bluuebunny/crossref_metadata_2025 huggingface dataset:
Perioperative Considerations in Patients with Vein of Galen Malformation Undergoing Embolization–A Single-Institution Case Series
Authors: Patel Shivani , Diaz-Rodriguez Natalia , Steppan Jochen
Published: April 2024

Vein of Galen malformation (VOGM) is a congenital, intracranial vascular malformation, with an extracardiac shunt. Neonates can present with high output cardiac failure, pulmonary hypertension, or multiorgan failure and are at high risk of perioperative complications, especially in remote locations. We conducted a retrospective single-center analysis of the perioperative management of patients with VOGM presenting for embolization. Patients were identified by querying both the hospital billing dataset using International Classification of Diseases-10 diagnosis or billing code and the Neuro-interventional Radiology Database, from January 2011 to March 2020. As many as 14 patients were identified, 12 of which underwent definitive treatment. Six patients who underwent embolization in the neonatal period had pulmonary hypertension. Those children required varying degrees of hemodynamic and respiratory support preoperatively and experienced significant intraoperative events, including one intraoperative cardiac arrest. Caring for these critically ill patients in a remote location requires proper planning to prevent adverse outcomes.
Masculine enjoyment problematizing subjectification through norm critique as a response to climate change
Authors: Olsson Josefin
Published: April 2024

This article problematizes subjectification through the practice of norm critique. The study builds on interviews with some of the key initiators and participants in a project working norm critically with men and masculinity in relation to gender equality and climate change in Sweden. Through the psychoanalytical framework of enjoyment and fantasy, I develop a perspective on how and why a certain understanding of the norm-critical subject emerges. The analysis makes visible how the practice of norm critique, while challenging hegemonic masculine norms such as emotional stoicism, reinforces neoliberal ideals of individualized self-emancipation and the quest for authenticity and wholeness, which risks de-politicizing the issue of climate change.
The effect of substrate-induced defects on structural and resistive switching properties in Gd0.2Ca0.8MnO3 thin films
Authors: Angervo I. , Antola A. , Schulman A. , Huhtinen H. , Paturi P.
Published: April 2024

Gd0.2Ca0.8MnO3 thin films were deposited on various substrate materials and their structural and resistive switching (RS) properties were investigated. The deposition resulted in epitaxial and polycrystalline films, with the latter also exhibiting distorted film surfaces. Both epitaxial and a part of polycrystalline films used as RS devices showed consistent RS performance in which an order of magnitude, or higher, switching ratios were achieved between high and low resistance states. The devices showed strong endurance during repeated switching cycles. However, under retention characterization, the resistance states did not remain distinguishable in devices constructed on polycrystalline films, while other devices maintained separable resistance states. The RS results are discussed in relation to the structural characteristics of the films, and this work helps us understand the RS mechanisms that still remain elusive in manganite-based devices.
Epithelial and mesenchymal phenotypes determine the dynamics of circulating breast tumor cells in microfluidic capillaries under chemotherapy-induced stress
Authors: Du Rong , Han Xiaoning , Deng Linhong , Wang Xiang
Published: April 2024

Circulating tumor cells (CTCs) with different epithelial and mesenchymal phenotypes play distinct roles in the metastatic cascade. However, the influence of their phenotypic traits and chemotherapy on their transit and retention within capillaries remains unclear. To explore this, we developed a microfluidic device comprising 216 microchannels of different widths from 5 to 16 μm to mimic capillaries. This platform allowed us to study the behaviors of human breast cancer epithelial MCF-7 and mesenchymal MDA-MB-231 cells through microchannels under chemotherapy-induced stress. Our results revealed that when the cell diameter to microchannel width ratio exceeded 1.2, MCF-7 cells exhibited higher transit percentages than MDA-MB-231 cells under a flow rate of 0.13 mm/s. Tamoxifen (250 nM) reduced the transit percentage of MCF-7 cells, whereas 100 nM paclitaxel decreased transit percentages for both cell types. These differential responses were partially due to altered cell stiffness following drug treatments. When cells were entrapped at microchannel entrances, tamoxifen, paclitaxel, and high-flow stress (0.5 mm/s) induced a reduction in mitochondrial membrane potential (MMP) in MCF-7 cells. Tamoxifen treatment also elevated reactive oxygen species (ROS) levels in MCF-7 cells. Conversely, MMP and ROS levels in entrapped MDA-MB-231 cells remained unaffected. Consequently, the viability and proliferation of entrapped MCF-7 cells declined under these chemical and physical stress conditions. Our findings emphasize that phenotypically distinct CTCs may undergo selective filtration and exhibit varied responses to chemotherapy in capillaries, thereby impacting cancer metastasis outcomes. This highlights the importance of considering both cell phenotype and drug response to improve treatment strategies.
Assessment of the influence of flushing on the wear and morphological properties of the tool during electrical discharge machining
Authors: Das Shirsendu , Paul Rajdeep , Bhowmik Abhijit , Giri Jayant , Albaijan Ibrahim , Prakash Chander
Published: April 2024

