bluuebunny/crossref_metadata_2025 huggingface dataset:
Photostability of blue phosphorescent films on plasmonic surfaces
Authors: Carter Catrice M. , Gwynne Kelsey M. , Leil Rahma , Shen Zeqing , Cheng Zhongkai , Javed Nasir , Kumah Cindy , Bethur Eshana , Santa Dylan , Wang Chenguang D. , O’Carroll Deirdre M.
Published: April 2023

Organometallic phosphors are an important class of emissive materials used in high-efficiency organic light-emitting devices. However, problems of low photostability arise for blue-emitting phosphors due to chemical and environmental degradation and triplet quenching processes. Various approaches have been developed to improve the photostability of such phosphors, including the design of new organometallic molecules and control of host-dopant composition in thin films. Here, we demonstrate a different approach for improving the photostability of blue organometallic phosphors that uses localized surface plasmon resonances to increase the triplet recombination rate. The increased recombination rate improves the photostability of the phosphor due to the reduction in triplet quenching pathways. We show that the lifetime of phosphorescence is decreased significantly by nanoparticle-based plasmonic surfaces, which improves the photostability of the blue organometallic phosphor by up to a factor of 3.6. Other plasmonic surfaces are also tested and exhibit less significant photostability improvements due to a reduced spectral overlap of the plasmonic modes with the emitter and lower mode confinement. The use of plasmonic surfaces to improve phosphor photostability at blue wavelengths is distinct from other approaches because it involves modification to the local electromagnetic environment of the phosphor rather than modifications to the phosphor molecular structure or the emitting material composition.
Polarization enhancement in Hf0.5Zr0.5O2 capacitors induced by oxygen vacancies at elevated temperatures
Authors: Zhang Zichong , Wang Chengxu , Yang Yifan , Miao Xiangshui , Wang Xingsheng
Published: April 2023

This paper discusses a mechanism and method for polarization enhancement in fabricated Hf0.5Zr0.5O2 (HZO) capacitors. The proposed reawakening voltage operation method (RVOM) to HZO films at elevated temperatures increases the transient switching current and polarization. The change in conduction mechanisms for the HZO capacitor current after RVOM can be observed by fitting leakage current curves. The generation of oxygen vacancies (VO) by RVOM causes a rapid increase in the leakage current and a gradual degradation in the breakdown voltages of HZO capacitors. As a result, while an appropriate amount of VO generation improves the polarization, an excess will damage the reliability of HZO films. Furthermore, the augmentation of polarization does not disappear after the cooling process, which indicates that the VO as induced by RVOM does not attenuate as the temperature decreases. Our approach and the experimental results have generated ideas on how to improve the polarization of HZO films.
2.1 kV (001)-
β
-Ga2O3 vertical Schottky barrier diode with high-k oxide field plate
Authors: Roy Saurav , Bhattacharyya Arkka , Peterson Carl , Krishnamoorthy Sriram
Published: April 2023

We report a vertical β-Ga2O3 Schottky barrier diode (SBD) with BaTiO3 as field plate oxide on a low doped thick epitaxial layer exhibiting 2.1 kV breakdown voltage. A thick drift layer of 11 μm with a low effective doping concentration of 8 × 1015 cm–3 is used to achieve high breakdown voltage. Using the high-k dielectric with a dielectric constant of 248, the breakdown voltage increases from 816 V for the non-field-plated SBD to 2152 V (>2× improvement) for the field-plated SBD without compromising the on-state performance. The diode dimensions are varied to analyze the effect of edge high-field related leakage with reverse bias and also the effect of current spreading during forward operation. Very uniform distribution of breakdown voltages of 2152 ± 20 V are observed for the diode diameters from 50 to 300 μm for the field-plated SBDs. The on and off state power losses are also analyzed and compared with the non-field-plated devices and the switching losses are estimated analytically.
Approximating constant potential DFT with canonical DFT and electrostatic corrections
Authors: Domínguez-Flores Fabiola , Melander Marko M.
Published: April 2023

