bluuebunny/crossref_metadata_2025 huggingface dataset:
Small-Cell Lung Carcinoma in an 8-Year-Old Boy: A Rare Case Report with Review of Literature
Authors: Ghosh Manashi , Debnath Sourav , Bhat Gul Mohammad , Bairwa Sandeep , Rajan Rejil
Published: December 2024

Lung cancer typically affects older adults, with occurrences in children being extremely rare. In adolescents, metastatic lung disease is more common than primary lung cancers. The pathological spectrum of lung cancer in children varies, with small-cell carcinoma being a rare type, accounting for around 4.5% of cases. An 8-year-old boy, previously healthy, presented with moderate-intensity, short-duration chest pain on the left side. Histomorphology, immunohistochemistry characteristics, and fluorescence in situ hybridization confirmed the diagnosis of extensive-stage small-cell lung carcinoma (SCLC). The patient responded positively to six cycles of chemotherapy with etoposide and carboplatin, resulting in the resolution of symptoms. This case underscores the rare instance of SCLC in the pediatric population, emphasizing the diagnostic challenges due to nonspecific symptoms and the necessity for aggressive treatment. It highlights the importance of adapting adult SCLC treatment protocols for pediatric patients to enhance prognosis, given the limited specific guidelines available.
Iatrogenic Acute Spinal Epidural Hematoma in Children
Authors: Elnoamany Hossam , Elkholy Hany , Agour Mazen , Ezat Ahmed , Hammad Amr , Dorrah Mohammed , Elnoamany Nour
Published: December 2024

Spinal epidural hematoma (SEH) is a relatively rare spine space occupying lesion with approximated incidence of 0.1 per 100,000. SEH can be acute or chronic, spontaneous, posttraumatic, or iatrogenic following lumbar puncture (LP) or spine surgery. In this study, we present the case of a 12-year-old girl with a history of leukemia who was referred to us with acute progressive paraparesis and urinary retention following LP that was performed for intrathecal chemotherapy injection. Magnetic resonance imaging revealed SEH opposite the T10–T12 level. Emergency laminectomy and hematoma evacuation were performed. SEH can be a potentially devastating lesion that can result in progressive neurological deficits and permanent disability if it is not diagnosed early and treated properly. Immediate surgical decompression and hematoma evacuation can preserve the neurological function and insure favorable clinical recovery.
The influence of small concentrations of 3He impurities on the velocity of first sound in He ii at low temperatures
Authors: Rudavskiĭ É. Ya. , Chagovets V. K.
Published: December 2024

Precise relative measurements of the velocity of first sound in solutions containing 0.05, 0.155 0.51% 3He have been made in the temperature range 0.1–0.7° K. It was found that the nature of the temperature dependence of the velocity changes with changing 3He concentration. A maximum velocity (the magnitude of which increases with decreasing 3He concentration) is found in very weak solutions, while the velocity falls monotonically with increasing temperature in more concentrated solutions. The dependences obtained cannot be explained within the framework of existing theoretical concepts.
On the theory of the superconductivity of amorphous metals
Authors: Vujičič G. M. , Plakida N. M.
Published: December 2024

Equations for the electron Green's function of a disordered superconductor are derived in the site representation. The superconducting transition temperature is estimated with allowance made for the interaction of the electrons with both the phonons and the quasilocalized excitations of the two-level type in metallic glasses. It is shown that the latter interaction is fairly strong and can lead to a significant increase in the Tc in metallic glasses of the type of PdZr.
Nonlinear electrical conductivity of metallic microcontacts in an alternating electric field
Authors: Omel'yanchuk A. N. , Tuluzov I. G.
Published: December 2024

The problem of the behavior of a point contact between normal metals in an alternating electric field with arbitrary frequency and amplitude is solved using the technique of quasiclassical energy-integrated Green's functions. The nonlinear components of the current due to the electron-phonon interaction are obtained. At the same time, both the frequency dispersion in the effective collision integral, which is important for ω∼ωD (ωD is the Debye frequency) and the frequency dependent effects of the renormalization of the electronic spectrum are included. The kinetic inductance of the contact [Kulik et al, Fiz. Nizk. Temp. 8, 669 (1982)] is proportional to the electron mass renormalized by the electron-phonon interaction m∗=m(1+Λ(e,V,ω)). For ω < ωD and when the bias voltage on the contact eV varies from 0 to ωD, the effective mass varies from m(1+λ~) to m where m is the band mass of the electron, which permits finding directly the electron-phonon interaction constant λ~ The constant component of the additional contact current arising due to irradiation, I(V), is proportional to the transport electron-phonon interaction function Gtr (eV).
Quantum size effects in a Peierls dielectric
Authors: Krive I. V.
Published: December 2024

We have studied the influence of the finite length of a polymer chain on the order parameter of a Peierls dielectric with a doubled lattice period. Within the mean field approximation it is shown that the long wavelength electron-hole quantum fluctuations in a chain of length L are equivalent to the thermodynamic fluctuations with a temperature T=ℏvF/2L, and that for L∼Lc=(π/2)e−cξ0(C=0.57…),ξ0=ℏvF/Δ0, where Δ0 is the equilibrium order parameter for an infinite chain) the Peierls dielectric undergoes a transition to a metallic phase. We consider the coherent and single-particle fluctuations of the order parameter of a Peierls dielectric of finite size.
Nonlinear magnetization waves in superfluid 3He-A
Authors: Poluéktov Yu. M.
Published: December 2024

