bluuebunny/crossref_metadata_2025 huggingface dataset:
Cracking the code: the clinical and molecular impact of aminopyridines; a review (2019–2024)
Authors: Khalid Tahira , Malik Ayesha , Rasool Nasir , Kanwal Aqsa , Nawaz Hamna , Almas Iffat
Published: January 2025

Aminopyridines belong to a class of compounds that are monoamino and diamino derivatives of pyridine.
Estimating the Tinnitus Spectrum: A Comparison Between At-Home and Laboratory Measurements
Authors: Lentz Jennifer J. , Liu Yi
Published: January 2025

Purpose:

The purpose of this study was to provide proof of concept for at-home measurements of the tinnitus spectrum.

Method:

Nineteen participants completed pitch similarity ratings in the laboratory and at home. All participants first completed laboratory tests (at 500–16000 Hz) and then later completed at-home tests (at 250–8000 Hz) using their own personal computers and headphones. Six participants repeated these measurements after at least 3 weeks.

Results:

Tinnitus spectra (plots of pitch similarity rating vs. frequency) were analyzed using linear regression and Bland–Altman plots for frequencies that were common to both environments (500–8000 Hz). Although the Bland–Altman plots indicated that absolute ratings used by participants differed in the two settings with online ratings tending to be higher than lab ratings, the regression analysis indicated that the tinnitus spectra had similar shapes (evidenced by significantly positive slopes) between the two environments for 14 of the 19 participants. Similar results were evident for test–retest reliability of the six returning participants in both settings.

Conclusions:

We conclude that the pitch similarity rating method is potentially viable for measuring tinnitus pitch at home. At-home implementation could expedite clinical tinnitus assessments and could be used in conjunction with at-home implementations of tinnitus treatment strategies. However, future studies should include participants who are tested at home prior to being tested in the lab and include an evaluation of extended high frequencies at home.
Successful venous thrombectomy for extensive cerebral venous and sinus thrombosis after failed diagnostic lumbar puncture
Authors: Döring Katja , Ratuszny Dominica , Schuppner Ramona , Giesemann Anja , Bültmann Eva , Lanfermann Heinrich , Abu-Fares Omar
Published: January 2025

With an incidence of 2–5 per million adults, cerebral venous and sinus thrombosis (CVST) is a rarity in the spectrum of cerebrovascular diseases. The etiology and symptomatic presentation are heterogeneous and diverse. CSVT is, therefore, often underdiagnosed. In addition to therapeutic anticoagulation, venous thrombectomy is a last-resort therapy in individual cases.

A 42-year-old woman was admitted to the hospital with postural headache following an unsuccessful lumbar puncture. On suspicion of post-puncture syndrome, analgesic therapy with adjuvant caffeine tablets was initially chosen, leading to rapid improvement and short-term discharge. However, only one day later, the patient presented with a significant worsening of her symptoms and new onset of paresthesia. Since distally accentuated paresis of the left arm also occurred within a very short period of time, a cerebral MRI examination was performed. This revealed an extensive CVST. Due to the extensive CVST and progressive worsening of symptoms, mechanical venous thrombectomy was discussed and performed on an interdisciplinary basis. Mechanical thrombectomy was successful and resulted in complete improvement of symptoms.

The pathophysiological diagnosis is cerebrospinal fluid leak syndrome after unsuccessful lumbar puncture. According to the Monroe-Kellie doctrine, the loss of CSF leads to compensatory dilatation and venous stasis, which in combination can lead to venous insufficiency and promote prothrombotic conditions. Although the available data on the performance of venous thrombectomy suggest caution, there should always be sufficient discretion for individual decision making. As our experience shows, there is a chance of successful venous thrombectomy in the early phase of CVST.
Psychische Erkrankungen im Alter – Warum wir eine neue Sicht
brauchen
Authors: Peters Meinolf , Peters Lisa
Published: January 2025

Klinische Bilder bei älteren Patienten mit psychischen Erkrankungen sind häufig
sehr komplex, einzelne Störungsbilder scheinen weniger abgegrenzt, was sich auch
in epidemiologischen Studien bestätigt. In diesem Artikel wird die These einer
Dedifferenzierung der Krankheitsbilder im Alter entwickelt. Als mögliche Ursache
werden Defizite in den Exekutivfunktionen im Alter diskutiert.
Impact of Frailty on Inpatient Mortality and Resource Utilization for Primary Pulmonary Hypertension
Authors: Rauf Rayaan , Gibson Cheryl A. , Alahmad Mohamad Alhoda Mohamad
Published: January 2025

Background Frailty has been associated with inferior outcomes in patients with primary pulmonary hypertension (PPH). There is a lack of national data to assess if hospital frailty risk score (HFRS) is associated with worse inpatient outcomes in PPH.

Methods Our retrospective study used the Nationwide Readmission Database (NRD). First, we extracted all cases older than 18 years who were discharged with a principal diagnosis of PPH between January and November 2016 to 2019 to allow for a 30-day follow-up. Appropriate survey and domain analyses were applied to obtain national estimates using SAS 9.4.

