bluuebunny/crossref_metadata_2025 huggingface dataset:
Artroplastia total de rodilla en luxación inveterada de patela: Reporte de un caso
Authors: Vicuña Bernardita , Mendez Magdalena , Orrego Mario , Arteaga Matías
Published: December 2024

Introducción La luxación patelar inveterada (LPI) asociada a artrosis es un problema infrecuente y de difícil manejo, especialmente en pacientes con síndrome de Down (SD). La alteración crónica del funcionamiento patelofemoral (PF) debido a un severo mal alineamiento conduce a una progresiva destrucción articular que puede culminar en artrosis tricompartimental. Se han descrito distintas técnicas para su resolución, desde procedimientos en partes blandas hasta el uso de prótesis total de rodilla (PTR).

Presentación del caso Hombre de 29 años con SD consultó por un año de gonalgia derecha atraumática, asociado a episodios de derrame articular. Inicialmente, se diagnosticó como artritis séptica. El examen físico mostró hiperlaxitud (Beighton 8), marcha claudicante, LPI, genu valgo irreductible y artrosis tricompartimental con genu valgo de 13,3° a derecha. Se trató con una PTR y realineamiento del aparato extensor mediante alargamiento del retináculo lateral y avance del vasto medial oblicuo (VMO) con técnica de Insall. A los 8 meses postoperatorios, el paciente está sin dolor, sin nuevos episodios de luxación patelar y es independiente para las actividades básicas de la vida diaria.

Discusión Se trata de un caso complejo de gonartrosis e inestabilidad patelar asociado a genu valgo, en un paciente con SD e hiperlaxitud. Junto con la LPI, enfrentamos un valgo de 13,3° y artrosis tricompartimental. Se planificó una PTR primaria estabilizada posterior (PS) con posibilidad de mayor constricción intraoperatoria, junto con realineamiento de partes blandas. La literatura demuestra que este paso es esencial para restaurar la biomecánica PF y lograr buena funcionalidad.
The COVID-19 Pandemic's Impact on General Pediatric Ward Admissions: A Single-Center Study
Authors: AlEed Ashwaq , Alsalamah Abdullrahman , Alharbi Abdulaziz O. , Alrashedi Ahmad , Al-Nafeesah Abdullah , Al-Wutayd Osama , Al-Batanony Manal A.
Published: December 2024

Objective A decline in health care utilization and hospital admissions resulted from the coronavirus disease 2019 (COVID-19) pandemic, severely affecting many aspects of life. In this study, we sought to evaluate the pandemic impact on general pediatric admissions by comparing the 1-year prepandemic period.

Methods From the hospital records, all pediatric admissions from the beginning of March 2020 to the end of February 2021 and the corresponding period in 2019 to 2020 were included in this descriptive study.

Results A total of 4,179 hospitalizations met the study's inclusion criteria; 2,778 occurred before the pandemic and 1,401 occurred during the pandemic. The total pediatric hospitalizations decreased by 49.6% during the pandemic compared with before. Asthma (p-value < 0.001), acute bronchiolitis (p-value = 0.01), upper respiratory tract infections (p-value < 0.001), and delivery-related disorders (p-value = 0.01) all showed substantial significant decreases during the pandemic period compared with the prepandemic era.

Conclusion The decline in the overall hospitalization rate reflected the fear of contracting COVID-19 in an unsafe hospital environment. Concurrently, the incidence of communicable diseases fell due to pandemic-related lockdowns, hand hygiene issues, and school closures. While social distancing is highly recommended to protect children's health, public health officials must keep reminding parents not to defer necessary care since pediatric services remain accessible and unaffected during these difficult times.
Artropatía secundaria a inestabilidad glenohumeral anterior y análisis de las técnicas quirúrgicas: ¿Alguna influye en su aparición y progreso? Estado del arte
Authors: Melean Patricio , Koporcic Rade
Published: December 2024

El objetivo primario de esta revisión es describir cómo las diferentes técnicas quirúrgicas que existen para el tratamiento de la inestabilidad anterior de hombro influyen en el desarrollo de artropatía post luxación glenohumeral (ALGH), condición similar a la artrosis, que puede desarrollarse especialmente en pacientes con episodios recurrentes.

En estadios iniciales esta patología no produce mayores limitaciones funcionales, en estados más avanzados puede alterar significativamente las actividades de nuestros pacientes.

La cirugía post inestabilidad busca restaurar la estabilidad y prevenir la progresión hacia la ALGH.

A pesar de la diversidad de enfoques quirúrgicos para tratar la inestabilidad anterior de hombro, la literatura no muestra mayores diferencias entre técnicas quirúrgicas y progresión hacia una artropatía, enfatizando la relevancia de abordar factores de riesgo específicos y fundamentalmente la elección del procedimiento según la necesidad de nuestros pacientes.
Evolución de la tenodesis extraarticular lateral: Perspectivas actuales en cirugía primaria de ligamento cruzado anterior
Authors: Calvo Rafael , Isla Jorge , Figueroa David , Edwards Diego , González Waldo
Published: December 2024

Introducción La reconstrucción quirúrgica es el estándar de oro en el tratamiento de rotura de ligamento cruzado anterior (LCA) y tiene como objetivo restablecer la anatomía normal, restaurar la estabilidad de la rodilla, y prevenir el desarrollo tanto de patologías meniscales como las de cartílago. Esta cirugía cuenta con una tasa de fallo por re-rotura del injerto de hasta un 6-10%, razón por la que en la última década se han descrito diversas técnicas asociadas para disminuir dicha tasa de fracaso. La tenodesis extraarticular lateral (TEA) es un procedimiento quirúrgico asociado a la RLCA con el que se ha reportado una disminución de importante en las tasas de fracaso posterior a una reconstrucción primaria de LCA.

