bluuebunny/crossref_metadata_2025 huggingface dataset:
Resonant Auger decay of dissociating CH3I near the I 4d threshold
Authors: Pratt Stephen T. , Jacovella Ugo , Gans Bérenger , Bozek John D. , Holland David M. P.
Published: February 2024

Resonant Auger processes provide a unique perspective on electronic interactions and excited vibrational and electronic states of molecular ions. Here, new data are presented on the resonant Auger decay of excited CH3I in the region just below the I 4d−1 ionization threshold. The resonances include the Rydberg series converging to the five spin–orbit and ligand-field split CH3I (I 4d−1) thresholds, as well as resonances corresponding to excitation from the I 4d5/2,3/2 orbitals into the σ* lowest unoccupied molecular orbital. This study focuses on participator decay that populates the lowest lying states of CH3I+, in particular, the X̃2E3/2 and 2E1/2 states, and on spectator decay that populates the lowest-lying (CH3I2+)σ* states of CH3I+. The CH3I (I 4d−1)σ* resonances are broad, and dissociation to CH3 + I competes with the autoionization of the core-excited states. Auger decay as the molecule dissociates produces a photoelectron spectrum with a long progression (up to v3+ ∼ 25) in the C–I stretching mode of the X̃2E3/2 and 2E1/2 states, providing insights into the shape of the dissociative core-excited surface. The observed spectator decay processes indicate that CH3I+ is formed on the repulsive wall of the lower-lying (CH3I2+)σ* potentials, and the photon-energy dependence of the processes provides insights into the relative slopes of the (4d−1)σ* and (CH3I2+)σ* potential surfaces. Data are also presented for the spectator decay of higher lying CH3I (I 4d−1)nl Rydberg resonances. Photoelectron angular distributions for the resonant Auger processes provide additional information that helps distinguish these processes from the direct ionization signal.
Hypochaos prevents tragedy of the commons in discrete-time eco-evolutionary game dynamics
Authors: Sohel Mondal Samrat , Ray Avishuman , Chakraborty Sagar
Published: February 2024

While quite a few recent papers have explored game-resource feedback using the framework of evolutionary game theory, almost all the studies are confined to using time-continuous dynamical equations. Moreover, in such literature, the effect of ubiquitous chaos in the resulting eco-evolutionary dynamics is rather missing. Here, we present a deterministic eco-evolutionary discrete-time dynamics in generation-wise non-overlapping population of two types of harvesters—one harvesting at a faster rate than the other—consuming a self-renewing resource capable of showing chaotic dynamics. In the light of our finding that sometimes chaos is confined exclusively to either the dynamics of the resource or that of the consumer fractions, an interesting scenario is realized: The resource state can keep oscillating chaotically, and hence, it does not vanish to result in the tragedy of the commons—extinction of the resource due to selfish indiscriminate exploitation—and yet the consumer population, whose dynamics depends directly on the state of the resource, may end up being composed exclusively of defectors, i.e., high harvesters. This appears non-intuitive because it is well known that prevention of tragedy of the commons usually requires substantial cooperation to be present.
Conducting polymer modified flexible and highly stable hydrovoltaic devices
Authors: Liu Libo , Qiu Jing , Song Hongrui , Li Mingyu , Liu Huanbin , Sun Hexuan
Published: February 2024

Various energy conversion devices have attracted much attention due to the rapid development of wearable microsensors and the increasing demand for continuous power supply. Among them, improving the performance of evaporation-based hydrovoltaic devices remains a meaningful endeavor. Here, we developed a conductive polymer modified flexible hydrovoltaic power generation device. By arranging the conducting polymer between the flexible substrate and the nanopore channel, the device can voltage output of 1 V and deliver more than 12 μA of current. Due to the durable attachment of the nanomaterials to the substrate, the device maintained over 60% of its electrical output capacity even after being immersed in water for 2 weeks. Improved substrate conductivity leads to an increase in over three times the current output. Furthermore, this device's output is influenced by changes in humidity, making it a viable respiratory monitoring sensor. The integration of polymer conductive materials has led to improved electrical output performance of hydrovoltaic devices, expanding their potential for applications.
Heating-induced release of trapped bubbles from dead-end pore throats filled with nonvolatile liquid
Authors: Wang Jinqing , Feng Zhi , Zhang Yinning , Zhang Muan , Zhan Mingxiu , Kong Ming , Xu Peng , Liu Jiyang , Xu Xu
Published: February 2024

The release of trapped bubbles from dead-end pore throats filled with nonvolatile liquid has widespread applications in gas–liquid reactors, radiators, foam flooding, ceramic sintering, and droplet microcarriers. As conventional pressure-driven flow cannot induce the transport of bubbles in dead-end pores, this paper explores the possibility of using heating to control the release of bubbles from dead-end pore throats. Visualization experiments of the microfluidics within a dead-end pore throat structure are conducted to address the release process of bubbles during heating. An increase in temperature causes dissolved gas in the solution to be transferred to the bubble, which enhances the bubble pressure and enables the bubble to pass through the pore throat. We analyze the effects of the initial bubble radius and initial temperature on the critical temperature Tcr at which the bubble passes through the pore throat. A larger initial radius does not necessarily make it more difficult for the bubble to pass through the throat, but there is a critical radius above which any increase in radius produces a lower value of Tcr. A theoretical model considering diffusion mass transfer, capillary forces, and corner film flows is developed, and this model is found to be in good agreement with the experimental results. Finally, we obtain three dimensionless numbers that can be used to predict Tcr. Our work provides guidance for the effective regulation of diffusive growth and the heating-induced release of bubbles from dead-end pore throats.
Revisiting the wake-triggered secondary vortices over a circular-cylinder/flat-plate configuration
Authors: Wang Jiangsheng , He Guosheng , Wang Jinjun
Published: February 2024

