bluuebunny/crossref_metadata_2025 huggingface dataset:
Three-dimensional CFD model and aerodynamic analysis of dragonfly’s corrugated wing during gliding
Authors: Xu Minghao , Xia Wei , Zhang Xin , Hu Shuling
Published: November 2024

The aerodynamic performance of micro air vehicles (MAVs) in low-speed flight would be improved by mimicking the dragonfly’s wing with corrugated airfoil. Research on two-dimensional corrugated airfoils has revealed that the local vortex in the corrugated structure increases the flow speed and the lift-to-drag ratio in low Reynolds numbers. However, studies seldom focus on the effects of three-dimensional corrugated structures on aerodynamics. In this paper, the mechanism of high aerodynamic performance in a dragonfly’s wing is studied considering a three-dimensional corrugated structure. The high-fidelity dragonfly forewing model is established through reverse engineering. The computational fluid dynamics (CFD) simulation is performed for the gliding corrugated wing with angles of attack (AOA) of 0°-24° under three Reynolds numbers. The flow characteristics of corrugated wings and the aerodynamic gain from it are analyzed through the simulated streamlines and pressure contours, as well as the comparison between the corrugated wing, flat wing, and flat plate. The results show that the aerodynamic characteristics of corrugated wings are generally superior. Although the introduction of the corrugated structure increases some drag, it brings a higher lift and lift-to-drag ratio than the flat wings.
Research on assisted recovery algorithm of stall state based on signal guidance
Authors: Zhang Qi , Gu Bo , He Tai , Fang Zili
Published: November 2024

Given the lack of quantitative guidance in the current stall recovery process, which leads to the pilot’s misoperation or untimely recovery, referring to the energy control theory of complex state recovery, a stall state-assisted recovery algorithm based on pitch angle, engine thrust, and roll angle signal guidance was determined. The structure pilot model and the kinematics simulation model of aircraft at a high angle of attack were established. The effectiveness of the algorithm has been verified by simulation analysis. The man-machine closed-loop simulation analysis results show that the algorithm can guide the pilot in effectively recovering from stall conditions under different stall scenarios and engine failure conditions.
Research on optimization of flatness evaluation method for antenna array of a radar vehicle
Authors: Pan Yunping , Yang Yirao
Published: November 2024

Radar vehicles play an important role in providing radar services in the aviation field. The flatness of the antenna array is one of the key factors in ensuring the detection accuracy of radar vehicles for airborne targets. In this paper, the mechanical structure of a new type of radar antenna truck is designed, the stress analysis under various working conditions is carried out, the mechanical performance of the whole vehicle is checked, and the evaluation method of the flatness of the antenna array is discussed. Using ANSYS to carry out static finite element analysis and using the deformation results of each element node in ANSYS, the evaluation method based on the multiple regression function is applied to the calculation scheme of antenna array flatness. The final results show that the safety factor of the radar vehicle structure can reach more than 1.75 under extreme working conditions and more than 2.0 under other working conditions. It can work safely. Through the optimization of the shape evaluation method, the accuracy of the final shape calculation result is less than 10mm. The precision of shape error processing is improved.
Research on the meteorological data transmission system of civil aircraft based on BeiDou satellite
Authors: Gao Yijia , Zhang Zhan , Wang Jue , Li Tieshuai , Chen Jia
Published: November 2024

With the official opening of the Beidou-3 global satellite navigation system, Beidou has entered a new era of global services, extending its service area to the whole world. With the advantages of sufficient data volume and high data security, the BeiDou-3 short message satellite communication system can provide global communication services for airlines, realize two-way data transmission between air and land, and effectively reduce the operating costs of airline companies. Aiming at the demand for low-cost civil aircraft weather data transmission proposed by domestic and foreign airline companies, the current development of civil aviation weather information transmission and the current application status of BeiDou in civil aviation were studied, and the BeiDou satellite-based civil aircraft weather data transmission system was designed. The system architecture, detailed functions and data transmission workflow were analyzed, and the message coding structure was designed using bit-based coding technology. Finally, the feasibility of the scheme is verified through the data demand analysis of weather news and the onboard flight test on a domestic aircraft. The results show that t-he BeiDou short message function has the ability to realize the weather data transmission of a civilian aircraft.
Experimental research of helicopter blade load in flight based on optical sensing
Authors: Geng Lisong , Wang Zefeng , Zhang Honglin , Yang Qianqian
Published: November 2024

The actual flight measurement of blade load is an extremely important part of the new helicopter. In order to solve the problems existing in the traditional electrical measurement method, such as weak anti-interference ability, short life, and large added mass, a flight measurement method of blade load based on optical sensing is proposed. Firstly, the strain mode distribution law is obtained by calculating the dynamic response of the real blade. The optimal layout of the optical fiber measurement points is determined. Through theoretical analysis of strain transferring and experimental verification, a highly reliable fusion scheme of blade and fiber is designed to meet the flight requirements. Based on the power line carrier technology, the optical sensing test system for helicopter flight test is developed. The flight test of blade load is completed successfully. The results of optical fiber measurement are consistent with the results of traditional electrical measurement, which indicates that the optical sensing technology has good applicability in the measurement of helicopter blade load. At the same time, it has been proved that the optical measurement system set is reliable and durable. It is of great significance for the leap from electric measurement to optical measurement.
Uniaxial tensile mechanical properties of NEPE propellant under wide temperature and wide strain rate
Authors: Liu Fan , Qiang Hongfu , Wang Xueren , Wang Zhejun , Lu Chuanjun
Published: November 2024

