bluuebunny/crossref_metadata_2025 huggingface dataset:
Asymmetric multi-band reflective metasurface for linear and circular polarizations conversion in Ku, K, Ka, and U bands
Authors: Zafar Jamal , Khan Humayun Zubair , Jabbar Abdul , Kazim Jalil ur Rehman , Rehman Masood Ur , Siddiqui Adil Masood , Abbasi Qammer H. , Imran Muhammad Ali
Published: February 2025

This work proposes a novel multi-band reflective metasurface, that is capable of linear polarization (LP), and circular polarization (CP) conversion in Ku, K, Ka, and U Bands. The metasurface design involves a combination of ring and square elements strategically arranged, and printed on a 0.76 mm thin-grounded Rogers RO3003 substrate. The metasurface achieves LP for y-polarized incident electromagnetic (EM) wave in 16.2–17.2 GHz, 23.0–25.4 GHz, 40.3–54.35 GHz frequency bands. The polarization conversion ratio (PCR) for LP frequency ranges is minimum 90% with an fractional bandwidth (FB) of 2.94%, 9.91%, and 26.9%, respectively. Moreover, metasurface achieves CP for y-polarized incident EM wave in 16.1–16.55 GHz, 17.5–22.15 GHz, 26.65–37.75 GHz, and 55.6–59.8 GHz frequency bands. In addition, the axial ratio (AR) for CP frequency ranges is less than 3 dB with a FB of 2.75%, 23.45%, 34.47%, and 7.27%. The device performance is considerably stable under oblique incidences up to 45 degrees. The metasurface unitcell is compact with a structural size of
$$\text {length}=0.23\lambda _\circ$$
,
$$\text {width}=0.23\lambda _\circ$$
and
$$\text {thickness}=0.08\lambda _\circ$$
. The proposed prototype is fabricated, and the measured results are in good agreement with the simulated one. Overall, the proposed metasurface exhibits promising performance characteristics and holds potential for multiple applications in satellite based networks.
Development of a wireless electroretinogram recording system
Authors: Man Tony T. C. , Yip Yolanda W. Y. , Pang Chi Pui , Brelén Mårten Erik
Published: February 2025

A novel device consisting of amplifiers, an analogue-digital converter, offset correction units, and a microcontroller with Bluetooth wireless functionality was fabricated. Electroretinography (ERG) recordings were captured in dark-adapted and light-adapted full-field flash stimulations in an anaesthetised animal model using the novel wireless system. Recordings were repeated using a standard ERG recording setup of the Espion E3 system for comparison. The electroretinogram signal a-wave and b-wave amplitudes, peak times, signal offset, potential drift, and power line noise were compared between the recording setups. Signals from the novel system were found to have similar waveforms to those recorded from the standard ERG setup. There were no significant differences in the a-wave amplitudes (P > 0.43), a-wave peak times (P > 0.61) and b-wave peak times (P > 0.55). The offset potential drift when using the novel system was significantly smaller than the reference system (P < 0.02). The novel system also showed stronger resilience against powerline noise interference, as evidenced by a statistically significant performance increase during recordings with substantial noise interference (P < 0.01). The on-source signal processing and wireless transmission can improve the quality of recorded ERG signals. Our study demonstrates a proof of concept for performing wireless ERG recordings, which enhance the performance by reducing noise and potential drift in the recorded signals.
Spin-dependent thermoelectric properties of a hybrid ferromagnetic metal/quantum dot/topological insulator junction
Authors: Trocha Piotr
Published: February 2025

The thermoelectric properties of hybrid system based on a single-level quantum dot coupled to a ferromagnetic metallic lead and attached to the surface states of a three-dimensional topological insulator are theoretically investigated. On the surface of a three-dimensional topological insulator, massless helical Dirac fermions emerge. We calculate the thermoelectric coefficients, including electrical conductance, Seebeck coefficient (thermopower), heat conductance, and the figure of merit, using the nonequilibrium Green’s function technique. The results are analyzed in terms of the emergence of new effects. The calculations are performed within the Hubbard I approximation concerning the dot’s Coulomb interactions. Additionally, the spin-dependent coupling of the quantum dot to the ferromagnetic lead lifts the spin degeneracy of the dot’s level, which influences the transport properties of the system. We incorporate this effect perturbatively to obtain the spin-dependent renormalization of the dot’s level. We also consider the case of finite spin accumulation in the ferromagnetic electrode, which leads to spin thermoelectric effects.
Niacinamide and its impact on stratum corneum hydration and structure
Authors: Sjöberg Thomas , Fsahaye Andebrhan , Nilsson Emelie J. , Letasiova Silvia , Namro Itedale , Visdal-Johnsen Lene , Hrapovic Nina , Smiljanic Sandra , Österlund Christina , Engblom Johan , Björklund Sebastian
Published: February 2025

Niacinamide (NIA) is widely used in skincare for its favorable safety profile, anti-aging effects, and proven clinical efficacy in treating various skin conditions. However, its direct impact on the hydration and molecular organization of the stratum corneum (SC), the primary skin barrier, remains unclear. This study examines how NIA influences the SC’s lipid matrix organization, soft keratin structure, and water sorption behavior across varying relative humidity (RH) levels. Using small- and wide-angle X-ray diffraction and dynamic vapor sorption measurements, we compared NIA-treated SC samples to untreated controls under different RHs. The main findings show that while NIA is non-hygroscopic, it enhances water uptake of the SC at high humidity (95% RH). At low humidity (60% RH), NIA swells the keratin monomer spacing, although the SC water content remains low, suggesting a plasticizing effect that could increase SC flexibility in dry conditions. NIA also modifies the diffraction intensities from the lipid matrix differently at 60% and 95% RH, implying that it interacts with the SC lipid matrix and influences the water distribution within the SC lipid and protein domains. These effects appear independent of the investigated dose regime, indicating a specific concentration threshold. Overall, NIA shows distinct interaction with keratin, swelling the spacing between keratin monomers in dry conditions, without acting as a traditional keratolytic agent.
Analyzing the influence of manufactured sand and fly ash on concrete strength through experimental and machine learning methods
Authors: Sathvik S , Oyebisi Solomon , Kumar Rakesh , Shakor Pshtiwan , Adejonwo Olutosin , Tantri Adithya , Suma V
Published: February 2025

