bluuebunny/crossref_metadata_2025 huggingface dataset:
Endometrial decidualization status modulates endometrial microvascular complexity and trophoblast outgrowth in gelatin methacryloyl hydrogels
Authors: Zambuto Samantha G. , Theriault Hannah , Jain Ishita , Crosby Cody O. , Pintescu Ioana , Chiou Noah , Oyen Michelle L. , Zoldan Janet , Underhill Gregory H. , Harley Brendan A. C. , Clancy Kathryn B. H.
Published: June 2024

The endometrium undergoes rapid cycles of vascular growth, remodeling, and breakdown during the menstrual cycle and pregnancy. Decidualization is an endometrial differentiation process driven by steroidal sex hormones that is critical for blastocyst-uterine interfacing and blastocyst implantation. Certain pregnancy disorders may be linked to decidualization processes. However, much remains unknown regarding the role of decidualization and reciprocal trophoblast-endometrial interactions on endometrial angiogenesis and trophoblast invasion. Here, we report an engineered endometrial microvascular network embedded in gelatin hydrogels that displays morphological and functional patterns of decidualization. Vessel complexity and biomolecule secretion are sensitive to decidualization and affect trophoblast motility, but that signaling between endometrial and trophoblast cells was not bi-directional. Although endometrial microvascular network decidualization status influences trophoblast cells, trophoblast cells did not induce structural changes in the endometrial microvascular networks. These findings add to a growing literature that the endometrium has biological agency at the uterine-trophoblast interface during implantation. Finally, we form a stratified endometrial tri-culture model, combining engineered microvascular networks with epithelial cells. These endometrial microvascular networks provide a well-characterized platform to investigate dynamic changes in angiogenesis in response to pathological and physiological endometrial states.
Transmission electron imaging and diffraction of asbestos fibers in a scanning electron microscope
Authors: Holm Jason D. , Mansfield Elisabeth
Published: June 2024

Transmission electron imaging and diffraction analysis of asbestos is straightforward in SEMs, thereby improving analytical accessibility and enabling field-deployable test methods with potential for reduced instrumentation cost compared to TEM.
Enhanced H2 production assisted by anodic iodide oxidation using transparent tin oxide-based electrodes
Authors: Paniya Shraddha , Vankayala Kiran
Published: June 2024

Transparent conducting oxides (TCOs) such as FTO and ITO are efficient catalysts for iodide oxidation reaction (IOR). Iodide oxidation reaction boosts H2 evolution in hybrid water electrolysis.
Catalyst development for O2-assisted oxidative dehydrogenation of propane to propylene
Authors: Liu Huimin , Sun Shaoyuan , Li Dezheng , Lei Yiming
Published: June 2024

In this review, we have summarized mainstream catalyst development in O2-assisted oxidative dehydrogenation of propane to propylene for providing a clear picture to catalysis community.
Fluorescence-enhanced supra-amphiphiles based on pillar[5]arene: construction, controllable self-assembly and application in cell imaging
Authors: Fang Lizhen , Dai Yu , Bai Yiqiao , Meng Yujia , Yu Wenqiang , Gao Yunhan , Tang Ruowen , Zhang Yue , Li Liang , Wang Jin , Ding Yue , Wang Yang , Chen Tingting , Cai Yan , Yao Yong
Published: June 2024

Fluorescence-enhanced supra-amphiphiles based on (WP5)2⊃ENDTn were constructed successfully. When n = 9, they can self-assemble into uniform micelles with an average diameter of about 90 nm and be further applied in cell imaging.
Multiscale characterizations of structural evolution in mesoporous CeO2
Authors: Li Tianyu , Rodriguez Efrain E.
Published: June 2024

In situ ultra-small-angle and wide-angle X-ray scattering enables simultaneous tracking of the structural parameters of mesoporous CeO2 from the atomic scale to the micron-size scale.
Molecular engineering of metal-based photosensitizers with narrow band gap for efficient photodynamic therapy
Authors: Shi Pengmin , Gong Wenqi , Zhao Jian , Jiao Yubo , Sun Yanyan , Fang Lei , Gou Shaohua
Published: June 2024

Three iridium(iii) complexes were designed with the purpose of investigating the photo-physicochemical behaviors of iridium(iii) complexes with narrow band gap for photodynamic therapy.
A statistical theory of the photoluminescence determination of the band gap energy in nano-crystals and layered materials
Authors: Santamaría-Holek I. , Pérez-Madrid A.
Published: June 2024

Statistical mechanics explains the abnormal bandgap energy temperature dependence in nanocrystals and 2D materials via energy/thermal-energy ratio invariance.
An efficient alkoxy-substituted polymer acceptor for efficient all-polymer solar cells with low voltage loss and versatile photovoltaic applications
Authors: Yu Han , Zhao Chaoyue , Hu Huawei , Zhu Shenbo , Zou Bosen , Dela Peña Top Archie , Ng Ho Ming , Kwok Chung Hang , Yi Jicheng , Liu Wei , Li Mingjie , Wu Jiaying , Zhang Guangye , Chen Yiwang , Yan He
Published: June 2024

All-polymer solar cells with low voltage loss for efficient outdoor and indoor photovoltaics.
Synthesis of a new series of 4-pyrazolylquinolinones with apoptotic antiproliferative effects as dual EGFR/BRAFV600E inhibitors
Authors: Al-Wahaibi Lamya H. , Youssif Bahaa G. M. , Abou-Zied Hesham A. , Bräse Stefan , Brown Alan B. , Tawfeek Hendawy N. , El-Sheref Essmat M.
Published: June 2024