In order to gain insight into the mechanical properties of the NEPE propellant under a range of temperature and strain rate conditions, the uniaxial tensile mechanical property test of NEPE propellant with a wide temperature range of −40°C-70°C and a wide strain rate range of 0.0012s−1-1s−1 has been carried out based on the in-situ testing device of solid propellant microfabrication under complex working conditions and the supporting high and low temperature integrated machine. Additionally, the morphology of the solid particles of the propellant was observed and analyzed during stretching using the microscope equipment provided by the stretching machine. The results show that it has been demonstrated that both temperature and strain rate exert a more pronounced influence on the mechanical properties of propellants; at low temperatures, it has been demonstrated that the stress-strain curve of the propellant exhibits a more pronounced inflection point as the strain rate increases; the maximum tensile strength of the propellant demonstrates a gradual increase with a reduction in temperature and an increase in strain rate. Furthermore, a linear double logarithmic relationship is observed with the strain rate. In contrast, the maximum elongation exhibits no discernible pattern of change with temperature and strain rate; when observed during stretching, it was found that the main forms of propellant damage destruction at low temperatures were dehumidification between the particles and the matrix and particle rupture.
Torque distribution of distributed drive electric vehicle based on efficiency map of drive system
Authors: Ren Weichen , Li Yanfeng
Published: November 2024

In order to optimize the system efficiency of distributed drive electric vehicles, based on the MAP of the efficiency of the drive motor system, the objective function of the optimal efficiency is established, and the problem of the no-load loss of the drive motor is considered. A torque distribution control strategy method considering the no-load loss of the motor is proposed. Then, AVL CRUISE and Simulink are used to establish a joint simulation platform, and a comparative simulation test analysis is carried out under ECE conditions. The simulation results show that the torque distribution strategy considering the loss makes the distributed drive motor work in a relatively high efficiency range. Compared with the torque distribution strategy without considering the loss, the power consumption is reduced by 3.4%, which effectively improves the vehicle economy. The research results can provide a reference for system efficiency optimization of distributed drive electric vehicles.
A star identification algorithm based on 1D Conv Neural Network
Authors: Zhong Yang , Wang Hao
Published: November 2024

A novel star identification algorithm based on 1D-CNN for celestial navigation is introduced. This approach constructs a distinctive star pattern using radial and angular separations and cyclic angles. Several tests have been conducted on simulated star images, demonstrating the proposed algorithm’s superior performance over conventional algorithms and high resilience to three error types, including spurious stars, positional deviations, and magnitude uncertainties.
Light source deployment study based on downhole visible light communication system
Authors: Haodong Wang , Lincong Zhang
Published: November 2024

With the wide application of visible light communication system, downhole visible light communication system is the best choice for unmanned underground mining in the future. However, there is a lack of research on the deployment of the light source part of the underground visible light communication system. For this reason, this paper proposes a deployment scheme for the light source part of the underground visible light communication system based on the actual operation of underground mining work. Firstly, this paper analyzes the underground visible light communication system model and channel transmission model in detail, and gives the transmission principle model; secondly, it models and analyzes the Light Emitting Diode(LED) at the transmitting end and the Photo-Diode(PD) at the receiving end, and based on the principle model, proposes the channel transmission model in the case of line-of-sight (LOS) and non-line-of-sight (NLOS), and puts forward a scheme to ensure the transmission reliability based on these models. Finally, this paper performs lighting simulation for the proposed scheme. The results show that the light source deployment scheme can meet the reliability requirements of downhole visible light communication systems. The research in this paper provides an important reference for the future deployment of light sources for downhole visible light communication systems.
Effect of electron scattering of microchannel plates on the resolution and halo size of UV image intensifier
Authors: Jing Maoheng , Wang Zhiming , Li Chun , Zhong Meishan , Zhu Shideng , Ma Jian , Zhang Weiyun , Wei Jie , Liu Shengrong
Published: November 2024

Aiming at the problem that the current theoretical model for calculating the resolution of UV(ultraviolet) low-light level image intensifier is not perfect enough to give the optimization conditions directly, the effects of parameters such as the thickness of anti-ion feedback film, MCP(microchannel plate) bevel angle, the depth of the rear electrode and the length-diameter ratio of the channel plate on the photoelectron transport characteristics of UV low-light level image intensifier are analyzed through systematic theoretical research. Experimental results show that optimizing these parameters can significantly improve the performance of the low-light image intensifier. Specifically, when the thickness of the anti-ion feedback film is 4nm, the bevel angle is 8°, the length-diameter ratio is 50, and the back-end electrode is deepened to 10μm, the theoretical image quality of the UV low-light image intensifier reaches a better level. This study has theoretical guidance significance for the development of high-resolution ultraviolet image intensifiers in the field of optoelectronic imaging, and also plays a key role in improving angular resolution in the application of sun blind ultraviolet warning.
Acpro: fusion of embedded ambient light sensor and image sensor for visible light positioning
Authors: Liu Xiangyu , Qi Guangxin , Zhang Junqi , Guo Lei
Published: November 2024