River sand supplies are decreasing due to overexploitation and illicit sand mining. One ton of Portland cement production (the main binder in concrete) emits about one ton of carbon dioxide into the atmosphere. Thus, this study replaced conventional cement and river sand (R sand) with recycled waste materials (fly ash and manufactured sand (M sand)). The concrete mix proportions were designed using M40 grade, and the Ordinary Portland cement (OPC) and R sand were replaced with 0–85 wt% of fly ash and 0-100 wt% of M sand. The concrete samples were tested for compressive strength after 3–90 days of curing. Furthermore, machine learning (ML) techniques were engaged to predict the compressive strength of the concrete samples using Extreme Gradient Boosting (XGBoost), Long Short-Term Memory (LSTM), Support Vector Machine (SVM), and Gaussian Process Regression (GPR). Besides, the concrete samples containing fly ash, M sand, and R sand were characterized for microstructures and elemental compositions using SEM-EDS. The results revealed improved concrete compressive strength by incorporating fly ash and M sand. After 28 days of curing, OPC and R sand were partially replaced with 25 and 50 wt% of fly ash and M sand attained the designed strength of M 40 grade concrete. XGBoost model yielded the most accurate performance metrics for forecasting the compressive strength in training and testing phases with R2 values equal to 0.9999 and 0.9964, respectively, compared to LSTM, SVM, and GPR. Thus, the XGBoost approach can be a viable technique for forecasting the strength of concrete incorporating fly ash and M sand. SEM-EDS analyses revealed compact formations with high calcium and silicon counts. Thus, the XGBoost approach can be a viable technique for forecasting the strength of concrete incorporating fly ash and M sand.
Pharmacological CDK4/6 inhibition promotes vulnerability to lysosomotropic agents in breast cancer
Authors: Nehme Jamil , Maassen Sjors , Bravaccini Sara , Zanoni Michele , Gianni Caterina , De Giorgi Ugo , Soto-Gamez Abel , Altulea Abdullah , Gheorghe Teodora , Wang Boshi , Demaria Marco
Published: February 2025

Breast cancer is a leading cause of mortality worldwide. Pharmacological inhibitors of cyclin-dependent kinases (CDK) 4 and 6 (CDK4/6i) inhibit breast cancer growth by inducing a senescent-like state. However, the long-term treatment efficacy remains limited by the development of drug resistance, so clearance of senescent-like cancer cells may extend the durability of treatment. However, we show here that while CDK4/6i-treated breast cancer cells exhibit various senescence-associated phenotypes, they remain insensitive to common senolytic compounds. By searching for novel vulnerabilities, we identify a significantly increased lysosomal mass and altered lysosomal structure across various breast cancer cell types upon exposure to CDK4/6i in preclinical systems and clinical specimens. We demonstrate that these CDK4/6i-induced lysosomal alterations render breast cancer cells sensitive to lysosomotropic agents, such as L-leucyl-L-leucine methyl ester (LLOMe) and salinomycin. Importantly, sequential treatment with CDK4/6i and lysosomotropic agents effectively reduces the growth of both hormone receptor-positive (HR+) and subsets of triple-negative breast cancer (TNBC) cells in vivo. This sequential therapeutic strategy offers a promising approach to eliminate CDK4/6i-induced senescent(-like) cells, potentially reducing tumor recurrence and enhancing the overall efficacy of breast cancer therapy.
Organoid modeling reveals the tumorigenic potential of the alveolar progenitor cell state
Authors: Li Jingyun , Dang Susanna M , Sengupta Shreoshi , Schurmann Paul , Dost Antonella F M , Moye Aaron L , Trovero Maria F , Ahmed Sidrah , Paschini Margherita , Bhetariya Preetida J , Bronson Roderick , Ho Sui Shannan J , Kim Carla F
Published: February 2025

Cancers display cellular, genetic and epigenetic heterogeneity, complicating disease modeling. Multiple cell states defined by gene expression have been described in lung adenocarcinoma (LUAD). However, the functional contributions of cell state and the regulatory programs that control chromatin and gene expression in the early stages of tumor initiation are not well understood. Using single-cell RNA and ATAC sequencing in Kras/p53-driven tumor organoids, we identified two major cellular states: one more closely resembling alveolar type 2 (AT2) cells (SPC-high), and the other with epithelial-mesenchymal-transition (EMT)-associated gene expression (Hmga2-high). Each state exhibited distinct transcription factor networks, with SPC-high cells associated with TFs regulating AT2 fate and Hmga2-high cells enriched in Wnt- and NFκB-related TFs. CD44 was identified as a marker for the Hmga2-high state, enabling functional comparison of the two populations. Organoid assays and orthotopic transplantation revealed that SPC-high, CD44-negative cells exhibited higher tumorigenic potential within the lung microenvironment. These findings highlight the utility of organoids in understanding chromatin regulation in early tumorigenesis and identifying novel early-stage therapeutic targets in Kras-driven LUAD.
Detection of β-d-glucuronidase activity in environmental samples using 4-fluorophenyl β-d-glucuronide and 19F NMR
Authors: Teriosina Aleksandra , Barsukov Igor L. , Cartmell Alan , Powell Andrew K. , Stachulski Andrew V. , Yates Edwin A.
Published: February 2025

