bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamical signature of a stellar bulge in a quasar-host galaxy at z  ≃  6
Authors: Tripodi R. , Lelli F. , Feruglio C. , Fiore F. , Fontanot F. , Bischetti M. , Maiolino R.
Published: January 2023

We present a dynamical analysis of a quasar-host galaxy at z ≃ 6 (SDSS J2310+1855) using a high-resolution ALMA observation of the [CII] emission line. The observed rotation curve was fitted with mass models that considered the gravitational contribution of a thick gas disc, a thick star-forming stellar disc, and a central mass concentration, which is likely due to a combination of a spheroidal component (i.e. a stellar bulge) and a supermassive black hole (SMBH). The SMBH mass of 5 × 109 M⊙, previously measured using the CIV and MgII emission lines, is not sufficient to explain the high velocities in the central regions. Our dynamical model suggests the presence of a stellar bulge with a mass of Mbulge ∼ 1010 M⊙ in this object, when the Universe was younger than 1 Gyr. To finally be located on the local MSMBH − Mbulge relation, the bulge mass should increase by a factor of ∼40 from z = 6 to 0, while the SMBH mass should grow by a factor of 4 at most. This points towards asynchronous galaxy-BH co-evolution. Imaging with the JWST will allow us to validate this scenario.
Spectrum of the secondary component and new orbital elements of the massive triple star δ Ori A
Authors: Oplištilová A. , Mayer P. , Harmanec P. , Brož M. , Pigulski A. , Božić H. , Zasche P. , Šlechta M. , Pablo H. , Kołaczek-Szymański P. A. , Moffat A. F. J. , Lovekin C. C. , Wade G. A. , Zwintz K. , Popowicz A. , Weiss W. W.
Published: January 2023

δ Orionis is the closest massive multiple stellar system and one of the brightest members of the Orion OB association. The primary (Aa1) is a unique evolved O star. In this work, we applied a two-step disentangling method to a series of spectra in the blue region (430–450 nm), and we detected spectral lines of the secondary (Aa2). For the first time, we were able to constrain the orbit of the tertiary (Ab) – to 55 450 d or 152 yr – using variable γ velocities and new speckle interferometric measurements, which have been published in the Washington Double Star Catalogue. In addition, the Gaia DR3 parallax of the faint component (Ca+Cb) constrains the distance of the system to (381 ± 8) pc, which is just in the centre of the Orion OB1b association, at (382 ± 1) pc. Consequently, we found that the component masses according to the three-body model are 17.8, 8.5, and 8.7 M⊙, for Aa1, Aa2, and Ab, respectively, with the uncertainties of the order of 1 M⊙. We used new photometry from the BRITE satellites together with astrometry, radial velocities, eclipse timings, eclipse duration, spectral line profiles, and spectral energy distribution to refine radiative properties. The components, classified as O9.5 II + B2 V + B0 IV, have radii of 13.1, 4.1, and 12.0 R⊙, which means that δ Ori A is a pre-mass-transfer object. The frequency of 0.478 cycles per day, known from the Fourier analysis of the residual light curve and X-ray observations, was identified as the rotation frequency of the tertiary. δ Ori could be related to other bright stars in Orion, in particular, ζ Ori, which has a similar architecture, or ε Ori, which is a single supergiant, and possibly a post-mass-transfer object.
HARPS-N high spectral resolution observations of Cepheids
Authors: Nardetto N. , Gieren W. , Storm J. , Hocdé V. , Pietrzyński G. , Kervella P. , Mérand A. , Gallenne A. , Graczyk D. , Pilecki B. , Poretti E. , Rainer M. , Zgirski B. , Wielgórski P. , Hajdu G. , Górski M. , Karczmarek P. , Narloch W. , Taormina M.
Published: January 2023

Context. The Baade-Wesselink (BW) method of distance determination of Cepheids is used to calibrate the distance scale. Various versions of this method are mainly based on interferometry and/or the surface-brightness color relation (SBCR).

Aims. We quantify the impact of the SBCR, its slope, and its zero point on the projection factor. This quantity is used to convert the pulsation velocity into the radial velocity in the BW method. We also study the impact of extinction and of a potential circumstellar environment on the projection factor.

Methods. We analyzed HARPS-N spectra of η Aql to derive its radial velocity curve using different methods. We then applied the inverse BW method using various SBCRs in the literature in order to derive the BW projection factor.

Results. We find that the choice of the SBCR is critical: a scatter of about 8% is found in the projection factor for different SBCRs in the literature. The uncertainty on the coefficients of the SBCR affects the statistical precision of the projection factor only little (1–2%). Confirming previous studies, we find that the method with which the radial velocity curve is derived is also critical, with a potential difference on the projection factor of 9%. An increase of 0.1 in E(B − V) translates into a decrease in the projection factor of 3%. A 0.1 mag effect of a circumstellar envelope (CSE) in the visible domain is rather small on the projection factor, about 1.5%. However, we find that a 0.1 mag infrared excess in the K band due to a CSE can increase the projection factor by about 6%.