The present study is an integrated approach of experimental and simulation processes to investigate the influences of the flushing on the wear, textural feature, heat dissipation, tool-tip temperature, and elemental contents of the electrical discharge machining-tool. The general heat transfer equation in cylindrical coordinates is used to explain the thermal phenomenon through the tool, where the boundary conditions are influenced by convective interactions and dimensionless numbers. The inter-electrode flushing is considered a micro-channel flow, and the used model is conceptualized from “Hazen–Poiseuille observation.” It is observed that the adopted model has a prediction error of 8.503% and can accurately explain the thermal consequences of the process. The study reveals that tool wear is influenced by flushing velocity and flushing pressure. The tool-tip temperature reduces with the Reynolds number, and effectual expelling of the debris can be ensued with a flushing of a higher Reynolds number (Re). However, the increment of Re beyond 4500 provides rapid heat dissipation, which produces extensive residual stress and creates cracks on the surface.
Spheroids formation in large drops suspended in superhydrophobic paper cones
Authors: Mohapatra Omkar , Gopu Maheshwar , Ashraf Rahail , Easo George Jijo , Patil Saniya , Mukherjee Raju , Kumar Sanjay , Mampallil Dileep
Published: April 2024

The utilization of 3D cell culture for spheroid formation holds significant implications in cancer research, contributing to a fundamental understanding of the disease and aiding drug development. Conventional methods such as the hanging drop technique and other alternatives encounter limitations due to smaller drop volumes, leading to nutrient starvation and restricted culture duration. In this study, we present a straightforward approach to creating superhydrophobic paper cones capable of accommodating large volumes of culture media drops. These paper cones have sterility, autoclavability, and bacterial repellent properties. Leveraging these attributes, we successfully generate large spheroids of ovarian cancer cells and, as a proof of concept, conduct drug screening to assess the impact of carboplatin. Thus, our method enables the preparation of flexible superhydrophobic surfaces for laboratory applications in an expeditious manner, exemplified here through spheroid formation and drug screening demonstrations.
The far infrared absorption spectrum of D216O, D217O, and D218O: Experimental line positions, empirical energy levels and recommended line lists
Authors: Mikhailenko S. N. , Karlovets E. V. , Koroleva A. O. , Campargue A.
Published: April 2024

The far infrared absorption spectra of D216O, D217O, and D218O are analyzed with improved accuracy and sensitivity in the 50–720 cm−1 range corresponding to the rotational band. Four room-temperature absorption spectra of highly deuterated water vapor were recorded at the SOLEIL synchrotron by high-resolution Fourier transform spectroscopy. Line centers are reported with a typical accuracy of 5 × 10−5 cm−1 for well isolated lines. The combined line list of about 9700 water lines was assigned to about 10 400 transitions of the nine stable water isotopologues (H2XO, HDXO, D2XO, with X = 16, 17, and 18). A total of 2885 transitions of eight bands involving the first five vibrational states were assigned to D216O. Among them, 2057 are newly reported. The obtained set of transition frequencies was merged with literature data to generate a new set of empirical energy levels for the first five vibrational states of D216O. A total of 1089 transitions of the (000)–(000) and (010)–(010) bands were measured for D217O. They were merged with literature sources to derive 724 empirical term values of seven vibrational states, up to 8088 cm−1. 348 D217O levels are newly determined. A set of 1150 transitions belonging to the (000)–(000) and (010)–(010) bands was measured for D218O. 3451 empirical energies of rotation–vibration levels up to 9222 cm−1 were retrieved using our observations and literature sources. The extension and accuracy of the derived empirical energy levels allow us to recommend new line lists with empirically corrected line positions for D216O, D217O, and D218O.
Artificial tactile system for pressure monitoring in extracorporeal circulation processes
Authors: Ji Zhenhua , Yang Shang , Shi Guoning , Wu Ting
Published: April 2024

Current intraoperative pressure monitoring methods still face significant limitations in perception and feedback, struggling to strike a balance between precision and wearable flexibility. Inspired by biological skin, we propose a biomimetic tactile sensing system for pressure monitoring during extracorporeal circulation, comprising flexible pressure sensors and artificial synaptic transistors. Aimed at addressing the aforementioned issues, our system employs a pyramid-shaped elastic design for flexible pressure sensors, utilizing biocompatible materials polydimethylsiloxane and multi-walled carbon nanotubes as the strain-sensitive layer. This configuration boasts ultra-high sensitivity and resolution (115 kPa−1), accurately detecting subtle pressure changes, such as blood circulation wall pressures. With artificial synaptic transistors as the information processing core, our system successfully simulates crucial neural processing functions, including excitatory post-synaptic currents and double-pulse facilitation, while providing alerts for abnormal blood pressure signals. This system facilitates real-time data processing at the device edge, reducing power consumption, improving efficiency, and better addressing the demands of large-scale physiological pressure data processing. It presents a significant reference for future developments in biomedical electronics and bionics.
The germ theory revisited: A noncentric view on infection outcome
Authors: Carlsson Fredric , Råberg Lars
Published: April 2024