A substrate for the testing of β-glucuronidase enzyme activity in opaque samples by 19F NMR is proposed.
Rapid detection and quantitative analysis of thiram in fruits using a shape-adaptable flexible SERS substrate combined with deep learning
Authors: Wang Hongjun , Bian Ziyang , Wang Yue , Niu Huijuan , Yang Zhenshan , Li Hefu
Published: February 2025

An integrated sensing platform was developed for the rapid and quantitative detection of pesticide residues in fruits. This platform utilizes a thin, shape-adaptable, flexible SERS substrate in conjunction with a 1D CNN model.
Fluorogenic selective detection of Zn2+ using a pyrazole-ortho-vanillin conjugate: insights from DFT, molecular docking, bioimaging and anticancer applications
Authors: Kumar Malavika S. , Pakrashy Sourav , Manna Sounik , Choudhury Sujata Maiti , Das Bhriguram , Ghosh Abhishek , Seikh Asiful H. , Dolai Malay , Das Avijit Kumar
Published: February 2025

A fluorescent sensor, (E)-N′-(2-hydroxy-3-methoxybenzylidene)-3,5-dimethyl-1H-pyrazole-1-carbohydrazide (HMPC), was designed and synthesized for the selective fluorescence recognition of Zn2+ in semi-aqueous media.
“Click” disaggregation-induced emission of a fluorescent dye
Authors: Basran Kaleena , Luedtke Nathan W.
Published: February 2025

A new approach to fluorogenic labelling is demonstrated, where a fluorescent dye undergoes disaggregation-induced emission (DIE) during an azide–alkyne ‘‘click’’ reaction with an azide-containing biopolymer to allow ‘‘no-wash’’ fluorescence imaging.
Exploring the homing effect and enhanced drug delivery potential of small extracellular vesicles
Authors: Zhang Qi , Cao Ke , Ren Ting-Ju , Wu Hao , Xu Zhang-Run
Published: February 2025

sEVs and liposomes were dimerized through non-covalent combination for exploring the homing effect and enhanced drug delivery potential of sEVs.
Graphene quantum dots as supramolecular linkers in metal organic frameworks for constructing metal atom electrocatalysts
Authors: Song Yujie , Li Jiajie , Zhang Yaqi , Lou Jiali , Cui Yuanyuan , Chen Hongwu , Lin Chao , Li Xiaopeng , Fan Huilin , Song Xiaokai
Published: February 2025

A new strategy has been developed to effectively stabilize single cobalt sites in ZIF-67-derived hierarchical porous carbon with the assistance of N-GQDs.
Phenoxazine-based covalent organic frameworks as a turn-off fluorescent probe for trace water detection in organic solvents
Authors: Cui Fengmin , Zhang Yingdi , Liu Benhai , Jing Zerong , Du Ya
Published: February 2025

Phenoxazine-based COFs exhibit wide characteristic ICT and show better selective response to water in THF with low detection limits.
2-Aminopyridine nucleobases enable DNA invasion by peptide nucleic acid clamps under physiological conditions
Authors: Tessier Brandon R. , Rozners Eriks
Published: February 2025

Peptide nucleic acid (PNA) clamps modified with 2-aminopyridine (M) nucleobase invaded double-stranded DNA under physiological salt conditions.
Construction of robust Cu-MOFs from bifunctional pyridine-hydroxamate linkers for photocatalytic CO2 reduction
Authors: Xiong Li , Tang Wenlei , Xiong Chaozhi , Du Jiajun , Zhang Zhiyuan , Qiu Yuqing , Shao Zhen-Wu , Zhou Xuemei , Liu Chong
Published: February 2025

A bifunctional “soft and hard” pyridine-hydroxamate ligand was used to construct a series of robust Cu-MOFs. Theoretical analysis and experimental data revealed the Cu-MOFs’ differential properties and potential for photocatalytic CO2 reduction.
Molecular dynamics simulation on the role of CL5D in accelerating the product dissociation of SIRT6
Authors: Rao Hao , Yang Ting , Wang Yue , Fei Junwen , Bie Li-Hua , Gao Jun
Published: February 2025

CL5D accelerates the dissociation of SIRT6 products, with the 9-mer peptide dissociating first, followed by ADPr.
Self-powered photodetector of GaN/Sc2CCl2 heterojunction with high carrier mobility and polarization sensitivity
Authors: Zhang Guoqing , Cui Zhen , Song Aming , Zhang Shuang , Wang Lu
Published: February 2025

GaN/Sc2CCl2 heterojunction carrier mobility reaches up to 5670 cm2 V−1 s−1 and photocurrent reaches up to 12.78 a02 per photon.
Insight into the thermo-responsive phase behavior of the P1 domain of α-synuclein using atomistic simulations
Authors: Chakraborty Sanchari , Biswas Mithun
Published: February 2025

Biomolecular condensate formation by P1 fragments is regulated by multi-chain interactions between the peptides.
On the stability constants of metal–nitrate complexes in aqueous solutions
Authors: Dinpajooh Mohammadhasan , Hightower Greta L. , Overstreet Richard E. , Metz Lori A. , Henson Neil J. , Govind Niranjan , Ritzmann Andrew M. , Uhnak Nicolas E.
Published: February 2025

Stability constants of simple reactions involving addition of the NO3− ion to hydrated metal complexes, [M(H2O)x]n+ are calculated with a computational workflow developed using cloud computing resources.
A sustainable infrared dry peeling method for shallots (Allium cepa L. aggregatum): comparison of nutritional, enzymatic and sensory characteristics of infrared and conventional peeling methods
Authors: Sakthivel Deepika , Wu Min , Sutar P. P.
Published: February 2025

