bluuebunny/crossref_metadata_2025 huggingface dataset:
Dysregulation of miRNA–mRNA expression in fetal growth restriction in a caloric restricted mouse model
Authors: Gallagher Lauren T. , Bardill James , Sucharov Carmen C. , Wright Clyde J. , Karimpour-Fard Anis , Zarate Miguel , Breckenfelder Courtney , Liechty Kenneth W. , Derderian S. Christopher
Published: March 2024

Fetal growth restriction (FGR) is associated with aberrant placentation and accounts for a significant proportion of perinatal deaths. microRNAs have been shown to be dysregulated in FGR. The purpose of this study was to determine microRNA-regulated molecular pathways altered using a caloric restricted mouse model of FGR. Pregnant mice were subjected to a 50% caloric restricted diet beginning at E9. At E18.5, RNA sequencing of placental tissue was performed to identify differences in gene expression between caloric restricted and control placentas. Significant differences in gene expression between caloric restricted and control placentas were observed in 228 of the 1546 (14.7%) microRNAs. Functional analysis of microRNA–mRNA interactions demonstrated enrichment of several biological pathways with oxidative stress, apoptosis, and autophagy pathways upregulated and angiogenesis and signal transduction pathways downregulated. Ingenuity pathway analysis also suggested that ID1 signaling, a pathway integral for trophoblast differentiation, is also dysregulated in caloric restricted placentas. Thus, a maternal caloric restriction mouse model of FGR results in aberrant microRNA-regulated molecular pathways associated with angiogenesis, oxidative stress, signal transduction, apoptosis, and cell differentiation. As several of these pathways are dysregulated in human FGR, our findings suggest that this model may provide an excellent means to study placental microRNA derangements seen in FGR.
Biochemical and functional characterization of heat-inactivated coelomic fluid from earthworms as a potential alternative for fetal bovine serum in animal cell culture
Authors: Rossan Mathews Melinda Grace , Subramaniam Ravichandran , Venkatachalam Saravanakumar , Selvan Christyraj Johnson Retnaraj Samuel , Yesudhason Beryl Vedha , Kalimuthu Kalishwaralal , Mohan Manikandan , Selvan Christyraj Jackson Durairaj
Published: March 2024

Fetal bovine serum (FBS) plays a pivotal role in animal cell culture. Due to ethical and scientific issues, searching for an alternative, comprising the three R’s (Refinement, Reduction and Replacement) gained global attention. In this context, we have identified the heat inactivated coelomic fluid (HI-CF) of the earthworm, Perionyx excavatus as a potential alternative for FBS. Briefly, we formulated HI-CF (f-HICF) containing serum free medium which can aid the growth, attachment, and proliferation of adherent cells, similar to FBS. In this study, we investigated the biochemical characterization, sterility, stability, formulation, and functional analysis of HI-CF as a supplement in culturing animal cells. Notably, vitamins, micronutrients, proteins, lipids, and trace elements are identified and compared with FBS for effective normalization of the serum free media. HI-CF is tested to be devoid of endotoxin and mycoplasma contamination thus can qualify the cell culture grade. The f-HICF serum free media was prepared, optimised, and tested with A549, HeLa, 3T3, Vero and C2C12 cell lines. Our results conclude that f-HICF is a potential alternative to FBS, in accordance with ethical concern; compliance with 3R's; lack of unintended antibody interactions; presence of macro and micronutrients; simple extraction; cost-effectiveness and availability.
Development of risk models of incident hypertension using machine learning on the HUNT study data
Authors: Schjerven Filip Emil , Ingeström Emma Maria Lovisa , Steinsland Ingelin , Lindseth Frank
Published: March 2024

In this study, we aimed to create an 11-year hypertension risk prediction model using data from the Trøndelag Health (HUNT) Study in Norway, involving 17 852 individuals (20–85 years; 38% male; 24% incidence rate) with blood pressure (BP) below the hypertension threshold at baseline (1995–1997). We assessed 18 clinical, behavioral, and socioeconomic features, employing machine learning models such as eXtreme Gradient Boosting (XGBoost), Elastic regression, K-Nearest Neighbor, Support Vector Machines (SVM) and Random Forest. For comparison, we used logistic regression and a decision rule as reference models and validated six external models, with focus on the Framingham risk model. The top-performing models consistently included XGBoost, Elastic regression and SVM. These models efficiently identified hypertension risk, even among individuals with optimal baseline BP (< 120/80 mmHg), although improvement over reference models was modest. The recalibrated Framingham risk model outperformed the reference models, approaching the best-performing ML models. Important features included age, systolic and diastolic BP, body mass index, height, and family history of hypertension. In conclusion, our study demonstrated that linear effects sufficed for a well-performing model. The best models efficiently predicted hypertension risk, even among those with optimal or normal baseline BP, using few features. The recalibrated Framingham risk model proved effective in our cohort.
Towards a comprehensive characterization of spatio-temporal dependence of light-induced electromagnetic forces in dielectric liquids
Authors: Astrath N. G. C. , Bergmann E. V. , Anghinoni B. , Flizikowski G. A. S. , Novatski A. , Jacinto C. , Požar T. , Kalin M. , Malacarne L. C. , Baesso M. L.
Published: March 2024