The wake-vortex/boundary-layer interaction is significant for both fundamental and practical aspects of fluid mechanics. The wake vortex triggered the well-known single-secondary vortex over a canonical circular-cylinder/flat-plate configuration. However, recent investigations reported wake-triggered double-secondary vortices over a multi-element airfoil or a simplified circular-cylinder/airfoil configuration. Motivated by this contrast, this paper revisits this topic with a circular-cylinder/flat-plate configuration and finally observes the double-secondary vortices in the boundary layer. The disturbances related to the shedding frequency of the wake vortex and its second harmonic are found to penetrate the boundary layer and be further amplified to form the double-secondary vortices.
Evaporation characteristics of cis-1,1,1,4,4,4-hexafluoro-2-butene (R1336mzz(Z)) droplet in high pressure and temperature environments
Authors: Yin Jing , Wang Qi-Di , Zhang Long-Fei , Norvihoho Leslie K. , Liu Bing , Zhou Zhi-Fu
Published: February 2024

Cis-1,1,1,4,4,4-hexafluoro-2-butene (R1336mzz(Z)) has emerged as an exceptionally promising low-global-warming-potential (GWP) refrigerant, ideal for spray cooling systems in the thermal management of electronic components. Research on the evaporation characteristics of an individual isolated cryogen droplet excludes uncertainties caused by droplet collisions and fusion, thereby laying the foundation for spray cooling. In this paper, a theoretical model for single R1336mzz (Z) droplet evaporation considering the effect of natural convection in a high pressure and temperature environment is proposed. The newly proposed model is validated by comparing the predicted results of the R1336mzz(Z) droplet evaporation with experimental data. Then, the effects of environmental temperature (323–523 K) and pressure (1–20 bar) on the R1336mzz(Z) droplet evaporation are investigated. The results reveal that the effect of increasing the ambient pressure on the droplet lifetime of R1336mzz(Z) undergoes a transition from deceleration to acceleration. Elevated temperature can promote droplet evaporation; however, the promoting effect of increasing the ambient temperature on droplet evaporation will be weakened in high-pressure cases. Increasing the ambient pressure and temperature both can enhance the heat transfer from the environment to the droplet through natural convection, while increasing the pressure greatly inhibits the molecular diffusion during droplet evaporation. Thus, the total evaporation rate depends on the competing effects of these two factors. In addition, the trend of the droplet temperature variation could differ based on droplet initial temperatures, ambient temperatures, and pressures. An increase in the ambient temperature or pressure corresponds to an increase in the droplet equilibrium temperature (Tequ). However, Tequ is almost independent of the droplet initial size and temperature.
Demonstration of MOCVD based in situ etching of β-Ga2O3 using TEGa
Authors: Katta Abishek , Alema Fikadu , Brand William , Gilankar Advait , Osinsky Andrei , Kalarickal Nidhin Kurian
Published: February 2024

In this work, we demonstrate an in situ etch technique for β-Ga2O3 inside a metalorganic chemical vapor deposition (MOCVD) reactor using triethylgallium (TEGa) as the etching agent. At sufficiently high substrate temperatures (Tsub), TEGa is introduced into the MOCVD reactor which undergoes pyrolysis, resulting in the deposition of Ga on the β-Ga2O3 surface. These Ga adatoms react with Ga2O3 to form gallium suboxide (Ga2O), which desorbs from the β-Ga2O3 surface resulting in the etching of the epilayer. MOCVD chamber parameters such as TEGa molar flow rate, substrate temperature, and chamber pressure were shown to be key in controlling the etch rate and surface morphology. A wide range of etch rates from ∼0.3 to 8.5 μm/h is demonstrated by varying the etch parameters. In addition, smooth surface morphology on (010) and (001) β-Ga2O3 substrates is also demonstrated. This new etch technique could enable damage free fabrication of 3D structures like fins and trenches, which are key components in many β-Ga2O3 device structures.
Numerical study on laser-induced cavitation bubble dynamics inside a millimetric droplet
Authors: Phan Thanh-Hoang , Nguyen Van-Tu , Duy Trong-Nguyen , Park Warn-Gyu
Published: February 2024

In this study, complicated nonlinear interactions of a single laser-induced cavitation bubble inside a millimetric water droplet were numerically investigated using a fully compressible three-phase homogeneous model. A general condensation phase-change model and high-resolution interface-capturing schemes were adopted to accurately predict the bubble collapsing and rebound stages as well as strongly deformable droplet interface evolutions. The numerical model was validated using experimental data in terms of the equivalent bubble radius until the second collapse stage, and good quantitative agreement was achieved. The variation in the droplet surface velocity was detected and could better reveal the mechanism underlying the complicated bubbles and droplet interactions, particularly in droplet surface splash dynamics. Subsequently, the complex bubble–droplet interaction phenomena were studied by investigating the ratio of the maximum bubble radius to the initial droplet radius. The numerical results show that the bubble collapsing time decreases monotonically with an increase in the bubble–droplet radius ratio. The droplet surface instabilities became more dominant as the radius ratio increased. In addition, four distinct patterns of droplet motion, namely, stable, multi-spike, ventilating jet, and splashing phenomena, were captured. Finally, the specific mechanisms leading to droplet surface jetting were identified.
Boosting exciton dissociation and charge transfer in CsPbBr
3
QDs via ferrocene derivative ligation for CO
2
photoreduction
Authors: Du Chenyu , Sheng Jianping , Zhong Fengyi , He Ye , Liu Huiyu , Sun Yanjuan , Dong Fan
Published: February 2024

