bluuebunny/crossref_metadata_2025 huggingface dataset:
Universal Anderson localization in one-dimensional unitary maps
Authors: Vakulchyk Ihor , Flach Sergej
Published: August 2023

We study Anderson localization in discrete-time quantum map dynamics in one dimension with nearest-neighbor hopping strength θ and quasienergies located on the unit circle. We demonstrate that strong disorder in a local phase field yields a uniform spectrum gaplessly occupying the entire unit circle. The resulting eigenstates are exponentially localized. Remarkably this Anderson localization is universal as all eigenstates have one and the same localization length Lloc. We present an exact theory for the calculation of the localization length as a function of the hopping, 1/Lloc=|ln⁡(|sin⁡(θ)|)|, which is tunable between zero and infinity by variation of the hopping θ.
Analog of a Laplace–Runge–Lenz vector for particle orbits (time-like geodesics) in Schwarzschild spacetime
Authors: Anco Stephen C. , Fazio Jordan A.
Published: August 2023

In Schwarzschild spacetime, time-like geodesic equations, which define particle orbits, have a well-known formulation as a dynamical system in coordinates adapted to the time-like hypersurface containing the geodesic. For equatorial geodesics, the resulting dynamical system is shown to possess a conserved angular quantity and two conserved temporal quantities, whose properties and physical meaning are analogs of the conserved Laplace–Runge–Lenz vector, and its variant known as Hamilton’s vector, in Newtonian gravity. When a particle orbit is projected into the spatial equatorial plane, the angular quantity yields the coordinate angle at which the orbit has either a turning point (where the radial velocity is zero) or a centripetal point (where the radial acceleration is zero). This is the same property as the angle of the respective Laplace–Runge–Lenz and Hamilton vectors in the plane of motion in Newtonian gravity. The temporal quantities yield the coordinate time and the proper time at which those points are reached on the orbit. In general, for orbits that have a single turning point, the three quantities are globally constant, and for orbits that possess more than one turning point, the temporal quantities are just locally constant as they jump at every successive turning point, while the angular quantity similarly jumps only if an orbit is precessing. This is analogous to the properties of a generalized Laplace–Runge–Lenz vector and generalized Hamilton vector which are known to exist for precessing orbits in post-Newtonian gravity. The angular conserved quantity is used to define a direct analog of these vectors at spatial infinity.
An introduction to the unpublished book “Reflections on a Tube” by Mitchell J. Feigenbaum
Authors: Eckmann Jean-Pierre
Published: August 2023

This paper is an adaptation of the introduction to a book project by the late Mitchell J. Feigenbaum (1944–2019). While Feigenbaum is certainly mostly known for his theory of period doubling cascades, he had a lifelong interest in optics. His book project is an extremely original discussion of the apparently very simple study of anamorphs, that is, the reflections of images on a cylindrical mirror. He observed that there are two images to be seen in the tube and discovered that the brain preferentially chooses one of them. I edited and wrote an introduction to this planned book. As the book is still not published, I have now adapted my introduction as a standalone article so that some of Feigenbaum’s remarkable work will be accessible to a larger audience.
Mapping the frontier orbital energies of imidazolium-based cations using machine learning
Authors: Dhakal Pratik , Gassaway Wyatt , Shah Jindal K.
Published: August 2023

The knowledge of the frontier orbital, highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO), energies is vital for studying chemical and electrochemical stability of compounds, their corrosion inhibition potential, reactivity, etc. Density functional theory (DFT) calculations provide a direct route to estimate these energies either in the gas-phase or condensed phase. However, the application of DFT methods becomes computationally intensive when hundreds of thousands of compounds are to be screened. Such is the case when all the isomers for the 1-alkyl-3-alkylimidazolium cation [CnCmim]+ (n = 1–10, m = 1–10) are considered. Enumerating the isomer space of [CnCmim]+ yields close to 386 000 cation structures. Calculating frontier orbital energies for each would be computationally very expensive and time-consuming using DFT. In this article, we develop a machine learning model based on the extreme gradient boosting method using a small subset of the isomer space and predict the HOMO and LUMO energies. Using the model, the HOMO energies are predicted with a mean absolute error (MAE) of 0.4 eV and the LUMO energies are predicted with a MAE of 0.2 eV. Inferences are also drawn on the type of the descriptors deemed important for the HOMO and LUMO energy estimates. Application of the machine learning model results in a drastic reduction in computational time required for such calculations.
Shock recompression of the metal spall fracture region based on macroscopic simulations
Authors: Liu Jun , Gao Cong-Zhang , Zhao Yan-Hong , Sun Zhi-Yuan , Yin Jian-Wei , He An-Min , Wang Pei
Published: August 2023