The germ theory states that pathogenic microorganisms are responsible for causing infectious diseases. The theory is inherently microbe-centric and does not account for variability in disease severity among individuals and asymptomatic carriership—two phenomena indicating an important role for host variability in infection outcome. The basic tenet of the germ theory was recently challenged, and a radically host-centric paradigm referred to as the “full-blown host theory” was proposed. According to this view, the pathogen is reduced to a passive environmental trigger, and the development of disease is instead due to pre-existing immunodeficiencies of the host. Here, we consider the factors that determine disease severity using established knowledge concerning evolutionary biology, microbial pathogenesis, and host–pathogen interactions. We note that the available data support a noncentric view that recognizes key roles for both the causative microbe and the host in dictating infection outcome.
How do I love thee? The five love attitudes people hold toward their pets
Authors: Guthrie Michelle F. , Marshall Philip H.
Published: April 2024

Relationship processes in the human-pet relationship parallel those in the human romantic relationship. In this study, we sought to determine whether the six human romantic love styles – Eros (ideal), Storge (friendship), Ludus (game-playing), Pragma (practical), Mania (obsessive, dependent) and Agape (selfless), represented the human-pet relationship. We wrote 44 pet-human love style items, derived from the Love Attitudes Scale (Hendrick and Hendrick,
1986
). Participants (
N
= 254) completed these 44 pet love style items, along with measures of romantic love styles, general pet attitudes, and pet and romantic relationship satisfaction. We reduced the 44 items to the following five factors: Eros/Storge, Ludus, Pragma, Mania, and Agape. The pet love attitudes were modestly correlated with human romantic love attitudes suggesting people endorse different love attitudes in different relationships. Multiple regression results showed that Eros/Storge and Agape were positively correlated with pet relationship satisfaction, while Mania was negatively correlated. Eros/Storge was the strongest predictor of relationship satisfaction (
β
= 0.68). This is the first study to show that love attitudes apply to human-pet relationships and that certain love attitudes predict a happy relationship with one’s pet.
OMA1 protease eliminates arrested protein import intermediates upon mitochondrial depolarization
Authors: Krakowczyk Magda , Lenkiewicz Anna M. , Sitarz Tomasz , Malinska Dominika , Borrero Mayra , Mussulini Ben Hur Marins , Linke Vanessa , Szczepankiewicz Andrzej A. , Biazik Joanna M. , Wydrych Agata , Nieznanska Hanna , Serwa Remigiusz A. , Chacinska Agnieszka , Bragoszewski Piotr
Published: April 2024

Most mitochondrial proteins originate from the cytosol and require transport into the organelle. Such precursor proteins must be unfolded to pass through translocation channels in mitochondrial membranes. Misfolding of transported proteins can result in their arrest and translocation failure. Arrested proteins block further import, disturbing mitochondrial functions and cellular proteostasis. Cellular responses to translocation failure have been defined in yeast. We developed the cell line-based translocase clogging model to discover molecular mechanisms that resolve failed import events in humans. The mechanism we uncover differs significantly from these described in fungi, where ATPase-driven extraction of blocked protein is directly coupled with proteasomal processing. We found human cells to rely primarily on mitochondrial factors to clear translocation channel blockage. The mitochondrial membrane depolarization triggered proteolytic cleavage of the stalled protein, which involved mitochondrial protease OMA1. The cleavage allowed releasing the protein fragment that blocked the translocase. The released fragment was further cleared in the cytosol by VCP/p97 and the proteasome.
The role of the AP-1 adaptor complex in outgoing and incoming membrane traffic
Authors: Robinson Margaret S. , Antrobus Robin , Sanger Anneri , Davies Alexandra K. , Gershlick David C.
Published: April 2024

The AP-1 adaptor complex is found in all eukaryotes, but it has been implicated in different pathways in different organisms. To look directly at AP-1 function, we generated stably transduced HeLa cells coexpressing tagged AP-1 and various tagged membrane proteins. Live cell imaging showed that AP-1 is recruited onto tubular carriers trafficking from the Golgi apparatus to the plasma membrane, as well as onto transferrin-containing early/recycling endosomes. Analysis of single AP-1 vesicles showed that they are a heterogeneous population, which starts to sequester cargo 30 min after exit from the ER. Vesicle capture showed that AP-1 vesicles contain transmembrane proteins found at the TGN and early/recycling endosomes, as well as lysosomal hydrolases, but very little of the anterograde adaptor GGA2. Together, our results support a model in which AP-1 retrieves proteins from post-Golgi compartments back to the TGN, analogous to COPI’s role in the early secretory pathway. We propose that this is the function of AP-1 in all eukaryotes.
Recombinant biosensors for multiplex and super-resolution imaging of phosphoinositides
Authors: Maib Hannes , Adarska Petia , Hunton Robert , Vines James H. , Strutt David , Bottanelli Francesca , Murray David H.
Published: April 2024

