bluuebunny/crossref_metadata_2025 huggingface dataset:
Femoral head penetration in Vitamin-E polyethylene liner versus conventional liners in total hip arthroplasty: systematic review and meta-analysis of randomised control trials
Authors: Elbardesy Hany , Yadav Himanshu , Rabea Mohamed , Guerin Shane , Harty James
Published: September 2021

Background: Debate encompasses the use of Vitamin E Polyethylene or conventional Polyethylene liner in primary hip arthroplasty. Does the Inclusion of Vitamin E in PE give adequate protection from oxidation and maintains lower rates of wear? Patients and methods: We performed this study following the Preferred Reporting Items for Systematic Reviews and Meta-analyses Statement (PRISMA) and the Cochrane Handbook for systematic reviews and meta-analysis. Studies were included from any region, written in any language. We had only the randomised control trials comparing the femoral head penetration between Vitamin-E diffused highly cross-linked polyethylene (VEPE) liner and conventional liners in primary total hip arthroplasty. Results: We included 10 studies in this meta-analysis. We conducted them using Review Manager V.5.0. We computed the risk ratio to measure the treatment effect, considering the heterogeneity. We used Random-effect models. VEPE had insignificant marginal advantages for FHP within three months post-operative. Additionally, VEPE showed significantly less FHP after two and five years. After one year, it showed significantly less FHP with the VEPE group versus the UHMWPE cohort and a non-significant difference between the VEPE and XLPE group. Conclusions: In terms of FHP, this metanalysis shows less FHP for the VEPE than conventional PE. A longer follow-up period is required to evaluate whether the oxidation protection gained by Vitamin E results in lower wear rates, less osteolysis, and aseptic loosening compared to the conventional PE in the long term.
Theaflavin-3’-O-gallate a Black-tea Constituent Blocked SARS
CoV-2 RNA dependant RNA Polymerase Active-site with Better Docking Results than
Remdesivir
Authors: Banerjee Amrita , Kanwar Mehak , Maiti Smarajit
Published: September 2021

Background Replication of SARS-CoV-2 depends on viral RNA-dependent
RNA-polymerase (RdRp). Remdesivir, the broad-spectrum RdRp inhibitor acts as
nucleoside-analogues (NAs). Remdesivir has initially been repurposed as a
promising drug against SARS-CoV-2 infection with some health hazards like liver
damage, allergic reaction, low blood-pressure, and breathing-shortness,
throat-swelling. In comparison, theaflavin-3’-O-gallate (TFMG),
the abundant black tea component has gained importance in controlling viral
infection. TFMG is a non-toxic, non-invasive, antioxidant, anticancer and
antiviral molecule.

Results Here, we analyzed the inhibitory effect of
theaflavin-3’-O-gallate on SARS CoV-2 RdRp in comparison with
remdesivir by molecular-docking study. TFMG has been shown more potent in terms
of lower Atomic-Contact-Energy (ACE) and higher occupancy of surface area;
−393.97 Kcal/mol and 771.90 respectively, favoured with lower
desolvation-energy; −9.2 Kcal/mol. TFMG forms
more rigid electrostatic and H-bond than remdesivir. TFMG showed strong affinity
to RNA primer and template and RNA passage-site of RdRp.

Conclusions TFMG can block the catalytic residue, NTP entry site, cation
binding site, nsp7-nsp12 junction with binding energy of −6. 72
Kcal/mol with Ki value of 11.79, and interface domain with binding
energy of −7.72 and −6.16 Kcal/mol with Ki value of 2.21
and 30.71 µM. And most importantly, TFMG shows
antioxidant/anti-inflammatory/antiviral effect on human
studies.
Sexual Disorders in Women with Overactive Bladder and Urinary Stress Incontinence Compared to Controls: A Prospective Study
Authors: Naumann Gert , Hitschold Thomas , Frohnmeyer Dominique , Majinge Peter , Lange Rainer
Published: September 2021

Introduction and Hypothesis Female urinary incontinence (UI) has a negative impact on sexual function and sexual quality of life (QoL) in women. But there is still no consensus on the type of UI or the prevalence of sexual dysfunction (SD). The aim of the study was to evaluate sexual disorders in women with overactive bladder (OAB) compared to patients with urinary stress incontinence (SUI) and healthy controls.

Materials and Methods 106 women presenting to a urogynecological outpatient clinic (referral clinic) were investigated using standardized questionnaires and the Female Sexual Function Index (FSFI-d). All 65 incontinent women underwent a full urodynamic examination; the controls (31) were non-incontinent women in the same age range who came for routine check-ups or minor disorders not involving micturition or pelvic floor function. Women with mixed urinary incontinence, a history of previous medical or surgical treatment for UI, recurrent urinary tract infections, previous radiation therapy or pelvic organ prolapse of more than stage 2 on the Pelvic Organ Prolapse Quantification (POP-Q) system were excluded.

Results 100 questionnaires could be evaluated (94.3%). Thirty-four women had urinary stress incontinence, 35 had OAB, 31 were controls. Mean age was 56 years, with no significant differences between groups. The scores of the questionnaire ranged from 2 to 35.1 points. The median score of OAB patients was significantly lower (17.6) than the median score of the controls (26.5; p = 0,004). The stress-incontinent women had a score of 21.95, which was lower than that of the controls but statistically non-significant (p = 0.051). In all subdomains, the OAB patients had lower scores than the stress-incontinent women and significantly lower values than the control group. Most striking was the impairment of “sexual interest in the last 4 weeks”. The figure for “none or almost no sexual activity” was 80% for the OAB group, 64.7% for the group of stress-incontinent women and 48% for the control group. Incontinence during intercourse was reported by one OAB patient and 4 stress-incontinent women but did not occur in the control group.

