bluuebunny/crossref_metadata_2025 huggingface dataset:
Glitches in solar-like oscillating F-type stars
Authors: Deal M. , Goupil M.-J. , Cunha M. S. , Monteiro M. J. P. F. G. , Lebreton Y. , Christophe S. , Pereira F. , Samadi R. , Oreshina A. V. , Buldgen G.
Published: March 2023

Context. The transition between convective and radiative stellar regions is still not fully understood. This currently leads to a poor modelling of the transport of energy and chemical elements in the vicinity of these regions. The sharp variations in sound speed located in these transition regions give rise to a signature in specific seismic indicators, opening the possibility to constrain the physics of convection to radiation transition. Among those seismic indicators, the ratios of the small to large frequency separation for l = 0 and 1 modes (r010) were shown to be particularly efficient to probe these transition regions. Interestingly, in the Kepler Legacy F-type stars, the oscillatory signatures left in the r010 ratios by the sharp sound-speed variation have unexpected large amplitudes that still need to be explained.

Aims. We analyse the r010 ratios of stellar models of solar-like oscillating F-type stars in order to investigate the origin of the observed large amplitude signatures of the r010 ratios.

Methods. We tested different possibilities that may be at the origin of the large amplitude signatures using internal structures of stellar models. We then derived an analytical expression of the signature, in particular, of the amplitude of variation, that we tested against stellar models.

Results. We show that the signature of the bottom of the convective envelope is amplified in the ratios r010 by the frequency dependence of the amplitude compared to the signal seen in the frequencies themselves or the second differences. We also find that with precise enough data, a smoother transition between the adiabatic and radiative temperature gradients could be distinguished from a fully adiabatic region. Furthermore, we find that among the different options of physical input investigated here, large amplitude signatures can only be obtained when convective penetration of the surface convective zone into the underlying radiative region is taken into account. In this case and even for amplitudes as large as those observed in F-type stars, the oscillating signature in the r01 ratios can only be detected when the convective envelope is deep enough (i.e. at the end of the main sequence). Assuming that the origin of the large amplitude glitch signal is due to penetrative convection (PC), we find that the PC must extend downward the convective to radiative transition significantly (about 1 − 2Hp) in order to reproduce the large amplitudes observed for the ratios of F-type stars. This deep extension of the convective envelope causes doubt that the origin of the large amplitudes is due to PC as it is modelled here or implies that current stellar modelling (without PC) leads to an underestimation of the size of convective envelopes. In any case, studying the glitch signatures of a large number of oscillating F-type stars opens the possibility to constrain the physics of the stellar interior in these regions.
SRG/eROSITA and XMM-Newton observations of Vela Jr
Authors: Camilloni Francesco , Becker Werner , Predehl Peter , Dennerl Konrad , Freyberg Michael , Mayer Martin G. F. , Sasaki Manami
Published: March 2023

Context. The Vela supernova remnant (SNR) complex is a region containing at least three SNRs: Vela, Puppis A, and Vela Jr. With the launch of the spectro-imaging X-ray telescope eROSITA on board the Spectrum-Röntgen-Gamma (SRG) mission, it became possible to observe the one degree wide Vela Jr in its entirety. Although several previous pointed Chandra and XMM-Newton observations are available, it is only the second time after the ROSAT all-sky survey that the whole remnant was observed in X-rays with homogeneous sensitivity.

Aims. Vela Jr is one of the few remnants emitting in the TeV band, making it an important object in shock acceleration studies. However, the age and distance determination using X-ray emission is largely hampered by the presence of the Vela SNR along the same line. With the eROSITA data set our aim is to characterize the emission of Vela Jr and distinguish it from Vela emission, and also to characterize the spectral emission of the inner remnant.

Methods. We processed the eROSITA data dividing the whole remnant into seven different regions. In addition, images of the whole remnant were employed to pinpoint the position of the geometric center and constrain the proper motion of the CCO. We also employed archival XMM-Newton pointed observations of the NW rim to determine the cutoff energy of the electrons and the expansion velocity.

Results. We find the magnetic field can vary between 2 µG and 16 µG in the NW rim. We also find that the remnant spectrum is uniformly featureless in most regions, except for two inner regions where an extra thermal model component improves the fit. We obtain new coordinates for the geometric remnant center, resulting in a separation of only 35.2 ± 15.8″ from the position of the CCO. As a result, we reinforce the association between the CCO and a proposed faint optical–IR counterpart.
Weakly interacting massive particle cross section limits from LOFAR observations of dwarf spheroidal galaxies
Authors: Gajović L. , Welzmüller F. , Heesen V. , de Gasperin F. , Vollmann M. , Brüggen M. , Basu A. , Beck R. , Schwarz D. J. , Bomans D. J. , Drabent A.
Published: March 2023

Context.Weakly interacting massive particles (WIMPs) can self-annihilate, thus providing us with a way to indirectly detect dark matter (DM). Dwarf spheroidal (dSph) galaxies are excellent places to search for annihilation signals because they are rich in DM and background emission is low. If O(0.1–10 μG) magnetic fields in dSph galaxies exist, the particles produced in DM annihilation emit synchrotron radiation in the radio band.

Aims.We used the non-detection of 150 MHz radio continuum emission from dSph galaxies with the LOw Frequency ARray (LOFAR) to derive constraints on the annihilation cross section of WIMPs in electron–positron pairs. Our main underlying assumption is that the transport of the cosmic rays can be described by the diffusion approximation, which necessitates the existence of magnetic fields.