A series of new pyrazolylquinolin-2-ones were designed and synthesised. The structures of the new compounds were validated by IR, NMR, and elemental analysis. The new compounds were evaluated as antiproliferative agents targeting EGFR and BRAFV600E.
Enantioselective vinylogous aldol reaction between β,γ-unsaturated amides and isatins
Authors: Hu Jun-Yi , Fu Jun-Hao , Li Tian-Ze , Sha Feng , Wu Xin-Yan
Published: June 2024

A highly enantioselective vinylogous aldol reaction between β,γ-unsaturated amides and isatins has been developed to provide chiral multifunctional 3-hydroxy-2-oxindoles.
The new dual anion solvent-free nickel complex based on the pyridine-4-carbohydrazide ligand
Authors: Kuang Bao-long , Zhao Bin-shan , Lu Zu-jia , Wang Ting-wei , Xie Zhi-ming , Sun Mou , Yu Qi-yao , Zhang Jian-guo
Published: June 2024

The first dual anion nickel complex has been prepared, and its structure and properties were studied. This complex possessed excellent detonation performance (D = 6350 m s−1 and P = 16.7 GPa) and insensitivity (IS = 40 J and FS = 360 N).
Advances, opportunities, and challenges in methods for interrogating the structure activity relationships of natural products
Authors: Ancajas Christine Mae F. , Oyedele Abiodun S. , Butt Caitlin M. , Walker Allison S.
Published: June 2024

This review highlights methods for studying structure activity relationships of natural products and proposes that these methods are complementary and could be used to build an iterative computational-experimental workflow.
Research on the preparation and performance of Ni2P@MOF composite nanomaterials
Authors: Zhang Dong , Chen YaLong , Zhou XiaoMing , Zhang He , Bai Jing , Cao Dingming , Guo Kun , Liu JiaAn
Published: June 2024

The minimum RL value for the Ni2P@MOF in the graph is −27 dB, with an effective absorption rate of 90% and an effective bandwidth of 6 GHz. Thus, it emerges as a high-performance absorbing material with significant potential applications.
Advancing nucleic acid delivery through cationic polymer design: non-cationic building blocks from the toolbox
Authors: Porello Ilaria , Bono Nina , Candiani Gabriele , Cellesi Francesco
Published: June 2024

The rational integration of non-cationic building blocks into cationic polymers can be devised to enhance the performance of the resulting gene delivery vectors, improving cell targeting behavior, uptake, endosomal escape, toxicity, and transfection efficiency.
A luminescent supramolecular polymer based on a stiff-stilbene bridged pillar[5]arene as a Pd2+-responsive smart material
Authors: Wu Jing , Liang Chuanyun , Zhao Jianyi , Zuilhof Han , Zhao Hongxia
Published: June 2024

A luminescent supramolecular polymer based on a novel stiff-stilbene bridged pillar[5]arene and a TPE derivative, serving as a Pd2+ responsive smart material.
Manipulating electron redistribution between iridium and Co6Mo6C bridging with a carbon layer leads to a significantly enhanced overall water splitting performance at industrial-level current density
Authors: Li Weimo , Gou Wenqiong , Zhang Linfeng , Zhong Mengxiao , Ren Siyu , Yu Guangtao , Wang Ce , Chen Wei , Lu Xiaofeng
Published: June 2024

Ir nanoparticles on Co6Mo6C nanofibers bridging with a carbon layer have been fabricated as efficient bifunctional electrocatalysts for water splitting, presenting ultrahigh electrocatalytic performance at ampere-level current density.
Supramolecular engineering cascade regulates NIR-II J-aggregates to improve photodynamic therapy
Authors: Wang Huizhe , Liu Huijia , Li Wenqing , Li Shuai , Zhang Jiaqi , Zang Jingzhe , Liu Li , Wang Peng
Published: June 2024

Rational design of small organic molecule-based NIR-II photosensitizers (PSs) with high singlet oxygen quantum yield in aqueous solution for deep tissue imaging and cancer therapy still presents challenges.
Chemo-, regio-, and stereoselective tetrafunctionalization of fluoroalkynes enables divergent synthesis of 5-7-membered azacycles
Authors: Chen Jia-Wei , Ji Wen-Jun , Huang Xue-Ying , Ge Danhua , Shen Zhi-Liang , Guo Kai , Chu Xue-Qiang
Published: June 2024

A 1,2,3,4-tetrafunctionalization of polyfluoroalkynes for the divergent construction of 5-7-membered (E)-1,2-difluorovinyl azacycles is developed.
Specific emitter identification by wavelet residual network based on attention mechanism
Authors: Shi Wenqiang , Lei Yingke , Jin Hu , Teng Fei , Lou Caiyi
Published: June 2024

Specific emitter identification technology plays a very important role in spectrum resource management, wireless network security, cognitive radio etc. However, in complex electromagnetic environments, the variability and uncertainty of signals make it very difficult to extract representative feature representations of the signals. At the same time, the feature extraction capability of the recognition model is also a factor that needs to be considered. To address these issues, a wavelet residual neural network model based on attention mechanism is proposed for specific emitter identification. First, multi‐level wavelet decomposition is performed on all received signals to obtain their wavelet detail coefficients at different scales. Next, all the wavelet detail coefficients are used as the feature input for the attention‐based residual network, and perform parallel feature extraction at multi scales. Finally, the feature representation capability of all coefficients are compared, and the model's recognition results based on it are obtained. The recognition rates on the three datasets are 94.7%, 93.21%, and 86.1%, respectively, all of which are superior to recent state‐of‐the‐art algorithms. In addition, through ablation experiment, the validity of each component of the model has been verified.
3D position and pose measurement based on coded light field
Authors: Liu Wei , Chang Ding , Shao Jiajun , Yang Yanxi
Published: June 2024

