bluuebunny/crossref_metadata_2025 huggingface dataset:
Doppler ultrasound in pregnancy – quality requirements of DEGUM and clinical application (part 2)
Authors: Faber Renaldo , Heling Kai-Sven , Steiner Horst , Gembruch Ulrich
Published: April 2021

This second part on Doppler sonography in prenatal medicine and obstetrics reviews its clinical applications. While this has not become the initially anticipated screening tool, it is used for the diagnosis and surveillance of a variety of fetal pathologies. For example, the sonography-based determination of uterine artery blood flow indices is an important parameter for the first trimester multimodal preeclampsia risk assessment, increasing accuracy and providing indication for the prophylactic treatment with aspirin. It also has significant implications for the diagnosis and surveillance of growth-restricted fetuses in the second and third trimesters through Doppler-sonographic analysis of umbilical artery, middle cerebral artery and ductus venosus. Here, especially the hemodynamics of the ductus venosus provides a critical criterium for birth management of severe, early-onset FGR before 34 + 0 weeks of gestation. Further, determination of maximum blood flow velocity of the middle cerebral artery is a central parameter in fetal diagnosis of anemia which has been significantly improved by this analysis. However, it is important to note that the mentioned improvements can only be achieved through highest methodological quality. Importantly, all these analyses are also applied to twins and higher order multiples. Here, for the differential diagnosis of specific complications such as TTTS, TAPS and TRAP, the application of Doppler sonography has become indispensable. To conclude, the successful application of Doppler sonography requires both exact methodology and precise pathophysiological interpretation of the data.
Microbial Biotransformation of Cannabidiol (CBD) from Cannabis sativa
Authors: Ahmed Safwat A. , Ibrahim Amany K. , Radwan Mohamed M. , Slade Desmond , Chandra Suman , Khan Ikhlas A. , ElSohly Mahmoud A.
Published: April 2021

Microbial biotransformation of cannabidiol was assessed using 31 different microorganisms. Only Mucor ramannianus (ATCC 9628), Beauveria bassiana (ATCC 7195), and Absidia glauca (ATCC 22 752) were able to metabolize cannabidiol. M. ramannianus (ATCC 9628) yielded five metabolites, namely, 7,4″β-dihydroxycannabidiol (1), 6β,4″β-dihydroxycannabidiol (2), 6β,2″β-dihydroxycannabidiol (3), 6β,3″α-dihydroxycannabidiol (4), and 6β,7,4″β-trihydroxycannabidiol (5). B. bassiana (ATCC 7195) metabolized cannabidiol to afford six metabolites identified as 7,3″-dihydroxycannabidivarin (6), 7-hydroxycannabidivarin-3″-carboxylic acid (7), 3″-hydroxycannabidivarin (8), 4″β-hydroxycannabidiol (9), and cannabidivarin-3″-carboxylic acid (10) along with compound 1. Incubation of cannabidiol with A. glauca (ATCC 22 752) yielded three metabolites, 6α,3″-dihyroxycannabidivarin (11), 6β,3″-dihyroxycannabidivarin (12), and compound 6. All compounds were evaluated for their antimicrobial and antiprotozoal activity.
Heiminfusionstherapie bei Morbus Pompe: Konsensusempfehlungen für den deutschsprachigen Raum
Authors: Hahn Andreas , Lampe Christina , Boentert Matthias , Hundsberger Thomas , Löscher Wolfgang , Wenninger Stephan , Ziegler Andreas , Lagler Florian , Ballhausen Diana , Schlegel Thomas , Schoser Benedikt
Published: April 2021

Hintergrund Der Morbus Pompe ist eine lysosomale Multisystemerkrankung mit prädominanter Myopathie, für die eine Enzymersatztherapie (EET) mit rekombinanter α-Glucosidase verfügbar ist. Diese muss aktuell zweiwöchentlich lebenslang erfolgen. Um die Belastung durch diese Behandlungsform gering zu halten, besteht bei vielen Betroffenen der Wunsch, die EET zu Hause als sog. Heiminfusionstherapie durchzuführen.

Ziele und Methoden Im Rahmen zweier Deutsch-Österreichisch-Schweizerischer Konsensus-Expertentreffen in den Jahren 2019 und 2020 wurde diskutiert, welche Voraussetzungen gegeben sein müssen, damit eine Heiminfusionstherapie medizinisch vertretbar erfolgen kann, wie diese sachgemäß durchzuführen ist und wie die Rechtslage für delegierende Ärzte aussieht.

Ergebnisse und Diskussion Prinzipiell ist bei Patienten mit Morbus Pompe eine Heiminfusionstherapie möglich, wenn bestimmte Voraussetzungen erfüllt sind. Die Entscheidung muss für jeden Patienten individuell getroffen werden. Der behandelnde Arzt delegiert die Durchführung der Heiminfusionstherapie ad personam an eine Pflegekraft. Die Endverantwortung für die korrekte Durchführung der EET verbleibt aber beim Arzt. Die Heiminfusionstherapie muss durch speziell geschultes Pflegepersonal erfolgen. Hauptrisiko ist das Auftreten allergischer Reaktionen. Deren adäquate Erstbehandlung muss ebenso sichergestellt sein wie die Verfügbarkeit einer notfallmedizinischen Versorgung. Um die psychosoziale Belastung von Patienten mit Morbus Pompe in deutschsprachigen Ländern zu minimieren und delegierenden Ärzten größere Rechtssicherheit zu geben, sind klarere Regelungen für die Durchführung einer Heiminfusionstherapie wünschenswert.
InspirerMundi—Remote Monitoring of Inhaled Medication Adherence through Objective Verification Based on Combined Image Processing Techniques
Authors: Vieira-Marques Pedro , Almeida Rute , Teixeira João F. , Valente José , Jácome Cristina , Cachim Afonso , Guedes Rui , Pereira Ana , Jacinto Tiago , Fonseca João A.
Published: April 2021

Background The adherence to inhaled controller medications is of critical importance for achieving good clinical results in patients with chronic respiratory diseases. Self-management strategies can result in improved health outcomes and reduce unscheduled care and improve disease control. However, adherence assessment suffers from difficulties on attaining a high grade of trustworthiness given that patient self-reports of high-adherence rates are known to be unreliable.

