bluuebunny/crossref_metadata_2025 huggingface dataset:
Surface Threat Event Identification for Subway Tunnels Using Multi-classifier Fusion Algorithm Based Optical Fiber DAS System
Authors: He Tao , Zhang Shixiong , Li Hao , Yan Zhijun , Liu Deming , Sun Qizhen
Published: February 2024

Multi-classifier fusion algorithm is proposed to identify surface intrusion events in the subway tunnel. Experimental demonstration verifies that the average recognition rate of 96.1% for four target events is achieved by the proposed scheme.
Optical Fiber Subway Intrusion Monitoring using the entropy of the wavelet packet coefficients and wavelet multi-scale ridge detection
Authors: Lou Minggan , Huang Wenzhu , Li Fang , Zhang Wentao
Published: February 2024

An optical fiber accelerometer array for subway tunnel intrusion monitoring were proposed. By using the entropy of the wavelet packet coefficients and wavelet multi-scale ridge detection, the alarm of drilling rig signal was successfully realized.
Optical Fiber Lateral Stress Sensor Based on Michelson Interference and Optical Vernier Effect
Authors: Li Yujian , Xu Pin , Lyu Weimin , Liu Yifan , Yu Changyuan
Published: February 2024

An ultra-sensitive optical lateral stress sensor with the Optical Vernier effect is designed using polarization-maintaining fiber based on the Michelson interferometer.
High-sensitivity intensity-interrogated temperature sensor based on phase-modulated grating in chalcogenide fiber
Authors: Zhu Chengliang , Wang Lei , Zhao Yong , Li Hongpu
Published: February 2024

A high-sensitivity intensity-interrogated temperature sensor is proposed and numerically demonstrated. The sensor is realized by the optical fiber edge-filter (OFEF) based on the phase-modulated long period fiber grating (PMLPG) in chalcogenide fiber. The obtained sensitivity is ~30 times larger than that of the conventional LPGs in silica fibers.
Human Thyroglobulin detection by Surface-Enhanced Raman Scattering (SERS) optrodes
Authors: Spaziani S. , Quero G. , Managò S. , Zito G. , Terracciano D. , Macchia P. E. , Galeotti F. , Pisco M. , De Luca A.C. , Cusano A.
Published: February 2024

Here, we report a novel biosensor optrode based on a sandwich immunoassay with a self-assembled SERS substrate and functionalized gold nanoparticles, capable of detecting thyroid cancer biomarker, Thyroglobulin, with very high sensitivity.
An Improved Algorithm to Monitor the Phase Difference of Three-Phase Power by Fiber Optic Current Sensor
Authors: Tian Jundong , Yu Aodi , Xia Li
Published: February 2024

An algorithm for monitoring phase difference of three-phase power without using currents demodulated by fiber-optic current sensor is proposed, which monitors the peak-to-peak of the three groups of Faraday phase shift differences to keep stability.
Optical Fibre Based Angle Measurement for Robotic Joints
Authors: Pillai Sivaji , Charrett Thomas O.H. , Kissinger Thomas , Barrington James H. , James Stephen W , Tatam Ralph P.
Published: February 2024

Abstract: A multiplexed array of optical fibre based angle sensors for deployment on multiple joints of a robotic arm is demonstrated. Two optical fibres, each containing an array of fibre segment interferometers, are bonded either side of the neutral axis of a thin, flexible metal tape. Differential measurement of the phases of corresponding interferometers in the two fibres yields an angle measurement with resolution better than 0.001° over a bandwidth of 21 kHz when demodulated using the principles of range resolved interferometry.
Fiber optic borehole strainmeter based on double Fabry-Pérot interferometers with inconsistent cavity lengths
Authors: Li Huicong , Huang Wenzhu , Li Li , Zhang Wentao
Published: February 2024

A fiber optic borehole strainmeter designed by double Fabry-Pérot interferometers with different cavity lengths and different supporting materials is proposed. It has a strain response of 0.098 μm/με and two temperature responses of 0.73 μm/℃ and 0.17 μm/℃, which is expected to achieve a resolution of 12.3 pε/√Hz.
A Novel Localization Algorithm Based on Dual-microphone Fiber Optical Interferometer for Pipeline Leakage Detection
Authors: Wu Yingjie , Bao Tian , Wang Chao , Li Churui , Jia Bo
Published: February 2024

A dual microphone localization algorithm based on Mach-Zehnder-Sagnac interferometer for pipeline leakage is proposed. The experimental results demonstrate that the positioning effect with standard deviation of 5 cm can be achieved.
Temperature and Strain Sensing with a BOTDR: Method for Setting the Calibration Coefficients in the Field
Authors: Lecoeuche Vincent
Published: February 2024

The knowledge of the optical fiber response is a prerequisite for accurate simultaneous temperature and strain sensing. Each installation being unique, we propose a method for tuning the fiber calibration coefficients in the field using a BOTDR.
Time-expanded phase-sensitive OTDR: High-resolution DAS based on dual-comb spectroscopy
Authors: Fernández-Ruiz María R. , Soriano-Amat Miguel , Escobar-Vera Camilo , Martins Hugo F. , Durán Vicente , Martin-Lopez Sonia , Gonzalez-Herraez Miguel
Published: February 2024

A perspective of a novel DAS is offered. By using dual frequency combs (DFC), we attain time-expansion of ΦOTDR traces. Customized performance can be attained by engineering DFC parameters. Results obtained to date are summarized.
Two-component photothermal gas sensor with a pump-probe-alternating technique
Authors: Guo Linhao , Zhao Pengcheng , Jiang Shoulin , Bao Haihong , Gao Shoufei , Wang Yingying , Ho Hoi Lut , Jin Wei
Published: February 2024