The impact of traditional and novel infrared peeling methods on shallot quality and sensory attributes was evaluated. Infrared dry peeling was identified as a sustainable method for quality retention.
An octahedral metal oxide nanoparticle-based dual-signal sensing platform for simultaneous detection of histidine and lysine in human blood plasma and urine
Authors: Akhtar Robina , Yaqub Asim , Haq Khan Zia Ul , Jafry Ali Turab , Ajab Huma
Published: February 2025

A single colorimetric probe (NiONPs) enables the detection of histidine and lysine in various samples, exhibiting peroxidase-like activity. Optimization parameters facilitates the detection, achieving a low detection limit with good stability.
Enhanced supercapacitor performance of NaCrSnNiCeO2 and NaCuFeNiCeO2 nanocomposites: a comparative study of electrode materials
Authors: Iman Wardah , Farooq Nosheen , Kanwal Irsa , Ahmad Fawad , Khan Muhammad Imran , Shanableh Abdallah
Published: February 2025

Recent advancements have focused on developing innovative and renewable technologies for energy production and storage.
Understanding the interplay between pH and charges for theranostic nanomaterials
Authors: Ow Valerie , Lin Qianyu , Wong Joey Hui Min , Sim Belynn , Tan Yee Lin , Leow Yihao , Goh Rubayn , Loh Xian Jun
Published: February 2025

Nanotechnology enables targeted theranostics by enhancing imaging and therapy. This review explores advances in pH-induced charge-switchable nanomaterials, their role in drug delivery and imaging contrast, and future directions in the field.
Morphology-tuned MnOx/TiO2 nanocatalysts for recycling PET plastic waste using biomass-derived ethylene glycol
Authors: Swapna Bhattu , Barnabas Madam Bobby , Moni Gogoi Pragya , Bharali Pankaj , Madras Giridhar , Sudarsanam Putla
Published: February 2025

This work elucidated the effect of TiO2 morphology on the structure–activity properties of MnOx/TiO2 nanocatalysts toward developing practically feasible catalytic routes for the plastic recycling industry.
Imidazole-catalyzed construction of bridged bicyclo [3.3.1] ketals via formal [3 + 3]-cycloaddition of naphthols and 2-hydroxyl chromene derivatives
Authors: Budakoti Asha , Jha Priyankar , Verma Meenakshi , Vasudev Prema G. , Gupta Atul
Published: February 2025

Imidazole catalyzed FC-alkylation/ketalization leads to bridged [3.3.1] ketals. Reaction conditions are mild and scalable.
Intrinsic microkinetic effects of spray-drying and SiC co-support on Mn–Na2WO4/SiO2 catalysts used in oxidative coupling of methane
Authors: Lezcano Gontzal , Kulkarni Shekhar R. , Velisoju Vijay K. , Realpe Natalia , Castaño Pedro
Published: February 2025

This paper presents a microkinetic model to evaluate the effects of a silicon carbide (SiC) co-support and the shaping method on Mn–Na2WO4/SiO2 catalysts used for the oxidative coupling of methane.
Fast and scalable continuous flow synthesis of butenolides and coumarins
Authors: Ferreira Lucas Coral , de Souza Galaverna Renan , McBride Tom , Costa e Silva Rodrigo , Browne Duncan L. , Pastre Julio Cezar
Published: February 2025

A unified platform that improves safety and efficiency in producing diverse libraries of compounds and have the potential to speed up the drug discovery process in medicinal chemistry.
Polymer dynamics at low molecular weight of poly(butylene oxide) star polymers
Authors: Bichler Karin J. , Jakobi Bruno , Schneider Gerald J.
Published: February 2025

Star polymers are an interesting class of polymers to study based on their shape and dynamics. We use complementary techniques to study the polymer dynamics of star polymers with shorter side chains and compare them with linear counterparts.
Exploiting rice industry wastewater for more sustainable sunlight-driven photocatalytic hydrogen production using a graphitic carbon nitride polymorph
Authors: Bianchini Petra , Profumo Antonella , Cerri Lorenzo , Tedesco Costanza , Malavasi Lorenzo , Speltini Andrea
Published: February 2025

Towards a greener hydrogen production by photocatalytic treatment of rice industry wastewater.
Development of a novel polyelectrolyte complex nanocomposite of modified chitosan and karaya gum for co-delivery of 5-fluorouracil and curcumin for cancer therapy
Authors: Anjar Rakshitha , Mahadev Manohar , Charyulu Rompicherla Narayana , Badalamoole Vishalakshi
Published: February 2025

A pH-responsive polyelectrolyte complex of trimethylchitosan and carboxymethylkaraya gum containing silver nanoparticles has been developed as a matrix material for co-delivery of the drugs, 5-fluorouracil and curcumin.
Application of silk fibroin-based composite films in biomedicine and biotechnology
Authors: Ma Ke , Wu Zhi-Feng , Chen Ke-Zheng , Qiao Sheng-Lin
Published: February 2025

This article provides a comprehensive examination of recent advancements in silk fibroin-based composite films, with a focus on their applications in bone regeneration, wound healing, and health monitoring.
Intense and repeatable orange mechanoluminescence of Mn2+ activated CaGa4O7 for visualized mechanics sensing
Authors: He Yongwen , Wang Jie , Fang Shaofan , Qin Junshan , Feng Long , Tian Birong , Feng Shaowei , Wang Zhaofeng
Published: February 2025