With the increasing demand for indoor positioning, visible light positioning (VLP) systems have become an optics technologies research hotspot due to their high accuracy and avoidance of electromagnetic interference. However, current photodiode (PD)-based and image sensor (IS)-based VLP systems still suffer from high costs at the receiver, and the problem of the trade-off between field of view (FoV) and positioning accuracy. Therefore, we propose a smartphone-based low-cost, and high-precision VLP system, Acpro. The system combines the smartphone’s embedded ambient light sensor and IS as the receiver for the positioning. First, for the low sampling rate of the ambient light sensor, we use the frequency aliasing characteristic to identify the LED’s beacon through the dynamic undersampling principle. Then, to increase the FoV and positioning accuracy, we use the standard distance information corrected by the IS to improve the noise distance calculated by the ambient light sensor. Further, the corrected distance information is used for positioning. Extensive results show that our system can achieve sub-meter positioning accuracy.
Artificial Intelligence-Based Scanner to Locate Flow Anomalies in Water Transmission and Distribution Networks
Authors: Davis Nicholas Arthur , Ardi Sankayya Shetty Divakara , Baskaran Geetha , Hamed Al Adwani Ahmed , Ivy Pascual Lizette
Published: November 2024

The Water Transmission and Distribution sector in Oman is confronted with various challenges, such as flow loss during transportation, negative pressure accumulation, and conflicts in billing consumption in the Water Transmission and Distribution Network(WTDN). To address these and resolve the challenges, a research team, consisting of the authors of this paper, has proposed a wireless flow scanner specifically planned for this purpose. Currently, the proposed cutting-edge wireless AI Water Flow Scanner is undergoing development and finally, be tested in a 540 m total length pilot piping network constructed as 9 parallel pipes with three pipe diameters. The AI Water Flow Scanner will help in locating and quantifying the flow transportation losses, automated pressure balancing, and automated mass flow balancing in the pilot piping network. The proposed AI Water Flow Scanner will receive flow properties like flow pressure, velocity, and discharge through wireless pressure and flow sensors installed in, thirty-six strategic points within the pilot piping network. A deep Learning Algorithm will be developed exclusively to analyze the flow data across the pilot piping network. The analyzed results then be simulated to provide the pressure and velocity distribution across the pilot piping network that will be interpreted to accurately locate the flow transportation losses, imbalance in pressure, and flow across the pilot piping network. Once fully developed and tested, the AI Water Flow Scanner will be expected to offer an efficient and accurate method of locating leaks. In this paper, a network of three parallel pipelines with three different diameters is designed in Pipe Flow Expert, an open-access flow simulation software, analyzed at different flow conditions to understand the flow behavior through the network. The outcome of this simulation is found well aligned with the real-time flaws. A fully developed AI Flow Scanner would help greatly in resolving the current issues in the Water Transmission and Distribution Network of Oman.
IoT-Enabled Street Dustbin Monitoring System Based on Machine Learning
Authors: Dhandapani Ragavesh
Published: November 2024

In this article, a novel method is proposed by using the power of the Internet of Things (IoT) and Machine Learning (ML) to monitor and manage street dustbins effectively. The proposed innovative solution aimed at optimizing waste management processes and improper disposing of the waste in street dustbins. The system involves the installation of sensors in dustbins, which collect real-time data about the fill level of the bins. The capability of the proposed model allows for dynamic adjustment of waste collection schedules, reducing unnecessary trips and thus saving time, energy, and resources. In addition to that, the model is also trained in various waste disposal scenario such as improper disposal, massive garbage dumps, and e-waste. The proposed model is able to predict and report the trained conditions with the 100% accuracy. The system is implemented using Raspberry Pi 4, a single-board computer with the necessary hardware interface. A suitable web interface has been developed to oversee the status of dustbins and provide optimum travel route for collection of waste from the street dustbins. The proposed system not only enhances operational efficiency but also contributes to environmental sustainability.
Preparation and Characterization of Nano Cellulose Particles from Date Palm
Authors: Ali Moosa Al Balushi Noura , Devi Geetha
Published: November 2024