Methods.We used observations of six dSph galaxies in the LOFAR Two-metre Sky Survey (LoTSS). The data were reimaged, and a radial profile was generated for each galaxy. We also used stacking to increase the sensitivity. In order to derive upper limits on the WIMP cross section, we injected fake Gaussian sources into the data, which were then detected with 2σsignificance in the radial profile. These sources represent the lowest emission we would have been able to detect.

Results.We present limits from the observations of individual galaxies as well as from stacking. We explored the uncertainty due to the choice of diffusion and magnetic field parameters by constructing three different model scenarios: optimistic (OPT), intermediate (INT), and pessimistic (PES). Assuming monochromatic annihilation into electron–positron pairs, the limits from the INT scenario exclude thermal WIMPs (⟨σv⟩≈2.2 × 10−26 cm3 s−1) below 20 GeV, and the limits from the OPT scenario even exclude thermal WIMPs below 70 GeV. The INT limits can compete with limits set byFermi-LAT usingγ-ray observations of multiple dwarf galaxies, and they are especially strong for low WIMP masses.
Optical and near-infrared spectroscopy of the black hole transient 4U 1543–47 during its 2021 ultra-luminous state
Authors: Sánchez-Sierras J. , Muñoz-Darias T. , Casares J. , Panizo-Espinar G. , Armas Padilla M. , Corral-Santana J. , Cúneo V. A. , Mata Sánchez D. , Motta S. E. , Ponti G. , Steeghs D. , Torres M. A. P. , Vincentelli F.
Published: March 2023

We present simultaneous optical and near-infrared spectra obtained during the 2021 outburst of the black hole transient 4U 1543–47. The X-ray hardness-intensity diagram and the comparison with similar systems reveal a luminous outburst, probably reaching the Eddington luminosity, as well as a long-lasting excursion to the so-called ultra-luminous state. VLT/X-shooter spectra were taken in two epochs 14 days apart during the early and brightest part of the outburst, while the source was in this ultra-luminous accretion state. The data show strong H and He I emission lines, as well as high-excitation He II and O III transitions. Most lines are single-peaked in both spectra, except for the O III lines that exhibit evident double-peaked profiles during the second epoch. The Balmer lines are embedded in broad absorption wings that we believe are mainly produced by the contribution of the A2V donor to the optical flux, which we estimate to be in the range of 11–14% in the r band during our observations. Although no conspicuous outflow features are found, we observe some wind-related line profiles, particularly in the near-infrared. Such lines include broad emission line wings and skewed red profiles, suggesting the presence of a cold (i.e., low ionisation) outflow with similar observational properties to those found in other low-inclination black hole transients.
Natural hydrogen potential and basaltic alteration in the Asal–Ghoubbet rift, Republic of Djibouti
Authors: Pasquet Gabriel , Idriss Amin Mohamed , Ronjon-Magand Lou , Ranchou-Peyruse Magali , Guignard Marion , Duttine Mathieu , Ranchou-Peyruse Anthony , Moretti Isabelle
Published: March 2023

The Asal–Ghoubbet active rift in the Republic of Djibouti is a site of interest for geothermal energy and natural hydrogen, and previous studies have indicated that dihydrogen (H2) emanates from this rift. However, the well-known serpentinization reaction does not appear to be the main mechanism generating H2 at this site. Rather, the H2 is generated as follows: (1) by alteration of basaltic lava at depth via reaction with seawater flowing from Ghoubbet Bay towards Lake Asal; (2) by simple degassing of the volcanic chamber located a few kilometers below the Fiale Caldera in the rift axis; or (3) as a result of pyritization processes via the oxidation of H2S. Study of microorganisms did not indicate any production or consumption of H2, CO2, or CH4; therefore, it is unlikely that microorganisms affected H2 gas contents measured at the surface. However, air contamination at fumaroles is typically considerable and may limit interpretation of such processes. Drill cuttings from the Fiale 1 (F1) and Gale le Goma 1 (Glc1) wells (located on the inner and outer rift margins, respectively) were analyzed to determine where H2 is generated. Total rock analyses indicated distinct zones at depths of 464 m and 280 m for F1 and Glc1, respectively, representing the boundary between the Asal and Stratoïd Basalts. 57Fe Mössbauer analyses show a decrease in the percentage of Fe3+ at depth, indicating that Fe2+-rich minerals, particularly in the Stratoïd Basalts, may be a source of H2. Based on well data from the rift center and the outer rift margin, it is evident that H2 is present at the surface in the rift axis and that this area offers good remnant potential because of the presence of Fe-rich chlorite. Conversely, few H2 emissions were measured at the surface on the outer rift margins, although well data showed some H2 (∼0.25%) at depth. The presence of a cap rock in the rift axis has not yet been proven; however, the high loss on ignition and the mineralogy in well Glc1 may indicate that the rocks are sufficiently altered into clays to offer potential as a H2 seal. If so, the rift margins would offer greater exploration potential than the rift center.
Small-time global null controllability of generalized Burgers’ equations
Authors: Robin Rémi
Published: March 2023

In this paper, we study the small-time global null controllability of the generalized Burgers’ equations yt + γ|y|γ-1 yx — yxx = u(t) on the segment [0, 1]. The scalar control u(t) is uniform in space and plays a role similar to the pressure in higher dimension. We set a right Dirichlet boundary condition y(t, 1) = 0, and allow a left boundary control y(t, 0) = v(t). Under the assumption γ > 3/2 we prove that the system is small-time globally null controllable. Our proof relies on the return method and a careful analysis of the shape and dissipation of a boundary layer.
Response of rhizosphere microenvironment to coupling of climate warming and soil pollution
Authors: Lei Na , Zhang Weihua
Published: March 2023