Photo-catalytic CO
2
reduction with perovskite quantum dots (QDs) shows potential for solar energy storage, but it encounters challenges due to the intricate multi-electron photoreduction processes and thermodynamic and kinetic obstacles associated with them. This study aimed to improve photo-catalytic performance by addressing surface barriers and utilizing multiple-exciton generation in perovskite QDs. A facile surface engineering method was employed, involving the grafting of ferrocene carboxylic acid (FCA) onto CsPbBr
3
(CPB) QDs, to overcome limitations arising from restricted multiple-exciton dissociation and inefficient charge transfer dynamics. Kelvin Probe Force Microscopy and XPS spectral confirmed successfully creating an FCA-modulated microelectric field through the Cs active site, thus facilitating electron transfer, disrupting surface barrier energy, and promoting multi-exciton dissociations. Transient absorption spectroscopy showed enhanced charge transfer and reduced energy barriers, resulting in an impressive CO
2
-to-CO conversion rate of 132.8 μmol g
−1
h
−1
with 96.5% selectivity. The CPB-FCA catalyst exhibited four-cycle reusability and 72 h of long-term stability, marking a significant nine-fold improvement compared to pristine CPB (14.4 μmol g
−1
h
−1
). These results provide insights into the influential role of FCA in regulating intramolecular charge transfer, enhancing multi-exciton dissociation, and improving CO
2
photoreduction on CPB QDs. Furthermore, these findings offer valuable knowledge for controlling quantum-confined exciton dissociation to enhance CO
2
photocatalysis.
Self-powered piezoelectric sensor based on BaTiO3/MWCNTs/PVDF electrospun nanofibers for wireless alarm system
Authors: Liu Lei , Li Xueying , Gang Yongfeng , Cui Xin , Fan Bo , Dan Yuanyuan , Fang Jiwen
Published: February 2024

The piezoelectric constant of polyvinylidene fluoride (PVDF) is inferior to that of piezoelectric ceramics, which will impede the efficient application in smart systems. In this work, we modulated the content of BaTiO3/multi-wall carbon nanotubes (MWCNTs) in the BaTiO3/MWCNTs/PVDF electrospun nanofibers to facilitate the β phase formation in the PVDF to enhance the piezoelectric properties of BaTiO3/MWCNTs/PVDF films. The BaTiO3 combined with MWCNTs through chemical bands can enhance the electrostatic interaction at the vicinity of BaTiO3-PVDF interface to induce augmentation of the local conformational disorder and result in the enhanced nucleation and stabilization of β phase in the BaTiO3/MWCNTs/PVDF films. When the ratio between BaTiO3 and MWCNTs is about 3:1, the PVDF-BM-3 can deliver the output voltage of 39.5 V under 250 kPa with a frequency of 10 Hz. The PVDF-BM-3 electrospun nanofibers as triggers used in the wireless alarm system can achieve comparable sensitivity under different external stresses. This work paves a new promising pathway for self-powered piezoelectric sensors in the Internet of Things.
Room-temperature highly sensitive triethylamine detection by few-layer Nb2CT
x
MXene nanosheets
Authors: Wang Wenxing , Yao Yu , Xin Jiangang , Zhao Xueling , Xie Lili , Zhu Zhigang
Published: February 2024

MXene, a class of two-dimensional materials that are emerging as rising stars in the field of materials, are receiving much attention in sensing. Ti3C2T
x
MXene, the most maturely researched MXene, is widely used in energy, biomedical, laser, and microwave shielding applications and has also been expanded to gas sensing and wearable electronics applications. Compared with Ti3C2T
x
, Nb2CT
x
MXene is more difficult to etch and has higher resistances at room temperature; so, few studies have been reported on their use in the sensing field. Based on the preparation of few-layer Nb2CT
x
MXene by intercalation, this study thoroughly examined their gas-sensing properties. The successfully prepared few-layer Nb2CT
x
showed good selectivity and high sensitivity to triethylamine at room temperature, with response values up to 47.2% for 50 ppm triethylamine and short response/recovery time (22/20 s). This study opens an important path for the design of novel Nb-based MXene sensors for triethylamine gas detection.
Understanding the effects of annealing induced structural transformations on the UVC absorbance and other optical properties of RF sputter deposited Ga2O3 thin films
Authors: C S Keerthana , S Nair Anjana , K Sreepriya , James Jiya , Kumar Santhosh , Unnikrishnan N V , A C Saritha
Published: February 2024