The interaction of localized light with matter generates optical electrostriction within dielectric fluids, leading to a discernible change in the refractive index of the medium according to the excitation’s light profile. This optical force holds critical significance in optical manipulation and plays a fundamental role in numerous photonic applications. In this study, we demonstrate the applicability of the pump-probe, photo-induced lensing (PIL) method to investigate optical electrostriction in various dielectric liquids. Notably, the thermal and nonlinear effects are observed to be temporally decoupled from the electrostriction effects, facilitating isolated observation of the latter. Our findings provide a comprehensive explanation of optical forces in the context of the recently introduced microscopic Ampère electromagnetic formalism, which is grounded in the dipolar approximation of electromagnetic sources within matter and characterizes electrostriction as an electromagnetic-induced stress within the medium. Here, the optical force density is re-obtained through a new Lagrangian approach.
Impact of squatting on selected cardiovascular parameters among college students
Authors: Chukwuemeka Uchechukwu M. , Benjamin Chimdindu P. , Uchenwoke Chigozie I. , Okonkwo Uchenna P. , Anakor Anthony C. , Ede Stephen S. , Fabunmi Ayodeji A. , Amaechi Ifeoma A. , Akobundu Uzoamaka N.
Published: March 2024

Squatting is an active posture test used in assessing baroreflex sensitivity, and the array of patients a physiotherapist handles may benefit from this test to avoid the adverse effects of exercise. Therefore, this study is designed to evaluate the effect of squatting on heart rate and blood pressure among undergraduate students. 35 males (mean age = 22.94 ± 1.846) and 40 females (mean age = 22.28 ± 2.075) participated in this experimental study. Demographic data and baseline cardiovascular parameters (blood pressure and heart rate) were taken before exercise. The exercise protocol, the squatting stress test, was done for 2 min, after which post-exercise blood pressure and heart rate were taken at one minute each. A repeated measure ANOVA and independent t-test were used to analyse the difference at the 0.05 alpha level. It was found that there was a significant difference between pre-exercise in lying and squatting post-exercise blood pressure and heart rate in the first and second minutes (p < 0.01), pre-exercise in lying and standing post-exercise blood pressure and heart rate in the first and second minutes (p < 0.01), pre-exercise in standing and standing post-exercise blood pressure and heart rate in the first and second minutes (p < 0.01), and pre-exercise in standing and squatting post-exercise blood pressure and heart rate in the first and second minutes (p < 0.01). Also, there was a significant difference in pre-exercise heart rate between lying and standing (p < 0.05) and not between the first minute and second minute post-squatting or standing exercise systolic blood pressure (p = 0.588) or diastolic blood pressure (p = 0.22–1). In conclusion, squatting trials among undergraduates revealed some statistically significant changes, especially between the cardiopulmonary parameters obtained in a standing position compared to lying and those measured after one minute. Therefore, caution should be observed when administering exercises that require changes in posture.
Motor oscillations reveal new correlates of error processing in the human brain
Authors: Yordanova Juliana , Falkenstein Michael , Kolev Vasil
Published: March 2024

It has been demonstrated that during motor responses, the activation of the motor cortical regions emerges in close association with the activation of the medial frontal cortex implicated with performance monitoring and cognitive control. The present study explored the oscillatory neurodynamics of response-related potentials during correct and error responses to test the hypothesis that such continuous communication would modify the characteristics of motor potentials during performance errors. Electroencephalogram (EEG) was recorded at 64 electrodes in a four-choice reaction task and response-related potentials (RRPs) of correct and error responses were analysed. Oscillatory RRP components at extended motor areas were analysed in the theta (3.5–7 Hz) and delta (1–3 Hz) frequency bands with respect to power, temporal synchronization (phase-locking factor, PLF), and spatial synchronization (phase-locking value, PLV). Major results demonstrated that motor oscillations differed between correct and error responses. Error-related changes (1) were frequency-specific, engaging delta and theta frequency bands, (2) emerged already before response production, and (3) had specific regional topographies at posterior sensorimotor and anterior (premotor and medial frontal) areas. Specifically, the connectedness of motor and sensorimotor areas contra-lateral to the response supported by delta networks was substantially reduced during errors. Also, there was an error-related suppression of the phase stability of delta and theta oscillations at these areas. This synchronization reduction was accompanied by increased temporal synchronization of motor theta oscillations at bi-lateral premotor regions and by two distinctive error-related effects at medial frontal regions: (1) a focused fronto-central enhancement of theta power and (2) a separable enhancement of the temporal synchronization of delta oscillations with a localized medial frontal focus. Together, these observations indicate that the electrophysiological signatures of performance errors are not limited to the medial frontal signals, but they also involve the dynamics of oscillatory motor networks at extended cortical regions generating the movement. Also, they provide a more detailed picture of the medial frontal processes activated in relation to error processing.
Noise annoyance and cardiovascular disease risk: results from a 10-year follow-up study
Authors: Hahad Omar , Gilan Donya , Michal Matthias , Tüscher Oliver , Chalabi Julian , Schuster Alexander K. , Keller Karsten , Hobohm Lukas , Schmitt Volker H. , König Jochem , Lackner Karl J. , Wild Philipp , Schattenberg Jörn M. , Daiber Andreas , Münzel Thomas
Published: March 2024