We report a high-sensitivity hollow-core fiber photothermal acetylene/methane gas sensor with a reduced pump-probe configuration, which alternately uses two distributed feedback lasers as pump and probe beams via time-division multiplexing.
Precision Measurements with a Code-Division Multiplexing Interrogator on Large Draw Tower Grating Arrays
Authors: Götten M. , Van Roosbroeck J. , Lindner E. , Lochmann S. , Vlekken J.
Published: February 2024

A new interrogator has been developed that relies on the principles of code-division multiplexing (CDM), called the ‘FBGS InfinityScan®’. It can measure the wavelengths of multiple wavelength-division multiplexed (WDM) sections of Draw Tower Gratings (DTG®s) in series. Wavelength precision measurements have been done with this interrogator as a function of the WDM section from an exemplary CDM sensing network. It shows that the position of the WDM section in the fiber does not have a significant impact on the measured precision.
Repeaterless Distributed Acoustic Sensing using Phase-OTDR with All-Optical Amplification for 200 km Sensing Range
Authors: Allousch M. Ali , Crickmore Roger , North Thibault , Marx Benjamin , Hayward Justin , Jostmeier Thorben
Published: February 2024

Distributed Acoustic Sensing (DAS) with increased distance range employing repeaterless all-optical amplification and single-side interrogation schemes is demonstrated. 200 km distributed acoustic sensing range is achieved and signal fading statistics at long ranges are analysed.
Enhancing Label-Free Biochemical Sensing via Graphene Oxide Layer Deposition on Dual Resonance Peak Long Period Gratings
Authors: Dissanayake Kasun P. W. , Ghosh Souvik , Binetti Leonardo , Alwis Lourdes , Azizur Rahman B. M. , Sun Tong , Grattan Kenneth T. V.
Published: February 2024

This research introduces a novel label-free graphene oxide-coated dual-peak long-period grating sensor for measuring protein concentrations. It achieves high sensitivity (22 nm/(g/mL)) and a low limit of detection (0.9 µg/mL), demonstrating extremely high potential for fiber optic biosensor development.
Single-end vibration measurement in fast BOTDA method based on broadband light with fiber mirror reflector
Authors: Ishimaru Takahiro , Wakisaka Yoshifumi , Takahashi Hiroshi , Koshikiya Yusuke
Published: February 2024

We propose a single-end vibration measurement based on the fast BOTDA method by using a fiber mirror reflector. We demonstrate the measurement of 100 Hz and 460 µε simulated vibration over 1050 m.
Distributed Fiber-Optic Sensor as an Acoustic Communication Receiver Array
Authors: Kohno Wataru , Fang Jian , Murakami Shuji , Milione Giovanni , Wang Ting
Published: February 2024

A novel acoustic transmission technique using distributed acoustic sensors is introduced. By choosing better incident angles for smaller fading and employing an 8-channel beamformer, over 10KB data is transmitted at a 6.4kbps data rate.
Seawater temperature sensing probe based on water-cladding elliptical microfiber
Authors: Jin Wa , Liu Xiaoqing , Chen Siwen , Fu Xinghu , Fu Guangwei , Bi Weihong
Published: February 2024

A water-cladding elliptical microfibers sensing probe is proposed for highly sensitive remote seawater temperature measurement, which effectively avoid cross-sensitivity in measurement of seawater temperature and is more suitable for real-world applications.
Interferometric Fiber-Optic Sensor for Electrical Partial Discharge Detection
Authors: Yan Gaocheng , Chen Jiageng , Niu Heng , Qiao Feng , He Zuyuan
Published: February 2024

We propose an interferometric fiber-optic sensor and investigate its ability to measure the partial discharge in electrical applications. Preferable performance can be achieved under system self-noise level of 10
−
6 rad/Hz1 2 and 100 kHz frequency band.
Fiber Bragg Grating for in Operando Temperature Distribution Monitoring in a PEM Water Electrolyser
Authors: Xu Man , Cheng Lun , Toet Peter , Zandi Marie , van Aken Coen , de Groot Arend
Published: February 2024

Hydrogen is expected to play a significant role in the energy transition. Proton Exchange Membrane (PEM) electrolyser is a promising key technology and can be used in different applications. One of the important parameters related to the PEM efficiency is the temperature distribution. The usage of fiber Bragg grating (FBG) sensor array to measure temperature at different locations and flow channels close to the membrane is successfully demonstrated. The application of bend-insensitive fiber enables the routing of a single fiber into the different flow channels. The temperature measured by the FBGs in the flow channels is compared to conventional electrical temperature sensor attached to the PEM housing. While the effect of changes in the cell voltage is clearly detected by the FBGs inside the PEM.
Detecting Physical Impacts by Monitoring State of Polarisation in a Live Fibre-To-The-Home Data-communication Air-Cable
Authors: Bjørnstad Steinar , Ali Jameel , Dreibholz Thomas
Published: February 2024

Heavy wind may tear cables down, damaging infrastructure, triggering outage in data-communication networks. We demonstrate local observations of wind in the access-network, monitoring State of Polarisation in a live Fiber To The Home air-cable.
Rectangular Polymer Fiber Accelerometer for Pantograph Catenary System
Authors: Dash Jitendra Narayan , Yu Yaokang , Cheng Xin , Tam Hwa-Yaw
Published: February 2024

We fabricated a rectangular multicore polymer optical fiber to build an accelerometer to measure pantograph-catenary interaction force. It has a sensitivity of 17.07 pm/g at 40Hz, can withstand 25 g, and operate up to 75°C.
Understanding noise floor behavior in optical correlation-domain reflectometry with acousto-optic modulator
Authors: Yoshida Soshi , Kiyozumi Takaki , Mizuno Yosuke
Published: February 2024