High‐precision relative position and attitude measurement technology has a wide range of applications in aerospace and industrial production. Currently, the commonly used method for measurement is based on visual cooperative signs. However, its accuracy significantly decreases as the distance increases. Therefore, a relative positioning system is designed based on light field spatial coding and visual recognition. The projector emits spatially encoded structured light within the coverage of the light field, while the receiving end captures, identifies, measures the code, and calculates its pose in the light field coordinate system. Compared with the traditional measurement method, the measurement accuracy of this system does not decrease greatly with the increase in distance, the measurement distance can be adjusted in real‐time and does not depend on an external light source. By changing the projection pattern with different resolutions without changing hardware systems, it can adjust effective measurement distance accordingly. Theoretical and experimental results show that the proposed method can maintain measurement accuracy with the increase in distance.
An Efficient Reconfigurable Transmitter with Anti-Offset Performance and High Compatibility for Vehicle-to-Vehicle (V2V) Wireless Charging Systems
Authors: Xie Ronghuan , Pan Wenbin , Wu Yuanchao , Shen Zhiwei , Li Zhongqi , Zhang Yiming
Published: June 2024

To solve the interoperability and anti-offset problems in vehicle-to-vehicle (V2V) wireless charging systems, a reconfigurable transmitter is proposed to adapt to unipolar and bipolar coils. By changing the circuit configuration, power transmits efficiently from one EV to the other. The proposed reconfigurable transmitter works in two modes. Moreover, the anti-offset performance of the proposed coil is improved by adding the anti-series windings. The system is verified by simulation to maintain stable output under different offsets, proving its effectiveness in solving the interoperability and offset problems for V2V wireless charging systems.
Power quality disturbance detection method based on optimized kernel extreme learning machine
Authors: Xu Lin , Zhao Chun , Guo Lisha , Xiong Jiayu , Liu Chang , Wang Zhuo , Wei Zhen , Liu Bo
Published: June 2024

In order to improve the accuracy of rapid detection of power quality, a power quality disturbance (PQD) classification method based on kernel-based extreme learning machine (KELM) is proposed, and chaos optimization is used to improve the global optimization performance of the particle swarm algorithm. This method first uses KELM to establish a classification model, and then uses an improved chaotic particle swarm optimization (CPSO) to optimize the parameters of KELM. Comparative analysis of example simulation results shows that the algorithm has higher classification accuracy and improves the reliability of power quality disturbance detection.
Verbot von Feuerwerkskörpern reduziert schwere Handverletzungen an
Silvester: Eine deutschlandweite Multicenter-Studie des Pyrotechnikverbots im
Rahmen der Covid-19-Maßnahmen
Authors: Demmer Wolfram , Mesas Aranda Irene , Jimenez-Frohn Marcela , Esser Tobias , Oeckenpöhler Simon , Lauer Henrik , Giunta Riccardo E , Haas-Lützenberger Elisabeth Maria
Published: June 2024

Hintergrund Verletzungen durch Explosionen oder pyrotechnische Ereignisse
können zu schwerwiegenden Handverletzungen führen, die teilweise langfristige
Auswirkungen sowohl für den Betroffenen als auch das Gesundheitssystem haben.
Bislang konnte die Einführung eines landesweiten Verbots von Feuerwerkskörpern
zum Jahreswechsel lediglich vorübergehend im Rahmen der Schutzmaßnahmen zur
Eindämmung der Covid-19-Pandemie umgesetzt werden. Diese zwei Ausnahmejahre
konnten im Sinne eines Modellversuchs ausgewertet werden, um aufzuzeigen,
welchen Effekt ein Verbot von Feuerwerk hinsichtlich Verletzungshäufigkeit von
Explosionsverletzungen bedeutet.

Material und Methoden Im Rahmen einer Multicenter-Studie haben fünf
deutsche Hand Traumazentren alle durch Feuerwerks- oder Knallkörper entstandenen
Verletzungen, die in einem Zeitraum von sieben Tagen um den Jahreswechsel
operativ versorgt wurden, retrospektiv erhoben und ausgewertet. Hierbei wurden
die Jahre 2017–2023 eingeschlossen.

Ergebnisse Schwere Handverletzungen durch Explosionen kamen während
geltender Covid-19 Schutzmaßnahmen signifikant seltener vor verglichen mit den
übrigen erhobenen Jahreswechseln. Nach Rückkehr zu regulären Verkaufsgesetzen
und Feierlichkeiten im Jahr 2022 konnte flächendeckend ein signifikanter
Wiederanstieg der Verletzungszahlen aufgezeigt werden, die sogar den
Vor-Covid-19-Zeitraum überstiegen. Die epidemiologischen Daten bestätigten einen
hohen Anteil an Minderjährigen und männlichen Patienten. Es kam zu einer Häufung
von schweren Verletzungen in der Neujahrsnacht und dem ersten Januar, wobei
Erwachsene sich vor allem zum Zeitpunkt der Feierlichkeiten, Kinder und
Jugendliche jedoch erst sekundär in den ersten Januartagen verletzten.