Objective Aiming to increase patient adherence to medication and allow for remote monitoring by health professionals, a mobile gamified application was developed where a therapeutic plan provides insight for creating a patient-oriented self-management system. To allow a reliable adherence measurement, the application includes a novel approach for objective verification of inhaler usage based on real-time video capture of the inhaler's dosage counters.

Methods This approach uses template matching image processing techniques, an off-the-shelf machine learning framework, and was developed to be reusable within other applications. The proposed approach was validated by 24 participants with a set of 12 inhalers models.

Results Performed tests resulted in the correct value identification for the dosage counter in 79% of the registration events with all inhalers and over 90% for the three most widely used inhalers in Portugal. These results show the potential of exploring mobile-embedded capabilities for acquiring additional evidence regarding inhaler adherence.

Conclusion This system helps to bridge the gap between the patient and the health professional. By empowering the first with a tool for disease self-management and medication adherence and providing the later with additional relevant data, it paves the way to a better-informed disease management decision.
Magnetooscillations of temperature and microwave absorption in a highly correlated 2D electron gas on liquid helium
Authors: Monarkha Yu. P.
Published: April 2021

The Coulombic effect on microwave-induced electron heating in a 2D electron gas on liquid helium under quantizing magnetic field is theoretically studied. An extension of the linewidth of the intersubband resonance which takes into account squeezing of the electron density of states into Landau levels and strong internal electric fields of fluctuational origin is proposed. This approximation results in two-hump peaks of electron temperature and power absorption near certain values of the magnetic field. For low electron densities, the asymmetry of the two-hump peaks of power absorption is shown to be opposite to the asymmetry of electron temperature peaks, which explains experimental observations. The importance of two-ripplon emission processes for the description of subband occupancies and the energy relaxation rate was demonstrated.
Frustration effect on escape rate in Josephson junctions between single-band and three-band superconductors in the macroscopic quantum tunneling regime
Authors: Askerzade I. N. , Aydin A.
Published: April 2021

The escape rate of S → R switching (from superconducting S state to resistive R state) in Josephson junction formed by s-wave single-band (SB) and three-band (ThB) superconductors (SB/ThB junctions) in macroscopic quantum tunneling regime is investigated. We use the effective critical current approximation in SB/ThB junctions. It was shown that escape rate can exhibit qualitative features in the case of frustration effects in ThB superconductors. Inclusion of Leggett modes in ThB superconductors leads to enhancement of escape rate in three-channel Josephson junction in comparison with single-channel junctions.
Coronene-uracil complexes embedded in argon matrices: FTIR spectroscopy and quantum-mechanical calculations
Authors: Stepanian S. G. , Ivanov A. Yu. , Karachevtsev V. A. , Adamowicz L.
Published: April 2021

We employ low-temperature matrix-isolation FTIR spectroscopy and quantum chemical calculations to study the interaction between nucleobase uracil and coronene which models the graphene surface. To observe the dimer FTIR spectrum, we use a quartz microbalance that allows us to produce matrix samples with precisely determined concentrations of coronene and uracil (with the concentration ratio of 2.5:1:1000 for coronene:uracil:argon). The interaction between coronene and uracil results in spectral shifts of uracil spectral bands. These shifts do not exceed 10 cm−1. The maximum shifts are observed for the C=O stretching and NH out-of-plane vibrations of uracil. The structures and interaction energies of stacked and H-bonded coronene-uracil complexes are calculated at the DFT/B3LYP(GD3BJ)/aug-cc-pVDZ and MP2/aug-cc-pVDZ levels of theory. In total, 19 stable stacked and two H-bonded coronene-uracil dimer structures are found in the calculations. The interaction energy obtained for the most stable stacked dimer is −12.1 and −14.3 kcal/mol at the DFT and MP2 levels, respectively. The interaction energies of the H-bonded dimers do not exceed − 3 kcal/mol. The IR spectra of the studied monomeric molecules and of all the dimers are calculated at the DFT/B3LYP(GD3BJ)/aug-cc-pVDZ level of theory. The spectral shifts of the most stable stacked coronene-uracil dimer obtained in the calculations are in good agreement with the experimental results.
Fluctuations of linear eigenvalue statistics of reverse circulant and symmetric circulant matrices with independent entries
Authors: Maurya Shambhu Nath , Saha Koushik
Published: April 2021

In this article, we study the fluctuations of linear eigenvalue statistics of reverse circulant (RCn) and symmetric circulant (SCn) matrices with independent entries that satisfy some moment conditions. We show that 1nTrϕ(RCn) and 1nTrϕ(SCn) obey the central limit theorem type result, where ϕ is a polynomial test function.
Two decades of terahertz cross-correlation spectroscopy
Authors: Molter D. , Klier J. , Weber S. , Kolano M. , Jonuscheit J. , von Freymann G.
Published: April 2021