Results We identified 4,555 cases. HFRS <5 was present in 56% (n = 2,555) of the cohort. Patients with an intermediate-to-high frailty risk score (HFRS ≥5) were older than those with a low frailty risk score (HFRS <5), with a mean age of 61 versus 54 years (p < 0.01), and had slightly fewer women (75 vs. 78%, p = 0.09). Patients with HFRS >5 had a higher prevalence of dementia, depression, diabetes mellitus, malignancy, acute encephalopathy, coagulopathy, heart failure, and chronic (liver and renal) diseases (p < 0.01). Also, they had higher inpatient mortality during index admission (14 vs. 2%, p < 0.001), and all-cause 30-day readmission rates (38 vs. 33%, p = 0.01). Univariate analysis suggests a positive correlation between the degree of frailty and the odds of inpatient mortality (referenced to HFRS <5). The HFRS 5 to 10 group has an odds ratio (OR) of 5 (95% confidence interval [CI]: 3.3–8), the HFRS 10 to 15 group has an OR of 14 (95% CI: 8–23), and the HFRS >15 group has an OR of 20 (95% CI: 9–45). Even after adjusting for age, gender, and significant comorbidities, the single most important factor associated with higher odds of inpatient mortality was HFRS >5 (OR: 5.5 [95% CI: 3.7–8.3], p < 0.001) followed by acute myocardial infarction, acute encephalopathy, heart failure, chronic liver disease, and malnutrition. Length of stay had linear trend with HFRS (mean of 6 days for HFRS <5 vs. 11 days for HFRS 5–10 vs. 19 days for HFRS >10, p < 0.001).

Conclusion Adverse inpatient outcomes correlate with the severity of HFRS in PPH.
Mapping of Endocrinology Training, Certification, and Service Provision in Arab Countries: An Exploratory Survey
Authors: Beshyah Salem A.
Published: January 2025

Background Modern health care and education in Arab countries vary widely. Developing a common understanding of the region's endocrine training, certification, and service models is timely.

Methods We surveyed 63 physicians from 15 Arab countries using an online questionnaire of four domains. They were: (1) informed consent and professional profile; (2) the training, career development, and recognition as an endocrinologist; (3) provision of endocrine services; and (4) the issue of self-proclaimed and recognition of “diabetologists.”

Results Most respondents were senior physicians (82.5%) and adult endocrinologists (53/63). Most respondents (86.7%) confirmed that endocrinology is recognized as a specialty, but only 10.0% stated that it is recognized in major teaching hospitals; 70% of respondents confirmed that a full training program for diabetes and endocrinology exists in their settings; 53.7% stated that postgraduate training in endocrinology requires 2 years with examinations. Half were satisfied, and 25.9% suggested that changes were needed. Regarding endocrine services, 94.8% of respondents reported that the endocrinology is a main service. Diabetes services are reportedly provided mostly by endocrinologists (64.3%). However, nonendocrinologists are involved in diabetes care to a lesser extent. Some specialist services such as lipid clinics, andrology, and reproductive endocrinology are mainly part of endocrinology by 77.2% of respondents and under other specialties by 22.8%. Job opportunities exist primarily in private practice (43.1%) and state hospitals (39.7%). Finally, respondents disagreed with nonendocrinologists' title of “consultant diabetologist” as it is harmful (37.3%) or can be confusing (32.2%) and 22.0% were neutral. Over half (56.7%) stated that academic training courses are welcome to enhance knowledge about diabetes care by primary care doctors but should not be the basis of granting a specialist status.

Conclusions This first look at the mapping of training, certification, and recognition of endocrinologists in Arab countries revealed a wide variation of training systems and care provision. There is a pressing need to address these discrepancies.
Point-contact spectroscopy of platinum
Authors: Krainyukov S. N. , Khotkevich A. V. , Yanson I. K. , Zhalko-Titarenko A. V. , Antonov V. N. , Nemoshkalenko V. N.
Published: January 2025

The point-contact spectra of electron–phonon interaction (EPI) in platinum are measured. The point contact EPI function gpc(ω), one of the transport versions of the thermodynamic EPI function g(ω) that has hitherto been unknown, is reconstructed. The reproducibility of the results is illustrated and the spread of the experimental data is described. Characteristics of a Pt–Cu heterojunction are described. The function gpc(ω) is compared with the most reliable functions of the phonon density of state. The fine structure of the pointcontact spectra is observed and the effect of EPI anisotropy is revealed. The point-contact and thermodynamic EPI functions in platinum are calculated from first principles by taking into account the relative effect within the Dirac equation formalism. With the help of these calculations, the nature of the observed fine structure of gpc(ω) is determined. Absolute values of gpc(ω) and EPI parameter are estimated. The average and mean-square frequencies are determined.
Geometrical nonlinearity in transverse focusing of “hot” electrons
Authors: Kolesnichenko Yu. A. , Shekhter R. I. , Buldovskii V. A.
Published: January 2025

The nonlinearity in transverse focusing of electrons, associated with a change in the size of electron trajectories in a magnetic field H upon an increase in the emitter voltage Ve, is predicted. It is shown that the dependence of the collector signal on the quantities Ve and H is not symmetric with respect to the reversal of the emitter current.
Threshold of combination parametric resonance of spin waves for a second-order Suhl instability
Authors: Borovikov V. S. , Frishman A. M.
Published: January 2025

The parametric instability threshold for the magnon sysem in a transverse microwave field and a longitudinal rf field is studied theoretically under the condition of combined resonance and beyond it. When second-order Suhl instability is taken into consideration, the dependence of the combination parametric resonance threshold on the frequency and amplitude of the rf field displays peculiarities and is not reduced to the results of longitudinal pumping.
Diamagnetic resonance in a metal plate in a normal magnetic field
Authors: Aronov I. E. , Golik A. V. , Korolyuk A. P. , Fal’ko V. L.
Published: January 2025