Gallium oxide (Ga2O3) is a transparent material with high absorption in the UVC region of the electromagnetic spectrum and hence is a very important candidate in the field of short wavelength optical device fabrication. A proper understanding of the different optical parameters is necessary for developing more efficient coatings and devices. In this work, changes in the optical behavior of Ga2O3 thin films due to post-deposition annealing (at temperatures 300 °C–900 °C) are discussed in detail. Structural, surface morphological and compositional modifications of the films are identified using the x-ray diffractometer, scanning electron microscopy and x-ray photoelectron spectrometer techniques, respectively. At 900 °C, a highly stable monoclinic β phase of Ga2O3 is obtained. The optical transmittance spectra acquired using UV–Vis spectroscopy indicate an improved UVC absorbance of the β-Ga2O3 films with an excellent visible transmittance (>80%). The structural transformation from amorphous to crystalline β-Ga2O3 phase and the associated reduction in defect density is found to modify other optical attributes, like the bandgap energy, Urbach energy, dispersion parameters, etc.
Manufacturing of soft capacitive strain sensor based on dielectric elastomer material for an elastic element of a jaw coupling
Authors: Prokopchuk Artem , Ewert Arthur , Menning Johannes D M , Richter Andreas , Schlecht Berthold , Wallmersperger Thomas , Henke E-F Markus
Published: February 2024

In this work, we present a procedure for manufacturing a soft capacitive strain sensor in the form of a multi-layer electrical capacitor for further integration into the elastic gear rim of a jaw coupling. The dielectric elastomer sensor (DES) is based on an elastomeric substrate with alternating layers of conductive carbon black based ink as electrode layers and elastomeric film as a dielectric and electrical insulation. A variety of thin multi-layer sensors were produced to evaluate the manufacturing process. Additionally, using an LCR meter and a tensile test machine, the equivalent electrical capacitance (C) at the two sensor contacts and the applied force are measured, respectively. It is shown that C varies depending on the amount of sample strain caused by the applied force. By testing two versions of DES, a maximum change in capacitance of ΔC = 1.55 pF was achieved. The obtained characteristics show that the presented manufacturing process for the DES can be used as a soft strain sensor to measure the strain caused by the force applied to the elastic element between the jaw couplings.
Qualitative switches in single-neuron spike dynamics on neuromorphic hardware: implementation, impact on network synchronization and relevance for plasticity
Authors: Weerdmeester Liz , Niemeyer Nelson , Pfeiffer Paul , Billaudelle Sebastian , Schemmel Johannes , Schleimer Jan-Hendrik , Schreiber Susanne
Published: February 2024

Most efforts on spike-based learning on neuromorphic hardware focus on synaptic plasticity and do not yet exploit the potential of altering the spike-generating dynamics themselves. Biological neurons show distinct mechanisms of spike generation, which affect single-neuron and network computations. Such a variety of spiking mechanisms can only be mimicked on chips with more advanced, nonlinear single-neuron dynamics than the commonly implemented leaky integrate-and-fire neurons. Here, we demonstrate that neurons on the BrainScaleS-2 chip configured for exponential leaky integrate-and-fire dynamics can be tuned to undergo a qualitative switch in spike generation via a modulation of the reset voltage. This switch is accompanied by altered synchronization properties of neurons in a network and thereby captures a main characteristic of the unfolding of the saddle-node loop bifurcation—a qualitative transition that was recently demonstrated in biological neurons. Using this switch, cell-intrinsic properties alone provide a means to control whether small networks of all-to-all coupled neurons on the chip exhibit synchronized firing or splayed-out spiking patterns. We use an example from a central pattern generating circuit in the fruitfly to show that such dynamics can be induced and controlled on the chip. Our study thereby demonstrates the potential of neuromorphic chips with relatively complex and tunable single-neuron dynamics such as the BrainScaleS-2 chip, to generate computationally distinct single unit dynamics. We conclude with a discussion of the utility of versatile spike-generating mechanisms on neuromorphic chips.
How machines can make mathematics more congressive
Authors: Cheng Eugenia
Published: February 2024

I argue that since technology is already changing the way we do mathematics, we can use this technology to allow mathematics to be more congressive without human mathematicians becoming redundant in the face of technological advances. In thinking about what it means to “do mathematics,” I examine the following aspects of technology in mathematics: teaching and learning, asking questions, collaboration, dissemination, and the act of doing research. This is not intended to be a rigorous analysis but an informed reflection based on my experience as a mathematician.
Flexiplex: a versatile demultiplexer and search tool for omics data
Authors: Cheng Oliver , Ling Min Hao , Wang Changqing , Wu Shuyi , Ritchie Matthew E , Göke Jonathan , Amin Noorul , Davidson Nadia M
Published: February 2024

Motivation

The process of analyzing high throughput sequencing data often requires the identification and extraction of specific target sequences. This could include tasks, such as identifying cellular barcodes and UMIs in single-cell data, and specific genetic variants for genotyping. However, existing tools, which perform these functions are often task-specific, such as only demultiplexing barcodes for a dedicated type of experiment, or are not tolerant to noise in the sequencing data.

Results

To overcome these limitations, we developed Flexiplex, a versatile and fast sequence searching and demultiplexing tool for omics data, which is based on the Levenshtein distance and thus allows imperfect matches. We demonstrate Flexiplex’s application on three use cases, identifying cell-line-specific sequences in Illumina short-read single-cell data, and discovering and demultiplexing cellular barcodes from noisy long-read single-cell RNA-seq data. We show that Flexiplex achieves an excellent balance of accuracy and computational efficiency compared to leading task-specific tools.