Terahertz cross-correlation spectroscopy enables phase-sensitive measurements without the need for a laser source and, hence, presents a cost-efficient and versatile alternative to common terahertz time-domain spectroscopy approaches. This review article presents the development of this technique over the past two decades as well as applications of this approach. It is completed by a detailed mathematical description proving the irrelevance of the optical phases of the employed pump light modes. Numerical investigations of the resulting signal demonstrate the applicability and are compared to state-of-the-art measurements. Terahertz cross-correlation spectroscopy is a valuable alternative for moderate-demand applications already. Further possible improvements are discussed.
Line-of-sight and non-line-of-sight links for dispersive terahertz wireless networks
Authors: Ghasempour Yasaman , Amarasinghe Yasith , Yeh Chia-Yi , Knightly Edward , Mittleman Daniel M.
Published: April 2021

Despite the rapidly growing interest in exploiting millimeter and terahertz waves for wireless data transfer, the role of reflected non-line-of-sight (NLOS) paths in wireless networking is one of the least explored questions. In this paper, we investigate the idea of harnessing these specular NLOS paths for communication in directional networks at frequencies above 100 GHz. We explore several illustrative transmitter architectures, namely, a conventional substrate-lens dipole antenna and a leaky-wave antenna. We investigate how these high-gain directional antennas offer both new challenges and new opportunities for exploiting NLOS paths. Our results demonstrate the sensitivity to antenna alignment, power spectrum variations, and the disparity in supported bandwidth of various line-of-sight (LOS) and reflected path configurations. We show that NLOS paths can, under certain circumstances, offer even higher data rates than the conventional LOS path. This result illustrates the unique opportunities that distinguish THz wireless systems from those that operate at lower frequencies.
Ion cyclotron parametric turbulence and anomalous convective transport of the inhomogeneous plasma in front of the fast wave antenna
Authors: Mikhailenko V. S. , Mikhailenko V. V. , Lee Hae June
Published: April 2021

The theory of the ion cyclotron (IC) electrostatic parametric instabilities of the inhomogeneous plasma that are driven by the inhomogeneous electric field of the fast wave (FW) in front of FW antenna is developed. It is found that the spatial inhomogeneity of the parametric IC turbulence and of the drift turbulence is at the origin of the flows that transport a large part of FW power, deposited to the pedestal plasma, to the scrape-off layer and later to the divertor mostly along field lines.
Cognitive simulation models for inertial confinement fusion: Combining simulation and experimental data
Authors: Humbird K. D. , Peterson J. L. , Salmonson J. , Spears B. K.
Published: April 2021

The design space for inertial confinement fusion (ICF) experiments is vast, and experiments are extremely expensive. Researchers rely heavily on computer simulations to explore the design space in search of high-performing implosions. However, ICF multiphysics codes must make simplifying assumptions, and thus deviate from experimental measurements for complex implosions. For more effective design and investigation, simulations require input from past experimental data to better predict future performance. In this work, we describe a cognitive simulation method for combining simulation and experimental data into a common, predictive model. This method leverages a machine learning technique called “transfer learning,” the process of taking a model trained to solve one task, and partially retraining it on a sparse dataset to solve a different, but related task. In the context of ICF design, neural network models are trained on large simulation databases and partially retrained on experimental data, producing models that are far more accurate than simulations alone. We demonstrate improved model performance for a range of ICF experiments at the National Ignition Facility and predict the outcome of recent experiments with less than 10% error for several key observables. We discuss how the methods might be used to carry out a data-driven experimental campaign to optimize performance, illustrating the key product—models that become increasingly accurate as data are acquired.
Development of highly sensitive fiber-optic acoustic sensor and its preliminary application for sound source localization
Authors: Wu Gaomi , Xiong Linsen , Dong Zhifei , Liu Xin , Cai Chen , Qi Zhi-mei
Published: April 2021

A metal diaphragm-based omnidirectional fiber-optic acoustic sensor with high sensitivity has been developed in this work. The acousto-optic transducer of the sensor is a single-wavelength extrinsic Fabry–Pérot interferometer (EFPI) that is highly sensitive to the displacement of the diaphragm’s center. The sensor can stably work in the linear response region of the EFPI in a wide range of temperature from −20 to 60 °C. The pressure sensitivity of the sensor is larger than 800 mV/Pa, and the sensitivity fluctuation in the frequency range from 100 Hz to 6 kHz is smaller than 3 dB. The noise-limited minimum detectable pressure obtained at 1 kHz of the sensor is 126 μPa/Hz1/2. In addition, the above-prepared fiber-optic acoustic sensors present excellent phase consistency with each other, which facilitates the formation of a sensor array for sound source localization. In this work, a cross-shaped fiber-optic sensor array was prepared and then used to detect and track a small drone flying in the field. The experimental results show that the sensor array can capture the acoustic fingerprint of the drone at a distance as far as 300 m. This detection distance is more than ten times longer than that of a conventional electret condenser microphone. The azimuth angle of the drone obtained with the fiber-optic acoustic sensor array has a deviation of smaller than 10° relative to the GPS data from the drone.
Growth evolution of polar-plane-free faceted GaN structures on (112¯2) and (1¯1¯22¯) GaN substrates
Authors: Matsuda Yoshinobu , Funato Mitsuru , Kawakami Yoichi
Published: April 2021