The complexity of electrochemical interfaces has led to the development of several approximate density functional theory (DFT)-based schemes to study reaction thermodynamics and kinetics as a function of electrode potential. While fixed electrode potential conditions can be simulated with grand canonical ensemble DFT (GCE-DFT), various electrostatic corrections on canonical, constant charge DFT are often applied instead. In this work, we present a systematic derivation and analysis of the different electrostatic corrections on canonical DFT to understand their physical validity, implicit assumptions, and scope of applicability. Our work highlights the need to carefully address the suitability of a given model for the problem under study, especially if physical or chemical insight in addition to reaction energetics is sought. In particular, we analytically show that the different corrections cannot differentiate between electrostatic interactions and covalent or charge-transfer interactions. By numerically testing different models for CO2 adsorption on a single-atom catalyst as a function of the electrode potential, we further show that computed capacitances, dipole moments, and the obtained physical insight depend sensitively on the chosen approximation. These features limit the scope, generality, and physical insight of these corrective schemes despite their proven practicality for specific systems and energetics. Finally, we suggest guidelines for choosing different electrostatic corrections and propose the use of conceptual DFT to develop more general approximations for electrochemical interfaces and reactions using canonical DFT.
Aqueous electrolyte-gated solution-processed metal oxide transistors for direct cellular interfaces
Authors: Kang Dong-Hee , Choi Jun-Gyu , Lee Won-June , Heo Dongmi , Wang Sungrok , Park Sungjun , Yoon Myung-Han
Published: April 2023

Biocompatible field-effect-transistor-based biosensors have drawn attention for the development of next-generation human-friendly electronics. High-performance electronic devices must achieve low-voltage operation, long-term operational stability, and biocompatibility. Herein, we propose an electrolyte-gated thin-film transistor made of large-area solution-processed indium–gallium–zinc oxide (IGZO) semiconductors capable of directly interacting with live cells at physiological conditions. The fabricated transistors exhibit good electrical performance operating under sub-0.5 V conditions with high on-/off-current ratios (>107) and transconductance (>1.0 mS) over an extended operational lifetime. Furthermore, we verified the biocompatibility of the IGZO surface to various types of mammalian cells in terms of cell viability, proliferation, morphology, and drug responsiveness. Finally, the prolonged stable operation of electrolyte-gated transistor devices directly integrated with live cells provides the proof-of-concept for solution-processed metal oxide material-based direct cellular interfaces.
The hidden complexity of a double-scroll attractor: Analytic proofs from a piecewise-smooth system
Authors: Belykh Vladimir N. , Barabash Nikita V. , Belykh Igor
Published: April 2023

Double-scroll attractors are one of the pillars of modern chaos theory. However, rigorous computer-free analysis of their existence and global structure is often elusive. Here, we address this fundamental problem by constructing an analytically tractable piecewise-smooth system with a double-scroll attractor. We derive a Poincaré return map to prove the existence of the double-scroll attractor and explicitly characterize its global dynamical properties. In particular, we reveal a hidden set of countably many saddle orbits associated with infinite-period Smale horseshoes. These complex hyperbolic sets emerge from an ordered iterative process that yields sequential intersections between different horseshoes and their preimages. This novel distinctive feature differs from the classical Smale horseshoes, directly intersecting with their own preimages. Our global analysis suggests that the structure of the classical Chua attractor and other figure-eight attractors might be more complex than previously thought.
Realization of superconducting transmon qubits based on topological insulator nanowires
Authors: Sun Xiaopei , Li Bing , Zhuo Enna , Lyu Zhaozheng , Ji Zhongqing , Fan Jie , Song Xiaohui , Qu Fanming , Liu Guangtong , Shen Jie , Lu Li
Published: April 2023

Topological-material-based Josephson junctions have the potential to be used to host Majorana zero modes and to construct topological qubits. For operating the topological qubits at an appropriate timescale to avoid decoherence and quasiparticle poisoning, one would eventually go to the time domain and embed the topological qubits into quantum electrodynamic circuits. Here, we constructed a topological-insulator-nanowire-based transmon qubit and demonstrated its strong coupling to a coplanar waveguide resonator. The flux-tunable spectrum and Rabi oscillations with a qubit lifetime T 1 of ∼ 0.5   μ s were observed. Such a hybrid platform, containing topological materials and quantum electrodynamic circuits, can further be used to study the physical properties such as Majorana zero modes in topological quantum circuits.
Airborne ultrasound focusing aperture with binary amplitude mask over planar ultrasound emissions
Authors: Kitano Masatake , Hasegawa Keisuke
Published: April 2023