The increased awareness on environmental protection and rising demand for more eco-friendly and renewable materials has resulted in the minimization of fossil fuel consumption. Date palm plantations are an important agricultural crop in the sultanate of Oman and considered as the staple food for millions of people. More than seven million date palms are available in the northern governorates of Oman. Only 50% of the dates produced are utilized for human consumption and the remaining 50% are thrown into the environment, posing threat to human and animal. This improper disposal of discarded dates leads to pollution, habitat degradation, disease transmission, soil contamination, and water pollution, threatening the environment and human/animal health. This research aims to extract nanocellulose particles from three different parts of the date palm tree (i.e coir, front, and leaves) samples using both mechanical and Soxhlet extraction methods at varying processing conditions. The acid hydrolysis of the biomass using H2SO4 (20% v/v) was carried out at 120 °C for 30 min followed by filtration, neutralization, centrifugation and drying to form the particles. The nanocellulose particles were characterized using Scanning Electron Microscopy (SEM) X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Energy Dispersive X-Ray Spectroscopy (EDX), and UV – Visible Spectroscopic analysis. Among the three types of palm residues (coir, front, and leaves), nanocellulose particles derived from coir exhibited better yield (1.5 g), whereas front and leaves has 1.2 g and 0.9 g, yield respectively. The EDX analysis demonstrated 98% purity of nanocellulose indicates the successful extraction. The FTIR spectroscopic analysis demonstrated the existence of hydroxyl groups in nanocellulose at wave numbers corresponding to 3355.69 cm−1, 2916.26 cm−1, and 2914.22 cm−1 respectively for coir, front, and leaf respectively. The XRD analysis demonstrated the crystalline structure of the nanocellulose particles.
Maximizing Date Palm Yield: Automatic Extension Sprinklers for Enhanced Aerial Pollination
Authors: Rehna V J , Naik Sreenivas , Siddique Abid , Al-Shammakhi Nasser , Al-Muqrashi Nahid , Al-Shukri Shafi
Published: November 2024

Date palms require pollen transfer from male to female palms in order to yield a fruitful harvest. The traditional method of accomplishing this artificial cross-pollination involved climbing each palm tree and physically putting male flower spikelets on female inflorescences. This process required a great deal of labor and was time-consuming. Due to developments in farming practices during the modern age, farmers have experimented with mechanical pollination systems. Recently, to pollinate date palms very quickly, safely, affordably, and with a minimum of risk of injury, agricultural drones have been used. In this research, experiments on drone dispersal pollination are conducted on three Omani date palm cultivars—Al Naghal, Al Khanezi, and Al Kasab. The applicability of this method is evaluated by comparing its fruit yield properties to those of the conventional method, which is commonly employed, and the less popular machine/hand pollination methods. The main limitations of drone dispersal pollination are, its inability to disperse exact amount of pollen to the target location of female inflorescences, especially in shorter palms; wastage of pollens and environmental pollution. The study recommends the use of a novel design of extendable pollen sprinkler for target-specific pollination in order to increase pollination efficiency and decrease DPP waste. The designed system comprises of a robotic arm extension with a remotely controlled sprayer mounted on a computer vision android device; that can shoot themselves out to the female flowers and disperse the required amount of pollens in the specific location. This unique spraying mechanism can overcome the drawbacks of aerial pollination and increase its effectiveness.
Design of wastewater treatment unit using End-of-Life (EoL) Reverse Osmosis membrane
Authors: Alauifi Almoatasem , Geetha Devi M.
Published: November 2024

Sultanate of Oman is facing severe challenges due to water scarcity, shortage of rainfall, and limited freshwater resources. Over the past few decades, 90% of the natural water resources are consumed by agriculture. Hence, there is an urgent need to find an alternative to obtain fresh water. Water desalination by Reverse Osmosis (RO) is currently practiced in Oman as freshwater source, since it contributes 80% of the total desalination plants installed worldwide. The RO process results in environmental concerns triggered by emission of gases, and discharge of Reverse Osmosis (RO) membranes. The lifespan of membranes depends on the water quality and the operating conditions, and the membrane life is estimated as 5 to 10 years. In order to mitigate the environmental impact for a sustainable desalination output, reuse of discarded end-of-life (EoL) RO membrane is a feasible solution to enhance the water quality. The efficiency of RO membranes is affected by the fouling, scaling, and chemical cleaning for the yearlong operation which lead to reduced salt rejection rate. Hence, this research aimed to reuse the old RO elements by transforming them into Ultrafiltration unit (UF) by removing the active layer and increasing the pore size of membrane. Additionally, modifying the membrane by open configuration and separating all 28 membrane sheets from the permeating tubes are designed as RO-MBR panels. The study shows that, after 5 weeks of operation, the average turbidity rejection rate was 94%, and the average permeated flux per unit was 6.9 LMH. The new configuration shows the permeate flux stability and acceptable BOD, and COD reduction.
Coupled Tanks Level Control Based on Volume Balance Method
Authors: Ruzhekov Georgi
Published: November 2024

The laboratory bench “Coupled tanks” represents a model of real technological plans where the levels and flow rates of liquids must be controlled. Such training benches are very common and there is a very large number of publications related to their control. All publications work with a non-linear model based on the Bernoulli equation for ideal fluids, which is non-linear – the square root of the fluid height is present. This equation or system of equations is linearized and attempts are made to control such systems by means of linear models. This article shows that this approach is not correct and proposes a completely different one based on the volume balance method.
The Lamé functions and elliptic soliton solutions: Bilinear approach
Authors: Li Xing , Zhang Da-jun
Published: November 2024

The Lamé function can be used to construct plane wave factors and solutions to the Korteweg-de Vries (KdV) and Kadomtsev-Petviashvili (KP) hierarchies. The solutions are usually called elliptic solitons. In this paper, first, we review recent development in the Hirota bilinear method on elliptic solitons of the KdV equation and KP equation, including bilinear calculations involved with the Lamé type plane wave factors, expressions of