Conclusions. The impact of the surface-brightness color relation on the BW projection factor is found to be critical. Efforts should be devoted in the future to improve the SBCR of Cepheids empirically, but also theoretically, taking their CSE into account as well.
High-precision broadband linear polarimetry of early-type binaries
Authors: Abdul Qadir Yasir , Berdyugin Andrei V. , Piirola Vilppu , Sakanoi Takeshi , Kagitani Masato
Published: January 2023

Aims. The fact that the O-type close binary star system AO Cassiopeiae exhibits variable phase-locked linear polarization has been known since the mid-1970s. In this work, we re-observe the polarization arising from this system more than 50 yr later to better estimate the interstellar polarization and to independently derive the orbital parameters, such as inclination, i, orientation, Ω, and the direction of the rotation for the inner orbit from the phase-folded polarization curves of the Stokes q and u parameters.

Methods. The Dipol-2 polarimeter was used to obtain linear polarization measurements of AO Cassiopeiae in the B, V, and R passbands with the T60 remotely controlled telescope at an unprecedented accuracy level of ~0.003%. We have obtained the first proper quantification of the interstellar polarization in the direction heading towards AO Cas by observing the polarization of three neighboring field stars. We employed a Lomb-Scargle algorithm and detected a clear periodic signal for the orbital period of AO Cas. The standard analytical method based on a two-harmonics Fourier fit was used to obtain the inclination and orientation of the binary orbit.

Results. Our polarimetric data exhibited an unambiguous periodic signal at 1.76 days, thus confirming the orbital period of the binary system of 3.52 days. Most of the observed polarization is of interstellar origin. The de-biased values of the orbital inclination are i = 63° + 2°/−3° and orientation of Ω = 29º(209º) ± 8°. The direction of the binary system rotation on the plane of the sky is clockwise.
Spectroscopic investigation of interstellar hydrogenated carbon clusters
Authors: Dubosq Clément , Pla Paula , Dartois Emmanuel , Simon Aude
Published: January 2023

Context. The assignment of the mid-infrared (mid-IR) emission features and plateaus observed in C-rich and H-rich regions of the interstellar medium (ISM) is still debated. Such mid-IR assignments must also be related to their contribution to the extinction curve in our galaxy and to the ultraviolet (UV) bump.

Aims. The aim of this work is to investigate the influence of hydrogenation rate on the mid-IR spectra of populations of carbon clusters in order to constraint the nH/nC ratios in regions of the ISM where carbon is an important component. Their potential contribution to the extinction curve and in particular to the UV bump is also investigated.

Methods. The absorption IR and optical spectra of tens of thousands of C24Hn (n = 0, 6, 12, 18, 24) isomers classified into structural families – namely flakes, branched, pretzels, and cages – were computed using the density functional based tight binding electronic structure method and its time-dependent version, respectively. Final spectra were obtained by averaging the spectra of many individual isomers.

Results. The shapes and the relative intensities of the bands centered at ~3.25 and 3.40 µm and assigned to the C–H stretch of sp2 and sp3 carbon atoms, respectively, present a clear dependence on the nH/nC ratio. From a comparison with the astronomical spectrum from the Orion bar H2S1, the most interesting emitting candidates would pertain to the flakes population; this is the most energetically favorable family of clusters, possessing a high content of five and six carbon rings and being mostly planar, with no sp1 carbon atoms and with a nH/nC ratio of lower than 0.5. The same conclusion is drawn when comparing the computed IR features in the [4–20 µm] region with the observed plateaus from some C-rich and H-rich planetary nebulae objects of the Small Magellanic Cloud. The contribution of the same family could be considered for the UV bump. When nH/nC increases, only a contribution to the high-energy part of the continuum due to σ → π✶ excitations can reasonably be considered.

Conclusions. These results bring some constraints on the structural features and on the nH/nC ratio of the hydrogenated carbon populations emitting in the mid-IR domain in interstellar objects such as protoplanetary and reflection nebulae. The flakes population, with a low nH/nC ratio, is an interesting candidate for the carbon population emitting in these regions, but not for that absorbing in the diffuse ISM. None of the populations studied in the present work can account for the UV bump, but they would contribute to a broad extinction rise in this domain. The computed features reported in this article could be used to interpret future astronomical data provided by the James Webb Space Telescope.
Hydrochemical assessment of groundwater in the Kert aquifer using a GIS application: an overview of the control factors for fluoride, arsenic and silica enrichment
Authors: Gueddari Hicham , Akodad Mustapha , Baghour Mourad , Moumen Abdelmajid , El Yousfi Yassine , Ait Hmeid Hanane , Chahban Mohamed , Azizi Ghizlane , Benyoussef Said , Alitane Abdennabi , Riouchi Ouassila , Ngadi Hamza
Published: January 2023

Our study was based on using a freshwater aquatic species to assess the short-and long-term toxicity of an organophosphate insecticide commonly adopted by the Moroccan agriculture sector. Recently, groundwater pollution has emerged as one of the most severe environmental challenges, with a particular emphasis on levels of heavy metal pollution. Conservation efforts and efficient management of groundwater resources are required to determine the full scope of this damage. The current research answers the physical-chemical evaluation of the middle Kert basin’s water quality (Mediterranean area, Driouch province, Eastern Morocco) by collecting 42 samples and measuring pH, TDS that vary between 451 and 5841 mg/l, and EC that range from 0.72 to 9.41mS/cm2 according to ISO 5665. The samples were analyzed by ICP-MS and flame atomic absorption spectrometry to detect fluoride and arsenic content. Whose fluoride in the survey area varied from 0.01 mg/l to 2.85 mg/l. The hydro-chemical classification resulting from the Geographic Information System (GIS) statistical data analysis was used to interpret the analytical data on the phenomena responsible for the mineralization. This quantity is considerably higher than the maximum allowable level of 1.5 mg/L, which is the regulation for drinking water in Morocco. It indicates that both natural and artificial factors have contributed to the effects. Most stations have a fluoride concentration in the water, which can be used to identify them. It is a significant amount less than the values that would be ideal; just four wells have concentrations higher than the values that are legally allowed to be. The fluoride levels in the region’s water sources directly result from the natural elements that make up this particular geographic location.The same happened for arsenic, which exceeded 0.1 mg/l in just two samples.
Morphology and distribution of some marine diatoms of the genus Rhizosolenia in the lagoon of Nador (North East of Morroco)
Authors: Riouchi Ouassila , Skalli Ali , Akodad Mustapha , Moumen Abdelmajid , Azizi Ghizlane , Gueddari Hicham , EL Yousfi Yassine , Benyoussef Said , Chahban Mohamed , Baghour Mourad
Published: January 2023

