bluuebunny/crossref_metadata_2025 huggingface dataset:
The coherent magnetic field of the Milky Way halo, the Local Bubble, and the Fan region
Authors: Korochkin Alexander , Semikoz Dmitri , Tinyakov Peter
Published: December 2024

Context. A recent catalogue of the Faraday rotation measures (RMs) of extragalactic sources, together with the synchrotron polarisation data from WMAP and Planck, provide us with a wealth of information on the magnetic fields of the Galaxy. However, the integral character of these observables, together with our position inside the Galaxy, make the inference of the coherent Galactic magnetic field (GMF) complicated and ambiguous.

Aims. We combine several phenomenological components of the GMF – the spiral arms, the toroidal halo, the X-shaped field, and the field of the Local Bubble – to construct a new model of the regular GMF outside the thin disc.

Methods. We use the binned χ2 approach to fit the parameters of the model to the data. To have control over the relative contributions of the RM and polarisation data to the fit, we pay special attention to the estimation of errors in data bins. To this end, we developed a systematic method that is uniformly applicable to different data sets. This method takes into account individual measurement errors, the variance in the bin, and fluctuations in the data at angular scales that are larger than the bin size. This leads to a decrease in the errors and, as a result, to better sensitivity of the data to the model content. We cross checked the stability of our method with the new LOFAR data, which have very small errors on the measurements of individual sources.

Results. We find that the four components listed above are sufficient to fit both the RM and polarisation data over the whole sky with only a small fraction masked out. Moreover, we have achieved several important improvements compared to previous approaches. Due to our location inside of the Local Bubble, our model does not require the introduction of striated fields. For the first time, we show that the Fan region can be modelled as a Galactic-scale feature. The pitch angle of the magnetic field in our fit converges to a value of around 20 degrees. Interestingly, this value is very close to the direction of the spiral arms inferred recently from Gaia data on upper-main sequence stars.
Asymptotic-preserving hybridizable discontinuous Galerkin method for the Westervelt quasilinear wave equation
Authors: Gómez Sergio , Meliani Mostafa
Published: December 2024

We discuss the asymptotic-preserving properties of a hybridizable discontinuous Galerkin method for the Westervelt model of ultrasound waves. More precisely, we show that the proposed method is robust with respect to small values of the sound diffusivity damping parameter δ by deriving low- and high-order energy stability estimates, and a priori error bounds that are independent of δ. Such bounds are then used to show that, when δ → 0+, the method remains stable and the discrete acoustic velocity potential ψh(δ) converges to ψh(0), where the latter is the singular vanishing dissipation limit. Moreover, we prove optimal convergence rates for the approximation of the acoustic particle velocity variable υ=∇ψ. The established theoretical results are illustrated with some numerical experiments.
Approximation algorithms for the integrated path and bin packing problem
Authors: Li Weidong , Sun Ruiqing
Published: December 2024

In this paper, we consider the integrated path and bin packing problem, which to use the minimum number of unit-size bins to packing the arcs on the path between two specific vertices in a given directed graph. We propose a 3/2-approximation algorithm and an asymptotic polynomial time approximation scheme.
Enhancing the Accuracy of Intrusion Detection Systems by Reducing the Rates of False Negatives Through Using XG-boost and Optimization Algorithm
Authors: Saud Abd Noor , Karoui Kamel , Ghassan Abdulkareem Mohammed
Published: December 2024

Intrusion Detection Systems (IDSs) are highly essential in network infrastructure safeguarding through the detection and mitigation of the malicious activities. The high false negative percentages, occurring in the case where actual attacks aren’t identified, is a recurring difficulty in IDS implementation. Which poses significant security risks. The purpose of the present study is proposing an enhanced IDS model combining strong points of XGBoost, a highly effective gradient boosting algorithm, with Cat Swarm Optimization (CSO) algorithm for the purpose pf decreasing the number of the false negative cases and improving the overall accuracy of detection. Because XGBoost is well-known due to its exceptional scalability and performance in the tasks of classification, it represents an optimal option for the management of network traffic data intricacies. The algorithm that is referred to as the CSO has been designed for maximizing hyperparameters that are related to XGBoost model through drawing inspiration from natural cat behaviors. The performance of the CSO has been exceptionally well in the global challenges of optimization, guaranteeing that IDS will be functioning at the most effective configuration. The proposed approach has been subjected to a stringent evaluation using benchmark data-set, demonstrating a considerable reduction in numbers of the false negative cases in comparison with conventional methods of the IDS . Not only does the upgraded IDS enhance the detection accuracy for a wide variety of cyberattacks, yet it maintains a low false positive rate, which is essential for minimizing disruptions to normal network activities. When it comes to the actual deployment of IDS in real-world circumstances, where both security and operational efficiency are of the utmost importance, this balanced performance is crucial.