Experimental and theoretical studies of diamagnetic resonance are carried out under conditions of anomalous penetration of an electromagnetic field in a metal plate with thickness comparable to the electron mean free path. The shape of the resonance lines is studied. It is shown that the electrons in the vicinity of the elliptical reference points on the Fermi surface are responsible for the resonance which causes a variation of the amplitude and position of the Gantmakher–Kaner oscillation peaks.
Elastic properties of superconductors with A 15-type structure
Authors: Balankin A. S.
Published: January 2025

The renormalization of the phonon spectrum induced by the polaron effect in superconductors with A 15-type structure is considered. The electron–phonon interaction constant is used to obtain a microscopic expression for the Poisson ratio σ without any empirical parameters. The results of calculations of σ(λ) and the temperature dependence σ(T) for transition metals and alloys, as well as for six A 15 compounds with known elastic properties, are in good agreement with the experimental data. Elastic properties have been calculated for 30 A 15 compounds for which no experimental data are available.
Polarization of a charge density wave and temperature dependence of the threshold field
Authors: Artemenko S. N. , Volkov A. F. , Kruglov A. N.
Published: January 2025

A qualitative explanation is offered for the shape of the observed temperature dependence of the threshold pinning field of a charge density wave. This explanation is based on a consideration of the screening of the polarized charge density wave by quasiparticles.
Optical transitions in noncollinear antiferrodielectrics. Spin states in the presence of a photoexcited ion
Authors: Petrov É. G.
Published: January 2025

The effect of the variation of the exchange interaction between a magnetic ion and its environment on the magnetization distribution is investigated in the vicinity of the photoexcited ion under the conditions of photoexcitation. In the framework of the molecular field approximation, it is shown that a spin coat is formed near the photoexcited ion when magnetic fields are stronger than the field of the spin-flop phase. The spin states of magnetic ions and the directions of magnetic ion spin ordering in the spin coat are determined.
Electron–phonon interaction in disordered beryllium films
Authors: Butenko A. V. , Bukhshtab E. I. , Kashirin V. Yu. , Komnik Yu. F.
Published: January 2025

Inelastic electron scattering in Be films is investigated experimentally by measuring the localization corrections to the conductivity. The existence of the dependence τϕ ∼ T−2 for T > T0, observed earlier for semimetal films and its absence at T < T0 are confirmed. The temperature T0 corresponds to the equality of the thermal phonon wavelength to the film thickness. A comparison of the obtained experimental results with the theory and with the calculated values of the sound velocity indicates that the inelastic scattering of electrons by transverse phonons plays a decisive role.
N–S boundary resistance determined by “gliding” electrons, and S-shaped current–voltage characteristic
Authors: Kadigrobov A. M.
Published: January 2025

It is shown that in certain physical situations the electrons “gliding” along the N–S boundary are responsible for its significant electrical resistance. In such a case, a transition of a certain part of the sample from the normal to the superconducting state is accompanied by an increase in the total electrical resistance, and the current-voltage characteristic becomes S-shaped. The measurement of the effect makes it possible to determine directly the superconducting gap width, which is important for determining the parameters of high-temperature superconductors.
Thermodynamic properties of CsDy(MoO4)2 at low temperatures
Authors: Anders É. E. , Zvyagin A. I. , Feher A. , Nieki J. , Petrovic P.
Published: January 2025

The peculiarities in the temperature dependence of the heat capacity of the layered crystal CsDy(MoO4)2 are studied experimentally in the temperature range 1.5−20 K. Contributions to the specific heat of the sample in the region preceding the magnetic transition (Tc ≲ 1.5K) are separated. Low-temperature lattice heat capacity data are used to estimate the Debye temperature.
Density and polarizability of liquid 4He
Authors: Kempinski W. , Zuk T. , Stankowski J. , Sitarz S.
Published: January 2025

The temperature dependence of the density of liquid helium is measured in the temperature range from 1.63 to 4.2 K. Instead of the pycnometric technique employed earlier, we use the method of buoyancy. The applicability of the method and of the equipment used for measurements of this kind is discussed. A good agreement is observed with the results obtained by other authors. The results of measurements of the temperature dependence of density ρ and dielectric constant ϵ are used for calculating the dependence of the polarizability A of liquid 4He on temperature and density. These results point towards a complex nature A(T) and A(ρ) dependences, which are found to be mutually correlated.
Method of symmetrical replicas in the cluster model of spin glass
Authors: Vladimir M. I. , Moskalenko V. A. , Skafaru V. V.
Published: January 2025

A cluster model of spin glass is proposed. The effect of clusters on the properties of spin glass is studied by using the method of symmetrical replicas. Basic thermodynamic parameters of the magnetic system are determined and their behavior in the region of critical and low temperatures is studied. A stability criterion of symmetrical-replica solution is obtained for the model under consideration.
Librational excitations in the β-phase of methane
Authors: Lokotosh T. V.
Published: January 2025

The spectrum of collective excitations in the β-phase of methane is analyzed. A distinguishing feature of this spectrum is a significant contribution of swings of molecules in “restricted” sublattices (see James–Keenan model), viz., librons. The symmetry of libron-phonon excitations is studied in detail. A dispersion relation is obtained from three purely libron branches for small values of the wave vector k. The approach proposed in this work correctly describes the molecular motion in the β-phase of methane and considerably simplifies calculations.
Detection of gravitational waves by using coherent effects in superconductors
Authors: Verozub I. V.
Published: January 2025