This work aims to study the distribution and quantification of the genus Rhizosolenia known for its abundance and diversity among planktonic diatoms at 9 sampling stations in the Nador lagoon and during 2 seasons (spring and summer 2018). The diatoms collected in the 9 sampling stations were identified morphologically using an inverted optical microscope. A total of 10 species of the genus Rhizosolenia have been listed including: Rhizosolenia bushsolei, R alata forma alata, R bergonii, R cochlea, R hyalina, R imbricata, R setigera, R bushsolei, Rhizosolenia sp and R styliformis. The quantitative analysis of the species collected shows that the maximum cell density was recorded respectively at stations 9 and 7 located in the center of the Nador lagoon, with values of 21680 Cell/l and 15710 Cell/l. However, the minimum cell density was recorded at station 5 corresponding to Oued Bou Areg located at the edge of the lagoon with a value of 5120 Cell/l.
Classification of industrial wastewater discharged into effluent pits, an approach toward a sustainable recycling: case study of a water treatment facility in Morocco
Authors: Adam Abdeljalil , Saffaj Nabil , Mamouni Rachid
Published: January 2023

Most water treatment facilities collect industrial wastewater in separated effluent pits. This discharge strategy has been proposed by several previous research as a solution to the problems of untreated wastewater being withdrawn further into open sea or rivers, which aims to prevent the pollution of water supplies. However, this solution might also have far-reaching ecological and environmental negative consequences. In this research we have assessed the effluent’s Physico-chemical characterization over the duration of one year, utilizing a specific statistical methodology for a water treatment plant located in Morocco that used effluent pits for retaining its wastewater. Effluents collected by the water treatment plant are tested in two effluent pits to determine the effects of the direct evaporation and storage, the results of this study reveal a significant increase in the Physico-chemical characteristics of these effluents kept inside effluent pits, which may be attributed to an uptick in water pollution in case of any accidental release or spill. Regression and correlation Explanatory variables from a statistical analysis have been assessed to determine which effluent variables were indeed strongly connected to each other. Effluent recycling is proposed to minimize the likelihood of environmental and ecological concerns.
Application of eutrophication indices for assessment of the ecological quality of the Moroccan eastern Mediterranean coast: Ras Kabdana-Saïdia
Authors: Ngadi Hamza , Layachi Mostafa , Azizi Ghizlane , Belbachir Chaouki , Esseffar Sara , El Yousfi Yassine , Gueddari Hicham , Rahhou Abderrahmane , Loukili Hamza , Moumen Abdelmajid
Published: January 2023

Eutrophication of littoral seawater is estimated to be one of the main threats to marine biota. Therefore, continuous monitoring is necessary to define areas of potential risk. Our work is an essay to explore the possibility of applying the trophic state index (TRIX) to assess the state of eutrophication along the eastern coast of the Moroccan Mediterranean (Ras Kabdana-Saïdia) in concert with a number of hydro chemical parameters and nutrients descriptors aimed at selection of relevant indicators of marine coastal area ecological quality. Seawater samples were studied monthly during 2018. The following environmental parameters have been considered: temperature, salinity, pH, suspended matter, turbidity, dissolved oxygen, saturation levels, nitrite, nitrate, and orthophosphate. Principal Component Analysis was applied in order to figure out and score the most relevant combination of parameters to discriminate between sites and select representative descriptors (pressure/state) of eutrophication. The following variables are defined as relevant descriptors for classification of the sites: nutrients (N, P) and their molar ratios (N/P), the capacity of the system to produce and sustain organic matter (chlorophyll a), and the trophic state index (TRIX). The results show TRIX values below 4, the eutrophication range indicated that there is no ecological risk. The Ras Kabdana-Saïdia is located in an oligotrophic state.
Contribution to the knowledge of ecotones: impact of riverbank pollution on riparian communities in temporary environments in Eastern Morocco
Authors: Zitouni Naoual , Chavanon Guy
Published: January 2023

Riparian communities are made up of species that colonise the wet banks of different aquatic environments (ocean, river, torrent, water body, dayas) whatever their size and as long as they are being impounded. These are species that are highly dependent on their biotope, with very strict ecological and ethological requirements, and are vulnerable to any change or disturbance of the environment. Thus, depending on the type of contaminant, pollution can have different effects on this fauna: a lethal, repulsive, or attractive effect. The aim is to study the effect of pollution on the riparian community. We compare between the beetles fauna of banks of two hill dam reservoirs, one polluted and the other unpolluted. The study highlighted the attractive effect of pollution by domestic waste, particularly plastic bags, and other solid debris. Indeed, the latter, having the same physical characteristics (weight, size, thickness, etc.) as stones, leaves, and other microhabitats found in nature, have had the effect of attracting riparian species through the shelter, humidity, and shade they offer.
A variable time-step IMEX-BDF2 SAV scheme and its sharp error estimate for the Navier–Stokes equations
Authors: Di Yana , Ma Yuheng , Shen Jie , Zhang Jiwei
Published: January 2023