We study shock recompression of the metal spall fracture region using macroscopic simulations in a wide range of initial parameters. Recompression states are mainly analyzed based on different simulation methods. First, we employ an empirical numerical treatment within the fracture post-processing model, resulting in a good agreement with experimental data of porous metals. To further validate its applicability, we carry out direct simulations that distinguish various initial fractured states, and we find that the influence of an initial fractured state on the recompression state is remarkable, especially the temperature. By comparing recompression states calculated by two different simulation methods, it reveals that empirical-treatment-based simulations actually describe fragment-state recompression. The present study shows that empirical-treatment-based simulations are physically capable of describing the shock recompression of fractured metals, which might be potentially used to investigate detonation-driven experiments with more complicated physical scenarios.
Bursting multistability induced by double-Hopf bifurcation
Authors: Xia Yibo , Yanchuk Serhiy , Cao Yichuan , Bi Qinsheng , Kurths Jürgen
Published: August 2023

We study the slow–fast dynamics of a system with a double-Hopf bifurcation and a slowly varying parameter. The model consists of coupled Bonhöffer–van der Pol oscillators excited by a periodic slow-varying AC source. We consider two cases where the slowly varying parameter passes by or crosses the double-Hopf bifurcation, respectively. Due to the system’s multistability, two bursting solutions are observed in each case: single-mode bursting and two-mode bursting. Further investigation reveals that the double-Hopf bifurcation causes a stable coexistence of these two bursting solutions. The mechanism of such coexistence is explained using the slowly changing phase portraits of the fast subsystem. We also show the robustness of the observed effect in the vicinity of the double-Hopf bifurcation.
Impact of coupling on neuronal extreme events: Mitigation and enhancement
Authors: Roy Anupama , Sinha Sudeshna
Published: August 2023

We focus on the emergence of extreme events in a collection of aperiodic neuronal maps, under local diffusive coupling, as well as global mean-field coupling. Our central finding is that local diffusive coupling enhances the probability of occurrence of both temporal and spatial extreme events, while in marked contrast, global mean-field coupling suppresses extreme events. So the nature of the coupling crucially determines whether the extreme events are enhanced or mitigated by coupling. Further, in globally coupled systems, there exist initial states in a window of coupling strength that exhibit spatial extreme events, but not temporal extreme events, suggesting that spatial extreme events do not imply temporal extreme events. We also explored the existence of discernible patterns in the return maps of successive inter-event intervals in order to gauge short-term risk-assessment. We find that single neuronal maps, as well as systems under strong diffusive coupling, display broad noisy patterns in these return maps, with clusters around characteristic intervals, allowing some short-term predictability in the extreme event sequence. In contrast, under weak diffusive coupling and global coupling, inter-event intervals lose all perceptible correlations, and the distribution extends to very large inter-event intervals. Lastly, we investigated a non-local diffusive coupling form. Interestingly, this coupling yielded a large window where temporal extreme events occurred, but the spatial profile was synchronized, namely, we found synchronized temporal extreme events. Such synchronized extreme spiking is reminiscent of the neuronal activity leading to epileptic seizures and is of potential relevance to extreme events in brain activity.
Double-quantum spectroscopy of dense atomic vapors: Interplay between Doppler and self-broadenings
Authors: Falvo Cyril , Li Hebin
Published: August 2023

In this article, we present a simulation study of the linear and nonlinear spectroscopy of dense atomic vapors. Motivated by recent experiments, we focus on double quantum spectroscopy, which directly probes dipole–dipole interactions. By explicitly including thermal velocity, we show that temperature has an important impact on the self-broadening mechanisms of the linear and nonlinear spectra. We also provide analytical expressions for the response functions in the short time limit using the two-body approximation, which shows that double quantum spectroscopy for atomic vapors directly probes the transition amplitude of the electronic excitation between two atoms. We also propose an expression for the double quantum spectrum that includes the effect of Doppler broadening, and we discuss the effect of density on the spectrum. We show that when Doppler broadening is negligible compared to self-broadening, the double quantum spectrum scales with the atomic density, while when Doppler broadening dominates, it scales as the square of the density.
Spin-0 fields and the NP-constants close to spatial infinity in Minkowski spacetime
Authors: Gasperín Edgar , Pinto Rafael
Published: August 2023

Newman–Penrose (NP) constants of massless spin-0 fields propagating in Minkowski spacetime are computed close to spatial and null infinity by means of Friedrich’s i0-cylinder. Assuming a certain regularity condition on the initial data ensuring that the field extends analytically to critical sets, it is shown that the NP constants at future I+ and past null infinity I− are independent of each other. In other words, the classical NP constants at I± stem from different parts of the initial data given on a Cauchy hypersurface. In contrast, it is shown that, using a slight generalization of the classical NP constants, the associated quantities (i0-cylinder NP constants) do not require the regularity condition being satisfied and give rise to conserved quantities at I± that are determined by the same piece of initial data, which, in turn, correspond to the terms controlling the regularity of the field. Additionally, it is shown how the conservation laws associated with the NP constants can be exploited to construct, in flat space, heuristic asymptotic-system expansions, which are sensitive to the logarithmic terms at the critical sets.
Turning an energy-based defect detector into a multi-molecule structural indicator for water
Authors: Loubet Nicolás A. , Verde Alejandro R. , Lockhart Jano A. , Appignanesi Gustavo A.
Published: August 2023