Conclusions There is a high prevalence of SD in women with urinary incontinence. Patients with OAB reported a greater negative impact on sexual function and had significantly lower scores for the FSFI questionnaire than patients with stress incontinence or controls.
Normvarianten im kindlichen EEG: Pitfalls in der Praxis
Authors: Borggraefe Ingo , Rémi Jan
Published: September 2021

Normvarianten sind nicht obligat auftretenden EEG-Veränderung. Die Kenntnis von Normvarianten ist wichtig, da sie sonst als pathologische Veränderungen fehlinterpretiert werden können. Daraus können klinisch falsche diagnostische und therapeutische Schlussfolgerungen entstehen. Die vorliegende Übersicht dient einer Zusammenfassung und Erläuterung der im Kindes- und Jugendalter auftretenden Normvarianten.
Free Water Protocol
Authors: Schmidt Karolina , Jungbluth Daniela
Published: September 2021

Patienten mit Schluckstörungen aspirieren häufig Flüssigkeiten, was zu schwerwiegenden bronchopulmonalen Komplikationen führen kann. „Free Water Protocol“ ist ein Vorgehen, das bestimmten Patienten das Wassertrinken trotz Dysphagie erlaubt. Im folgenden Beitrag wird der Ansatz vorgestellt und es wird diskutiert, unter welchen Bedingungen das Protokoll klinisch implementiert werden könnte und welche Aspekte Gegenstand weiterer Forschung bleiben.
Late Recovery of Parathyroid Function After Total Thyroidectomy: A Case-Control Study
Authors: Díez Juan José , Anda Emma , Sastre Julia , Corral Begoña Pérez , Álvarez-Escolá Cristina , Manjón Laura , Paja Miguel , Sambo Marcel , Fernández Piedad Santiago , Carrera Concepción Blanco , Galofré Juan Carlos , Navarro Elena , Zafón Carles , Sanz Eva , Oleaga Amelia , Bandrés Orosia , Donnay Sergio , Megía Ana , Picallo María , Ragnarsson Cecilia Sánchez , Baena-Nieto Gloria , Fernández-García José Carlos , Lecumberri Beatriz , de la Vega Manel Sahún , Romero-Lluch Ana R. , Iglesias Pedro
Published: September 2021

The clinical characteristics of patients with postoperative hypoparathyroidism who recover parathyroid function more than 12 months after surgery have not been studied. We aimed to evaluate whether the intensity of replacement therapy with calcium and calcitriol is related to the late recovery of parathyroid function. We compared the demographic, surgical, pathological, and analytical features of two groups of patients: cases, i. e., late recovery patients (those who recover parathyroid function>1 year after thyroidectomy, n=40), and controls, i. e., patients with permanent hypoparathyroidism (n=260). Replacement therapy with calcium and calcitriol was evaluated at discharge of surgery, 3–6 months, 12 months, and last visit. No significant differences were found in clinical, surgical, pathological, or analytical characteristics between cases and controls. The proportion of cases who required treatment with calcium plus calcitriol at 12 months was significantly lower than that found in controls (p<0.001). Furthermore, daily calcium and calcitriol doses in controls were significantly higher than those in cases at 3–6 months (p=0.014 and p=0.004, respectively) and at 12 months (p<0.001 and p=0.043, respectively). In several models of logistic regression analysis therapy with calcium and calcitriol at 12 months was negatively related to late recovery of parathyroid function. Although delayed recuperation of parathyroid function after total thyroidectomy is uncommon (13%), follow-up beyond 12 months is necessary in patients with postoperative hypoparathyroidism, especially in those whose needs of treatment with Ca and calcitriol are reducing over time.
Enantioselective Transfer Hydrogenation of Oxocarbenium Ions Enables Asymmetric Access to α-Substituted 1,3-Dihydroisobenzofurans
Authors: Liu Xigong , Liu Lei , Zhou Likai , Jia Kuiyong
Published: September 2021

Reported here is an efficient enantioselective transfer hydrogenation of cyclic oxocarbenium ions generated in situ through collapse of the corresponding acetal substrates. The asymmetric approach provides straightforward access to a variety of chiral α-aryl substituted 1,3-dihydroisobenzofurans in high yields with excellent enantioselectivities. α-Alkynyl substituted 1,3-dihydroisobenzofurans were also proved to be suitable substrates. In addition, when the reaction was performed at gram scale, the desired product was obtained in good yields with excellent enantioselectivity.
Transmediatisation of the Covid-19 crisis in Brazil: The emergence of (bio-/geo-)political repertoires of (re-)interpretation
Authors: de Souza Júnior Jaime
Published: September 2021

This paper focuses on the centrality of media practices to discuss in a transdisciplinary way how the Covid-19 crisis has been framed and communicated in Brazil across different media spaces, whereas the country became the second in the world with most deaths due to the spread of the Covid-19 infection. This discussion mobilises Foucauldian genealogical and critical discursive perspectives (Foucault, [1970]1981, p. 73) to create intelligibility about how domains of media power-knowledge, such as professional journalism and social media, generate textual trajectories, discursive-semiotic and epistemic disputes through (re-)framings. Based on oligoptic decisions (Latour, 2005, p. 182; Souza Júnior, 2020, pp. 59–64), the article explores a multimodal corpus of transmedia texts. 11 posts have been selected for discussion, since they pave the way for tracing a set of interconnected and (in-)visible elements about the corona crisis. In turn, this paper seeks to: (i) give visibility and qualitatively discuss some of the perspectives that have circulated across media spaces along with their related repertoires of biopolitical and geopolitical (re-)interpretation and (ii) expose the dynamics of power and resistance that emerge through pandemic frames, and how the latter communicate a social event like the Covid-19 crisis.
The effects of ultrafast laser pulse duration on the optical properties of polymers
Authors: Green Leigh Ann
Published: September 2021