Schlussfolgerungen Nationale Verbote stellen eine effektive Methode dar,
um schwere Handverletzungen, ausgelöst durch Explosionskörper, und deren
lebenslange Folgen zu verhindern. Die in dieser Multicenter-Studie gewonnenen
Daten können als Bestandteil einer Grundlage für politisches Handeln dienen.
Safety of contrast-enhanced ultrasound using microbubbles in human pregnancy: A scoping review
Authors: Dassen Sophie , Monen Loes , Oei Guid , Mischi Massimo , van Laar Judith
Published: June 2024

Introduction Successful placentation is crucial for fetal development and maintaining a healthy pregnancy. Placental insufficiency can cause a variety of obstetric complications. Despite the many efforts to enhance diagnosing placental insufficiency, no imaging technique has proven satisfactory. A promising imaging technique is contrast-enhanced ultrasound (CEUS) using microbubbles which has proven capable of (micro)vascular imaging. Its use for placental vascularization assessment in human pregnancies remains constrained by limited evidence and safety concerns. This scoping review aims to demonstrate the safety of CEUS used in human pregnancy in the published literature to date.

Material and Methods A systematic search using PubMed, Medline, Embase, and Cochrane databases was performed. All studies where contrast-enhanced ultrasound was used in pregnant humans were included. Studies, where there was a planned termination of pregnancy, were excluded. To assess the safety of CEUS during pregnancy, relevant outcomes were divided into the following 3 categories; fetal outcome, maternal outcome, and pregnancy and neonatal outcomes.

Results A total of 13 articles were included, in which 256 women underwent CEUS during pregnancy. No clinically significant maternal or fetal adverse events or negative pregnancy or neonatal outcomes associated with CEUS were described.

Conclusion Based on our findings, we consider expanding the knowledge of this promising diagnostic technique in future larger clinical studies to be safe and relevant.
Attempts on Fluorinative Transformation of Selected Functionalized Cycloalkene Scaffolds through Aziridination/Aziridine-Opening Protocol
Authors: Nonn Melinda , Kiss Loránd , Novák Tamás T. , Gömöry Ágnes , Han Jianlin
Published: June 2024

Studies on the transformations of some functionalized cycloalkene derivatives through their ring olefin-bond aziridination/aziridine opening with fluoride are presented. The selected model compounds submitted to fluorinative functionalization were an amino ester and diesters with a cyclohexene skeleton as well as a cyclopentene-fused β-lactam. Functionalization proceeded across a substrate-directed diastereoselective olefin-bond aziridination, followed by fluoride-mediated aziridine opening or intramolecular lactonization giving some fluorinated amino ester or amino lactone derivatives.
On the Existence and Relevance of Copper(III) Fluorides in Oxidative Trifluoromethylation
Authors: Nebra Noel , Joven-Sancho Daniel
Published: June 2024

Numerous reports invoke CuIII–F intermediates engaging in oxidative cross-couplings mediated by low/mid-valent copper and formal sources of ‘F+’ oxidants. These elusive and typically instable CuIII fluorides have been rarely characterized or spectroscopically identified, making their existence and participation within catalytic cycles somehow questionable. We have authenticated a stable organocopper(III) fluoride that undergoes Csp–CF3 bond formation upon addition of silyl-capped alkynes following a 2 e– CuIII/CuI redox shuttle. This finding strongly supports the intermediacy of CuIII fluorides in C–C coupling. We review herein the state of the art about well-defined CuIII fluorides enabling cross-coupling reactions.

1 Introduction

2 Brief History of Coupling-Competent CuIII Fluorides

3 Design of an Isolable – yet Reactive – Organocopper(III) Fluoride

4 Alkyne Trifluoromethylation: Scope and Mechanism

5 Extension to Aryl–CF3 and C–Heteroatom Couplings

6 Summary and Outlook
An Indium(III) Triflate Catalyzed Simple and Efficient One-Pot Synthesis of Substituted 3,3-Diaryloxindoles and Bis(indol-3-yl) methanes from Indoles and Isatins or Aryl Aldehydes
Authors: Vandana Vemulapalli , Rao Narra Laxmana , Swamy Kolakaluri Chaguru , Alapati Mohan Lakshmi Punna Rao
Published: June 2024

Indium(III) triflate was found to be an efficient metal catalyst for the electrophilic substitution reaction of substituted indoles with various isatins or aryl aldehydes in acetonitrile solvent to afford the corresponding 3,3-diaryloxindoles or bis(indol-3-yl)methanes, respectively, in high yields at room temperature. This new procedure has remarkable features such as experimental simplicity, high conversions, good to excellent yields, short reaction times, and simple workup procedures
Comparative Efficacy of Intracuff 1% and 2% Alkalinized Lignocaine with Saline on Endotracheal Tube-Induced Hemodynamic Changes and Emergence Phenomena in Neurosurgical Patients
Authors: Mounisha Elugoti , Talwar Vandana , Mudgal Pratibha
Published: June 2024

Introduction Extubation is associated with hemodynamic changes and emergence phenomena leading to cough, sore throat, dysphonia, and dysphagia in the postoperative period. The aim of our study was to compare intracuff 2% alkalinized lignocaine with 1% alkalinized lignocaine and saline in reducing endotracheal tube induced emergence phenomena and haemodynamic changes at extubation in neurosurgical patients.

Materials and Methods In this randomized controlled study, 90 adult patients of either sex, scheduled to undergo neurosurgical procedures were randomly divided into three groups of 30 each to receive either 1% alkalinized lignocaine (AL1), 2% alkalinized lignocaine (AL2), or saline as cuff inflation media. Intracuff pressures and haemodynamic variables were noted intraoperatively and during emergence. The presence of postextubation cough, sore throat, dysphonia, and dysphagia were monitored until 24 hours postoperatively. Data were analyzed using Chi-square test and ANOVA. A p-value of less than 0.05 was considered significant.