The relationship between noise annoyance and risk of cardiovascular disease (CVD) still needs to be fully elucidated. Thus, we examined the relationship between noise annoyance and CVD risk in a large population-based cohort study. Cross-sectional (N = 15,010, aged 35–74 years, baseline investigation period 2007–2012) and prospective data (5- and 10-year follow-up from 2012 to 2022) from the Gutenberg Health Study were used to examine the relationship between noise annoyance due to different sources and risk of prevalent and incident CVD comprising atrial fibrillation, coronary artery disease, myocardial infarction, stroke, chronic heart failure, peripheral artery disease, and venous thromboembolism. In cross-sectional analyses, noise annoyance was an independent risk factor for prevalent CVD, with the strongest associations seen for noise annoyance during sleep (e.g., neighborhood noise annoyance: odds ratio 1.20, 95% confidence interval 1.13–1.27, p < 0.0001). While in the 10-year follow-up, mostly positive associations (although not significant) between noise annoyance and incident CVD were observed, no indication of increased CVD risk was observed after 5 years of follow-up. Noise annoyance due to different sources was associated with prevalent CVD, whereas only weak associations with incident CVD were found. Further large-scale studies are needed to establish the relationship between noise annoyance and risk of CVD.
No evidence of attentional prioritization for threatening targets in visual search
Authors: Zsido Andras N. , Hout Michael C. , Hernandez Marko , White Bryan , Polák Jakub , Kiss Botond L. , Godwin Hayward J.
Published: March 2024

Throughout human evolutionary history, snakes have been associated with danger and threat. Research has shown that snakes are prioritized by our attentional system, despite many of us rarely encountering them in our daily lives. We conducted two high-powered, pre-registered experiments (total N = 224) manipulating target prevalence to understand this heightened prioritization of threatening targets. Target prevalence refers to the proportion of trials wherein a target is presented; reductions in prevalence consistently reduce the likelihood that targets will be found. We reasoned that snake targets in visual search should experience weaker effects of low target prevalence compared to non-threatening targets (rabbits) because they should be prioritized by searchers despite appearing rarely. In both experiments, we found evidence of classic prevalence effects but (contrasting prior work) we also found that search for threatening targets was slower and less accurate than for nonthreatening targets. This surprising result is possibly due to methodological issues common in prior studies, including comparatively smaller sample sizes, fewer trials, and a tendency to exclusively examine conditions of relatively high prevalence. Our findings call into question accounts of threat prioritization and suggest that prior attention findings may be constrained to a narrow range of circumstances.
Pore-scale physics of ice melting within unconsolidated porous media revealed by non-destructive magnetic resonance characterization
Authors: Haile Natnael , Sajjad Muhammad , Zhang Yadong , AlAmoodi Nahla , AlMarzooqi Faisal , Zhang TieJun
Published: March 2024

Melting of ice in porous media widely exists in energy and environment applications as well as extraterrestrial water resource utilization. In order to characterize the ice-water phase transition within complicated opaque porous media, we employ the nuclear magnetic resonance (NMR) and imaging (MRI) approaches. Transient distributions of transverse relaxation timeT2from NMR enable us to reveal the substantial role of inherent throat and pore confinements in ice melting among porous media. More importantly, the increase in minimumT2provides new findings on how the confinement between ice crystal and particle surface evolves inside the pore. For porous media with negligible gravity effect, both the changes in NMR-determined melting rate and our theoretical analysis of melting front confirm that conduction is the dominant heat transfer mode. The evolution of mushy melting front and 3D spatial distribution of water content are directly visualized by a stack of temporal cross-section images from MRI, in consistency with the corresponding NMR results. For heterogeneous porous media like lunar regolith simulant, theT2distribution shows two distinct pore size distributions with different pore-scale melting dynamics, and its maximumT2keeps increasing till the end of melting process instead of reaching steady in homogeneous porous media.
Treatment outcome and survival status among adult patients treated for lupus nephritis in selected tertiary hospitals of Ethiopia
Authors: Aliyi Oumer , Worku Berhanu , Hassen Minimize , Muhammed Oumer Sada
Published: March 2024