We compare the growth evolution of polar-plane-free faceted GaN structures on (112¯2) and (1¯1¯22¯) planes. The crystal morphologies of the three-dimensional (3D) GaN structures depend on surface orientations. To discuss the underlying mechanism, the temporal developments of the cross-sectional shapes during growth are visualized by periodically inserting AlGaN markers. Quantitative analyses using these markers reveal that as the growth proceeds, the growth rates of the top and inclined facets of the 3D GaN on (112¯2) monotonically decrease, whereas those of the 3D GaN on (1¯1¯22¯) monotonically increase. The opposite tendencies are attributed to the difference in the surface diffusion of adatoms between the top and inclined facets. Furthermore, it is suggested that the surface bond configuration of each crystallographic plane strongly affects the adatom migration, resulting in distinct 3D GaN morphologies on (112¯2) and (1¯1¯22¯).
Voltage control of skyrmions: Creation, annihilation, and zero-magnetic field stabilization
Authors: Zhou Yifan , Mansell Rhodri , van Dijken Sebastiaan
Published: April 2021

Voltage manipulation of skyrmions is a promising path toward low-energy spintronic devices. Here, voltage effects on skyrmions in a GdOx/Gd/Co/Pt heterostructure are observed experimentally. The results show that the skyrmion density can be both enhanced and depleted by the application of an electric field, along with the ability, at certain magnetic fields to completely switch the skyrmion state on and off. Further, a zero magnetic field skyrmion state can be stabilized at a negative bias voltage using a defined voltage and magnetic field sequence. The voltage effects measured here occur on a few-second timescale, suggesting an origin in voltage-controlled magnetic anisotropy rather than ionic effects. By investigating the skyrmion nucleation rate as a function of temperature, we extract the energy barrier to skyrmion nucleation in our sample. Further, micromagnetic simulations are used to explore the effect of changing the anisotropy and Dzyaloshinskii–Moriya interaction on skyrmion density. Our work demonstrates the control of skyrmions by voltages, showing functionalities desirable for commercial devices.
Kinetic theory models for granular mixtures with unequal granular temperature: Hydrodynamic velocity
Authors: Solsvik Jannike , Manger Eirik
Published: April 2021

Kinetic theory for granular mixtures with a separate granular temperature for each solid phase is considered. The particle phases are assumed to follow a Maxwellian distribution with zero-order approximation of the Boltzmann equation. A solution strategy for solving the integrals of the collisional closure relations is presented. The present analysis enables the solution of these integrals without neglecting the solid particle hydrodynamic velocities in the distribution function. However, the solution strategy limits the validity of the closure relations to relatively small and moderate hydrodynamic velocity differences. Dependent on the magnitude of the hydrodynamic velocity difference, the present closure relations can differ significantly from the simplified models where such velocity difference is traditionally neglected.
Capping and gate control of anomalous Hall effect and hump structure in ultra-thin SrRuO3 films
Authors: Kim Donghan , Sohn Byungmin , Kim Minsoo , Hahn Sungsoo , Kim Youngdo , Kim Jong Hyuk , Choi Young Jai , Kim Changyoung
Published: April 2021

Ferromagnetism and exotic topological structures in SrRuO3 (SRO) induce sign-changing anomalous Hall effect (AHE). Recently, hump structures have been reported in the Hall resistivity of SRO thin films, especially in the ultra-thin regime. We investigate the AHE and hump structure in the Hall resistivity of SRO ultra-thin films with an SrTiO3 (STO) capping layer and ionic liquid gating. STO capping results in sign changes in the AHE and modulation of the hump structure. In particular, the hump structure in the Hall resistivity is strongly modulated and even vanishes in STO-capped 4 unit cell films. In addition, the conductivity of STO-capped SRO ultra-thin films is greatly enhanced with restored ferromagnetism. We also performed ionic liquid gating to modulate the electric field at SRO/STO interface. Drastic changes in the AHE and hump structure are observed with different gate voltages. Our study shows that the hump structure as well as the AHE can be controlled by tuning inversion symmetry and the electric field at the interface.
Generation of superstrong quasi-stationary magnetic fields in laser cluster plasma
Authors: Andreev A.A. , Platonov K.Yu.
Published: April 2021

An analytical model has been developed for the generation of a superstrong quasi-stationary magnetic field (up to several GG) in the focal waist of an ultra-intense short circularly polarised laser pulse interacting with a gas-cluster target. The rotation of relativistic electrons around the ionised core of the cluster has been shown to produce a magnetic moment and a quasi-stationary magnetic field. With a large number of nanoclusters, the magnetic field occupies the entire focal volume with a characteristic spatial scale of tens of micrometers and exists during the cluster expansion time (i.e., several picoseconds).
Broadband (100 kHz – 100 MHz) ultrasound PVDF detectors for raster-scan optoacoustic angiography with acoustic resolution
Authors: Kurnikov A.A. , Pavlova K.G. , Orlova A.G. , Khilov A.V. , Perekatova V.V. , Kovalchuk A.V. , Subochev P.V.
Published: April 2021