Dramatic morphological and optical changes in polypropylene are measured during ultrafast laser micromachining.
Rate of convergence toward Hartree type equations for mixture condensates with factorized initial data
Authors: Lee Jinyeop
Published: September 2021

We consider a system of p species of bosons, each of which consists of N1, N2, …, Np particles. The bosons are in three dimensions with interactions via an interaction potential V such that V ≤ D(1 − Δ), which includes the Coulomb interaction. We set the initial condition to describe a mixture condensate, i.e., a tensor product of factorized states. We show that the difference between the many-body Schrödinger evolution in the mean-field regime and the corresponding p particle dynamics due to a system of coupled Hartree equations is O(N−1), where N=∑q=1pNq.
Gauge freedom in magnetostatics and the effect on helicity in toroidal volumes
Authors: Pfefferlé David , Noakes Lyle , Perrella David
Published: September 2021

Magnetostatics defines a class of boundary value problems in which the topology of the domain plays a subtle role. For example, representability of a divergence-free field as the curl of a vector potential comes about because of homological considerations. With this in mind, we study gauge freedom in magnetostatics and its effect on the comparison between magnetic configurations through key quantities such as the magnetic helicity. For this, we apply the Hodge decomposition of k-forms on compact orientable Riemaniann manifolds with smooth boundary, as well as de Rham cohomology, to the representation of magnetic fields through potential one-forms in toroidal volumes. An advantage of the homological approach is the recovery of classical results without explicit coordinates and assumptions about the fields on the exterior of the domain. In particular, a detailed construction of minimal gauges and a formal proof of relative helicity formulas are presented.
Normal stability of slow manifolds in nearly periodic Hamiltonian systems
Authors: Burby J. W. , Hirvijoki E.
Published: September 2021

Kruskal [J. Math. Phys. 3, 806 (1962)] showed that each nearly periodic dynamical system admits a formal U(1) symmetry, generated by the so-called roto-rate. We prove that such systems also admit nearly invariant manifolds of each order, near which rapid oscillations are suppressed. We study the nonlinear normal stability of these slow manifolds for nearly periodic Hamiltonian systems on barely symplectic manifolds—manifolds equipped with closed, non-degenerate 2-forms that may be degenerate to leading order. In particular, we establish a sufficient condition for long-term normal stability based on second derivatives of the well-known adiabatic invariant. We use these results to investigate the problem of embedding guiding center dynamics of a magnetized charged particle as a slow manifold in a nearly periodic system. We prove that one previous embedding and two new embeddings enjoy long-term normal stability and thereby strengthen the theoretical justification for these models.
Perspective on the Refractive-Index Gas Metrology Data Landscape
Authors: Rourke Patrick M. C.
Published: September 2021

The redefinition of the kelvin has increased focus on thermometry techniques that use the newly fixed value of the Boltzmann constant to realize thermodynamic temperature. One such technique that has advanced considerably in recent years is refractive-index gas thermometry. Generalized as refractive-index gas metrology (RIGM), this also includes a range of applications outside of temperature realizations, such as pressure standards and measurements of the physical properties of gases. Here, the current data situation in the field is reviewed, encompassing the latest developments and remaining challenges, in order to suggest possible approaches for reducing RIGM uncertainties and improving RIGM applications. New analyses of existing experimental literature data are presented for the second density virial coefficient Bρ of helium, neon, argon, and nitrogen; the third density virial coefficient Cρ of nitrogen; and the third dielectric virial coefficient Cε of helium, neon, and argon. A need is identified for more accurate reference-quality datasets to be measured or calculated in several areas, with robust uncertainty budgets, to support future RIGM advancements. The most urgent of these are the bulk modulus of copper; thermodynamic accuracy of the International Temperature Scale of 1990; molar optical refractivity AR of neon, argon, and nitrogen; diamagnetic susceptibility χ0 of neon and argon; second density virial coefficient Bρ of argon; third dielectric virial coefficient Cε of helium, neon, and argon; and third optical refractivity virial coefficient CR of helium and neon.
Tailoring large magnetoresistance in Dirac semimetal SrIrO3 films
Authors: Ren Z. Y. , Miao Jun , Zhang L. P. , Lv Z. L. , Cao J. P. , Jakob Gerhard , Zhou Jing , Chen J. K. , Meng K. K. , Li H. F. , Jiang Y.
Published: September 2021

Perovskite SrIrO3 is a special Dirac material with fascinating effects due to its strong electron correlation and spin–orbit coupling. In this work, a large magnetoresistance (MR) was observed not only in epitaxial SrIrO3 films but also in a SrIrO3/PbZr0.2Ti0.8O3 epitaxial heterostructure with a magnetic field applied perpendicular to the external electric field. The magnetoresistance of SrIrO3 (10 nm) and SrIrO3/PbZr0.2Ti0.8O3 (10 nm/30 nm) reach values as large as 40% and 110% at 9 T and 5 K, respectively. We believe that the unusual magnetoresistance is from the Dirac/Weyl state. Especially, the SrIrO3/PbZr0.2Ti0.8O3 bilayer shows negative magnetoresistance with strong oscillations close to the angle positions, where the magnetic field is parallel to the electric field at 1.8 K, which arises from the chiral anomaly. Based on first-principle calculations and study, the polarization field of PbZr0.2Ti0.8O3 can modulate the band structure of SrIrO3, which can modify the MR of SrIrO3. The SrIrO3/PbZr0.2Ti0.8O3 heterostructure accommodating both the ferroelectric property and the Dirac/Weyl state may open the avenue to manipulate the Dirac/Weyl properties via the electric polarization field.
Full spectrum 2D IR spectroscopy reveals below-gap absorption and phonon dynamics in the mid-IR bandgap semiconductor InAs
Authors: Stingel Ashley M. , Petersen Poul B.
Published: September 2021