We experimentally reveal that the folding effect of a beat spectrum causes a double-peak noise floor in optical correlation-domain reflectometry with an acousto-optic modulator. This noise could be mitigated by employing larger frequency shifts.
Improved Dual-wavelength Demodulation Technique Based on Priori Information for Fiber Optic Fabry-Perot Ultrasonic Sensors
Authors: Huang Yi , Zhang Lina , Wang Liangjie , Hu Chengyong , Deng Chuanlu , Zhang Xiaobei , Wang Tingyun
Published: February 2024

An improved dual-wavelength demodulation technique is proposed to achieve high-precision demodulation of fiber optic Fabry-Perot ultrasonic sensors over a wide dynamic range. Theoretically, sensors with arbitrary cavity length can be demodulated by the proposed technique.
Dual-channel fiber optic current sensor based on carrier-transposed modulation technique
Authors: Yu Aodi , Tian Jundong , Xia Li
Published: February 2024

A dual-channel fiber optic current sensor based on carrier-transposed modulation technique is proposed and demonstrated. The cross-talk between two channels is tactfully eliminated, which provides an innovative method to multi-channel current measurement without additional expense.
Intensity-modulated hydrostatic level sensor using a hetero-core fiber optic strain sensor
Authors: Yamazaki Hiroshi , Sasaki Hiroyuki , Watanabe Kazuhiro
Published: February 2024

A diaphragm-seal hydrostatic level sensor was proposed for a cost-effective intensity-modulation measurement scheme by hetero-core fiber optics. The proposed sensor was experimentally evaluated with respect to the responsibility to hydrostatic pressure up to 20.0 kPa.
Using Novel Fibre Bragg Grating Based Pressure Sensor for Early Detection of Pipeline Leaks
Authors: Bremner James AA , Fabian Matthias , Scott Richard , Carlton John , Sun Tong , Grattan Kenneth TV , Bustamante Heriberto , McCulloch James , Hill Tim , Tait Simon , Horoshenkov Kirill
Published: February 2024

We present a novel FBG-based pressure sensor for detection of pressure waves associated with pipe leaks. It includes the sensor design concept, sensor calibration in a pilot plant scale rig that mimics a water distribution network and the simulated pipeline leakage tests.
Bending Monitoring of a Vertical Axis Wind Turbine Tower by Means of FBG Strain Sensors
Authors: Van Esbeen Bastien , Manto Valentin , Kinet Damien , Caucheteur Christophe
Published: February 2024

A vertical axis wind turbine tower was equipped with FBG for SHM. The obtained results explain the deduction of three deformation sources and the most sensitive position of sensors along the tower height was determined.
Direct sag measurement over OPPC based on Chirped-Pulse Phase-Sensitive OTDR
Authors: Canudo Jorge , Sevillano Pascual , Iranzo Andrea , Kwik Sacha , Preciado-Garbayo Javier , Subías Jesús
Published: February 2024

Distributed acoustic sensing using CP-ΦOTDR enables a reliable measurement of vibrations in overhead conductors. A real-time frequency analysis of this vibrations enables for monitoring the sag value allowing dynamic capacity setting for improved line efficiency.
Towards weigh-in-motion in asphalt structures by FBGs
Authors: Pradas Javier , Rodríguez Armando , Leandro Daniel , Lopez-Amo Manuel , Bravo Mikel
Published: February 2024

In this contribution, the potential of an array of FBGs for weigh-in-motion and weight distribution in vehicles in a real urban environment is studied.
Optical Fibre Sensors for Radiation Dosimetry: Challenges and Opportunities
Authors: O’Keeffe Sinéad , Martyn Michael , Woulfe Peter , Hanly Jennifer
Published: February 2024

We present our latest advances in optical fibre sensors for radiotherapy dosimetry, with a particular focus on in vivo brachytherapy, and discuss the main challenges and opportunities for their use in improving patient outcomes.
On the Long-term Persistence of Rayleigh Signature of Optical Fibres in Harsh Conditions
Authors: Schenato Luca , Cappelletti Martina , Orsuti Daniele , Galtarossa Andrea , Santagiustina Marco , Cola Simonetta , Palmieri Luca
Published: February 2024

In this paper, we address the persistence of Rayleigh signature in optical sensing fibres installed in harsh environments. The measurements of some fibres installed in rough conditions and analysed with the Spectral Correlation Analysis show that they still preserve their Rayleigh signature more than five years after installation. © 2023 The Author(s)
White-light multi-beam interferometry for resonant fiber optic gyroscope and other applications
Authors: Liu Qingwen , Zhao Shangxiang , Ma Huilian , He Zuyuan
Published: February 2024

White-light multi-beam interferometry technology has been developed for the interrogation of resonant fiber-optic sensors. Three types of implementations and corresponding applications are introduced based on either intensity or phase response of fiber ring resonators.
Improved Closed-Loop Slow-Light Temperature Sensor With Millidegree Resolution for Laser Cooling
Authors: Balliu Enkeleda , Talbot Lauris , Chen Chun Wei , Frey Benjamin , Meehan Bailey , Hawkins Thomas W. , Ballato John , Boilard Tommy , Bernier Martin , Digonnet Michel J. F.
Published: February 2024