Results The intracuff pressures were significantly less with alkalinized lignocaine as compared to saline, after 3 hours of induction. Post extubation, hemodynamic parameters and incidence of coughing and bucking at extubation were significantly less in Groups AL1 (p = 0.024) and AL2 (p = 0.02) as compared to saline. On assessment of laryngotracheal morbidity, the incidence of coughing was found to be significantly less with 2% alkalinized lignocaine as compared to saline (p = 0.021) at 1 hour after extubation. Sore throat was significantly less in Groups AL1 and AL2 as compared with saline at 1 hour (p = 0.008, 0.002 respectively) and 8 hours (p = 0.01 in both groups), and in Group AL2 versus saline at 24 hours (p = 0.044) after extubation. The incidence of dysphonia was significantly less in Groups AL1 and AL2 as compared with saline at 1 hour (p = 0.016, p = 0.002) and 24 hours (p = 0.012 in both groups) and in Group AL2 versus saline at 8 hours (p = 0.03) postoperatively. No significant differences were noted between 1% alkalinized lignocaine and 2% alkalinized lignocaine.

Conclusion Intracuff alkalinized lignocaine 1% and 2% were significantly better than saline in reducing coughing and bucking at extubation, post extubation haemodynamic changes and incidence of postoperative cough, sore throat, and dysphonia.
Network consumption and sports practice: influence on the risk of network addiction and basic psychological needs
Authors: Vega-Díaz Marta , González-García Higinio
Published: June 2024

The objective of the study was to identify the possibility of developing a risk of addiction to social networks and to know the satisfaction of basic psychological needs depending on network usage time, the number of networks used, and the practice hours and type of sport developed. A sample of 265 university students (Mage = 28.23; SD = 8.44; 110 men and 155 women) completed distinct self-report measures. Results revealed significant differences in the addiction-symptoms, social-use and geek-traits, being higher when the time of network consumption increases and when the number of networks used is bigger. Regarding the sports variables, collective sports are significantly associated with the risk of addiction symptoms. However, the practice of collective sports seems to satisfy basic psychological needs. In conclusion, the higher use and number of social networks seem to predict the risk of addiction to them. Single sports practice decreases the probability of network addiction and, collective and single sports help satisfy basic psychological needs.
Removing non-resonant background of CARS signal with generative adversarial network
Authors: Luo Ziyi , Xu Xiangcong , Lin Danying , Qu Junle , Lin Fangrui , Li Jia
Published: June 2024

Coherent anti-Stokes Raman scattering (CARS) microscopy requires the removal of non-resonant background (NRB) to ensure spectral accuracy and quality. This study introduces a deep-learning-based algorithm that leverages its enhanced capability for NRB removal and spectra retrieval. A generative adversarial network is trained using simulated noisy CARS data, enabling straightforward analysis of real CARS spectra obtained from pork belly and living mice brains. The results highlight the algorithm's ability to accurately extract vibrational information in the CH region. Importantly, this method eliminates the need for additional experimental measurements or extensive data preprocessing or postprocessing.
Unification of Ewald and shifted force methods to calculate Coulomb interactions in molecular simulations
Authors: Hammonds K. D. , Heyes D. M.
Published: June 2024

Three new Ewald series are derived using a new strategy that does not start with a proposed charge spreading function. Of these, the Ewald series produced using shifted potential interactions for the Ewald real space series converges relatively slowly, while the corresponding expression using a shifted force (SF) interaction does not converge. A comparison is made between several approximations of the Ewald method and the SF route to include Coulomb interactions in molecular dynamics (MD) computer simulations. MD simulations of a model bulk molten salt and water were carried out. The recently derived α′ variant of Ewald, by K. D. Hammonds and D. M. Heyes [J. Chem. Phys. 157, 074108 (2022)], has been developed analytically and found to be more accurate and computationally efficient than SF in part due to the smaller real space truncation distance that can be used. In addition, with α′, the number of reciprocal lattice vectors required is reduced considerably compared with the standard Ewald implementations to give the same accuracy. The invention of the α′ method shifts the computational balance back toward using an Ewald construction. The SF method shows greater errors in the Coulomb pressure and time dependent fluctuation properties compared to α′. It does not conserve the shadow Hamiltonian in a microcanonical MD simulation, whereas the α′ method does, which facilitates long time stability and insignificant drift of properties over time. The speed of the Ewald computer code is improved by using a new lookup table method.
Convection instability of linear Oldroyd-B fluids in a vertical channel with non-Fourier heat flux model
Authors: Sun Yanjun , Jia Beinan , Jian Yongjun
Published: June 2024

Owing to the importance of non-Fourier heat flux model in several natural and engineering processes, the convection of binary viscoelastic fluid in a vertical channel with non-Fourier heat flux model is investigated. The linear Oldroyd-B constitutive equation is used to model viscoelasticity. The presence of the basic flow in the vertical y-direction makes the problem challenging compared with the case in Rayleigh–Bénard convection. We use the Chebyshev collocation method to explore the instability characteristics of the linear Oldroyd-B fluid under a wide variety of physical parameters. Results show that the non-Fourier effect and relaxation time contribute to destabilize the system for oscillatory convection. The retardation time can inhibit the instability of the convective system. In the absence of the non-Fourier effect, the vertical fluid layer cannot support oscillatory motions. Oscillatory motion is possible, and the neutral stability curve branches when the non-Fourier effect is taken into account in the fluid. In addition, a new interesting phenomenon can be found: under the coupling action of viscoelastic fluids and the non-Fourier effect, the neutral stability curve would change from single to two branches and then to a single branch with the increase in relaxation time.
Free-surface air entrainment into bubbles by a Rushton-type impeller in unbaffled stirred tank
Authors: Sung Hyungyu , Park Hyungmin
Published: June 2024