Phased arrays of airborne ultrasound transducers are widely utilized as a key technology to achieve mid-air convergence of intense ultrasound, which is applied to a variety of systems, such as contactless tactile presentation, acoustic levitation and its application, mid-air-flow acceleration, etc. However, it requires considerably precise phase control with temporally severe synchronization between elements, which leads to difficulty in scaling up the entire system beyond the tabletop size as most of the current application systems. Here, we propose a much simpler and easier scaling-up method of airborne ultrasound convergence, where a binary amplitude mask that serves as a Fresnel Zone Plate (FZP) is placed on the planar in-phase ultrasound sources. We experimentally demonstrate that the FZP-based ultrasound focusing achieved a spatial resolution that is comparable to conventional methods, based on the use of phase-controlled transducers. The ultrasound foci created using FZPs are sufficiently intense for most application scenarios that are currently in practical use. We also determine favorable side effects of our method suppressing grating lobes, which is inevitable with the conventional phase-controlling method. The FZPs and planar ultrasound sources are both readily implemented with inexpensive ingredients and components. The result of our study contributes to upsizing dimensions in which a mid-air convergent ultrasound field is successfully generated. Accordingly, unprecedented application scenarios that target the entire room as the workspace will be possible.
Magnetic excitations in infinite-layer LaNiO2
Authors: Zhang Yajun , He Xu , Ghosez Philippe
Published: April 2023

The observation of superconductivity in infinite-layer nickelates provides an appealing new platform to explore a superconducting mechanism. Rationalizing the ground state magnetic order and spin dynamics in undoped compounds are the foundation for understanding the superconducting mechanism. Here, magnetic properties of infinite-layer LaNiO2 are investigated and compared with cuprate analog CaCuO2 by combining first-principles and spin-wave theory calculations. We reveal that LaNiO2 exhibits quasi-two-dimensional (2D) antiferromagnetic (AFM) order that mimics that of cuprate superconductors. Moreover, the electronic origin of the quasi-2D AFM state and the simulated dispersion of magnetic excitations in LaNiO2 show strong resemblance to that of NdNiO2. The establishment of a direct connection with the cuprates from the electron, orbital, and spin degrees of freedom provides solid theoretical basis to elucidate the origin of superconductivity in infinite-layer nickelates.
Enhancement of spin–flop-induced magnetic hysteresis in van der Waals magnet (Fe1−xCox)5GeTe2
Authors: Ohta Tomoharu , Kurokawa Kaito , Jiang Nan , Yamagami Kohei , Okada Yoshinori , Niimi Yasuhiro
Published: April 2023

We have systematically studied magnetotransport properties in van der Waals (vdW) magnetic materials, (Fe1−xCox)5GeTe2, where the magnetic phase changes from the ferromagnetic with the perpendicular magnetic anisotropy (PMA; x = 0 , 0.05) or with the in-plane magnetic anisotropy (IMA; x = 0.19) to the antiferromagnetic (x = 0.46) with the PMA. We have demonstrated that such magnetic properties seen in bulk still remain even in thin film devices. An anomalous Hall resistance with magnetic hysteresis was clearly observed in the low Co substitution ( x = 0 , 0.05). The anomalous Hall effect was still observable for x = 0.19, but the magnetic hysteresis vanishes because of the IMA. In the antiferromagnetic region, there was no anomalous Hall effect in the low magnetic field range, but a clear hysteresis was observed at 2.5 T where the spin–flop transition takes place. This hysteresis can be seen only below 30 K and monotonically decreases with increasing temperature. We argue that the defects at a specific site in this system and also the resistance upturn below 30 K could be related to the hysteric behavior at the spin–flop transition. Our findings provide a recipe for the use of (Fe1−xCox)5GeTe2 with different Co substitutions to construct vdW magnetic devices.
Tuning composition in graded AlGaN channel HEMTs toward improved linearity for low-noise radio-frequency amplifiers
Authors: Papamichail A. , Persson A. R. , Richter S. , Kühne P. , Stanishev V. , Persson P. O. Å. , Ferrand-Drake Del Castillo R. , Thorsell M. , Hjelmgren H. , Paskov P. P. , Rorsman N. , Darakchieva V.
Published: April 2023