While the mid-infrared spectral region spans more than 3000 cm−1, ultrafast mid-IR spectroscopies are normally limited to the spectral bandwidth that can be generated in optical parametric amplifiers—typically a few hundred cm−1. As such, the spectral coverage in conventional two dimensional infrared (2D IR) spectroscopy captures only about 1% of the full potential 2D mid-IR spectrum. Here, we present 2D IR spectra using a continuum source as both the excitation and probe pulses, thus capturing close to the full 2D IR spectrum. While the continuum pulses span the entire mid-IR range, they are currently too weak to efficiently excite molecular vibrational modes but strong enough to induce electronic responses and excite phonons in semiconductors. We demonstrate the full spectrum 2D IR spectroscopy of the mid-IR bandgap semiconductor indium arsenide with a bandgap at 2855 cm−1. The measured response extends far below the bandgap and is due to field-induced band-shifting, causing probe absorption below the bandgap. While the band-shifting induces an instantaneous response that exists only during pulse overlap, the 2D IR spectra reveal additional off-diagonal features that decay on longer timescales. These longer-lived off-diagonal features result from coherent phonons excited via a Raman-like process at specific excitation frequencies. This study illustrates that the full spectrum 2D IR spectroscopy of electronic states in the mid-IR is possible with current continuum pulse technology and is effective in characterizing semiconductor properties.
Nucleus–electron correlation revising molecular bonding fingerprints from the exact wavefunction factorization
Authors: Chen Ziyong , Yang Jun
Published: September 2021

We present a novel theory and implementation for computing coupled electronic and quantal nuclear subsystems on a single potential energy surface, moving beyond the standard Born–Oppenheimer (BO) separation of nuclei and electrons. We formulate an exact self-consistent nucleus–electron embedding potential from the single product molecular wavefunction and demonstrate that the fundamental behavior of the correlated nucleus–electron can be computed for mean-field electrons that are responsive to a quantal anharmonic vibration of selected nuclei in a discrete variable representation. Geometric gauge choices are discussed and necessary for formulating energy invariant biorthogonal electronic equations. Our method is further applied to characterize vibrationally averaged molecular bonding properties of molecular energetics, bond lengths, and protonic and electron densities. Moreover, post-Hartree–Fock electron correlation can be conveniently computed on the basis of nucleus–electron coupled molecular orbitals, as demonstrated for correlated models of second-order Møllet–Plesset perturbation and full configuration interaction theories. Our approach not only accurately quantifies non-classical nucleus–electron couplings for revising molecular bonding properties but also provides an alternative time-independent approach for deploying non-BO molecular quantum chemistry.
Insight into the role of interfaces on mechanical properties of low-porosity Al/Ni compacts: Comparison of experiment and simulation
Authors: Smith Grant D. , Bardenhagen Scott , Nairn John A. , Zahrah Tony , Hooper Joseph P. , Kline Jacob , Kleiser Geremy
Published: September 2021

Quasi-static uniaxial tension and compression, three-point bending, and Hopkinson bar measurements have been carried out on low-porosity Al/Ni compacts (pressed powders) as well as compacts of the constituent Al and Ni. Concurrently, mesoscale material point method (MPM) simulations of fully resolved Al, Ni, and Al/Ni compact microstructures and engineering scale MPM simulations of homogenized Al/Ni compacts have been conducted. These simulations, in conjunction with the experimental measurements, have allowed us to parameterize mesoscale particle/particle contact models and engineering scale anisotropic damage mechanics models for the materials. The goal of this coordinated experimental and simulation study of Al/Ni and its constituent materials was to better understand their mechanical properties and gain insight into the nature of Al–Ni and Al–Al interfaces in Al/Ni compacts and their impact on mechanical properties of the compacts. We found that brittle tensile failure of Al/Ni compacts was dominated by the strength of the Al–Al interface while ductile compressive behavior of Al/Ni compacts was largely determined by the behavior of the Al phase. The properties of both Al–Al interface and Al phase appear to be altered by the presence of Ni. Finally, it was found that softening resulting from shear damage offset underlying strain hardening of the Al and Ni phases during compressive loading of the Al/Ni compacts.
Development of a lumping methodology for the analysis of the excited states in plasma discharges operated with argon, neon, krypton, and xenon
Authors: Souhair N. , Magarotto M. , Majorana E. , Ponti F. , Pavarin D.
Published: September 2021