Equations of motion that we have obtained for the spin vector d completely specify the magnetic dynamics of superfluid 3He-A in the homogeneous case. We consider nonplanar, nonlinear traveling waves with a persistent profile in a magnetic field against the background of homogeneous equilibrium textures with d ‖ I and d ┴ I. An analogy is drawn between the magnetic dynamics of superconducting 3He-A and the magnetic dynamics of antiferromagnets.
Transverse phonon relaxation in He II below 0.7 °K
Authors: Kosevich Yu. A.
Published: December 2024

It is shown that the T−5 temperature dependence of the phonon mean free path in He II, observed experimentally, is related to characteristic features of the phonon dispersion curve. The physical restrictions on the temperature range over which this dependence applies are indicated and also the conditions for a transition to the T−9 dependence predicted earlier.
Effect of depairing in electrodes on the stationary properties of weak links
Authors: Zubkov A. A. , Kupriyanov M. Yu.
Published: December 2024

The effect of depairing processes in electrodes on the stationary properties of short (L≪ξ∗) weak links is analyzed for arbitrary temperatures using the Usadel equations. It is shown that as the parameter γJ=γSL/ξ∗=(σNξS)/(σSL) increases σN1S,ξ∗,andξS are, respectively, the conductivity and damping length of the bridge materials and of the electrodes), the maximum in the function IS(φ) is displaced toward lower values of φ , while the characteristic voltage Vc drops proportionately to γJ−1. The functions Vc(T,γJ) are determined numerically. It is concluded that the decrease in Vc of a SNS sandwich both due to the proxi!llity effect and due to the suppression of the superconductivity of the electrodes by the current is not important if γS≲0.1.
Critical current of weakly coupled superconducting structures on the surface of a degenerate semiconductor in the "dirty" limit
Authors: Alfeev V. N. , Gritsenko N. I.
Published: December 2024

Based on a macroscopic approach, an expression is obtained for the first time for the critical current in quasi-two-dimensional coplanar structures, formed by depositing superconducting film electrodes on the surface of a degenerate semiconductor in the case when electron exchange between the superconductors is related with scattering of carriers by impurities in the semiconducting region. The results of a calculation of the temperature dependence of the critical current of such structures are presented and compared with experimental data.
Effect of the superconducting transition on the amplitude-dependent dislocation internal friction in metals
Authors: Lomakin V. V. , Pankrat'eva G. L. , Roshchupkin A. M.
Published: December 2024

Within the framework of the Granato–Lücke model, taking account of the influence of electronic viscosity on fluctuation unpinning of dislocations from pinning centers we present an explanation of the change that occurs in the amplitude-dependent internal friction during the superconducting transition.
Elastic moduli of inert gas crystals
Authors: Shamfarova O. Ya.
Published: December 2024

The elastic properties of Ar and Kr crystals are studied within the framework of the wave function nodal surfaces model. The influence of the anharmonicity of the vibrations on the elastic moduli is analyzed. The temperature dependence of the elastic moduli of Kr is calculated. A comparison is made of the results obtained here with experimental data and also with the results of calculations for a static lattice.
Detection of the mutual transformation of first and second sounds at a He II-solid helium interface
Authors: Grigor'ev V. N. , Dyumin N. E. , Svatko S. V.
Published: December 2024

The mutual transformation of first and second sounds at an interface separating superfluid and solid helium has been detected in the temperature range from 1.72 to 1.46 °K.
Nature of the negative thermal expansion of solid methane
Authors: Freĭman Yu. A.
Published: December 2024

A mechanism is proposed for the negative thermal expansion of solid methane, which is different from the Yamamoto-Kataoka mechanism. According to this mechanism, the volume change of the crystal with changing temperature (in the temperature range where the usual phonon mechanism is inoperative) is determined by competition between two factors. The contribution to the free energy due to populating of tunnel states of an ordered sublattice on raising the temperature favors contraction of the lattice. The height of the potential barrier separating equivalent orientational minima then increases, the magnitude of the tunneling splitting decreases and the free energy decreases as a result. However, the loss in elastic energy increases with increased contraction, which stabilizes the crystal volume at each temperature. Quantitative agreement between the calculated and existing experimental results was obtained using the mechanism proposed.
Anomalous behavior of the electrical resistance of a superconductor in the intermediate state in the presence of the paramagnetic effect
Authors: Frolov V. A.
Published: December 2024

It is shown that the paramagnetic effect occurring in the intermediate state of a superconductor causes a decrease in the electrical resistance of the material.
Anomalies of the thermal expansion of solid argon due to oxygen impurities
Authors: Tolkachev A. M. , Manzheliĭ V. G. , Kosobutskaya E. A. , Aleksandrovskiĭ A. N.
Published: December 2024