Lupus nephritis (LN) is kidney involvement of systematic lupus erythematous that ranges from mild to severe and occurs in 60% of adult patients. Despite advances in therapy, LN morbidity and mortality remains high. There is a paucity of data regarding adult LN patient's treatment outcome, survival status, and associated factors in developing countries, particularly in Ethiopia. This study aimed to assess the treatment outcome, survival status, and associated factors of adult patients treated for LN in two selected tertiary hospitals [Tikur Anbessa Specialized Hospital (TASH) and St. Paul’s Hospital Millennium Medical College (SPHMMC)] of Addis Ababa, Ethiopia. A hospital-based retrospective cross-sectional multicenter study was conducted from January 1, 2016 to January 1, 2021. Socio-demographic, clinical, and treatment-related data were collected from patient’s medical records by using a structured abstraction checklist. Descriptive statistics were used to summarize the quantitative data as appropriate. The modified Aspreva Lupus Management Study (mALMS) criteria was applied to categorize LN treatment outcomes into complete, partial, and non-response. Multinomial logistic regression analysis was performed to identify predictors of LN treatment outcome. Patients’ survival was estimated by using Kaplan–Meier and Cox proportion regression analysis. P value < 0.05 was considered to declare statistical significance. A total of 200 LN patients were included in the final analysis. Amongst these, the majority of them (91.5%) were females. The median age of the patients was 28 (15–60) years. The mean duration of treatment follow-up was 28 months. The commonly prescribed immunosuppressive drugs during both the induction (49.5%) and maintenance (60%) phases were a combination of mycophenolate mofetil with prednisolone. Complete, partial, and non-responses at the last follow-up visit accounted for 66.5%, 18.0%, and 15.5%, respectively. Patient survival at the last follow-up visit was more than 90% for patients with complete response to the induction therapy. Non-response at the last follow-up visit was significantly associated with severe disease activity index (adjusted odds ratio [AOR] = 6.25, 95% confidence interval [CI] 1.49–26.10), presence of comorbidity (AOR = 0.21, 95% CI 0.05–0.92), baseline leucopenia (AOR = 14.2, 95% CI 1.04–201.3), partial response at the end of induction therapy (AOR = 32.63, 95% CI 1.4–736.0), and duration of induction therapy of greater than 6 months (AOR = 19.47, 95% CI 1.5–258.8). This study unveiled that lower numbers of LN patients were presented with non-response at the last follow-up visit and non-response to induction therapy was associated with lower patients’ survival rates compared with complete or partial response.
The effects of physical activity on sleep architecture and mood in naturalistic environments
Authors: Zapalac Kennedy , Miller Melissa , Champagne Frances A. , Schnyer David M. , Baird Benjamin
Published: March 2024

Physical activity has been found to alter sleep architecture, but these effects have been studied predominantly in the laboratory and the generalizability of these findings to naturalistic environments and longer time intervals, as well as their psychological effects, have not been evaluated. Recent technological advancements in wearable devices have made it possible to capture detailed measures of sleep outside the lab, including timing of specific sleep stages. In the current study, we utilized photoplethysmography coupled with accelerometers and smartphone ambulatory assessment to collect daily measurements of sleep, physical activity and mood in a sample of N = 82 over multi-month data collection intervals. We found a robust inverse relationship between sedentary behavior and physical activity and sleep architecture: both low-intensity and moderate-to-vigorous physical activity were associated with increased NREM sleep and decreased REM sleep, as well as a longer REM latency, while higher levels of sedentary behavior showed the opposite pattern. A decreased REM/NREM ratio and increased REM latency were in turn associated with improved wellbeing, including increased energy, reduced stress and enhanced perceived restfulness of sleep. Our results suggest that physical activity and sleep account for unique variance in a person’s mood, suggesting that these effects are at least partially independent.
The stability issue of fractured rock mass slope under the influences of freeze–thaw cycle
Authors: Liu Naifei , Yang Yinliang , Li Ning , Liang Shihao , Liu Hua , Li Cheng
Published: March 2024

Freeze–thaw failure of frozen rock slope often occurs during engineering construction and mining in cold area, which poses a great threat to engineering construction and people's life safety. The properties of rock mass in cold region will change with the periodic change of temperature, which makes it difficult to accurately evaluate the stability of slope under the action of freeze–thaw cycle by conventional methods. Based on field investigation and literature review, this paper discusses the characteristics of frozen rock mass and the failure mechanism of frozen rock slope, and gives the types and failure modes of frozen rock slope. Then, the research status of frozen rock slope is analyzed. It is pointed out that the failure of frozen rock slope is the result of thermo-hydro-mechanical (THM) coupling. It is considered that freeze–thaw cycle, rainfall infiltration and fracture propagation have significant effects on the stability of frozen rock slope, and numerical simulation is used to demonstrate. The research shows that the safety factor of frozen rock slope changes dynamically with the surface temperature, and the safety factor of slope decreases year by year with the increase of freeze–thaw cycles, and the fracture expansion will significantly reduce the safety factor. Based on the above knowledge, a time-varying evaluation method of frozen rock slope stability based on THM coupling theory is proposed. This paper can deepen scholars' understanding of rock fracture slope in cold area and promote related research work.
Structural design and dynamic characteristics analysis of braided composite two-stage gear transmission system
Authors: Zhang Weiliang
Published: March 2024

In order to realize the lightweight design of the transmission system, the braided composite material is applied to the two-stage gear transmission system. According to the structural characteristics of the two-stage gear reducer box, the whole box is designed to be assembled with the braided base and the box wall. Woven composite materials are applied to the web parts of mixed metal composite gears to realize the design goal of lightweight gears. Then, under the assumption of ignoring the influence of friction, bearings and other factors on the system, the dynamic model of the two-stage gear transmission system considering the box is established. By normalizing and dimensionless processing of the equations, the dimensionless differential equations of motion are obtained. The fourth-order Runge–Kutta method is used to analyze the relationship between the connection parameters and the dynamic characteristics of the system under the two working conditions of rigid and flexible connection between the composite base and the box wall.Through the analytical analysis of vibration displacement of two-stage gear reducer and box, the theoretical basis is found for the numerical analysis results. Finally, the dynamic characteristics of the transmission system are studied by vibration resonance analysis through high and low frequency interference. It is found that in a certain frequency range, with the decrease of the mass and moment of inertia of the transmission parts corresponding to the mixed metal composite gear, the amplitude-frequency characteristic Q of the lightweight gear and gearbox transmission system is slightly lower than that of the common gear and gearbox system, and the stability of the system is increased, and the dynamic characteristics of the system are improved.
A novel fluorescent probe with a large Stokes shift for colorimetric and selective detection of cysteine in water, milk, cucumber, pear and tomato
Authors: Luo Lin , Guo Ranran , Wang Lianjie , Song Xixi , Wang Zhao , Wu Junliang
Published: March 2024