It is shown that from the point of view of the two-liquid model, nonstationary deformation of a superconductor should noticeably affect the phase of the order parameter. This effect can be used for detecting gravitational waves.
Temperature dependence of the magnetovolume effect in vanadium and palladium
Authors: Panfilov A. S. , Pushkar’ Yu. A. , Svechkarev I. V.
Published: January 2025

The levitation method is used to investigate the dependence of the magnetic susceptibility on pressure up to 2 kbar in vanadium, palladium, and the alloy Pd0.95Rh0.05 at temperatures of 20.4 and 78 K. The obtained results, supplemented by the data obtained from other methods, indicate a strong temperature dependence of the magnetovolume effect in palladium and in the alloy, and an absence of such a dependence in vanadium. A comparison of the low-temperature data in pure metals with the theoretical results reveals considerable discrepancies whose origin is not clear at present.
On the peculiarities of critical fields for inhomogeneous superconducting films
Authors: Glazman L. I. , Dmitrenko I. M. , Kolin’ko A. E. , Pokhila A. S. , Fogel’ N. Ya. , Cherkasova V. G.
Published: January 2025

Experimental studies of thin vanadium films (d = 250−400 Å) have revealed anomalies in the temperature dependence of the upper critical field Hc∥(T) when H is parallel to the sample plane. At a certain temperature T0, a sharp kink is observed between two linear segments in the Hc‖2(T) dependence. The anomaly in the Hc∥(T) dependence of vanadium thin films is explained by assuming that the vanadium film is split into two parallel layers with different parameters (critical temperature Tc, coherence length ξ, thickness d), At temperatures above and below T0, the dependence Hc∥(T) is mainly determined by the characteristics of just one layer. The kink in the dependence Hc‖2(T) is due to a jump-like displacement of the superconducting nucleus from one layer to the other at temperature T0. Anomalies in the dependence Hc∥(T) are also observed in sandwiches consisting of two identical films separated by a thin (∼30 Å) insulating layer. In this case, however, the transition from one segment to the other is smooth. In the case of identical layers, a peculiar crossover is observed: if for T→Tc the critical field Hc∥(T) is equal to its value for a layer of double thickness, then Hc∥(T) asymptotically approaches the critical field for one layer upon a decrease in temperature. The calculations made with the help of this model provide a satisfactory explanation for the experimental results.
Peculiarities of low-temperature thermal resistance of aluminum in a magnetic field
Authors: Gostishchev V. I. , Drozd A. A. , Sobol’ V. R.
Published: January 2025

Low-temperature (T = 5−50 K) heat transfer in transverse magnetic fields up to 50 kOe is investigated in rectangular samples of pure polycrystalline aluminum. The thermal resistances WH and W with and without a magnetic field, respectively, are found to have different temperature dependences. This means that the magnetic field smooths the power dependence of WH on temperature over a wide temperature interval. Consequently, the thermal magnetoresistance ΔWH/W(ΔWH/W = (WH—W)/W) is a nonmonotonic function of temperature, the magnitude and position of the extremum depending on the magnetic field. These peculiarities are related to an increase in the magnetic transfer diffusion over the Fermi surface with increasing temperature, and to a transformation of closed orbits of some carriers into elongated orbits, which leads to a change in the integral functional dependence of transverse diagonal components of thermal conductivity tensor on magnetic field.
Surface melting of atomic cryocrystals
Authors: Krainyukova N. V.
Published: January 2025

The quasi-harmonic instability of a cryocrystal surface is studied by using a simple isotropic model of an fee crystal. The interaction of atoms is described by the Lennard-Jones potential whose parameters are fitted with experimental results. It is shown that the bulk instability occurs at temperatures that do not differ from the melting point of the Ne, Ar, Kr, Xe crystals under investigation. The surface instability sets in at temperatures that are 0.71, 0.76, 0.77, and 0.78 of the bulk instability temperatures of Ne, Ar, Kr, Xe, respectively.
Anisotropic exciton-magnon light absorption in manganese fluoride
Authors: Shapiro V. V. , Faingol’d V. L. , Peresada A. V.
Published: January 2025

A dependence of exciton-magnon absorption coefficient (the optical transition bA1g (6S) → 4T1g (4P)) on the antiferromagnetism vector orientation relative to the C4 crystallographic axis is discovered in antiferromagnetic manganese fluoride. The dependence is interpreted in terms of the phenomenological approach.
Thermal and electric conductivity of metal-oxide ceramics Y–Ba–Cu–O in the superconducting transition region
Authors: Merisov B. A. , Khadzhai G. Ya. , Obolenskii M. A. , Gavrenko O. A.
Published: January 2025

The thermal conductivity and electrical resistivity of the high Tc superconductor Y1.2Ba0.8CuO4−δ are investigated experimentally in the temperature interval 77−300 K (Tc = 91 K). A correlation between temperature dependences of these quantities is detected in the region of superconducting transition.
Antiferroelectric resonance of centrosymmetric multisublattice magnets
Authors: Yablonskii D. A. , Krivoruchko V. N.
Published: January 2025

It is shown that the natural oscillation spectrum of centrosymmetric multisublattice magnets contains resonance of the dipole-active type. The theory of the rf field excitation of such oscillations is developed.
Current states in an SNINS junction near the critical temperature
Authors: Akhramovich L. N. , Svidzinskii A. V.
Published: January 2025