The coefficient of linear expansion (CLE) of solid argon containing 0.5, 1, 2, and 3% oxygen is measured in the temperature range 2–12 °K. Analysis of the concentration dependence of the CLE led to the conclusion that a two-phase region (presumably fcc-hcp) exists in the range of concentration 1.85–3.4% O2. The temperature dependences of the excess CLE (Δα) in the fcc phase correspond to Schottky curves for a two-level system with a two-fold degenerate upper level and splitting equal to 4.0 °K and 4.4 °K for solutions containing 0.5 and 1% O2, respectively. The magnitudes of Δα at low temperatures turned out to be unusually large, an order of magnitude greater than expected from an analysis of the energy spectra of oxygen molecules in a cubic crystal-field and oriented along the ⟨111⟩ direction. The excess CLE of the hcp phase is calculated from the temperature dependence of the CLE in the two-phase region. The difference between its magnitude and temperature dependence and the corresponding data for the fcc phase suggests the existence of different energy spectra of oxygen molecules in these phases.
Superconductivity of cubic tantalum nitride at high pressure up to 12 GPa
Authors: Iľina M. A. , Maĭnashev V. S. , Pashkina T. A.
Published: December 2024

The dependence Tc(P) of specimens of cubic TaN with different deviations of the composition from the stoichiometric composition is investigated. It is found that the Tc(P) curves are discontinuous at pressures P that depend on the starting values of Tc. An x-ray structural analysis of specimens under pressures up to 12 GPa did not reveal the appearance of new crystalline modification of TaN. It is proposed that this form of the dependence Tc (P) in TaN is related with pressure-induced restructuring of the energy spectrum of the carriers.
Experimental investigation of the strong localization of 3He atoms in 4He crystals
Authors: Mikheev V. A. , Maidanov V. A. , Mikhin N. P.
Published: December 2024

Nuclear magnetic resonance measurements have been made of the diffusion coefficient D of the impurity in solid 4He containing 2–4% 3He.

It has been shown that in the region of the low-temperature plateau as the 3He concentration increases, the diffusion coefficient D decreases sharply, which is indicative of the strong localization of 3He atoms in hcp phase of solid 4He. Under these conditions D has been observed to grow gradually as the temperature rises, which is in accordance with Kagan's theory of phonon-stimulated coherent quantum diffusion.
Quantum theory of nonideal crystals
Authors: Vardanyan G. A.
Published: December 2024

A theory which takes account of the characteristic features of quantum crystals is proposed. According to the fundamental paper of Andreev and Lifshitz, these features include the fact that two quasiparticles cannot be located at the same lattice site, that the energy is periodic as a function of the quasimomentum, that the quasiparticle energy band is narrow, etc. The problem of pair scattering of quasiparticles is solved by the method proposed by Lifshitz and Kosevich for describing the process of scattering from stationary defects in crystals. The characteristic features of two-particle scattering in discrete space make it possible to describe the physical picture of quasiparticle motion and to calculate their contribution to the energy of the crystal.

Solutions of 3He–4He quantum crystals are considered in the paper. The existence of the nuclear spins of the 3He atoms make it possible to predict a unique anomaly of vacancies on the initial branch of the stratification curve. The microscopic equations of motion of quantum crystals permit investigation of diverse systems, including hydrogen–metal solutions. On the basis of these equations we consider the process of propagation of oscillations in quantum crystals and in their solutions.

The diffusion of quasiparticles has distinctive features. The exact solution of the problem of the scattering of two quasiparticles makes it possible to ascertain the behavior of the diffusion coefficient for systems in which a constant lattice parameter is ensured by the presence of vacancies in the lattice.
Effects of electron–electron interaction in disordered metal systems
Authors: Al’tshuler B. L. , Aronov A. G.
Published: December 2024

We consider the influence of static defects in metal systems on the damping of single-electron excitations and the one-particle density of states.

It is shown that in disordered metal systems energy relaxation occurs much more rapidly than in an ideal Fermi fluid. The characteristic time is proportional to 1τ2∼(εℏD)d/21ν, where ε is the excitation energy measured from the Fermi level, D is the diffusion coefficient, and υ is the density of states.

The one-particle density of states has a minimum at the Fermi level, as has been often observed experimentally. When a magnetic field H is applied, two maxima for ε = ±gµH/2 are observed in addition to the minimum.
The localization criterion in the field theory of an electron in a random field
Authors: Sadovskii M. V.
Published: December 2024

A general localization criterion for electrons in a random field is considered. The criteria presented in papers by Berezinskii, Gor'kov and Economou and Cohn are demonstrated to be equivalent.

It is proposed that the localization contribution to the two-particle Green's function be sought in the form of a polar term (at zero frequency) with a factorable residue, which determines the localization probability. The residue can be found by solving the homogeneous Bethe-Salpeter equation, which provides a method of determining the position of the mobility threshold (threshold of instability of the metal phase).

It is shown that the position of the mobility threshold coincides with the characteristic energy that specifies the region of applicability of perturbation theory (“the Ginzburg region” in the localization effect).

Within the framework of the instanton approach, the two-particle Green's function is demonstrated to have a singular contribution, corresponding to localization, in the range of energies that correspond to the density-of-states “tail.” In this case the residue at the pole factorizes and its value is determined by the instanton solutions of the effective field theory, comparable with the problem of an electron in a random field.

Within the framework of the formalism of effective action we present a program of a unified consideration of the Bethe-Salpeter and instanton instabilities which lead to localization.
Interaction of localized electrons in crystals
Authors: Kocharyan A. N.
Published: December 2024

The Anderson lattice model, which takes account of the hybridization of the s and f states at neighboring lattice sites, is used to consider phase transitions under pressure to a state with an intermediate valence. The character of change in the interaction between f electrons as the binding energy of the f level decreases is examined; it is found that charge ordering can take place in the system of s and f electrons, depending on the value of the Coulomb f–s interaction.
Dielectric permittivity and the “healing length” in liquid helium films
Authors: Pikhitsa P. V. , Salistra G. I.
Published: December 2024

1. The dielectric permittivity of a liquid helium film between metal plates is calculated with allowance for the long-range forces of the plates. These forces cause a measurable term, that is inversely proportional to the square of the plate thickness, to appear in the reciprocal capacitance of the capacitor formed by the plates.