Phosphoinositides are a small family of phospholipids that act as signaling hubs and key regulators of cellular function. Detecting their subcellular distribution is crucial to gain insights into membrane organization and is commonly done by the overexpression of biosensors. However, this leads to cellular perturbations and is challenging in systems that cannot be transfected. Here, we present a toolkit for the reliable, fast, multiplex, and super-resolution detection of phosphoinositides in fixed cells and tissue, based on recombinant biosensors with self-labeling SNAP tags. These are highly specific and reliably visualize the subcellular distributions of phosphoinositides across scales, from 2D or 3D cell culture to Drosophila tissue. Further, these probes enable super-resolution approaches, and using STED microscopy, we reveal the nanoscale organization of PI(3)P on endosomes and PI(4)P on the Golgi. Finally, multiplex staining reveals an unexpected presence of PI(3,5)P2-positive membranes in swollen lysosomes following PIKfyve inhibition. This approach enables the versatile, high-resolution visualization of multiple phosphoinositide species in an unprecedented manner.
IRE1α recognizes a structural motif in cholera toxin to activate an unfolded protein response
Authors: Simpson Mariska S. , De Luca Heidi , Cauthorn Sarah , Luong Phi , Udeshi Namrata D. , Svinkina Tanya , Schmieder Stefanie S. , Carr Steven A. , Grey Michael J. , Lencer Wayne I.
Published: April 2024

IRE1α is an endoplasmic reticulum (ER) sensor that recognizes misfolded proteins to induce the unfolded protein response (UPR). We studied cholera toxin (CTx), which invades the ER and activates IRE1α in host cells, to understand how unfolded proteins are recognized. Proximity labeling colocalized the enzymatic and metastable A1 segment of CTx (CTxA1) with IRE1α in live cells, where we also found that CTx-induced IRE1α activation enhanced toxicity. In vitro, CTxA1 bound the IRE1α lumenal domain (IRE1αLD), but global unfolding was not required. Rather, the IRE1αLD recognized a seven-residue motif within an edge β-strand of CTxA1 that must locally unfold for binding. Binding mapped to a pocket on IRE1αLD normally occupied by a segment of the IRE1α C-terminal flexible loop implicated in IRE1α oligomerization. Mutation of the CTxA1 recognition motif blocked CTx-induced IRE1α activation in live cells, thus linking the binding event with IRE1α signal transduction and induction of the UPR.
Long infrared detector based on Se-hyperdoped black silicon
Authors: Tansel T , Aydin O
Published: April 2024

Infrared (IR) detectors play crucial roles in various applications. A significant milestone in advancing the next-generation low-cost silicon technology is the enhancement of hyperdoped black silicon (b-Si) photodetectors, particularly within the IR wavelength range. In this study, highly selenium (Se)-doped b-Si photodetectors. Through the optimization of laser parameters and the application of SiO2 passivation, significant enhancements were achieved in responsivity (R), external quantum efficiency, and specific detectivity (D*) within the long-wave IR range, culminating in a D* of 1.3 × 1012 Jones at 9.5 μm. Additionally, the Se: b-Si photodetectors maintain a D* of approximately 1.3 × 1011 Jones at critical optical telecommunications wavelengths of 1.3 μm and 1.5 μm. These results significantly contribute to the advancement of IR photodetector technology and provide a foundation for the development of highly efficient, low-cost, and broadband IR detectors for Si photonic applications.
Enhanced oxygen reduction activity of α-MnO2 by NH3 plasma treatment
Authors: Li Bing , Liu Xiang , Liu Yuling , Xu Tianjian , He Zhanglong , Liu Shan , Xie Jianan , Chen Yilong , Ning Xiaohui , He Hao
Published: April 2024

Oxygen vacancies and heteroatom doping play important role in oxygen reduction activity of metal oxides. Developing efficient modification method is one of the key issues in catalysts research. Room temperature plasma treatment, with the advantages of mild working conditions, no emissions and high efficiency, is a new catalyst modification method developed in recent years. In this work, hydrothermal synthesized α-MnO2 nanorods are treated in NH3 plasma at room temperature. In the reducing atmosphere, oxygen vacancies and N doping are achieved simultaneously on the surface. The NH3 plasma etched MnO2 demonstrate a significant enhanced oxygen reduction activity with half-wave potential of 0.84 V, limiting current density of 6.32 mA cm−2 and transferred electrons number of 3.9. The Mg–air battery with N-MnO2 display a maximum power density of 76.3 mW cm−2 as well as stable discharge performance. This work provides new ideas for preparing efficient and cost-effective method to boost the catalysts activity.
3D medical image encryption algorithm using biometric key and cubic S-box
Authors: Liu Yunhao , Xue Ru
Published: April 2024

Considering the scarcity of research on 3D medical image encryption, this paper proposes a novel 3D medical image encryption scheme based on biometric key and cubic S-box. To enhance the data security, biometric keys are utilized to overcome the limitations of traditional methods where secret keys with no practical meaning, fixed length, and finite key space, while cubic S-box is constructed to increase the nonlinearity of image cryptosystem. The proposed cryptosystem mainly consists of four phases: pseudo-random sequence generation, confusion, substitution, and diffusion. Firstly, the stepwise iterative algorithm based on coupled chaotic systems is utilized for generating pseudo-random sequences for confusion and diffusion. Secondly, the confusion algorithm based on multiple sorting can scramble pixel positions in 3D images. Thirdly, guided by the designed cubic S-box, pixel substitution is executed sequentially. Lastly, the diffusion algorithm based on ECA and finite field multiplication is capable of increasing the plaintext sensitivity of cryptosystem by concealing the statistical characteristics of plaintext. Simulation experiments performed on multiple 3D medical images demonstrate that the proposed encryption scheme exhibits favorable statistical performance, sufficiently large key space, strong system sensitivity and robustness, and can resist various typical cryptographic attacks.
Wave solutions in (3 + 1)-dimensional generalized fractional mKdV-ZK equation utilizing jacobi elliptic functions
Authors: Elsadany A A , Alshammari Fahad Sameer , Elboree Mohammed K
Published: April 2024