This work reports the mechanoluminescence of CaGa4O7:Mn2+ in terms of relatively long wavelength, high brightness, repeatability, and mechanical responsiveness, which can penetrate biological tissue for visualized biomechanics sensing.
Thermodynamics-inspired identification of privileged organocatalysts for hydrogen evolution reactions
Authors: Zhang Yu-Shan , Zhong Bing , Dong Likun , Yang Jin-Dong , Cheng Jin-Pei
Published: February 2025

The thermodynamics of diazaphospholenes suggest a good balance between hydricity and regeneration capacity (via electron reduction), inspiring us to identify privileged organocatalysts for electrochemical hydrogen evolution reactions.
Puppeteering the reactivity of frustrated Lewis pairs toward CO2via coordination dichotomy in bridging units
Authors: Faizan Mohmmad , Pawar Ravinder
Published: February 2025

The coordination dichotomy of the o-carborane cage has been investigated as a strategy to regulate the frustration in frustrated Lewis pairs (FLPs).
Direct chemical lithography writing on 2D materials by electron beam induced chemical reactions
Authors: Danylo Iryna , Koláčný Lukáš , Kissíková Kristína , Hartman Tomáš , Pitínová Martina , Šturala Jiří , Sofer Zdeněk , Veselý Martin
Published: February 2025

Direct electron beam lithography is studied for targeted platinum nanoparticle deposition onto 2D supports, which allows an evaluation of the unique influence of nanoparticle–support interactions on enhanced catalytic activity.
Synthesis and electrochemical evaluation of Ti and V-based carbide MXene via microwave assisted hydrofluoric acid etching for energy storage
Authors: Lokhande P. E. , Rednam Udayabhaskar , Kadam Vishal , Jagtap Chaitali , Padalkar S. R. , Bhat Rohini , Boobalan T. , Al-Asbahi Bandar Ali
Published: February 2025

The current study involves the synthesis of bimetallic (Ti,V) carbide MXene through microwave-assisted hydrofluoric acid etching, targeting supercapacitor applications.
Structural and electronic properties of graphene-like GeC3 under mechanical strain: a DFT study
Authors: Ain Noor Ul , Kanwal Arooba , Aftab Tayyaba , Jalil Abdul , Aamir Muhammad
Published: February 2025

Owing to low carrier mobility and instability at low dimensions, traditional semiconductors, such as silicon, are becoming impractical for sharp-performance, minimal-power electronic applications.
Palladium(ii)/Lewis acid catalyzed oxidative olefination of 2-benzamidopyridine 1-oxide with acrylates: synthesis of isoindolinones
Authors: Patel Dharmik M. , Patel Raj N. , Rathod Nileshkumar B. , Patel Sachinkumar D. , Thakur Dinesh G. , Sonawane Mahesh A. , Ghosh Subhash Chandra
Published: February 2025

This work describes the development of a heterobimetallic Pd(ii)/Cu(ii)-catalyzed C–H olefination of 2-benzamidopyridine 1-oxide with acrylates followed by intramolecular aza-Michael addition to construct the desired isoindolinone core.
Deconstructing poplar lignin from ionic liquid pretreatment for biological conversion through sulfonation and Fenton chemistry
Authors: Martinez Daniella V. , Rodriguez Alberto , Choudhary Hemant , Salinas Jay , Martinez Estevan J. , Davydovich Oleg , Geiselman Gina M. , Gladden John M. , Simmons Blake A. , Kent Michael S.
Published: February 2025

We present a method for depolymerization of poplar lignin for microbial conversion via sulfonation and Fenton chemistry.
Correction: Mixed metal–antimony oxide nanocomposites: low pH water oxidation electrocatalysts with outstanding durability at ambient and elevated temperatures
Authors: Luke Sibimol , Chatti Manjunath , Yadav Asha , Kerr Brittany V. , Kangsabanik Jiban , Williams Tim , Cherepanov Pavel V. , Johannessen Bernt , Tanksale Akshat , MacFarlane Douglas R. , Hocking Rosalie K. , Alam Aftab , Yella Aswani , Simonov Alexandr N.
Published: February 2025

Correction for ‘Mixed metal–antimony oxide nanocomposites: low pH water oxidation electrocatalysts with outstanding durability at ambient and elevated temperatures’ by Sibimol Luke et al., J. Mater. Chem. A, 2021, 9, 27468–27484, https://doi.org/10.1039/D1TA07293E.
The 3D morphology of open clusters in the solar neighborhood
Authors: Qin C. , Pang X. , Pasquato M. , Kouwenhoven M. B. N. , Vallenari A.
Published: February 2025

We analyzed the fractal dimension of open clusters using 3D spatial data from Gaia DR 3 for 93 open clusters from Pang et al. and 127 open clusters from Hunt & Reffert mainly within 500 pc. The box-counting method was adopted to calculate the fractal dimension of each cluster in three regions: the all-member region, r ≤ rt (inside the tidal radius), and r > rt (outside the tidal radius). In both the Pang and Hunt catalogs, the fractal dimensions are smaller for the regions r > rt than those for r ≤ rt, indicating that the stellar distribution is more clumpy in the cluster outskirts. We classified cluster morphology based on the fractal dimension via the Gaussian mixture model. Our study shows that the fractal dimension can efficiently classify clusters in the Pang catalog into two groups. The fractal dimension of the clusters in the Pang catalog declines with age, which is attributed to the development of tidal tails. This is consistent with the expectations from the dynamical evolution of open clusters. We found strong evidence that the fractal dimension increases with cluster mass, which implies that higher-mass clusters are formed hierarchically from the mergers of lower-mass filamentary-type stellar groups. The transition of the fractal dimension for the spatial distribution of open clusters provides a useful tool to trace the Galactic star-forming structures, from the location of the Local Bubble within the solar neighborhood to the spiral arms across the Galaxy.
A filament eruption on the RS CVn-type star UX Ari
Authors: Cao Dongtao , Gu Shenghong
Published: February 2025

Context. Stellar flares can be accompanied by filament or prominence eruptions, which may lead to stellar coronal mass ejections (CMEs) that have significant impacts on surrounding exoplanets and stellar evolution.