2. We consider how the inhomogeneous part that is determined in the correlation function by the van der Waals forces affects the spectrum of bulk rotons and the density of the superfluid component in a liquid helium film on a solid substrate. The roton spectrum found has been used to calculate the additional surface density of the normal component. Its temperature dependence and value are fairly close to those observed experimentally.
Anisotropy of the critical current and mechanism of the peak effect in a deformed Nb–Mo alloy
Authors: Vinnikov L. Ya. , Ermolova I. V.
Published: December 2024

The critical currents in a single crystal of the alloy Nb–5.5% Mo, deformed at 77°K, with an anisotropic distribution of dislocations are investigated. Curves of the function Jc (H) exhibit a peak near the upper critical field Hc2, whose height and position change with the angle between the magnetic field and the orientation of the dislocation interlacings extended along ⟨111⟩. The experimental results obtained are compared with the microscopic theory of the peak effect proposed by Larkin and Ovchinnikov. Good qualitative agreement is obtained between theory and experiment.
Magnetoconductivity of thin layers of semimetals in the ultraquantum region of magnetic fields
Authors: Butenko A. V. , Andrievskiĭ V. V.
Published: December 2024

The conductivity of bismuth films in the ultraquantum region of magnetic fields with longitudinal and transverse orientation is investigated. The results agree with Abrikosov's theory of the behavior of the conductivity of semimetals in the quantum limit. The dependence of the impurity concentration on the film thickness is found.
Temperature dependence of the Knight shift in cadmium–magnesium alloys
Authors: Vorontsov S. A. , Grechnev G. E.
Published: December 2024

The contribution from the states on the narrow neck of the hole surface of the second zone (the monster) to the isotropic part of the Knight shift Kiso in cadmium has been calculated. Due to the proximity of EF to the point where the Fermi surface topology changes, the behavior of Kiso with increasing temperature and with the addition of magnesium impurities is mainly governed by rearrangement of the electron spectrum due to the Debye–Waller factor, the impurity potential, and to variations in the lattice parameter. The calculated dependences of Kiso on temperature and concentration in Cd100-xMgx alloys are consistent with the experimental results.
Self-consistent approach in the theory of coupled phonon–ripplon modes of a two-dimensional electron crystal
Authors: Monarkha Yu. P. , Shikin V. B.
Published: December 2024

The spectrum of coupled phonon–ripplon modes of a two-dimensional electron crystal at a liquid-helium surface is calculated analytically in terms of the self-consistent approach. The calculated results are in good agreement with the available experimental data. The possible application of these results in obtaining experimental data on the shear modulus of an electron crystal is analyzed.
Bose spectrum of superfluid He3 films in an electric field
Authors: Brusov P. N.
Published: December 2024

The method of continual integration within the framework of a two-dimensional model is used to investigate the effect of an electric field on the Bose spectrum of superfluid a and b phases of He3 films. It is shown that the electric field in the first approximation only affects the acoustic modes, leading to their anisotropy and decreasing the velocities of sound in directions different from the direction of the field.
Band properties of inert-gas crystals at high pressures
Authors: Ratner A. M.
Published: December 2024

The dependence of band properties on the compression of a crystal is studied with allowance for the polarization contribution to the energy; this contribution, which has hitherto been neglected, considerably facilitates the transition to the metallic state. We show that ionization of the surface layer in contact with another substance is possible (at a lower degree of compression).
Nonlinear current-voltage characteristic of a S–c–N type microcontact
Authors: Khlus V. A.
Published: December 2024

The nonlinear correction to the current–voltage characteristic of a microcontact of the S–c–N type, related with inelastic electron–phonon scattering in the region of the contact, is calculated. As in the normal case, the second derivative of the IVC is related with the electron-phonon interaction function, but the temperature smearing factor as T → 0 changes considerably and, in addition, its characteristic width is determined by the magnitude of the energy gap in the superconducting electrode.
Surface acoustic waves and the temperature dependence of the relaxation time in gallium
Authors: Pisarev L. T. , Popovich A. I.
Published: December 2024

The attenuation of surface acoustic waves in gallium in high magnetic fields has been studied. A method for studying the temperature dependence of the carrier mean free path is proposed. It was established that the temperature dependent part of the collision frequency in gallium is proportional to T2 up to T = 8.5 °K. A logarithmic dependence of surface wave attenuation on mean free path was found in a magnetic field perpendicular to the plane in which the sound propagates.
Resonant tunneling of electrons
Authors: Gogadze G. A. , Dmitrenko I. M.
Published: December 2024

We propose to use the mechanism of Andreev reflection of quasi-particles to form coherent states inside the resonance well of an N–I–S–I–N tunnel structure (I is an insulator, N is a normal metal, and S is a superconductor). The possibility of resonant tunneling of electrons in such structures is discussed.
New inelastic process of phonon scattering by rotons
Authors: Pogorelov L. A. , Sobolev V. I.
Published: December 2024