This research suggests and tests an improvement strategy for the XGboost model using cat swarm optimization in network intrusion detection. After we processed the imbalanced data, then the attacks have been redistributed in a way that includes the names of the sub-attacks within the main attacks ensure good and clear detection in the next step. Following that, we trained, tested and evaluated the optimum model using the test set. The improved XGboost model outperformed the non-optimized model, which had precision of 86.5%, accuracy equal to 84.1%, and an F1-score of 84.1%. The experimental results demonstrated that the improved XGboost model has good performance in terms of recall rate, accuracy, and average accuracy. It showed an accuracy equal to 0.98 with Precision of 97.8% and an F1-score of 97.7%, while lowering the FN ratio as indicated by the findings section's confusion matrix.
Efficacy and Tolerability of Lacosamide in Pediatric and Young Adult Epilepsy Patients with Severe Motor and Intellectual Disabilities
Authors: Ishikawa Nobutsune , Suzuki Shin , Komori Ryota , Izumo Hiroki , Goda Satoshi , Tsuboi Ayana , Jinno Kazuhiko
Published: December 2024

Objective Epilepsy is common among patients with severe motor and intellectual disabilities (SMID) patients, often taking a prolonged and intractable course. Lacosamide (LCM) is widely used to treat epilepsy in both adults and children. We assess the efficacy and tolerability of LCM among pediatric and young adult epilepsy patients with SMID who suffer from intractable seizures.

Methods This retrospective analysis reviewed the medical records of SMID patients undergoing LCM treatment for more than a year. The study included 24 patients (14 males) aged 3 to 29 years. Epilepsy was classified as focal in 17 patients, generalized in 4 patients, and combined generalized and focal in 3 patients.

Results The retention rates were 70.8%, 65%, and 52.9% at 1, 2, and 3 years after LCM initiation, respectively. The 50% responder rate (achieving >50% seizure reduction) for LCM treatment was 50%, with two patients experiencing complete seizure control (absence of seizures for 6 months before the follow-up visit). The 50% responders included a higher proportion of patients with focal epilepsy (58.8%) compared to those with generalized epilepsy (25.0%). Treatment-emergent adverse events (TEAEs) included somnolence in five patients and nausea in two patients. TEAEs, particularly nausea, developed within 1 month after treatment initiation in two patients, leading to LCM discontinuation.

Conclusion LCM demonstrated good efficacy for intractable epilepsy in pediatric and young adult SMID patients. It was generally well-tolerated, resulting in a favorable retention rate. LCM emerged as a useful antiseizure medication for epilepsy treatment in pediatric and young adult SMID patients.
Photodriven Site-Selective Deuteration of Pyridyl Ketones with Deuterium Oxide
Authors: Li Yanzhong , Dong Kaiwu , Tian Wen-Qiang , Shen Chaoren
Published: December 2024

In this work, a photodriven phosphine/D2O-mediated method for the reductive deuteration of pyridyl ketones was developed. By regulating the reaction conditions, site-selective deuteration of pyridyl diketones was achieved with high deuterium-incorporation rates.
Homeopathic Management of Bulky Uterus with Uterine Fibroid in a 40-year-old Patient: An Evidence-Based Case Report
Authors: Wadhwa Bharti , Kureel Shweta Singh
Published: December 2024

Background Uterine fibroids are benign gynecological tumours that arise in the uterine smooth muscle tissue and are characterized by the production of excessive quantities of extracellular matrix. Various therapeutic options, from medical management to surgical intervention, exist for uterine fibroids, for which homeopathy has emerged as a promising therapeutic option in patient-centered care.

Case History A 40-year-old woman presented with complaints of heavy menstrual bleeding, with pain in the pelvic region and back. She was diagnosed as a case of bulky uterus with uterine fibroid. The patient opted for homeopathic management and was prescribed Thuja occidentalis based on individualization, miasmatic analysis and repertorial totality.

Results After treatment, there was regression in size of the fibroid within 5 months, with complete resolution and restoration of the uterus to normal size within 9 months. Changes were validated through ultrasonography, which added objective evidence to the positive outcome. The Modified Naranjo Criteria for Homeopathy (MONARCH) inventory total score was +9, which indicated causal attribution of clinical outcome to the homeopathic intervention.

Conclusion This case study has illustrated the clinical benefits of homeopathy in the management of a patient with uterine fibroids, reaffirming the need for further research to explore its value as a therapeutic option for individuals seeking alternative or complementary approaches for appropriate medical conditions.
Beverage-Induced Surface Changes in Biomimetic Dental Resin Composite: AFM and Bacterial Analysis
Authors: Basheer Rasha R. , Hamza Nermeen K.
Published: December 2024

Objective Continuous advancements in composite resin materials have revolutionized and expanded its clinical use, improving its physical and mechanical properties. Attaining and retaining surface texture and gloss are crucial for the long-term durability of the composite resin material. This study investigated the supra-nanospherical filler composite material compared with different composite resin materials immersed in different beverages. The study evaluated their surface roughness and subsequent adhesion of bacteria.

Materials and methods A total of 144 specimens were made, using Teflon mold from different composite materials. Eighty-four specimens were used for surface roughness testing, using four different resin composite materials, Tetric N-Ceram (Ivoclar Vivadent, Schaan, Liechtenstein), Multichrome (Harvard Dental, Germany), Filtek Z350 XT (3M ESPE, Minnesota, United States), and Palfique LX5 (Tokuyama Dental Corporation, Taitō-Ku, Tokyo, Japan; n = 21). They were further subdivided into three subgroups according to the immersion solution (n = 7) for Monster, Gatorade, and deionized water, which served as the control group. Surface roughness values were tested via atomic force microscopy (AFM). Then, for biofilm testing the bacterial count was performed on the remaining 60 composite specimens from the four tested composite materials (n = 15), that were subdivided randomly based on the immersion solutions into three subgroups (n = 5).