Aims. We report the capture of a filament eruption associated with an optical flare on the RS CVn-type star UX Ari.

Methods. Based on high-resolution spectroscopic observations, we investigated the Doppler-shifted absorption features appeared in the Hα flaring spectra, which can be indicative of a filament eruption.

Results. A huge optical flare was observed, which lasted for at least 150 hours and released an energy of about 1.47 × 1037 erg in the Hα line. The corresponding bolometric white-light energy is converted to be 1.03 × 1039 erg, indicating that the flare is comparable to the most intense stellar superflares. A blueshifted absorption feature with a bulk velocity of −143.9 km s−1 emerged in the Hα line region during the initial phase of the flare, which then decelerated and turned into redshifted absorption. This suggests that a filament eruption happened and ultimately fell back toward the star, suggesting that it represents a failed filament eruption. The erupted filament mass of 8.5 − 15.0 × 1020 g and the kinetic energy of 8.8 − 15.5 × 1034 erg are derived. Furthermore, the relationship between the filament eruption and the flare is likely characterized by a sympathetic eruption.
Flaring activities of fast rotating stars have a solar-like latitudinal distribution
Authors: Yang Huiqin , Cheng Xin , Liu Jifeng , Liu Shuai , Zhao Zhanhao , Zhou Guiping , Hou Yijun , Gao Changliang , Niu Zexi
Published: February 2025

Context. The dynamo theory has always been one of the biggest mysteries in stellar physics. One key reason for its uncertainty is poor knowledge of the dynamo process on stars other than the Sun. The most important observed feature of the solar dynamo is that active regions only appear at low latitudes, which provides a crucial constraint to the dynamo theory, while with Doppler imaging, the current technique to spatially resolve the stellar hemisphere, it is difficult to distinguish the equatorial region. As a consequence, the latitudinal distribution of active regions (LDAR) of stars is ambiguous and controversial, mainly due to the limitations of the current technique for spatially resolving the stellar surface.

Aims. Fast rotating stars, which are young and active, are thought to operate with a different dynamo process than the Sun. We study their LDAR and compare them with the Sun to reveal the underlying dynamo process.

Methods. Flares are drastic and observational activity events that occur in active regions. Here, we propose a new method for studying how the apparent flaring activity varies with respect to the inclination to determine the LDAR of fast rotating stars.

Results. We find that the LDAR of fast rotating stars is consistent with that of the Sun, contrary to expectations. Our results provide a crucial constraint to the stellar dynamo, indicating that the solar-like dynamo also applies to fast rotating stars, and even spans different stages of their evolution.
Multi-band study of the flaring mode emission in the transitional millisecond pulsar PSR J1023+0038
Authors: Baglio M. C. , Coti Zelati F. , Hughes A. K. , Carotenuto F. , Campana S. , de Martino D. , Motta S. E. , Papitto A. , Rea N. , Russell D. M. , Torres D. F. , Di Marco A. , La Monaca F. , Covino S. , Giarratana S. , Illiano G. , Miraval Zanon A. , Alabarta K. , D’Avanzo P. , Messa M. M.
Published: February 2025

We present a comprehensive study of the flaring mode of the transitional millisecond pulsar (tMSP) PSR J1023+0038 during its X-ray sub-luminous state, using strictly simultaneous X-ray, UV, optical, and radio observations. The X-ray flares exhibit UV and optical counterparts and coincide with the brightest radio flare observed in the past decade, reaching 1.2 mJy at 6 GHz and lasting ∼1 hour. During the flare, the optical polarisation drops from ≃1.4% to ≃0.5%, indicating the emergence of an unpolarised component. We propose that the thickening of the disc, which enlarges the shock region between the pulsar wind and the accretion flow and may drive the X-ray flaring observed in tMSPs, enhances the ionisation level of the disc, thereby generating an increased number of free electrons. These electrons could then be channelled by magnetic field lines into the jet. This increased jet mass-loading could drive the associated radio and optical variability. The radio spectral evolution during flares is consistent with synchrotron self-absorption in jet ejecta or internal shocks within the compact jet. We infer radio polarisation upper limits (< 8.7%, < 2.3%, and < 8.2%, before, during, and after the radio flare) that further support a compact jet origin but do not rule out discrete ejections. Our findings suggest that tMSPs could serve as essential laboratories for investigating jet-launching mechanisms, mainly because they operate under very low mass accretion rates. This accretion regime has not been explored before in the context of accretion-ejection coupling.
Pullback attractors for two dimensional magnetohydrodynamic equations with delays in sub-linear operators
Authors: Song Xiaoya , Zhao Chunxiang
Published: February 2025

The paper concerns the asymptotic dynamics for two dimensional magnetohydrodynamic (2D MHD) equations with delays in sub-linear operators. First, we propose some appropriate assumptions of delays and establish the well-posedness of weak solutions. Then, the process U(·, ·) generated by the weak solutions is constructed in MH2(=H×LH2). Finally, we prove the existence of a compact pullback attractor.
New bounds for heat transport in internally heated convection at infinite Prandtl number
Authors: Arslan Ali , Rojas Rubén E.
Published: February 2025