With the development of industrialization, the pollution of heavy metals in soil, such as lead (Pb) and cadmium (Cd), has become increasingly serious. On the other hand, the century old climate warming is considered to be the result of the significant increase in the concentration of greenhouse gases, such as CO2, in the atmosphere. These changes will affect the function and stability of the terrestrial ecosystem. Therefore, in recent years, there are more and more studies on the effects of heavy metal pollution and elevated atmospheric CO2 concentration on plants. But most of them focus on the study of the aboveground part of herbaceous plants under the action of single factor, and the study of the soil microenvironment of woody plants under the combined action of these environmental factors is relatively less. This study summarized the response of rhizosphere microenvironment to the coupling of climate warming and soil pollution, in order to provide theoretical reference for improving soil quality and ecological environment.
Numerical investigation of poroelastic effects during hydraulic fracturing using XFEM combined with cohesive zone model
Authors: Ren Xiaoyu , Guan Yueyang , Zhang Xiaofei , Liu Xiaobao , Liu Jie , Liu Kang , Luo Jiangwei , Shi Guiyuan
Published: March 2023

Hydraulic fracturing is an effective technology used to stimulate hydrocarbon production from unconventional reservoirs. Numerical simulation of the hydraulic fracturing process plays a key role in the design of hydraulic fracturing. However, most of existing models are overly simplified by neglecting the poroelasticity of rock matrix, which may have a substantial effect on the growth of hydraulic fractures, especially in oil and/or water saturated formations. In this study, we developed a fully coupled finite element model for hydraulic fracture propagation in permeable formations by combining XFEM technique with cohesive zone model, and used it to investigate the effects of poroelasticity on the geometry evolution of single fracture which initiated from an injection point. Fluid flow within the fractures, Darcy flow within the rock matrix, hydraulic fractures propagation, and fluid leak-off into the formation are simultaneously taking into account in the model. Then, the model is validated by comparing the results with available analytical solutions. To understand and quantify the poroelastic effects on the propagation of hydraulic fracture, several cases with different matrix permeability, leak-off coefficients, and bulk modulus of pore fluid are performed. The simulation results show that the total volume of leakage is controlled by the combined action of matrix permeability and leak-off coefficient. The fracture aperture and length decrease with the increase of matrix permeability or leak-off coefficient, while as the bulk moduli of pore fluid increases, the fracture aperture and length tend to increase.
Analysis of reservoir geological characteristics and development countermeasures
Authors: Zheng Hong
Published: March 2023

Under the background of the continuous improvement of the scale of modern petroleum engineering construction in our country, the level of oilfield development technology has been improved in an all-round way, which provides sufficient resources for the development of society. In the process of oilfield development, it is necessary to do a good job in the analysis of the geological characteristics of the reservoir to clarify the basic geological characteristics of the reservoir, based on which the development of the oilfield can improve the scientific work of reservoir development. Therefore, it is necessary to strengthen the analysis of geological characteristics and strengthen the innovation of exploration and development technology. Therefore, this paper will conduct in-depth research and analysis on the geological characteristics of the reservoir and development countermeasures, and summarize some measures based on practical experience, in order to be helpful to the related engineering.
Adjustment of infill in transition zone to improve oilfield productivity
Authors: Long Xu
Published: March 2023

Affected by the high viscosity of crude oil, the large injection-production well spacing, the poor injection condition, and the low oil recovery rate, the overall development effect of transition zone is poor, besides, the low produced degree and the poor utilization of thin oil layer makes transition zone have some potential excavation. Under the condition that the current conventional measures to improve block development are not clear, it is necessary to further optimize the injection-production system. Based on the principle of “Well pattern rules, Well spacing optimization, Injection-production perfecting, Facilitation of adjustment”, layer combination is thus optimized. This paper analyzes the effect of encryption adjustment and tracking adjustment.
A Novel Doping Layer Strategy to Realize High Efficiency Laye-by-Layer Organic Solar Cells
Authors: Li Xinrui , Du Xiaoyang , Tao Silu
Published: March 2023

Molecular doping is an effective mean to achieve high performance organic solar cells (OSCs). However, the introduction of dopants aggravates the problem of morphological complexity in bulk heterojunction (BHJ) OSCs, and the choice of solvent after mixing with the donor and acceptor is greatly limited. Here, we innovatively propose a solution to solve the above problems by inserting a dopant layer between the donor layer and the acceptor layer to construct OSCs with a stacked structure through layer-by-layer (LbL) spin-coating solution method. Compared with the control devices (16.95%), the performance of PM6/PABA/BO-4Cl devices with the addition of the dopant layer 4-Aminobenzoic acid (PABA) was significantly enhanced, achieving an efficiency of 17.46%. Morphological characterization and charge analysis showed that the performance improvement was attribute to the film morphology optimization by the dopant located at the D/A interface, while effectively increasing the exciton dissociation rate and charge mobility of OSCs. Thus, our work demonstrates that the doping layer strategy coupled with sequential solution deposition is an effective way to construct efficient devices and is a promising alternative to BHJ OSCs.
Study on the electrothermal coupling characteristics of different types of thermoelectric units
Authors: Zhong Ziwei , Zhu Lingkai , Zheng Wei , Gong Zhiqiang , Shang Panfeng , Guo Junshan , Liu Jun , Zhang Yanpeng
Published: March 2023