Spherical ultrasonic antennas are used in raster-scan optoacoustic (OA) angiography to record broadband signals generated by haemoglobin molecules in blood when they absorb pulsed optical radiation. Depending on the size of haemoglobin-containing structures, the characteristic frequencies of OA signals can vary quite significantly, ranging from hundreds of kilohertz to hundreds of megahertz. Meanwhile, the bandwidth of the receiving frequency band of standard piezoelectric sensors, as a rule, does not exceed the centre frequency value. It is possible to expand the receiving band of ultrasonic detectors to the required 0.1 kHz – 100 MHz values by using nonresonant piezomaterials based on polyvinidylene fluoride (PVDF). Two ultra-wideband detectors based on PVDF piezofilms of different thicknesses (9 μm and 25 μm) with different amplitude-frequency characteristics are experimentally compared. Comparative OA imaging of a tissue-like phantom demonstrates that the low-frequency sensor (film thickness l = 25 μm) has a greater depth of field, while the high-frequency sensor (l = 9 μm) has a better sensitivity in the range of 40 – 100 MHz. Using OA imaging of an experimental tumour in vivo, it is shown that a sensor with l = 25 μm is better suited for examining normal tissue containing relatively large blood vessels, while a sensor with l = 9 μm is better suited for studying tumour tissue containing a large number of multidirectional blood vessels of minimal size comparable to the maximum spatial resolution of the OA system.
Diode laser generating 3-ns pulses for a high resolution lidar
Authors: Pershin S.M. , Grishin M.Ya. , Zavozin V.A. , Makarov V.S. , Lednev V.N. , Fedorov A.N. , Myasnikov A.V. , Turin A.V.
Published: April 2021

An AlGaAs laser (907 nm, 0.2 μJ) with a 3-ns pulse duration and eye-safe energy density below 1 μJ cm−2 is developed for lidar application. The laser is composed of three stacked diodes in a plastic housing. An external pump current generator based on discrete elements with an FMMT417 bipolar transistor switch is assembled on a printed circuit board together with the laser. A lidar based on this laser and a single photon avalanche diode (SPAD) as a detector is used to monitor aerosols with a resolution of 10 cm inside the tunnel of the Baksan Neutrino Observatory near the Elbrus volcano. An abrupt three-fold increase in aerosol emanation of yet unknown nature is recorded for the first time. The absence of the Earth’s crust disturbance traces in the signal of a laser interferometer with a resolution of 1.6 × 10−11 m testifies to a high sensitivity of the lidar for monitoring geodynamic processes.
Reconstruction of fluorophore concentration distribution in diffuse fluorescence tomography based on Tikhonov regularisation and nonnegativity condition
Authors: Fiks I.I. , Turchin I.V.
Published: April 2021

We propose to solve the inverse problem of diffuse fluorescence tomography (DFT) – reconstruction of the spatial distribution of the fluorophore in biological tissues – by a method based on Tikhonov regularisation with the nonnegativity condition (TRNC) of the reconstructed components of the solution vector. Model experiments on a biotissue phantom demonstrate that the TRNC method allows for a more accurate reconstruction of the distribution of the fluorophore concentration, and is also more stable in comparison with the known algorithms used in DFT, such as ART, SMART, NNLS, etc.
Updating the Australian digital soil texture mapping (Part 1
Authors: Malone Brendan , Searle Ross
Published: April 2021

Soil texture (% sand, silt and clay sized particles) is one of the most important of soil characteristics affecting the function of soils. To better understand the behaviour of soils, reliable spatial estimates of soil texture need to be available. Digital soil mapping has been an enabler in delivering this sort of information. Delivered as two connected pieces, we present new efforts to update the soil texture maps for Australia (Version 1 was delivered in 2015). The main distinguishing enhancement is the merging of field descriptions of soil texture with the traditional laboratory analysed data. This greatly increases the number of available data, yet also calls for an elaboration of methods of how to convert texture class data into continuous variables, how to deal with the associated uncertainties of these conversions, and how these can be propagated in any sort of spatial modelling. Here we report on research to re-calibrate the soil texture centroids that were first determined by Minasny et al. (2007). Then we describe our approach on how the centroids and their uncertainty can be used to generate acceptable soil texture fractions for all qualitive soil profile texture descriptions in the Australian soil database.
Interacting regional policies in containing a disease
Authors: Chandrasekhar Arun G. , Goldsmith-Pinkham Paul , Jackson Matthew O. , Thau Samuel
Published: April 2021

Significance

The lack of coordination between governments on systemic problems, from climate change to financial contagions, has large costs that are well exemplified by a pandemic. We identify which quarantine policies are effective in curbing an outbreak and use that to understand how governments’ prioritization of their own populace and failure to coordinate with neighbors cause quarantines to fail, leading to repeated waves of a disease. Instead, if governments share information and anticipate infections from other jurisdictions, then infections are reduced by an order of magnitude. However, just a few lax governments create jurisdictions that repeatedly incubate a disease and substantially worsen the outcome for everyone. Our techniques should be useful in studying networked interactions across other domains.
Network medicine framework for identifying drug-repurposing opportunities for COVID-19
Authors: Morselli Gysi Deisy , do Valle Ítalo , Zitnik Marinka , Ameli Asher , Gan Xiao , Varol Onur , Ghiassian Susan Dina , Patten J. J. , Davey Robert A. , Loscalzo Joseph , Barabási Albert-László
Published: April 2021

Significance

The COVID-19 pandemic has highlighted the importance of prioritizing approved drugs to treat severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. Here, we deployed algorithms relying on artificial intelligence, network diffusion, and network proximity to rank 6,340 drugs for their expected efficacy against SARS-CoV-2. We experimentally screened 918 drugs, allowing us to evaluate the performance of the existing drug-repurposing methodologies, and used a consensus algorithm to increase the accuracy of the predictions. Finally, we screened in human cells the top-ranked drugs, identifying six drugs that reduced viral infection, four of which could be repurposed to treat COVID-19. The developed strategy has significance beyond COVID-19, allowing us to identify drug-repurposing candidates for neglected diseases.
Optimizing the spectral sharing in a vertical bifacial agrivoltaics farm
Authors: Ammapet Vijayan Ramachandran , Sivanarul Jeevalakshmi , Varadharajaperumal Muthubalan
Published: April 2021