Statistical analysis Data were collected and statistically analyzed using the Kruskal–Wallis test followed by Dunn's post hoc test with Bonferroni's correction (p ≤ 0.05). The intergroup comparison showed a significant difference among different composite materials (p < 0.05), with the Multichrome showing the highest roughness values. Also, there was a significant difference between all composite materials with different beverages, with Palfique LX5 showing the lowest average roughness (Ra) values. All studied materials' average surface roughness, however, remained below the crucial Ra value of 0.2 μm. For the bacterial count, there was a significant difference between different materials in different beverages (p < 0.05), with Z350 XT and Palfique LX5 showing the lowest bacterial count.

Conclusion Supra-nanospherical composite (Palfique LX5) exhibited better resistance to different beverage challenges regarding surface roughness, while nanohybrid composite (Z350) showed the least bacterial adherence.
Rare Mandibular Surgical Ciliated Cysts: First Case Reported in a Brazilian
Authors: Lopes-Santos Gabriela , Filho Hugo Nary , Oliveira Denise Tostes
Published: December 2024

This reported case represents the first well-documented mandibular surgical ciliated cyst, following orthognathic surgery consisting of a combination of Le Fort I bimaxillary and sagittal osteotomy concomitantly with genioplasty, reported in a Brazilian patient. A case of 43-year-old female presenting a mandibular surgical ciliated cyst after 16 years of an orthognathic surgery, consisting of a combination of Le Fort I osteotomy and genioplasty, is reported. The cystic lesion was enucleated, and the histopathological analysis showed a cystic cavity lined by pseudostratified columnar respiratory-type epithelium presenting ciliated and mucous cells supported by fibrous connective tissue without inflammation. The diagnosis established was a mandibular surgical cilited cyst. Then, for diagnosis of mandibular surgical ciliated cyst is essential the association of clinical/imagological and histopathological features with the patient' past history showing evidence of previous surgery in the mandible concomitant with the maxilla.
The Effect of Novel Laser-Activated Bleaching Protocols on the Color Change of Non-Vital Anterior Teeth: An In Vitro Study
Authors: EL Zayat Inas , Hamid Mohamed Bahgat Abdel , Farouk Ahmed Tarek , El-Damanhoury Hatem Mostafa
Published: December 2024

Objective This study compares the color change of non-vital anterior teeth after laser-activated bleaching and conventional walking bleaching technique.

Materials and Methods Sixty extracted teeth were endodontically treated, stained in a black tea solution, and the baseline shade was measured using a spectrophotometer (Easyshade, VITA). Bleaching was done using either: internal bleaching with 35% H2O2 (Opalescence Endo) and then tooth sealed for 5 days (Gr1), 35% H2O2 (JW Next) for 7 minutes (Gr2), internal and external bleaching for 7 minutes (Gr3), diode laser-activated internal bleaching for 30 seconds (940 nm, continuous wave, 2 W, noncontact mode, 300 um, non-initiated tip), wait for 7 minutes, second laser application for 30 seconds, tooth sealed for 5 days (Gr4), diode laser-activated internal bleaching for 24 hours (Gr5), or diode laser-activated internal and external bleaching for 24 hours (Gr6) (n = 10). The color change (ΔE00) was measured and data were analyzed using one-way analysis of variance followed by Tukey post hoc test (a = 0.05). The inner dentin of the samples was inspected using scanning electron microscopy.

Results All the tested bleaching techniques were able to change the color. All the laser-activated bleaching protocols, namely, Gr4, Gr5, and Gr6, showed higher mean ΔE00 values than the non-laser-activated bleaching Gr2 and Gr3 (p < 0.05) and were statistically similar (p > 0.05) to the control group Gr1. Laser-activated bleaching caused surface modification and dentinal tubule opening.

Conclusion All the tested laser-activated bleaching protocols showed faster and more efficient color change, comparable to the conventional 5-day walking bleaching protocol.
Quasilocal vibrations and crossing splittings in the spectrum of strongly anisotropic chain crystals containing heavy impurity atoms
Authors: Bercha D. M. , Botvinko M. N. , Germanskaya L. Yu. , Ivanov M. A.
Published: December 2024

It is shown that in a strongly anisotropic crystal, due to the anisotropy of the interatomic potential and the transverse modulus in the spectral region where the dispersion curve exhibits significant three-dimensional character, there arise quasilocal vibrations. The characteristic concentration c0 at which a crossing rearrangement of the spectrum near the quasilocal vibration takes place for the longitudinal branches is somewhat lower than for the transverse, but in both cases it is larger than for an isotropic crystal.
Strength of a vortex lattice
Authors: Tkachenko V. K.
Published: December 2024

The Kronecker formula is used to calculate the vibration spectrum and free energy of a vortex lattice in rotating superfluid helium. The minimum lattice deformation at which the lattice loses its stability is also found.
Motion of a bound pair of multielectron dimples
Authors: Krasnyĭ Yu. P. , Mikho V. V.
Published: December 2024