Recent studies have provided conclusive evidence for the existence of a liquid–liquid critical point in numerical models of water. Such a scenario implies the competition between two local molecular arrangements of different densities: a high-density liquid (HDL) and a low-density liquid (LDL). Within this context, the development of accurate structural indicators to properly characterize the two interconverting local structures is demanded. In a previous study, we introduced a reliable energy-based structural descriptor that properly discriminates water molecules into tetrahedrally arranged molecules (T molecules) and distorted molecules (D molecules). The latter constitute defects in terms of hydrogen bond (HB) coordination and have been shown to represent a minority component, even at high temperatures above the melting point. In addition, the D molecules tend to form high-quality HBs with three T molecules and to be surrounded by T and D molecules at further distances. Thus, it became evident that, while the LDL state might consist of a virtually pure T state, the HDL state would comprise mixed molecular arrangements including the D molecules. Such a need to abandon the single-molecule description requires the investigation of the degree of structural information to be incorporated in order to build an appropriate multi-molecule indicator. Hence, in this work, we shall study the effect of the local structural constraints on the water molecules in order to discriminate the different molecular arrangements into two disjoint classes. This will enable us to build a multi-molecule structural indicator for water whose performance will then be investigated within the water’s supercooled regime.
Experimental study on the pressure drop characteristics of a supercritical CO2/R134a mixture in a rectangular microchannel
Authors: Zhang Hongfei , Shi Lingfeng , Wang Xuan , Sun Rui , Ding Yuanxun , Tian Hua , Shu Gequn
Published: August 2023

The proper addition of additives to pure CO2 can improve the performance of CO2 as a working fluid. By working fluid, we mean a fluid used for the CO2-based transcritical power cycle characterized by the addition of R134a to CO2. Hence, an experimental investigation of the pressure drop characteristics of a supercritical CO2/R134a mixture in a rectangular microchannel was conducted. For this purpose, an accurate and stable CO2/R134a mixture thermal-hydraulic experimental system was designed and built. The experimental results show that the pressure drop of the CO2/R134a mixture is lower than that of pure CO2 under the same conditions. The proportion of friction resistance to the total pressure drop decreases with an increase in R134a composition. Finally, a frictional resistance correlation that fully considers the effects of CO2/R134a mixture components and thermophysical property variations is proposed, which can guide the design of mixture heat transfer devices.
Sputtering of amorphous Si by low-energy Ar+, Kr+, and Xe+ ions
Authors: Shibanov D. R. , Lopaev D. V. , Zyryanov S. M. , Zotovich A. I. , Maslakov K. I. , Rakhimov A. T.
Published: August 2023

Atomic layer plasma technologies require localizing ions' impact within nanometers up to an atomic layer. The possible way to achieve this is the decrease in the ion energy up to surface binding energy. At such low ion kinetic energies, the impact of different plasma effects, causing the surface modification, can be of the same order as kinetic ones. In this work, we studied the sputtering of amorphous silicon films by Ar+, Kr+, and Xe+ ions at energies of 20–200 eV under the low-pressure inductively coupled plasma discharge in pure argon, krypton, and xenon, respectively, at a plasma density of 1–1.5 × 1010 cm−3. Under the plasma conditions, a high asymmetry of discharge allowed to form ion flux energy distribution functions with narrow energy peak (5 ± 2 eV full width at half maximum). Real time in situ control over the ion composition and flux as well as the sputtering rate (the ratio of the film thickness change to the sputtering time) provided accurate determination of the sputtering yields Y(Ei). It is shown that at ion energy above ∼70 eV, the “classical” kinetic sputtering mechanism prevails. In this case, Y(Ei) grows rather rapidly with ion energy, increasing with the decrease in the ion mass: the closer the ion mass to the target atom mass, the higher the Y(Ei). Below 70 eV, the growth of Y(Ei) strongly slows down, with Y(20eV) being still high (>10−3), indicating the impact of plasma. The obtained trends of Y(Ei) are discussed in light of surface modification studied by atomic force microscopy and angular x-ray photoelectronic spectroscopy.
A multiplier-free Rulkov neuron under memristive electromagnetic induction: Dynamics analysis, energy calculation, and circuit implementation
Authors: Zhang Shaohua , Wang Cong , Zhang Hongli , Lin Hairong
Published: August 2023