While the bubbles generated through the free-surface air entrainment in an unbaffled stirred tank affect the dynamics of fluid mixing and gas exchange, their detailed mechanism and characteristics have not been investigated so far. In this study, we focus on analyzing the spatial distribution and the Sauter mean diameter of entrained bubbles by a Rushton-type impeller inside the tank, using high-speed shadowgraphy while varying the impeller rotation speed and geometrical parameters. It was mainly found that the air entrainment mechanism and evolution of entrained bubbles depend on the flow structure, which was identified by particle image velocimetry. Following the change from double- to single-loop vortical structures as the distance between the free-surface and impeller decreases, the role of free-surface instability becomes dominant in bubble entrainment. The impeller rotation speed also has a greater impact on the Sauter mean diameter of entrained bubbles compared to the double-loop regime. Based on the above, we classified the regimes and drew scaling relations for the Sauter mean diameter of entrained bubbles in terms of the geometrical and flow parameters, including the Weber number. Furthermore, it is shown that the turbulent kinetic energy is the primary contributor to the fragmentation of entrained bubbles inside the tank, following the theory of classical Kolmogorov–Hinze framework.
Turbulence–equation of state interaction modeling in large-eddy simulation at supercritical pressure conditions
Authors: Ghayour Amirmohammad , Salehi M. Mahdi
Published: June 2024

The development cost of high-pressure energy conversion systems can be substantially reduced by using predictive computational fluid dynamics simulation tools. Under such conditions, the non-linearity of the equation of state (EoS) increases, and one may be required to provide a closure model for the interaction between the EoS and the unresolved turbulence scales in large-eddy simulations (LESs). The use of such a model has been limited to a few previous studies, and it is largely ignored by most others. This study explores the need for a closure model under different thermo-hydrodynamic conditions. A presumed probability density function approach is used to provide a closure model for the filtered density field in a pressure-based LES solver. The simulation results compare very well with the experiments, both qualitatively and quantitatively. This closure model is then used to prescribe a regime diagram that determines the necessity of using this model under different injection conditions. Multiple LES runs were conducted, both with and without the closure model, under various injection conditions. The findings demonstrate the efficacy of the regime diagram in identifying the conditions necessitating turbulence–EoS interaction closure modeling. In general, using such a closure model is recommended for transcritical injection—where the injection temperature is less than the pseudo-boiling temperature of the supercritical fluid—even in highly resolved large-eddy simulation cases.
Coupled internal rotations and 14N quadrupole hyperfine structure of 2,4-dimethylpyrrole investigated by microwave spectroscopy and quantum chemistry
Authors: Barth Mike , Kleiner Isabelle , Nguyen Ha Vinh Lam
Published: June 2024

The microwave spectrum of 2,4-dimethylpyrrole was investigated using a Fourier-transform microwave spectrometer in a supersonic expansion. Torsional splittings arising from two inequivalent methyl internal rotors in combination with hyperfine splittings due to the nuclear quadrupole coupling of the 14N nucleus were observed. The experiments were accompanied by quantum chemical calculations. A total of 1561 rotational lines were assigned and fitted in global fits using the programs XIAM and BELGI-Cs-2Tops-hyperfine, both achieved the measurement accuracy of 4 kHz. Local separate fits were also performed to verify the correctness of the assignment. Accurate experimental molecular and internal rotation parameters could be deduced and compared to the calculated ones. The barrier to internal rotation of the 2-methyl rotor was determined to be 277.830(26) cm−1, essentially the same as the value of about 280 cm−1 found for 2-methylpyrrole but lower than the value of 317 cm−1 found for 2,5-dimethylpyrrole. The torsional barrier value of the 4-methyl rotor is 262.210(27) cm−1, slightly higher than the value of 246 cm−1 found for 3-methylpyrrole. Benchmarking the rotational constants for 2,4- and 2,5-dimethylpyrrole revealed that the MP2/6-31G(d,p) level could be helpful to guide the assignment of microwave spectra of pyrrole derivatives.
Magnetohydrodynamics flow and heat transfer of novel generalized Kelvin–Voigt viscoelastic nanofluids over a moving plate
Authors: Feng Libo , Liu Fawang , Turner Ian , Van Anh Vo
Published: June 2024

In this work, the unsteady magnetohydrodynamics boundary layer flow and heat transfer of novel generalized Kelvin–Voigt viscoelastic nanofluids over a moving plate are investigated. The classical Kelvin–Voigt constitutive relation is generalized to incorporate a time-fractional derivative to characterize the fluid behavior, which is proved to be of significance and physically justified. The newly developed fractional Kelvin–Voigt constitutive correlation and a dual-phase-lagging constitutive equation are applied to the momentum and energy equations, respectively, for a nanofluid model over a moving plate. The formulated integrodifferential velocity and thermal boundary layer equations are solved using the finite difference method together with a fast algorithm, which reduces the consumed central processing unit time significantly. Several numerical examples are presented to illustrate the influence of the critical parameters on the nanofluid motion and thermal characteristics. Compared to the fractional Maxwell nanofluid model, the velocity boundary layer for the fractional Kelvin–Voigt nanofluid model is thinner. Although the fractional indexes show similar effects on the velocity boundary layer, the impacts of the relaxation parameters are in contrast. This work provides valuable insights into the feasibility of using the fractional Kelvin–Voigt viscoelastic model to depict the fluid flow and heat transfer characteristics of nanofluids.
Influence of energy transfer processes on the rovibrational characteristics of CO2 in low-temperature conversion plasma with Ar and He admixture
Authors: Budde Maik , Engeln Richard
Published: June 2024