Agrivoltaics (AV) allows double usage of the land by yielding both food and energy. Such farms are more suitable for high population density locations like India. In this work, we study the impact of the vertical, bifacial AV farm on the rice (Oryza sativa) yield in a hot, tropical climate prevailing in the south-eastern part of India (Chennai, 13.0827° N, 80.2707° E). We compare two different bifacial silicon solar cell technologies: (a) passivated emitter rear contact (PERC+), and (b) silicon heterojunction (SHJ), using vertical configurations. We show that SHJ yields more energy than PERC for the considered location, mainly due to its high-temperature coefficient, high inherent bifaciality, spectral and the temperature advantage of the vertical configuration. To maximize both the rice and energy yield with equal importance, we discuss two strategies: (a) varying the pitch of the panels (2 m and 4 m) (b) optimizing the spectral sharing between the panels and plants by reflecting the photosynthetically active radiation incident over the panels (2 m pitch). We found that increasing the pitch of the panels (4 m pitch) could improve the rice yield but drastically reduces the energy yield (∼45% compared to an optimal photovoltaics (PV) farm). Using simulation, we show that by reflecting the small portion of the spectrum (400–500 nm) incident on the PV panels (an additional advantage of the vertical configuration), both the rice and energy yield could achieve a win–win situation (∼80% of rice yield compared to an open farm and 74% of the energy yield compared to an optimally tilted PV farm) with a higher land equivalent ratio of 1.54. The disadvantage of SHJs in the PV farm becomes advantageous in an AV farm due to its low dependence on the reflected portion of the spectrum compared to PERC+ solar cells. This work will motivate the development of low-cost technologies to make spectral sharing a viable option in the future, considering the limited availability of the land.
Alignment of magnetic particles in anisotropic Nd–Fe–B bonded magnets
Authors: Liu X B , Gandha Kinjal , Nlebedim I C , Paranthaman M Parans
Published: April 2021

High-performance anisotropic bonded magnets need a high volumetric filling fraction of magnetic powder in a polymer binder and good alignment while possessing adequate mechanical properties. The correlation between the degree of alignment (DOA) and the volumetric filling fraction of magnetic powder, the type of binder and the processing parameters have been studied using Nd–Fe–B anisotropic bonded magnets. Thermomagnetic analysis and differential scanning calorimetry results show that the magnetic powder can be well aligned in a bonded magnet under an external magnetic field at a temperature higher than the binders’ melting point by 20–60 K, depending on the type of magnetic powder and binder. The DOA results mainly from the interplay between the Zeeman energy (E
app) and the inter-particle static energy (E
stat) in bonded magnets at the chosen alignment temperature and the magnetic fields. A good alignment can be achieved by an alignment magnetic field which is about twice its coercivity in an anisotropic Nd–Fe–B bonded magnet, which is confirmed by our experimental and modeling results.
Charge storage in metal-chalcogenide bilayer junctions
Authors: Takagaki Y
Published: April 2021

We demonstrate that electrical charges are stored in the bilayer junctions of Al and Bi–Cu–S alloys. The junctions exhibit interfacial resistance switching, which is caused by a spontaneous production of high resistivity compounds at the interface and their electrochemical dissolution under a voltage bias. The charge storage results from the redox reactions that are responsible for the resistance switching. In contrast to conventional secondary batteries, the storing capability increases as the temperature is lowered from room temperature to 77 K, where the charges are released in a time scale nearly on the order of hours. The charging and discharging are thereby indicated not to rely on ionic transport. The battery effect is reversible in polarity. Storage characteristics are modified when Cu in the ternary alloy is replaced with Ag or Ni in a similar manner to the way the properties of the interfacial resistance switching are altered.
Determination of interlayer electron mobility in multilayer MoS2 flake using impedance spectroscopy
Authors: Srivastava Shikha , Mohapatra Yashowanta N
Published: April 2021

Layered molybdenum disulfide (MoS2) is emerging as a promising candidate for novel electronic applications, though the focus has largely been on few-layered thin films and in-layer electrical properties. MoS2 shows various nontrivial departures in its electrical properties in comparison to isotropic crystalline materials, however the understanding of anisotropic properties, particularly of charge carrier mobility in MoS2 flakes, is meagre. We experimentally study inter-layer mobility in mechanically exfoliated MoS2 flakes. The choice of a suitable sandwich device structure enables us to study the inter-layer transport using temperature dependent current–voltage (J–V) and impedance spectroscopy. The separation of peaks in the imaginary part of impedance i.e. Im (Z) spectra due to defects and transport in the space charge limited regime allows measurement of mobility un-encumbered by other effects. We study flakes obtained from both naturally occurring and synthetic crystals. The calculated inter-layer mobility (

μ
⊥

) exhibits

μ
⊥

∼

T
δ

temperature dependence with δ = 1.6 and thereby revealing that impurity scattering is the dominant mechanism. A further confirmation that the mobility is limited by charged impurity scattering comes from the observation that it improves for temperatures lower than a characteristic temperature, which marks deionization of donor impurities. Our results provide a direct estimation of the inter-layer mobility in exfoliated MoS2 flakes and would lead to carrier transport engineering and design strategies for applications based on MoS2 flakes.
Hysteretic structural changes within five-layered modulated 10M martensite of Ni–Mn–Ga(–Fe)
Authors: Veřtát P , Seiner H , Straka L , Klicpera M , Sozinov A , Fabelo O , Heczko O
Published: April 2021