Establishing a realistic and multiplier-free implemented biological neuron model is significant for recognizing and understanding natural firing behaviors, as well as advancing the integration of neuromorphic circuits. Importantly, memristors play a crucial role in constructing memristive neuron and network models by simulating synapses or electromagnetic induction. However, existing models lack the consideration of initial-boosted extreme multistability and its associated energy analysis. To this end, we propose a multiplier-free implementation of the Rulkov neuron model and utilize a periodic memristor to represent the electromagnetic induction effect, thereby achieving the biomimetic modeling of the non-autonomous memristive Rulkov (mRulkov) neuron. First, theoretical analysis demonstrates that the stability distribution of the time-varying line equilibrium point is determined by both the parameters and the memristor’s initial condition. Furthermore, numerical simulations show that the mRulkov neuron can exhibit parameter-dependent local spiking, local hidden spiking, and periodic bursting firing behaviors. In addition, based on the periodic characteristics of the memductance function, the topological invariance of the mRulkov neuron is comprehensively proved. Therefore, local basins of attraction, bifurcation diagrams, and attractors related to extreme multistability can be boosted by switching the memristor’s initial condition. Significantly, the novel boosted extreme multistability is discovered in the Rulkov neuron for the first time. More importantly, the energy transition associated with the boosting dynamics is revealed through computing the Hamilton energy distribution. Finally, we develop a simulation circuit for the non-autonomous mRulkov neuron and confirm the effectiveness of the multiplier-free implementation and the accuracy of the numerical results through PSpice simulations.
Three-dimensional mixed boiling: A strategy for critical heat flux enhancement
Authors: Wang Hao , Guan Dongxue , Ji Xianbing , Xu Jinliang
Published: August 2023

To improve the critical heat flux (CHF) in boiling heat transfer, an idea of triggering three-dimensional mixed boiling was proposed, and the corresponding surface with an extended thin film (ETFS) was designed by adding a film structure on the plain surface (PS). With ethanol as working fluid, experiments were conducted to explore mixed boiling heat transfer and CHF enhancement mechanisms on ETFS. The results demonstrate that ETFS induces spatially uneven temperatures on the boiling surface, which triggered mixing boiling in the spatial dimension—the coexistence of nucleate and film boiling—leading to a significant CHF enhancement. Nucleate boiling in the falling liquid along the extended surface is the key to stabilizing the surface temperature during the formation of dry spots on the base surface. Compared with PS and the traditional pin–fin surface, ETFS increased CHF by approximately 110% and 45%, respectively. Analysis indicated that mutual interference between nucleate boiling and film boiling effectively inhibits heat transfer deterioration caused by the deactivation of nucleating points. Through decoupling analysis of the mutual interference process in mixed boiling, it is shown that at heights of 2.0, 4.0, 6.0, and 8.0 mm, the contributions of extended film to total heat transfer are 12%, 64%, 37%, and 24%, respectively, indicating an optimal extended film height of 4.0 mm for maximum boiling heat transfer performance. This novel boiling surface with extended film structure not only improves CHF, but also reduces design costs, offering valuable guidance for radiator design purposes.
Visual experiments of bottom water and multi-well water and gas injection flooding for fault-controlled fractured-vuggy reservoirs
Authors: Guo Wanjiang , Huang Zhaoqin , Li Aifen , An Guoqiang , Cui Shiti
Published: August 2023

For fault-controlled fractured-vuggy reservoirs, the development characteristics of bottom water flooding and water and gas injection flooding under multi-well conditions must be clarified due to the structural complexity. To address this issue, we designed and manufactured fault-controlled physical experimental models based on the geological model of Tarim Oilfield and conducted flooding experiments. The results demonstrate significant variations in bottom water flooding characteristics due to differences in flow capacity within fractures, cavity area in caves, and filled area in caves under different filling modes. Different bottom water rates exhibit varying abilities to overcome gravity and breakthrough capillary resistance, significantly impacting the bottom water flooding characteristics. During the bottom water flooding period, the positioning of production wells primarily affects the macroscopic sweep range, while the filling modes significantly influence the distribution of remaining oil within individual caves. Throughout the three periods of multi-well water and gas injection, the early water injection stage mainly focuses on mobilizing “insufficiently controlled remaining oil” and some “attic remaining oil,” and the middle gas injection stage primarily targets the attic remaining oil. Finally, the late water injection stage aims to lift the oil–gas–water interface and improve oil displacement efficiency. Furthermore, different water and gas flooding directions affect displacement resistance in each channel and the longitudinal sweep range. This paper identifies the direction for the life cycle production of fault-controlled fractured-vuggy reservoirs and presents a mechanistic explanation.
Effects of blade-tip squealer geometry on the working performance of a helico-axial multi-phase pump
Authors: Huang Zongliu , Li Ye , Shi Guangtai , Tang Wanqi , Lv Wenjuan , Fu Jie
Published: August 2023

Tip-leakage flow occurs in the tip-clearance region of helico-axial multi-phase pumps, and this reduces their working performance. In this study, a structural modification, in the form of the inclusion of “squealers” on the impeller blade tips, was adopted to reduce the tip-leakage flow in a helico-axial multi-phase pump, thereby improving its working performance. Numerical simulations were conducted to examine the impact patterns of geometric parameters such as the depth, shape, and size of the squealer on the external characteristics and tip-leakage flow. The results of this study show that the presence of squealer tips has significant effect on the performance of a multi-phase pump. The depth of the squealer and the ratio of the squealer length to the blade-tip length were found to be the critical structural parameters of the squealer. There is an optimal value for the relative squealer depth, and this was found to be 9%. Larger ratios of squealer length to blade-tip length were also found to be more favorable for improving the performance of the multi-phase pump. The width and location of the squealer were found to have relatively low impacts on the performance of the multi-phase pump considered in this study. The presence of squealer reduced the tip-leakage flow rate and also alter the structure of the flow field in the impeller blade-tip region, changing the periodic distribution pattern of tip-leakage flow to some extent. The results of this study have important guiding significance for improving the performance of helico-axial multi-phase pumps.
Translating aspects of The National Rural and Remote Nursing Generalist Framework 2023–2027 into practice: opportunities and considerations
Authors: Beks H. , Clayden S. , Versace V. L.
Published: August 2023