We generalize the implicit-explicit (IMEX) second-order backward difference (BDF2) scalar auxiliary variable (SAV) scheme for Navier–Stokes equation with periodic boundary conditions (Huang and Shen, SIAM J. Numer. Anal. 59 (2021) 2926–2954) to a variable time-step IMEX-BDF2 SAV scheme, and carry out a rigorous stability and convergence analysis. The key ingredients of our analysis are a new modified discrete Grönwall inequality, exploration of the discrete orthogonal convolution (DOC) kernels, and the unconditional stability of the proposed scheme. We derive global and local optimal H1 error estimates in 2D and 3D, respectively. Our analysis provides a theoretical support for solving Navier–Stokes equations using variable time-step IMEX-BDF2 SAV schemes. We also design an adaptive time-stepping strategy, and provide ample numerical examples to confirm the effectiveness and efficiency of our proposed methods.
Sustainable Chemical Synthesis of 2,3-Dihydrobenzofurans/1,2,3-Trisubstituted Indanes in Water by Using a Permethylated β-Cyclodextrin-Tagged N-Heterocyclic Carbene–Gold Catalyst
Authors: Morita Nobuyoshi , Krause Norbert , Chiaki Hitomi , Tanaka Kosaku , Hashimoto Yoshimitsu , Tamura Osamu
Published: January 2023

An environmentally friendly stereoselective synthesis of 2,3-dihydrobenzofurans and 1,2,3-trisubstituted indanes in water has been achieved by using a permethylated β-cyclodextrin-tagged N-heterocyclic carbene–gold complex. The gold catalyst can be recycled at least five times.
Enantioselective Synthesis of Dispirooxindole Derivatives via Asymmetric Catalytic Cascade Reactions
Authors: Hu Xiu-Qin , Xu Peng-Fei , Ma Rui , Zhang Jia-Lu
Published: January 2023

A series of optically active 3,3′-pyrrolidinyl-dispirooxindole derivatives containing a CF3 moiety have been efficiently constructed through asymmetric catalytic cascade reactions catalyzed by cinchona-derived bifunctional squaramide catalyst, bearing four contiguous stereogenic centers, two of which are vicinal spiro-stereocenters. Additionally, a wide range of substituted products were achieved with moderate to high yields (up to 99% yield) and excellent stereoselectivities (up to >20:1 dr for all cases and up to 99% ee).
Not your mother’s tape: how flexible electronics utilize adhesive technology
Authors: Shapiro Maura
Published: January 2023

The various subtypes of tape provide unique mechanisms to facilitate next-generation electronic devices
Limiting behavior of center manifolds for stochastic evolutionary equations with delay in varying phase spaces
Authors: Yang Juan , Gong Jiaxin , Wu Longyu , Shu Ji
Published: January 2023

In this article, we consider random center manifolds for a class of stochastic evolutionary equations with delay driven by multiplicative white noise. We first prove the existence and Ck smoothness of random center manifolds for the equations with delay. Then, we show the Ck smooth convergence of the center manifolds as the phase spaces approach to their singular limit.
Additive manufactured foam targets for experiments on high-power laser–matter interaction
Authors: Wiste T. , Maliuk O. , Tikhonchuk V. , Lastovicka T. , Homola J. , Chadt K. , Weber S.
Published: January 2023

Additive manufactured (AM) foams in the context of high-power laser–matter interaction have emerged as a topic of significant interest. Printed foam targets provide a highly controlled environment for laser interaction and permit a high degree of versatility in terms of average density, spatial structure, and materials. These features are of great value to a variety of applications, including inertial confinement fusion and generation of intense x-rays and gamma rays. This paper describes an approach to the design and fabrication of AM foams for laser–plasma interaction experiments, including the selection of cellular structure, optimization of mechanical properties using a finite element approach, and foam printing on dielectric and conducting substrates.
Raman spectroscopic study of the layer-dependent Davydov splitting and thermal conductivity of chemically vapor deposited two-dimensional MoSe2
Authors: Singh Vineeta , Sathe V. G. , Rath Shyama
Published: January 2023

Atomically thin MoSe2 is of interest from the perspective of estimating the layer-dependent material properties necessary for the translation of two-dimensional materials into devices. This work presents Raman spectroscopic protocols to determine a multitude of material parameters of two-dimensional MoSe2 films, including the layer thickness as well as the layer-dependent thermal conductivity, interlayer interactions, and anharmonicity. The Davydov splitting (factor-group splitting) observed in an out-of-plane A1g Raman mode, being layer-dependent in both the number and the peak positions, provides a method for estimating the number of layers. Furthermore, this work demonstrates the determination of the thermal conductivity (K) from the temperature-dependent Davydov split Raman modes of the multi-layers. The measurement of K by conventional methods is otherwise challenging for the micrometer sizes of the two-dimensional materials. The value of K thus determined increases significantly from 9 W m−1 K−1 for a four-layer thick MoSe2 film to 52 W m−1 K−1 for a monolayer. The diminishing effect of anharmonicity observed in the monolayer as compared to multi-layer MoSe2 supports the layer-dependent trend in the thermal conductivity. Overall, the findings are relevant for the applications of 2D MoSe2 in low power electronic, optoelectronic, and thermoelectric devices.
Evaluating the active site-substrate interplay between x-ray crystal structure and molecular dynamics in chorismate mutase
Authors: Summers Thomas J. , Hemmati Reza , Miller Justin E. , Agbaglo Donatus A. , Cheng Qianyi , DeYonker Nathan J.
Published: January 2023