Objetivos Describir la tendencia y factores asociados a la utilización de tenodesis extraarticular en cirugía de RLCA durante los últimos 5 años en un centro clínico nacional de alto volumen.

Métodos Estudio de cohorte retrospectivo. Se estudió una base de datos anonimizada consistente de todas las cirugías primarias de LCA realizadas entre el 2018 y el 2023 en nuestra institución. Se incluyeron pacientes mayores de 14 años sometidos a cirugía primaria de LCA, y se excluyeron aquellos sometidos a cirugías de revisión, pacientes con lesiones multiligamentarias, o con fracturas asociadas. Se realizó estadística descriptiva para las variables edad, sexo, tipo de injerto utilizado, y realización de TEA durante la cirugía. Para el análisis de tendencia se utilizó la prueba de Prais-Winsten. Para el análisis de asociación entre sexo, tipo de injerto, año y TEA, se utilizó prueba de Chi2. Se construyó un modelo de regresión logística con la información obtenida.

Resultados Se analizaron 922 pacientes con una media de edad de 30.2 años, 687 de sexo masculino (74.6%). El injerto más utilizado en la muestra fue el de tendones isquiotibiales (75.1%). En el periodo estudiado, se realizó una TEA en un 14.21% de los participantes. Los resultados porcentuales de indicación por año fueron 5%, 8%, 10%, 27%, 17%, 30% en el periodo 2018-2023, respectivamente. La prueba de Prais-Winsten con p < 0.05 mostró un aumento significativo en la utilización de la TEA a lo largo de los años. Se encontró una asociación significativa entre una menor edad y TEA (p < 0.01). No se encontró una asociación significativa entre el sexo y TEA (p = 0.360), ni entre el tipo de injerto y TEA (p = 0.235).

Conclusiones En nuestro medio, existe una tendencia importante al alza de la utilización de TEA en pacientes sometidos a cirugía primaria de RLCA. Los pacientes sometidos a TEA son significativamente más jóvenes, hiperlaxos y practican deportes de contacto.
Hematological Parameters and Systemic Inflammatory Markers in Children with Viral Acute Lower Respiratory Tract Infections
Authors: Sert Sadiye , Sargın Fatma , Say Şerife Karaçal , Erayman Berna , Buldu Ebru
Published: December 2024

Objective Viral acute lower respiratory tract infections (ALRTIs) are a leading cause of morbidity and mortality in children, particularly those under 5 years. Accurate diagnosis and timely management are crucial to improve outcomes. This study aimed to address the lack of comparative analysis between hematological and systemic inflammatory markers concerning established disease severity scores in children with viral ALRTIs. We sought to evaluate the correlations between these markers and severity scores to identify which parameters provide the most reliable predictive value for assessing the severity of ALRTI diagnoses in this population.

Methods This retrospective cross-sectional study included 191 children hospitalized with viral ALRTIs. Hematological parameters and systemic inflammatory markers were analyzed. The pediatric respiratory severity score (PRESS) was used to assess disease severity.

Results Significant differences in some hematological parameters and systemic inflammatory markers across severity groups were observed. Significant correlations were found between PRESS and various hematological parameters, including white blood cell count, lymphocyte count, monocyte count, platelet count, red cell distribution width, plateletocrit, and lymphocyte-to-C-reactive protein ratio. Multivariate analysis identified PRESS, hemoglobin level, and mean platelet volume-to-lymphocyte ratio as independent predictors of pediatric intensive care unit (PICU) admission. Receiver operating characteristic analysis revealed that platelet count had the highest area under the curve for predicting PICU admission.

Conclusion We found that values of hematological parameters and systemic inflammatory markers together with clinical severity scores can be used to assess the severity of ALRTIs in children. The identified cutoff values for these markers can aid in predicting PICU admission risk.
46,XX Disorders of Sex Development: A Case with p.Arg92Trp Variant in NR5A1
Authors: Oktay Mehmet Ali , Akın Agah , Döğer Esra , Kayhan Gülsüm , Kocaman Gizem Eşme , Çamurdan Mahmut Orhun , Bideci Aysun
Published: December 2024

Ovotesticular (OT) disorders of sex development (DSDs) are marked by the simultaneous presence of ovarian and testicular tissues within the gonads. The appearance of external genitalia does not necessarily correlate with gonadal histology. Variants in the NR5A1 gene can result in SRY-negative DSD. In this report, we present a case involving a variant in the NR5A1 gene. A 3-year-old phenotypic male presenting with micropenis, penile hypospadias, and a bifid scrotum was identified to have a c.274C > T, p.Arg92Trp variant in the NR5A1 gene, along with a 46,XX karyotype. Genetic factors such as variants in the NR5A1 gene, independent of SRY, can lead to the development of both testicular and OT DSDs, possibly manifesting in varying gender phenotypes.
Alteration of the equilibrium configuration of a magnetic system during parametric excitation
Authors: Zvyagin A. A. , Tsukernik V. M.
Published: December 2024