Modulated structure of Ni–Mn–Ga-based alloys is decisive in their magnetic shape memory (MSM) functionality. However, the precise nature of their five-layered modulated 10M martensite is still an open question. We used x-ray and neutron diffraction experiments on single crystals to investigate structural changes within 10M-modulated martensite of the Ni50Mn27Ga22Fe1 MSM alloy. The modulation vector gradually increases upon cooling from commensurate q = (2/5) g
110, where g
110 is the reciprocal lattice vector, to incommensurate with q up to pseudo-commensurate q = (3/7) g
110. Upon heating, reverse changes are observed with a thermal hysteresis of ≈60 K. The same hysteretic behaviour was detected in the electrical resistivity and the effective elastic modulus. Scanning electron microscopy showed that the changes are accompanied by the refinement of the a/b laminate. These observations indicate that the commensurate state is a metastable form of 10M martensite. Upon cooling, this phase evolves through nanotwinning into a more irregular and more stable incommensurate structure.
Synthesis and physical properties of perovskite Sm1−x
Sr
x
NiO3 (x = 0, 0.2) and infinite-layer Sm0.8Sr0.2NiO2 nickelates
Authors: He Chengping , Ming Xue , Li Qing , Zhu Xiyu , Si Jin , Wen Hai-Hu
Published: April 2021

Recently, superconductivity at about 9–15 K was discovered in Nd1−x
Sr
x
NiO2 (Nd-112, x ≈ 0.125–0.25) infinite-layer thin films, which has stimulated enormous interests in related rare-earth nickelates. Usually, the first step to synthesize this 112 phase is to fabricate the RNiO3 (R-113, R: rare-earth element) phase, however, it was reported that the 113 phase is very difficult to be synthesized successfully due to the formation of unusual Ni3+ oxidation state. And the difficulty of preparation is enhanced as the ionic radius of rare-earth element decreases. In this work, we report the synthesis and investigation on multiple physical properties of polycrystalline perovskites Sm1−x
Sr
x
NiO3 (x = 0, 0.2) in which the ionic radius of Sm3+ is smaller than that of Pr3+ and Nd3+ in related superconducting thin films. The structural and compositional analyses conducted by x-ray diffraction and energy dispersive x-ray spectrum reveal that the samples mainly contain the perovskite phase of Sm1−x
Sr
x
NiO3 with small amount of NiO impurities. Magnetization and resistivity measurements indicate that the parent phase SmNiO3 undergoes a paramagnetic–antiferromagnetic transition at about 224 K on a global insulating background. In contrast, the Sr-doped sample Sm0.8Sr0.2NiO3 shows a metallic behavior from 300 K down to about 12 K, while below 12 K the resistivity exhibits a slight logarithmic increase. Meanwhile, from the magnetization curves, we can see that a possible spin-glass state occurs below 12 K in Sm0.8Sr0.2NiO3. Using a soft chemical reduction method, we also obtain the infinite-layer phase Sm0.8Sr0.2NiO2 with square NiO2 planes. The compound shows an insulating behavior which can be described by the three-dimensional variable-range-hopping model. And superconductivity is still absent in the polycrystalline Sm0.8Sr0.2NiO2.
Monitoring the process of formation of ZnO from ZnO2 using in situ combined XRD/XAS technique
Authors: Daley Thomas , Opuni Kwasi B , Raj Edwin , Dent Andrew J , Cibin Giannantonio , Hyde Timothy I , Sankar Gopinathan
Published: April 2021

Use of in situ combined x-ray diffraction and x-ray absorption spectroscopy for the study of the thermal decomposition of zinc peroxide to zinc oxide is reported here. Comparison of data extracted from both x-ray diffraction (XRD) and x-ray absorption spectroscopy (XAS) with thermo gravimetric analysis (TGA) enabled us to follow the nature of the conversion of ZnO2 to ZnO. A temperature range between 230 °C and 350 °C appears to show that a very poorly crystalline ZnO is formed prior to the formation of an ordered ZnO material. Both the decrease in white line intensity in the Zn K-edge XANES and resulting lower coordination numbers estimated from analysis of the Zn K-edge data of ZnO heated at 500 °C, in comparison to bulk ZnO, suggest that the ZnO produced by this method has significant defects in the system.
Progress in neutron techniques: towards improved polymer electrolyte membranes for energy devices
Authors: Foglia Fabrizia , Lyonnard Sandrine , Sakai Victoria García , Berrod Quentin , Zanotti Jean-Marc , Gebel Gérard , Clancy Adam J , McMillan Paul F
Published: April 2021