Calculations are made of the dynamic and viscosity characteristics that describe different forms of motion by a bound pair of multielectron dimples along the surface of liquid helium. The frequency and damping increment of natural frequencies are found as functions of the external electrostatic field.
Induction of superconductivity by an electric field in material with a low carrier density
Authors: Shapiro B. Ya.
Published: December 2024

An electric field perpendicular to the surface of a semimetal or semiconductor (not necessarily superconducting) causes the carrier density to increase near the surface and this in turn gives rise to an increase in the magnitude of the electron–electron interaction and, consequently, the appearance of a nonuniform surface superconducting state. The critical temperature and the magnetic field of such superconducting states can attain considerable values because of the weak influence of the “proximity effect,” which usually decreases the critical parameters of a narrow superconducting layer in a nonsuperconducting, metallic medium.
Current-carrying state of two-dimensional superconductors
Authors: Ivanchenko Yu. M. , Kozinskaya A. I. , Medvedev Yu. V.
Published: December 2024

The kinetics of the evolution of vortex molecules (vortex-antivortex pairs) in a two-dimensional superconductor is studied. The rate of dissociation of such pairs is found and the contribution of dissociating molecules to the resistance of the sample is determined. The result can be used to obtain information on the nature of recombination processes occurring in the vortex “plasma.” A system of equations determining the dependence of the Kosterlitz–Thouless “transition temperature” T2D on the superfluid velocity vs is obtained.
Interaction of two distributed Josephson SNS junctions, caused by the penetration of a longitudinal electric field
Authors: Kaplunenko V. K.
Published: December 2024

The interaction of two distributed Josephson SNS junctions in the case when the distance between them is comparable to the penetration depth of the longitudinal electric field in the superconductor is studied experimentally and theoretically. The experimental data obtained show that the external magnetic field affects the size of the region of phase-locking (the data are explained theoretically with the help of truncated equations, obtained for a distributed junction in the limit of high voltages). It is shown theoretically that the observed dependences of the size of the region of phase-locking on the magnetic field are linked with the fact that the junctions are distributed.
Generation of combination-frequency sound harmonics in conductors
Authors: Kopasov A. P.
Published: December 2024

The generation of combination-frequency harmonics of longitudinal sound waves in conductors is investigated in the case where all the wavelengths are much smaller than the electron mean free path. It is shown that when the primary waves propagate in the same direction, resonant (moving in phase with the sound waves) electrons can provide the main contribution to the nonlinear response characterizing difference-frequency generation, whereas the sum-frequency nonlinear response is associated with nonresonant electrons and coincides with the static response. Difference-frequency generation is considerably more efficient than sum-frequency generation in the given situation.
Light scattering by exchange magnons in multisublattice antiferromagnets in a magnetic field
Authors: Pashkevich Yu. G. , Sobolev V. L. , Fedorov S. A.
Published: December 2024

Raman light scattering in the antiferromagnet CuCI2·2H2O is discussed in terms of a four-sublattice model. The treatment is carried out for H∥x and T = 0. We study the magnetic field dependence of the scattered intensity and discuss the possibility of observing the exchange branches via Raman scattering.
Quasilocal levels in tunnel junctions
Authors: Genenko Yu. A. , Ivanchenko Yu. M.
Published: December 2024

The exact solution of the problem of the conductivity of a tunnel junction in the tunneling Hamiltonian method is studied. It is shown that quasilocal levels appear in junctions with high transmission. The concomitant restructuring of the spectrum results in the fact that perturbation theory is no longer applicable. The current–voltage characteristics of junctions with different transmission are calculated for narrow-band conductors.
Experimental study of the generation current density in superconducting tin films
Authors: Churilov G. E. , Svetlov V. N. , Dmitriev V. M.
Published: December 2024

Generation of high-frequency oscillations in superconducting films in the resistive state was observed at a definite de current density, which is different for “narrow” and “wide” samples. The criterion that distinguishes these two cases is a width of the order of the penetration depth of the longitudinal electric field.
Temperature and field dependences of the energy gap in the AFMR spectrum of ErFeO3
Authors: Dan’shin N. K. , Kovtun N. M. , Sdvizhkov M. A.
Published: December 2024

The effect of the temperature and magnetic fields with different orientations on the size of the energy gap of a magnetic resonance at a low-temperature phase transition is discussed.
Coherent kinetics and thermodynamics of twinned conductive films
Authors: Kadigrobov A. M. , Koshkin I. V.
Published: December 2024

It is shown that a slab with a twin can have an N-shaped current–voltage characteristic and can have current and voltage oscillations excited in it with a frequency of 109−1010 sec−1. The deHaas–van Alphen effect is found to have specific features that significantly facilitate its experimental observation. “Grazing” electrons are shown to be almost totally reflected from the twin boundary and in the general case the scattering is a two-channel process.
Collective oscillations of the order parameter in superconductors with local pairs
Authors: Beloborod’ko S. I. , Kulik I. O.
Published: December 2024

Collective oscillations of the order parameter in superconductors with local singlet pairing are studied. It is shown that for an uncharged superfluid liquid there exist oscillations with an acoustic spectrum, analogous to the Anderson–Bogolyubov oscillations in the BCS theory. Taking into account the long-range part of the Coulomb interaction gives a plasma threshold in the spectrum of oscillations. If, however, there exists, in addition to a narrow band, whose electrons form local pairs, a wide conduction band, then the spectrum once again becomes gapless.
Electromagnetic excitation of sound in metals in a tilted magnetic field at low temperatures
Authors: Fal’ko V. L.
Published: December 2024