A novel fluorescent probe for colorimetric and selective detection of cysteine was efficiently constructed through a simple and mild reaction conditions. Probe 2 displays a linear response to Cys concentrations (0–30 μM), low detection limit (0.89 μM), large Stoke shift (125 nm).
Pd-catalyzed divergent regioselective annulation of phosphinyl allenes accessing polyarylfurans and 2H-chromenes
Authors: Li Yang , Yan Xiao-Long , Hu Li-Yan , Luo Kai , Zhu Jie , Wu Lei
Published: March 2024

A novel and efficient regioselective annulation of phosphinyl allenes with 2-bromophenol or 1-bromo-2-naphthol is achieved by palladium catalysis.
Sustainable energy storage: Mangifera indica leaf waste-derived activated carbon for long-life, high-performance supercapacitors
Authors: Hegde Shreeganesh Subraya , Bhat Badekai Ramachandra
Published: March 2024

This study provides a promising route for utilizing waste biomass as a low-cost, sustainable electrode material for energy storage devices.
Novel aromatic moieties-modified poly(glycidyl amine)s with potent siRNA delivery and cancer treatment effect
Authors: Shuai Qi , Xie Wanxuan , Chen Siyuan , Su Huahui , Yan Yunfeng
Published: March 2024

A novel PGAm-based polymer library was developed for effective siRNA delivery. Compared with their analogue PEI, these polymer carriers exhibited improved biocompatibility and reduced protein adsorption, as well as high delivery efficacy.
Low-temperature open-atmosphere growth of WO3 thin films with tunable and high-performance photoresponse
Authors: Sun Zhuotong , Bhattacharjee Subhajit , Xiao Ming , Li Weiwei , Hill Megan O , Jagt Robert A. , Delumeau Louis-Vincent , Musselman Kevin P. , Reisner Erwin , MacManus-Driscoll Judith
Published: March 2024

In-situ orientation tuning of WO3 thin films with high crystallinity is achieved with a low-temperature and open-atmosphere deposition technique. The fabricated devices showed a significant change in photo-response for film orientation.
Potential molecular qubits with long coherence time constructed using bromo-substituted trityl radicals
Authors: Zhang Yu-Shuang , Fan Yi-Fei , Tao Xing-Quan , Li Geng-Yuan , Deng Qing-Song , Liu Zheng , Wang Ye-Xin , Gao Song , Jiang Shang-Da
Published: March 2024

Bromo-substituted trityl radicals with long room-temperature quantum coherence are expected to be the future generation of molecular-based quantum bits.
Green and efficient piezocatalytic hydrogen production achieved by modifying SrBi4Ti4O15 with CdSe
Authors: Hou Tiancheng , Chen Longbin , Yang Yaodong , Wang Jialong , Yang Tianzi , Rao Wei-Feng
Published: March 2024

The mechanical vibration-assisted piezoelectric catalytic water splitting for hydrogen production is a promising approach to address the energy crisis.
Titanium nitride-based hyperbolic metamaterial for near-infrared ultrasensitive sensing of microbes
Authors: Sarker Dip , Zubair Ahmed
Published: March 2024

An ultrasensitive near-infrared hyperbolic metamaterial-based microbe sensor using titanium nitride nanowire was engineered and analyzed.
Electrochemical dehydroxymethylative functionalization of alkanols for forging C(sp3)–heteroatom bonds
Authors: Zhao Lulu , Tian Jian , Yuan Qilin , Zhong Qiwen , Luo Mengqi , Yang Chao , Guo Lin , Xia Wujiong
Published: March 2024

Electrochemical dehydroxymethylative functionalization reactions of aliphatic alcohols with diverse nucleophiles are herein reported.
Design, synthesis and evaluation of structurally diverse polycyclic harmaline scaffolds as anticancer agents
Authors: Chen Shuang , Wang Xi-Rui , Wang Wei-Na , Xu Ke-Lan , Hu Pan , Zhou Ying , Pan Bo-Wen , Wang Qi-Lin , Liu Xiong-Li
Published: March 2024

This is the first example of harmaline scaffolds as acceptor/acceptor-based N–C–C synthons and evaluation of 3at as an anticancer agent.
Advancement in the C–H bond alkylation of (hetero)arenes catalyzed by the most abundant transition metal–iron
Authors: Pradhan Chandini , Punji Benudhar
Published: March 2024

Advancement in the direct C–H bond alkylation of arenes and heteroarenes using the catalysts based on the most abundant transition metal, iron, is summarized.
First-principles study on the electronic properties of biphenylene, net-graphene, graphene+, and T-graphene based nanoribbons
Authors: Zhou Wensheng , Luo Cheng , Chao Yun , Xiong Songbo , Long Menegqiu , Chen Tong
Published: March 2024