The current in an asymmetric SNINS junction is calculated at nearly critical temperatures by using the microscopic theory. It is shown that the tunnel current depends significantly on the position of the insulator in the N-layer. Among other things, the temperature dependence of current for low transparencies of tunnel junction varies with the position of the insulator.
Magnetoplasma oscillations of a two-dimensional electron layer in a bounded system
Authors: Kosevich A. M. , Kosevich Yu. A. , Granada J. C.
Published: January 2025

The spectrum of magnetoplasma oscillations of a two-dimensional electron layer in a bounded screened system is studied. It is shown that under certain conditions there exist oscillations whose frequencies are considerably lower than the electron cyclotron frequency. The wave-guide-type electromagnetic oscillations are described, whose frequencies experience in a strong magnetic field a shift and a splitting which are inversely proportional to the external magnetic field and to the transverse dimension of the system.
The effect of phase and inelastic relaxation of electrons on superconducting properties of bismuth amorphous films
Authors: Belevtsev B. I. , Komnik Yu. F. , Fomin A. V.
Published: January 2025

The influence of the enhancement of electron elastic scattering, whose measure is the magnitude of resistance “per square” R□, on the superconducting transition temperature Tc of cold-deposited amorphous bismuth films of thickness less than 100 Å is analyzed. It is found that a decrease in Tc with increasing R□ correlates with the enhancement of inelastic and phase relaxation of electrons. The formula proposed on the basis of the analysis describes the experimental dependence Tc(R□) and takes into account the decrease in the phase relaxation time τϕ with increasing T□ Investigations of the dependence of fluctuation conduction above Tc on temperature and transverse magnetic field reveal deviations from the Aslamazov–Larkin and Maki–Thompson corrections for ε > εt (ε = In (T/Tc)). The values of εt vary from 0.5 to 0.25 and increase with R□ These effects are explained by the effect of inelastic electron–phonon collisions leading to a decrease in τϕ with increasing temperature and to a corresponding increase in the pair braking parameter r = In (Tc0/Tc) (Tc0 is the unperturbed value of Tc).
Phase diagram for O2–Kr system
Authors: Baryl’nik A. S. , Prokhvatilov A. I.
Published: January 2025

A complete phase diagram has been obtained for the first time as a result of x-ray studies of O2–Kr solutions. It is characterized by the presence of triple peritectic and eutectic points on the liquidus-solidus curves and three eutectoid transformations at temperatures 50, 42, and 23 K in the region of solid solutions. The boundaries of the limiting mutual solubility of the components in the region of coexistence of equilibrium phases are determined. Two metastable phases having hcp and fcc structure are observed. It is proposed that the metastable fcc phase of oxygen is disordered relative to orientations of O2 molecules.
Zeeman effect studies of low-energy states of KDy(MoO4)2 in the region of low-temperature phase transition in optical range
Authors: Bagulya V. A. , Zvyagin A. I. , Kut’ko V. I. , Mil’ner A. A. , Skorobogatova I. V.
Published: January 2025

Zeeman splitting of electron optical transitions of Dy3+ ions in KDy(MoO4)2 is investigated at temperatures above and below the temperature of structural phase transition (SPT). Experimental results are compared with the data calculated in the crystal field approximation for the microscopic model describing SPT in terms of multiplication of a crystal unit cell and the rhombic distortion of quasitetragonal centers of the Dy3+ ions.
Kinetic coefficients of high-temperature superconductors in simple models of their electron spectrum
Authors: Kopeliovich A. I.
Published: January 2025

An explanation is offered for the observed experimental anomalies in the temperature dependence of the Hall constant, thermo-emf, and electrical resistivity of yttrium-based high-temperature superconductors (HTS) in the normal state. It is shown that in the two-dimensional models of the electron spectrum, the Hall constant and thermo-emf are extremely sensitive to small variations Δn of the carrier concentration. The electric resistivity is much less sensitive to Δn if there is no dielectric gap near the Fermi level.
The influence of spin–orbital interaction on electron structures of Sb and As
Authors: Pospelov Yu. A. , Novikov S. G.
Published: January 2025

The effect of spin–orbital interaction (SOI) on the electron spectra of Sb and As is calculated by using a recently developed approach (V. I. Mel’nikov and Yu. A. Pospelov, Deposited in VINITI on July 19, 1988, No. 5814-B88) based on the pseudopotential method. The calculations show the simplicity and effectiveness of this approach and lead to a number of new physical results which are thoroughly discussed in the article. It is shown, in particular, that the consideration of SOI results in corrections of different signs to the overlapping of valence and conduction bands for Sb and As.
Weakly attenuating waves in metals in multichannel surface scattering of conduction electrons
Authors: Kirichenko O. V. , Peschanskii V. G.
Published: January 2025

It is shown that under the conditions of anomalous skin effect in metals with a smooth surface, weakly attenuating waves appear due to multichannel specular reflection of charge carriers. Such waves are not observed in samples with a rough surface. The amplitudes of these waves and the nature of their attenuation in the bulk of metal are very sensitive to the polarization of an electromagnetic wave incident on the metal. The velocity of propagation of the waves coincides with the maximum and minimum velocities of an electron along the normal to the sample boundary in the region of variation of the number of channels of specular reflection on the Fermi surface.
On the possibility of trigger effect in velocity and absorption of sound in metals
Authors: Deineka E. Yu. , Kabanov A. E. , Fil’ V. D. , Burma N. G.
Published: January 2025