In this paper, a methodology is presented to compute the plasma properties (e.g.,, density and temperature) accounting for the dynamics of the excited states. The proposed strategy applies to both zero-dimensional (0D) models and multidimensional fluid and hybrid codes handling low-pressure (<50 mTorr) plasma discharges filled with argon, neon, krypton, and xenon gases. The paper focuses on two main aspects: (i) a lumping methodology is proposed to reduce the number of reactions and species considered in order to keep at bay the computational cost without a major loss of accuracy; (ii) the influence that different datasets of cross sections have on the results has been assessed. First, the lumping methodology has been implemented in a 0D model accounting for singly charged ions, neutrals, along with 1s and 2p excited states (Paschen notation). Metastable and resonant are treated as two separate species within the 1s energy level (1sM and 1sR, respectively). The results have been benchmarked against those obtained treating each energy level of the excited states as an individual species. Differences lower than 1% have been obtained. Second, the results of the 0D model have been compared against measurements of electron density and temperature performed on an inductively coupled plasma. Numerical predictions and experiments present a disagreement up to 20%–30%, which is comparable to the uncertainty band of the measurements. Finally, the lumping strategy has been implemented in a 2D fluid code to assess its computational affordability, and the results have been compared against the experiments as well. A variance up to 30% in electron density and temperature is registered adopting different datasets of cross sections.
Emissions of brilliant attosecond pulse in circular polarization by using inclined lasers
Authors: Zhong C. L. , Zhang Y. , Li X. B. , Wang J. , Zhou C. T. , Zhu S. P. , He X. T. , Qiao B.
Published: September 2021

We propose a practical approach to produce intense circularly polarized (CP) attosecond pulses using inclined linearly polarized (LP) lasers from relativistic plasma mirrors. Due to the dynamics of the plasma surface currents at the radiation point, the phase difference of high-order harmonics in the two orthogonal transverse directions approaches π/2 by proper inclination angle and incident angle of the driving laser. One- and three-dimensional particle-in-cell simulations show that CP attosecond extreme-ultraviolet pulses with an intensity about 3.1×1020 W/cm2 are obtained by using a LP laser with an intensity of 1.3×1021 W/cm2, both the inclination and incident angles of which are 45°. This approach is more feasible than previous approaches using CP/two-color driving lasers, and such a CP attosecond source provides a unique tool for a variety of chirality-sensitive applications.
Tri-molybdenum phosphide (Mo3P) and multi-walled carbon nanotube junctions for volatile organic compounds (VOCs) detection
Authors: Muchharla Baleeswaraiah , Malali Praveen , Daniel Brenna , Kondori Alireza , Asadi Mohammad , Cao Wei , Elsayed-Ali Hani E. , Castro Mickaël , Elahi Mehran , Adedeji Adetayo , Sadasivuni Kishor Kumar , Maurya Muni Raj , Kumar Kapil , Karoui Abdennaceur , Kumar Bijandra
Published: September 2021

Detection and analysis of volatile organic compounds' (VOCs) biomarkers lead to improvement in healthcare diagnosis and other applications such as chemical threat detection and food quality control. Here, we report on tri-molybdenum phosphide (Mo3P) and multiwalled carbon nanotube (MWCNT) junction-based vapor quantum resistive sensors (vQRSs), which exhibit more than one order of magnitude higher sensitivity and superior selectivity for biomarkers in comparison to pristine MWCNT junctions based vQRSs. Transmission electron microscope/scanning tunneling electron microscope with energy dispersive x-ray spectroscopy, x-ray diffraction, and x-ray photoelectron spectroscopy studies reveal the crystallinity and the presence of Mo and P elements in the network. The presence of Mo3P clearly enhanced the performance of vQRS as evidenced in sensitivity and selectivity studies. The vQRSs are stable over extended periods of time and are reproducible, making them a potential candidate for sensing related applications.
Millikelvin scanning tunneling microscope at 20/22 T with a graphite enabled stick–slip approach and an energy resolution below 8 μeV: Application to conductance quantization at 20 T in single atom point contacts of Al and Au and to the charge density wave of 2H–NbSe2
Authors: Fernández-Lomana Marta , Wu Beilun , Martín-Vega Francisco , Sánchez-Barquilla Raquel , Álvarez-Montoya Rafael , Castilla José María , Navarrete José , Marijuan Juan Ramón , Herrera Edwin , Suderow Hermann , Guillamón Isabel
Published: September 2021

We describe a scanning tunneling microscope (STM) that operates at magnetic fields up to 22 T and temperatures down to 80 mK. We discuss the design of the STM head, with an improved coarse approach, the vibration isolation system, and efforts to improve the energy resolution using compact filters for multiple lines. We measure the superconducting gap and Josephson effect in aluminum and show that we can resolve features in the density of states as small as 8 μeV. We measure the quantization of conductance in atomic size contacts and make atomic resolution and density of states images in the layered material 2H–NbSe2. The latter experiments are performed by continuously operating the STM at magnetic fields of 20 T in periods of several days without interruption.
Analysis of ionization in air-breathing plasma thruster
Authors: Taploo Anmol , Lin Li , Keidar Michael
Published: September 2021

The primary focus of this work is to study the ionization inside an air-breathing plasma thruster (ABPT) in low earth orbit applications. For this high-speed technology to work, a high degree of ionization needs to be achieved. This paper focuses on plasma chemistry simulation for air in low earth orbits (80–110 km) to explore the possibility of high ionization of the incoming air. The results of plasma chemistry simulation showed the variation of ionization degree and species densities concerning the mean input energy that contributed to the chemical reactions. This research is essential to understand ionization processes to develop a low earth orbit ABPT design. Our results have indicated the possibility of building ABPT without an external neutralizer. The neutralization is created by extracting negative and positive ions to obtain neutralization, thereby eliminating existing design complexity.
Experimental study of atmospheric pressure single-pulse nanosecond discharge in pin-to-pin configuration
Authors: Wang Xingxing , Patel Adam , Bane Sally , Shashurin Alexey
Published: September 2021