Compositionally graded channel AlGaN/GaN high electron mobility transistors (HEMTs) offer a promising route to improve device linearity, which is necessary for low-noise radio-frequency amplifiers. In this work, we demonstrate different grading profiles of a 10-nm-thick AlxGa1−xN channel from x = 0 to x = 0.1 using hot-wall metal-organic chemical vapor deposition (MOCVD). The growth process is developed by optimizing the channel grading and the channel-to-barrier transition. For this purpose, the Al-profiles and the interface sharpness, as determined from scanning transmission electron microscopy combined with energy-dispersive x-ray spectroscopy, are correlated with specific MOCVD process parameters. The results are linked to the channel properties (electron density, electron mobility, and sheet resistance) obtained by contactless Hall and terahertz optical Hall effect measurements coupled with simulations from solving self-consistently Poisson and Schrödinger equations. The impact of incorporating a thin AlN interlayer between the graded channel and the barrier layer on the HEMT properties is investigated and discussed. The optimized graded channel HEMT structure is found to have similarly high electron density (∼ 9  × 10 12 cm−2) as the non-graded conventional structure, though the mobility drops from ∼ 2360 cm2/V s in the conventional to ∼ 960 cm2/V s in the graded structure. The transconductance gm of the linearly graded channel HEMTs is shown to be flatter with smaller g m ′ and g m ″ as compared to the conventional non-graded channel HEMT implying improved device linearity.
Toward droplets displaying life-like interaction behaviors
Authors: Berli Claudio L. A. , Bellino Martín G.
Published: April 2023

Developments in synthetic biology usually bring the conception of individual artificial cells. A key feature of living systems is, however, the interaction between individuals, in which living units can interact autonomously and display a role differentiation such as the case of entities chasing each other. On the other hand, droplets have become a very useful and exciting medium for modern microengineering and biomedical technologies. In this Perspective, we show a brief discussion-outlook of different approaches to recreate predator–prey interactions in both swimmer and crawling droplet systems toward a new generation of synthetic life with impact in both fundamental insights and relevant applications.
Investigation of stochastic heating and its influence on plasma radial uniformity in biased inductively coupled Ar discharges by hybrid simulation
Authors: Huang Jia-Wei , Zhao Ming-Liang , Zhang Yu-Ru , Gao Fei , Wang You-Nian
Published: April 2023

A bias power is usually applied in inductively coupled plasmas (ICP) to realize the separate control of the plasma density and the ion energy. In this research, a two-dimensional fluid/electron Monte Carlo hybrid model is developed to self-consistently investigate the bias effect on the stochastic heating and on the radial homogeneity in a biased argon ICP operated at low pressure (3 mTorr). The results show that the temporal evolution of the stochastic heating exhibits a plateau and a peak when the sheath collapses at high bias voltages, due to the limited sheath heating and the electron inertia. In addition, the plasma density in the diffusion chamber increases with bias voltage and bias frequency, because of the more pronounced stochastic heating both at the substrate and at the grounded wall. In the main discharge chamber, the plasma density decreases with bias voltage, due to the compression of the bulk plasma region, and this trend becomes less obvious at high bias frequency, because of the enhanced power absorption caused by the stochastic heating. Therefore, it is concluded that by tuning the bias voltage and bias frequency, the plasma radial uniformity could be modulated efficiently, which is very important for improving plasma processing.
Collective behavior of identical Stuart–Landau oscillators in a star network with coupling asymmetry effects
Authors: Chen XinYue , Chen Ran , Sun YiLin , Liu Shuai
Published: April 2023

In this study, we investigated the impact of the asymmetry of a coupling scheme on oscillator dynamics in a star network. We obtained stability conditions for the collective behavior of the systems, ranging from an equilibrium point over complete synchronization (CS) and quenched hub incoherence to remote synchronization states using both numerical and analytical methods. The coupling asymmetry factor α significantly influences and determines the stable parameter region of each state. For α ≠ 1, the equilibrium point can emerge when the Hopf bifurcation parameter a is positive, which is impossible for diffusive coupling. However, CS can occur even if a is negative under α < 1. Unlike diffusive coupling, we observe more behavior when α ≠ 1, including additional in-phase remote synchronization. These results are supported by theoretical analysis and validated through numerical simulations and independent of network size. The findings may offer practical methods for controlling, restoring, or obstructing specific collective behavior.
Coherent organizational states in turbulent pipe flow at moderate Reynolds numbers
Authors: Jäckel R. , Magacho B. , Owolabi B. E. , Moriconi L. , Dennis D. J. C. , Loureiro J. B. R.
Published: April 2023