For applications such as laser cooling of doped fibers, where it is critical to measure accurately the temperature of a cooled fiber that is very close to room temperature, it is paramount to develop a reliable, very short (mm) fiber temperature sensor with millikelvin resolution and very little drift. We report a second generation of a unique slow-light fiber Bragg grating (FBG) temperature sensor that meets these stringent requirements. Experiments and modeling establish that its temperature response depends only on well-known material constants of the silica FBG and the response of the probe laser’s wavelength controller. The response is independent of the linewidth of the slow-light resonance, hence different FBGs and/or resonances have the exact same response. Examples of measured cooling in optically pumped Yb-doped fibers show that more reliable thermal contact with the cooled fiber is obtained by wrapping the FBG and the cooled fiber.
Polarization-induced nonlocal effects in distributed acoustic sensing and their dependence on the interrogation pulse width
Authors: Burstein Eran , Eyal Avishay
Published: February 2024

We study nonlocal effects in distributed acoustic sensing due to the polarization dependence of the Rayleigh backscattering profile. The dependence of the phenomenon on the interrogating pulse width is characterized theoretically and experimentally.
Development of Low-Cost SDH-BOTDR using Directly Modulated Laser
Authors: Koizumi Kengo , Murai Hitoshi
Published: February 2024

We developed a low-cost self-delayed homodyne BOTDR by employing directly modulated DFB-LD. A 1 km distributed measurement with a 1 m spatial resolution was successfully demonstrated within 1 s by compensating SPM.
Optimization Strain Accuracy for Distributed Sensing based on Optical Frequency Domain Reflectometry
Authors: Chen Yuzhou , Lin Cuofu , Yang Jun , Wang Yuncai , Qin Yuwen
Published: February 2024

The equation is proposed that strain accuracy is inversely proportional to sweep range, signal-to-noise ratios and the cubic of strain spatial resolution. We obtained 6.4με strain accuracy (2σ) with 1mm strain spatial resolution.
Demonstration of the real-time feedback control with the MicroLiDAR
Authors: Hayashi Neisei , Ishii Katsuhiro , Hasegawa Hiroshi , Furukawa Hideaki
Published: February 2024

We demonstrated laser welding with feedback based on a keyhole measured by a MicroLiDAR. Its depth was real-time processed with a 1-ms delay and the weld penetration depth was linear with fluctuations of 200 um.
Bioinspired self-powered optical fiber sensor array for tactile perception
Authors: Zheng Hongyan , Xiong Puxian , Gan Jiulin
Published: February 2024

Inspired by neural tactile sensing system, we innovatively integrate mechanoluminescence material on the endsurface of optical fiber arrays to design a tactile sensor with the merits of high-resolution, low-pressure threshold and self-powering ability.
8-Shaped Birefringent Optical Fiber in Sagnac Interferometer for Low-Pressure Sensing
Authors: Htein Lin , Cui Jingxian , Gunawardena Dinusha Serandi , Cheng Xin , Tam Hwa-Yaw
Published: February 2024

An 8-shaped birefringent optical fiber fabricated by mechanical milling is proposed for low pressure sensing based on the Sagnac interferometric technique. The sensor provides a sensitivity of 441 pm/kPa with an accuracy up to 2 Pa.
Evaluation of Response of Hetero-core Fiber Optic Surface Plasmon Resonance Sensor to Corrosion Process of Aluminum Thin Film by NaOH Solution
Authors: Kang Dowon , Watanabe Kazuhiro , Nishiyama Michiko
Published: February 2024

Using a hetero-core fiber optic sensor deposited with Au/Ta2O5/Al multi-layer, the corrosion process of Aluminum by NaOH solution was detected with transmission light in three different pH solutions, three different thicknesses of Al thin films.
SNR Improvement for Distributed Acoustic Sensing with Strong Environmental Background Interference
Authors: Li Caiyun , Liu Zechao , Zheng Hongkun , Zhuang Yiyang , Zhu Chen , Hu Weiwang , Wang Jianguo , Ma Lingmei , Rao Yun-Jiang
Published: February 2024

A novel method is proposed to correct the distortions induced by phase unwrapping error. The method is further validated in processing the data acquired from a field test performed in ocean environments using a DAS system.
3mm Demodulation of Forward Stimulated Brillouin Scattering by Brillouin Amplification
Authors: Li Tianfu , Ba Dexin , Jiang Taofei , Li Hongwei , Ren Yuli , Chen Chao , Dong Yongkang
Published: February 2024

An efficient scheme for forward stimulated Brillouin scattering by Brillouin amplification is proposed, and a spatial recognition capability of 3mm is achieved in air, which is 2 orders of magnitude higher than the previous reported.
New Applications of Integrated Optics in Quantum Photonics and Machine Learning
Authors: Di Lauro L. , Sciara S. , Aadhi A. , Montaut N. , Alamgir I. , Perron N. , Fischer B. , Dmitriev P. , Yu H. , Mazoukh C. , Chemnitz M. , Little B. E. , Chu S. T. , Moss D. J. , Wang Z. , Morandotti R.
Published: February 2024

We utilize integrated photonic platforms, performing multiple high-speed operations simultaneously in a compact footprint, to demonstrate classical signal processing supported by machine learning, as well as quantum information processing at telecom wavelengths. © 2023 The Author(s)
Temperature measurement and scanning thermal imaging in micro-nano region with near-field optical fiber probe
Authors: Li Shaoying , Chen Na , Liu Zhenmin , Liu Shupeng , Shang Yana , Liu Yong , Chen Zhenyi , Pang Fufei , Wang Tingyun
Published: February 2024

This study proposes an optical scanning thermal imaging method for micro-nanoscale thermal characterization utilizing a near-field fiber optic probe with CdSe quantum dots, validated through in-situ measurement of bond wire temperature distribution.
Recirculating Sagnac-enhanced Photothermal Gas Detection with a Nanofiber as the Absorption cell
Authors: Tan Yanzhen , Zhao Shuangxiang , Jiang Shoulin , Liao Hanyu , Jin Wei
Published: February 2024