We present an experimental study of nanosecond high-voltage discharges in a pin-to-pin electrode configuration at atmospheric conditions operating in a single-pulse mode (no memory effects). Discharge parameters were measured using microwave Rayleigh scattering, laser Rayleigh scattering, optical emission spectroscopy enhanced with a nanosecond probing pulse, and fast photography. Spark and corona discharge regimes were studied for electrode gap sizes of 2–10 mm and a discharge pulse duration of 90 ns. The spark regime was observed for gaps <6 mm using discharge pulse energies of 0.6–1 mJ per mm of the gap length. Higher electron number densities, total electron number per gap length, discharge currents, and gas temperatures were observed for smaller electrode gaps and larger pulse energies, reaching maximal values of about 7.5 × 1015 cm−3, 3.5 × 1011 electrons/mm, 22 A, and 4000 K (at 10 μs after the discharge), respectively, for a 2 mm gap and 1 mJ/mm discharge pulse energy. An initial breakdown was followed by a secondary breakdown occurring about 30–70 ns later and was associated with ignition of a cathode spot and transition to a cathodic arc. A majority of the discharge pulse energy was deposited into the gas before the secondary breakdown (85%–89%). The electron number density after the ns-discharge pulse decayed with a characteristic time scale of 150 ns governed by dissociative recombination and electron attachment to oxygen mechanisms. For the corona regime, substantially lower pulse energies (∼0.1 mJ/mm), peak conduction current (1–2 A), electron numbers (3–5 × 1010 electrons per mm), and gas temperatures (360 K) were observed.
Carbon arc for nanoparticles production: Anode ablation rate and the value of the anode voltage drop
Authors: Nemchinsky Valerian
Published: September 2021

Ablation of a graphite anode by an arc is used to produce nanoparticles. The flow of the ablated carbon particles hampers access of plasma ions to the anode sheath. While the ablation rate is low, ions are still capable of reaching the sheath, where they counter the electric charge of electrons, anode voltage drop is negative. At ablation rates higher than some critical value, the flow of the ablating particles sweeps the plasma ions from the anode proximity; electron electric charge dominates in the sheath and the anode voltage drop turns positive. In these regimes, ions in the plasma move away from the anode and, therefore, they should be generated inside the sheath. The processes in the plasma in the case of positive anode voltage drop together with the process of ion generation inside the sheath are considered. The dependence of the anode voltage drop on the ablation rate is calculated and compared with available experimental data. A good correspondence is found.
Effect field controlled magnetization in NiFe2O4/SrRuO3/PMN-PT heterostructures for nonvolatile memory applications: XMCD study
Authors: Ahlawat Anju , Khan Azam Ali , Deshmukh Pratik , Shirolkar M. M. , Satapathy S. , Choudhary R. J. , Phase D. M.
Published: September 2021

Electric-field controlled magnetism is a potential way to realize strong magneto-electric (ME) coupling for nonvolatile memory applications. The electric field induced nonvolatile modulated magnetization was obtained in NiFe2O4/SrRuO3/Pb(Mg1/3Nb2/3)0.7Ti0.3O3 (PMN-PT) thin film heterostructures. The collective effect of charge and strain significantly modified the magnetization of the NiFe2O4 layer in NiFe2O4/SrRuO3/PMN-PT heterostructures. The analysis of XMCD data establishes that the cation (Fe3+/Ni2+) redistribution occurs on tetrahedral and octahedral sites in the electric field poled NiFe2O4 films, confirming the coupling between magnetism and ferroelectric properties. The films demonstrate repeatable switching of sign of ME output voltage α (α = dP/dH) in response to the applied positive and negative electric pulse, which can be used to store binary information in the nonvolatile manner. The electric-field-controlled switching of α in thin films offers an energy-efficient approach for low-power-consumption nonvolatile memory devices.
A Z-scheme system constructed from WO3 modified TiO2 doped with Cr and Sb for visible light-driven overall water splitting
Authors: Okada Takumi , Miseki Yugo , Gunji Takahiro , Sayama Kazuhiro
Published: September 2021

An artificial Z-scheme system using powder photocatalysts and a reversible redox mediator for the overall water splitting has been attracting attention for producing renewable H2 using solar energy. For the efficient use of this system, the development of efficient photocatalysts utilizing longer wavelength light is essential. TiO2 doped with Cr and Sb (TiO2:Cr/Sb) is one of the visible-light-active photocatalysts which has a bandgap of ca. 2.2 eV and absorbs light up to near 600 nm. However, TiO2:Cr/Sb powder in the Fe3+/Fe2+ reversible redox mediator showed negligible activity under visible light irradiation (λ > 460 nm). In this work, it was found that the photocatalytic performance for O2 evolution over TiO2:Cr/Sb modified with WO3 (WO3-TiO2:Cr/Sb) using the Fe3+/Fe2+ mediator was more than 15 times higher than that without modification. The apparent quantum efficiency of WO3-TiO2:Cr/Sb was estimated to be ca. 0.8% at 510 nm. The overall water splitting activity of Z-scheme water splitting (H2/O2 = 2), in combination with Ru/SrTiO3:Rh, was 9 times improved by the WO3 modification compared to that without modification. From the results of photoelectrochemical measurements, it was surmised that the loaded WO3 on the surface of TiO2:Cr/Sb may promote both reduction of Fe3+ to Fe2+ and oxidation of H2O to O2.
Secondary breakup of shear thickening suspension drop
Authors: Wang Zi-Yu , Zhao Hui , Li Wei-Feng , Xu Jian-Liang , Liu Hai-Feng
Published: September 2021