The electric heating characteristics of thermoelectric units refer to the coupling relationship between the generating power P and the steam extraction volume G of the unit for external heating. The heat supply forms of directly regulated public thermoelectric units mainly include steam extraction condensing heat supply and back pressure circulating water heat supply. Through the research on the electrothermal coupling characteristics of different types of thermoelectric units, we can master the electric load output range of thermoelectric units in the heating season, provide data support for the power grid dispatching department, effectively promote the consumption of new energy, and ensure the smooth and orderly supply of electric energy.
Arthroscopic Management of Distal Radius Fractures and
Malunions
Authors: Williams Daniel C , Piñal Francisco del
Published: March 2023

Articular congruity is the most important prognostic factor when dealing with a
distal intra-articular radius fracture or the correction of intra-articular
malunion. This article details our approach with tips and tricks for effectively
managing these complex injuries with the aid of dry arthroscopy.
Die Behandlung der kontrakten ersten Kommissur der Hand:
Literaturübersicht und eigene Erfahrungen
Authors: Fritsche Elmar , Winterholer Dorrit , Hug Urs
Published: March 2023

Der frei bewegliche Daumen ist für die Funktion der menschlichen Hand von
zentraler Bedeutung. Diese Beweglichkeit ist an eine ungestörte Funktion
der Kommissur zwischen dem Daumen und dem Zeigefinger oder bei Fehlen des
Zeigefingers dem Mittelfinger gekoppelt. Eine erhebliche, durch welche Genese
auch immer bedingte Kontraktur der ersten Kommissur hat unweigerlich einen
erheblichen Funktionsverlust bis hin zur nahezu vollständigen
Gebrauchsunfähigkeit des Daumens, ja der Hand zur Folge. Bei der
operativen Behandlung der Kontraktur der ersten Kommissur ist häufig ein
Eingriff an der kontrakten Haut ausreichend. In einigen Fällen bedingt
sie aber ein mehrstufiges Vorgehen an Faszien, Muskeln und Gelenken, an dessen
Ende die Weichteilerweiterung des Interspatiums zwischen Daumen und Zeigefinger
steht. Wir erwähnen alte Einsichten zum Thema, geben einen
Überblick über die Literatur, stellen eigene Erfahrungen anhand
von 5 Fällen vor und geben – der Schwere der Kontraktur
entsprechend – eine Therapieempfehlung ab.
Augentrost (Euphrasia officinalis)
Authors: Dorstewitz Hartmut
Published: March 2023

Augentrost ist eine Heilpflanze, die sich seit vielen Jahrhunderten bewährt hat. Zum Einsatz kommt sie, wie der Name verrät, insbesondere bei Augenerkrankungen.
Psychosomatische Beschwerden: Kopf- und Bauchschmerzen im Kindesalter
Authors: Pothmann Raymund
Published: March 2023

Bauch- und Kopfschmerzen gehören bei Klein- und Schulkindern zu den häufigsten funktionellen Beschwerden. Die Diagnostik orientiert sich am Ausschluss der potenziell wichtigsten somatischen Ursachen, um eine therapeutische Bereitschaft zu gewährleisten. Die Behandlung sollte eingebettet sein in ein biopsychosoziales Gesamtkonzept, das ein verhaltenstherapeutisches Setting sowie eine ausgewogene triggerarme Kost in Anlehnung an traditionelle chinesische Vorgaben einschließt. Der Einsatz von Akupunktur und verwandten Verfahren hängt allerdings eher von der Verfügbarkeit eines qualifizierten Therapeuten als von einer ausgewiesen wirksamen Indikation ab.
Es muss nicht immer Ibu sein – naturheilkundliche Behandlung fieberhafter Erkrankungen
Authors: Stör Wolfram , Schierl Sabine
Published: March 2023

Fieber kann gefährlich sein, ist aber oft auch wichtig für die Entwicklung. Der Beitrag gibt viele praktische Ratschläge, wie fieberhafte Erkrankungen ohne allopathische fiebersenkende Mittel erfolgreich behandelt werden können, besonders bei Kleinkindern und im Vorschulalter, also die Altersgruppe, die häufig fiebert.
Click Chemistry-Inspired Synthesis and Photophysical Studies of Calix[4]arene-Cored Galactosylated and Mannosylated Glycodendrimers
Authors: Kumar Sunil , Yadav Mangal S. , Maddeshiya Tarkeshwar , Asthana Surabhi , Jaiswal Manoj K. , Tiwari Vinod K. , Pandey Mrituanjay D.
Published: March 2023

A prompt and modular copper(I)-catalyzed azide–alkyne cycloaddition ʼclickʼ approach has been exploited for the synthesis of galactose- and mannose-coated calixarene-cored G1 generation glycodendrimers. The developed calixarene glycodendrimers were characterized by using spectral techniques (1H NMR, 13C NMR and IR). In photophysical evaluation, UV and fluorescence spectra of the developed compounds were recorded in CH3CN/H2O.
Visible-Light-Driven Iodine-Catalyzed Synthesis of Unsymmetrical Disulfides via Oxidative Coupling
Authors: Ren Ming-Zhe , Fu Yan-Jun , Quan Zheng-Jun , Wang Xi-Cun , Zhang Bo-Sheng
Published: March 2023