A new inelastic process has been discovered that determines the kinetics of superfluid helium at elevated pressures. The process involves absorption (emission) of phonons by rotons owing to the dispersion of the roton energy. Rotons moving at maximum velocity are shown to play an essential role in this process. The form of the roton dispersion relation proposed permits a good description of the kinetic processes and the results of direct measurements of the energy spectrum.
Microwave absorption anomalies due to the low dimensionality of the magnetic structure of BaMnF4
Authors: Anders A. G. , Volotskii S. V. , Zvyagin A. I.
Published: December 2024

We investigate absorption bands due to two-magnon processes under parallel microwave pumping. The frequency-field diagram of these bands is determined for different crystal orientations relative to the external field. The value of the weak exchange interaction in the system (J'/J≈10−4) is found from an analysis of the shape of the total absorption band. We find that in an external magnetic field the homogeneous resonance line undergoes an anomalous change in width and a change in its position as the result of the decay of the homogeneous (k = 0) magnon of the high-frequency branch of the spectrum into two magnons of the low-frequency branch. The results are shown to be in good agreement with the predictions of the theory.
Dislocation contribution to the magnetic susceptibility of a metal in the vicinity of a 2 ½-order electronic transition
Authors: Natsik V. D. , Potemina L. G.
Published: December 2024

The contribution of small electronic groups, localized on dislocations, to the paramagnetic susceptibility of metals is analyzed. It is shown that under conditions close to a 2 ½-order topological transition and at sufficiently low temperatures, the dislocation correction to the susceptibility can undergo quantum oscillations as a function of the parameters controlling the chemical potential of the electrons.
Generation of excitations in a superconductor by a sound pulse
Authors: Shumeiko V. S.
Published: December 2024

Multiphonon generation of excitations in a pure superconductor by a longitudinal sound pulse is investigated. The distribution of generated excitations, and the pulse attenuation caused by them, are calculated.
Deep-subwavelength manipulation of waterborne acoustic waves using homogeneous membrane-type reflective metasurfaces
Authors: Hsu Jin-Chen , Alwi Herwandi , Lin Tsung-Yen , Lai Jia-Feng
Published: December 2024

In this study, a homogeneous membrane-type reflective metasurface is proposed to achieve the efficient manipulation of waterborne sounds. The metasurface is single-phase and constitutes only a stiff metal material (stainless steel); furthermore, its thickness can reach the deep-subwavelength range. Each metasurface unit is designed to comprise a cavity capped with a vibrating mass-loaded membrane. We adopt the finite-element method for the dynamic analysis of the fluid–structure interaction problem to simulate the vibroacoustic coupling fields induced by the waterborne acoustic metasurface. We demonstrate that the metasurface units can exhibit high reflectivity for waterborne sound and that vibroacoustic coupling effects are sensitive to variations in the width of the load mass. This enables phase shifts covering the entire 2π range. We reveal the working mechanisms of the membrane structure by examining the vibration modes. The examination reveals that mass–spring resonance and continuum bending vibrations cause steep phase variations in the short- and long-mass regimes, respectively. By adapting the phase profiles, we demonstrate functional manipulation by achieving anomalous reflections, retroreflections, acoustic focusing, and self-bending beams. Our results can potentially facilitate the practical application of metasurfaces in sustainable, lightweight, and high-performance waterborne acoustic devices.
Low temperature heat transport in crystalline bismuth telluride
Authors: Masut Remo A.
Published: December 2024

Thermoelectric (TE) alloys based on Bi2Te3 are under intense development for current large-scale industrial applications. A quantitative understanding of their lattice thermal conductivity κlat is trailing mainly for two reasons: (i) lack of reliable κlat data and, surprisingly, (ii) lack of precise knowledge of the thermal properties of the parent compound, even in its crystalline form. In this work, we examine the existing data on crystalline Bi2Te3 and point out why data below its Debye temperature ΘD are necessary in order to develop a better understanding of heat transfer in the compound and alloys under current development. The measured temperature dependence of κlat from 2–300 K is compared to a simplified heat transport model based on the relaxation time approximation, as well as to more recent and elaborate calculations. Most data on polycrystalline TE materials currently under development only cover a limited temperature range above their Debye temperature ΘD. Yet, comparisons with hot extruded bulk polycrystalline Bi–Sb–Te–Se alloys with compositions close to Bi2Te3 stress the importance of obtaining data below ΘD in order to advance our understanding of the thermal properties of these materials so important for TE applications below 500 K. Attempting to understand and examine the thermal transport of solids based on the approximations involved in the pioneering work of the late 1950s is not justified except below their Debye temperature.
Classification performance improvement in imbalanced circumferential guided wave detection data
Authors: Zhang Yu-hang , Zhang Xu , Gu Yuan-hang , Fu Li-min , Su Xin-ran , Yuan Jun-dong , Wu Qiao
Published: December 2024