A solution is obtained for the problem of the electromagnetic excitation of sound in metals and semimetals at low temperatures in a tilted magnetic field under the conditions of strong spatial inhomogeneity, such that qR ≫ 1 (R is the cyclotron radius of the conduction electron, q = ω/s, ω is the frequency of the electromagnetic wave, and s is the sound velocity). It is shown that the amplitude of the excited sound increases sharply when the magnetic field H deviates from the perpendicular to the direction of sound propagation, qH = 0, by an angle φ = φK; this is the tilt effect (sin φK = s/υ, where υ is the velocity of an electron from the neighborhood of the reflectance point on the Fermi surface). For φK < φ ≪ π/2 the amplitude exhibits oscillations induced by electrons of nonextremal cross sections of the Fermi surface. The influence of the type of reflection of electrons from the surface of a metal is discussed.
Low-temperature vibrational characteristics of surface atoms in the presence of a weakly coupled impurity layer
Authors: Syrkin E. S. , Gel’fgat I. M.
Published: December 2024

The effect of a weakly coupled impurity surface monolayer on the phonon spectrum, root mean square displacements and on the melting temperature of the near-surface layers has been investigated. In particular, a sharp low-temperature maximum in the temperature dependent part of the rms displacements of the surface atoms was found.
Contribution to the theory of spin waves in itinerant ferromagnets
Authors: Povzner A. A.
Published: December 2024

The method developed here for calculating the dynamic susceptibility of itinerant ferromagnets takes into account the effect of spin fluctuations on the electron and magnon spectra of the materials. Using the formula derived for the susceptibility, we study some distinctive features of the spin-wave spectra of weak itinerant ferromagnets with low Curie temperatures.
Effect of impurities on thermally activated and quantum creep of zinc single crystals
Authors: Zagoruĭko L. N. , Natsik V. D. , Soldatov V. P.
Published: December 2024

The low-temperature creep of zinc single crystals with various contents of silver and lead impurities has been investigated. A detailed thermal-activation analysis was made of the experimental data to establish the type and characteristics of the barriers to basal slip and to determine the quantum mechanisms by which dislocations surmount these barriers. The role of effective barriers to dislocations in the alloys studied is shown to be played by pair complexes and not by single impurity atoms, i.e., low-temperature creep is controlled by sufficiently strong local barriers. Below T ≲ 30° K such barriers are surmounted as a result of the quantum motion of dislocation segments.
Magnetoresistance of tungsten single-crystals with surface defects
Authors: Cherepanov A. N. , Marchenkov V. V. , Startsev V. E. , Volkenshtein N. V. , Glin’ski M.
Published: December 2024

The effect of a defective surface layer on the magnetoresistance of tungsten single-crystals with ρ293.2/ρ4.2 = 80,000 has been studied in the temperature range from 4.2 to 50° K in magnetic field up to 150 kOe. It is shown that a defective crystal surface leads to a large change in the magnetoresistance anisotropy, in the field and temperature dependences, and also to a redistribution of a direct electric current within the crystal and to its gathering into the subsurface defect layer.
Investigation of the alpha particle-induced electron–ion temperature nonequilibrium burning process in inertial confinement fusion
Authors: Lin Weisheng , Zhang Huasen , He Bin , Cai Hongbo , Zhu Shaoping
Published: December 2024

The achievement of thermal nuclear burn at the National Ignition Facility represents a significant milestone in the field of fusion science and engineering. This study uses the double-temperature model to investigate the degree of alpha particle-induced electron–ion temperature nonequilibrium and the final burn fraction in the inertial confinement fusion (ICF) burn process. The time evolution of the burn process with typical inertial confinement fusion parameters reveals that the nonequilibrium degree shows a trend of initially decreasing and then increasing, with the final burn fraction in the double-temperature model being higher than that in the single-temperature model. The investigation of the dependence of the burn fraction on initial parameters reveals that the burn fraction of the single-temperature and double-temperature models intersect at a characteristic ion temperature of about 45 keV, which is attributed to the dependence of the fusion rate on the ion temperature. The relationship between the nonequilibrium factor δNf and burn fraction fb in the electron heat conduction loss-dominant region satisfies (δNf−1)/fb≈ const. Furthermore, the tritium fraction required to achieve the maximum burn fraction decreases as the initial areal density increases when the initial temperature is equal to 5 keV and the fuel is ignited. With different deuterium–tritium ratios, the extended burn fraction formula fits both the single-T and the double-T model results well under typical ICF parameters.
Quantum oscillations of the magnetic properties in Mn-diluted (Mn, Ga)4C alloys
Authors: Liang Yinghua , Zhang Zhong , Zhou Tianhong , Park Jihoon , Choi Chul-Jin , Wu Qiong , Ge Hongliang , Si Pingzhan
Published: December 2024