In this research, we investigate the effects of fractional order on the (3 + 1)-dimensional generalized space-time fractional modified KdV-Zakharov-Kuznetsov (mKdV-ZK) equation. We approach the problem by utilizing the conformable fractional derivative. By reducing the mKdV-ZK equation to an integer order nonlinear ordinary differential equation, we apply the Jacobi elliptic function method to find exact solutions. These solutions are specifically tailored for the fractional order of the (3 + 1)-dimensional generalized mKdV-ZK equation, encompassing solitary waves, shock waves, and periodic waves. We also compare these exact solutions with fractional solutions to gain further insights. Notably, our approach demonstrates the feasibility of solving nonlinear time-fractional differential equations with conformable derivatives. Several diagrams have been included to visually depict the behavior of the solutions under fractional order when certain special parameter values are employed.
The Landé g factors of highly charged Sn47+ and Bi80+ ions
Authors: Liu Ming , Li Bing-Bing , Wu Lei , Jiang Jun
Published: April 2024

The wavefunctions and eigenvalues of the ground states of Sn47+, and Bi80+ ions are calculated using the fully relativistic multiconfiguration Dirac-Hartree–Fock (MCDHF) method. Detailed investigation are carried out to study the effects of electron correlation, Breit interaction, quantum electrodynamics (QED), and nuclear recoil. Based on these calculations, the theoretical predictions for the g factors of the ground states of Sn47+ and Bi80+ ions are 1.980429 and 1.934759, respectively. The accuracy of these calculations is expected to be on the order of 10−5.
Comparison of optical absorption and diffuse reflectance spectra techniques for determining the optical energy band gap of dried and calcined Ni0.5Mn0.5Fe2O4 nanoferrite
Authors: Ismail M I M , Faramawy A M
Published: April 2024

Ultrafine particles of Ni0.5Mn0.5Fe2O4 were synthesized by coprecipitation technique to study the effect of both physical forms (ferrofluid and powder) and thermal treatment (drying at 100 °C and calcination at 600 °C for two hours) on the structural properties of Ni0.5Mn0.5Fe2O4 nanoferrite. In addition, the work presents a comparison between using optical absorption and optical diffuse reflectance spectra in studying the optical direct energy band gap. x-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to study the phase, size, and morphology of dried and calcined Ni0.5Mn0.5Fe2O4 nanoparticles, respectively. Fourier transform infrared (FTIR) spectra revealed the characteristic peaks of the synthesized ferrite and provided further information on the functional groups. The optical absorption spectra were used to evaluate the optical direct energy band gap of dried and calcined Ni0.5Mn0.5Fe2O4 nanoferrite as a ferrofluid, whereas, the optical diffuse reflectance spectra were used to evaluate the optical direct energy band gap of dried and calcined Ni0.5Mn0.5Fe2O4 nanoferrite in powder form.
Multiple Fano resonator based on photonic crystal waveguide coupled with two micro-cavities for biomedical sensing application
Authors: Harhouz Ahlam , Tayoub Hadjira , Hocini Abdesselam
Published: April 2024

In order to acquire a miniature refractive index (RI) biosensor with high sensitivity, fast and selective for ultra-low concentrations of molecules, a new Photonic Crystal (PhC) biosensor based on a waveguide coupled to a Fano resonator is proposed for cancer cells detection. An optimized structure of the biosensor can detect cells cancers (Besal, Hela, Jurkat and PC12) in a biological solution deposited on the surface of the resonator. The detection mechanism uses the refractive index as a detection element. The performance of the proposed biosensor is studied by analyzing the variations in the transmission spectrum of different normal and cancer cells. The proposed structure is multimode PhC, with silica as a dielectric material. The finite element method (FEM) have been implemented for studying and investigating the numerical values. The simulation results display that the proposed biosensor attains spectral sensitivities of ‘513.12 nm RIU−1’, ‘587.28 nm RIU−1 ’, ‘702.35 nm RIU−1 ’ and ‘690.57 nm RIU−1 ’ corresponding to Hela cells, PC12 cells, Basal cells and Jurkat cells, respectively. And he qualilty factor Q of the Fano resonance mode can reach 3040.26. Our optimized design ensures easy fabrication with ongoing techniques. This study may open a new way for the development of integrated optical circuits and biosensing.
Electrical properties of epoxy/graphite flakes microcomposite at the percolation threshold concentration
Authors: AlSoud Ammar , Daradkeh Samer I , Shaheen Adel A , Al-Hroub Qasim Amjad , Knápek Alexandr , Mousa Marwan S , Sobola Dinara
Published: April 2024