The existence of states with an ambiguous angular dependence of the velocity and absorption of sound is predicted in a narrow interval of deviation angles in classically strong magnetic fields under the conditions of the deviation effect (DE) [D. H. Reneker, Phys. Rev. 115, 303 (1959)].
Low-temperature and magnetoresonance properties of a layered CsGd(MoO4)2 crystal
Authors: Feger A. , Stefanyi P. , Orendacova A. , Anders É. E. , Anders A. G. , Volotskii S. V. , Zvyagin A. I. , Startsev S. V. , Khats’ko E. N. , Chernyi A. S.
Published: January 2025

Low-temperature dependences of heat capacity, magnetic susceptibility and EPR of a layered CsGd(MoO4)2 crystal are investigated. The structure of energy levels 4S7/2 of the ground state of Gd3+ in CsGd(MoO4)2 is determined. The magnetic contribution to heat capacity is isolated by taking into account the single-ion anisotropy in the vicinity of magnetic phase transition at Tc = 0.448 K. The exchange parameters J1 and J2 are estimated.
Heat transfer in conductors of cylindrical cross-section with diffusive boundary scattering
Authors: Amrit J. , Niemchenko K. , Niemchenko Ye. , Rogova S. , Vikhtynska T.
Published: January 2025

We present a theoretical study of heat transfer properties in three-dimensional cylindrical conductors of finite lengths in the ballistic regime of phonon propagation. The phonon emission is considered to be radiative and its interactions with the lateral boundary is assumed to be completely diffusive. The main goal of this study is to determine the temperature profile and the features of its formation for the generalized case of a conductor of finite length. A matrix numerical solution of the integral equation for the particle energy flux is obtained and an approximate analytical solution of this equation is proposed. The heat flux and thermal conductivity coefficient are determined; and the significant difference between our results and those of the generally accepted formulation in the Knudsen regime and the Casimir model is discussed.
Structural defects and heat capacity of iodide cadmium
Authors: Rudka Mykola , Orendáč Martin , Tarasenko Robert , Karkulovska Mariana , Seredyuk Bohdan , Tovstyuk Nataliia
Published: January 2025

In this work, a creation of donor-acceptor (DA) complexes (trimmers) in highly anisotropic layered crystals of CdI2 is analyzed. The impact of DA complexes on lattice dynamics is investigated. Experimental studies of the temperature dependence of the heat capacity of crystals were applied and the significant impact of impurities in the crystal matrix was revealed. Einstein temperatures for samples of CdI2, CdI2 with Cu, CdI2 with Cu, Au were calculated for the first time and the consistency of the proposed model with theory and experiment is demonstrated.
Tunnel magnetic contacts with perpendicular anisotropy of magnetic electrodes as promising elements for recording information
Authors: Krupa M. M.
Published: January 2025

In this work, we present the results of our research of resistance and capacitance changes of tunnel magnetic contacts, in which the magnetic electrodes have perpendicular anisotropy. The paper proposes a mechanism that explains the appearance of tunnel magnetic capacitance in these contacts and presents the results of measurements of the value of tunnel magnetic resistance and tunnel magnetic capacity in tunnel contacts Tb22–δCo5Fe73/Pr6O11/Tb19–δCo5Fe76, where the value of tunnel magnetic resistance is almost 100%, and the value of the tunnel magnetic capacity is more than 80%. It is shown that tunnel magnetic contacts with perpendicular magnetization of electrodes can have a good prospect of practical use in the development of spintronics elements. The work also provides a structural diagram of the construction of an information carrier based on tunnel magnetic contacts and describes the principle of recording information in such a structure.
Binding characteristics of systemic glucocorticoids to the SARS-CoV-2 spike glycoprotein: In silico evaluation
Authors: Khmil N. V. , Kolesnikov V. G. , Boiechko-Nemovcha A. O.
Published: January 2025

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) poses a serious threat to people worldwide causing a variety of diseases, manifesting with intestinal, respiratory, hepatic, and neurological symptoms. The therapeutic strategy to counteract SARS-CoV-2 encompasses antiviral drugs, monoclonal antibodies, as well as immunomodulatory drugs, such as systemic glucocorticoids which may benefit patients with middle and severe COVID-19. The spike glycoprotein (S protein), which recognizes the host cell receptor and initiates the attachment of SARS-CoV-2 to it, can be considered a potential target for glucocorticoids. However, the mechanism of glucocorticoid inhibitory action against the S protein is currently unclear due to insufficient study of the ligand-binding sites on the S protein. The aim of the study was to evaluate the binding characteristics of systemic glucocorticoids to the SARS-CoV-2 S protein and to elucidate the topological features of non-covalent ligand-protein complexes. AutoDock Vina was used for molecular docking studies against the SARS-CoV-2 S protein with ligands. Dexamethasone (DEX), methylprednisolone (Medrol), triamcinolone (TAC), and prednisone (PRED) were selected as ligands. The Open Babel 3.1.1 software was used to prepare ligand structures. Two 3D structures of the S protein which have open (RBD-up) and closed (RBD-down) conformations in the receptor-binding domain (PDB ID: 6VYB, and PDB ID: 6VXX), respectively, were used as docking targets (www.rcsb.org). Ligand interactions with amino acid residues were identified using the PLIP web tool (https://plip-tool.biotec.tu-dresden.de). Visualization of docking results was implemented in PyMol 2.5. Docking study demonstrated that all glucocorticoids can bind to multiple sites in the SARS-CoV-2 S protein, including the receptor-binding fragment (S1) and the fusion fragment (S2). Methylprednisolone showed the best affinity with the S protein in RBD-up conformation than other glucocorticoids, with a binding free energy of –9.7 kcal/mole and an inhibition constant value of 0.08⋅10–6 M. Triamcinolone demonstrated a high affinity with the S protein in RBD-down conformation, at which the binding free energy was −8.8 kcal/mole and an inhibition constant value was 0.36⋅10–6 M. Our results show that Gly744, Asp745 and Arg1000 are mainly involved in the stabilization of complexes through the hydrogen bonds. Hydrophobic interactions are primarily mediated by Thr572, Ile587, and Val976. These results are an important basis for the development of potential drugs against SARS-CoV-2.
More on the size effects on the spectral figure of merit and enhancement of the local fields in the neighborhood of biconical and bipyramidal metallic nanoparticles
Authors: Korotun A. V.
Published: January 2025