As the width changes, some new carbon based nanoribbons transition from semiconductors to metals and an obvious NDR characteristic can be found in designed devices.
Molecular engineering of polymeric carbon nitride for photocatalytic hydrogen production with ultrahigh apparent quantum efficiency
Authors: Liu Haiyang , Liu Xiaolu , Xu Chengqun , Wang Dongyu , Li Dezhi , Huang Jingyao , Wu Shengquan , Wang Zhichun , Pan Hui
Published: March 2024

Molecular engineering of polymeric carbon nitride promotes the generation of a nanorod structure with ultrahigh AQE for PHE.
Prospect of high-temperature superconductivity in layered metal borocarbides
Authors: Tomassetti Charlsey R. , Kafle Gyanu P. , Marcial Edan T. , Margine Elena R. , Kolmogorov Aleksey N.
Published: March 2024

A large-scale ab initio search for conventional superconductors has revealed new thermodynamically stable and metastable layered metal borocarbides expected to form under ambient pressure and display critical temperatures exceeding 70 K.
DOA estimation based on sparse Bayesian learning with moving synthetic virtual array
Authors: Zhu Chao , Deng Zhenmiao
Published: March 2024

In scenarios with constrained physical aperture sizes, aiming to enhance the resolution and accuracy of Direction of Arrival (DOA) estimation, this paper proposes a novel approach that integrates a moving synthetic virtual array with Sparse Bayesian Learning (SBL) for DOA estimation. Initially, a virtual array is constructed based on the motion characteristics of the target. Subsequently, the SBL method is employed to estimate the DOA of the target. Simulation experiments validate the effectiveness of this approach, demonstrating comparable DOA estimation performance to synthetic aperture methods with larger aperture sizes, even in situations with limited aperture expansion. Furthermore, under constant virtual aperture expansion, this method surpasses non‐SBL methods regarding DOA resolution.
IDR: Intent‐driven routing strategy for reliable and cost‐effective multicasting in airborne tactical networks
Authors: Pan Ying , Lyu Na , Yang Chungang
Published: March 2024

Traditional multicast routing strategies can hardly meet the demanding requirements of multicasting mission assignment messages in airborne tactical networks. This letter proposes an intent‐driven routing strategy, termed as IDR, to realize reliable and efficient multicast. IDR exploits bit index explicit replication technique to encode not only the destination information but also the retransmission information into packet headers. If part of the multicast members failed to receive the packet, IDR can perceive the error and retransmit the packet to the precise set of nodes. Compared to the state‐of‐the‐art reliable multicast routing methods, IDR can enhance multicast retransmission success rate by about 10% or more and reduce retransmission overhead by around 50%.
Iron loss calculation model of high‐voltage multi‐pole asynchronous motors considering high harmonic flux density
Authors: Xiao Shiyong , Xue Lizhu , Qi Shuai , Zhang Weihao
Published: March 2024

A variable coefficient segmented iron loss calculation model is proposed for high‐voltage multi‐pole asynchronous motors, which fully considers the influence of high‐order harmonic magnetic density on such motors. This model introduces additional hysteresis loss, improved eddy current loss coefficients, and rotation magnetisation coefficients to account for changes in losses due to small hysteresis loops and skin effect, as well as rotation magnetisation losses. A 710 kW 10‐pole asynchronous motor is used as the research object. A full‐domain iron loss calculation model considering stator and rotor tooth top surface losses is developed. The model can be used to accurately calculate the overall and local harmonic iron losses in the stator and rotor cores of high‐voltage multi‐pole asynchronous motors. And quantitatively analyse the distribution pattern of any harmonic iron loss at any location in the motor core. It realises the refinement calculation and analysis of iron losses in the whole domain of high‐voltage multi‐pole asynchronous motor. Finally, no‐load and load tests were conducted on the 710 kW 10‐pole asynchronous motor. The iron losses of the 710 kW 10‐pole asynchronous motor at no load and load are calculated using the above mentioned model and the classical trinomial constant factor model. The results are compared with the measured iron loss values. It is proved that the iron loss model is more accurate in calculating the iron loss of high‐voltage multi‐pole asynchronous motor. The result helps researchers to calculate the iron loss distribution of high voltage motors more accurately. Thus, the design and operating parameters of the motor can be optimised to improve the efficiency and performance of the motor. It provides the necessary technical support and key basis for the reduction of loss and energy saving of high‐voltage motors and the optimisation of their core structure.
Quad‐active‐bridge converter with flexible power flow based on LC series resonance decoupling for renewable energy charging stations
Authors: Xia Nenghong , Mao Xike , Yan Shuang , Ma Huaqi , Chen Mengqi
Published: March 2024