The electrical properties and activation energy of epoxy/graphite flakes (GFs) micro-composite with different content of GFs (0.0625–1 wt%) were studied for electrical properties using Novocontrol Alpha Analyser (10−2 Hz—107 Hz). GFs sizes ranged from (100 nm to 10 μm). The analysis was performed by scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), visible spectrum reflectance spectra (VIS) spectra, and Fourier Transform Infrared spectra (FTIR) spectroscopy. Increasing GFs content caused multiple changes in electrical characteristics. At 0.0625 wt%, all electrical properties noticeably increased. But at 0.125 to 0.25 wt%, immobilized nanolayers were formed leading to decreased permittivity, dielectric loss (tan(δ)), quality factor (Q-factor), capacitance, conductivity, and figure of merit (F-factor). At 0.25 wt%, the epoxy microcomposite had lower permittivity, tan(δ), conductivity, and capacitance compared with unfilled epoxy. With 0.5 wt% of GFs, signified the percolation threshold, initiating a rise in permittivity, conductivity, capacitance, and tan(δ), accompanied by the closer proximity of grain boundaries, facilitating the formation of conductive channels. At a concentration of 1 wt% of GFs, the establishment of continuous interfacial conductive pathways resulted in a remarkable augmentation of all dielectric properties. The Cole-Cole analysis has been employed to investigate variations in epoxy/GFs microcomposites based on concentration levels.
Numerical simulation on high quality anapole resonator with large electric field concentration in all-dielectric metasurface
Authors: Liu Xiangpeng , Wang Junqiao , Xiong Jing , Wang Qiaoqiao , Zhang Hao , Sun Jingyi
Published: April 2024

In the field of nanophotonics, the manipulation of light using high refractive index dielectric materials has garnered significant attention in recent years. This occurs because dielectric materials with a high refractive index demonstrate lower losses in comparison to metallic plasmonic materials. Furthermore, the interference between internal toroidal dipole moment and electric dipole moment leads to destructive interference in the radiation field, resulting in the formation of an anapole state and localization of energy in the near-field. In this work, we initially excite the anapole state in a silicon nanodisk with a periodic nanostructured disk. By introducing a cross slit and adjusting the structural parameters, the anapole state is further optimized, and achieving highly concentrated near-field energy within the cross air slit of the silicon nanodisk. Specially designed, with a full width at halfmaximum (FWHM) of the transmitted spectrum of only 0.09 nm, and a Q factor of up to 9745, close to 104. Additionally, the structure can produce up to 571 times the electric field enhancement. The remarkable performance of a high Q factor and localized near-field energy holds great potential for various applications, including enhancing nonlinear effects, surface enhanced Raman scattering (SERS) and designing nanolasers.
The CIPM list ‘Recommended values of standard frequencies’: 2021 update
Authors: Margolis H S , Panfilo G , Petit G , Oates C , Ido T , Bize S
Published: April 2024

This paper gives a detailed account of the analysis underpinning the 2021 update to the list of standard reference frequency values recommended by the International Committee for Weights and Measures. This update focused on a subset of atomic transitions that are secondary representations of the second (SRS) or considered as potential SRS. As in previous updates in 2015 and 2017, methods for analysing over-determined data sets were applied to make optimum use of the worldwide body of published clock comparison data. To ensure that these methods were robust, three independent calculations were performed using two different algorithms. The 2021 update differed from previous updates in taking detailed account of correlations among the input data, a step shown to be important in deriving unbiased frequency values and avoiding underestimation of their uncertainties. It also differed in the procedures used to assess input data and to assign uncertainties to the recommended frequency values, with previous practice being adapted to produce a fully consistent output data set consisting of frequency ratio values as well as absolute frequencies. These changes are significant in the context of an anticipated redefinition of the second in terms of an optical transition or transitions, since optical frequency ratio measurements will be critical for verifying the international consistency of optical clocks prior to the redefinition. In the meantime, the reduced uncertainties for optical SRS resulting from this analysis significantly increases the weight that secondary frequency standards based on these transitions can have in the steering of International Atomic Time.
SET sensitivity of a VCRO-based PLL for HL-LHC ATLAS HGTD
Authors: Taille Christophe De La , Dinaucourt Pierrick , Ky Beng-Yun , Morenas Maxime , Seguin-Moreau Nathalie , Thienpont Damien , Vernazza Elena
Published: April 2024

We report the characterization of the Single Effect Transient (SET) sensitivity of an analogue Phase Locked Loop (PLL) based on a Voltage Controlled Ring Oscillator (VCRO) under a proton beam. The clock generator is embedded in a front-end ASIC, namely ALTIROC designed in CMOS 130 nm, reading out Low-Gain Avalanche Diode (LGAD) matrices for the High-Luminosity Large Hadron Collider (HL-LHC). We detail the methodology developed to study such events that could degrade the targeted time resolution of 35 ps per hit. Observed SET-induced phase jumps allow the estimation of the total cross-section of the PLL. The results are extrapolated to the HL-LHC radiation conditions.
Specialized spatially-arranged non-circular fibers enhance filtration performance of African shrimp (Atya gabonensis)
Authors: Liao Yifeng , Lyu Jun , Zhang Yujia , Hong Yuhe , Ding Shuoshuo , Wu Zhigang , Liu Hao , Wu Jianing
Published: April 2024