Designing realistic quantum mechanical (QM) models of enzymes is dependent on reliably discerning and modeling residues, solvents, and cofactors important in crafting the active site microenvironment. Interatomic van der Waals contacts have previously demonstrated usefulness toward designing QM-models, but their measured values (and subsequent residue importance rankings) are expected to be influenceable by subtle changes in protein structure. Using chorismate mutase as a case study, this work examines the differences in ligand-residue interatomic contacts between an x-ray crystal structure and structures from a molecular dynamics simulation. Select structures are further analyzed using symmetry adapted perturbation theory to compute ab initio ligand-residue interaction energies. The findings of this study show that ligand-residue interatomic contacts measured for an x-ray crystal structure are not predictive of active site contacts from a sampling of molecular dynamics frames. In addition, the variability in interatomic contacts among structures is not correlated with variability in interaction energies. However, the results spotlight using interaction energies to characterize and rank residue importance in future computational enzymology workflows.
Fast electronic trapping and de-trapping by mid-gap states in CH3NH3PbCl3 single crystal
Authors: Wang Jie , Sun Yu-Qi , Shi Dong
Published: January 2023

The assumed existence of mid-gap states and their roles acting as electronic traps in lead halide perovskites are under intensive discussion. Yet, knowledge about their physical characteristics remains limited due to the lack of directly accessed optical evidence. Here, we report direct access of spectroscopic responses by mid-gap states in one prototypical metal halide perovskite, CH3NH3PbCl3 single crystal. Mid-gap electronic trapping shown by sub-gap absorption and photoluminescence quenching is demonstrated. Quenching of the inter-band photoluminescence leads to instantaneous broadening in the energetic distributions of the mid-gap, making it hard to determine the energy of each individual mid-gap state. Therefore, the subsequent mid-gap luminescence following electronic de-trapping shows largely increased spectral linewidth and varied luminescence maxima energy. Time-resolved photoluminescence revealed the fast trapping and de-trapping kinetics by mid-gap states in the CH3NH3PbCl3 single crystal. By combining existing knowledge about mid-gap states in semiconductor crystals, we define a general on-lattice surface dangling bonds scenario serving as the creation of mid-gap states in the robust CH3NH3PbCl3 single crystal.
Sc2CX (X=N2, ON, O2) MXenes as a promising anode material: A first-principles study
Authors: Özcan S. , Biel B.
Published: January 2023

MXenes’ tunable properties make them excellent candidates for many applications in future nanoelectronics. In this work, we explore the suitability of Sc2CX (X=N2, ON, O2) MXenes to act as the active anode materials in Na-ion based batteries (NIBs) by means of ab initio simulations. After analyzing the structural and elastic properties of all the possible models to evaluate the energetically favorable N and O functionalization sites, our calculations show that both Sc2CON and Sc2CN2 present a clear metallic character, making them potential candidates as anode materials. The investigation of the most relevant features for anode performance, such as the adsorption and diffusion of Na atoms, the intrinsic capacity, the open circuit voltage, and the storage capacity, shows that both systems are serious alternatives to the most common 2D materials currently employed in alkali metal batteries. In particular, Sc2CN2 presents better diffusion behavior thanks to the absence of Na clustering on its surface, with optimal diffusion barriers comparable to other 2D materials, such as MoN2, while the values of diffusion barriers for Sc2CON are at least three times smaller than those found for other anode candidates. Similarly, while the capacity of Sc2CON is close to the one reported for 2D Sc2C, Sc2CN2 possesses a power density more than twice higher than the ones of 2D materials, such as Sc2C, graphite, and MoS2. Our results, thus, confirm the urge for further experimental exploration of the MXene Sc2CX (X=N2, ON, O2) family as anode material in NIBs.
Machine learning assisted investigation of the barocaloric performance in ammonium iodide
Authors: Xu Xiong , Li Fangbiao , Niu Chang , Li Min , Wang Hui
Published: January 2023

Using the ab initio-based training database, we trained the potential function for ammonium iodide (NH4I) based on a deep neural network-based model. On the basis of this potential function, we simulated the temperature-driven β ⇒ α-phase transition of NH4I with isobaric isothermal ensemble via molecular dynamics simulations, the results of which are in good agreement with recent experimental results. As it increases near the phase transition temperature, a quarter of ionic bonds of NH4+-I− break so that NH4+ starts to rotate randomly in a disorderly manner, being able to store thermal energy without a temperature rise. It is found that NH4I possesses a giant isothermal entropy change (∼93 J K−1 kg−1) and adiabatic temperature (∼27 K) at low driving pressure (∼10 MPa). In addition, through partial substitution of I by Br in NH4I, it is found that the thermal conductivity can be remarkably improved, ascribed to the enhancement of lifetime of low frequency phonons contributed by bromine and iodine. The present work provides a method and important guidance for the future exploration and design of barocaloric material for practical applications.
Room-temperature several-hundred-of-megahertz charge sensing with single-electron resolution using a silicon transistor
Authors: Nishiguchi Katsuhiko , Yamaguchi Hiroshi , Fujiwara Akira , van der Zant Herre S. J. , Steele Gary A.
Published: January 2023