We present a recirculating Sagnac-enhanced nanofiber photothermal sensor for trace gas detection. Experiments with a resonating cavity of finesse 34 demonstrated a detection limit of 74 ppb acetylene, ~6 times enhancement over the non-resonating sensor.
Digital simulation of underwater turbulence channel based on the Monte Carlo method
Authors: Pang Diyue , Tong Shoufeng , Wen Ke , Wang Tong , Lin Peng , Xu Li , Wang Bowen , Yu Xiaonan
Published: February 2024

Our method, using Nikishov’s spectral model, assesses weak turbulence disturbance in underwater wireless optical communication (UWOC) systems. It computes scintillation indices and generates turbulence coefficients. It simulates optical signals at the detector, determining the bit error rate (BER) via decision demodulation. Analysis reveals that the slope of the relationship curve between the receiving antenna aperture and the scintillation index is maximized to 0.0377 when the receiving antenna aperture is 18 mm. For an average BER of 1E-6, required average signal-to-noise ratios (SNRs) are 9.84, 10.21 and 13.01 dB. Comparisons reveal <4% relative error and 0.071% root-mean-square error in average BER vs. average SNR curves, validating time-domain semi-physical UWOC simulations.
Unwrapping Non-Locality in the Image Transmission Through Turbid Media
Authors: Kazemzadeh Mohammadrahim , Collard Liam , Piscopo Linda , Pisano Filippo , Ciraci Cristian , De Vittorio Massimo , Pisanello Ferruccio
Published: February 2024

Achieving high-fidelity image transmission through turbid media is a significant challenge facing both the AI and photonic/optical communities. While this capability holds promise for a variety of applications, including data transfer, neural endoscopy, and multi-mode optical fiber-based imaging, conventional deep learning methods struggle to capture the nuances of light propagation, leading to weak generalization and limited reconstruction performance.
To address this limitation, we investigated the non-locality present in the reconstructed images and discovered that conventional deep learning methods rely on specific features extracted from the training dataset rather than meticulously reconstructing each pixel. This suggests that they fail to effectively capture long-range dependencies between pixels, which are crucial for accurate image reconstruction.
Inspired by the physics of light propagation in turbid media, we developed a global attention mechanism to approach this problem from a broader perspective. Our network harnesses information redundancy generated by peculiar non-local features across the input and output fiber facets. This mechanism enables a two-order-of-magnitude performance boost and high fidelity to the data context, ensuring accurate representation of intricate details in a pixel-to-pixel reconstruction rather than mere loss minimization.
Optical magnetic field enhancement using ultrafast azimuthally polarized laser beams and tailored metallic nanoantennas
Authors: Martín-Hernández Rodrigo , Grünewald Lorenz , Sánchez-Tejerina Luis , Plaja Luis , Conejero Jarque Enrique , Hernández-García Carlos , Mai Sebastian
Published: February 2024

Structured light provides unique opportunities to spatially tailor the electromagnetic field of laser beams. These include the possibility of a sub-wavelength spatial separation of their electric and magnetic fields, which would allow isolating interactions of matter with pure magnetic (or electric) fields. This could be particularly interesting in molecular spectroscopy, as excitations due to electric and—usually very weak—magnetic transition dipole moments can be disentangled. In this work, we show that the use of tailored metallic nanoantennas drastically enhances the strength of the longitudinal magnetic field carried by an ultrafast azimuthally polarized beam (by a factor of ∼65), which is spatially separated from the electric field by the beam’s symmetry. Such enhancement is due to favorable phase-matching of the magnetic field induced by the electric current loops created in the antennas. Our particle-in-cell simulation results demonstrate that the interactions of moderately intense (∼1011  W/cm2) and ultrafast azimuthally polarized laser beams with conical, parabolic, Gaussian, or logarithmic metallic nanoantennas provide spatially isolated magnetic field pulses of several tens of Tesla.
Knowledge and attitudes of antenatal mothers towards intimate partner violence in the Gambia: A cross-sectional study
Authors: Jatta Joseph W. , Ouedraogo Jean Claude Romaric Pingdwinde
Published: February 2024

Intimate partner violence is a severe public health and human rights issue that 1 in 3 women experience in their lifetime. A woman’s knowledge and attitudes towards intimate partner violence might influence her experience of violence from an intimate partner. This study aimed at analysing the knowledge and attitudes of antenatal mothers towards intimate partner violence. This study employed a descriptive cross-sectional technique. Pregnant women seeking antenatal care were selected from 6 public healthcare facilities in the Gambian Upper River Region (URR). We used the single proportion formula to calculate the sample size, which was 373 women. Data were entered, cleaned and analysed using SPSS version 21.Majority of the participants had good knowledge about IPV (77%). The most common intimate partner violence known to the women was denial of money to hurt her (80.2%). Only 58% of the women knew that a male partner’s insistence on knowing their whereabouts at all times and expecting them to seek permission before accessing healthcare is a form of violence. Eighty-seven per centof the participants had a negative attitude towards IPV (i.e., they were not precisely against the stated forms of violence perpetrated by their partners). When asked about what would warrant them to leave their partners, 67% claimed they would never leave their partners despite facing violence. According to 36% of the respondents, women stay in abusive marriages because of their children.Despite the relatively high knowledge of pregnant women on IPV, their attitudes tell a different story, which is: acceptance of violent behaviours from their partners. More work needs to be done to sensitise women on their rights not to be violated and engage the whole society in changing the social norms unfavourable to them.
Lived experiences of women during induction of labour at a tertiary hospital in Ghana: A qualitative study
Authors: Atobrah-Apraku Kenneth , Newman Grace T. , Opuni-Frimpong Yaw , Seffah Joseph D. , Adu-Bonsaffoh Kwame
Published: February 2024