To explore the effect of shear thickening behavior on the secondary deformation and breakup of cornstarch–water suspension droplets, an experimental investigation is conducted by using a high-speed camera. The experimental results demonstrate suspension droplets that exhibit discontinuous shear thickening (DST) exhibit a hardened deformation mode when they fall into the airflow field. When the droplets are in a hardened deformation mode, the windward side of the droplet deforms into a sheet, while the leeward side remains hemispherical until the droplet leaves the airflow field. The dimensionless number N is established to describe the relative magnitude of the increment of the viscous force and aerodynamic force during the secondary breakup process. Based on the suggested dimensionless number N and the Weber number We, the secondary deformation and breakup regime map of Newtonian fluids and DST suspensions is also proposed.
Non-adiabatic single-electron pumps in a dopant-free GaAs/AlGaAs 2DEG
Authors: Buonacorsi B. , Sfigakis F. , Shetty A. , Tam M. C. , Kim H. S. , Harrigan S. R. , Hohls F. , Reimer M. E. , Wasilewski Z. R. , Baugh J.
Published: September 2021

We have realized quantized charge pumping using non-adiabatic single-electron pumps in dopant-free GaAs two-dimensional electron gases. The dopant-free III–V platform allows for ambipolar devices, such as p-i-n junctions, that could be combined with such pumps to form electrically driven single photon sources. Our pumps operate at up to 0.95 GHz and achieve remarkable performance considering the relaxed experimental conditions: one-gate pumping in zero magnetic field and temperatures up to 5 K, driven by a simple RF sine waveform. Fitting to a universal decay cascade model yields values for the figure of merit δ that compare favorably to reported modulation-doped GaAs pumps operating under similar conditions. The devices reported here are already suitable for optoelectronics applications, and further improvement could offer a route to a current standard that does not require sub-Kelvin temperatures and high magnetic fields.
Physics-based, neural network force fields for reactive molecular dynamics: Investigation of carbene formation from [EMIM+][OAc−]
Authors: Stoppelman John P. , McDaniel Jesse G.
Published: September 2021

Reactive molecular dynamics simulations enable a detailed understanding of solvent effects on chemical reaction mechanisms and reaction rates. While classical molecular dynamics using reactive force fields allows significantly longer simulation time scales and larger system sizes compared with ab initio molecular dynamics, constructing reactive force fields is a difficult and complex task. In this work, we describe a general approach following the empirical valence bond framework for constructing ab initio reactive force fields for condensed phase simulations by combining physics-based methods with neural networks (PB/NNs). The physics-based terms ensure the correct asymptotic behavior of electrostatic, polarization, and dispersion interactions and are compatible with existing solvent force fields. NNs are utilized for a versatile description of short-range orbital interactions within the transition state region and accurate rendering of vibrational motion of the reacting complex. We demonstrate our methodology for a simple deprotonation reaction of the 1-ethyl-3-methylimidazolium cation with acetate to form 1-ethyl-3-methylimidazol-2-ylidene and acetic acid. Our PB/NN force field exhibits ∼1 kJ mol−1 mean absolute error accuracy within the transition state region for the gas-phase complex. To characterize the solvent modulation of the reaction profile, we compute potentials of mean force for the gas-phase reaction as well as the reaction within a four-ion cluster and benchmark against ab initio molecular dynamics simulations. We find that the surrounding ionic environment significantly destabilizes the formation of the carbene product, and we show that this effect is accurately captured by the reactive force field. By construction, the PB/NN potential may be directly employed for simulations of other solvents/chemical environments without additional parameterization.
Effect of solution pH on the characteristics of pulsed gas–liquid discharges and aqueous reactive species in atmospheric air
Authors: Wang Sen , Zhou Zikai , Zhou Renwu , Fang Zhi , Cullen Patrick. J.
Published: September 2021

Solution pH is a significant parameter that affects the electrical characteristics of gas–liquid discharges and thus potentially produces different plasma chemistries for different plasma-engineered applications. In this study, the discharge characteristics and long-lived aqueous reactive species under different initial pH conditions were investigated. It was found that the discharge contained three phases in one pulse cycle, which occurred at the pulse rising edge, the falling edge, and between the rising and falling edges. The discharge intensity and average power at an initial solution pH of 7.0 are much lower than those obtained at an initial solution pH of 5.0 and 9.0. In contrast, the density ratio of N2 (C3Πu, v = 1)/N2 (C3Πu, v = 0) is much higher under neutral solution conditions, indicating that the relatively high vibrational energy was obtained in the gas–liquid discharge plasma. Concentrations of aqueous species H2O2, NO2–, and NO3– are higher at the initial pH of 9.0, indicating that different plasma intensities and chemical compositions (H+ and OH–) are involved in their generation and consumption processes. This study provides insights into understanding and controlling the characteristics of the gas–liquid discharge under different solution conditions.
Hetero-structure mode space method for efficient device simulations
Authors: Shin Mincheol
Published: September 2021

The Hamiltonian size reduction method or the mode space method applicable to general heterogeneous structures is developed in this work. The effectiveness and accuracy of the method are demonstrated for four example devices, such as GaSb/InAs tunnel field effect transistors (FETs), MoTe2/SnS2 bilayer vertical FETs, InAs nanowire FETs with a defect, and Si nanowire FETs with rough surfaces. The Hamiltonian size is reduced to around 5% of the original full-Hamiltonian size without losing the accuracy of the calculated transmission and local density of states in a practical sense. The method developed in this work can be used with any type of Hamiltonian and can be applied virtually to any hetero-structure, and so it has the potential to become an enabling technology for efficient simulations of hetero-structures.
Unconventional Hall effect in metal/semiconductor hybrid spintronic devices
Authors: Kang Jun-Ho , Park Albert Min Gyu , Lee Soogil , Kim Dohyoung , Jung Seyeop , Kim Sanghoon , Park Byong-Guk , Kim Kab-Jin
Published: September 2021