Turbulent pipe flow is still an essentially open area of research, boosted in the last two decades by considerable progress achieved on both the experimental and numerical frontiers, mainly related to the identification and characterization of coherent structures as basic building blocks of turbulence. It has been a challenging task, however, to detect and visualize these coherent states. We address, by means of stereoscopic particle image velocimetry, that issue with the help of a large diameter (6 in.) pipe loop, which allowed us to probe for coherent states at various moderate Reynolds numbers (5300 < Re < 29 000) of the single-phase Newtonian flow. Although these states have been observed at flow regimes around laminar–turbulent transition (Re ≈ 2300) and also at high Reynolds number pipe flow (Re ≈ 35 000), at moderate Reynolds numbers, their existence had not been observed yet by experiment. By conditionally averaging the flow fields with respect to their dominant azimuthal wavenumber of streamwise velocity streaks, we have been able to uncover the existence of ten well-defined coherent flow patterns. It turns out, as a remarkable phenomenon, that their occurrence probabilities and the total number of dominant modes do not essentially change as the Reynolds number is varied. Their occurrence probabilities are noted to be reasonably well described by a Poisson distribution, which suggests that low-speed streaks are created as a Poisson process on the pipe circular geometry.
Natural virtual orbitals for the GW method in the random-phase approximation and beyond
Authors: Monzel Laurenz , Holzer Christof , Klopper Wim
Published: April 2023

The increasingly popular GW method is becoming a convenient tool to determine vertical ionization energies in molecular systems. However, depending on the formalism used and the range of orbitals investigated, it may be hampered by a steep computational scaling. To alleviate this issue, correlated natural virtual orbitals (NVOs) based on second-order Møller–Plesset (MP2) and direct MP2 correlation energies are implemented, and the resulting correlated NVOs are tested on GW quasiparticle energies. Test cases include the popular GW variants G0W0 and evGW0 as well as more elaborate vertex corrections. We find that for increasingly larger molecular systems and basis sets, NVOs considerably improve efficiency. Furthermore, we test the performance of the truncated (frozen) NVO ansatz on the GW100 test set. For the latter, it is demonstrated that, using a carefully chosen truncation threshold, NVOs lead to a negligible loss in accuracy while providing speedups of one order of magnitude. Furthermore, we compare the resulting quasiparticle energies to very accurate vertical ionization energies obtained from coupled-cluster theory with singles, doubles, and noniterative triples [CCSD(T)], confirming that the loss in accuracy introduced by truncating the NVOs is negligible compared to the methodical errors in the GW approximation. It is also demonstrated that the choice of basis set impacts results far more than using a suitably truncated NVO space. Therefore, at the same computational expense, more accurate results can be obtained using NVOs. Finally, we provide improved reference CCSD(T) values for the GW100 test set, which have been obtained using the def2-QZVPP basis set.
Mixed ionic-electronic transport in Na2O doped glassy electrolytes: Promising candidate for new generation sodium ion battery electrolytes
Authors: Ram Rakesh , Bhattacharya Sanjib
Published: April 2023

In the present communication, newly developed glassy electrolytes, Na2O–ZnO–CdO, have been considered to discuss their electrical transport behavior at ambient temperature. The AC conductivity and relaxation behavior of them have been studied in the light of Almond-West formalism. The electrical conductivity (mixed conduction) is found to be a function of frequency as well as temperature. In the low-frequency range, it shows a flat conductivity owing to the diffusional motion of Na+ ions, whereas at high frequency, the conductivity shows dispersion. The DC conductivity ( σ dc ) and hopping frequency have been computed from the best fitted plots of experimental data. The AC conductivity at different concentrations and a constant temperature has been reported. The variation in the conductivity data with reciprocal temperatures indicates the dynamical behavior of charge carriers via hopping conduction in sodium oxide glassy systems. Mixed conduction in the present system may be dominated by polaron hopping in the samples with a lower Na2O content with a percolation type of motion of the electron/polaron. On the other hand, three-dimensional Na+ motion is the dominating charge carrier for the samples with a higher Na2O content. A negligible small difference in pathways in the I–V characteristics in both the directions should make the present system a promising candidate for the new generation battery electrolyte.
High hole mobility and non-localized states in amorphous germanium
Authors: Tran Tuan T. , Wong-Leung Jennifer , Smillie Lachlan A. , Hallén Anders , Grimaldi Maria G. , Williams Jim S.
Published: April 2023