Induction of labour (IOL) has become a major and vital maternal health intervention to facilitate childbirth and minimize the rising caesarean section rates globally. However, there is limited information to facilitate appropriate client counselling, birth preparedness and informed decision making although the procedure has inherent tendency for adverse maternal/perinatal outcomes. Given the need for optimal client education and shared decision making in maternal health, this study explored women’s knowledge and their lived experiences of IOL. This qualitative study used in-depth interviews, conducted at the largest teaching hospital in Ghana. Purposive sampling was used to recruit the study participants. Data analysis was performed based on thematic content using inductive framework synthesis. We included 17 women who had undergone IOL, delivered and discharged. Most participants(52.9%) were ≥30 years old, married(88.2%), and 41.1% had no previous childbirth experience. The main indications of IOL were postdate(47%), pre-eclampsia(29%) and gestational diabetes mellitus(11.8%). Data synthesis resulted in three broad themes: women’s knowledge on IOL, women’s experiences of care and women’s difficult experiences including coping mechanisms. We determined mixed responses concerning the themes explored: adequate versus inadequate knowledge; positive versus negative experiences of care and satisfaction. Nearly all women mentioned vaginal examination as their most difficult experience due to severe pain, extreme discomfort, and being psychologically traumatic. The main coping strategy the women developed to navigate the traumatic vaginal examination was by “psyching” themselves. Our study indicates women encounter significant negative and positive experiences during IOL and childbirth in Ghana with vaginal examination cited as the most painful experience. Appropriate antenatal counselling, women empowerment and pre-labour education on childbirth processes and expectations are recommended to enhance birth preparedness and complication awareness. Health system improvement and regular refreshers courses for health workers are urgently required to promote positive women’s experiences of care during labour induction and childbirth.
Clustering of home delivery in Bangladesh and its predictors: Evidence from the linked household and health facility level survey data
Authors: Fatima Kaniz , Khanam Shimlin Jahan , Rahman Md Mostafizur , Kabir Md Iqbal , Khan Md Nuruzzaman
Published: February 2024

Around half of births in Bangladesh occur at home without skilled birth personnel. This study aims to identify the geographical hot spots and cold spots of home delivery in Bangladesh and associated factors. We analyzed data from the 2017/2018 Bangladesh Demographic and Health Survey and the 2017 Bangladesh Health Facility Survey. The outcome variable was home delivery without skilled personnel supervision (yes, no). Explanatory variables included individual, household, community, and healthcare facility level factors. Moran’s I was used to determine hot spots (geographic locations with notably high rates of home delivery) and cold spots (geographic areas exhibiting significantly low rates of home delivery) of home delivery. Geographically weighted regression models were used to identify cluster-specific predictors of home delivery. The prevalence of without skilled personnel supervised home delivery was 53.18%. Hot spots of non-supervised and unskilled supervised home delivery were primarily located in Dhaka, Khulna, Rajshahi, and Rangpur divisions. Cold spots of home delivery were mainly located in Mymensingh and Sylhet divisions. Predictors of higher home births in hot spot areas included women’s illiteracy, lack of formal job engagement, higher number of children ever born, partner’s agriculture occupation, higher community-level illiteracy, and larger distance to the nearest healthcare facility from women’s homes. The study findings suggest home delivery is prevalent in Bangladesh. Awareness-building programs should emphasize the importance of skilled and supervised institutional deliveries, particularly among the poor and disadvantaged groups.
Earthworms and plants can decrease soil greenhouse gas emissions by modulating soil moisture fluctuations and soil macroporosity in a mesocosm experiment
Authors: Ganault Pierre , Nahmani Johanne , Capowiez Yvan , Fromin Nathalie , Shihan Ammar , Bertrand Isabelle , Buatois Bruno , Milcu Alexandru
Published: February 2024

Earthworms can stimulate microbial activity and hence greenhouse gas (GHG) emissions from soils. However, the extent of this effect in the presence of plants and soil moisture fluctuations, which are influenced by earthworm burrowing activity, remains uncertain. Here, we report the effects of earthworms (without, anecic, endogeic, both) and plants (with, without) on GHG (CO2, N2O) emissions in a 3-month greenhouse mesocosm experiment simulating a simplified agricultural context. The mesocosms allowed for water drainage at the bottom to account for the earthworm engineering effect on water flow during two drying-wetting cycles. N2O cumulative emissions were 34.6% and 44.8% lower when both earthworm species and only endogeic species were present, respectively, and 19.8% lower in the presence of plants. The presence of the endogeic species alone or in combination with the anecic species slightly reduced CO2 emissions by 5.9% and 11.4%, respectively, and the presence of plants increased emissions by 6%. Earthworms, plants and soil water content interactively affected weekly N2O emissions, an effect controlled by increased soil dryness due to drainage via earthworm burrows and mesocosm evapotranspiration. Soil macroporosity (measured by X-ray tomography) was affected by earthworm species-specific burrowing activity. Both GHG emissions decreased with topsoil macropore volume, presumably due to reduced moisture and microbial activity. N2O emissions decreased with macropore volume in the deepest layer, likely due to the presence of fewer anaerobic microsites. Our results indicate that, under experimental conditions allowing for plant and earthworm engineering effects on soil moisture, earthworms do not increase GHG emissions, and endogeic earthworms may even reduce N2O emissions.
Go with the flow: Impacts of high and low flow conditions on freshwater mussel assemblages and distribution
Authors: Cushway Kiara C. , Harris Aubrey E. , Piercy Candice D. , Mitchell Zachary A. , Schwalb Astrid N.
Published: February 2024