Integration of photovoltaic panels (PV) with electric vehicle (EV) charging stations could reduce the grid impact and carbon footprint from the extensive fast and ultra‐fast charging. This paper introduces a decoupled quad‐active‐bridge converter (QAB) with multi‐directional power flow capability, which can integrate PV, energy storage (ES), grid, and EV in a charging station and rule the power among them. As the number of ports increases in the multiple‐active‐bridge converter, the complexity of control increases exponentially because of power decoupling. For the QAB, by tuning one port in series with LC units, the decoupling is achieved between the other three ports, reducing the control difficulty significantly. Further, the resonance decoupling method is extended to the n‐port converter. For different power flows, the system automatically switches between different resonance modes to form higher‐efficiency power flow channels. Three operating modes with decoupled closed‐loop control methods have been constructed for the QAB to be suitable for future charging stations: (1) Charging mode: PV, ES, and grid coordinate with each other to provide incessant and stable charging for EV. (2) Electricity sales mode: Gird is supplied by PV, ES, and EV flexibly. (3) Under no load, PV power is stored locally. Experimental waveforms were presented by a 1‐kW prototype, verifying the effectiveness of power decoupling and the feasibility of the three operating modes.
Enhanced power supply circuitry with long duration and high‐efficiency charging for indoor photovoltaic energy harvesting internet of things end device
Authors: Wang Chung‐Hsiang , Huang Kuo‐Hsuan , Wu Chung‐Yen
Published: March 2024

Light is a popular choice as an indoor energy source for Internet of Things (IoT) end devices. However, indoor light sources are intermittent, which can disrupt the operation of IoT end devices, potentially leading to safety concerns or inaccurate data. Therefore, there is a growing need to develop a long‐duration power supply for IoT end devices. The energy from ambient light is harnessed to charge a supercapacitor through an energy manager chip. This supercapacitor serves as the power source for IoT nodes when the ambient light is unavailable. Nevertheless, as the voltage of the supercapacitor drops below the operating threshold, the IoT end node will eventually shut down. This paper proposes a circuit that utilizes a Joule Thief circuit, booster converter, and capacitor stack‐up circuit to extract the remaining energy from the supercapacitor and boost the voltage, thereby extending the operational lifespan of IoT end nodes. Additionally, capacitor stack‐up circuits significantly enhance charging efficiency. PSpice design and simulations confirm circuit feasibility. High‐efficiency charging and long‐duration IoT nodes suggest replacing traditional batteries with supercapacitors, reducing environmental impact.
A new born‐approximation approach to compute the effects of motion on the solution of electromagnetic problems involving moving materials with stationary boundaries
Authors: Raffetto Mirco , Clemente Vargas Mario Rene , Zeyde Kirill
Published: March 2024

The non‐relativistic motion of media induces very weak effects on electromagnetic fields. For this reason, it is extremely difficult to compute such effects with traditional techniques. To overcome this difficulty, a novel approach is introduced in this work. It is based on the Born approximation of the solution of electromagnetic problems involving media in motion. The formulation of these problems makes use of equivalent field sources and is specifically tailored to find the effects of motion on the electromagnetic field. The new methodology exploits traditional simulators able to deal with media at rest. The motion of the materials has to be managed by specific programs performing simple algebraic calculations. The simplest of the methods proposed does not present any additional complexity with respect to more traditional approaches to the same problems. All methods deal with time‐harmonic electromagnetic fields and, for this reason, they can manage materials in motion with stationary boundaries. A complete set of simulations for cylinders moving in the axial direction show that the new methods outperform traditional numerical approaches and, in some significant cases, traditional approaches based on semi‐analytical techniques. The good features of the new methodology are shown to hold true for a range of velocity values spanning 11 decades; such a range covers most of the applications of practical interest.
Fast fitting of spectral lines with Gaussian and hyperfine structure models
Authors: Juvela Mika , Tharakkal Devika
Published: March 2024

Context. The fitting of spectral lines is a common step in the analysis of line observations and simulations. However, the observational noise, the presence of multiple velocity components, and potentially large data sets make it a non-trivial task.

Aims. We present a new computer program Spectrum Iterative Fitter (SPIF) for the fitting of spectra with Gaussians or with hyperfine line profiles. The aim is to show the computational efficiency of the program and to use it to examine the general accuracy of approximating spectra with simple models.

Methods. We describe the implementation of the program. To characterise its performance, we examined spectra with isolated Gaussian components or a hyperfine structure, also using synthetic observations from numerical simulations of interstellar clouds. We examined the search for the globally optimal fit and the accuracy to which single-velocity-component and multi-component fits recover true values for parameters such as line areas, velocity dispersion, and optical depth.

Results. The program is shown to be fast, with fits of single Gaussian components reaching on graphics processing units speeds approaching one million spectra per second. This also makes it feasible to use Monte Carlo simulations or Markov chain Monte Carlo calculations for the error estimation. However, in the case of hyperfine structure lines, degeneracies affect the parameter estimation and can complicate the derivation of the error estimates.