Availability and implementation

Flexiplex is available at https://davidsongroup.github.io/flexiplex/.
Water storage capacity of closed-shell silicon oxyhydroxide cluster cations in the gas phase
Authors: Nagata Toshiaki , Miyajima Ken , Mafuné Fumitaka
Published: February 2024

Stable compositions and H2O desorption processes of SinO2n+iH2i+1⁠+ (nominally, (SiO2)n(H2O)iH+; n = 3 to 10) clusters have been studied by gas-phase thermal desorption spectrometry coupled with density functional theory (DFT) calculations. Five or six H2O molecules were found to be stored (i = 5, 6) mainly in the clusters at room temperature. The clusters sequentially released H2O molecules upon heating to form the species with i = 2 (n = 3–5, 8) and 3 (n = 6, 7, 9, 10) as the most prominent compositions at 1,000 K. The desorption energies of H2O molecules from the clusters were evaluated from the temperature dependence data for n = 3 to 5. The experimental and theoretical results suggest that (SiO2)n(H2O)iH+ clusters with higher i (e.g. i ≥ 4 for n = 3) involve H2O molecules bound with hydrogen bonds and can easily release the H2O molecules (ΔE < ∼0.5 eV); species with lower i (e.g. i = 2 and 3 for n = 3) form H2O molecules from two hydroxide groups, whose desorption requires higher energies (ca. 1 to 2 eV); and H2O release is hampered if the product species does not maintain the structure with tetrahedrally coordinated Si atoms.
Viral reactivation following COVID-19 vaccination: a review of the current literature
Authors: Martora Fabrizio , Megna Matteo , Battista Teresa , Scalvenzi Massimiliano , Villani Alessia , Cacciapuoti Sara , Potestio Luca
Published: February 2024

Currently, four vaccines for COVID-19 have been licensed by the European Medicines Agency: two viral vector-based vaccines and two mRNA-based vaccines. Since their approval, several cutaneous reactions related to vaccination have been reported in the literature. Among these, viral reactivations are one of the most frequent. The aim of this article was to investigate the current literature regarding viral reactivations following COVID-19 vaccination, focusing attention on pityriasis rosea (PR), herpes zoster and herpes simplex. A comprehensive literature search using various databases was performed and we included metanalyses, reviews, letters to the editor, real-life studies, case series and reports. A total of 48 articles involving 2067 patients were selected. Of these, 32, 6 and 17 articles reported varicella zoster virus (VZV) reactivation (1758 patients), herpes simplex virus (HSV) (238 patients) onset and PR (71 patients), respectively (some articles discussed more than one of these three reactivations). Possible pathogenetic mechanisms underlying viral reactivation are still not understood. Also, the possible correlations between vaccination and viral reactivation should be clarified. Certainly, vaccination should not be discouraged.
Moment-dependent rupture properties of deep-focus earthquakes in the Izu-Bonin subduction zone
Authors: Kehoe H L , Kiser E D
Published: February 2024

The physical mechanisms controlling deep-focus earthquakes, or those observed at depths greater than 300 km, remain enigmatic. The leading processes by which deep-focus earthquakes are thought to occur include transformational faulting, thermal runaway and dehydration embrittlement, but distinguishing observations in support of one or more prevailing mechanisms are needed. In this study, we use a modified back-projection method, data recorded by the Hi-net array in Japan and a 3-D velocity model to produce source images of 19 deep-focus earthquakes within the Izu-Bonin subduction zone. We find that the rupture properties and fault plane orientations of imaged events separate according to reported moment magnitude, indicating the distinct operation of two moment-dependent causal mechanisms of deep-focus earthquakes in this region. We discuss these results in the context of previous observational, laboratory and numerical studies and emphasize the importance of continued research to validate the dual-mechanism hypothesis both in and outside Izu-Bonin. Such work may not only improve our understanding of the nucleation and propagation of deep-focus earthquakes, but also help clarify slab structure and subduction zone dynamics.
Could giant viruses be considered as a biotechnological tool for preventing and controlling Acanthamoeba infections?
Authors: Crispim Ana Paula Correia , Serafim Mateus Sá Magalhães , Costa Adriana Oliveira , Abrahão Jônatas Santos
Published: February 2024

Aim

The aim of the study was to evaluate the efficiency of mimivirus as a potential therapeutic and prophylactic tool against Acanthamoeba castellanii, the etiological agent of Acanthamoeba keratitis, a progressive corneal infection, that is commonly associated with the use of contact lenses and can lead to blindness if not properly treated.

Methods and results

Mimivirus particles were tested in different multiplicity of infection, along with commercial multipurpose contact lenses’ solutions, aiming to assess their ability to prevent encystment and excystment of A. castellanii. Solutions were evaluated for their amoebicidal potential and cytotoxicity in MDCK cells, as well as their effectiveness in preventing A. castellanii damage in Madin-Darby canine kidney (MDCK) cells. Results indicated that mimivirus was able to inhibit the formation of A. castellanii cysts, even in the presence of Neff encystment solution. Mimivirus also showed greater effectiveness in controlling A. castellanii excystment compared to commercial solutions. Additionally, mimivirus solution was more effective in preventing damage caused by A. castellanii, presented greater amoebicidal activity, and were less cytotoxic to MDCK cells than commercial MPS.