We prove new bounds on the heat flux out of the bottom boundary, FB, for a fluid at infinite Prandtl number, heated internally between isothermal parallel plates, under two kinematic boundary conditions. In uniform internally heated convection, the supply of heat equally leaves the domain entirely by conduction in the absence of a flow. When the heating, quantified by the Rayleigh number, R, becomes sufficiently large, turbulent convection ensues, reducing the heat leaving the domain through the bottom boundary. In the case of no-slip boundary conditions, with the background field method, we prove that FB≳R−2/3−R−1/2⁡log(1−R−2/3), up to a positive constant independent of the Rayleigh and Prandtl numbers. Whereas between stress-free boundaries we show that, FB≳R−40/29−R−35/29⁡log(1−R−40/29). We perform a numerical study of the system in two dimensions up to a Rayleigh number of 5 × 109 using the spectral solver Dedalus. The numerical investigations indicate that FB∼R−0.092 and FB∼R−0.12 for the two kinematic boundary conditions respectively. The gap between the bounds and simulations, along with the constructions used in the proofs highlight the potential for further optimisation of bounds for FB in internally heated convection.
Generalized Fourier transform and action-angle variables for the local/nonlocal derivative nonlinear Schrödinger equations
Authors: Zhang Yu , Tian Shou-Fu
Published: February 2025

In this work, we present the generalized Fourier transform and action-angle variables for the local/nonlocal derivative nonlinear Schrödinger equations. The generalized Fourier transform, derived from the completeness relation, serves as the expansion of any Schwartz function in terms of solutions to the Lax spectral problem. We establish the completeness relations for squared solutions to the Lax spectral problem and determine the Poisson brackets between the scattering data. Action-angle variables, expressed through the scattering data, are constructed based on these Poisson brackets. It is noteworthy that the analyticity of scattering data differs from that of the AKNS-type spectral problem, necessitating adjustments to the integral paths when deriving the completeness relations. Interestingly, the conservation laws for the equation can be expressed in terms of either the spectral parameter or the potential functions, revealing the connection between the potential functions and the scattering data.
Linear stability analysis of the Couette flow for the two dimensional Euler–Poisson system
Authors: Pu Xueke , Zhou Wenli , Bian Dongfen
Published: February 2025

This paper is concerned with the linear stability analysis for the Couette flow of the Euler–Poisson system for both ionic fluid and electronic fluid in the domain T×R. We establish upper and lower bounds of the linearized solutions of the Euler-Poisson system near Couette flow. In particular, inviscid damping for the solenoidal component of the velocity is obtained.
Epidemic dynamics with awareness cascade of positive and negative information on delayed multiplex networks
Authors: Bao Haibo , He Ye
Published: February 2025

Human behavioral awareness is usually socially relevant, decisions are made based on the behavior of individuals, and this dynamic process of human awareness with herd effects is called awareness cascade. Based on the complexity of modern information dissemination, information is not monolithic. Individuals choose the type of epidemic-related information to accept, i.e., whether it is positive or negative information, according to the awareness cascade, and then take the corresponding measures to cope with the epidemic. In this paper, we use the microscopic Markov chain approach to model an information-virus dual network, where the information layer has a threshold model with awareness cascade of positive and negative information, and on the virus layer is a susceptible-infected-recovery model with epidemic infection time delay and recovery time delay. The time delay is also a non-negligible modeling factor as the complete infection of an individual and the complete recovery of an individual require sufficient time. An explicit formula for the critical threshold of epidemic spread for this model is derived. We find that positive and negative information and time delay have a significant effect on the critical threshold, and the recovery time delay is the time delay that mainly affects the epidemic size. Experiments show that the local acceptance rate of positive information has a threshold point for the spread of epidemics under awareness cascade, and that this point is significantly affected by the mass media. The local acceptance rate of negative information also divides the spread of epidemics into two stages.
Can the Doppler be useful for a benchmark analysis of the wave-like properties of memory-dependent telegraphers’ equation
Authors: Pietrzak Tobiasz , Górska Katarzyna , Horzela Andrzej , Kocarev Ljupco
Published: February 2025

Telegraphers’ equation perturbed by a uniformly moving external harmonic impact is investigated to uncover information useful for distinguishing properties of the time evolution patterns that describe either memoryless or memory-dependent modeling of transport phenomena. Memory effects are incorporated into telegraphers’ equation by smearing the first- and second-order time derivatives so that the memory kernel smearing the second-order time derivative acts as the smeared derivative of the smeared first-order time derivative. Such a generalized telegraphers’ equation (abbreviated as GTE) is solved under initial conditions that specify the values of the solutions and their time derivatives taken at the initial time and boundary conditions that require the sought solutions to vanish either at the x space infinity or the (+l)/(−l) boundaries of a compact domain. The question is which solutions would be classified as traveling or standing waves. To answer this, we consider the Doppler effect and investigate how the frequency and velocity of external sources influence the obtained solutions. Using the short-time Fourier transform allows us to advance the problem and shows that infinite domain solutions to the GTEs, provided by a model example involving the Caputo fractional derivatives CDt2α and CDtα with 0<α≤1, exhibit a kind of velocity-dependent Doppler-like frequency shift if 12<α≤1. The effect remains unnoticed if 0<α≤12. This confirms our previous hypothesis that the emergence of wave-like effects in solutions of fractional equations is related to the occurrence of fractional time derivatives of the order greater than 1.
Pressure drop of slug flow in horizontal pipes with different pipe
diameters and liquid viscosities
Authors: Cao Yeqi , Xu Qiang , Yu Haiyang , Li Yuwen , Huang Bo , Guo Liejin
Published: February 2025

