bluuebunny/crossref_metadata_2025 huggingface dataset:
RNA fine-tunes estrogen receptor-alpha binding on low-affinity DNA motifs for transcriptional regulation
Authors: Soota Deepanshu , Saravanan Bharath , Mann Rajat , Kharbanda Tripti , Notani Dimple
Published: September 2024

Transcription factors (TFs) regulate gene expression by binding with varying strengths to DNA via their DNA-binding domain. Additionally, some TFs also interact with RNA, which modulates transcription factor binding to chromatin. However, whether RNA-mediated TF binding results in differential transcriptional outcomes remains unknown. In this study, we demonstrate that estrogen receptor α (ERα), a ligand-activated TF, interacts with RNA in a ligand-dependent manner. Defects in RNA binding lead to genome-wide loss of ERα recruitment, particularly at weaker ERα-motifs. Furthermore, ERα mobility in the nucleus increases in the absence of its RNA-binding capacity. Unexpectedly, this increased mobility coincides with robust polymerase loading and transcription of ERα-regulated genes that harbor low-strength motifs. However, highly stable binding of ERα on chromatin negatively impacts ligand-dependent transcription. Collectively, our results suggest that RNA interactions spatially confine ERα on low-affinity sites to fine-tune gene transcription.
Non-autophagic Golgi-LC3 lipidation facilitates TFE3 stress response against Golgi dysfunction
Authors: Kang Jaemin , Li Cathena Meiling , Kim Namhoon , Baek Jongyeon , Jung Yong-Keun
Published: September 2024

Lipidated ATG8/LC3 proteins are recruited to single membrane compartments as well as autophagosomes, supporting their functions. Although recent studies have shown that Golgi-LC3 lipidation follows Golgi damage, its molecular mechanism and function under Golgi stress remain unknown. Here, by combining DLK1 overexpression as a new strategy for induction of Golgi-specific LC3 lipidation, and the application of Golgi-damaging reagents, we unravel the mechanism and role of Golgi-LC3 lipidation. Upon DLK1 overexpression, LC3 is lipidated on the Golgi apparatus in an ATG12-ATG5-ATG16L1 complex-dependent manner; a post-Golgi trafficking blockade is the primary cause of this lipidation. During Golgi stress, ATG16L1 is recruited through its interaction with V-ATPase for Golgi-LC3 lipidation. After post-Golgi trafficking inhibition, TFE3, a key regulator of the Golgi stress response, is translocated to the nucleus. Defects in LC3 lipidation disrupt this translocation, leading to an attenuation of the Golgi stress response. Together, our results reveal the mechanism and unexplored function of Golgi-LC3 lipidation in the Golgi stress response.
Amplified centrosomes—more than just a threat
Authors: Kiermaier Eva , Stötzel Isabel , Schapfl Marina A , Villunger Andreas
Published: September 2024

Centrosomes are major organizing components of the tubulin-based cytoskeleton. In recent years, we have gained extensive knowledge about their structure, biogenesis, and function from single cells, cell–cell interactions to tissue homeostasis, including their role in human diseases. Centrosome abnormalities are linked to, among others primary microcephaly, birth defects, ciliopathies, and tumorigenesis. Centrosome amplification, a state where two or more centrosomes are present in the G1 phase of the cell cycle, correlates in cancer with karyotype alterations, clinical aggressiveness, and lymph node metastasis. However, amplified centrosomes also appear in healthy tissues and, independent of their established role, in multi-ciliation. One example is the liver where hepatocytes carry amplified centrosomes owing to whole-genome duplication events during organogenesis. More recently, amplified centrosomes have been found in neuronal progenitors and several cell types of hematopoietic origin in which they enhance cellular effector functions. These findings suggest that extra centrosomes do not necessarily pose a risk for genome integrity and are harnessed for physiological processes. Here, we compare established and emerging ‘non-canonical functions’ of amplified centrosomes in cancerous and somatic cells and discuss their role in cellular physiology.
Tissue-aware interpretation of genetic variants advances the etiology of rare diseases
Authors: Argov Chanan M , Shneyour Ariel , Jubran Juman , Sabag Eric , Mansbach Avigdor , Sepunaru Yair , Filtzer Emmi , Gruber Gil , Volozhinsky Miri , Yogev Yuval , Birk Ohad , Chalifa-Caspi Vered , Rokach Lior , Yeger-Lotem Esti
Published: September 2024

Pathogenic variants underlying Mendelian diseases often disrupt the normal physiology of a few tissues and organs. However, variant effect prediction tools that aim to identify pathogenic variants are typically oblivious to tissue contexts. Here we report a machine-learning framework, denoted “Tissue Risk Assessment of Causality by Expression for variants” (TRACEvar, https://netbio.bgu.ac.il/TRACEvar/), that offers two advancements. First, TRACEvar predicts pathogenic variants that disrupt the normal physiology of specific tissues. This was achieved by creating 14 tissue-specific models that were trained on over 14,000 variants and combined 84 attributes of genetic variants with 495 attributes derived from tissue omics. TRACEvar outperformed 10 well-established and tissue-oblivious variant effect prediction tools. Second, the resulting models are interpretable, thereby illuminating variants’ mode of action. Application of TRACEvar to variants of 52 rare-disease patients highlighted pathogenicity mechanisms and relevant disease processes. Lastly, the interpretation of all tissue models revealed that top-ranking determinants of pathogenicity included attributes of disease-affected tissues, particularly cellular process activities. Collectively, these results show that tissue contexts and interpretable machine-learning models can greatly enhance the etiology of rare diseases.
Characterization of Magnetic Nanoparticles for Magnetic Hyperthermia
Authors: Garaio E. , Rodrigo I.
Published: September 2024