We demonstrate charge detection with single-electron resolution at high readout frequency using a silicon field-effect transistor (FET) integrated with double resonant circuits. A FET, whose channel of 10-nm width enables a single electron to be detected at room temperature, is connected to resonant circuits composed of coupled inductors and capacitors, and these double resonant circuits provide two resonance frequencies. When the FET is driven by a carrier signal at the lower resonance frequency, a small signal applied to the FET's gate modulates the resonance condition, resulting in a reflected signal appearing near the higher resonance frequency. Such operation utilizing the double resonant circuits enables charge detection with a single-electron resolution of 3 × 10−3 e/Hz0.5 and a readout frequency of 200 MHz at room temperature. In addition, a variable capacitor used in the double resonant circuits allows charge-sensing characteristics to be controlled in situ.
Probing 3D magnetic nanostructures by dark-field magneto-optical Kerr effect
Authors: Sanz-Hernández Dédalo , Skoric Luka , Cascales-Sandoval Miguel Ángel , Fernández-Pacheco Amalio
Published: January 2023

Magneto-optical techniques are key tools for the characterization of magnetic effects at a nanoscale. Here, we present the dark-field magneto-optical Kerr effect (DFMOKE), a technique we have recently developed for the characterization of three-dimensional magnetic nanostructures. We introduce the principles of DFMOKE, based on the separation of an incident beam into multiple reflected beams when focusing on a 3D nano-geometry. We show the key modifications needed in a standard focused MOKE magnetometer to perform these measurements. Finally, we showcase the power of this method by detecting the magnetic switching of a single tilted 3D nanowire, independently from the switching of a magnetic thin film that surrounds it. We obtain independent and simultaneous switching detection of the nanowire and the film for all nanowire dimensions investigated, allowing us to estimate a magnetic sensitivity of 7 × 10−15 A m2 for DFMOKE in the setup used. We conclude the article by providing perspectives of future avenues where DFMOKE can be a very powerful characterization tool in the future investigations of 3D magnetic nanostructures.
Locomotion of a micro-swimmer towing load through shear-dependent non-Newtonian fluids
Authors: Ouyang Zhenyu , Liu Chen , Qi Tingting , Lin Jianzhong , Ku Xiaoke
Published: January 2023

This paper simulates the locomotion of a micro-swimmer towing cargo through a shear-dependent non-Newtonian fluid. We investigate the effect of the shear-dependent rheology (refers to the power-law index n), swimming Reynolds numbers (Re), and the relative position (refers to the distance ds and the concerning angle θ) between the swimmer and the cargoes on the assemblies' locomotion. For a swimmer towing a cargo, we find that a cargo-puller, cargo-pusher, or pusher-cargo (three typical towing models) swims faster in the shear-thickening fluids than in the shear-thinning fluids at Re ≤ 1. Moreover, the pusher-cargo swims significantly faster than the counterpart puller-cargo at Re ≤ 1. For a swimmer towing two cargoes, we find that the maximum negative swimming speeds can be achieved at θ = 30° and 150°, corresponding to two typical regular-triangle structures assembled by the squirmer and the cargoes. Interestingly, some regular-triangle assemblies (puller with θ = 30° and pusher with θ = 150°) can maintain a swimming opposite to their initial orientation. In addition, we obtain a relation of energy expenditure P ∼ Ren−1; it is also found that the assembly swimming in the shear-thinning fluids is more efficient than in the shear-thickening ones. Our results provide specified guidance in the designing of cargo-carrying micro-swimming devices.
Machine learning matrix product state ansatz for strongly correlated systems
Authors: Ghosh Sumanta K. , Ghosh Debashree
Published: January 2023

Machine learning (ML) has been used to optimize the matrix product state (MPS) ansatz for the wavefunction of strongly correlated systems. The ML optimization of MPS has been tested for the Heisenberg Hamiltonian on one-dimensional and ladder lattices, which correspond to conjugated molecular systems. The input descriptors and output for the supervised ML are lattice configurations and configuration interaction coefficients, respectively. Efficient learning can be achieved from data over the full Hilbert space via exact diagonalization or full configuration interaction, as well as over a much smaller sub-space via Monte Carlo Configuration Interaction. We show that this circumvents the need to calculate energy and operator expectation values and is therefore a computationally efficient alternative to variational optimization.
Perspective on highly twisted artificial muscles
Authors: Lamuta Caterina
Published: January 2023

Lightweight and single-component artificial muscles represent a promising alternative to conventional actuators for several applications requiring a large power/weight ratio, including modern soft and assistive robotics. Highly Twisted Artificial Muscles (HTAMs) are a relatively young category of artificial muscles, introduced only in 2011. Considering their young age, there is still a lack of awareness in the scientific community on what has been accomplished so far in this field and what are current challenges and limitations. This Perspective paper aims to provide an extensive overview in terms of working mechanism, manufacturing, modeling, and applications of different types of HTAMs. A discussion on challenges and future directions is then provided to encourage transformative research on this topic.
Numerical investigation of solitary wave breaking over a slope based on multi-phase smoothed particle hydrodynamics
Authors: He Fang , Zhang Yifan , Jiang Haonan , Huang Can
Published: January 2023