Herein, a facile and environmentally friendly oxidative coupling reaction to obtain unsymmetrical disulfide compounds, without using metal or organic dyes as photocatalyst and only using a catalytic amount of iodine, was developed. Oxygen is used as oxidant in the reaction and the substrate scope is wide. A gram-scale synthesis also highlights the synthetic practicality of this photochemical strategy. Moreover, our mechanistic studies support the formation of disulfide products through free-radical coupling.
Mucous Extractor for Tumor Tissue Sampling in Neurosurgery
Authors: Ruparelia Jigish , Gosal Jaskaran Singh , Garg Mayank , Jha Deepak Kumar , Kaur Manbir , Kumari Kamlesh
Published: March 2023

Objective Collection of sample for histopathological analysis is highly important during any surgical procedure. The histopathology report helps determine the diagnosis, prognosis further management, and follow-up plan. The use of a reliable sample collection technique is doubly important in neurosurgical procedures because lesions are often deep-seated and difficult to access.

Materials and Methods Conventional techniques of sample collection, such as use of tumor-grasping forceps and collection of material from the ultrasonic aspirator device suffer from limitations of access and unreliability. We propose a novel technique of sample collection using readily available mucous aspirator device.

Results This device is economical, sterile, and disposable. It can be used even in low-resource settings because it is easily available. It can also be connected to suction cannula and the negative pressure settings can be adjusted as required.

Conclusion The use of this device for neurosurgical procedures has been tried in the transcranial and transnasal neurosurgical procedures and found to be effective. The sample collected in the canister of the mucous aspirator can be directly sent to the laboratory for histopathological analysis.
Evaluation of Radiological and Neurological Outcomes after Anterior Cervical Corpectomy with Fusion using Expandable Cage Alone and Expandable Cage with Anterior Cervical Plating
Authors: Seervi Manoj Kumar , Jain Surendra , Purohit Devendra Kumar , Meena Ugan Singh
Published: March 2023

Objective After anterior cervical corpectomy expandable cage were used with or without using anterior cervical plate for structural support are being preferred over autologous bone graft and other types of cages. Nowadays, the preferable type of cages and application of anterior cervical plate remain a debatable topic with studies giving divergent results. The purpose of this study is to evaluate the outcomes of expandable cages used alone or expandable cage used with anterior cervical plate following anterior cervical corpectomy.

Materials and Methods This study was conducted on 100 patients from January 2019 to December 2021 and all patients were undergone anterior cervical corpectomy and fusion and divided in two groups with expandable cage only (Group A) and expandable cage with anterior cervical plate (Group B). Various long-term benefits and radiological outcomes were studied in both groups.

Statistical Analysis and Results In this study, 100 patients were included and all patients underwent corpectomy followed by insertion of expandable cage alone or with anterior cervical plate. There was an improvement in C2–C7 Cobb's angle in group B was significantly higher than group A (p < 0.05) and decrease in Nurick's scale score in group B was significantly higher than group A (p < 0.05). The outcomes were measured with fusion rate (94%), subsidence rate (15%) and change in C2–C7 Cobb's angle was 4 degrees in this study.

Conclusion Expandable cage with or without anterior cervical plate was used after anterior cervical corpectomy for various cervical pathological conditions. In this study, we conclude the long-term benefits and radiological outcomes of two groups as expandable cage was used alone or with additional application of anterior cervical plate. In this study, the results were more in favor of additional application of anterior cervical plate as compared with expandable cage alone and more studies were required in future for more established long-term benefits and drawbacks.
Accuracy and Safety of Fluoroscopy-Assisted Transpedicular Screw Insertion in Thoracolumbar Spine Surgery: Evaluation of 122 Screws
Authors: Sahri Imad-Eddine , Tlemcani Zakaria Chandid , Akroud Sofia El , Cherif El Asri Abad , Gazzaz Miloudi
Published: March 2023

The objective of this study is to determine the accuracy and safety of trans-pedicular screws' insertion in the thoracolumbar spine using a fluoroscopy-assisted surgical technique. We retrospectively evaluated all patients who underwent a postoperative computed tomography scan to assess the location of the pedicular screws following thoracolumbar spinal surgery, at the Mohammed Vth Military Training Hospital-Rabat, from January 2020 to April 2022. We used Gertzbein's classification to grade pedicular cortex breaches. A screw penetration greater than 4 mm (grades D–E) was considered critical and one less than 4 mm was classified as noncritical (grades A–C). A total of 122 screws inserted in the T1 to L5 vertebrae were included from 25 patients. The average age was 46 years old. Pathologies included degenerative disorders (5 patients), tumors (8 patients), and trauma (12 patients). All screws were inserted using lateral and anteroposterior fluoroscopic guidance. A total of 11 transpedicular screws breaches were identified. The breaches incidence was significantly higher in thoracic pedicles (8 screws) than in lumbar pedicles (3 screws). Of these, three critical cases occurred in two patients and one of them required reintervention. The remaining eight exceedances were not critical and were closely monitored and followed up. Transpedicular screws fluoroscopy-assisted surgical fixation can be performed for the stabilization of the thoracolumbar spine with satisfactory safety and precision.
Malignant Peripheral Nerve Sheath Scalp Tumor: A Short-Term Institutional Experience with Literature Review
Authors: Jha Vikas Chandra , Alam Mohammad Shahnawaz , Sinha Vivek Saran
Published: March 2023