Optical properties of biconical and bipyramidal nanoparticles, which are equivalent to prolate and oblate spheroids, are studied. The relations for the frequency dependences for the diagonal components of the tensors of enhancement of local electric fields and spectral figure of merit tensor, as well as for the size dependences of the longitudinal and transverse spectral figure of merit, frequencies of the longitudinal and transverse surface plasmonic resonance, and effective relaxation rate are obtained. The proximity of the frequency dependence curves of the transverse and longitudinal components of the field enhancement tensors and spectral figure of merit tensor for biconic and bipyramidal particles indicates the possibility of studying the optical properties of bipyramids, most often obtained in the synthesis of nanoparticles, using the relations for bicones. The character of evolution of maxima of the longitudinal and transverse components of the field enhancement tensor under the variation of effective aspect ratio is determined. The existence of the limit to which the values of the transverse and longitudinal figure of merit asymptotically tend with increasing frequency is established. The fact of decreasing of the splitting of the surface plasmonic resonance frequency when the shape of the equivalent spheroid approaches the spherical one is proved. The qualitative coincidence of the theoretical and experimental results for the size dependence of the effective electron relaxation rate in biconic nanoparticle whose height is greater than the diameter is demonstrated.
Microwave thermal imaging system for debonding detection of radar absorbing materials
Authors: Tu Yihang , Tang Ziqiao , Qiu Yang , Wang Beibei
Published: January 2025

In this paper, a microwave thermal imaging system (MTIS) has been presented for debonding detection of radar absorbing materials (RAMs). First, an overview of the mechanism underlying microwave heating and the fundamental principle of defect detection within RAMs is presented. Then, a multifunctional MTIS capable of performing both microwave lock-in thermography (MLIT) and long-pulse microwave thermography (LPMT) has been introduced, specifically tailored for the in situ inspection of RAMs. In addition, in this system, the detection area for a single scan is 90 * 90 mm2, with the emission source operating at a frequency of 5.8 GHz and boasting a maximum output power of 20 W. Next, based on MTIS, the above-mentioned two thermography techniques are applied to detect defects in RAMs. In addition, thermal contrast (Tc) and signal-to-noise ratio are introduced for the analysis of imaging results. Finally, the results show that LPMT can be used for preliminary detection of debonding defects in RAMs, while MLIT can be further used for detailed detection of debonding defects in RAMs. In addition, the minimum detection time of this MTIS is 45 s, and the minimum detectable defect aperture is 3 mm.
Ferroelectric polarizations engineered reversible skyrmion–bimeron switch in van der Waals heterostructure RuClBr/Ga2S3
Authors: Lei Yong , Sun Wei , Niu Xianghong , Zhou Wenqi , Yu Xueke , Liu Yongjun , Zhang Xiuyun
Published: January 2025

Controllable operation between different magnetic topological states, such as skyrmions and bimerons, which share the same topological charge but exhibit distinct properties, has garnered extensive attention due to their potential applications in future high-density memory technologies. However, their remarkable origin mechanisms (e.g., in-plane and out-of-plane easy magnetic axis) make effective control of their switching a huge challenge. Based on first-principles calculations, we explore the 2D RuClBr/Ga2S3 van der Waals heterostructure and find that the skyrmion and bimeron topological states could be switched instantaneously and efficiently by regulating the electric polarization of Ga2S3 with an external electric field. Additionally, atomic spin dynamic simulations reveal that the evolved skyrmion and bimeron magnetic configurations are highly resistant to external disturbances, enduring external magnetic fields of up to 20 T. This efficient transformation between magnetic states is driven by magnetic anisotropy accompanying changes in the polarization state. Our work predicts that the RuClBr/Ga2S3 system is an ideal platform for addressing this control problem.
CG modeling of nucleosome arrays reveals the salt-dependent chromatin fiber conformational variability
Authors: Sun Tiedong , Korolev Nikolay , Lyubartsev Alexander P. , Nordenskiöld Lars
Published: January 2025