Reforms that grow the capabilities of the health workforce are critical to improving outcomes for populations residing in rural and remote areas of Australia. Nurses are central to improving the accessibility of health care for populations in these areas. The Australian Government’s recent release of The National Rural and Remote Nursing Generalist Framework 2023–2027 is timely for identifying opportunities to strengthen the rural and remote nursing workforce. Further consideration of how the nursing workforce can be supported to translate aspects of the framework into practice is required. To achieve this, it is necessary to identify strategies to support registered nurses to develop capabilities stipulated within the framework. A logical vehicle for this translation is through the continued support of the Australian Government’s Rural Health Multidisciplinary Training program, which includes an established network of 19 University Departments of Rural Health. Leveraging from this national network that is geographically expansive and has a long-term strategic impetus for growing the rural and remote nursing workforce, provides an opportunity for translating aspects of the framework at a national scale.
An observation-based, reduced-form model for oxidation in the remote marine troposphere
Authors: Baublitz Colleen B. , Fiore Arlene M. , Ludwig Sarah M. , Nicely Julie M. , Wolfe Glenn M. , Murray Lee T. , Commane Róisín , Prather Michael J. , Anderson Daniel C. , Correa Gustavo , Duncan Bryan N. , Follette-Cook Melanie , Westervelt Daniel M. , Bourgeois Ilann , Brune William H. , Bui T. Paul , DiGangi Joshua P. , Diskin Glenn S. , Hall Samuel R. , McKain Kathryn , Miller David O. , Peischl Jeff , Thames Alexander B. , Thompson Chelsea R. , Ullmann Kirk , Wofsy Steven C.
Published: August 2023

The hydroxyl radical (OH) fuels atmospheric chemical cycling as the main sink for methane and a driver of the formation and loss of many air pollutants, but direct OH observations are sparse. We develop and evaluate an observation-based proxy for short-term, spatial variations in OH (Proxy

OH

) in the remote marine troposphere using comprehensive measurements from the NASA Atmospheric Tomography (ATom) airborne campaign. Proxy

OH

is a reduced form of the OH steady-state equation representing the dominant OH production and loss pathways in the remote marine troposphere, according to box model simulations of OH constrained with ATom observations. Proxy

OH

comprises only eight variables that are generally observed by routine ground- or satellite-based instruments. Proxy

OH

scales linearly with in situ [OH] spatial variations along the ATom flight tracks (median
r
2
= 0.90, interquartile range = 0.80 to 0.94 across 2-km altitude by 20° latitudinal regions). We deconstruct spatial variations in Proxy

OH

as a first-order approximation of the sensitivity of OH variations to individual terms. Two terms modulate within-region Proxy

OH

variations—water vapor (H
2
O) and, to a lesser extent, nitric oxide (NO). This implies that a limited set of observations could offer an avenue for observation-based mapping of OH spatial variations over much of the remote marine troposphere. Both H
2
O and NO are expected to change with climate, while NO also varies strongly with human activities. We also illustrate the utility of Proxy

OH

as a process-based approach for evaluating intermodel differences in remote marine tropospheric OH.
Electron transport chains as a window into the earliest stages of evolution
Authors: Goldman Aaron D. , Weber Jessica M. , LaRowe Douglas E. , Barge Laura M.
Published: August 2023

The origin and early evolution of life is generally studied under two different paradigms: bottom up and top down. Prebiotic chemistry and early Earth geochemistry allow researchers to explore possible origin of life scenarios. But for these “bottom–up” approaches, even successful experiments only amount to a proof of principle. On the other hand, “top–down” research on early evolutionary history is able to provide a historical account about ancient organisms, but is unable to investigate stages that occurred during and just after the origin of life. Here, we consider ancient electron transport chains (ETCs) as a potential bridge between early evolutionary history and a protocellular stage that preceded it. Current phylogenetic evidence suggests that ancestors of several extant ETC components were present at least as late as the last universal common ancestor of life. In addition, recent experiments have shown that some aspects of modern ETCs can be replicated by minerals, protocells, or organic cofactors in the absence of biological proteins. Here, we discuss the diversity of ETCs and other forms of chemiosmotic energy conservation, describe current work on the early evolution of membrane bioenergetics, and advocate for several lines of research to enhance this understanding by pairing top–down and bottom–up approaches.
The autophagy machinery interacts with EBV capsids during viral envelope release
Authors: Pena-Francesch Maria , Vanoaica Liliana Danusia , Zhu Gao-Feng , Stumpe Michael , Sankar Devanarayanan Siva , Nowag Heike , Valencia-Camargo Alma Delia , Hammerschmidt Wolfgang , Dengjel Jörn , Ligeon Laure-Anne , Münz Christian
Published: August 2023