High purity antiperovskite-type Mn3−xGa1+xC (0 < x ≤ 0.3) alloys with varied Mn-concentration were prepared by using the solid state reaction method. The Curie temperature and the magnetization of Mn3−xGa1+xC were observed to oscillate as a function of x. The oscillations of the magnetic properties were ascribed to the increasing distance between Mn–Mn atoms due to dilution of the Mn atoms in the Mn3−xGa1+xC lattice with increasing x and the oscillation of the lattice parameters. The period of the oscillations in the current Mn-diluted alloys is much smaller than that observed in magnetic films, indicating fundamentally different mechanisms from the traditional oscillations of physical observables as a function of inverse magnetic field in metals/semi-metals/insulators or as a function of thickness of magnetic/nonmagnetic layer in multilayered magnetic films. This work opens new perspectives for the oscillations of physical observables in novel magnetic materials.
Realized stable BP-N at ambient pressure by phosphorus doping
Authors: Chen Guo , Zhang Chengfeng , Zhu Yuanqin , Cao Bingqing , Zhang Jie , Wang Xianlong
Published: December 2024

Black-phosphorus-structured nitrogen (BP–N) is an attractive high-energy-density material. However, high-pressure-synthesized BP-N will decompose at low pressure and cannot be quenched to ambient conditions. Finding a method to stabilize it at 0 GPa is of great significance for its practical applications. However, unlike cubic gauche, layered polymeric, and hexagonal layered polymeric nitrogen (cg-N, LP-N, and HLP-N), it is always a metastable phase at high pressures up to 260 GPa, and decomposes into chains at 23 GPa. Here, on the basis of first-principles simulations, we find that P-atom doping can effectively reduce the synthesis pressure of BP-N and maintain its stability at 0 GPa. Uniform distribution of P-atom dopants within BP-N layers helps maintain the structural stability of these layers at 0 GPa, while interlayer electrostatic interaction induced by N–P dipoles enhances dynamic stability by eliminating interlayer slipping. Furthermore, pressure is conducive to enhancing the stability of BP-N and its doped forms by suppressing N-chain dissociation. For a configuration with 12.5% doping concentration, a gravimetric energy density of 8.07 kJ/g can be realized, which is nearly twice that of trinitrotoluene.
Topological confinement by a membrane anchor suppresses phase separation into protein aggregates: Implications for prion diseases
Authors: Gogte Kalpshree , Mamashli Fatemeh , Herrera Maria Georgina , Kriegler Simon , Bader Verian , Kamps Janine , Grover Prerna , Winter Roland , Winklhofer Konstanze F. , Tatzelt Jörg
Published: December 2024

Protein misfolding and aggregation are a hallmark of various neurodegenerative disorders. However, the underlying mechanisms driving protein misfolding in the cellular context are incompletely understood. Here, we show that the two-dimensional confinement imposed by a membrane anchor stabilizes the native protein conformation and suppresses liquid–liquid phase separation (LLPS) and protein aggregation. Inherited prion diseases in humans and neurodegeneration in transgenic mice are linked to the expression of anchorless prion protein (PrP), suggesting that the C-terminal glycosylphosphatidylinositol (GPI) anchor of native PrP impedes spontaneous formation of neurotoxic and infectious PrP species. Combining unique in vitro and in vivo approaches, we demonstrate that anchoring to membranes prevents LLPS and spontaneous aggregation of PrP. Upon release from the membrane, PrP undergoes a conformational transition to detergent-insoluble aggregates. Our study demonstrates an essential role of the GPI anchor in preventing spontaneous misfolding of PrP
C
and provides a mechanistic basis for inherited prion diseases associated with anchorless PrP.
In situ architecture of a nucleoid-associated biomolecular co-condensate that regulates bacterial cell division
Authors: Xu Peng , Schumacher Dominik , Liu Chuan , Harms Andrea , Dickmanns Marcel , Beck Florian , Plitzko Jürgen M. , Baumeister Wolfgang , Søgaard-Andersen Lotte
Published: December 2024

In most bacteria, cell division depends on the tubulin-homolog FtsZ that polymerizes in a GTP-dependent manner to form the cytokinetic Z-ring at the future division site. Subsequently, the Z-ring recruits, directly or indirectly, all other proteins of the divisome complex that executes cytokinesis. A critical step in this process is the precise positioning of the Z-ring at the future division site. While the divisome proteins are generally conserved, the regulatory systems that position the Z-ring are more diverse. However, these systems have in common that they modulate FtsZ polymerization. In
Myxococcus,
PomX, PomY, and PomZ form precisely one MDa-sized, nonstoichiometric, nucleoid-associated assembly that spatiotemporally guides Z-ring formation. Here, using cryo-correlative light and electron microscopy together with in situ cryoelectron tomography, we determine the PomXYZ assembly’s architecture at close-to-live conditions. PomX forms a porous meshwork of randomly intertwined filaments. Templated by this meshwork, the phase-separating PomY protein forms a biomolecular condensate that compacts and bends the PomX filaments, resulting in the formation of a selective PomXYZ co-condensate that is associated to the nucleoid by PomZ. These studies reveal a hitherto undescribed supramolecular structure and provide a framework for understanding how a nonstoichiometric co-condensate forms, maintains number control, and nucleates GTP-dependent FtsZ polymerization to precisely regulate cell division.
Higher-order transient membrane protein structures
Authors: Zhang Yuxi , Mazal Hisham , Mandala Venkata Shiva , Pérez-Mitta Gonzalo , Sondoghdar Vahid , Haselwandter Christoph A. , MacKinnon Roderick
Published: December 2024