Eukaryotic DNA is packaged in the cell nucleus into chromatin, composed of arrays of DNA–histone protein octamer complexes, the nucleosomes. Over the past decade, it has become clear that chromatin structure in vivo is not a hierarchy of well-organized folded nucleosome fibers but displays considerable conformational variability and heterogeneity. In vitro and in vivo studies, as well as computational modeling, have revealed that attractive nucleosome–nucleosome interaction with an essential role of nucleosome stacking defines chromatin compaction. The internal structure of compacted nucleosome arrays is regulated by the flexible and dynamic histone N-terminal tails. Since DNA is a highly negatively charged polyelectrolyte, electrostatic forces make a decisive contribution to chromatin formation and require the histones, particularly histone tails, to carry a significant positive charge. This also results in an essential role of mobile cations of the cytoplasm (K+, Na+, Mg2+) in regulating electrostatic interactions. Building on a previously successfully established bottom-up coarse-grained (CG) nucleosome model, we have developed a CG nucleosome array (chromatin fiber) model with the explicit presence of mobile ions and studied its conformational variability as a function of Na+ and Mg2+ ion concentration. With progressively elevated ion concentrations, we identified four main conformational states of nucleosome arrays characterized as extended, flexible, nucleosome-clutched, and globular fibers.
Measurement of divertor surface heat flux by infra-red thermographic inversion in ST40
Authors: Moscheni M. , Maartensson E. , Robinson M. , Marsden C. , Rengle A. , Scarabosio A. , Bunting P. , Gray T. K. , Janhunen S. , Vekshina E. , Zhang X.
Published: January 2025

Diagnostic tools for understanding the edge plasma behavior in fusion devices are essential. The main focus of the present work is to present the infra-red (IR) diagnostics installed on Tokamak Energy’s spherical tokamak (ST40) and the IR thermographic inversion tool, Functional Analysis of Heat Flux (FAHF). FAHF is designed for multi-2D thermographic inversions within the divertor tiles using the finite difference method and an explicit time stepping scheme. ST40’s re-entrant endoscope allows the acquisition of IR data with the highest available effective spatial resolution. With these data, FAHF calculates the plasma perpendicular heat flux density on the divertor—a crucial quantity for edge plasma analysis. Although FAHF demonstrates significant sensitivity to user-selected settings, precise heat flux values are recoverable by ensuring a sufficiently high resolution. Implications for the optimal resolution of both the code and the IR diagnostic system are discussed. FAHF’s simplifications are shown to give an error within 10% with respect to COMSOL Multiphysics® simulations. Finally, by means of comparison with Langmuir probe heat flux data, the accuracy of the FAHF heat fluxes is estimated to be satisfactory. As such, FAHF is proven to be a precise and accurate tool for IR thermographic inversions in ST40.
The further optimization and sensitivity analysis of the shape of the double-arc aeration facilities in gentle slope open channel
Authors: Dong Yuping , Li Guodong , Zhang Zhenchuan , Shen Guiying
Published: January 2025

Air entraining into water flow is one of the main technical measures to prevent cavitation damage in high-head discharge structures, and the most important issue is the optimization of the aerators shapes. Different body shapes result in different cavity characteristics, but there are currently few quantitative research results on the design of aerator shapes. Based on the design method of body parameters, this article uses orthogonal experimental design theory to conduct the further optimization and sensitivity analysis of the body shape of the double-arc aeration facility in a gentle slope open channel. Through range analysis and variance analysis, the influence effects and weights of the four body parameters, which are the deflector height, the offset height, water tongue drop point coefficient, and the ramp angle, acting on cavity characteristics such as cavity shape and ventilation capacity are obtained, and the most reasonable combination parameters for aeration facility are provided. This provides technical guidance for the precise design of aeration facility in practical engineering and promotes the quantification of aeration facility shape design.
An emulsion drop's impact on an inclined mesh: How far is the penetration possible?
Authors: Dutta Somen Kumar , Mandal Deepak Kumar
Published: January 2025

An emulsion drop's impact on inclined meshes is studied. The drop is observed to penetrate and spread along the mesh. The penetration reduces with a rise in inclination for a height and becomes limited at the highest angle for all heights. Capillary resistance outshines inertia, making the drop penetrate less and flow along the mesh. The maximum spread rises. The spread is compared with three existing models applicable to flat surfaces. One compares well for lower inclinations, whereas the other for higher ones. The study brings out the penetration limitation for an emulsion drop's impact on inclined meshes.
Progress in understanding the infrared spectrum of the H2O–O2 dimer
Authors: Barclay A. J. , McKellar A. R. W. , Moazzen-Ahmadi N.
Published: January 2025

Spectra of the weakly bound H2O–O2 dimer are studied in the region of the H2O ν2 band using a tunable quantum cascade laser to probe a pulsed supersonic slit jet expansion. These are the first gas-phase infrared spectra of H2O–O2 and among only a few such results for O2-containing complexes. Almost 100 infrared lines are assigned based on the ground state combination differences from the microwave spectrum of H2O–O2. These lines belong to a main fundamental band, plus four combination bands lying 2 to 5 cm−1 above the fundamental. All correspond to the ortho-H2O (I = 1) nuclear spin species. Interpretation of the observed rotational levels is discussed. The original microwave analysis conflicts with the infrared results but can be corrected by changing the sign of a term or, better still, by using a published theory for weakly bound open shell complexes. The combination bands suggest that analogous ground state bands should be observable in the millimeter wave range. Many infrared transitions remain unassigned, including another extensive band apparently centered at 1603 cm−1, and some of these are probably due to the para-H2O spin species (I = 0). Splittings due to the unpaired O2 electron spin (S = 1), due to large amplitude tunneling motions, and due to a-axis rotational motion all have similar magnitudes for H2O–O2, so the resulting energy levels will be heavily mixed and not amenable to simple modeling. Accurate theoretical predictions of these effects should be possible for obtaining an enhanced understanding of the observed spectra.