This study presents a numerical investigation of the solitary wave breaking over a slope by using the multi-phase smoothed particle hydrodynamics (SPH) method. Four different computational models are proposed to solve the gas-related far-field boundary conditions, and the model with the least disturbance to the internal flow field is selected. Since the artificial viscous coefficient can greatly affect the wave-breaking location, an empirical equation is fitted to quickly determine the optimal value of the artificial viscous coefficient. In addition, the turbulence model and three-dimensional effect on the wave breaking are discussed in this study. The results show that the present two-dimensional multi-phase SPH without a turbulence model can capture the macroscopic characteristics of the flow before the vortices convert to three dimensional flow structures caused by the wave breaking. Then, the processes of shoaling solitary wave breaking with different slopes and relative wave heights are simulated. Compared with the single-phase SPH, the multi-phase SPH is of great help in improving the prediction of wave breaking. A vortex similar to the Rankine Vortex is observed near the wave crest. Its intensity affects the pressure distribution of the gas, and its relative position to the wave crest is relevant to the energy transfer from the water to the gas. During the solitary wave propagating from deep water to shallow water, energy dissipation of gas and water shows four different stages. In the stage of energy dissipation, the gas can absorb the great energy from the water, which effectively dissipates the wave energy.
Interfacial bonding between iron and Mo- and Cr-doped tungsten carbides
Authors: Aghdasi P. , Li D. Y.
Published: January 2023

Doping or partially substituting WC with metals, e.g., Mo and Cr, can lower its density while keeping the strength of the modified carbides similar to that of WC, making them attractive as the reinforcement for hardfacing overlays and tool steels, since they can be distributed homogeneously in the metal matrix. However, it is unclear if the doped WC has desirable interfacial bonding with the matrix, e.g., iron. In this study, we investigated the interfacial bonding of Mo- and Cr-doped WC, compared to that of mono-WC, with austenite and ferrite irons via first-principles calculations. (112¯0)Carbide//(110)Fe, (101¯0)Carbide//(100)Fe, and (0001)Carbide//(100)Fe interfaces for both ferrite and austenite with the lowest interfacial mismatch were investigated. Characteristics of the formed interfacial bonds were studied based on the electron localization function, electronic density of states, bond order, and net charge. It was demonstrated that the Mo and Cr-doped WC carbides, (W4−x, M)C4, show comparable or higher adhesive work with iron, compared to that of mono-WC with iron. The metal-substituted or doped W4C4 carbides are promising replacements of heavier WC for tool steels and ferrous hardfacing overlays.
Fidelity of counting the transferred electrons in a GaAs-based monolithic single-electron pump and transistor system with a charge-lock feedback circuit
Authors: Ghee Young-Seok , Kim Bum-Kyu , Park Suk-In , Song Jindong , Kim Wan-Seop , Bae Myung-Ho , Kim Nam
Published: January 2023

We developed an electron-counting technique for a self-referenced single-electron quantized current source of a single-electron-pump system and investigated the fidelity of our whole measurement process, including single-electron pumping and electron counting by a single-electron transistor (SET) with a charge-lock feedback loop. The device was fabricated monolithically using a two-dimensional electron system of a GaAs/AlGaAs hetero-junction. In addition to the probability of single-electron transfer, we also measured the current noise spectrum of the SET, from which its charge noise power Sq was derived. The results show that the estimated charge noise of 2.2 ×10−4 e/Hz for a semiconductor-based SET is comparable to that of metallic SETs.
Comparative tongue anatomy of the rakali (Hydromys chrysogaster) and greater stick-nest rat (Leporillus conditor) (Rodentia; Muridae)
Authors: Humphries Alexia , Seow Bernadette , Danee Shriya , Ness Bastian , Warburton Natalie Marina
Published: January 2023

For many mammals, the tongue provides an important functional interface with the environment through roles including manipulating, ingesting, and mechanically processing food items. As such, the adaptations of the tongue reflect different physical properties of an animal’s diet. We sought to investigate whether adaptations of the tongue are apparent in two native Australian rodents that have divergent dietary niches: the semiaquatic and mixed feeding rakali (Hydromys chrysogaster) and the arid dwelling, herbivorous stick-nest rat (Leporillus conditor). Both species retained many lingual features typical of rodents. A notable difference was a large, annular pad surrounding the single circumvallate papilla in H. chrysogaster, suggesting an enhanced gustatory function, which would be consistent with adaptation to a semiaquatic, mixed diet. In contrast, L. conditor appeared to have reduced gustatory sensitivity and mechanical dexterity, consistent with crushing their preferred succulent plant forage and manipulating sticks for nest building. The descriptions provide a novel view of the evolution of soft tissues within Australian endemic rodents.
Chronic non-cancer pain management – insights from Australian general practitioners: a qualitative descriptive study
Authors: Gilkes Lucy , Bulsara Caroline , Mavaddat Nahal
Published: January 2023