Conclusions

Mimivirus demonstrates a greater ability to inhibit A. castellanii encystment and excystment compared to commercial multipurpose contact lens solutions. Additionally, mimivirus is less toxic to MDCK cells than those commercial solutions. New studies utilizing in vivo models will be crucial for confirming safety and efficacy parameters.
The identification of minor impact collisions in a long video for detecting property damages caused by fleeing vehicles using three-dimensional convolutional neural network
Authors: Hwang Inwoo , Lee Yong-Gu
Published: February 2024

A parked vehicle damaged by a hit-and-run can only be repaired at the expense of the owner, unless the fleeing vehicle is identified and the driver apprehended. Identifying the fleeing vehicle involves using a video investigation method that searches for perpetrators through CCTV footage of the crime scene. When the length of the recorded video is long, the investigation may require an extended amount of time from the investigator, resulting in an added burden on their daily work. Some commercial companies are using object recognition and tracking technology to detect hit-and-run incidents; however, detecting small movements of a vehicle during a minor collision still remains a challenge. Therefore, there is a need for a system that can detect small movement in a vehicle in a lengthy video. Automatic recognition and tracking require a sufficient amount of training dataset. However, such a dataset for hit-and-run incidents is not publicly available. One of the reasons behind this scarcity is that it may violate personal information protection acts. On the other hand, instead of using real accident videos, we could use actors to simulate such accident scenes. Although this may be feasible, creating such a dataset would require substantial costs. In this paper, we describe a new dataset for hit-and-run incidents. We collected 833 hit-and-run videos by recreating a parking lot using miniaturized cars. This dataset has been made publicly available through Kaggle. We used three-dimensional convolution neural network, which is frequently used in the field of action recognition, to detect small movements of vehicles during hit-and-run incidents. In addition, the proportion of the area that surrounds the target vehicle to the min-max box of the vehicle itself and the length of the input frame are varied to compare the accuracy. As a result, we were able to achieve better accuracy by using the lowest proportion and the shortest input frame.
Stigma Resistance through Body-in-Practice: Embodying Pride through Creative Mastery
Authors: Venkatraman Rohan , Ozanne Julie L , Coslor Erica
Published: February 2024

Stigma, as a process of shame, fosters social exclusion and diminishes bodily competences. Thus, stigmatized consumers often turn to the marketplace for respite. Based on an ethnographic study of drag artists, this study proposes a new understanding of the body that emerges from the mastery of creative consumption practices to combat shame. We theorize a novel “body-in-practice” framework to examine how consumers transform from an imagined persona to an accomplished body to embody pride. Six novel stigma resistance strategies emerged—experimenting, guarding, risk-taking, spatial reconfiguring, self-affirming, and integrating. Body-in-practice thus explains how shame weakens, pride strengthens, emotions stabilize, and self-confidence grows. This research contributes by explaining the hard work of identity repair, exploring stigma resistance across safe and hostile social spaces, and highlighting the emancipatory potential of embodied mastery.
Conservation genomics of wolves: The global impact of RK Wayne’s research
Authors: Musiani Marco , Randi Ettore
Published: February 2024

RK Wayne has arguably been the most influential geneticist of canids, famously promoting the conservation of wolves in his homeland, the United States. His influence has been felt in other countries and regions outside the contiguous United States, where he inspired others, also including former graduate students and research fellows of his, to use modern molecular techniques to examine the evolutionary biology of canids to inform the conservation and management of wolves. In this review, we focus on the implications of Wayne’s work on wolves outside the United States. He envisioned a clear future for wolf conservation research, involving the study of wolves’ ecological and genetic diversity, and the description of ecotypes requiring conservation. He also documented widespread hybridization among canids and introgression of DNA from domestic dogs to wolves, a process that started dozens of thousands of years ago. His work therefore calls for innovative studies, such as examining the potential fitness benefits of introgression. Inspired by his results, for example, on the purging of deleterious alleles in small populations, wolf researchers should use novel molecular tools to challenge other conservation genetics paradigms. Overall, RK Wayne’s work constitutes a call for answers, which as scientists or citizens concerned with conservation matters, we are obliged to address, as we contribute to monitoring and maintaining biodiversity during our period of dramatic transformations of the biosphere.
Effect of cosmic rays and ionizing radiation on observational ultraviolet plasma diagnostics in the circumgalactic medium
Authors: Holguin F , Farber R , Werk J
Published: February 2024

The relevance of some galactic feedback mechanisms, in particular cosmic-ray (CR) feedback and the hydrogen ionizing radiation field, has been challenging to definitively describe in a galactic context, especially far outside the galaxy in the circumgalactic medium (CGM). Theoretical and observational uncertainties prevent conclusive interpretations of multiphase CGM properties derived from ultraviolet (UV) diagnostics. We conduct three-dimensional magnetohydrodynamic simulations of a section of a galactic disc with star formation and feedback, including radiative heating from stars, a UV background, and CR feedback. We utilize the temperature phases present in our simulations to generate Cloudy models to derive spatially and temporally varying synthetic UV diagnostics. We find that radiative effects without additional heating mechanisms are not able to produce synthetic diagnostics in the observed ranges. For low CR diffusivity $\kappa _{\rm {cr}}=10^{28} \rm {cm}^2 \rm {s}^{-1}$, CR streaming heating in the outflow helps our synthetic line ratios roughly match observed ranges by producing transitional temperature gas (T ∼ 105–106 K). High CR diffusivity $\kappa _{\rm {cr}}=10^{29} \rm {cm}^2 \rm {s}^{-1}$, with or without CR streaming heating, produced transitional temperature gas. The key parameter controlling the production of this gas phase remains unclear, as the different star formation history and outflow evolution itself influences these diagnostics. Our work demonstrates the use of UV plasma diagnostics to differentiate between galactic/circumgalactic feedback models.
Measuring neutrino mass and asymmetry with matter pairwise velocities
Authors: Zhang Wangzheng , Chu Ming-chung , Hu Rui , Liao Shihong , Yeung Shek
Published: February 2024