Deep learning has significantly advanced the field of pipeline circumferential guided wave testing. However, the scarcity of defective samples in non-destructive testing datasets poses a significant challenge due to data imbalance. Traditional computer vision augmentation techniques, such as rotation and flipping, are often not directly applicable to guided wave data due to its unique characteristics. To address this issue, we propose a novel approach that combines the strengths of convolutional neural networks (CNNs) and random forest (RF) classifiers. Raw detection data are preprocessed using continuous wavelet transform to generate informative time-frequency images. Random forests enhance predictive accuracy by combining multiple decision trees. The experiment results demonstrate the effectiveness of the proposed CNN-RF approach, particularly in handling imbalanced datasets. When the data imbalance ratio is more than 1/2, the shallow, lightweight CNN could effectively extract signal features and lead to approximately a 56.5% speedup. When the imbalance ratio is less than 1/2, the ResNet34-RF model significantly outperforms the standard CNN model. This approach holds potential for contributing to the miniaturization, lightweight design, and mobility of guided wave detection systems and devices.
Assessment of mercury bioaccumulation in a tropical elasmobranch assemblage
Authors: Campos Andréia S. , Bezerra Moisés F. , Moura Victor L. , Faria Vicente V. , Rezende Carlos E. , Bastos Wanderley R. , Oliveira Iuri Aparecida S. , Lacerda Luiz D.
Published: December 2024

Environmental context Mercury (Hg) is a non-essential metal that can accumulate in aquatic biota, including top predators such as elasmobranchs (sharks and rays) and biomagnifying along the trophic web. This study provides data on Hg total, methylmercury (MeHg) and stable isotopes (δ13C and δ15N) for 13 elasmobranch taxa in the Equatorial Western Atlantic Ocean, relating biological and ecological properties with Hg concentrations and the estimated human consumption risk. Rationale Elasmobranchs widely consume fish, making understanding Hg bioaccumulation crucial. Little is known about Hg distribution in their bodies beyond muscle tissue and the associated health risks for both animals and humans who consume them. Methodology This study evaluated Hg, methyl-Hg (MeHg) and stable isotopes (δ13C and δ15N) in the muscle, liver and brain of 13 elasmobranch taxa landed by artisanal fisheries on the Western Equatorial Atlantic Ocean. Results The study revealed that Hg concentrations were highest in muscle tissue, whereas the brain exhibited the greatest percentage of MeHg. Significant correlations between Hg levels and body size, as well as between muscle and brain Hg concentrations, were observed in sharks. Stable isotope values indicated dietary and habitat diversity, and a significant correlation between Hg (log10) and δ15N was found. Mercury concentrations exceeded thresholds for harmful effects in ~76% of the analysed taxa and were also detected in embryos. These taxa also surpassed the local consumption limits, highlighting a potential risk. Discussion The results demonstrated bioaccumulation and biomagnification of Hg in the studied taxa. Muscle Hg was a good predictor of brain Hg levels as a result of the significant correlation between these variables. The high proportion of MeHg in the brain indicates rapid transport of Hg to this organ. Observed Hg concentrations in juveniles and adults may affect their health, whereas concentrations in embryos indicate possible transfer of Hg from the mother to the embryos. This study advises caution when consuming various elasmobranchs, depending on the consumer’s weight and meal frequency.
Capillary-driven self-assembly of soft ellipsoidal microgels at the air–water interface
Authors: Hazra Nabanita , Rudov Andrey A. , Midya Jiarul , Babenyshev Andrey , Bochenek Steffen , Frenken Martin , Richtering Walter , Gompper Gerhard , Auth Thorsten , Potemkin Igor I. , Crassous Jérôme J.
Published: December 2024

The adsorption of ellipsoidal colloidal particles on liquid interfaces induces interfacial deformation, resulting in anisotropic interface-mediated interactions and the formation of superstructures. Soft prolate-shaped microgels at the air-water interface offer an ideal model for studying spontaneous capillary-driven self-assembly due to their tunable aspect ratio, controlled functionality, and softness. These microgels consist of a polystyrene core surrounded by a cross-linked, fluorescently labeled poly(

N

-isopropylmethylacrylamide) shell. By uniaxially stretching the particles embedded in polyvinyl alcohol films, the aspect ratio

ρ

can be finely adjusted.

ρ

was found to vary from 1 to 8.8 as estimated in their swollen conformation at 20
°
C from confocal laser scanning microscopy. The spontaneous interfacial self-assembly at the air–water interface is investigated through fluorescence microscopy, theoretical calculations, and computer simulations. A structural transition occurs from a seemingly random assembly for small aspect ratios to compact clusters, which transform into a side-to-side assembly forming long chains for high aspect ratios. The influence of the poly(

N

-isopropylmethacrylamide) shell on the assembly indicates a significant

ρ

-dependent microgel deformation. This deformation, in turn, determines the average distance between the particles. Consequently, capillary-driven self-assembly of soft anisotropic colloids becomes a powerful mechanism for structuring interfaces and designing microstructured materials.
Little evidence that nonmonogamous family structures are detrimental to children’s well-being in Mpimbwe, Tanzania
Authors: Minocher Riana , Borgerhoff Mulder Monique , Ross Cody T.
Published: December 2024