Background The study explored the experiences and perceptions of GPs regarding the management of chronic non-cancer pain (CNCP). Specifically, participants were asked to identify perceived enablers and barriers to CNCP care and how the care of patients with CNCP may be improved. Methods The study utilised a qualitative descriptive methodology. General practice in Western Australia. The sample was purposive with 12 Australian GPs from predominantly metropolitan locations and with experience in managing CNCP. Semi structured interviews were conducted. Each interview was of 45–60 min duration. All interviews were audio recorded and transcribed using a secure transcription service. Thematic analysis developed themes inductively and deductively. Results Themes emerged regarding: the importance of a holistic and personalised approach; the important role of a coordinating GP; the need for an evidence-based approach to opioid management; concerns relating to access to multidisciplinary services; the importance of clinician and patient education regarding CNCP; and an acknowledgement of the challenges for doctors and patients in managing CNCP. Conclusions Currently, the management of CNCP in Australia is challenging. Notable challenges include: difficulties with continuity of patient care; challenges with patient expectations of treatment, in particular opioid medications; difficulty with access to the health services required to enable holistic care; and the need for improved pain education in the community. The breadth of these challenges suggests there is a need for supportive organisational and structural considerations in the healthcare system to enable optimal care of CNCP in the community.
Antidepressants can induce mutation and enhance persistence toward multiple antibiotics
Authors: Wang Yue , Yu Zhigang , Ding Pengbo , Lu Ji , Mao Likai , Ngiam Lyman , Yuan Zhiguo , Engelstädter Jan , Schembri Mark A. , Guo Jianhua
Published: January 2023

Antibiotic resistance is an urgent threat to global health. Antidepressants are consumed in large quantities, with a similar pharmaceutical market share (4.8%) to antibiotics (5%). While antibiotics are acknowledged as the major driver of increasing antibiotic resistance, little attention is paid to the contribution of antidepressants in this process. Here, we demonstrate that antidepressants at clinically relevant concentrations induce resistance to multiple antibiotics, even following short periods of exposure. Antibiotic persistence was also enhanced. Phenotypic and genotypic analyses revealed the enhanced production of reactive oxygen species following exposure to antidepressants was directly associated with increased resistance. An enhanced stress signature response and stimulation of efflux pump expression were also associated with increased resistance and persistence. Mathematical modeling also predicted that antidepressants would accelerate the emergence of antibiotic-resistant bacteria, and persister cells would help to maintain the resistance. Overall, our findings highlight the antibiotic resistance risk caused by antidepressants.
Charge transfer as a mechanism for chlorophyll fluorescence concentration quenching
Authors: Bourne-Worster Susannah , Feighan Oliver , Manby Frederick R.
Published: January 2023

Highly concentrated solutions of chlorophyll display rapid fluorescence quenching. The same devastating energy loss is not seen in photosynthetic light-harvesting antenna complexes, despite the need for chromophores to be in close proximity to facilitate energy transfer. A promising, though unconfirmed mechanism for the observed quenching is energy transfer from an excited chlorophyll monomer to a closely associated chlorophyll pair that subsequently undergoes rapid nonradiative decay to the ground state via a short-lived intermediate charge-transfer state. In this work, we make use of newly emerging fast methods in quantum chemistry to assess the feasibility of this proposed mechanism. We calculate rate constants for the initial charge separation, based on Marcus free-energy surfaces extracted from molecular dynamics simulations of solvated chlorophyll pairs, demonstrating that this pathway will compete with fluorescence (i.e., drive quenching) at experimentally measured quenching concentrations. We show that the rate of charge separation is highly sensitive to interchlorophyll distance and the relative orientations of chromophores within a quenching pair. We discuss possible solvent effects on the rate of charge separation (and consequently the degree of quenching), using the light-harvesting complex II (LH2) protein from
rps. acidophila
as a specific example of how this process might be controlled in a protein environment. Crucially, we reveal that the LH2 antenna protein prevents quenching, even at the high chlorophyll concentrations required for efficient energy transfer, by restricting the range of orientations that neighboring chlorophyll pairs can adopt.
Role of
Pfs47
in the dispersal of ancestral
Plasmodium falciparum
malaria through adaptation to different anopheline vectors
Authors: Molina-Cruz Alvaro , Canepa Gaspar E. , Dwivedi Ankit , Liu Weimin , Raytselis Nadia , Antonio-Nkondjio Christophe , Hahn Beatrice H. , Silva Joana C. , Barillas-Mury Carolina
Published: January 2023

Plasmodium falciparum
malaria originated when
Plasmodium praefalciparum
, a gorilla malaria parasite transmitted by African sylvan anopheline mosquitoes, adapted to humans. Pfs47, a protein on the parasite surface mediates
P. falciparum
evasion of the mosquito immune system by interacting with a midgut receptor and is critical for
Plasmodium
adaptation to different anopheline species. Genetic analysis of 4,971
Pfs47
gene sequences from different continents revealed that Asia and Papua New Guinea harbor
Pfs47
haplotypes more similar to its ortholog in
P. praefalciparum
at sites that determine vector compatibility, suggesting that ancestral
P. falciparum
readily adapted to Asian vectors. Consistent with this observation, Pfs47-receptor gene sequences from African sylvan malaria vectors, such as
Anopheles moucheti
and
An. marshallii
, were found to share greater similarity with those of
Asian
vectors than those of vectors of the African
An. gambiae
complex. Furthermore, experimental infections provide direct evidence that transformed
P. falciparum
parasites carrying
Pfs47
orthologs of
P. praefalciparum
or
P. reichenowi
were more effective at evading the immune system of the Asian malaria vector
An. dirus
than
An. gambiae
. We propose that high compatibility of ancestral
P. falciparum
Pfs47 with the receptors of Asian vectors facilitated the early dispersal of human malaria to the Asian continent, without having to first adapt to sub-Saharan vectors of the
An. gambiae
complex.