Autophagy serves as a defense mechanism against intracellular pathogens, but several microorganisms exploit it for their own benefit. Accordingly, certain herpesviruses include autophagic membranes into their infectious virus particles. In this study, we analyzed the composition of purified virions of the Epstein–Barr virus (EBV), a common oncogenic γ-herpesvirus. In these, we found several components of the autophagy machinery, including membrane-associated LC3B-II, and numerous viral proteins, such as the capsid assembly proteins BVRF2 and BdRF1. Additionally, we showed that BVRF2 and BdRF1 interact with LC3B-II via their common protein domain. Using an EBV mutant, we identified BVRF2 as essential to assemble mature capsids and produce infectious EBV. However, BdRF1 was sufficient for the release of noninfectious viral envelopes as long as autophagy was not compromised. These data suggest that BVRF2 and BdRF1 are not only important for capsid assembly but together with the LC3B conjugation complex of ATG5-ATG12-ATG15L1 are also critical for EBV envelope release.
Identification and characterization of topoisomerase III beta poisons
Authors: Wang Wenjie , Saha Sourav , Yang Xi , Pommier Yves , Huang Shar-yin N.
Published: August 2023

We designed and carried out a high-throughput screen for compounds that trap topoisomerase III beta (TOP3B poisons) by developing a Comparative Cellular Cytotoxicity Screen. We found a bisacridine compound NSC690634 and a thiacyanine compound NSC96932 that preferentially sensitize cell lines expressing TOP3B, indicating that they target TOP3B. These compounds trap TOP3B cleavage complex (TOP3Bcc) in cells and in vitro and predominately act on RNA, leading to high levels of RNA-TOP3Bccs. NSC690634 also leads to enhanced R-loops in a TOP3B-dependent manner. Preliminary structural activity studies show that the lengths of linkers between the two aromatic moieties in each compound are critical; altering the linker length completely abolishes the trapping of TOP3Bccs. Both of our lead compounds share a similar structural motif, which can serve as a base for further modification. They may also serve in anticancer, antiviral, and/or basic research applications.
Cross-presenting Langerhans cells are required for the early reactivation of resident CD8
+
memory T cells in the epidermis
Authors: Kamenjarin Nadine , Hodapp Katrin , Melchior Felix , Harms Gregory , Hartmann Ann-Kathrin , Bartneck Joschka , Muth Sabine , Raker Verena K. , Becker Christian , Brand Anna , Clausen Björn E. , Radsak Markus P. , Schild Hansjörg , Probst Hans Christian
Published: August 2023

Tissue-resident memory CD8
+
T cells (T
RM
) reside at sites of previous infection, providing protection against reinfection with the same pathogen. In the skin, T
RM
patrol the epidermis, where keratinocytes are the entry site for many viral infections. Epidermal T
RM
react rapidly to cognate antigen encounter with the secretion of cytokines and differentiation into cytotoxic effector cells, constituting a first line of defense against skin reinfection. Despite the important protective role of skin T
RM
, it has remained unclear, whether their reactivation requires a professional antigen-presenting cell (APC). We show here, using a model system that allows antigen targeting selectively to keratinocytes in a defined area of the skin, that limited antigen expression by keratinocytes results in rapid, antigen-specific reactivation of skin T
RM
. Our data identify epidermal Langerhans cells that cross-present keratinocyte-derived antigens, as the professional APC indispensable for the early reactivation of T
RM
in the epidermal layer of the skin.
Bifurcation instructed design of multistate machines
Authors: Yang Teaya , Hathcock David , Chen Yuchao , McEuen Paul L. , Sethna James P. , Cohen Itai , Griniasty Itay
Published: August 2023

We propose a design paradigm for multistate machines where transitions from one state to another are organized by bifurcations of multiple equilibria of the energy landscape describing the collective interactions of the machine components. This design paradigm is attractive since, near bifurcations, small variations in a few control parameters can result in large changes to the system’s state providing an emergent lever mechanism. Further, the topological configuration of transitions between states near such bifurcations ensures robust operation, making the machine less sensitive to fabrication errors and noise. To design such machines, we develop and implement a new efficient algorithm that searches for interactions between the machine components that give rise to energy landscapes with these bifurcation structures. We demonstrate a proof of concept for this approach by designing magnetoelastic machines whose motions are primarily guided by their magnetic energy landscapes and show that by operating near bifurcations we can achieve multiple transition pathways between states. This proof of concept demonstration illustrates the power of this approach, which could be especially useful for soft robotics and at the microscale where typical macroscale designs are difficult to implement.
Scalable Gaussian process inference of neural responses to natural images
Authors: Goldin Matías A. , Virgili Samuele , Chalk Matthew
Published: August 2023