We find the equilibrium configuration of a spin system under conditions of low temperature excitation by an alternating magnetic field parallel to the constant one.
Anomalous pressure dependence of the AFMR spectrum of (C2H5NH3)2CuCI4
Authors: Vasyukov V. N. , Lukin S. N. , Telepa V. T.
Published: December 2024

A study has been made of the effect of uniform compression on the frequency-field dependence of AFMR in the rhombic easy-axis antiferromagnet (C2H5NH3)2CuC14. The spin-flop transition field and the activation energy of the low-frequency branch of the spectrum have been found to depend nonmonotonically on the magnitude of the uniform compression.
Influence of high-intensity ultrasound on the band structure of metals
Authors: Grechnev G. E.
Published: December 2024

The band structure of the electron spectrum of a nontransition metal in the presence of a standing ultrasonic wave is calculated within the framework of the pseudopotential method. It is established that superlattice splittings induced in the spectrum near the faces of the Brillouin zone by the onset of an additional long period are governed by electron transitions of the nature of Umklapp processes and greatly exceed the “acoustic” gaps near the bottom of the conduction band. The principal energy gaps on the Bragg planes corresponding to reciprocal lattice vectors G quasicollinear with the sound amplitude u0 decrease considerably with an increase in u0.
Equilibrium and stability of charged and uncharged helium film surfaces
Authors: Zhakin A. I.
Published: December 2024

We have studied the equilibrium shape and stability of charged and uncharged surfaces on thin films of liquid helium. We assume that the average distance between electrodes is much greater than the film thickness. We used a variational method to obtain the necessary and sufficient conditions for the equilibrium and stability of the equilibrium state of a charged surface. The sufficient condition has the form λ. > 0 where λ. is the smallest eigenvalue of the corresponding boundary value problem. We have studied the stability of a horizontal helium film with a charged surface. The film is on a finite thickness dielectric substrate. It is shown that the critical electron density increases as the dielectric constant of the substrate decreases and as its thickness increases. The effect of substrate roughness on the shape of the free film surface is studied in the linear approximation. It is shown that the surface always replicates the substrate shape when no electrons are present. When the surface is charged, situations can arise where depressions appear in the surface above convexities in the substrate, and vice versa.
Interaction of a moving resistive domain with localized inhomogeneities in superconducting films
Authors: Ivanchenko Yu. M. , Medvedev Yu. V. , Yarish A. N.
Published: December 2024

Stable traveling domains with finite resistance [Gurevich and Mints, Pis’ma Zh. Eksp. Teor. Fiz. 31, No. 1, 52 (1980)] (resistive domains (RD)) can exist in homogeneous type-II superconductors in the presence of a transport current. In this paper, the possibility that these domains are stopped by inhomogeneities which they encounter as they move along the film sample is studied theoretically. To this end, an equation determining the velocity x˙0 of a RD (x0 is the position of the center of the domain) relative to the location of the inhomogeneity, characterized by an excess liberation of a small amount of heat at the moment the RD impinges against it, is obtained.
Point-contact spectroscopy of the electron–phonon interaction in polyvalent nontransition metals: indium and thallium
Authors: Kamarchuk G. V. , Khotkevich A. V.
Published: December 2024

The electron–phonon interaction in indium and thallium is investigated experimentally by the point-contact spectroscopy method. The point-contact functions of the electron–phonon interaction are determined from the measured variations of the second derivatives of the point-contact current–voltage characteristics as a function of the voltage. The results are compared with the Éliashberg electron–phonon interaction functions and the densities of phonon states. The variations of the relative intensity and the positions of the maxima of the point-contact spectra of thallium are interpreted as the onset of a possible anisotropy of the electron–phonon interaction in this metal. Two-phonon electron-scattering processes in thallium point contacts are investigated.
Multiphoton absorption in antiferromagnetic manganese compounds
Authors: Lebedenko A. N. , Matyushykin É. V. , Smushkov V. I.
Published: December 2024

We have studied multiphoton absorption in three-dimensional (RbMnCl3, CsMnCl3) and quasi-two-dimensional (NaMnCl3, BaMnF4, and [CH2(NH3)2CH] MnCl4) layered antiferromagnets for temperatures from 2–20.4 K. We observe that the nonlinearity in the absorption process is not the same in the various crystals, and depends on the intensity of the transmitted light in some of them. A relationship between the observed phenomena and the crystal structure is demonstrated.
Magnetooptic determination of the magnetic point group of Ca3Mn2Ge3O12
Authors: Kharchenko N. F. , Eremenko V. V. , Gnatchenko S. L. , Mil’ner A. A. , Sofroneev S. V.
Published: December 2024

On the basis of measurements of the linear birefringence and dichroism due to the linear magnetooptic effect we have determined the magnetic point group for the noncollinear antiferroelectric crystal Ca3Mn2Ge3O12. The group obtained, 4̲/m, differs from the 4/m group obtained previously from neutron diffraction data.
Superconducting transition temperature of cold-deposited indium films
Authors: Semenenko E. E. , Tutov V. I.
Published: December 2024