Understanding the drivers of distribution and assemblage composition of aquatic organisms is an important aspect of management and conservation, especially in freshwater systems that are inordinately facing increasing anthropogenic pressures and decreasing biodiversity. For stream organisms, habitat conditions during high flows may be impossible to measure in the field, but can be an important factor for their distribution, especially for less mobile organisms like freshwater mussels. Hence, the objective of this study was to use a two dimensional HEC-RAS model to simulate hydraulic conditions during high and baseline flows (flows approx. 10–600 x and 0.7 x median daily flows respectively) in a 20 km segment in the San Saba River, Texas in combination with existing mussel survey data from 200 sites (collected every 100m) to 1) examine whether hydraulic conditions differed between areas of increased mussel richness and diversity (referred to as hotspots) and other sites, and 2) understand how well site occupancy and species abundance could be explained by hydraulic conditions occurring under different flow conditions. The results showed that richness and diversity hotspots occurred in deeper areas with lower shear stress, stream power, and Froude number during both high and low flows. Occupancy could be predicted with 67–79% accuracy at the site scale and 60–70% accuracy at the mesohabitat scale (∼20 to 1200 m long). In addition, hydraulic conditions across flow scenarios explained up to 55% of variation in species abundances, but predictions were less successful for species often observed to occupy micro-scale flow refuges such as bedrock crevices. The results indicate that pools may serve as important refuge for all species during both high and low flow events, which may be relatively unique to bedrock-dominated systems. Understanding hydraulic conditions that occur at extreme flows such as these is important given that the frequency and magnitude of such events are increasing due to climate change.
Comparison of ROX, HROX, and delta-HR indices to predict successful weaning from high-flow oxygen therapy in hospitalized patients with COVID-19 pneumonia
Authors: Ruchiwit Pitchayapa , Madua Jaturong , Saiphoklang Narongkorn
Published: February 2024

Background

High-flow nasal cannula (HFNC) therapy is commonly used to treat acute respiratory failure in patients with COVID-19 pneumonia. However, predictors of successful weaning from HFNC in these patients has not been investigated.

Objective

To assess predictors of successful separation from HFNC in patients with COVID-19 pneumonia.

Methods

We conducted a retrospective cohort study at a university hospital in Thailand. Patients with COVID-19 pneumonia requiring HFNC therapy between April 2020 and June 2022 were included. ROX index was defined as the ratio of oxygen saturation (SpO2) / fraction of inspired oxygen (FiO2) to respiratory rate. Heart-ROX (HROX) index was defined as ROX multiplied by heart rate (HR) improvement. HR improvement (delta-HR) was defined as a percentage of the difference between the baseline HR and the morning HR at HFNC weaning day 1 divided by the baseline HR. Weaning success was defined as ability to sustain spontaneous breathing after separation from HFNC without any invasive or non-invasive ventilatory support for ≥48 hours or death.

Results

A total of 164 patients (54% male) were included. Mean age was 61.1±16.1 years. Baseline SpO2/FiO2 was 265.3±110.8. HFNC weaning success was 77.4%. The best cut-off value of ROX index to predict HFNC weaning success was 7.88 with 100% sensitivity, 97.3% specificity, and area under the ROC curve (AUC) of 0.98 (95% CI: 0.937–1.000, p<0.001). The best cut-off value of delta-HR 3.7 with 88.2% sensitivity, 75.7% specificity, and AUC of 0.83 (95% CI: 0.748–0.919, p<0.001). The best cut-off value of HROX index was 59.2 with 88.2% sensitivity, 81.1% specificity, and AUC of 0.89, (95% CI: 0.835–0.953, p<0.001).

Conclusions

The ROX index has the highest accuracy for predicting successful weaning off HFNC treatment in patients with COVID-19 pneumonia. While HROX and delta-HR indices can serve as alternative tools, it is recommended to verify these indices and determine the optimal cut-off value for determining separation from HFNC therapy through a large prospective cohort study.

Trial registration

Clinicaltrials.in.th number: TCTR20221108004.
Numerical study on flow and heat transfer characteristics of rectangular mini-channel of interpolated double S turbulators
Authors: Xi Yinhang , Meng Fanmao
Published: February 2024

In this study, we propose a new type of small-channel plug-in, the double S turbulators, for passive heat transfer enhancement to improve the flow and heat transfer performance of the fluid in the channel. In the range of Reynolds number 254.51~2545.09, under constant wall temperature heating conditions, the effects of interpolated double S turbulators with different long axial radii (1mm, 1.5mm, 2mm) on the average Nusselt number, pressure drop, total thermal resistance and field synergy number in the rectangular mini-channel were studied. The simulation results show that compared with the smooth rectangular mini-channel, after interpolating double S turbulators with different long axial radii (1mm, 1.5mm, 2mm), the average Nusselt number increased by 81.74%~101.74%, 71.29%~94.06%, 67.16%~88.48%, the total thermal resistance decreased by 45.1%~50.72%, 41.72%~48.74%, 40.28%~47.2%, and the number of field synergies increased by 85.58%~111.65%, 74.1%~102.6%, 69.64%~96.12%. At present, there are few studies on the boundary condition of constant wall temperature, and this paper supplements the research on this aspect. At the same time, the heat transfer performance of the rectangular mini-channel of the interpolated double S turbulators is stronger than that of the ordinary smooth rectangular mini-channel, which not only provides a new idea for the manufacture of micro heat dissipation equipment, but also improves the heat transfer performance of micro heat dissipation equipment and improves its work efficiency. According to the simulation data, the prediction formula of average Nusselt number and pressure drop was established by nonlinear regression method, which can be used to predict the flow and heat transfer characteristics of the rectangular mini-channel of the interpolated double S turbulators.
Unpacking the optimistic mindset of business students towards entrepreneurship
Authors: Ma Haoran , Khan Ali Junaid , Fayyaz Sana , Hameed Waseem Ul , Ullah Habib
Published: February 2024