Covalent amorphous semiconductors, such as amorphous silicon (a-Si) and germanium (a-Ge), are commonly believed to have localized electronic states at the top of the valence band and the bottom of the conduction band. Electrical conductivity is thought to occur through the hopping mechanism via these localized states. The carrier mobility of these materials is usually very low, in the order of ∼10−3–10−2 cm2/Vs at room temperature. In this study, we show that pure high-density amorphous Ge has exceptionally high carrier mobility, in the order of ∼100 cm2/Vs, and a high hole concentration of ∼1018 cm−3. The temperature-dependent conductivity of the material is also very-well defined with two distinctive regions, extrinsic and intrinsic conductivity, as in crystalline Ge. These results provide direct evidence for a largely preserved band structure and non-localized states within the valence band in high-density amorphous Ge, as previously suggested by Tauc et al. from optical characterization alone.
Airborne disease transmission during indoor gatherings over multiple time scales: Modeling framework and policy implications
Authors: Dixit Avinash K. , Espinoza Baltazar , Qiu Zirou , Vullikanti Anil , Marathe Madhav V.
Published: April 2023

Indoor superspreading events are significant drivers of transmission of respiratory diseases. In this work, we study the dynamics of airborne transmission in consecutive meetings of individuals in enclosed spaces. In contrast to the usual pairwise-interaction models of infection where effective contacts transmit the disease, we focus on group interactions where individuals with distinct health states meet simultaneously. Specifically, the disease is transmitted by infected individuals exhaling droplets (contributing to the viral load in the closed space) and susceptible ones inhaling the contaminated air. We propose a modeling framework that couples the fast dynamics of the viral load attained over meetings in enclosed spaces and the slow dynamics of disease progression at the population level. Our modeling framework incorporates the multiple time scales involved in different setups in which indoor events may happen, from single-time events to events hosting multiple meetings per day, over many days. We present theoretical and numerical results of trade-offs between the room characteristics (ventilation system efficiency and air mass) and the group’s behavioral and composition characteristics (group size, mask compliance, testing, meeting time, and break times), that inform indoor policies to achieve disease control in closed environments through different pathways. Our results emphasize the impact of break times, mask-wearing, and testing on facilitating the conditions to achieve disease control. We study scenarios of different break times, mask compliance, and testing. We also derive policy guidelines to contain the infection rate under a certain threshold.
STAT2 hinders STING intracellular trafficking and reshapes its activation in response to DNA damage
Authors: Wang Chenyao , Nan Jing , Holvey-Bates Elise , Chen Xing , Wightman Samantha , Latif Muhammad-Bilal , Zhao Junjie , Li Xiaoxia , Sen Ganes C. , Stark George R. , Wang Yuxin
Published: April 2023

In cancer cells, endogenous or therapy-induced DNA damage leads to the abnormal presence of DNA in the cytoplasm, which triggers the activation of cGAS (cyclic GMP–AMP synthase) and STING (stimulator of interferon genes). STAT2 suppresses the cGAMP-induced expression of IRF3-dependent genes by binding to STING, blocking its intracellular trafficking, which is essential for the full response to STING activation. STAT2 reshapes STING signaling by inhibiting the induction of IRF3-dependent, but not NF-κB–dependent genes. This noncanonical activity of STAT2 is regulated independently of its tyrosine phosphorylation but does depend on the phosphorylation of threonine 404, which promotes the formation of a STAT2:STING complex that keeps STING bound to the endoplasmic reticulum (ER) and increases resistance to DNA damage. We conclude that STAT2 is a key negative intracellular regulator of STING, a function that is quite distinct from its function as a transcription factor.
Multilevel cultural evolution: From new theory to practical applications
Authors: Wilson David Sloan , Madhavan Guru , Gelfand Michele J. , Hayes Steven C. , Atkins Paul W. B. , Colwell Rita R.
Published: April 2023