The temperature dependence of the superconducting transition temperature Tc has been investigated for thin indium films (200–18 Å), obtained by condensing the metal vapor in a vacuum better than 10−10 mm Hg onto a glass substrate cooled down to 2 K. As the thickness is decreased from 200 to 18 Å, Tc increases from 4.20 to 4.65 K. The resistivity at the same time increases from 4 to 180μΩ·cm. The behavior of Tc(d) is explained by the further softening of the phonon spectrum of cold-deposited indium films on reducing their thickness with a simultaneous increase in the electron–phonon coupling constant.
The motion of dislocations in zinc single crystals in the normal and superconducting states
Authors: Gektina I. V. , Kuz’menko I. N. , Lavrent’ev F. F. , Pustovalov V. V. , Shumilin S. É.
Published: December 2024

The motion of dislocations in zinc single crystals in the normal and superconducting states has been measured at 0.5 K. The mobile dislocations were generated in the crystal by scratching its surface. The motion of dislocations in the slip systems (0001)〈112¯0〉 or {1122¯}〈112¯3〉 and also in the twins {11¯02}〈11¯01〉 was observed, depending on the orientation of the surface studied. An influence was found of the state of the superconductor on the path lengths of the basal and pyramidal dislocations, and also on elastic twinning.
Nonlinear electronic heat capacity of A-15 compounds
Authors: Noskova L. M. , Rozenfel’d E. V. , Irkhin Yu. P.
Published: December 2024

The electronic heat capacity (CE) of a metal with a strongly energy-dependent electronic density of states is studied. It is shown that in this case substantial nonlinear contributions to the temperature dependence of Ce(T) appear. The electronic and phonon (Cp) heat capacities of Nb3Sn and V3Si are specifically calculated and compared with experiment. The proposed procedure can also be used for other transition metals and compounds with a complicated energy structure.
Electrodynamic properties of metals in the current state
Authors: Makarov N. M. , Yampol’skii V. A.
Published: December 2024

An asymptotically exact theory of current states in metals under conditions of the anomalous skin effect is constructed. Cases of both weak and strong nonlinearity are investigated. The distribution of the electromagnetic field in the sample is studied. It is shown that in the state of strong nonlinearity rapid changes in the conductivity, occurring during each period of the wave, cause a jump-like change in the thickness of the skin layer as a function of time. The jumps in the skin layer cause rapid changes in. the amplitude of the electric field at the surface of the sample, which makes it possible to observe this unusual behavior of the skin layer experimentally.
Rearrangement of the magnetic excitation spectrum of weakly doped CoCO3 in an external field
Authors: Naumenko V. M. , Pishko V. V.
Published: December 2024

In crystals of CoCO3 containing a low concentration of the impurities FeCO3, MnCO3, and NiCO3, we have studied the collective rearrangement of the spectrum of the intrinsic and impurity magnetic excitations which takes place as their frequencies approach each other in an external magnetic field. Measurements were performed in the frequency region 1−28 cm−1 in pulsed fields of strengths up to 16 T. The observed anomalies in the spectrum of a weakly doped crystal are explained as a delocalization of the impurity excitations as an indirect interaction arises among them via the excitations of the host crystal matrix. It is shown that the impurity FeCO3 in CoCO3 is an impurity of an orthogonal type, the impurity MnCO3 is of a collinear type, ferromagnetically coupled with the matrix, and NiCO3 is of a collinear type, antiferromagnetically coupled to the CoCO3 matrix.
Design and commissioning of the PRIOR-II “proton microscope for FAIR”
Authors: Schanz M. , Varentsov D. , Allison J. C. , Bagnoud V. , Belikov R. , Blazevic A. , Eisenbarth U. , Freeman M. S. , Gavrilin R. , Jacoby J. , Kalimov A. G. , Khurchiev A. , Mariam F. G. , Merrill F. E. , Müller-Münster A. , Neukirch L. P. , Neff S. , Nikolaev D. , Schmidt J. L. , Skobliakov A. , Weyrich K. , Winkler B. , Zielbauer B.
Published: December 2024

A new high energy proton radiography facility PRIOR-II (Proton Microscope for FAIR) has been designed, constructed, and successfully commissioned at the GSI Helmholtzzentrum für Schwerionenforschung (Darmstadt, Germany) pushing the technical boundaries of charged particle radiography with normal conducting magnets to the limits. The setup is foreseen to become a new and powerful user facility for carrying out fundamental science experiments in the fields of plasma and shock wave physics, material science, and medical physics. It will help address several unsolved scientific challenges, which require high-speed and precise non-invasive diagnostic methods capable of probing matter with up to 100 g/cm2 areal density. PRIOR-II is specifically designed to utilize the full timing capabilities of the SIS-18 synchrotron at GSI for ultra-fast dynamic experiments with up to 4 GeV protons and will also be fielded at the future FAIR facility, where higher proton energies and beam intensities will be available. This will enable experiment geometries with even higher areal densities, more flexible experiment timing, and further enhanced spatial resolution.
Decoupling effect and socioeconomic drivers of energy consumption: A case study of the top five urban agglomerations in China
Authors: Zhang Yu , Li Mengxue , Mao Yanying , Jiao Liudan , Zhao Congxiao
Published: December 2024