τ
\tau

functions and the generating vertex operators. Then, for the discrete potential KdV and KP equations, we give their bilinear forms, derive

τ
\tau

functions of elliptic solitons, and show that they share the same vertex operators with the KdV hierarchy and the KP hierarchy, respectively.
Transcendental Julia sets of positive finite Lebesgue measure
Authors: Wolff Mareike
Published: November 2024

We show that there exists a transcendental entire function whose Julia set has positive finite Lebesgue measure.
Identifying Factors that Increase False-Positive Rates on Embedded Performance Validity Testing in ADHD Evaluations
Authors: Finley John-Christopher A , Tufty Logan M , Abalos Steven A , Keszycki Rachel , Woloszyn Mary , Shapiro Greg , Cerny Brian M , Ulrich Devin M , Phillips Matthew S , Robinson Anthony D , Soble Jason R
Published: November 2024

Objective

This study investigated why certain embedded performance validity indicators (EVIs) are prone to higher false-positive rates (FPRs) in attention-deficit/hyperactivity disorder (ADHD) evaluations. The first aim was to establish the relationship between FPRs and 15 EVIs derived from six cognitive tests when used independently and together among adults with ADHD who have valid test performance. The second aim was to determine which specific EVIs increase the FPRs in this population.

Method

Participants were 517 adult ADHD referrals with valid neurocognitive test performance as determined by multiple performance validity tests and established empirical criteria. FPRs were defined by the proportion of participants who scored below an empirically established EVI cutoff with ≥0.90 specificity.

Results

EVIs derived from two of the six tests exhibited unacceptably high FPRs (>10%) when used independently, but the total FPR decreased to 8.1% when the EVIs were aggregated. Several EVIs within a sustained attention test were associated with FPRs around 11%. EVIs that did not include demographically adjusted cutoffs, specifically for race, were associated with higher FPRs around 14%. Conversely, FPRs did not significantly differ based on whether EVIs included timed versus untimed, verbal versus nonverbal, or graphomotor versus non-graphomotor components, nor whether they had raw versus standardized cut scores.

Conclusions

Findings suggest that practitioners should consider both the type of test from which an EVI is derived and the aggregate number of EVIs employed to minimize the FPRs in ADHD evaluations. Findings also indicate that more nuanced approaches to validity test selection and development are needed.
Semi-supervised learning with pseudo-labeling compares favorably with large language models for regulatory sequence prediction
Authors: Phan Han , Brouard Céline , Mourad Raphaël
Published: November 2024

Predicting molecular processes using deep learning is a promising approach to provide biological insights for non-coding single nucleotide polymorphisms identified in genome-wide association studies. However, most deep learning methods rely on supervised learning, which requires DNA sequences associated with functional data, and whose amount is severely limited by the finite size of the human genome. Conversely, the amount of mammalian DNA sequences is growing exponentially due to ongoing large-scale sequencing projects, but in most cases without functional data. To alleviate the limitations of supervised learning, we propose a novel semi-supervised learning (SSL) based on pseudo-labeling, which allows to exploit unlabeled DNA sequences from numerous genomes during model pre-training. We further improved it incorporating principles from the Noisy Student algorithm to predict the confidence in pseudo-labeled data used for pre-training, which showed improvements for transcription factor with very few binding (very small training data). The approach is very flexible and can be used to train any neural architecture including state-of-the-art models, and shows in most cases strong predictive performance improvements compared to standard supervised learning. Moreover, small models trained by SSL showed similar or better performance than large language model DNABERT2.
Prototype-based contrastive substructure identification for molecular property prediction
Authors: He Gaoqi , Liu Shun , Liu Zhuoran , Wang Changbo , Zhang Kai , Li Honglin
Published: November 2024

Substructure-based representation learning has emerged as a powerful approach to featurize complex attributed graphs, with promising results in molecular property prediction (MPP). However, existing MPP methods mainly rely on manually defined rules to extract substructures. It remains an open challenge to adaptively identify meaningful substructures from numerous molecular graphs to accommodate MPP tasks. To this end, this paper proposes Prototype-based cOntrastive Substructure IdentificaTion (POSIT), a self-supervised framework to autonomously discover substructural prototypes across graphs so as to guide end-to-end molecular fragmentation. During pre-training, POSIT emphasizes two key aspects of substructure identification: firstly, it imposes a soft connectivity constraint to encourage the generation of topologically meaningful substructures; secondly, it aligns resultant substructures with derived prototypes through a prototype-substructure contrastive clustering objective, ensuring attribute-based similarity within clusters. In the fine-tuning stage, a cross-scale attention mechanism is designed to integrate substructure-level information to enhance molecular representations. The effectiveness of the POSIT framework is demonstrated by experimental results from diverse real-world datasets, covering both classification and regression tasks. Moreover, visualization analysis validates the consistency of chemical priors with identified substructures. The source code is publicly available at https://github.com/VRPharmer/POSIT.
Measuring brain perfusion by CT or MR as ancillary tests for diagnosis of brain death: a systematic review and meta-analysis
Authors: Ramos João N , Pinto Catarina , Cruz e Silva Vera , Topriceanu Constantin-Cristian , Bisdas Sotirios
Published: November 2024

Objectives

To gather and synthesize evidence regarding diagnostic accuracy of perfusion imaging by CT (CTP) or MR (MRP) for brain death (BD) diagnosis.