Conclusions. The use of many random initial values makes the fits more robust, both for locating the global χ2 minimum and for the selection of the optimal number of velocity components.
Study on program methods for energy monitoring of buildings
Authors: Khudayarov Muzaffar , Kurbonov Sarvar
Published: March 2024

Energy monitoring is one of the effective measures aimed at reducing and maintaining energy consumption of residential and public buildings at the proper level, taking into account climatic factors. This article provides information about the process of monitoring the energy consumption of a building. A brief analysis of methods for monitoring the energy consumption of different types of buildings has been conducted. In particular, the methods of "Control and Normalization" based on the Energy-Temperature diagram based on the operating mode of the building are considered. In addition to the methods, information is provided on the information system "energy monitoring of buildings" developed on their basis. Also presented the process of implementing energy monitoring using the developed information system. The use of energy monitoring makes it possible to determine overconsumption in a timely manner and due to this to optimize the current level, as well as to determine the target values of energy consumption in buildings.
Rheological properties of polymer solutions and ways to improve the efficiency of development of high-viscosity oil fields in Uzbekistan
Authors: Agzamov Avaz , Zakirov Azamjon , Igamberdieva Lobar , Agzamova Sevara
Published: March 2024

The results of experimental research on studying the filtration properties of polymer solutions and the mechanism of the displacement process in porous medium were presented in this article. The methodology of experimental studies in a specially designed laboratory setup is given. In the present work the rheological properties of polymer K-9 are considered. At the same time, the relaxation time of viscoelastic particles of K-9 polymer filtered in porous medium is experimentally found. Also, the results of experimental studies on oil displacement of fields with high content of asphaltene-resinous substances by polymer solutions on artificially created reservoir models to determine the optimal concentration of polymer solution and the size of the rim with the purpose of increasing oil recovery. Experimental studies on displacement of high-viscosity oils with a thickened water rim established that this method gives the greatest increase in water-free and ultimate oil recovery of reservoirs, within the range of change in the concentration of polymer solution 0.2-0.4%, with the size of the rim more than 70% of the oil saturated volume of the reservoir. Studies on displacement of high-viscosity oils by polymer solutions show that the use of this method of increasing oil recovery factor in practice is not always economically feasible, because of the need to ensure high injection pressures and high concentration of expensive polymer solution.
Widely Employed Constitutive Material Models in Abaqus FEA Software Suite for Simulations of Structures and Their Materials: A Brief Review
Authors: Anas S.M. , Tahzeeb Rafat , Al-Dala’ien Rayeh Nasr , Alam Mehtab , Shariq Mohd
Published: March 2024

The structural response of masonry/concrete structures depends upon the load-carrying mechanism and subsequently deformations produced by loads carried. In masonry/concrete structures, identification of the stress/strain imposing stress conditions and strain hardening/softening makes the structural response more complicated. Elastic damage models or elastic-plastic constitutive laws are inadequate to simulate masonry/concrete response under high strain-rate loadings. Further, irreversible or plastic strain cannot be realized using the elastic damage model. Several constitutive damage models are available in the literature. In this article, a concise explanation of the functioning of different material models in the Abaqus software package has been provided. These models include concrete damage plasticity for concrete and masonry, traction separation constitutive laws for brick-mortar interface, Hashin's criteria for CFRP, Johnson-Cook plasticity for steel, and crushable foam plasticity hardening for metallic foams. Researchers frequently utilize these models for numerical simulations and modeling of infrastructural elements and their respective materials when subjected to various structural loads. Besides, this paper presents a discourse on problem-solving methods and a comparison between explicit and implicit analysis. The research provides valuable input to researchers and practitioners in the field of structural engineering for an in-depth understanding of the functioning of Abaqus' pre-existing material models.
Research of a modern energy-saving model of the enclosing structure of civil buildings from efficient insulations
Authors: Asatov Nurmuhamat , Djurayev Uktam , Aliyev Mashrab , Sagatov Bakhodir , Abdurakhmonov Azizjon
Published: March 2024

This article examines a modern energy-saving model of the enclosing structure of civil buildings made of effective insulation materials, which varies with different physics and mechanical properties, and complex studies of operational properties and calculations using the developed model of thermal insulation durability made it possible to obtain predictive values of the durability of various types of thermal insulation materials in the construction of wall fencing and make suggestions according to rational areas of application, incl. depending on the degree of capital of the building and the service life of the enclosing structures
A Non-destructive Method for the determination of Carbonation Time for Nominal Concrete Cover Depth Using Non-Linear En-semble Prediction
Authors: Malami Salim Idris , Akpinar Pinar
Published: March 2024

Carbonation, a process involving the reaction of carbon dioxide and moisture, results in the for-mation of powdery calcium carbonate, a critical durability issue causing reinforcement corrosion. The study analyzed carbonation data from coastal and inland buildings in the Turkish Republic of Northern Cyprus, re-vealing higher carbonation rates than anticipated within their lifespan. An artificial intelligence model named Support Vector Machine (SVM) was applied to predict carbonation time (T) to penetrate concrete cover of 25mm in the TRNC. Subsequently used two ensemble techniques, namely Neural Network Ensembles (NNE) and Support Vector Machine Ensembles (SVME) to enhance the performance of the prediction of T. Four performance criteria namely Correlation Coefficient (CC), Root Mean Square Error (RMSE), Correlation Co-efficient (R2), Mean Absolute Error (MAE) was applied to verify the modelling accuracy. The Values of R2 of Ensemble techniques indicated significant increase in the performance, greater than the SVM model. This shows that using ensemble techniques is promising in getting better predictions of carbonation time (T) to penetrate concrete cover. The results obtained showed that NNE and SVME combination demonstrated the best performance under the evaluation criteria of R2 = 0.8721 and R2 = 0.8644 in testing phases respectively in comparison SVM-M1 to SVM-M3.