The sustainability of energy consumption in urban agglomerations has become a growing concern. This study investigates the decoupling effect and socioeconomic factors of energy consumption in the top five urban agglomerations in China from 2011 to 2020. First, the decoupling relationship between energy consumption and economic development was assessed. Subsequently, the logarithmic mean Divisia index method was used to decompose the change of energy consumption into five factors. The main findings show the following: (1) The decoupling status of the five major urban agglomerations was unstable during the whole period, and expansive negative decoupling was prominent in five urban agglomerations. (2) The main factors that contributed to the energy consumption growth were investment effect (ΔCI), energy intensity effect (ΔCEI), per urban population gross domestic product effect (ΔCPG), and urbanization rate effect  (ΔCUR), while the only factor that hindered energy consumption growth was investment population support coefficient effect (ΔCIP). Finally, the policy recommendations aim to help the Chinese policymakers and practitioners achieve a win–win balance between energy-saving and economic growth in the Chinese context, such as promoting low-carbon, economic, and green urban investment construction modes, reducing energy intensity, and promoting urbanization in an orderly manner.
Generalized Langevin equation for a tagged monomer in a Gaussian semiflexible polymer
Authors: Durang Xavier , Lim Chan , Jeon Jae-Hyung
Published: December 2024

In this study, we present a comprehensive analysis of the motion of a tagged monomer within a Gaussian semiflexible polymer model. We carefully derived the generalized Langevin equation (GLE) that governs the motion of a tagged central monomer. This derivation involves integrating out all the other degrees of freedom within the polymer chain, thereby yielding an effective description of the viscoelastic motion of the tagged monomer. A critical component of our analysis is the memory kernel that appears in the GLE. By examining this kernel, we characterized the impact of bending rigidity on the non-Markovian diffusion dynamics of the tagged monomer. Furthermore, we calculated the mean-squared displacement of the tagged monomer using the derived GLE. Our theoretical findings were corroborated by the Langevin dynamics simulation and scaling theory. Our results not only show remarkable agreement with previously known results in certain limiting cases but also provide dynamic features over the entire timescale.
A configurable two-tone electron spin resonance spectrometer
Authors: Collett Charles A. , Davvetas Sofia M. , Alsuhaymi Abdulelah , Timco Grigore A.
Published: December 2024

Electron spin resonance (ESR) is a powerful tool for characterizing and manipulating spin systems, but commercial ESR spectrometers can be inflexible and designed to work in narrow frequency bands. This work presents a spectrometer built from off-the-shelf parts that, when coupled with easy-to-design resonators, enables ESR over a broad frequency range, including at frequencies outside the standard bands. It can operate at either a single frequency or at two frequencies simultaneously. The spectrometer is controlled by a field programmable gate array (FPGA), and new capabilities can be easily added by reconfiguring the FPGA and adding or swapping components. We demonstrate the capabilities of the spectrometer using the molecular nanomagnet Cr7Mn, including simultaneous ESR at frequencies separated by nearly 500 MHz.
Design, development, and electrical characterization of a parabolic dish photovoltaic thermal concentration system
Authors: Fuentes-Morales Rosa F. , Díaz-Ponce Arturo , Acosta-Pérez Edgar D. , Martell-Chavez Fernando , Peña-Cruz Manuel I. , Rodrigo Pedro M.
Published: December 2024

Hybrid solar concentrating systems are recognized for their superior efficiency in generating both electricity and heat from solar radiation compared to standalone thermal or photovoltaic systems. However, these systems require greater technological maturity, are complex to produce, and are currently expensive, which restricts their commercial deployment. Few reported prototypes exist, and they offer significant opportunities for improvement. This article presents a prototype of a photovoltaic thermal concentrator that uses a parabolic dish, state-of-the-art multi-junction solar cells equipped with secondary optics, and an easy-to-build active cooling system with straight fins as channels to circulate water. It covers the design, optical simulation, construction, and electrical characterization of the prototype. One advantage of the prototype is its more straightforward structure compared to other reported prototypes, which facilitates manufacturing. The prototype was tested outdoors with and without active cooling. In the first case, it was observed that without the cooling system, the concentrating photovoltaic receiver temperature exceeded 108 °C, causing the electrical efficiency to drop to 8.31%. In the second case, the receiver temperature was maintained below 50 °C. Under clear-sky conditions, the system achieved an average real concentration of 414.8 suns and an average electrical efficiency of 29.75%, representing one of the highest efficiencies reported for these hybrid systems. This experimental study marks a fundamental step toward advancing photovoltaic thermal concentrator systems and bringing them closer to technological maturity. This study demonstrates a scalable solution for hybrid solar concentration, showcasing significant advancements in thermal management and system efficiency.
Fast determination of terahertz polarization azimuth angle based on the core-anti-resonant effect
Authors: Mei Yangjun , Tian Yifu , Han Yongpeng , Lao Li , Zhao Jiayu
Published: December 2024

The azimuth angle of linearly polarized light plays a crucial role in optical mechanism investigations and various applications. However, in the terahertz (THz) band, traditional detection methods suffer from low efficiency or require complex apparatus. In this work, based on the core-anti-resonant reflection (CARR) principle, we propose a polarization-sensitive CARR cavity, namely, a simple 3D-printed tube with an Archimedean spiral structure of the cross section, which links the input linear polarization azimuth angle to the output resonant frequencies. In this way, the spatial polarization angle can be rapidly resolved via the Fourier-transformed THz spectrum from the detected single THz temporal pulse. Therefore, the experimental system configuration is simplified, and more importantly, the detection efficiency has been significantly enhanced.
Commissioning and first result of undulator based atomic, molecular, and optical sciences (AMOS) beamline at Indus-2 synchrotron radiation source
Authors: Singh Param Jeet , Maitra Tamaghna , Das A. K. , Yadav A. K. , Kumar Ravi , Agarwal Ankur , Dvivedi Ashutosh , Gorai K. K. , Shastri A. , Bhattacharyya D. , Udupa D. V.
Published: December 2024