Malignant peripheral nerve sheath tumor (MPNST) of the scalp is rare. These lesions are associated with neurofibromatosis type 1 (NF1), but patients had been reported without NF1 also. We tried to analyze the difference between the clinical course and outcome of the patient with MPNST having stigmata of NF1 and without it. We included five patients treated over 3 years between July 2018 and July 2021 with diffuse scalp MPNST. Two of these five patients with MPNST of the scalp had neurocutaneous stigmata of NF1. Three were female and two males with an average age of 38.40 ± 18.48 years—the youngest with NF1 being a 19-year-old female. We found dull aching pain as the most typical complaint in all patients and a repeated episode of generalized seizure in one patient. In these cases, two patients with NF1 have highly vascular tumors and attained large sizes greater than 30 cm. These two cases required preoperative digital subtraction angiography (DSA) and embolization with n-butyl acrylate. Total excision of the tumor was done in all patients with radiotherapy. Metastases within 1 year were noted in two patients with NF1, and one of these two succumbed to her illness. The rest of the three patients without NF1 are under follow-up with no evidence of disease with a maximum follow-up of 2 years. Large MPNST (size > 20 cm) are rare and reported to have been associated with and without NF1. Patients with scalp MPNST with NF1 can achieve larger size with fast progression of tumor size and higher chances of recurrence and metastases.
Invariant tori of full dimension for a nonlinear Schrödinger equation with an almost periodic potential
Authors: Rui Jie
Published: March 2023

In this paper, we study a nonlinear Schrödinger equation with an almost-periodic potential, subject to periodic boundary conditions. Under appropriate assumptions on the potential, we obtain many small-amplitude, time-almost-periodic solutions for the equation. We improve the Kolmogorov–Arnold–Moser iteration to reduce the almost-periodic potential, especially depending on the space variables. The analysis of the nonlinear perturbation is also the key argument.
The electron cyclotron drift instability: A comparison of particle-in-cell and continuum Vlasov simulations
Authors: Tavassoli Arash , Papahn Zadeh Mina , Smolyakov Andrei , Shoucri Magdi , Spiteri Raymond J.
Published: March 2023

The linear and nonlinear characteristics of the electron cyclotron drift instability (ECDI) have been studied through the particle-in-cell (PIC) and continuum Vlasov simulation methods in connection with the effects of the azimuthal length (in the E ×B direction) on the simulations. Simulation results for a long azimuthal length (17.82 cm =627 vd/ωce, where ωce is the electron cyclotron frequency and vd is the E × B drift of the electrons) are reported, for which a high resolution is achieved in Fourier space. For simulations with a long azimuthal length, the linear growth rates of the PIC simulations show a considerable discrepancy with the theory, whereas the linear growth rate of the Vlasov simulations remains close to the theory. In the nonlinear regime, the inverse cascade is shown in both PIC and Vlasov simulations with a sufficiently large azimuthal length. In simulations with a short azimuthal length, however, the inverse cascade is barely observed. Instead, the PIC simulations with a short azimuthal length (0.5625 cm =19.8 vd/ωce) show an essentially continuous nonlinear dispersion, similar to what is predicted by the ion-sound turbulence theory. It is shown that, in the PIC and Vlasov simulations, the inverse cascade coincides with the formation and merging of electron structures in phase space. This process, however, terminates differently in the PIC simulations compared with the Vlasov simulations. Larger amplitudes of ECDI fluctuations are observed in the PIC simulations compared with the Vlasov simulations, leading to an intensified electron heating and anomalous current. This suggests that the statistical noise of PIC simulations might contribute to the extreme electron heating that has been observed in previous studies.
Enhanced resistive switching uniformity in HfO2/TiO2 NWA memristor for synaptic simulation
Authors: Sun Yudong , Wang Jing , He Dong , Yang Menghua , Jiang Changzhong , Li Wenqing , Xiao Xiangheng
Published: March 2023

In this article, we fabricated a memristive device with a Cu/HfO2/TiO2 nanowire array (NWA)/FTO structure through a hydrothermal method and atomic layer deposition. The devices exhibit good resistive switching properties, including low set voltages (∼1 V), good retention (>104 s), and multilevel storage. Compared with the Cu/TiO2 NWA/FTO device, Cu/HfO2/TiO2 NWA/FTO devices exhibit better uniformity, which could be due to the difference between the dielectric constants of TiO2 and HfO2. Under the application of consecutive voltage pulses, some synaptic functions were mimicked, including long-term potentiation/depression, paired-pulse facilitation, and spike timing dependent plasticity.
Analytical results for enhancement factor (EF) of surface enhanced Raman spectroscopy (SERS) for two metallic spheres and nano-shells
Authors: Ben-Aryeh Y.
Published: March 2023

Interactions between symmetric two metallic spheres and an electromagnetic (EM) field polarized in the symmetric axis are described. Spherical symmetries of the present systems are exploited by the use of bi-spherical coordinates. Boundary conditions are applied, which assume a very large negative value for the dielectric constant of special metals. The EM field in small gaps (in hotspots) is amplified by many orders of magnitude relative to the external field. Analytical results for the maximal enhancement factor in surface enhanced Raman spectroscopy for two metallic spheres and two nano-shells are obtained as a function of various parameters. The calculations are based on potentials derived by using an electrostatic model, which is valid for very small particles.
Depressed MEG causality analysis based on polynomial kernel Granger causality
Authors: Qian Jing , Yao Wenpo , Bai Dengxuan , Wang Qiong , Wang Shuwang , Zhou Ang , Yan Wei , Wang Jun
Published: March 2023