Predicting the responses of sensory neurons is a long-standing neuroscience goal. However, while there has been much progress in modeling neural responses to simple and/or artificial stimuli, predicting responses to natural stimuli remains an ongoing challenge. On the one hand, deep neural networks perform very well on certain datasets but can fail when data are limited. On the other hand, Gaussian processes (GPs) perform well on limited data but are poor at predicting responses to high-dimensional stimuli, such as natural images. Here, we show how structured priors, e.g., for local and smooth receptive fields, can be used to scale up GPs to model neural responses to high-dimensional stimuli. With this addition, GPs largely outperform a deep neural network trained to predict retinal responses to natural images, with the largest differences observed when both models are trained on a small dataset. Further, since they allow us to quantify the uncertainty in their predictions, GPs are well suited to closed-loop experiments, where stimuli are chosen actively so as to collect “informative” neural data. We show how GPs can be used to actively select which stimuli to present, so as to i) efficiently learn a model of retinal responses to natural images, using few data, and ii) rapidly distinguish between competing models (e.g., a linear vs. a nonlinear model). In the future, our approach could be applied to other sensory areas, beyond the retina.
RABL2 promotes the outward transition zone passage of signaling proteins in cilia via ARL3
Authors: Zhang Rui-Kai , Sun Wei-Yue , Liu Yan-Xia , Zhang Emma Y. , Fan Zhen-Chuan
Published: August 2023

Certain transmembrane and membrane-tethered signaling proteins export from cilia as BBSome cargoes via the outward BBSome transition zone (TZ) diffusion pathway, indispensable for maintaining their ciliary dynamics to enable cells to sense and transduce extracellular stimuli inside the cell. Murine Rab-like 2 (Rabl2) GTPase resemblesChlamydomonasArf-like 3 (ARL3) GTPase in promoting outward TZ passage of the signaling protein cargo-laden BBSome. During this process, ARL3 binds to and recruits the retrograde IFT train-dissociated BBSome as its effector to diffuse through the TZ for ciliary retrieval, while how RABL2 and ARL3 cross talk in this event remains uncertain. Here, we report thatChlamydomonasRABL2 in a GTP-bound form (RABL2GTP) cycles through cilia via IFT as an IFT-B1 cargo, dissociates from retrograde IFT trains at a ciliary region right above the TZ, and converts to RABL2GDPfor activating ARL3GDPas an ARL3 guanine nucleotide exchange factor. This confers ARL3GTPto detach from the ciliary membrane and become available for binding and recruiting the phospholipase D (PLD)-laden BBSome, autonomous of retrograde IFT association, to diffuse through the TZ for ciliary retrieval. Afterward, RABL2GDPexits cilia by being bound to the ARL3GTP/BBSome entity as a BBSome cargo. Our data identify ciliary signaling proteins exported from cilia via the RABL2-ARL3 cascade-mediated outward BBSome TZ diffusion pathway. According to this model, hedgehog signaling defect-induced Bardet–Biedl syndrome caused byRABL2mutations in humans could be well explained in a mutation-specific manner, providing us with a mechanistic understanding behind the outward BBSome TZ passage required for proper ciliary signaling.
Multidisciplinary learning through collective performance favors decentralization
Authors: Meluso John , Hébert-Dufresne Laurent
Published: August 2023

Many models of learning in teams assume that team members can share solutions or learn concurrently. However, these assumptions break down in multidisciplinary teams where team members often complete distinct, interrelated pieces of larger tasks. Such contexts make it difficult for individuals to separate the performance effects of their own actions from the actions of interacting neighbors. In this work, we show that individuals can overcome this challenge by learning from network neighbors through mediating artifacts (like collective performance assessments). When neighbors’ actions influence collective outcomes, teams with different networks perform relatively similarly to one another. However, varying a team’s network can affect performance on tasks that weight individuals’ contributions by network properties. Consequently, when individuals innovate (through “exploring” searches), dense networks hurt performance slightly by increasing uncertainty. In contrast, dense networks moderately help performance when individuals refine their work (through “exploiting” searches) by efficiently finding local optima. We also find that decentralization improves team performance across a battery of 34 tasks. Our results offer design principles for multidisciplinary teams within which other forms of learning prove more difficult.
Olfactory search with finite-state controllers
Authors: Verano Kyrell Vann B. , Panizon Emanuele , Celani Antonio
Published: August 2023

Long-range olfactory search is an extremely difficult task in view of the sparsity of odor signals that are available to the searcher and the complex encoding of the information about the source location. Current algorithmic approaches typically require a continuous memory space, sometimes of large dimensionality, which may hamper their optimization and often obscure their interpretation. Here, we show how finite-state controllers with a small set of discrete memory states are expressive enough to display rich, time-extended behavioral modules that resemble the ones observed in living organisms. Finite-state controllers optimized for olfactory search have an immediate interpretation in terms of approximate clocks and coarse-grained spatial maps, suggesting connections with neural models of search behavior.
Correlated surface-charging behaviors of two electrodes in an electrochemical cell
Authors: Huang Jun , Chen Yanxia , Eikerling Michael
Published: August 2023