Design and implementation of advanced membrane formulations for selective transport of ions and molecular species are critical for creating the next generations of fuel cells and separation devices. It is necessary to understand the detailed transport mechanisms over time- and length-scales relevant to the device operation, both in laboratory models and in working systems under realistic operational conditions. Neutron scattering techniques including quasi-elastic neutron scattering, reflectivity and imaging are implemented at beamline stations at reactor and spallation source facilities worldwide. With the advent of new and improved instrument design, detector methodology, source characteristics and data analysis protocols, these neutron scattering techniques are emerging as a primary tool for research to design, evaluate and implement advanced membrane technologies for fuel cell and separation devices. Here we describe these techniques and their development and implementation at the ILL reactor source (Institut Laue-Langevin, Grenoble, France) and ISIS Neutron and Muon Spallation source (Harwell Science and Technology Campus, UK) as examples. We also mention similar developments under way at other facilities worldwide, and describe approaches such as combining optical with neutron Raman scattering and x-ray absorption with neutron imaging and tomography, and carrying out such experiments in specialised fuel cells designed to mimic as closely possible actual operando conditions. These experiments and research projects will play a key role in enabling and testing new membrane formulations for efficient and sustainable energy production/conversion and separations technologies.
Thermal properties of energetic materials from quasi-harmonic first-principles calculations
Authors: Fan Junyu , Su Yan , Zheng Zhaoyang , Zhao Jijun
Published: April 2021

The structure and properties at a finite temperature are critical to understand the temperature effects on energetic materials (EMs). Combining dispersion-corrected density functional theory with quasi-harmonic approximation, the thermodynamic properties for several representative EMs, including nitromethane, PETN, HMX, and TATB, are calculated. The inclusion of zero-point energy and temperature effect could significantly improve the accuracy of lattice parameters at ambient condition; the deviations of calculated cell volumes and experimental values at room temperature are within 0.62%. The calculated lattice parameters and thermal expansion coefficients with increasing temperature show strong anisotropy. In particular, the expansion rate (2.61%) of inter-layer direction of TATB is higher than intra-layer direction and other EMs. Furthermore, the calculated heat capacities could reproduce the experimental trends and enrich the thermodynamic data set at finite temperatures. The predicted isothermal and adiabatic bulk moduli could reflect the softening behavior of EMs. These results would fundamentally provide a deep understanding and serve as a reference for the experimental measurement of the thermodynamic parameters of EMs.
Atomic-level characterization of free volume in the structure of Cu67Zr33 amorphous alloy
Authors: Itoh K , Yamada R , Saida J , Ikeda K , Otomo T
Published: April 2021

The structure of Cu67Zr33 amorphous alloy was investigated in terms of packing density and free volume by using neutron, x-ray diffraction and reverse Monte Carlo (RMC) modelling. The RMC model was analysed by a method of decomposing the three-dimensional atomic configuration into fundamental polyhedral units (termed as ‘holes’ referencing the Bernal’s works) of which faces are all triangles consisting of chemical bonds. Not only tetrahedral and octahedral holes but also other larger holes were identified. Moreover, the atomic packing fractions and free volumes in the respective polyhedral holes were evaluated with reference to those for the corresponding crystal structures. The results show that the distribution of free volumes for the larger holes can be described by the exponential function assuming that there are no energetic interactions between each other. On the other hand, the local structural fluctuations due to densely and loosely packed tetrahedral holes were observed, leading to the negative free volume spaces.
Determination of steep sidewall angle using polarization-sensitive asymmetric scattering
Authors: Dou Xiujie , Pereira Silvania F , Min Changjun , Zhang Yuquan , Meng Peiwen , Urbach H Paul , Yuan Xiaocong
Published: April 2021

The sidewall angle (SWA) of a nanostructure exerts influence on the performance of the nanostructure and plays an important role in processing nano-structural chips. It is still a great challenge to determine steep SWAs from far field measurements especially when the SWAs are close to 90°. Here, we propose a far-field detection system to determine steep SWA of a cliff-shape step structure on a silicon substrate by combining a split detector with a scanning method. The far-field radiation field is asymmetric due to the scattering of the step structure, and further numerical analysis demonstrates the reliability of this far-field measurement method. In the simulations, two key variables, i.e. the polarization state and the focus position of the incident laser beam, are considered to explore their impacts. By scanning over the structure laterally and longitudinally with both TE and TM polarizations, polarization effects on the far-field occur. These effects show higher sensitivity to steep SWA variation for TM polarization as compared to TE. Furthermore, with a comprehensive longitudinal scanning analysis for the TM polarization case, a feasible focus interval can be optimized to retrieve the steep SWA. As the proposed method is fast, highly sensitive and easy to implement, it provides a powerful approach to investigate the scattering behavior of nanostructures.
Metal-organic framework derived ultralow-loading platinum-copper catalyst: a highly active and durable bifunctional electrocatalyst for oxygen-reduction and evolution reactions
Authors: Parkash Anand
Published: April 2021

Electrocatalysts with high active oxygen reduction (ORR) and oxygen evolution reaction (OER) activities are key factors in renewable energy technologies. Unlike common strategies for adjusting the proportion of metal centers in a multi-metal organic framework (MOF), herein, we designed and synthesized bifunctional electrocatalysts using cetyltrimethylammonium bromide (CTAB)-capped ultra-low content platinum (Pt) (≤0.5 wt.% Pt) and copper (Cu) nanoparticles and doped on the surface of zinc-based MOF (Zn-MOF-74) and calcinated at 900 °C. According to the electrochemical activity, the Pt/Cu/NPC-900 exhibits superior catalytic activities towards both the ORR with the onset (E
0) and half-wave (E
1/2) potentials were 1.0 V and 0.89 V versus RHE, respectively, and OER (E
o = 1.48 V versus RHE and overpotential (η) = 0.265 V versus RHE) in an alkaline electrolyte at ambient temperature. Also, Pt/Cu/NPC-900 catalyzes through a 4- electron process and exhibits superior stability. Such insightful findings, as well as a newly developed approach, provides rational design and synthesis of an economical and efficient strategy for bifunctional electrocatalyst development.