Nuclear family structures are often thought to be essential for the well-being of children. Divorce, the loss of either biological parent, the presence of step-parents, and the practice of polygynous marriage have all been claimed to negatively impact child well-being. However, empirical research on these topics has been limited by the routine use of cross-regional and cross-sectional databases. Cross-regional data render research vulnerable to the ecological inference fallacy, and cross-sectional data prevent assessment of age-specific impacts of time-varying family-structure variables. When longitudinal data are available, they tend to be drawn from Western/urban contexts. Detailed data on family structure and children’s well-being are rarely collected in more marginalized communities. In many rural and traditional communities, nonnuclear family structures are indeed prevalent and viewed as socially permissible—and, as such, may have different impacts on children’s well-being than in Western contexts. Here, we draw on a detailed, longitudinal dataset from a 20-y prospective study in rural Tanzania, where polygyny and serial monogamy are common. We analyze survival outcomes for 3,693 children born between 1931 and 2014, growth outcomes for 881 children born between 1976 and 2014, and educational outcomes for 1,370 children born between 1976 and 2014. Our analyses indicate that monogamous marriage is not consistently associated with better outcomes for children—contrary to some popular and public health perspectives on human family structure.
A structure-based mechanism for initiation of AP-3 coated vesicle formation
Authors: Begley Matthew , Aragon Mahira , Baker Richard W.
Published: December 2024

Adaptor protein complex-3 (AP-3) mediates cargo sorting from endosomes to lysosomes and lysosome-related organelles. Recently, it was shown that AP-3 adopts a constitutively open conformation compared to the related AP-1 and AP-2 coat complexes, which are inactive until undergoing large conformational changes upon membrane recruitment. How AP-3 is regulated is therefore an open question. To understand the mechanism of AP-3 membrane recruitment and activation, we reconstituted human AP-3 and determined multiple structures in the soluble and membrane-bound states using electron cryo-microscopy. Similar to yeast AP-3, human AP-3 is in a constitutively open conformation. To reconstitute AP-3 activation by adenosine di-phosphate (ADP)-ribosylation factor 1 (Arf1), a small guanosine tri-phosphate (GTP)ase, we used lipid nanodiscs to build Arf1-AP-3 complexes on membranes and determined three structures showing the stepwise conformational changes required for formation of AP-3 coated vesicles. First, membrane recruitment is driven by one of two predicted Arf1 binding sites, which flexibly tethers AP-3 to the membrane. Second, cargo binding causes AP-3 to adopt a fixed position and rigidifies the complex, which stabilizes binding for a second Arf1 molecule. Finally, binding of the second Arf1 molecule provides the template for AP-3 dimerization, providing a glimpse into the first step of coat polymerization. We propose coat polymerization only occurs after cargo engagement, thereby linking cargo sorting with assembly of higher-order coat structures. Additionally, we provide evidence for two amphipathic helices in AP-3, suggesting that AP-3 contributes to membrane deformation during coat assembly. In total, these data provide evidence for the first stages of AP-3-mediated vesicle coat assembly.
Epithelial tubule interconnection driven by HGF-Met signaling in the kidney
Authors: López-García Isabel , Oh Sunhee , Chaney Christopher , Tsunezumi Jun , Drummond Iain , Oxburgh Leif , Carroll Thomas J. , Marciano Denise K.
Published: December 2024

The formation of functional epithelial tubules is critical for the development and maintenance of many organ systems. While the mechanisms of tubule formation by epithelial cells are well studied, the process of tubule anastomosis—where tubules connect to form a continuous network—remains poorly understood. In this study, we utilized single-cell RNA sequencing to analyze embryonic mouse kidney tubules undergoing anastomosis. Our analysis identified hepatocyte growth factor (HGF) as a key potential mediator of this process. To investigate this further, we developed an assay using epithelial spheroids with fluorescently tagged apical surfaces, allowing us to visualize and quantify tubule–tubule connections. Our results demonstrate that HGF promotes tubule anastomosis, and it does so through the MAPK signaling pathway and MMPs, independently of cell proliferation. Remarkably, treatment with HGF and collagenase was sufficient to induce tubule anastomosis in embryonic mouse kidneys. These findings provide a foundational understanding of how to enhance the formation of functional tubular networks. This has significant clinical implications for the use of in vitro–grown kidney tissues in transplant medicine, potentially improving the success and integration of transplanted tissues.
MINFLUX fluorescence nanoscopy in biological tissue
Authors: Moosmayer Thea , Kiszka Kamila A. , Westphal Volker , Pape Jasmin K. , Leutenegger Marcel , Steffens Heinz , Grant Seth G. N. , Sahl Steffen J. , Hell Stefan W.
Published: December 2024

Optical imaging access to nanometer-level protein distributions in intact tissue is a highly sought-after goal, as it would provide visualization in physiologically relevant contexts. Under the unfavorable signal-to-background conditions of increased absorption and scattering of the excitation and fluorescence light in the complex tissue sample, superresolution fluorescence microscopy methods are severely challenged in attaining precise localization of molecules. We reasoned that the typical use of a confocal detection pinhole in MINFLUX nanoscopy, suppressing background and providing optical sectioning, should facilitate the detection and resolution of single fluorophores even amid scattering and optically challenging tissue environments. Here, we investigated the performance of MINFLUX imaging for different synaptic targets and fluorescent labels in tissue sections of the mouse brain. Single fluorophores were localized with a precision of <5 nm at up to 80 µm sample depth. MINFLUX imaging in two color channels allowed to probe PSD95 localization relative to the spine head morphology, while also visualizing presynaptic vesicular glutamate transporter (VGlut) 1 clustering and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) clustering at the postsynapse. Our two-dimensional (2D) and three-dimensional (3D) two-color MINFLUX results in tissue, with <10 nm 3D fluorophore localization, open up broad avenues to investigate protein distributions on the single-synapse level in fixed and living brain slices.
Mutual predictiveness of sound correspondences for reconstruction and language subgrouping
Authors: Lai Yunfan
Published: December 2024