This chapter is focused on different methods and experimental techniques intended to characterize nanoparticles designed for magnetic hyperthermia, a novel cancer therapy. Special attention is paid to the measurement of the specific absorption rate of magnetic nanoparticles, a key parameter that describes their ability to absorb energy from an externally applied magnetic field and then act as heat sources. This chapter starts by describing briefly the fundamentals of magnetic hyperthermia therapy and the role that magnetic nanoparticles and their specific absorptions play. Afterwards, the working principles of alternating (AC) magnetic field generators necessary to perform magnetic hyperthermia experiments are explained. Lastly, the two main methods, such as calorimetry and AC magnetometry, to characterize magnetic nanoparticles and measure their specific absorption are described and reviewed.
Utilizing solid-state nanopore sensing for high-efficiency and precise targeted localization in antiviral drug development
Authors: Xu Wei , Zou Lichun , Wang Haiyan , Xu Changhui , Fan Qinyang , Sha Jingjie
Published: September 2024

The efficient identification and validation of drug targets are paramount in drug discovery and development.
Advancing triage of acute lymphoblastic leukaemia subtypes diagnosis: label-free Raman spectroscopy for precise single-cell phenotyping and subtype classification
Authors: Leszczenko Patrycja , Nowakowska Anna M. , Dawiec Patrycja , Czuja Karolina , Jakubowska Justyna , Zabczynska Marta , Pastorczak Agata , Ostrowska Kinga , Tott Szymon , Mlynarski Wojciech , Baranska Malgorzata , Majzner Katarzyna
Published: September 2024

Acute lymphoblastic leukaemia (ALL) is a complex disease in pediatric oncology, necessitating accurate diagnostic strategies for effective treatment planning.
Hydrogen-bonding catalysis of the degradation of polyethylene glycol to 1,4-dioxane over OH-functionalized ionic liquid
Authors: Wang Huan , Zheng Xue , Wang Wei-Tao , He Zhen-Hong , Wang Kuan , Wang Weiping , Liu Jianchuan , Zhao Zhi-Hao , Liu Zhao-Tie
Published: September 2024

With the aid of theoretical computation, a novel hydrogen-bonding-catalyzed upcycling of polyethylene glycol waste to 1,4-dioxane over OH-functionalized ionic liquids under mild, solvent-, and metal-free conditions was designed and developed.
Mechanically interlocked host systems for ion-pair recognition
Authors: Arun Arya , Tay Hui Min , Beer Paul D.
Published: September 2024

This review details utilising mechanically interlocked host molecules containing cation and anion binding motifs to achieve ion-pair recognition.
High entropy alloy nanoparticles encapsulated into carbon nanotubes enable high performance of zinc air batteries
Authors: Pan Shuyuan , Shi Han , Yu Yingjie , Li Yifei , Chen Yazhou , Li Chunsheng , Sun Yan , Yang Zehui , Luo Fang
Published: September 2024

High entropy alloy nanoparticles encapsulated into nitrogen-doped carbon nanotubes show superior bifunctionality for the ORR and OER, evidenced by a battery performance of 214 mW cm−2, sustained for 200 h.
Porphyrins on acid: kinetics of the photoinduced-protonation of tetrakis(4-carboxyphenyl)-porphyrin
Authors: Prins P. Tim , Rutkowska-Zbik Dorota , Pullen Sonja , Baumgartner Bettina
Published: September 2024

Partial protonation of free-base porphyrins impacts their excited states, with implications for photocatalysis, studied via steady-state and nanosecond spectroscopy.
DFT and machine learning guided investigation into the design of new dual-atom catalysts based on α-2 graphyne
Authors: Chowdhury Chandra , Karthikraja Esackraj , Subramanian Venkatesan
Published: September 2024

This study employs machine learning to investigate the electrocatalytic properties of few dual-atom catalysts, examining critical aspects using SHAP values to improve comprehension of metal interactions and catalysts design.
Polytypic quantum wells in Si and Ge: impact of 2D hexagonal inclusions on electronic band structure
Authors: Marzegalli Anna , Montalenti Francesco , Scalise Emilio
Published: September 2024

This study reveals the impact of 2D hexagonal inclusions on Si and Ge, prompting their exploitation as light sources in Si photonics.
Sunlight-assisted synthesis of bimetallic silver–copper nanoparticles using peanut shell extract and its reusable activity against drug-resistant bacteria
Authors: Jayalakshmi S. , Singaravelu Dharshini Karnan , Mariappan Mariappan , Ameen Fuad , Veerappan Anbazhagan
Published: September 2024

Ag–Cu NPs combat drug-resistant bacteria and reusable.
Rapid diazotransfer for selective lysine labelling
Authors: Calvert Susannah H. , Pawlak Tomasz , Hessman Gary , McGouran Joanna F.
Published: September 2024