We present a comprehensive overview of the commissioning process and initial results of a synchrotron beamline dedicated to atomic, molecular, and optical sciences at the BL-5 undulator port of the Indus-2 synchrotron facility, Raja Ramanna Center for Advanced Technology, Indore, India. The beamline delivers a photon flux of ∼1012 photons/s with high resolving power (∼10 000) over an energy range of 6–800 eV, making it suitable for high-resolution spectroscopy in atomic, molecular, and optical science. The energy tunability from vacuum ultraviolet to soft x-ray (6–800 eV) is achieved through a varied line spacing plane grating monochromator with four gratings: very low energy (VLEG), low energy (LEG), medium energy (MEG), and high energy (HEG). These gratings cover ranges of 6–18, 15–45, 42–126, and 90–800 eV, respectively. A differential pumping system allows windowless transmission of VUV and soft x-ray photons for gas-phase spectroscopic experiments. The beamline also includes an x-ray absorption spectroscopy (XAS) station for solid samples. To demonstrate efficiency, a spectrum was recorded using all four gratings in the 6–300 eV energy range. Standard spectra of Xe and O2 verified the resolution, achieving a resolving power of 7740 with the VLEG, consistent with design specifications. XAS spectra of Cu M, C, and O K-edges were also obtained using MEG and HEG. Details on vacuum level, grating operation, and the first commissioning experiments are presented.
Improving academic–industry collaboration: A case study of UK distribution system operators
Authors: Bright Jamie M. , Ozdemir Hilal , Donaldson Daniel L. , Robertson Rosabella F.
Published: December 2024

As power networks around the world undergo profound transformation driven by the decarbonization of electricity, the integration of renewable energy resources and low carbon technologies, and more active network participation at the grid edge, distribution network operators have encountered and continue to face various challenges. Both industry and academia are actively involved in addressing these challenges, with a common focus on ensuring the operational efficiency and reliability of the electricity network. This Perspective article analyzes the academia–industry relationship in the energy sector with a first-hand experience set of insights from the newly established Distribution System Operators in the United Kingdom. This perspective identifies and explores barriers to academia–industry collaboration in the forms of willingness, communication, objectivity, understanding, resources, and outcomes. We offer practical recommendations to both parties, supported by real resources and actionable strategies to overcome these challenges.
Characterizing nonlinear piezoelectric dynamics through deep neural operator learning
Authors: Chandra Abhishek , Kapoor Taniya , Curti Mitrofan , Tiels Koen , Lomonova Elena A.
Published: December 2024

Nonlinear hysteresis modeling is essential for estimating, controlling, and characterizing the behavior of piezoelectric material-based devices. However, current deep-learning approaches face challenges in generalizing effectively to previously unseen voltage profiles. This Letter tackles the limitation of generalization by introducing the notion of neural operators for modeling the nonlinear constitutive laws governing inverse piezoelectric hysteresis, specifically focusing on the relationship between voltage inputs and displacement responses. The study utilizes two neural operators—Fourier neural operator and the deep operator network—to predict material responses to unseen voltage profiles that are not part of the training data. Numerical experiments, including butterfly-shaped hysteresis curves, show that in accuracy and generalization to unseen voltage profiles, neural operators outperform traditional recurrent neural network-based models, including conventional gated networks. The findings highlight the potential of neural operators for modeling hysteresis in piezoelectric materials, offering advantages over existing methods in varying voltage scenarios.
Measuring the sensitivity of imaging plates to keV carbon ions
Authors: Hayashi Yukio , Mori Michiaki , Kotaki Hideyuki , Onoda Shinobu , Yamada Keisuke , Kando Masaki
Published: December 2024

Imaging plates (IPs) are valuable tools for measuring the intensity of ionizing radiation such as x-rays, electrons, and ions. In this work, we measured the sensitivity of IPs to carbon ions in the unexplored energy region of 0.7–10 keV. These carbon ions were generated using a low-energy electron cyclotron resonance ion-beam source and were subsequently transported to the IPs via an energy-selecting bending magnet. We found that the measured sensitivity exhibited a nonlinear relationship with ion energy, for which the existing formula does not account. Thus, we propose a new formula that can effectively describe the sensitivity of IPs to carbon ions with energies from the single-keV range to higher values.
Miniature InGaN-based LEDs operating at a wavelength of 672 nm with an external quantum efficiency of 9.1% fabricated on a GaN template layer
Authors: Xing Kun , Jin Zhengxian , Zeng Hong , Pan Zhengwei , Wang Haifeng , Jiang Xiaolong , Chen Qiang
Published: December 2024