African shrimp (Atya gabonensis) inhabit clear freshwaters, where the notably low concentration of food may pose a challenge to the efficacy of filter fibers on the chela for filter-feeding. Here, we investigate how the distinctive cross-sectional characteristics and spatial arrangement of the African shrimp’s non-circular fibers contribute to the enhanced filtration performance of these specialized fibers. The unilateral thickening of the wall along the long axis of the elliptical cross-section of African shrimp fibers markedly enhances the filtration performance. The staggered and twisted arrangement of the fibers optimizes the surrounding flow field, achieving a favorable balance between pressure drop and collection efficiency, consequently improving their filtration performance in collecting fine particles (diameter: 2–10 μm). Moreover, the arrangement of the fibers substantially increases the effective flow-facing filtering area of the fiber bundles, thus facilitating their efficiency in collecting larger particles (diameter > 10 μm). The unique fiber properties of the African shrimp offer novel insights for the design and optimization of new fiber-filtering robots, presenting a wide range of potential applications, such as marine in-situ resource extraction, medical filtration, and industrial filtration.
Towards humanlike grasp in robotic hands: mechanical implementation of force synergies
Authors: Teng Zhicheng , Xu Guanghua , Pei Jinju , Li Baoyu , Zhang Sicong , Li Dongwang
Published: April 2024

In the field of robotic hands, finger force coordination is usually achieved by complex mechanical structures and control systems. This study presents the design of a novel transmission system inspired from the physiological concept of force synergies, aiming to simplify the control of multifingered robotic hands. To this end, we collected human finger force data during six isometric grasping tasks, and force synergies (i.e. the synergy weightings and the corresponding activation coefficients) were extracted from the concatenated force data to explore their potential for force modulation. We then implemented two force synergies with a cable-driven transmission mechanism consisting of two spring-loaded sliders and five V-shaped bars. Specifically, we used fixed synergy weightings to determine the stiffness of the compression springs, and the displacements of sliders were determined by time-varying activation coefficients. The derived transmission system was then used to drive a five-finger robotic hand named SYN hand. We also designed a motion encoder to selectively activate desired fingers, making it possible for two motors to empower a variety of hand postures. Experiments on the prototype demonstrate successful grasp of a wide range of objects in everyday life, and the finger force distribution of SYN hand can approximate that of human hand during six typical tasks. To our best knowledge, this study shows the first attempt to mechanically implement force synergies for finger force modulation in a robotic hand. In comparison to state-of-the-art robotic hands with similar functionality, the proposed hand can distribute humanlike force ratios on the fingers by simple position control, rather than resorting to additional force sensors or complex control strategies. The outcome of this study may provide alternatives for the design of novel anthropomorphic robotic hands, and thus show application prospects in the field of hand prostheses and exoskeletons.
Vertical structures and drivers of marine heatwaves and cold-spells in the Kuroshio Extension region
Authors: Xu Qiang , Liu Kai , Wang Haiyan , Chen Xingrong
Published: April 2024

Marine heatwaves (MHWs) and marine cold-spells (MCSs) are prolonged oceanic extreme temperature events that can severely impact large-scale ecosystems, fisheries, and human activities with consequent socioeconomic impacts. Although some studies have contributed valuable insights into the vertical structure and related mechanisms of MHWs, equivalent research on MCSs remains unclear. Thus, comprehensive and systematic analysis of the vertical structures and related mechanisms of MHWs and MCSs remains area of an active research. In this study, we classified MHWs/MCSs into two types in the Kuroshio Extension region: extended MHWs/MCSs that can extend through more than 70% of the water column and shallow MHWs/MCSs that are restricted from the surface layer to less than 70% of the water column. Analysis revealed that shallow events are characterized by stronger intensity and shorter duration compared with extended events. All shallow events are driven by surface heat flux anomalies, with shortwave radiation (latent heat flux) mostly inducing those in MHWs (MCSs). However, extended MHWs/MCSs are primarily driven by ocean anticyclonic/cyclonic eddies. These findings provide deeper understanding of the statistical characteristics, vertical structures, and physical drivers of MHWs and MCSs.
Seismic Response of a Tall Reinforced Concrete Frame Structure Subjected to both Horizontal and Vertical Strong Motions
Authors: Toma A M , Movila M , Rosca O V , Toma I O
Published: April 2024

The continuous development of urban areas coupled with the ageing of built-stock and the variety of structures built following different design code recommendations may result in different behaviours during seismic events. Hence, reliable information is needed in order to assess the risk of severe damage or collapse during earthquakes. Accurate numerical simulations coupled with analytical models provide essential information on the seismic performance of civil engineering structures. The results obtained from realistic numerical simulations may serve as entries in data-bases designed to train and calibrate early warning systems (EWS). Their continuous development is of paramount importance taking into account their potential to save lives and prevent economic loses in case of a severe seismic event. The paper presents the preliminary results obtained from numerical simulations on the seismic response of a tall reinforced concrete (RC) frame structure subjected to both horizontal and vertical string motions produced by an earthquake. The obtained results, in terms of response spectra in terms of accelerations, may be used for training EWS sensors to identify a seismic event and transmit warning messages at local, regional and even national level.
Comparative analysis of two strengthening solutions for the structural rehabilitation of a historical masonry building
Authors: Taranu G , Olteanu I , Entuc I-S , Colt O-E , Bunea G , Toma I-O
Published: April 2024