A rapid method to install azides into amino acids, peptides, and proteins, allowing for selective modification of a single lysine.
A multi-component synthetic route for 2-pyrazolines via acceptorless dehydrogenation of alcohols using homogeneous Ni(ii) catalysts
Authors: Kukreti Prashant , Chauhan Rahul , Panwar Abhishek , Ghosh Kaushik
Published: September 2024

Herein, we report the first multicomponent synthesis of pyrazolines from dehydrogenation of alcohols catalysed by pincer NNN-Ni(ii) catalysts.
Introduction to solar fuels and chemicals: photocatalytic water splitting and CO2 reduction themed collection
Authors: Abe Ryu , Ng Yun Hau , Ishitani Osamu , Domen Kazunari
Published: September 2024

Ryu Abe, Yun Hau Ng, Osamu Ishitani and Kazunari Domen introduce the Sustainable Energy & Fuels themed collection on Solar fuels and chemicals: photocatalytic water splitting and CO2 reduction.
Identifying mitigating strategies for endothelial cell dysfunction and hypertension in response to VEGF receptor inhibitors
Authors: Camarda Nicholas D. , Lu Qing , Meola Dawn M. , Man Joshua J. , Song Zeyuan , Travers Richard J. , Lopez Katherine E. , Powers Sarah N. , Papanastasiou Malvina , DeRuff Katherine C. , Mullahoo James , Egri Shawn B. , Davison Desiree , Sebastiani Paola , Eblen Scott T. , Buchsbaum Rachel , Huggins Gordon S. , London Cheryl A. , Jaffe Jacob D. , Upshaw Jenica N. , Yang Vicky K. , Jaffe Iris Z.
Published: September 2024

Vascular endothelial growth factor receptor inhibitors (VEGFRis) improve cancer survival but are associated with treatment-limiting hypertension, often attributed to endothelial cell (EC) dysfunction. Using phosphoproteomic profiling of VEGFRi-treated ECs, drugs were screened for mitigators of VEGFRi-induced EC dysfunction and validated in primary aortic ECs, mice, and canine cancer patients. VEGFRi treatment significantly raised systolic blood pressure (SBP) and increased markers of endothelial and renal dysfunction in mice and canine cancer patients. α-Adrenergic-antagonists were identified as drugs that most oppose the VEGFRi proteomic signature. Doxazosin, one such α-antagonist, prevented EC dysfunction in murine, canine, and human aortic ECs. In mice with sorafenib-induced-hypertension, doxazosin mitigated EC dysfunction but not hypertension or glomerular endotheliosis, while lisinopril mitigated hypertension and glomerular endotheliosis without impacting EC function. Hence, reversing EC dysfunction was insufficient to mitigate VEGFRi-induced-hypertension in this mouse model. Canine cancer patients with VEGFRi-induced-hypertension were randomized to doxazosin or lisinopril and both agents significantly decreased SBP. The canine clinical trial supports safety and efficacy of doxazosin and lisinopril as antihypertensives for VEGFRi-induced-hypertension and the potential of trials in canines with spontaneous cancer to accelerate translation. The overall findings demonstrate the utility of phosphoproteomics to identify EC-protective agents to mitigate cardio-oncology side effects.
Infrared surface brightness technique applied to RR Lyrae stars from the solar neighborhood
Authors: Zgirski Bartłomiej , Gieren Wolfgang , Pietrzyński Grzegorz , Górski Marek , Wielgórski Piotr , Storm Jesper , Bras Garance , Kervella Pierre , Nardetto Nicolas , Hajdu Gergely , Chini Rolf , Haas Martin
Published: September 2024

Context. The Baade-Wesselink (BW) method, also known as the pulsation parallax method, allows us to estimate distances to individual pulsating stars. Accurate geometric parallaxes obtained by the Gaia mission serve us in the calibration of the method and in the determination of its precision. This method also provides a way of determining mean radii of pulsating stars.

Aims. The main aim of this work is to determine the scatter and possible dependence of p-factors of RR Lyrae stars on their pulsation periods. The secondary objective is to determine the mean radius-period relations for these stars.

Methods. Our calibrations for RR Lyrae stars are based on photometric data gathered at the Cerro Murphy Observatory and parallaxes from the Data Release 3 of the Gaia space mission. We obtained spectroscopic data specifically for this project using high-resolution spectrographs. We used the infrared surface brightness (IRSB) version of the method that relies on a surface brightness-color relation that is dependent on the (V − K) color. It allows us to estimate stellar angular diameters, while tracing variations of the stellar radius using measurements of the stellar radial velocity obtained from spectroscopy. We present results based on four different empirical surface brightness-color relations, with three relations for dwarfs and subgiants and one for classical Cepheids.