Methods

A systematic review and meta-analysis was prospectively registered with PROSPERO (CRD42022336353) and conducted in accordance with the PRISMA guidelines and independently by 3 reviewers. PubMed/MEDLINE, EMBASE and Cochrane Database were searched for relevant studies. Quality Assessment of Diagnostic Accuracy Studies-2 was used to assess studies’ quality. Meta-analysis was performed using univariate random-effects models.

Results

Ten studies (328 patients) were included. Perfusion imaging (most commonly CTP, n = 8 studies) demonstrated a high sensitivity of 96.1% (95% CI, 89.5-98.6) for BD, consistent in subgroup analysis at 95.5% (95% CI, 86.5-98.6). Unfortunately, it was not feasible to calculate other metrics. Additionally, evidence of publication bias was identified in our findings.

Conclusions

The sensitivity of CTP or MRP for BD diagnosis is very high, comparable to CTA and TCD. However, considering most studies were retrospective, and lacked control groups and unambiguous criteria for perfusion imaging in BD assessment, results should be interpreted with caution. Future studies, ideally prospective, multi-centre, and with control groups are of utmost importance for validation of these methods, particularly with standardized technical parameters.

Advances in knowledge

Cerebral perfusion imaging using CT or MRI demonstrates high sensitivity in diagnosing BD, on par with CTA and TCD. Recommended by the World Brain Death group, this method holds promise for further investigation in this area.

PROSPERO registration number

CRD42022336353
Characterization of Inflammatory Bowel Disease Heterogeneity Using Serum Proteomics: A Multicenter Study
Authors: Salomon Benita , Sudhakar Padhmanand , Bergemalm Daniel , Andersson Erik , Grännö Olle , Carlson Marie , Hedin Charlotte R H , Söderholm Johan D , Öhman Lena ,   the BIO IBD Consortium, the COLLIBRI Consortium, Ungaro Ryan C , Aden Konrad , D’Haens Geert , Silverberg Mark S , Almer Sven , Bresso Francesca , Carstens Adam , D’Amato Mauro , Eriksson Carl , Hjortswang Henrik , Keita Åsa V , Lundström Maria Ling , Magnusson Maria K , Hreinsson Jóhann P , Strid Hans , Lindqvist Carl Mårten , Kruse Robert , Repsilber Dirk , Verstockt Bram , Vermeire Séverine , Halfvarson Jonas
Published: November 2024

Background

Recent genetic and transcriptomic data highlight the need for improved molecular characterization of inflammatory bowel disease (IBD). Proteomics may advance the delineation of IBD phenotypes since it accounts for post-transcriptional modifications.

Aims

We aimed to assess the IBD spectrum based on inflammatory serum proteins and identify discriminative patterns of underlying biological subtypes across multiple European cohorts.

Methods

Using proximity extension methodology, we measured 86 inflammation-related serum proteins in 1551 IBD patients and 312 healthy controls (HC). We screened for proteins exhibiting significantly different levels among IBD subtypes and between IBD and HC. Classification models for differentiating between Crohn’s disease (CD) and ulcerative colitis (UC) were employed to explore the IBD spectrum based on estimated probability scores.

Results

Levels of multiple proteins, such as interleukin-17A, matrix metalloproteinase-10, and fibroblast growth factor-19, differed (fold-change >1.2; false discovery rate <0.05) between ileal versus colonic IBD. Using multivariable models, a protein signature reflecting the IBD spectrum was identified, positioning colonic CD between UC and ileal CD, which were at opposite ends of the spectrum. Based on area under the curve (AUC) estimates, classification models more accurately differentiated UC from ileal CD (median AUCs > 0.73) than colonic CD (median AUCs < 0.62). Models differentiating colonic CD from ileal CD demonstrated intermediate performance (median AUCs: 0.67–0.69).

Conclusions

Our findings in serum proteins support the presence of a continuous IBD spectrum rather than a clear separation of CD and UC. Within the spectrum, disease location may reflect a more similar disease than CD versus UC, as colonic CD resembled UC more closely than ileal CD.
Vitamin D status, physical activity, and long-term mortality risk after myocardial infarction: a prospective analysis in the Alpha Omega Cohort
Authors: Cruijsen Esther , van Pijkeren Claudia S , Evers Ilse , Visseren Frank L J , Geleijnse Johanna M
Published: November 2024

Aims

In post-myocardial infarction (MI) patients, we examined independent and combined associations of vitamin D status and physical activity (PA) with long-term mortality, including effect modification by health determinants.