Accurate prediction of the horizontal slug pressure drop is valuable for optimizing the multiphase pipeline transport process and ensuring the stable operation of the pipeline systems and treatment facilities. Experimental slug pressure drop research is conducted based on differential pressure signals in the short (0.065 m ID, 215D) and long (0.046 m ID, 35 957D) horizontal pipes. A slug pressure drop database in horizontal pipes is constructed over a wider range of pipe diameters (0.030–0.3 m), liquid viscosities (0.0101–6.25 Pa⋅s), and pipe lengths (6–1657 m). The slug pressure drop increases with decreasing pipe diameter, while the distribution range of slug pressure drop vs the superficial gas velocity rises with increasing liquid viscosity. The 26 pressure drop prediction models are evaluated for their ability in the horizontal slug pressure drop database with different pipe structures and fluid properties, and the best pressure drop correlations are selected for the low, medium, and high liquid viscosity ranges. Accordingly, a combined pressure drop prediction approach of horizontal slug flow based on liquid viscosity classification is proposed with a Pearson's correlation coefficient of 0.987, and the average absolute percentage error is reduced from 44.98% to 30.14%. Based on the Lockhart–Martinelli method, a prediction correlation for horizontal slug pressure drop is developed over a wider range of pipe diameters and liquid viscosities, and industrial near-horizontal pressure drop data are successfully predicted with 89.6% of the data in the error interval of ±20%.
Handling the asymmetric spectral line profile: application to hydrogen Lyman-α transition
Authors: Solovyev D , Anikin A , Zalialiutdinov T
Published: February 2025

This paper discusses some features of the spectral line profile theory used in the treatment of measured atomic transitions. It is shown that going beyond the established linear approximation for the spectral line contour in the case of its nonresonant extension, the potential for a more accurate extraction of atomic characteristics from experimental data arises. Using the example of the Lyman-α (Ly
α
) transition in hydrogen, a simple analysis of the observed spectral line distorted by a possible interfering transitions is given. In particular, the results obtained in the present work clearly demonstrate that the processing of the same experimental data at different settings can provide an accurate determination of the transition frequency, the centre of gravity as well as the hyperfine splitting of the ground state in hydrogen-like atomic systems. The latter is especially important for setting up precision spectroscopic experiments on the antihydrogen atom.
Impact of stray field on spin-transfer torque and voltage controlled magnetic anisotropy assisted spin–orbit torque magnetic RAMs
Authors: Dutta Ramit , Jahan Parash Hayder , Zunaid Baten Md
Published: February 2025

Spin–orbit torque magnetic random-access memory (SOT-MRAM) has recently garnered significant attention as an emerging non-volatile memory technology. While designing SOT-MRAM arrays, it is essential to account for magnetic coupling with neighboring SOT-MRAMs (inter-cell), as well as within the MRAM itself (intra-cell), to assess their overall performance characteristics. In this work, we investigate the impact of intra- and inter-cell magnetic coupling induced stray fields on the switching characteristics of SOT-MRAMs. The magnetization dynamics of SOT-MRAMs have been analyzed based on the Landau–Lifshitz–Gilbert equation using a micro-magnetic simulation framework, while the Write/Read performances have been evaluated by solving the two-dimensional Fokker–Planck equation. Simulation results show that both during spin-transfer torque-assisted and voltage-controlled magnetic anisotropy (VCMA)-assisted switching, intra-cell coupling has a greater impact than inter-cell coupling. In the presence of stray fields, the write performance improves in one switching direction or the other depending on the reference layer magnetization, whereas the read operation is essentially unaffected. Furthermore, between the two switching techniques, VCMA-assisted switching demonstrates better performances during Write operations—both in the presence and absence of magnetic coupling.
Voltage dependence of dielectric permittivity in zinc oxide varistors under time-varying AC fields
Authors: Xiao Xinyan , Shi Yuhao , Yang Lanjun
Published: February 2025

The aging stability and performance monitoring of zinc oxide (ZnO) surge arresters have attracted considerable attention in the field of electrical engineering. However, the practical performance of existing solutions remains suboptimal. A key factor contributing to this limitation is the lack of sufficient research on the conductive properties of surge arresters and varistors. In time-varying alternating current (AC) fields, ZnO varistors exhibit nonlinear volt-ampere characteristics distinct from those in direct current (DC) fields. Such complex nonlinearity results in challenges in pertinent investigations. In this study, we experimentally investigated the AC response of ZnO varistors under varying voltage amplitudes and frequencies. Subsequently, their dynamic dielectric permittivities were calculated using appropriate models and equations. Moreover, building upon an in-depth exploration of their nonlinear response and dielectric properties, we developed relevant theories (e.g. dielectric relaxation) to analyze influencing factors and underlying mechanisms reasonably. Finally, we linked the relaxation of interfacial charges at the microscopic level with the macroscopic nonlinear characteristics and elaborated on the conduction mechanism in AC fields through the dynamic behavior of nonequilibrium charges in interfacial states. Our findings demonstrate that the dielectric permittivity of ZnO varistors exhibits a voltage dependence in time-varying AC fields, providing valuable insights into their aging stabilities. These insights will provide a foundation for improving the design, performance, and aging stability monitoring of ZnO varistors in surge arresters.
Anomalous angle dependence of superconducting diode effect in a mixed spin-orbit coupling system
Authors: Huang Chuan-Shuai , Lin Weinan , Lu Xiancong
Published: February 2025

In noncentrosymmetric superconductors with strong spin–orbit coupling (SOC), an external magnetic field can induce the superconducting diode effect (SDE) characterized by the helical superconductivity. In this paper, we explore the intrinsic SDE in a superconductor with both Rashba and Dresselhaus SOCs and highlight the role of magnetic field direction in the nonreciprocal helical superconductivity. Numerical results reveal that the magnitude of the field-induced Cooper-pair momentum, which is relevant for the helical superconductivity, exhibits a strong anisotropy when the direction angle of the in-plane magnetic field is varied. This anisotropy, in turn, gives rise to a complex angle dependence of the SDE. Our results can be directly tested experimentally and pave the way for realizing SDE in mixed-SOC systems.