Results. We present our calibration of projection factors and determination of the mean radii for nine Galactic RR Lyrae stars. We obtained a spread of p-factors of around 0.07–0.08 for our sample of RR Lyrae stars from the solar neighborhood. However, depending on a given SBCR, we also found relations between the p-factor and the pulsation period for RRab stars with a root mean square (rms) scatter around the relation of around 0.05, but with relatively large uncertainty on the relation parameters. We also present relations between the mean radius and period for RR Lyrae pulsating in the fundamental mode with an rms scatter around the relation of 0.012 R⊙. We observe a clear offset between p-factors obtained using the IRSB technique (with a mean p value between 1.39 and 1.45) and values inferred using the SPIPS tool. This confirms that different implementations of the BW method are sensitive to various components of the p-factor. On the other hand, we obtain a similar scatter for p, as observed in a previous study based on the SPIPS tool. Our period-radius relations are in a good agreement with both the inference based on SPIPS and theoretical predictions.
Reconstruction of Voronoi diagrams in inverse potential problems
Authors: Birgin Ernesto G. , Laurain Antoine , Souza Danilo R.
Published: September 2024

In this paper we propose and analyze a numerical method for the recovery of a piecewise constant parameter with multiple phases in the inverse potential problem. The potential is assumed to be constant in each phase, and the phases are modeled by a Voronoi diagram generated by a set of sites, which are used as control parameters. We first reformulate the inverse problem as an optimization problem with respect to the position of the sites. Combining techniques of non-smooth shape calculus and sensitivity of Voronoi diagrams, we are able to compute the gradient of the cost function, under standard non-degeneracy conditions of the diagram. We provide two different formulas for the gradient, a volumetric and an interface one, which are compared in numerical experiments. We provide several numerical experiments to investigate the dependence of the reconstruction on the problem parameters, such as noise, number of sites and initialization.
Driving factors on corporate green investments behaviors: from the strategic intersection of governments regulation and public participation
Authors: Jiang Ke , Xu Liping , Chen Xueqing , Ge Yuchen
Published: September 2024

As the global community confronts the challenges of climate change, businesses face increasing pressure to adopt sustainable practices. This study develops a tripartite game model to investigate the impact of green investments on corporate performance, considering the dynamic interplay between governments regulations and public participation in shaping strategic initiatives. First, the evolutionary stability strategy (ESS) is identified by solving replicator dynamic equations and performing stability analysis of equilibrium points. Next, the practicability and rationality of the evolutionary game model are assessed by analyzing ESSs under various corporate green investment scenarios. Finally, a case-based example is provided to validate the theoretical findings and support the following arguments: there are eight equilibrium points and four potential ESSs in the game model; the selection of each ESS is primarily determined by the trade-off between costs and revenues for each stakeholder; increased governmental regulatory costs prompt a strategic shift, incentivizing corporations to enhance green investments; while rising penalties drive a preference for green options; and corporations recognizing compensatory responsibilities are steered towards sustainable pathways.
Integrating the triple bottom line of sustainability, resilience strategies, and product perishability consideration to design a pharmaceutical supply chain network: a COVID-19 case study
Authors: Roshani Alireza , Gholamian Mohammad Reza , Arabi Mahsa
Published: September 2024

This paper aims to design a resilient and sustainable pharmaceutical supply chain network under the perishability of medicine in which a multi-objective nonlinear mathematical model is formulated. To this end, four objective functions seek to minimize total cost, maximize the social indicators, minimize CO2 emission and minimize de-resilience measures. Moreover, the three main categories of resilience strategies are integrated to mitigate the severe impacts of disruption. In order to solve the model, lexicographic goal programming is applied for small-scale problems, and NSGA-II is utilized for large-scale problems. The applicability of the proposed model is demonstrated by implementing it in a real case study during the COVID-19 situation. Also, a set of sensitivity analyses is conducted to validate the model and show the behavior of the objective functions. The results reveal the superiority of the resilient model with integrated strategies. Eventually, the Pareto front solutions are provided to quantify the trade-offs in satisfying the conflicting objective functions.
Degree conditions for path-factors in graphs
Authors: Zhang Ping
Published: September 2024

A spanning subgraph H of a graph G is called a path-factor if every component of H is a path. Wang and Zhang [RAIRO:RO 57 (2023) 2231–2237] conjectured that a connected graph G with δ(G) ≥ 5 contains a {P2, P5}-factor if δ(G)≥3α(G)−14, where δ(G) and α(G) denote the minimum degree and independence number of G, respectively. We show that the conjecture is true except G ≅ X ∨ 7K3, where X is a spanning subgraph of K3. Furthermore, we give two degree conditions for the existence of {P2, P5}-factors, one of which is a stronger version of Wang’s another conjecture. We also show the degree conditions are best possible.
Theoretical insights into oxygen reduction reaction on Au-based single-atom alloy cluster catalysts
Authors: Pu Yixuan , Liu Jin-Xun
Published: September 2024

Developing highly active alloy catalysts that surpass the performance of platinum group metals in the oxygen reduction reaction (ORR) is critical in electrocatalysis. Gold-based single-atom alloy (AuSAA) clusters are gaining recognition as promising alternatives due to their potential for high activity. However, enhancing its activity of AuSAA clusters remains challenging due to limited insights into its actual active site in alkaline environments. Herein, we studied a variety of Au54M1 SAA cluster catalysts and revealed the operando formed MOx(OH)y complex acts as the crucial active site for catalyzing the ORR under the basic solution condition. The observed volcano plot indicates that Au54Co1, Au54M1, and Au54Ru1 clusters can be the optimal Au54M1 SAA cluster catalysts for the ORR. Our findings offer new insights into the actual active sites of AuSAA cluster catalysts, which will inform rational catalyst design in experimental settings.
Three-dimensional transient modeling and simulation of high-current multi-component vacuum arc under transverse magnetic field
Authors: Xie Yiduo , Wang Lijun , Chen Jieli , Wang Xiangyu
Published: September 2024