Neutrinos are believed to be the most abundant fermions in the Universe, but their masses are unknown, except for being non-zero but much smaller than other fermions. Cosmological relic neutrinos could also have non-zero chemical potentials (or asymmetries). Using neutrino-involved N-body simulations, we investigate the neutrino effects on the matter pairwise velocity, which itself is an interesting probe of cosmology. We find that for light-halo ([1011, 1013] M⊙) mean pairwise velocity, in the transition range ([4, 15] Mpc), the effects of neutrino masses overwhelm the effects of neutrino asymmetries, while in the two-halo-group range ([25, 50] Mpc), for both light and heavy haloes ([1013, 1015] M⊙), the effects of neutrino asymmetries dominate, making it possible to disentangle the two effects. We provide fitting formulae to quantify the effects of neutrino mass and asymmetry on halo–halo pairwise velocities.
Rayleigh and Raman scattering cross-sections and phase matrices of the ground-state hydrogen atom, and their astrophysical implications
Authors: Kokubo Mitsuru
Published: February 2024

We present explicit expressions for Rayleigh and Raman scattering cross-sections and phase matrices of the ground 1s state hydrogen atom based on the Kramers–Heisenberg–Waller dispersion formula. The Rayleigh scattering leaves the hydrogen atom in the ground-state while the Raman scattering leaves the hydrogen atom in either ns (n ≥ 2; s-branch) or nd (n ≥ 3; d-branch) excited state, and the Raman scattering converts incident ultraviolet (UV) photons around the Lyman resonance lines into optical-infrared (IR) photons. We show that this Raman wavelength conversion of incident flat UV continuum in dense hydrogen gas with a column density of NH > 1021 cm−2 can produce broad emission features centred at Balmer, Paschen, and higher level lines, which would mimic Doppler-broadened hydrogen lines with the velocity width of ≳1000 km s−1 that could be misinterpreted as signatures of active galactic nuclei, supernovae, or fast stellar winds. We show that the phase matrix of the Rayleigh and Raman s-branch scatterings is identical to that of the Thomson scattering while the Raman d-branch scattering is more isotropic, thus the Paschen and higher level Raman features are depolarized compared to the Balmer features due to the flux contribution from the Raman d-branch. We argue that observations of the line widths, line flux ratios, and linear polarization of multiple optical/IR hydrogen lines are crucial to discriminate between the Raman-scattered broad emission features and Doppler-broadened emission lines.
Insight from JWST/Near Infrared Camera into galaxy overdensities around bright Lyman-alpha emitters during reionization: implications for ionized bubbles at z ∼ 9
Authors: Whitler Lily , Stark Daniel P , Endsley Ryan , Chen Zuyi , Mason Charlotte , Topping Michael W , Charlot Stéphane
Published: February 2024

Several studies have detected Lyman-alpha (Ly α) from bright ($M_{\small UV}\lesssim -21.5$) galaxies during the early stages of reionization despite the significantly neutral intergalactic medium. To explain these detections, it has been suggested that z > 7 Ly α emitters (LAEs) inhabit physical Mpc (pMpc)-scale ionized regions powered by overdensities of faint galaxies; however, systematic searches for these overdensities near LAEs have been challenging. Here, we use Cosmic Evolution Early Release Science JWST/Near Infrared Camera imaging to search for large-scale galaxy overdensities near two very ultraviolet (UV)-bright, z = 8.7 LAEs in the Extended Groth Strip (EGS) field. We colour select 27 z = 8.4–9.1 candidates, including the one LAE in the footprint (EGSY8p7). From spectral energy distribution models, we infer moderately faint UV luminosities ($-21.2\lesssim {M_{\small UV}}\lesssim -19.1$) and stellar masses of M* ≈ 107.5–8.8 M⊙. All are efficient ionizing agents ($\xi _{\text{ion}}^{*}\approx 10^{25.5-26.0}$ Hz erg−1) and are generally morphologically simple with only one compact (re ≲ 140 to ∼650 pc) star-forming component. 13 candidates lie within 5 arcmin of EGSY8p7, leading to a factor-of-four galaxy overdensity at ≲5 arcmin (∼1.4 projected pMpc at z ∼ 8.7) separations from EGSY8p7. Separations of 10–15 arcmin (∼2.7–4.1 projected pMpc) are consistent with an average field. The spatial distribution of our sample may qualitatively suggest an R ≥ 2 pMpc ionized bubble encompassing both LAEs in EGS, which is theoretically unexpected but may be possible for a galaxy population four times more numerous than the average to create with moderate escape fractions (fesc ≳ 0.15) over long times (≳ 200 Myr). Upcoming spectroscopic follow-up will characterize the size of any ionized bubble that may exist and the properties of the galaxies powering such a bubble.
On the origin of outward migration of Population III stars
Authors: Park Jongwon , Ricotti Massimo , Sugimura Kazuyuki
Published: February 2024