Modern application trends for the development of RGB displays with a high color rendering index (CRI) require light-emitting diode (LED) display technology with greater miniaturization and efficient LEDs operating at deep red wavelengths greater than 650 nm. Although InGaN-based LEDs have achieved high miniaturization performance, efforts to obtain deep-red emission by increasing the indium content introduce a number of factors limiting optical performance, such as high in-plane stress, high dislocation densities, and phase separation. The present work addresses this issue by fabricating deep-red emitting InGaN-based LEDs on an underlying GaN template layer grown from hexagonal GaN column structures formed on a porous SiNx masking layer and coalesced in situ as an underlying layer with significantly reduced internal stresses and dislocation densities. As a result, the fabricated miniature LEDs obtain an external quantum efficiency of 9.1% and a peak wavelength of 672 nm at a current density of 0.4 A/cm2. Accordingly, this work confirms the potential for fabricating InGaN-based LEDs to achieve high-CRI mini/micro RGB displays.
Two-phase fluid resonance frequency and improved elastic water model for pipes conveying fluid with entrapped air
Authors: Li Haoran , Bai Changqing
Published: December 2024

The entrapped air in pipe has a significant impact on the dynamic characteristics of the pipeline system, as it can induce transient high pressures and pressure oscillations similar to water hammer during system opening and closing. In this study, plane wave equations for the liquid and air phases in pipe are formulated with considering various conditions of entrapped air. The approximate solution for the resonance frequency of the two-phase fluid is derived via the separation variables method and the coupling relationship at the air–liquid interface. The resonance frequencies obtained from the approximate solution closely match those from the finite element method, confirming the accuracy and universality of the presented approximate solutions. Furthermore, based on the criterion of consistent first-order resonance frequency, an improved elastic water model and the corresponding analysis process of fluid dynamic response are proposed by correcting the first resonance frequency of the dynamic model of pipes conveying fluid with entrapped air. The predicted results are consistent with experimental data and computational fluid dynamics results, thus validating the proposed model. Compared with existing models, the improved elastic water model proposed in this paper can obtain accurate calculation results under all entrapped air conditions, overcoming the limitation of existing models that are only applicable to a single entrapped air condition. It is found that the air–liquid interface angle influences the fluid resonance frequency and dynamic response significantly. As the angle of the air–liquid interface increases, the pressure peak and oscillation frequency of the pipe fluid response decrease remarkedly.
A fins-shaped bidirectional linear ultrasonic motor driven by a single-phase signal
Authors: He Jie , Fan Pingqing , Ma Xipei , Wang Yansong
Published: December 2024

Inspired by the propulsion mechanism of fish swimming through tail-fin oscillations, we have developed and experimentally studied a high-performance miniature bending vibration linear ultrasonic motor driven by a single-phase standing wave. A symmetrical structural design achieves bidirectional motion with consistent output characteristics. Two lead zirconate titanate (PZT) piezoelectric patches are symmetrically distributed on a metal elastic body’s upper and lower sides. In the stator, a sinusoidal signal is applied only to the piezoelectric patch on one side, while the patch on the opposite side is either left open or short-circuited to the ground. This results in an asymmetry in the structural damping between the upper and lower sides of the stator. The first-order bending vibration of the stator generates displacement in an inclined direction at the end of the driving foot. The motor achieves forward and backward motion by applying the same voltage to the piezoelectric patches on different sides. The dimensions of the stator have been finalized, and a prototype of the designed motor has been fabricated. Subsequent experimental tests were conducted to evaluate the prototype’s performance, including its mechanical output characteristics. At a frequency of 138.3 kHz, the maximum speed of the motor without load is 134.58 mm s−1. Under a voltage of 200 Vp-p and a preload of 3 N, the motor’s maximum output thrust is approximately 0.3 N. The actual mass of the motor is approximately 1.2 g, resulting in a thrust-to-weight ratio of 25.
Off-equatorial deflections and gravitational lensing in Kerr spacetime and the effect of spin*
Authors: Jiang 姜 Tingyuan 霆远 , Xu 许 Xiaoge 笑歌 , Jia 贾 Junji 俊基
Published: December 2024

This paper investigates off-equatorial plane deflections and gravitational lensing of both null signals and massive particles in Kerr spacetime in the weak deflection limit, considering the finite distance effect of the source and detector. This is the effect caused by both the source and detector being located at finite distances from the lens although many researchers often use the deflection angle for infinite distances from sources and detectors. The deflection in both the

and

directions is computed as a power series of

and

, where

are the spacetime mass and source and detector radii, respectively, and

is the minimal radial coordinate of the trajectory. The coefficients of these series are simple trigonometric functions of

, the extreme value of the

coordinate of the trajectory. A set of exact gravitational lensing equations is used to solve for

and

for given deviation angles

and

of the source, and two lensed images are always obtained. The apparent angles and their magnifications of these images and the time delays between them are solved. Additionally, their dependences on various parameters, particularly spacetime spin

, are analyzed in depth. We find that generally two critical spacetime spin values exist that separate the case of test particles reaching the detector from different sides of the

axis from the cases in which the images appear from the same side in the celestial plane. Three potential applications of these results are discussed.
Holographic Einstein rings of AdS black holes in Horndeski theory*
Authors: Luo 罗 Zhi 智 , He 何 Ke-Jian 柯腱 , Li 李 Jin 瑾
Published: December 2024