This paper established a three-dimensional transient MHD model of a high-current multi-component vacuum arc under a transverse magnetic field (TMF) to simulate the dynamic characteristics of plasma parameters in the uniform motion mode of a contracted arc under lower TMF. The model considered the ionization–recombination process among the multi-components and used the P1 model to calculate the thermal radiation losses. The simulation results show that the ion number density of The TMF arc is on the order 1024 m−3, and when the plasma temperature reaches 4.3 eV, the effects of thermal radiation cannot be ignored. The majority of the plasma from the cathode and anode undergo acceleration and then deceleration before finally intersecting at the center of the arc, creating an extreme value of the density and the pressure, where a large amount of kinetic energy is converted into internal energy. The arc will be bent and deflected under the action of the ampere force, and the deflection of Cu3+ is especially obvious. The TMF affects the collision strength of the jet in the intersection area and, thus, affects the ion density, in which the change of Cu2+ is dominant. The ionization–recombination process of ions is mainly determined by the electron temperature, which is affected by the arc current. As the current decreases, Cu1+ increases and Cu2+ and Cu3+ decrease, and the change in ionization rate is the main reason for the change in the proportion of each ionic component; the heat flux density to the anode and cathode is on the order of 1010 W/m2, which heats the front of the arc and ensures the stable movement of the arc. Meanwhile, due to the high ion number density, the ion heat flux accounts for the main part of the heat flux, and the anode exhibits a higher proportion of ion heat flux.
Experimental demonstration of transition from J × B heating to stochastic heating in ultrashort high intensity laser foil interaction
Authors: Mandal T. , Arora V. , Moorti A. , Uphadhyay A. , Chakera J. A.
Published: September 2024

We experimentally demonstrate the transition of fast electron generation mechanism from J × B heating to stochastic heating by varying preplasma scale length in the interaction of ultrashort (∼25 fs) high intensity (∼3–4 × 1019 W/cm2) laser with thin foil. At sharp plasma density laser interaction (contrast ∼2 × 10−10 at 1 ns, L/λ ≪ 1), fast electrons were observed along the laser propagation direction demonstrating J × B heating. Interestingly, fast electron temperature in this case was less than ponderomotive scaling. The reasons were identified to be the small excursion length of electron compared to laser wavelength in sharp density interaction along with energy loss while escaping through the rear surface. A simplistic model has been proposed to understand the energy loss mechanism from the rear surface. Next, preplasma was introduced gradually by varying the amplified spontaneous emission contrast and additional picosecond prepulse at different delays. It resulted in an increase in the energy and temperature of fast electrons. Most importantly, at larger scale length (L/λ ≫ 1), fast electron temperature beyond the ponderomotive limit was observed. The temperature scales with scale length as T∝L0.59 and shows a saturation effect at longer scale length. The results indicate a gradual change in the fast electron generation mechanism to stochastic heating producing superponderomotive energy. Particle-in-cell simulation also very well reproduces our experimental findings.
Shear-flow driven ion-acoustic instability in a non-thermal magnetoplasma
Authors: Zafar A. , Ali S. , Aman-ur-Rehman
Published: September 2024

Relying on the kinetic model, we study linear properties of ion-acoustic waves in a non-thermal magnetoplasma, whose constituents are the electrons and singly charged positive ions. For this purpose, we solve a set of coupled Vlasov–Poisson equations within the framework of an unperturbed orbit theory and Fourier transformations. A generalized dielectric function is derived in a Cairns distributed plasma to investigate the electrostatic ion-acoustic waves with weak ion shear flows and ion streaming effects. It is found that the magnitude of the growth rate of the wave increases by varying the non-thermality and ion shear flow parameters. Furthermore, the wave spectrum and instability involving the ion-acoustic waves are analyzed with different plasma parameters in a non-thermal plasma. The present findings also reveal both analytical and numerical analyses of the electrostatic waves in the upper ionosphere, where non-thermal plasma particles are common.
Numerical simulation of dynamics behavior of pre-ionized pulsed-DC helium plasma jets at atmospheric pressure
Authors: Liu Yinghua , Yin Peiqi , Xu Boping , Liu Dawei , Pi Liangwen , Fu Yuxi , Wang Yishan , Zhao Wei , Tang Jie
Published: September 2024

A two-dimensional axisymmetric fluid model was established to investigate the dynamic behavior of pre-ionized pulsed-direct-current helium plasma jets at atmospheric pressure. Our simulation results show that, at a relatively low pre-ionization level, the electron number density is reduced and the streamer propagation is decelerated before the plasma jet is ejected from the tube, which is attributed to the inhibitory effect of a recombination process between the positive ions in the streamer and the seed electrons near the anode. As the pre-ionization reaches a relatively high level, the electron number density is larger than that without pre-ionization before the plasma jet is ejected from the tube, which originates from the promotion effect of decreased breakdown voltage. These two competing mechanisms jointly dominate the dynamic behavior of gas discharge in the presence of pre-ionization. After the plasma jet is ejected from the tube, the enhanced discharge power is responsible for the strengthened electric field in the streamer head, augmented total ionization rate, accelerated streamer propagation, and increased number density of electrons and active species, whatever the pre-ionization density is. With the increase in pre-ionization density, the plasma jet length, streamer propagation speed, discharge power, and discharge energy exhibit the initial increase and subsequent decrease variation trend. The optimal enhancement effect is obtained at the pre-ionization density of 6 × 1012 m−3, with the plasma jet lengthened by 28.4% and the energy deposition efficiency enhanced by 28.1%.
A versatile steel belt casting equipment for in situ synchrotron radiation x-ray scattering measurement of polymer films
Authors: Liu Shenghui , Cheng Shichao , Luo Yu , Zhu Jianhe , Liu Liangbao , Guo Hang , Cui Kunpeng , An Minfang , Li Liangbin
Published: September 2024