Outward migration of massive binary stars or black holes in their circumbinary disc is often observed in simulations and it is key to the formation of wide black hole binaries. Using numerical simulations of Population III (Pop III) star formation, we study the angular momentum of Pop III binaries and the torques between stars and gas discs to understand the origin of outward migration and high ellipticity. The outward migration of protostars is produced by gravitational torques exerted on them by their circumstellar minidiscs. The minidiscs, on the other hand, migrate outward mainly by gaining angular momentum by accreting gas from the circumbinary disc. The angular momentum transfer is most efficient for rapidly accreting equal-mass binaries, and weaker when the secondary mass is small or the massive companion evaporates the gas disc via radiative feedback. We conclude that outward migration and the formation of wide equal-mass massive binaries is common in metal-free/metal-poor star formation, mainly driven by their large accretion rates. We expect that the lower gas temperature and accretion rates in metal-enriched circumstellar discs would lead more often to inward migration and closer binary separations. We also observe inward migration for smaller mass Pop III protostars/fragments, leading to the rapid merging of sink particles and likely the formation of close binary black holes that, however, reach separations below the resolution of our simulations. We discuss the implications that Pop III separations and ellipticity may have on the interpretation that gravitational wave signals from merging intermediate-mass black holes come from Pop III remnants.
Search for Stellar Companions of Exoplanet Host Stars with AstraLux/CAHA 2.2 m
Authors: Schlagenhauf Saskia , Mugrauer Markus , Ginski Christian , Buder Sven , Fernández Matilde , Bischoff Richard
Published: February 2024

Stellar multiplicity is a key aspect of exoplanet diversity, as the presence of more than one star in a planetary system can have both devastating and positive effects on its formation and evolution. In this paper, we present the results of a Lucky Imaging survey of 212 exoplanet host stars performed with AstraLux at the 2.2 m telescope of the Centro Astronómico Hispano en Andalucía. The survey includes data from seven observing epochs between August 2015 and September 2020, and data for individual targets from four earlier observing epochs. The targets of this survey are nearby, bright, solar-like stars with high proper motions. In total, we detected 46 co-moving companions of 43 exoplanet host stars. Accordingly, this survey shows that the minimum multiplicity rate of exoplanet host stars is $20 \pm 3~{\rm per\ cent}$. In total, 33 binary and 10 hierarchical triple star systems with exoplanets have been identified. All companions were found to have a common proper motion with the observed exoplanet host stars, and with our astrometry we even find evidence of orbital motion for 28 companions. For all targets, we determine the detection limit and explore the detection space for possible additional companions of these stars. Based on the reached detection limit, additional co-moving companions beyond the detected ones can be excluded around all observed exoplanet host stars. The increasing number of exoplanets discovered in multiple stellar systems suggests that the formation of planets in such systems is by no means rare, but common. Therefore, our study highlights the need to consider stellar multiplicity in future studies of exoplanet habitability.
The physical properties of Fermi-4LAC low-synchrotron-peaked BL Lac objects
Authors: Hu Hai-Bin , Wang Hai-Qin , Xue Rui , Peng Fang-Kun , Wang Ze-Rui
Published: February 2024

Previous studies on the fitting of spectral energy distributions (SEDs) often apply the external-Compton process to interpret the high-energy peak of low-synchrotron-peaked (LSP) BL Lac objects (LBLs), despite the lack of strong broad emission lines observed for LBLs. In this work, we collect quasi-simultaneous multiwavelength data of 15 LBLs from the Fermi fourth LAT AGN catalogue (4LAC). We propose an analytical method to assess the necessity of external photon fields in the framework of one-zone scenario. Following derived analytical results, we fit the SEDs of these LBLs with the conventional one-zone leptonic model and study their jet physical properties. Our main results can be summarized as follows. (1) We find that most LBLs cannot be fitted by the one-zone synchrotron-self-Compton (SSC) model. This indicates that external photons play a crucial role in the high-energy emission of LBLs, therefore we suggest that LBLs are masquerading BL Lacs. (2) We suggest that the γ-ray emitting regions of LBLs are located outside the broad-line region and within the dusty torus. (3) By extending the analytical method to all types of LSPs in Fermi-4LAC (using historical data), we find that the high-energy peaks of some flat spectrum radio quasars and blazar candidates of unknown types can be attributed to the SSC emission, implying that the importance of external photons could be minor. We suggest that the variability time-scale may help distinguish the origin of the high-energy peak.
Constructing the three-dimensional extinction density maps using V-net
Authors: Chen Bing-Qiu , Qin Fei , Li Guang-Xing
Published: February 2024

One of the major challenges we face is how to quickly and accurately create the three-dimensional (3D) density distributions of interstellar dust in the Milky Way using extinction and distance measurements of large samples of stars. In this study, we introduce a novel machine-learning approach that utilizes a convolution neural network, specifically a V-net, to infer the 3D distribution of dust density. Experiments are performed within two regions located towards the Galactic anticentre. The neural network is trained and tested using 10 000 simulations of dust density and line-of-sight extinction maps. Evaluation of the test sample confirms the successful generation of dust density maps from extinction maps by our model. Additionally, the performance of the trained network is evaluated using data from the literature. Our results demonstrate that our model is capable of capturing detailed dust density variations and can recover dust density maps while reducing the ‘fingers of god’ effect. Moving forward, we plan to apply this model to real observational data to obtain the fine distribution of dust at large and small scales in the Milky Way.