The influence of argon and helium on the rovibrational kinetics of carbon dioxide (CO2) and CO in low-temperature conversion plasma is investigated. With this objective, a combined experimental and computational study is conducted, applying quantum cascade laser infrared absorption spectroscopy to a pulsed DC CO2 glow discharge with varying noble gas admixture and modeling it with a two-term Boltzmann solver. Time-resolved rovibrational temperatures and dissociation fractions are presented, exhibiting an increase in rotational–vibrational non-equilibrium and an increasing CO2 conversion with argon (Ar) and helium (He) admixtures. Results are discussed in the context of energy transfer processes for collisions involving electrons, corroborated by electron-kinetic modeling, and heavy particle collisions. With noble gas addition, an increase in the electron number density, promoting excitation, and the high-energy tail of the electron energy distribution function are found. Penning ionization processes are proposed as an explanation for the increase in conversion, showing higher conversion for Ar due to the lower excitation thresholds and, therefore, larger state population. In the context of rovibrational kinetics, processes leading to the gain or loss of vibrational energy of CO2 are analyzed, pointing out subtle differences in, for example, relaxation rate coefficients between Ar and He. However, the cooling of the gas through conductive heat transfer is identified as the most important influence of the Ar and He admixture, as it keeps the relaxation rate for vibrational quenching low.
Centrifugal pump performance improvement using back cavity filling
Authors: Dokiparti Satish , Doshi Ashish , Bade Mukund Haribhau
Published: June 2024

Centrifugal pumps consume majority of energy used by the electric motor driven systems among all end users of the industrial sector. Only in European region, a 1% improvement in efficiency (η) of the centrifugal pump is capable enough to reduce CO2 emissions by at least 572 tons per day. The prime motive of this research is to assess the applicability of the novel back cavity filling (BCF) in reducing the disk friction losses of centrifugal pumps without changing the pump's original design. By adding a solid ring to the bearing housing's back-cover plate, the BCF was applied to a medium specific speed pump (Ns = 54 rpm), resulting in a 1 mm back axial clearance from 13 mm. Numerical simulations and experiments were carried out to investigate the effect of BCF on pump performance under two conditions: with and without BCF at best efficient point (BEP) and various partload conditions for 1450 rpm (rated) as well as 1000 rpm. Pump performance characteristics were enhanced by BCF at both rpms for the whole flow rate range. At 1450 rpm, BCF resulted in an average 0.74% increment in total head, 2.08% reduction in input torque, and 2.70% increment in overall efficiency over the flow rate range. While an average 2.04% improvement in total head, 1.33% reduction in input torque, a 3.30% enhancement in overall efficiency were obtained at 1000 rpm. Performance parameter enhancement was higher at lowest part load compared to the BEP on rated rpm.
Mode coupling behavior and fragile to strong transition of trehalose in a binary mixture with water upon supercooling
Authors: Lupi Laura , Gallo Paola
Published: June 2024

We perform molecular dynamics simulations of a binary mixture of water and trehalose with the TIP4P/Ice water model. We analyze the slow dynamics of trehalose molecules in the mildly supercooled region for concentrations of 3.66 and 18.57 wt. %. We previously studied the dynamics of water in the same mixtures. Supercooled TIP4P/Ice water solvating trehalose molecules was found to follow the Mode Coupling Theory (MCT) and to undergo a transition from a fragile to a strong behavior for both concentrations. Here, we show that also the dynamics of trehalose molecules follows the MCT and displays a fragile to strong crossover (FSC). The results show that trehalose in binary mixtures with water shares with it the dynamical behavior typical of glass forming liquids. Moreover, the FSC for trehalose structural relaxation times is found to occur at temperatures close to those previously obtained for water in the same solutions, showing that the dynamics of the solute is strongly coupled to that of the solvent. We also perform a MCT test showing that the trehalose dynamics obeys the MCT time–temperature superposition principle and that the exponents derived from the theory and the ones obtained from fitting procedure of the relaxation times are comparable, confirming that trehalose molecules in supercooled water solutions follow the MCT of glassy dynamics. Moreover, as predicted by the theory, trehalose particles have MCT parameters comparable to those of water in the same mixtures. This is an important result, given that MCT was originally formulated for monoatomic particles.
Learning dynamical systems from data: An introduction to physics-guided deep learning
Authors: Yu Rose , Wang Rui
Published: June 2024

Modeling complex physical dynamics is a fundamental task in science and engineering. Traditional physics-based models are first-principled, explainable, and sample-efficient. However, they often rely on strong modeling assumptions and expensive numerical integration, requiring significant computational resources and domain expertise. While deep learning (DL) provides efficient alternatives for modeling complex dynamics, they require a large amount of labeled training data. Furthermore, its predictions may disobey the governing physical laws and are difficult to interpret. Physics-guided DL aims to integrate first-principled physical knowledge into data-driven methods. It has the best of both worlds and is well equipped to better solve scientific problems. Recently, this field has gained great progress and has drawn considerable interest across discipline Here, we introduce the framework of physics-guided DL with a special emphasis on learning dynamical systems. We describe the learning pipeline and categorize state-of-the-art methods under this framework. We also offer our perspectives on the open challenges and emerging opportunities.
Hyperuniformity in phase ordering: the roles of activity, noise, and non-constant mobility
Authors: De Luca Filippo , Ma Xiao , Nardini Cesare , Cates Michael E
Published: June 2024