A steel belt casting equipment, weighing approximately ∼6–7 tons and measuring ∼5 m in length, has been designed and developed for simulating the industrial processing of polymer films and being combined with synchrotron radiation in situ x-ray scattering measurements. Through modification of its modules, it is feasible to implement two distinct film casting modes, namely the wet and the dry casting processes. The speed of a steel belt can span from 0.5 to 8 m/min. The highest experimental temperature and drying wind speed are 300 °C and 6 m/s, respectively. All film casting parameters, such as extrusion speed, distance between die and steel belt, casting speed, temperature, and wind speed, can be adjusted independently. Especially, the control accuracy of the temperature and casting rate can reach ±0.1 °C and ±0.01 m/min, respectively. The feasibility of this equipment has been validated through in situ x-ray scattering tests at the BL10U1 industrial beamline of the Shanghai synchrotron radiation facility. With the assistance of this equipment, the understanding of the physical mechanism behind the film casting process should be improved so that the development of advanced functional polymer films.
Study on the generation of terahertz waves in collision plasma
Authors: Bao Yu , He Xiang , Su Wei , Chen Jianping , Chen Yudong , Zeng Xiaojun , Gu Tingting
Published: September 2024

Terahertz communication technology holds promise for solving the challenging “blackout” problem. Research has revealed that the spectrum exhibits new peaks when terahertz waves propagate through plasma. In the realm of communications, elucidating the underlying physical mechanisms responsible for these novel peaks is of paramount importance. In this paper, a combination of theoretical analysis and simulation is utilized to investigate the causes of these spectral changes. Theoretically, the expression for the relative dielectric constant of plasma has been refined by incorporating collision terms. Drawing on radiation theory, a particle whose motion is interrupted by collisions can be considered equivalent to a damped harmonic oscillator. Thus, the frequency expression of the new peak was derived. Furthermore, the simulation involved the interaction of a terahertz wave, which had a frequency of 1 THz and lasted for 2 ps, and plasma characterized by a central electron density of 1021 m−3 and a collision frequency of 0.114 THz. The simulation results are consistent with the frequency expression of the new peak. In sum, this study found that collisions between electrons and neutral particles within plasma cause a shift in the frequency of terahertz waves, and has derived the frequency expression. This plasma model can be used to estimate the frequency range of terahertz waves that are generated as they propagate through collisional plasmas.
Microcanonical Monte Carlo of Lennard-Jones microclusters
Authors: Lustig Rolf
Published: September 2024

A novel statistical mechanical methodology is applied to clusters of N ≤ 7 atoms. Exact statistical analogs for any energy derivative of entropy ∂mS/∂Em are used in rigorous microcanonical Monte Carlo simulations to vastly enlarge the pool of measurable thermodynamic properties relative to previous work. All analogs are given for two alternative partition functions of the microcanonical ensemble. Coarse grained energy distributions are used to establish the existence of melting transitions. LJ7, LJ5, and LJ4 are found to exhibit trimodal distributions, a feature not being reported before. Varieties of combinations of entropy derivatives are tested for a direct detection of the melting region. It is shown that for such a purpose, derivatives of at least fourth order are necessary.
Investigation in the bag breakup of water droplet in airflow with different temperatures and densities
Authors: Zheng Ke , Gan Zhiwen
Published: September 2024

This paper tries to clarify the respective significance of thermal effects and airflow density on the influence of bag breakup of water droplets in hot airflow. The bag breakup processes of water droplets in the airflow temperature range of 293 K (ρg=1.205 kg/m3) to 493 K (ρg=0.716 kg/m3) were investigated. Meanwhile, room-temperature gas mixtures with corresponding densities were prepared using room-temperature helium blended with room-temperature air to explore the bag breakup processes of water droplets. The results show that although the critical conventional Weber number (Wecon) of spherical droplets for bag breakup varies significantly in both streams, the critical initiation Weber number (Weini) of disk-shaped droplets for bag breakup remains almost consistent. Different deformation processes from Wecon to Weini result in different Wecon. In the gas mixtures with room temperature, the critical Wecon for bag breakup increases from 9.47 to 12.12 as the stream density decreases from 1.205 to 0.716 kg/m3. However, the critical Wecon for bag breakup decreases from 9.47 to 7.80 in the hot airflow at identical airflow density variations.
Deep learning-aided active subspace exploration of free-stream effects for fan-shaped film cooling
Authors: Cai Feixue , Zhou Hua , Chen Fan , Yao Min , Ren Zhuyin
Published: September 2024