This study shows that five membrane proteins—three GPCRs, an ion channel, and an enzyme—form self-clusters under natural expression levels in a cardiac-derived cell line. The cluster size distributions imply that these proteins self-oligomerize reversibly through weak interactions. When the concentration of the proteins is increased through heterologous expression, the cluster size distributions approach a critical distribution at which point a phase transition occurs, yielding larger bulk phase clusters. A thermodynamic model like that explaining micellization of amphiphiles and lipid membrane formation accounts for this behavior. We propose that many membrane proteins exist as oligomers that form through weak interactions, which we call higher-order transient structures (HOTS). The key characteristics of HOTS are transience, molecular specificity, and a monotonically decreasing size distribution that may become critical at high concentrations. Because molecular specificity invokes self-recognition through protein sequence and structure, we propose that HOTS are genetically encoded supramolecular units.
CryoSeek II: Cryo-EM analysis of glycofibrils from freshwater reveals well-structured glycans coating linear tetrapeptide repeats
Authors: Wang Tongtong , Huang Wenze , Xu Kui , Sun Yitong , Zhang Qiangfeng Cliff , Yan Chuangye , Li Zhangqiang , Yan Nieng
Published: December 2024

Despite the recent breakthrough in structure determination and prediction of proteins, the structural investigation of carbohydrates remains a challenge. Here, we report the cryo-EM analysis of a glycofibril found in the freshwater in the Tsinghua Lotus Pond. The fibril, which we name TLP-4, is made of a linear chain of tetrapeptide repeats coated with >4 nm thick glycans. In each repeat, two glycans are O-linked to a 3,4-dihydroxyproline and another glycan attaches to the adjacent Ser or Thr. The fibril structure is entirely maintained through glycan packing. Bioinformatic analysis confirms the conservation of the TLP-4 repeats across species, suggesting the existence of a large number of glycofibrils to be discovered. Our findings not only provide valuable insights into the structural roles of glycans in bio-assemblies but also demonstrate the potential of our recently formulated research strategy of CryoSeek to find bioentities and establish prototypes for structural studies of carbohydrates.
A truncated isoform of Connexin43 caps actin to organize forward delivery of full-length Connexin43
Authors: Baum Rachel , Nguyen Vu D. , Maalouf Mario , Shimura Daisuke , Waghalter Miriam , Srapyan Sargis , Jin Qianru , Kuzmanovich Lucas , Gaffney Adelaide T. , Bell Bridger R. , Xiao Shaohua , Palatinus Joseph A. , Kléber André G. , Grintsevich Elena E. , Hong TingTing , Shaw Robin M.
Published: December 2024

While membrane proteins such as ion channels continuously turn over and require replacement, the mechanisms of specificity of efficient channel delivery to appropriate membrane subdomains remain poorly understood. GJA1-20k is a truncated Connexin43 (Cx43) isoform arising from translation initiating at an internal start codon within the same parent GJA1 mRNA and is requisite for full-length Cx43 trafficking to cell borders. GJA1-20k does not have a full transmembrane domain, and it is not known how GJA1-20k enables forward delivery of Cx43 hemichannels. Here, we report that a RPEL-like domain at the C terminus of GJA1-20k binds directly to actin and induces an actin phenotype similar to that of an actin-capping protein. Furthermore, GJA1-20k organizes actin within the cytoplasm to physically outline a forward delivery pathway for microtubule-based trafficking of Cx43 channels to follow. In conclusion, we find that the postal address of membrane-bound Cx43 channel delivery is defined by a separate protein encoded by the same mRNA of the channel itself.
Bias voltage controlled inversions of tunneling magnetoresistance in van der Waals heterostructures Fe3GaTe2/hBN/Fe3GaTe2
Authors: Zhang Lihao , He Miao , Wang Xiaoyu , Zhang Haodong , Han Keying , Liu Yonglai , Zhang Lei , Cheng Yingchun , Pan Jie , Qu Zhe , Wang Zhe
Published: December 2024

We report the bias voltage-controlled inversions of tunneling magnetoresistance (TMR) in magnetic tunnel junctions composed of Fe3GaTe2 electrodes and hBN tunneling barrier, observed at room temperature. The polarity reversal of TMR occurs consistently at around 0.625 V across multiple devices and temperatures, highlighting the robustness of the effect. To understand this behavior, we developed a theoretical model incorporating spin-resolved density of states (DOS) at high energy levels. By adjusting the DOS weighting at different k-points to account for misalignment between the crystal structure of electrodes in experimental devices, we improved agreement between experimental and theoretical inversion voltages. Our results provide valuable insight into the voltage-controlled spin injection and detection in two-dimensional magnetic tunnel junctions, with implications for the development of energy-efficient spintronic devices.
Nanowrinkle waveguide in graphene for enabling secure Dirac fermion transport
Authors: Jun Seunghyun , Jung Myung-Chul , Myoung Nojoon
Published: December 2024