The paper presents a comparative analysis based on the Finite Element Method (FEM) for a masonry building located in Iasi, the North-Eastern side of Romania. This specific region is known to be found in a seismic area having a design peak ground acceleration of 0.25g. The building was assessed as being in the 1st seismic risk class, according to the Romanian norms, with a high probability of collapse in case of future earthquakes. Being a historical monument, the structural strengthening solutions are very limited. The study consists of modal and seismic analyses for the masonry structure. A comparison of the advantages and disadvantages of two approaches of structural rehabilitation solutions is done. The structural strengthening solution “A” consists of the addition of reinforced concrete thin wall elements, while the other - called solution “B” - consists of an interior steel profile skeleton mechanically and chemically connected to the adjacent masonry walls.
Case study on reinforced concrete frame structure adaptability
Authors: Olteanu I , Anton C-I , Țăranu G
Published: April 2024

The limited space to build from scratch significantly increased the need to rehabilitate for the re-functionalization of different buildings. The reinforced concrete frame structure is easily adaptable and has several advantages in this direction. When changing the function of a building an evaluation of the existing damages is done as well as a numerical simulation with the new loads. The article presents the case of changing a neighbourhood clinic into a kindergarten. The seismic risk coefficients are computed (R1, R2 and R3) in order to establish the seismic risk class for the existing building and also an evaluation of the damage state. A comparison between the seismic force computed when the building was designed and according to current codes is performed. In order to identify the failure mechanism pushover analysis was performed in both X and Y direction.
Fiber reinforced polymers in pervious concrete - a state of the art review
Authors: Chiriac R D , Kiss Z I
Published: April 2024

Porous concrete, entitled also as permeable or pervious concrete, is a type of concrete that has interconnected voids that allow water and also air to go across it. It is widely used in the construction of pavements, parking lots, and sidewalks, among other applications, because of its ability to reduce stormwater drainage, better quality of the water, and decrease urban heat island effects. The addition of fibers to porous concrete has been the subject of numerous studies in recent years, with researchers examining the effects of diversified types and amounts of fibers on the material’s properties. Fiber reinforcement can enhance the strength, durability, and ductility of porous concrete, making it more suitable for use in structural applications. Polymer fibers, in particular, have shown promise in improving the properties of porous concrete. They can increase the material’s resistance to cracking, improve its flexural strength, and enhance its heat-absorbing property. However, the characteristics of polymer-reinforced porous concrete are not yet fully understood, and more research is needed to determine the optimal types and amounts of fibers for specific applications. Despite the potential benefits of fiber-reinforced porous concrete, there are also some challenges associated with its use. The addition of fibers can increase the material’s cost and complexity of production, and it may also affect its permeability and drainage capacity.

Fiber-reinforced porous concrete represents an exciting area of research and development in the field of civil engineering. While the addition of fibers can enhance the material’s properties, more research is needed to determine the optimal types and amounts of fibers for specific applications. By addressing these challenges and continuing to refine the material’s properties, fiber-reinforced porous concrete has the potential to expand its use in a large spectrum of applications, including structural engineering, transportation infrastructure, and environmental protection.
Enhanced circular dichroism of an X-shaped nanostructure by asymmetric surface plasmon interference
Authors: Abdukerim Abduweli , Abdusattar Haximjan
Published: April 2024

A plasmonic chiral structure, which is a nanostructure composed of noble metals that lacks planar symmetry, demonstrates significant potential for various applications in bio-sensing, optical forces, switching and controlling the photoluminescence, and detecting chiral light. Understanding its fundamental property of circular dichroism (CD) is critical for these applications. Although the surface plasmon resonance (SPR) mode at a specific moment can explain the CD properties of chiral structures, to gain a better understanding of chirality, the mode shape of the SPR on a nanostructure must be analyzed throughout an entire period. Our study proposes an X-shaped nanostructure to investigate the temporal evolution of plasmon resonance in chiral structures. The simulation results demonstrated that our structure exhibited a significant temporal evolution in plasmonic oscillations, providing new insights into the nature of chirality. In addition, we provided a comprehensive theoretical explanation of CD using the Born–Kuhn model. Furthermore, we discovered that the CD in the X-shaped structure was intensified by the asymmetric interference between the structure and underlying gold film substrate.
Design of ultra-compact thin-film lithium niobate edge coupler based on micro–nano structure
Authors: Qin Yan-Yan , Xue Xiao-Mei , Shi Lei , Zhang Xiao-Yang , Zhang Tong
Published: April 2024

High coupling loss due to fiber-to-chip mode mismatch is considered as one of the main hindrances to thin-film lithium niobate (TFLN) devices to replace their bulk counterparts in engineering applications. In this work, we introduce subwavelength micro–nano structure and slot-strip mode coupling to design an efficient and ultra-compact edge coupler to solve the mismatch issue. The total device length is 130 μm, which is only 43% of the lengths of general TFLN edge couplers and even 35% shorter than the shortest one while maintaining low coupling loss (0.47 dB/0.38 dB per facet @1550 nm for TE/TM mode). This work provides a case study for the design of integrated photonic devices on the TFLN platform.