Film cooling plays a critical role in protecting engine components from high temperatures that can influence safety and performance of gas turbines. However, the process is fraught with uncertainties due to complex inflow conditions and geometrical configurations. These uncertainties significantly impact cooling effectiveness, underscoring the importance of identifying the dominant factors in a quantified manner. Traditional methods, such as the Monte Carlo approach, encounter the “curse of dimensionality,” making them computationally intensive as the number of variable increases. This study tackles these challenges by employing a deep learning strategy with a convolutional neural network (CNN) model to predict film cooling effectiveness efficiently, reducing computational loads compared to traditional computational fluid dynamics (CFD) simulations. It enables the CNN model to act as a surrogate for the CFD simulation and provides gradient information for subsequent analyses. Additionally, this study employs active subspace (AS) analysis for dimensionality reduction, identifying dominant parameters based on the trained CNN model. This approach not only enhances the speed of simulations but also provides an effective way to analyze dominant parameters and carry out optimizations. Results demonstrate a strong correlation between the CNN predictions and detailed CFD simulations, with all the mean absolute errors below 0.08, validating the model's efficacy in capturing complex cooling dynamics. The dominant analysis based on the AS method gives the blowing ratio as the most important factors, and the subsequent parameter dimension reduction and suggested optimization region are also explored by applying the low-dimensional active variable. The tested optimal factors yield higher spatially averaged cooling effectiveness above 0.35 and show reasonable pattern changes compared to the maximum and minimum results in the sample.
Fast characterization of multiplexed single-electron pumps with machine learning
Authors: Schoinas N. , Rath Y. , Norimoto S. , Xie W. , See P. , Griffiths J. P. , Chen C. , Ritchie D. A. , Kataoka M. , Rossi A. , Rungger I.
Published: September 2024

We present an efficient machine learning based automated framework for the fast tuning of single-electron pump devices into current quantization regimes. It uses a sparse measurement approach based on an iterative active learning algorithm to take targeted measurements in the gate voltage parameter space. When compared to conventional parameter scans, our automated framework allows us to decrease the number of measurement points by about an order of magnitude. This corresponds to an eightfold decrease in the time required to determine quantization errors, which are estimated via an exponential extrapolation of the first current plateau embedded into the algorithm. We show the robustness of the framework by characterizing 28 individual devices arranged in a GaAs/AlGaAs multiplexer array, which we use to identify a subset of devices suitable for parallel operation at communal gate voltages. The method opens up the possibility to efficiently scale the characterization of such multiplexed devices to a large number of pumps.
Aerodynamic characteristics of the train under real wind gust
Authors: Xue Ru-Dai , Chen Guang , Xiong Xiao-Hui
Published: September 2024

Research on aerodynamic loads and flow field characteristics of trains under real wind gust is limited. Most studies focus on train's dynamics under wind gust. By using numerical simulation methods to model the spatiotemporal evolution of the flow field around the train under real wind gust, the aerodynamic load and flow field characteristics of the train were studied. The one-minus-cosine wind gust model was adopted to achieve the real wind gust and the improved delayed detached eddy simulation based on shear stress transport k–ω turbulence model was used to perform numerical simulations of train operation under wind gust by applying the specified wind gust model function to the velocity inlet boundary. During the wind gust, the peak values for most of the aerodynamic loads of the train cannot reach the levels corresponding to those under constant crosswind, since the flow field around the train cannot fully develop into a stable flow field akin to that under constant crosswind. Compared to the wind gust without zero-crossing, the differences between unsteady and quasi-steady peaks are greater for side force, rolling moment, and yaw moment under wind gust with zero-crossing. This study addresses the gap in research on train aerodynamics under real wind gust conditions, providing essential data for train dynamics and a theoretical foundation for the safe operation of the train.
Exploring cavitation dynamics and noise reduction in hydraulic machinery with bionic leading edge impeller
Authors: Zhang Jinsong , Xi Wenqian , Tang Jiaxian , Huang Zhenwei
Published: September 2024

Cavitation and induced noise are common issues in the operation of mixed-flow pumps, affecting their stability. Studying these phenomena is of both academic and engineering interest. Previous research has mainly focused on modifying the impeller blade profile or optimizing the pump structure to reduce cavitation and noise. In this paper, we apply a bionic design to the mixed-flow pump impeller by mimicking the natural shape of a humpback whale's pectoral fin on the leading edge of the blade. We compare the cavitation suppression and noise reduction effects of this design with those of a conventional mixed-flow pump. Unsteady flow calculations for the original pump at different flow rates revealed that at its rated speed, increasing flow rates led to lower pressure in the low-pressure region on the suction surface of the impeller, expanding the cavitation-prone area. By applying the bionic design, we studied the unsteady cavitation flow and its induced noise. Results showed that the impeller and guide vane experienced larger pressure pulsations at the rotation frequency and its multiples. The bionic modification increased the cavitation initiation speed and reduced the cavity volume within the runner. With an NPSH (net positive suction head) of 6.76, the void volume in the bionic pump was only 79% of that in the original pump, and the head increased by 16%. Additionally, the bionic design reduced the maximum far-field sound pressure level by 12.5%, achieving significant noise reduction. This study demonstrates that the bionic design effectively controls dynamic flow separation, reduces flow-induced noise, and enhances the mixed-flow pump's performance. These findings have important theoretical and practical implications for optimizing mixed-flow pump design, improving energy efficiency, and reducing noise.
A planar plume array emanating from an atmospheric pressure argon plasma jet employing floating electrodes
Authors: Wu Kaiyue , Chen Mo , Ran Junxia , Jia Pengying , Wu Jiacun , Li Xuechen
Published: September 2024