This paper uses Gyalrongic languages, a conservative branch of Sino-Tibetan, to illustrate a new method to
evaluate proto-language reconstructions in general historical linguistics and to conduct exploratory analyses in language
phylogeny. It first reconstructs a proto-system of Gyalrongic preinitials and computes and compares the implicative entropies
between reconstructed and modern systems. In a second step, Mutual Implicative Entropy (MIE) is used to measure genetic distances
between related languages and to generate Neighbornet networks to visualize the subgrouping of Gyalrongic languages. The resulting
networks are in agreement with qualitative historical linguistic analyses and allow adjustments to previous subgroupings obtained
by Bayesian phylogenetic inference. Thus, this method can be used to detect nuances in lower sub-branches, which are sometimes
neglected by lexicon-based methods. Using MIE in historical linguistics is therefore a quick and efficient means of checking the
effectiveness of reconstructions and establishing the accurate preliminary shape of language subgrouping.
A diachronic account of Present Day Standard Danish stop gradation
Authors: Puggaard-Rode Rasmus , Jørgensen Henrik , Horslund Camilla Søballe
Published: December 2024

In certain contexts, Present Day Standard Danish displays an unusual pattern of alternations between voiceless
stops and semivowels often referred to as stop gradation. Stop gradation is traditionally considered a synchronic
phonological process, but evidence for this analysis is based almost exclusively on non-productive morphology. Here, we argue that
the structural generalization captured by a synchronic analysis is better accounted for with reference to the history of Danish,
and to well-understood constraints on articulation and perception which led to prosodically conditioned chain shifts and mergers
through gradual, continuous changes in the realization of consonant allophones. Inspired by the change-chance-choice
model of sound change in Evolutionary Phonology, we outline the historical trajectory that led to the synchronic stop gradation
patterns, and the well-known phonetic pressures underlying them; these pressures pulled the allophone distributions of stops in
different prosodic contexts in very different directions.
Newborn daughters get a fresh start through PI(3,5)P2-mediated vacuolar acidification
Authors: Kane Patricia M.
Published: December 2024

Huda et al. (https://doi.org/10.1083/jcb.202406170) reveal a transient, cell cycle–dependent increase in PI(3,5)P2 levels at the lysosome-like vacuole of yeast daughter cells. The resulting lipid asymmetry alters vacuolar pH in both daughter and mother cells and will impact multiple downstream functions.
Topological rainbow trapping of sound waves in synthesized three-dimensional space for square lattice
Authors: Lu 卢 Jie-Yu 杰煜 , Li 李 Shi-Feng 石峰 , Li 李 Xin 鑫 , Zou 邹 Xin-Ye 欣晔 , Cheng 程 Jian-Chun 建春
Published: December 2024

The three-dimensional (3D) synthetic space offers a platform for exploring the valley Hall insulator, which is usually constructed in graphene lattice. Here, based on the valley transports in the square lattice, we construct a synthetic space by treating the rotation angle as the third dimension and observe the emergent Weyl points in this synthetic space. Since the construction of synthetic Weyl points results in the formation of edge states between the phononic crystal (PC) and the hard boundary, and the factors of rotation angle and the distance from the PC to the hard boundary affect the frequency of these edge states, we can construct topological rainbow concentrator based on the above principles. We conduct a comprehensive numerical and experimental study to explore the characteristics of topological rainbow concentrators. This work may play a driving role in the development of topological rainbow devices.
Elastic properties of Cu–6wt% Ag alloy wires for pulsed magnets investigated by ultrasonic techniques
Authors: Li 李 Ziyu 滋雨 , Gu 顾 Tianyi 天逸 , Wei 魏 Wenqi 文琦 , Yuan 袁 Yang 洋 , Wang 王 Zhuo 卓 , Luo 罗 Kangjian 康健 , Pan 潘 Yupeng 宇鹏 , Xie 谢 Jianfeng 剑峰 , Zhang 张 Shaozhe 绍哲 , Peng 彭 Tao 涛 , Liu 柳 Lin 林 , Chen 谌 Qi 祺 , Han 韩 Xiaotao 小涛 , Luo 罗 Yongkang 永康 , Li 李 Liang 亮
Published: December 2024

Conductor materials with good mechanical performance as well as high electrical and thermal conductivities are particularly important to break through the current bottle-neck limit (∼100 T) of pulsed magnets. Here, we perform systematic studies on the elastic properties of the Cu–6wt% Ag alloy wire, which is a promising candidate material for the new-generation pulsed magnets, by employing two independent ultrasonic techniques, i.e., resonant ultrasound spectroscopy (RUS) and ultrasound pulse-echo experiments. Our RUS measurements manifest that the elastic properties of the Cu–6wt% Ag alloy wires can be improved by an electroplastic drawing procedure as compared with the conventional cold drawing. We also take this opportunity to test the availability of our newly-built ultrasound pulse-echo facility at the Wuhan National High Magnetic Field Center (WHMFC, China), and the results suggest that the elastic performance of the electroplastically-drawn Cu–6wt% Ag alloy wire remains excellent without anomalous softening under extreme conditions, e.g., in ultra-high magnetic field up to 50 T and nitrogen or helium cryogenic liquids.