In this study, we employ the Granger causality of a polynomial kernel to identify the coupling causality of depressed magnetoencephalography (MEG). We collect MEG under positive, neutral, and negative emotional stimuli and focus on the β-band activities. According to test results, depressed people display stronger left–right symmetrical interconnection in their prefrontal and occipital lobes under nonpositive stimuli(namely neutral and negative stimuli), indicating that they are more sensitive to nonpositive stimuli. The intensity of the right occipital information flow is higher in depressed people. We also see the Granger causality index increased in the occipital–frontal areas of depressed patients under negative stimuli. In general, detecting the polynomial kernel Granger causality of the MEG can effectively characterize the strength of the interconnected brain regions in depressed patients, which can be used as a clinical diagnosis aid.
Language practices and policies of Singaporean-Japanese families in Singapore
Authors: Cavallaro Francesco , Tan Yan Kang , Xie Wenhan , Ng Bee Chin
Published: March 2023

The few studies on Family Language Policy in Singapore (FLP) have generally focused on FLP in local and immigrant
Chinese families. This article explores language policies that seem to undergird Singaporean-Japanese families’ language
practices. In-depth interviews and observations with five such families showed that Japanese only functions as the language of
communication between the Japanese parents and their children if parents have invoked particular language policies to support its
transmission and use at home. For most families, English was the main medium of communication among family members. Language
policies and practices in these families were heavily influenced by the value emplaced on each language within the parents’
linguistic repertoire and their beliefs regarding language learning.
VMP1 prevents Ca2+ overload in endoplasmic reticulum and maintains naive T cell survival
Authors: Liu Ying , Ma Yuying , Xu Jing , Zhang Guangyue , Zhao Xiaocui , He Zihao , Wang Lixia , Yin Na , Peng Min
Published: March 2023

Ca2+ in endoplasmic reticulum (ER) dictates T cell activation, proliferation, and function via store-operated Ca2+ entry. How naive T cells maintain an appropriate level of Ca2+ in ER remains poorly understood. Here, we show that the ER transmembrane protein VMP1 is essential for maintaining ER Ca2+ homeostasis in naive T cells. VMP1 promotes Ca2+ release from ER under steady state, and its deficiency leads to ER Ca2+ overload, ER stress, and secondary Ca2+ overload in mitochondria, resulting in massive apoptosis of naive T cells and defective T cell response. Aspartic acid 272 (D272) of VMP1 is critical for its ER Ca2+ releasing activity, and a knockin mouse strain with D272 mutated to asparagine (D272N) demonstrates all functions of VMP1 in T cells in vivo depend on its regulation of ER Ca2+. These data uncover an indispensable role of VMP1 in preventing ER Ca2+ overload and maintaining naive T cell survival.
Atomic structure evolution and linear regression fitting models for pre-breakdown electric field strength of FCC, BCC and HCP metal nano-emitters under high electric field from PIC-ED–MD simulations
Authors: Gao Xinyu , Li Nan , Song Zifeng , Wu Kai , Cheng Yonghong , Xiao Bing
Published: March 2023

Multi-scale and multi-physics simulations are carried out for nano-emitters consisting of FCC (Al, Cu and Au), BCC (V, Mo and W) and HCP (Ti, Zn and Zr) metals, using hybrid electrodynamics coupled with molecular dynamics-particle in cell simulations (PIC-ED–MD). We show that the tilting of the nano-emitter at low temperature and small electric field (E-field) is mainly caused either by the movement of partial dislocations at the apex of the nanotip or by the elastic local distortions of atomic registries away from their ideal lattice sites (FCC/BCC/HCP). At high E-field, the intense resistive heating due to the strong electron emission leads to the direct melting of the apex of nano-emitters. For nano-emitters consisting of low melting point metals such as Al, Zn and Au, the thermal runaway is driven by the elongation, thinning and necking of the molten region. Meanwhile, the elongation, thinning and sharpening produce the nano-protrusion at the apex of metal nano-emitters, and the detachment of atoms or atomic clusters from the nano-protrusion mainly contributes to the thermal runaway event for refractor metals such as Ti, Zr, Mo and W. The critical E-field strength of metal nano-emitters is found to be strongly correlated with structural parameters (atomic coordination number of liquid and equilibrium lattice constant), thermodynamic quantities (cohesive energy and enthalpy of evaporation) and phase transition temperatures (melting point and boiling point). These correlations enable us to establish either single-variable linear fitting models or multi-variable linear regression models to predict the critical E-field value for metal nano-emitters with good credibility.
Strategically constructed high-reflectivity multiple-stack distributed Bragg reflectors for efficient GaN-based flip-chip mini-LEDs
Authors: Shi Lang , Sun Yuechang , Cui Yongjin , Du Peng , Zhuang Jiaming , Zhou Shengjun
Published: March 2023