We investigate the Hall resistance of metallic multilayers Ta/Cr/CoTb/Ta/Si. In addition to the anomalous Hall effect originating from the ferrimagnetic CoTb layer, the unconventional Hall effect (UHE) is observed in our multilayer samples. The UHE depends not only on the current and magnetic fields but also on the device geometry and temperature in a unique way. Our results suggest that the UHE does not originate from the spin–orbit torque driven magnetization tilting but occurs possibly due to thermionic emission and Lorentz force at the metal/Si interface, where the Schottky barrier is formed. We also find that the space-charge effect causes geometric dependence of the Hall resistance. The magnitude of UHE is sizable and linearly proportional to the longitudinal magnetic field, suggesting that the observed UHE is attractive to the magnetic-field sensing industry.
Neural networks for on-the-fly single-shot state classification
Authors: Navarathna Rohit , Jones Tyler , Moghaddam Tina , Kulikov Anatoly , Beriwal Rohit , Jerger Markus , Pakkiam Prasanna , Fedorov Arkady
Published: September 2021

Neural networks have proven to be efficient for a number of practical applications ranging from image recognition to identifying phase transitions in quantum physics models. In this paper, we investigate the application of neural networks to state classification in a single-shot quantum measurement. We use dispersive readout of a superconducting transmon circuit to demonstrate an increase in assignment fidelity for both two and three state classifications. More importantly, our method is ready for on-the-fly data processing without overhead or need for large data transfer to a hard drive. In addition, we demonstrate the capacity of neural networks to be trained against experimental imperfections, such as phase drift of a local oscillator in a heterodyne detection scheme.
Scaling law for shock-cell length and its correlation with shock-associated noise of circular and elliptic supersonic free jets
Authors: Perumal Arun Kumar , Rathakrishnan Ethirajan
Published: September 2021

A supersonic core length Lc and an average shock-cell length Ls¯ are experimentally investigated for the acoustic properties of supersonic jets. Following Kumar and Rathakrishnan [“Scaling law for supersonic core length in circular and elliptic free jets,” Phys. Fluids 33(5), 051707 (2021)], a proper scale for the average shock-cell length Ls¯ of circular and elliptic supersonic free jets is found as Ls*¯AR0.2e−0.15γMj2, where Ls*¯ is the average shock-cell length normalized by nozzle throat diameter Dth, AR is the nozzle aspect ratio, γ is the specific heat ratio, and Mj is the ideally expanded jet Mach number. The scaling law developed for Ls*¯ exhibits a close similarity with the scaling law for supersonic core length Lc*AR0.5e−0.11γMj2, where Lc* is the nozzle throat diameter normalized supersonic core length. The scaling laws Ls*¯AR0.2e−0.15γMj2 and Lc*AR0.5e−0.11γMj2 are valid across a wide range of parameters, such as γ from 1.28 to 1.6, the nozzle design Mach number Md from 1 to 2, AR from 1 to 6, and Mj corresponds to the absence of Mach reflection. Discussion conducted on the scaling laws provides important insight into the choice of AR. Furthermore, the relationship between Lc* and Ls*¯ with the intensity of shock-associated noise is also discussed; hence, new correlation functions are developed for Lc* and Ls*¯ that provide an analogous measure of the shock-associated noise.
Breeding season and litter size of the bandicoot, Isoodon macrourus (Marsupialia: Peramelidae), in captivity.
Authors: Gemmell R.T.
Published: September 2021

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Twinning in the genus Macropus, especially M. eugenii (Marsupialia: Macropodidae).
Authors: van Oorschot R.A.H. , Cooper D.W.
Published: September 2021

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Faecal microflora of capt ive koalas, Phascolarctos cinereus (Marsupialia: Phascolarctidae).
Authors: Osawa R. , Mitsuoka T.
Published: September 2021

The faecal microflora of four Phascolarctos cinereus kept at the Saitama Children's Zoo in Japan was investigated using 10 selective and 4 nonselec tive agar media. Total viable counts (in log form) of faecal bacteria (8.2 g of wet faeces) were significantly lower than the direct microscopic counts (11.2 g of wet faeces). Four groups of obligate anaerobes (bacteroidaceae, peptococcaceae, bifidobacteria , and clostridia) and three groups of facultative anaerobes (enterobacteria, streptococci and lactobacilli) were isolated. Dominant components of the flora were obligate anaerobes, in particular bacteroidaceae and peptococcaceae.
Observations on the sk ulls of fossil and extant echidnas (Monotremata: Tachyglossidae).
Authors: Griffiths M. , Wells R.T. , Barrie D.J.
Published: September 2021

The anatomies of four well-preserved, fossilised tachyglossid skulls from Naracoorte, South Australia are described and compared with that of a fossilised skull from north-western Tasmania, with those of 13 extant Long-beaked Echidnas, Zaglossus bruijnii, from New Guinea, and with those of II Short-beaked Echidnas, Tachyglossus aculeatus. The difference in structure and proportions of the rostrums, palates and craniums of the fossil forms from those of Z. bruijnii and T. aculeatus are so great that it is concluded that the former should be placed in a new genus; the name Megalibgwilia is proposed. From the conformation of the rostrum and palate it is suggested that the principal prey of Megalibgwilia was large insects such as scarab and moth larvae, not oligochaete worms as is the case with Z. bruijnii.