Entrepreneurial ventures are established in large numbers in China. The success rate of these entrepreneurial ventures is lower than that of new startups. Mismanagement and a lack of creative skills among entrepreneurs are cited as reasons for entrepreneurial failure in China. The current study investigates the impact of entrepreneurial networking and new venture intention on entrepreneurial success in China, with psychological capital and entrepreneurial optimism serving as moderators. 483 responses were collected from business students in China for data analysis. The findings of the study reveal that the impact of entrepreneurial networking and new venture intention on entrepreneurial success in China, with the moderating role of psychological capital and entrepreneurial optimism, is significant. The theoretical framework of this research has novelty as it introduces new moderating relationships of psychological capital and entrepreneurial optimism in the model of entrepreneurial success. Practically, this study has revealed that entrepreneurial success can be achieved with entrepreneurial networking, entrepreneurial optimism, psychological capital, and new venture intention. The directions of this research point out additional gaps in the literature that scholars should discuss in subsequent studies.
Chemo-profiling of Purpureocillium lilacinum and Paecilomyces variotii isolates using GC-MS analysis, and evaluation of their metabolites against M. incognita
Authors: Patidar Prashant , Prasad Lakshman , Sagar Sushma , Sirohi Anil , Saharan Mahender Singh , Dhillon Mukesh Kumar , Singh Vaibhav Kumar , Bag Tusar Kanti
Published: February 2024

Nematophagous fungi are the best alternatives to chemical nematicides for managing nematodes considering environmental health. In the current study, activity of metabolites from ten isolates of Purpureocillium lilacinum (Thom) Luangsa-ard (Hypocreales: Ophiocordycipitaceae) and two isolates of Paecilomyces variotii Bainier (Eurotiales: Trichocomaceae), were examined to inhibit the hatching of Meloidogyne incognita (Kofoid & White) Chitwood (Tylenchida: Heteroderidae) eggs. At 100%, 50%, and 25% concentrations, respectively, the culture filtrate of the isolate P. lilacinum 6887 prevented 97.55%, 90.52%, and 62.97% of egg hatching. Out of all the isolates, Pl 6887, Pl 6553, and Pl 2362 showed the greatest results in the hatching inhibition experiment.Gas chromatography-mass spectrometry (GC-MS) analysis revealed a variety of nematicidal compounds from different isolates. A total of seven nematicidal compounds, including four very potent nematicidal fatty acids were found in the isolate Pl 6553. Secondary metabolites of the same isolate possess the highest M. incognita juvenile mortality, i.e., 43.33% and 92% after 48 hrs of treatment at 100 and 200 ppm concentrations, respectively. Significant difference was observed in juvenile mortality percentage among the isolate having highest and lowest nematicidal compounds. Nematicidal fatty acids like myristic and lauric acid were found for the first time in P. lilacinum. Multiple vacuole-like droplets were found inside the unhatched eggs inoculated with the culture filtrate of isolate Pl 6887, and also in the juveniles that perished in the ethyl acetate extract of isolate Pl 6553.
Ultrasonographic assessment of abnormal fetal growth related to uteroplacental-fetal biometrics and Doppler (U-AID) indices: Protocol for multicenter retrospective cohort study trial
Authors: Choi Eun-Saem , Lee Hwasun , Lee Se Jin , Jung Young Mi , Kim Ho Yeon , Lee Seung Mi , Lee Kyung A. , Seol Hyun-Joo , Ko Hyun Sun , Na Sung Hun , Kwak Dong Wook , Hwang Han-Sung , Choi Sooran , Hong Soon-Cheol , Won Hye-Sung , Kim Suk Young , Kim Hai-Joong , Ahn Ki Hoon
Published: February 2024

Fetal growth restriction (FGR) is one of the leading causes of perinatal morbidity and mortality. Many studies have reported an association between FGR and fetal Doppler indices focusing on umbilical artery (UA), middle cerebral artery (MCA), and ductus venosus (DV). The uteroplacental-fetal circulation which affects the fetal growth consists of not only UA, MCA, and DV, but also umbilical vein (UV), placenta and uterus itself. Nevertheless, there is a paucity of large-scale cohort studies that have assessed the association between UV, uterine wall, and placental thickness with perinatal outcomes in FGR, in conjunction with all components of the uteroplacental-fetal circulation. Therefore, this multicenter study will evaluate the association among UV absolute flow, placental thickness, and uterine wall thickness and adverse perinatal outcome in FGR fetuses. This multicenter retrospective cohort study will include singleton pregnant women who undergo at least one routine fetal ultrasound scan during routine antepartum care. Pregnant women with fetuses having structural or chromosomal abnormalities will be excluded. The U-AID indices (UtA, UA, MCA, and UV flow, placental and uterine wall thickness, and estimated fetal body weight) will be measured during each trimester of pregnancy. The study population will be divided into two groups: (1) FGR group (pregnant women with FGR fetuses) and (2) control group (those with normal growth fetus). We will assess the association between U-AID indices and adverse perinatal outcomes in the FGR group and the difference in U-AID indices between the two groups.