Methods and results

We conducted a prospective analysis of 4837 MI patients from the Alpha Omega Cohort. Baseline blood samples (2002–06) were assessed for plasma 25-hydroxyvitamin D (25[OH]D) levels. Physical activity was assessed using a validated questionnaire. Patients were followed for mortality through December 2022. Hazard ratios (HRs) for cardiovascular disease (CVD) and all-cause mortality were obtained across sex-specific tertiles of 25(OH)D and four categories of PA using Cox models, adjusted for sociodemographic and lifestyle factors. Potential effect modification by health determinants was examined through stratification. Patients were 69 ± 5.6 years old, 78% was male, 21% had diabetes, and 10% used vitamin D–containing supplements. Over 14.4 years, 3206 deaths occurred, including 1244 from CVD. The median 25(OH)D was 21.1 ng/mL, and 44% was vitamin D deficient (<20 ng/mL). Higher 25(OH)D levels were associated with lower CVD (HR: 0.63, 95% CI: 0.54, 0.74) and all-cause mortality (HR: 0.68, 95% CI: 0.62, 0.75). For PA levels (high vs. light), HRs were 0.72 (95% CI: 0.61, 0.85) for CVD mortality and 0.83 (95% CI: 0.75, 0.92) for all-cause mortality. Patients with low 25(OH)D and no PA had a three-fold higher mortality risk than those with high 25(OH)D levels and high PA. The associations were not significantly modified by sex, comorbidities, and other health determinants.

Conclusion

Vitamin D status and PA were inversely and independently associated with long-term risk of CVD and all-cause mortality after MI, regardless of other health determinants.
Rethinking the aristocracy in Capetian France, 987–1328
Authors: Power Daniel
Published: November 2024

This introduction explains the context for the following set of six articles. It first considers the meaning and use of the terms ‘France’, ‘Capetian’ and ‘aristocracy’ for historians of the Capetian period of French history (987–1328). It then outlines the historiography of the aristocracy of France in the central Middle Ages. In the second half of the twentieth century, much of the historiography in France concentrated upon holistic studies of regional societies rather than more specific studies of the aristocracy. In recent decades, however, there has been a revival of studies of landowning élites in France, and important work on this topic has long been carried out in other countries as well. The introduction concludes with an overview of the six articles in this collection.
Genetic screening reveals cone cell-specific factors as common genetic targets modulating rival-induced prolonged mating in male Drosophila melanogaster
Authors: Sun Yanying , Zhang Xiaoli , Wu Zekun , Li Wenjing , Kim Woo Jae
Published: November 2024

Male–male social interactions exert a substantial impact on the transcriptional regulation of genes associated with aggression and mating behavior in male Drosophila melanogaster. Throughout our comprehensive genetic screening of aggression-related genes, we identified that the majority of mutants for these genes are associated with rival-induced and visually oriented mating behavior, longer-mating duration (LMD). The majority of mutants with upregulated genes in single-housed males significantly altered LMD behavior but not copulation latency, suggesting a primary regulation of mating duration. Single-cell RNA-sequencing revealed that LMD-related genes are predominantly co-expressed with male-specific genes like dsx and Cyp6a20 in specific cell populations, especially in cone cells. Functional validation confirmed the roles of these genes in mediating LMD. Expression of LMD genes like Cyp6a20, Cyp4d21, and CrzR was enriched in cone cells, with disruptions in cone cell-specific expression of CrzR and Cyp4d21 leading to disrupted LMD. We also identified a novel gene, CG10026/Macewindu, that reversed LMD when overexpressed in cone cells. These findings underscore the critical role of cone cells as a pivotal site for the expression of genes involved in the regulation of LMD behavior. This study provides valuable insights into the intricate mechanisms underlying complex sexual behaviors in Drosophila.
Cybersecurity and International Relations: developing thinking tools for digital world politics
Authors: Liebetrau Tobias , Monsees Linda
Published: November 2024

Processes of digital transformation alter global politics. This is an issue not only for specialists in cybersecurity, but for all scholars of international relations. This introduction to a special section outlines an agenda for cybersecurity research in international relations research and practice. We argue that cybersecurity is not only a specialized subfield of International Relations (IR), but also an intellectual space in which crucial questions concerning international politics, security and digital technology can be examined. Nevertheless, we identify three biases in current cybersecurity research—a focus toward the state, the military and power as domination—that limit the field and hamper broader engagement with IR and critical security scholarship. We argue that cybersecurity and digital technology are neither optional additions to the theory and practice of international relations nor issues that can neatly be isolated from other world affairs. The goal of the special section is hence twofold. First, to provide new directions and foundations for cybersecurity studies. Second, to explore the opportunities and challenges raised by cybersecurity and digital technological phenomena in conversation with IR and critical security studies. Taken together, the special section demonstrates the need to understand cybersecurity through international relations and to understand international relations through cybersecurity.
Norm diffusion in cyber governance: China as an emerging norm entrepreneur?
Authors: Chen Xuechen , Gao Xinchuchu
Published: November 2024