Using the AdS/CFT correspondence and wave optics techniques, we conduct an extensive study of the imaging properties of holographic Einstein rings in the context of anti-de Sitter (AdS) black holes (BHs) in Horndeski theory. Our results indicate that the optical characteristics of these holographic Einstein rings are significantly influenced by the observer's position, physical parameters of the BH, nature of the wave source, and configuration of the optical system. Specifically, when the observer is positioned at the north pole of the AdS boundary, the holographic image prominently displays a ring structure aligning with the BH's photon sphere. We thoroughly analyze the effect of various physical parameters — including the observation position, event horizon radius, temperature, and the parameter γ in Horndeski theory — on the holographic Einstein rings. These parameters play a crucial role in determining the rings' radius and brightness, with variations potentially causing the ring structures to deform or even transform into bright spots. Furthermore, our comparative analysis between wave and geometric optics reveals a strong agreement in predicting the positions and brightness of both the photon and Einstein rings. This paper offers new insights into the spacetime geometry of BHs in Horndeski theory and proposes a promising framework for exploring the gravitational duals of strongly coupled systems.
Geometric Constraints via Page Curves: Insights from Island Rule and Quantum Focusing Conjecture
Authors: Yu Ming-Hui , Ge Xian-Hui
Published: December 2024

Exploring the inverse problem tied to the Page curve phenomenon and island paradigm, we investigate the geometric conditions underpinning black hole evaporation where information is preserved and islands manifest, giving rise to the characteristic Page curve. Focusing on a broad class of static spherical symmetry black hole metrics in asymptotically Minkowski or (anti-)de Sitter spacetimes, we derive a pivotal constraint: the second derivative of blacken factor $f^{\prime \prime}(r_h)<\frac{6 \kappa A^{\prime}(r_h)}{cG_N}$ for which the island exists and reproduce the Page curve. On the other hand, starting from the quantum focusing conjecture theory, we obtain another constraint on the blacken factor: $f^{\prime \prime}(r_h)< \frac{6 \kappa^2 r_h A^{\prime}(r_h) e^{2\kappa r_{\star}(b)} }{cG_N f(b)}$ that the theory can be satisfied. In particular, by studying these two constraints, we find that a common properties. Specifically, we reveal that a universally criterion -- manifested in the negativity of the second derivative of $f(r)$, i.e. $f^{\prime \prime} (r)<0$, in proximity to the event horizon where $r \sim r_h+ {\cal O} (G_N)$, ensures the emergence of Page curves and follows the quantum focusing conjecture in a manner transcending specific theoretical models. Finally, we argue that the negativity of the second derivative of the blacken factor $f(r)$ near the event horizon strongly indicates negative heat capacity, which implies that black holes with a negative heat capacities must have islands and satisfy the quantum focusing conjecture.Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.
Time-dependent prognostic accuracy measures for recurrent event data
Authors: Dey R , Schaubel D E , Hanley J A , Saha-Chaudhuri P
Published: December 2024

In many clinical contexts, the event of interest could occur multiple times for the same patient. Considerable advancement has been made on developing recurrent event models based on or that use biomarker information. However, less attention has been given to evaluating the prognostic accuracy of a biomarker or a composite score obtained from a fitted recurrent event-rate model. In this manuscript, we propose novel measures to characterize the prognostic accuracy of a marker measured at baseline in the presence of recurrent events. The proposed estimators are based on a semiparametric frailty model that accounts for the informativeness of a marker and unobserved heterogeneity among patients with respect to the rate of event occurrence. We investigate the asymptotic properties of the proposed accuracy estimators and demonstrate these estimators’ finite sample performance through simulation studies. The proposed estimators have minimal bias and appropriate coverage. The estimators are applied to evaluate the performance of a baseline forced expiratory volume, a measure of lung capacity, for repeated episodes of pulmonary exacerbations in patients with cystic fibrosis.
Community science brings together natural history collections and historical survey data to understand changing ecological patterns
Authors: Alofs Karen M , King Katelyn B S , Lenard Michael , Schell Justin , Singer Randal A , Wehrly Kevin E , López-Fernández Hernán , Thomer Andrea K
Published: December 2024

Museum specimens document the impacts of interacting and increasingly pervasive environmental stressors on global biodiversity. Environmental, sampling, and management records are needed to interpret the causes of these changes and address collection biases; however, such data are rarely available in museum catalogues. We outline a process to join collections and associated data using data science workflows in tandem with community science tools. Our approach is illustrated with a case study of lake survey data from Michigan that provide ecological context for catalogued fish specimens. Using the web-based community science platform Zooniverse, we engage stakeholders, public, and educational audiences. Our process includes five key steps: archive assessment and preparing images, workflow development, community engagement and data transcription, data curation, and data archiving. Integrating historical records with museum specimens can clarify environmental impacts on biodiversity over recent history and refine our predictions of future impacts.
Photoredox catalysis using methoxyarenes: mechanistic studies and synthetic applications
Authors: Tayu Masanori , Matsukuma Kakeru , Yamaguchi Tomohisa , Noji Masahiro , Hayashi Satoshi , Ohrui Sayaka , Saito Nozomi
Published: December 2024

Bismethoxybinaphthyl was demonstrated to be an effective photoredox catalyst. This study explored the utility of bismethoxybinaphthyl catalysts in various photoredox reactions, including trifluoromethylation, C–H imidation, intramolecular lactonization, benzylation, and reductive coupling via the 1-electron reduction of carbonyl groups. Electrochemical analyses were conducted to determine the redox potential of the bismethoxybinaphthyl catalyst, revealing its notably stronger reducing power compared with representative organic photoredox catalysts. Furthermore, spectroscopic studies were performed to elucidate the mechanism of photoinduced electron transfer. It was found that bismethoxybinaphthyl does not form an electron donor–acceptor complex; instead, it facilitates electron transfer through a locally excited state.