It is revealed herein that surface-charging behaviors of the two electrodes constituting an electrochemical cell cannot be described independently by their respective electric double-layer (EDL) properties. Instead, they are correlated in such a way that the surface-charging behavior of each electrode is determined by the EDL and the reaction kinetics at both electrodes. Two fundamental equations describing the correlated surface-charging behaviors are derived, and approximate analytical solutions are obtained at low and high current densities, respectively, to facilitate transparent understanding. Important implications of the presented conceptual analysis for theoretical and computational electrochemistry are discussed. A strategy of modulating the activity of one electrode by tuning EDL parameters of the other in a two-electrode electrochemical cell is demonstrated.
Tailoring short-chain sulfur molecules to drive redox dynamics for sulfur-based aqueous battery
Authors: Miao Zhonghao , Xu Jiaxi , Xu Chiwei , Zhang Junwei , Liu Yiwen , Wanyan Boao , Yu Haoxiang , Yan Lei , Zhang Liyuan , Shu Jie
Published: August 2023

Solid–solid reactions stand out in rechargeable sulfur-based batteries due to the robust redox couples and high sulfur utilization in theory. However, conventional solid–solid reactions in sulfur cathode always present slow reaction kinetics and huge redox polarization due to the low electronic conductivity of sulfur and the generation of various electrochemical inert intermediates. In view of this, it is crucial to improve the electrochemical activity of sulfur cathode and tailor the redox direction. Guided by thermodynamics analysis, short-chain sulfur molecules (S
2-4
) are successfully synthesized by space-limited domain principle. Unlike conventional cyclic S
8
molecules with complex routes in solid–solid reaction, short-chain sulfur molecules not only shorten the length of the redox chain but also inhibit the formation of irreversible intermediates, which brings excellent redox dynamics and reversibility. As a result, the Cu-S battery built by short-chain sulfur molecules can deliver a high reversible capacity of 3,133 mAh g
−1
. To put this into practice, quasi-solid-state aqueous flexible battery based on short-chain sulfur molecules is also designed and evaluated, showing superior mechanical flexibility and electrochemical property. It indicates that the introduction of short-chain sulfur molecules in rechargeable battery can promote the development and application of high-performance sulfur-based aqueous energy storage systems.
Flexible fluid-based encapsulation platform for water-sensitive materials
Authors: Lemaire Baptiste , Yu Yanhao , Molinari Nicola , Wu Haichao , Goodwin Zachary A. H. , Stricker Friedrich , Kozinsky Boris , Aizenberg Joanna
Published: August 2023

The next-generation semiconductors and devices, such as halide perovskites and flexible electronics, are extremely sensitive to water, thus demanding highly effective protection that not only seals out water in all forms (vapor, droplet, and ice), but simultaneously provides mechanical flexibility, durability, transparency, and self-cleaning. Although various solid-state encapsulation methods have been developed, no strategy is available that can fully meet all the above requirements. Here, we report a bioinspired liquid-based encapsulation strategy that offers protection from water without sacrificing the operational properties of the encapsulated materials. Using halide perovskite as a model system, we show that damage to the perovskite from exposure to water is drastically reduced when it is coated by a polymer matrix with infused hydrophobic oil. With a combination of experimental and simulation studies, we elucidated the fundamental transport mechanisms of ultralow water transmission rate that stem from the ability of the infused liquid to fill-in and reduce defects in the coating layer, thus eliminating the low-energy diffusion pathways, and to cause water molecules to diffuse as clusters, which act together as an excellent water permeation barrier. Importantly, the presence of the liquid, as the central component in this encapsulation method provides a unique possibility of reversing the water transport direction; therefore, the lifetime of enclosed water-sensitive materials could be significantly extended via replenishing the hydrophobic oils regularly. We show that the liquid encapsulation platform presented here has high potential in providing not only water protection of the functional device but also flexibility, optical transparency, and self-healing of the coating layer, which are critical for a variety of applications, such as in perovskite solar cells and bioelectronics.
House Republicans were rewarded for supporting Donald Trump’s ‘stop the steal’ efforts
Authors: Bartels Larry M. , Carnes Nicholas
Published: August 2023

In early 2021, members of Congress cast a series of high-profile roll call votes forcing them to choose between condoning or opposing Donald Trump’s efforts to overturn the 2020 presidential election. Substantial majorities of House Republicans supported Trump, first by opposing the certification of electoral votes from Arizona and Pennsylvania on January 6th, then by opposing the president’s impeachment for inciting the attack on the US Capitol, and then by opposing a bill that would have created a national commission to investigate the events of January 6th. We examine whether the House Republicans who voted to support Trump in 2021 were rewarded or punished in the 2022 congressional midterm elections. We find no evidence that members who supported Trump did better or worse in contested general election races. However, Trump supporters were less likely to lose primary elections, more likely to run unopposed in the general election, more likely to run for higher office, and less likely to retire from politics. Overall, there seem to have been no significant political costs and some significant rewards in 2022 for House Republicans who supported Trump’s undemocratic behavior.