theory can successfully be employed in order to partially formulate the weak turbulence theory in spatially uniform plasma. Specifically, it is shown that the nonlinear wave-wave interaction, or decay processes, can be reproduced by the two-fluid formalism. The present finding shows that the same approach can in principle be extended to magnetized plasmas, which is a subject of future work.
A full-field optical crazimeter
Authors: Kumar Raj , Varshney Tushar , Yadav Tarun , Dwivedi Gaurav , Barve S K , Singh Omendra
Published: October 2021

Quantification of crazing in optical components made of glassy polymers is important as crazing degrades a component’s optical performance and mechanical strength. The present work describes a single-beam-based full-field optical crazimeter for imaging and quantification of crazes in transparent samples of plastic using the principles of Fourier optics. A collimated laser beam passes through the sample and acquires information about crazes present in it. A specially designed and fabricated spatial bandpass filter is used in the 4f optical information processing setup to image crazes present in the sample and reject the noise signal. Digital image processing is used to extract quantitative information about craze density from the recorded images. The proposed crazimeter may enable full-field inspection of consumer products made of various transparent plastics for the presence of crazes.
Vanadium dioxide-assisted switchable broadband terahertz metasurface for polarization conversion and phase modulation
Authors: Li Yun , Zhang Heng , Li Tongtong , Zhang Bin
Published: October 2021

Switchable metasurfaces with diversified functionalities have become an emerging research area owing to its potential for realizing integrated and miniature meta-devices. Although great efforts have been devoted in this area, switchable metasurfaces with diversified functionalities still require dealing with formidable challenges. In this paper, a switchable broadband terahertz (THz) metasurface with multiple functionalities is proposed utilizing the phase transition property of vanadium dioxide (VO2), and it can switch functionalities by changing the state of VO2 from metal to insulator thermally. The simulation results demonstrate that when VO2 is in metallic state at the temperature of 400 K, the designed metasurface works as a half wave plane with polarization conversion ratio more than 90% at THz frequency band ranging from 0.66 to 1.44 THz. When VO2 is in insulating state at the temperature of 300 K, the metasurface can flexibly control the phase of the THz wave. As a proof of concept, several devices with high performance for realizing anomalous reflection, diffuse scattering, vortex beam and beam-focusing are numerically investigated. The proposed metasurface has potential applications in THz imaging, sensing and other intellectual systems for photonics integration.
Development of a reporter gene method to measure the bioactivity of anti-CD38 × CD3 bispecific antibody
Authors: Xiong Hui , Luo Fengyan , Zhou Pengfei , Yi Jizu
Published: October 2021

Background

A T cell-redirecting bispecific antibody (bsAb) consisting of a tumor-binding unit and a T cell-binding unit is a large group of antibody-based biologics against death-causing cancer diseases. The anti-CD38 × anti-CD3 bsAb (Y150) is potential for treating multiple myeloma (MM). When developing a cell-based reporter gene bioassay to assess the activities of Y150, it was found that the expression of CD38 on the human T lymphocyte cells (Jurkat) caused the nonspecific activation, which interfered with the specific T cells activation of mediated by the Y150 and CD38(+) tumor cells.

Methods

Here, we first knocked-out the CD38 expression on Jurkat T cell line by CRISPR-Cas9 technology, then developed a stable monoclonal CD38(−) Jurkat T cell line with an NFAT-RE driving luciferase expressing system. Further based on the CD38(−) Jurkat cell, we developed a reporter gene method to assess the bioactivity of the anti-CD38 × anti-CD3 bsAb.

Results

Knocking out CD38 expression abolished the nonspecific self-activation of the Jurkat cells. The selected stable monoclonal CD38(−) Jurkat T cell line assured the robustness of the report genes assay for the anti-CD38 × anti-CD3 bsAb. The relative potencies of the Y150 measured by the developed reporter gene assay were correlated with those by the flow-cytometry-based cell cytotoxicity assay and by the ELISA-based binding assay.

Conclusions

The developed reporter gene assay was mechanism of action-reflective for the bioactivity of anti-CD38 × anti-CD3 antibody, and suitable for the quality control for the bsAb product.
A phylogeographical framework for Zhangixalus gliding frogs, with insight on their plasticity of nesting behaviour
Authors: Dufresnes Christophe , Ambu Johanna , Prasad Vishal Kumar , Borzée Amaël , Litvinchuk Spartak N
Published: October 2021

Old World tree frogs from the family Rhacophoridae, one of the most species-rich groups of amphibians worldwide, are becoming a model in ecological and evolutionary research, notably for their tremendous diversity of breeding systems. In this study, we provide the most comprehensive temporally and spatially explicit phylogeographical framework for the tropical neo-genus Zhangixalus, with a specific focus on the evolution of inter- and intraspecific polymorphism in their egg-laying strategies. We combined ~500 sequences spanning ~4 kb of mitochondrial genes, representative of nearly all known Zhangixalus species from 373 localities. We recovered a robust timetree featuring ~60 phylogeographical lineages assigned to 36 taxa, illustrating a vast under-appreciation of the diversity of the genus. Patterns of diversification were intimately linked to climatic trends since the Mid-Miocene, leading to a remarkable biogeographical scenario for the onset of Taiwanese diversity. Finally, in contrast to the macro-evolution of conserved breeding strategies in rhacophorids, the striking variation of nesting behaviour documented across Zhangixalus species, whereby foamy egg nests are alternatively fossorial, deposited on the edge of the water or suspended on the overhanging vegetation, seems to have evolved rapidly from arboreal ancestors in all major clades, implying micro-evolutionary processes and/or phenotypic plasticity.