Full-angle distributed Bragg reflectors (DBRs) consisting of numerous sub-DBRs with discrete central wavelengths have been developed to enhance performance of GaN-based flip-chip mini light-emitting diodes (FC mini-LEDs). However, relatively low reflectivity of full-angle DBRs at large angle incidence restricts further enhancement in performance of FC mini-LEDs. Here, we introduce a reflectivity optimization strategy for constructing high-reflectivity multiple-stack DBRs by rationally engineering the number of sub-DBRs and adjusting central wavelength distribution of sub-DBRs. Based on the reflectivity optimization strategy, we devise a Ti3O5/SiO2 quintuple-stack DBR which is composed of five sub-DBRs. Our quintuple-stack DBR maintains a high reflectivity (>97.5%) over a wide range of incident angles of light. Notably, compared with the full-angle DBR, our quintuple-stack DBR exhibits higher reflectivity at large angle incidence and thinner multilayer thickness. Furthermore, we demonstrate two types of GaN-based blue FC mini-LEDs with indium-tin oxide (ITO)/quintuple-stack DBR and ITO/full-angle DBR p-type ohmic contacts. Benefiting from superior reflection performance, blue FC mini-LED with ITO/quintuple-stack DBR achieves an enhancement of ∼5.8% in light output power at 10 mA, in comparison with blue FC mini-LED with ITO/full-angle DBR. Our work signifies an advancement towards high-reflectivity DBRs, which enables higher-performance FC mini-LEDs.
Synthesis and applications of MXene-based composites: a review
Authors: Noor Umar , Mughal Muhammad Furqan , Ahmed Toheed , Farid Muhammad Fayyaz , Ammar Muhammad , Kulsum Umme , Saleem Amna , Naeem Mahnoor , Khan Aqsa , Sharif Ammara , Waqar Kashif
Published: March 2023

Recently, there has been considerable interest in a new family of transition metal carbides, carbonitrides, and nitrides referred to as MXenes (Ti3C2T
x
) due to the variety of their elemental compositions and surface terminations that exhibit many fascinating physical and chemical properties. As a result of their easy formability, MXenes may be combined with other materials, such as polymers, oxides, and carbon nanotubes, which can be used to tune their properties for various applications. As is widely known, MXenes and MXene-based composites have gained considerable prominence as electrode materials in the energy storage field. In addition to their high conductivity, reducibility, and biocompatibility, they have also demonstrated outstanding potential for applications related to the environment, including electro/photocatalytic water splitting, photocatalytic carbon dioxide reduction, water purification, and sensors. This review discusses MXene-based composite used in anode materials, while the electrochemical performance of MXene-based anodes for Li-based batteries (LiBs) is discussed in addition to key findings, operating processes, and factors influencing electrochemical performance.
Estimation of patient-size dependent imaging dose for stereoscopic/monoscopic real-time kV image guidance in lung and prostate SBRT
Authors: Abeywardhana Ruwan , Spurway Alan , Sattarivand Mike
Published: March 2023

Purpose. The purpose of this work is to quantify the dependence of patient-specific imaging dose on patient-size from ExacTrac stereoscopic/monoscopic real-time tumor monitoring during lung and prostate stereotactic body radiotherapy (SBRT). Approach. Thirty lung and 30 prostate SBRT patients that were treated with volumetric modulated arc therapy (VMAT) were selected and divided into three patient size categories. Imaging doses from all SBRT fractions were calculated retrospectively assuming patients went through real-time tumor monitoring during their actual VMAT treatment times. Treatment times were divided into periods of stereoscopic and monoscopic real-time imaging depending on the imaging view with linac gantry blockage. The computed tomography (CT) images and contours of the planning target volume (PTV) and organs at risk (OARs) were exported from the treatment planning system. Based on the CT data, patient-specific 3D imaging dose distributions were calculated in a validated Monte Carlo model using DOSEXYZnrc. Vendor-recommended imaging protocols (lung: 120–140 kV, 16–25 mAs; prostate: 110–130 kV, 25 mAs) were used for each patient size category. Patient-specific imaging doses received by PTV and OARs were evaluated using dose volume histograms, dose delivered to 50% of organ volume (D50), and 2% of organ volume (D2). Results. Bone and skin received the highest imaging dose. For the lung patients, the highest D2 for bone and skin were 4.30% and 1.98% of the prescription dose respectively. For prostate patients, the highest D2 were 2.53% and 1.35% of the prescription for bone and skin. Additional imaging dose to PTV as a percentage of the prescribed dose was at most 2.42% for lung and 0.29% for prostate patients. T-test results showed statistically significant difference in D2 and D50 between at least two patient size categories for PTVs and all the OARs. Larger patients received more skin dose in both lung and prostate patients. For the internal OARs, larger patients received more dose in lung treatment while the trend was opposite in prostate treatment. Conclusion. Patient-specific imaging dose was quantified for monoscopic/stereoscopic real-time kV image guidance in lung and prostate patients with respect to patient size. Additional skin dose was 1.98% (in lung patients) and 1.35% (in prostate patients) of the prescription which is within 5% recommended value by the AAPM Task Group 180. For internal OARs, larger patients received more dose in lung patients while the trend was the opposite for prostate patients. Patient size was an important factor to determine additional imaging dose.
Optical properties of donor impurity in Yukawa like potential: application to SiGe/Si and Si/SiGe
Authors: Varsha  , Kria M , Nautiyal Vijit V , Lakaal K , Laroze D , Pérez L M , Prasad V , Feddi E
Published: March 2023

We have investigated the effect of temperature and geometrical confinement on the behavior of spherical cavities with Yukawa potential presence inside the cavity within effective mass approximation. Using the Finite-element method, we have calculated the energy eigenvalue with the geometric and temperature effects into consideration with consideration of temperature and position-dependent mass, and position-dependent dielectric constant. The optical transition from the ground to the excited state shows a blueshift in optical absorption coefficient, refractive index changes, and second and third harmonic generation with an increase in temperature. The increase in the geometric size of the spherical cavity causes a redshift in the optical resonance peaks.