Large-scale plasma plumes downstream of plasma jets are in urgent need from a practical viewpoint. In this Letter, an argon plasma jet with floating electrodes is proposed to produce a large-scale planar plume array. Results indicate that with increasing peak voltage (Vp), the planar plume array elongates gradually and scales up in the lateral direction to an optimal value of 90.0 mm. There is only one discharge pulse per voltage half cycle, whose intensity and duration increase with increasing Vp. Moreover, there is a time lag between the initiations of individual plumes. Fast photography reveals that the planar plume array originates from the repeated process of some micro-discharge filaments stretching along the argon stream. By optical emission spectroscopy, the spatial distribution of plasma parameters is obtained, such as electron density, electron temperature, and gas temperature. At last, the planar plume array is employed to test the surface modification of polyethylene terephthalate, for which a uniform modification has been realized with a scan velocity of 1.0 cm/min. These results are of great significance for the development of large-scale atmospheric pressure plasma sources.
Compact metal nano-powder generator of 273 MW average power and synthesis of copper nano-powder
Authors: Dubey A. K. , Shukla R. , Sagar K. , Dey P. , Sharma A.
Published: September 2024

The synthesis of metal nanoparticles holds significant promise for various applications ranging from electronics to catalysis. Their high specific surface area makes them more applicable in the form of lubricant and sorbent. Some of the metal nano-powders, such as silver, copper, and zinc, possess anti-microbial properties; hence, they are very useful in medical sciences. This paper presents a novel approach to the design and implementation of a compact metal nano-powder generator of 273 MW average power through the electrical explosion of wire method. The design focuses on achieving the automatic and repetitive operation of a compact metal nano-powder generator and minimizing its geometric inductance to achieve a fast rise time current across the exploding wire load. Copper nano-powder is produced with a copper wire of 450 μm thickness and 30 mm length at charging voltages of 8.5, 9.0, and 9.5 kV and achieving a superheat of 1.75, 1.92, and 2.06, respectively. The synthesis process is characterized by a detailed analysis of the copper nano-powder’s structural, morphological, and chemical composition using techniques such as x-ray diffraction, scanning electron microscopy, and energy-dispersive x-ray spectroscopy. The particle size distribution studies are performed by adopting the log-normal probability distribution. The results demonstrate the effectiveness of the proposed compact nano-powder generator in producing copper nano-powder with tailored properties suitable for diverse applications.
Modeling and scaling of cavitation compliance in Venturi
Authors: Yi Qihao , Zhang Haochen , Zuo Zhigang , Liu Shuhong
Published: September 2024

Understanding cavitation compliance in Venturi is important for research on system oscillations in fluid machinery, which describes the responsiveness of the cavity size to alternating inflow parameters. To consider both Venturi geometries and inflow conditions in evaluating the cavitation compliance, the cavitation region is modeled as a large vapor bubble, based on the experimental characteristics of the attached cavity characterizing the cavity size. Steady-state numerical solutions of cavity sizes show the influencing trends by geometrical and inflow parameters consistent with experiments. According to the analytical solution approximating the numerical solution, effective cavitation number σe and effective length ratio L̃* are defined to unify these influencing parameters. Based on the causes of cavitation pressure drops at the throat indicated by σe, cavitation compliance can be categorized into two regimes. Regime I features a smaller σe, and the dynamic pressure dominates in the pressure drops, theoretically resulting in L̃*∝σe−9. Regime II features a larger σe, and the bend-flow inertia and dynamic pressure are comparable, resulting in L̃*∝σe−2 in contrast. The power-law predictions of cavitation compliance are validated by experiments and literature.
Study on fluid dynamic lubrication numerical analysis and surface topography design of slipper pair of valve distribution piston pump
Authors: Zhao Kaiping , He Tao , Wang Chuanli , Luo Gang , Zheng Hao
Published: September 2024

In order to improve the fluid dynamic lubrication performance of slipper pair of valve distribution (digital distribution) axial piston pump, this paper proposes a theory analytical model of fluid dynamic lubrication for slipper pairs with different surface structures of valve distribution pump and its tribological optimization mechanism of surface microstructure topography. In the model, based on the finite volume method, the least square method combined with the trust region dogleg was proposed to solve the nonlinear system of equations of slipper dynamic balance. The fluid lubrication mechanism of slipper pairs with different surface structures was analyzed, the probability of overturning and eccentric wear of slipper pairs with complex surface structure and the viscous friction torque were quantitatively analyzed, and experimental research was conducted. The results show that the surface microstructure topography has great influence on the fluid lubrication performance of slipper pairs. Compared with before optimization, the friction torque of slipper with single-support belt, double-support belt, and four-support belt is decreased by 8.58%, 13.65%, and 17.07% at most, respectively, but the probability of overturning and eccentric wear of slipper with double-support belt and four-support belt is increased and the oil film becomes thicker. Reducing the friction loss and enhancing the anti-overturning ability of the slipper pair are often difficult to be compatible. The research results lay a theoretical and technical foundation for the optimization of lubrication performance of slipper pair of valve distribution pump.