In light of China's growing weight as a technological power in the international arena, an increasing body of literature is dedicated to conceptualizing China as a nascent norm-shaper in global cyber governance. However, a nuanced investigation into the process of China's norm diffusion in cyber governance has been lacking. Drawing on the latest advancements from norm diffusion theory, this study provides a nuanced understanding of the complex and multidimensional nature of China's cyber-governance norm cluster and the diffusion mechanisms. By contesting the linear and static conceptualization of norms, this study conceptualizes China's cyber governance norms through the lens of norm cluster. It demonstrates that China has actively promoted a constellation of values and appropriate behaviours in order to address the myriad of problems and challenges it identifies in global cyber governance, revolving around three core values, namely: cyber sovereignty, multilateralism and the balance between security and development. This research also demonstrates that instead of using a single diffusion mechanism, China has relied on a dynamic combination of socialization and positive incentives which are driven by both state-led actors and private sectors to diffuse its cyber norms and approaches at regional and international levels.
The Effectiveness of Oral Vancomycin on Inflammatory Bowel Disease in Patients With Primary Sclerosing Cholangitis: A Systematic Review
Authors: Arbabzada Naik , Dennett Liz , Meng Guanmin , Peerani Farhad
Published: November 2024

Background

Approximately 70% of primary sclerosing cholangitis (PSC) patients have inflammatory bowel disease (IBD). The IBD therapies currently used to treat PSC-IBD patients have side effects and can be costly. Oral vancomycin (OV)—a safe, economical, and convenient therapy—has been reported to be a salvage therapy in refractory PSC-IBD patients. This systematic review aims to summarize the current literature regarding the effectiveness and safety of OV to treat IBD in PSC patients.

Methods

A systematic literature review of Scopus, Embase, Web of Science, MEDLINE, and CINAHL was performed until March 2024. The Murad scale, Newcastle-Ottawa scale, and Cochrane Collaboration Risk of Bias Tool were used to determine the quality of the case reports and case series, cohort studies, and randomized controlled trial (RCT), respectively. The outcomes sought were response or remission across clinical, biochemical, endoscopic, and histological parameters.

Results

Of the 1725 published studies, we identified 9 case reports, 7 case series, 3 cohort studies, and 1 RCT. Most studies reported an improvement in clinical IBD symptoms such as diarrhea and hematochezia. Fewer publications provided supporting objective data in the form of fecal calprotectin, endoscopic Mayo scores, and histology. There were no reports of vancomycin-resistant enterococci infections.

Conclusions

Oral vancomycin appears safe and effective to treat IBD in a subset of PSC patients. Future studies would benefit from prospective data collection incorporating standardized symptomatic, endoscopic, and histologic indices. Ultimately, a well-powered RCT is needed to better assess the effectiveness, safety, and durability of OV therapy.
Bacterial population-level trade-offs between drought tolerance and resource acquisition traits impact decomposition
Authors: Malik Ashish A , Martiny Jennifer B H , Ribeiro Antonio , Sheridan Paul O , Weihe Claudia , Brodie Eoin L , Allison Steven D
Published: November 2024

Microbes drive fundamental ecosystem processes, such as decomposition. Environmental stressors are known to affect microbes, their fitness, and the ecosystem functions that they perform; yet, understanding the causal mechanisms behind this influence has been difficult. We used leaf litter on soil surface as a model in situ system to assess changes in bacterial genomic traits and decomposition rates for 18 months with drought as a stressor. We hypothesized that genome-scale trade-offs due to investment in stress tolerance traits under drought reduce the capacity for bacterial populations to carry out decomposition, and that these population-level trade-offs scale up to impact emergent community traits, thereby reducing decomposition rates. We observed drought tolerance mechanisms that were heightened in bacterial populations under drought, identified as higher gene copy numbers in metagenome-assembled genomes. A subset of populations under drought had reduced carbohydrate-active enzyme genes that suggested—as a trade-off—a decline in decomposition capabilities. These trade-offs were driven by community succession and taxonomic shifts as distinct patterns appeared in populations. We show that trait–trade-offs in bacterial populations under drought could scale up to reduce overall decomposition capabilities and litter decay rates. Using a trait-based approach to assess the population ecology of soil bacteria, we demonstrate genome-level trade-offs in response to drought with consequences for decomposition rates.
Metabolomic Analysis of HUVEC After Thermal Denaturation UHPLC-MS/MS-Based Metabolomics
Authors: Wu Fangqin , Yan Zhuoxian , Ran Yanqin , Wang Mengna , Yang Sifan , Huang Mitao , Zhou Situo , Zhang Pihong , Liang Pengfei , Jiang Bimei
Published: November 2024

Preserving denatured dermis has been shown to promote wound healing and improve skin appearance and function. Angiogenesis is crucial for the healing of burn wounds. However, the metabolic mechanisms underlying angiogenesis during burn recovery remain unclear. In this study, ultra-high performance liquid chromatography-mass spectrometry analysis revealed 6 distinct metabolites in a heat-denatured cell model. A bioinformatics approach was used to predict the differentially expressed metabolites and 4 metabolic pathways closely related to trauma repair were identified. These pathways might play a significant role in the regression of thermally injured endothelial cells. We also found that increasing D-mannose level promoted the angiogenic activity of human umbilical vein endothelial cells in the heat-denatured cell model, enhancing cell proliferation, migration, and tube formation. In summary, these findings revealed changes in metabolites and metabolic pathways in thermally injured endothelial cells and demonstrated that D-mannose could promote angiogenesis during the recovery of thermally injured endothelial cells.