Localized states in graphene have garnered significant attention in quantum information science due to their potential applications. Despite graphene’s superior transport and electronic properties compared to other semiconductors, achieving nanoscale confinement remains challenging due to its gapless nature. In this study, we explore the unique transport properties along nanowrinkles in monolayer graphene. We demonstrate the creation of a one-dimensional conduction channel by alternating pseudomagnetic fields along the nanowrinkle, enabling ballistic Dirac fermion transport without leakage. This suggests a feasible method for secure quantum information transfer over long distances. Furthermore, we extend our analysis to bent nanowrinkles, showcasing well-guided Dirac fermion propagation unless the bent angle is sufficiently large. Our demonstration of the nanowrinkle waveguide in graphene introduces a novel approach to controlling Dirac fermion transport through strain engineering, for quantum information technology applications.
Optimizing electrical and mechanical properties via intermetallics distribution in Cu–Al spot welding
Authors: Shi Shih-Chen , Weng Wei-Chieh , Rahmadiawan Dieter
Published: December 2024

This study investigates the role of barrier layers in minimizing intermetallic formation during copper–aluminum spot welding to improve mechanical properties and electrical conductivity. Results show that introducing barrier layers, such as nickel and zinc, reduces hardness as expected but leads to complex effects on tensile strength and electrical conductivity. Two key mechanisms are identified: diffusion blocking, which limits intermetallics formation, and energy absorption modulation during welding, which influences strength based on barrier layer thickness. Nickel barriers significantly increase tensile strength, peaking at 15 μm, while zinc barriers reach maximum effectiveness at 20 μm. Beyond optimal thickness, incomplete welding penetration causes a decline in strength. Al2Cu is identified as the primary intermetallic compound formed during direct copper–aluminum welding. With nickel barriers, Al2Cu is dispersed, suggesting better diffusion control. Zinc barriers, on the other hand, lead to the formation of Al4Cu9 and Al2Cu, both dispersed similarly within the weld nucleus. Higher welding currents (1200 A) yield stronger welds than lower currents (1100 A), highlighting the importance of welding parameters in optimizing mechanical performance. Electrical resistivity is influenced by intermetallic layers and defects like cracks or voids at the interface, impacting overall electrical performance. This study provides insights into how barrier layers and welding conditions can be optimized to enhance the mechanical and electrical performance of copper–aluminum spot welds.
Optical characterization of actively cooled switching arcs in SF6 alternatives
Authors: Engelbrecht J T , Kumari D , Franck C M
Published: December 2024

A detailed study of the evolution of transient arc properties in SF6 alternative gas mixtures was carried out on an experimental puffer circuit breaker. Thermal interruption tests were performed in several CO2-based mixtures under short-line fault-like current and voltage stresses, with the test device providing a similar arc environment and interruption performance to a commercial circuit breaker. The time evolution of arc properties including the radius, temperature, and electron density were investigated using high-speed imaging and optical emission spectroscopy techniques. These results were compared with simulation results from a simple 1-D, two-zone arc model. Spatially resolved measurements of the arc were obtained in the critical interruption regions of the nozzle, including the first reported 2D measurements of the temperature distribution during the interruption process in CO2. These measurements revealed a faster temperature decay in the nozzle throat, indicative of stronger cooling in this region compared to the upstream stagnation zone. Comparisons between the behavior of SF6 and its alternatives largely agreed with the model predictions, with lower temperatures and earlier temperature decay observed in SF6, followed by CO2-based mixtures, while air exhibited the highest temperatures and latest onset of temperature decay. No significant influence of oxygen content was observed on the maximum arc temperature of CO2 / O2 mixtures at currents above 500 A, where values ranging from 20 kK to 25 kK were typically observed.
Thermal plasma technology applied to the inertization process of the inorganic fraction of sewage sludge generated from municipal wastewater treatment plant
Authors: Busquet de Sant’Anna Junior Alvaro , Miranda Felipe de Souza , Paiva Moreira Junior Pedro William , da Cruz Antonio Carlos , Essiptchouk Alexei , Ferreira Antônio , Fuji Marcio , Petraconi Gilberto
Published: December 2024

This study investigates the thermal plasma pyrolysis process for inertizing the inorganic fraction of sewage sludge from municipal wastewater treatment plants. The aim is to assess its effectiveness in waste inertization. Lab-scale experiments were conducted to process the sludge thermally. Elemental composition analysis was done using x-ray fluorescence (XRF), thermogravimetry coupled with mass spectrometry (TGA-MS) and x-ray diffraction (XRD). The XRF analysis showed an initial composition of Si, Al, Fe, and Ca, corresponding to 86.8% of the inorganic matter of the sludge. TGA-MS analysis showed a significant mass loss between 200 and 650°C, corresponding to organic matter volatilization, methane conversion, and dehydrogenation of polymorphic silicon. XRD analysis revealed a dried sludge crystalline structure composed mainly by SiO2, CaCO3, and AlPO4, and after plasma treatment, the remaining composition of the slag was primarily SiO2 amorphous. Mass and energy balances, considering thermodynamic equilibrium and chemical reactions, are performed. The mass balance calculations identified the most probable composition of the sludge, and energy balance calculations determined a net energy requirement of 399 kWh for plasma inertization, with an additional 300 kWh to account for furnace losses. Solubility and leaching tests confirm the inert nature of the residue. Power requirements are estimated at 700 kW for processing 350 kg h−1 of decarbonized sludge. These findings are crucial for optimizing plasma inertization processes in wastewater treatment plants. This work presents a novel approach by combining a computational prediction for an industrial-scale plant with a direct experimental assessment of the plasma treatment process.