Hyperuniformity emerges generically in the coarsening regime of phase-separating fluids. Numerical studies of active and passive systems have shown that the structure factor S(q) behaves as q

ς
for q → 0, with hyperuniformity exponent ς = 4. For passive systems, this result was explained in 1991 by a qualitative scaling analysis of Tomita, exploiting isotropy at scales much larger than the coarsening length. Here we reconsider and extend Tomita’s argument to address cases of active phase separation and of non-constant mobility, again finding ς = 4. We further show that dynamical noise of variance

D

creates a transient ς = 2 regime for

q
^

≪

q
^

∗

∼

D

t

[
1
−
(
d
+
2
)
ν
]

/

2

, crossing over to ς = 4 at larger

q
^

. Here, ν is the coarsening exponent for the domain size

ℓ

, such that

ℓ
(
t
)
∼

t
ν

, and

q
^

∝
q
ℓ

is the rescaled wavenumber. In diffusive coarsening

ν
=
1

/

3

, so the rescaled crossover wavevector

q
^

∗

vanishes at large times when

d
⩾
2

. The slowness of this decay suggests a natural explanation for experiments that observe a long-lived ς = 2 scaling in phase-separating active fluids (where noise is typically large). Conversely, in d = 1, we demonstrate that with noise the ς = 2 regime survives as

t
→
∞

, with

q
^

∗

∼

D

5

/

6

. (The structure factor is not then determined by the zero-temperature fixed point.) We confirm our analytical predictions by numerical simulations of continuum theories for active and passive phase separation in the deterministic case and of Model B for the stochastic case. We also compare them with related findings for a system near an absorbing-state transition rather than undergoing phase separation. A central role is played throughout by the presence or absence of a conservation law for the centre of mass position R of the order parameter field.
A crosstalk-free multiple-image encryption scheme based on computational ghost imaging with binarized detection
Authors: Bai Xing , Yuan Sheng , Yu Zhan , Wang Yujie , Chen Xingyu , Liu Yang , Sun Mingze , Li Xinjia , Zhou Xin
Published: June 2024

Crosstalk noise is a main problem limiting the performance of multiple-image encryption (MIE) scheme. In this work, we proposed a crosstalk-free MIE scheme based on computational ghost imaging (CGI) with binarized detection. In the encryption process, the plaintext images are encrypted into intensity sequences by the CGI system and quantified into two levels to obtain binary ciphertext sequences, which does not cause severe degradation in decrypted image quality compared to traditional CGI. Then, for the binary ciphertext sequences, we can combine them into a decimal grayscale ciphertext. To enhance security, a pixel bit layer scrambling (PBLS) algorithm is designed to scramble the grayscale ciphertext to obtain the final ciphertext. In the decryption process, anyone of the plaintext images can be decrypted without being affected by other plaintext images after performing inverse PBLS algorithm on the ciphertext and extracting the binary ciphertext sequence. The effectiveness, robustness, encryption capacity and security of the proposed scheme are demonstrated by numerical simulations and theoretical analysis.
Scalar dark energy models and scalar–tensor gravity: theoretical explanations for the accelerated expansion of the present Universe
Authors: Ji Peixiang , Shao Lijing
Published: June 2024

The reason for the present accelerated expansion of the Universe stands as one of the most profound questions in the realm of science, with deep connections to both cosmology and fundamental physics. From a cosmological point of view, physical models aimed at elucidating the observed expansion can be categorized into two major classes: dark energy and modified gravity. We review various major approaches that employ a single scalar field to account for the accelerating phase of our present Universe. Dynamic system analysis was employed in several important models to find cosmological solutions that exhibit an accelerating phase as an attractor. For scalar field models of dark energy, we consistently focused on addressing challenges related to the fine-tuning and coincidence problems in cosmology, as well as exploring potential solutions to them. For scalar–tensor theories and their generalizations, we emphasize the importance of constraints on theoretical parameters to ensure overall consistency with experimental tests. Models or theories that could potentially explain the Hubble tension are also emphasized throughout this review.
Riemann–Hilbert problem for the defocusing Lakshmanan–Porsezian–Daniel equation with fully asymmetric nonzero boundary conditions
Authors: Ji 纪 Jianying 建英 , Xie 解 Xiyang 西阳
Published: June 2024

The Riemann–Hilbert approach is demonstrated to investigate the defocusing Lakshmanan–Porsezian–Daniel equation under fully asymmetric nonzero boundary conditions. In contrast to the symmetry case, this paper focuses on the branch points related to the scattering problem rather than using the Riemann surfaces. For the direct problem, we analyze the Jost solution of lax pairs and some properties of scattering matrix, including two kinds of symmetries. The inverse problem at branch points can be presented, corresponding to the associated Riemann–Hilbert. Moreover, we investigate the time evolution problem and estimate the value of solving the solutions by Jost function. For the inverse problem, we construct it as a Riemann–Hilbert problem and formulate the reconstruction formula for the defocusing Lakshmanan–Porsezian–Daniel equation. The solutions of the Riemann–Hilbert problem can be constructed by estimating the solutions. Finally, we work out the solutions under fully asymmetric nonzero boundary conditions precisely via utilizing the Sokhotski–Plemelj formula and the square of the negative column transformation with the assistance of Riemann surfaces. These results are valuable for understanding physical phenomena and developing further applications of optical problems.