Evolutionary science has led to many practical applications of genetic evolution but few practical uses of cultural evolution. This is because the entire study of evolution was gene centric for most of the 20th century, relegating the study and application of human cultural change to other disciplines. The formal study of human cultural evolution began in the 1970s and has matured to the point of deriving practical applications. We provide an overview of these developments and examples for the topic areas of complex systems science and engineering, economics and business, mental health and well-being, and global change efforts.
The Afrotropical breeding grounds of the Palearctic-African migratory painted lady butterflies (Vanessa cardui)
Authors: Talavera Gerard , García-Berro Aurora , Talla Valery N. K. , Ng’iru Ivy , Bahleman Farid , Kébé Khadim , Nzala Kelvin M. , Plasencia Dulce , Marafi Mohammad A. J. , Kassie Abeje , Goudégnon Eude O. A. , Kiki Martial , Benyamini Dubi , Reich Megan S. , López-Mañas Roger , Benetello Fulvia , Collins Steve C. , Bataille Clément P. , Pierce Naomi E. , Martins Dino J. , Suchan Tomasz , Menchetti Mattia , Vila Roger
Published: April 2023

Migratory insects are key players in ecosystem functioning and services, but their spatiotemporal distributions are typically poorly known. Ecological niche modeling (ENM) may be used to predict species seasonal distributions, but the resulting hypotheses should eventually be validated by field data. The painted lady butterfly (Vanessa cardui) performs multigenerational migrations between Europe and Africa and has become a model species for insect movement ecology. While the annual migration cycle of this species is well understood for Europe and northernmost Africa, it is still unknown where most individuals spend the winter. Through ENM, we previously predicted suitable breeding grounds in the subhumid regions near the tropics between November and February. In this work, we assess the suitability of these predictions through i) extensive field surveys and ii) two-year monitoring in six countries: a large-scale monitoring scheme to study butterfly migration in Africa. We document new breeding locations, year-round phenological information, and hostplant use. Field observations were nearly always predicted with high probability by the previous ENM, and monitoring demonstrated the influence of the precipitation seasonality regime on migratory phenology. Using the updated dataset, we built a refined ENM for the Palearctic-African range ofV. cardui. We confirm the relevance of the Afrotropical region and document the missing natural history pieces of the longest migratory cycle described in butterflies.
A genetically encoded photoproximity labeling approach for mapping protein territories
Authors: Hananya Nir , Ye Xuanjia , Koren Shany , Muir Tom W.
Published: April 2023

Studying dynamic biological processes requires approaches compatible with the lifetimes of the biochemical transactions under investigation, which can be very short. We describe a genetically encoded system that allows protein neighborhoods to be mapped using visible light. Our approach involves fusing an engineered flavoprotein to a protein of interest. Brief excitation of the fusion protein leads to the labeling of nearby proteins with cell-permeable probes. Mechanistic studies reveal different labeling pathways are operational depending on the nature of the exogenous probe that is employed. When combined with quantitative proteomics, this photoproximity labeling system generates “snapshots” of protein territories with high temporal and spatial resolution. The intrinsic fluorescence of the fusion domain permits correlated imaging and proteomics analyses, a capability that is exploited in several contexts, including defining the protein clients of the major vault protein. The technology should be broadly useful in the biomedical area.
Interrogating bromodomain inhibitor resistance in KMT2A-rearranged leukemia through combinatorial CRISPR screens
Authors: Wright Shaela , Hu Jianzhong , Wang Hong , Hyle Judith , Zhang Yang , Du Guoqing , Konopleva Marina Y. , Kornblau Steven M. , Djekidel Mohamed Nadhir , Rosikiewicz Wojciech , Xu Beisi , Lu Rui , Yang Jun J. , Li Chunliang
Published: April 2023

Bromo- and extra-terminal domain inhibitors (BETi) have exhibited therapeutic activities in many cancers. However, the mechanisms controlling BETi response and resistance are not well understood. We conducted genome-wide loss-of-function CRISPR screens using BETi-treated KMT2A-rearranged (KMT2A-r) cell lines. We revealed that
Speckle-type POZ protein (SPOP)
gene (Speckle Type BTB/POZ Protein) deficiency caused significant BETi resistance, which was further validated in cell lines and xenograft models. Proteomics analysis and a kinase-vulnerability CRISPR screen indicated that cells treated with BETi are sensitive to GSK3 perturbation. Pharmaceutical inhibition of GSK3 reversed the BETi-resistance phenotype. Based on this observation, a combination therapy regimen inhibiting both BET and GSK3 was developed to impede KMT2A-r leukemia progression in patient-derived xenografts in vivo. Our results revealed molecular mechanisms underlying BETi resistance and a promising combination treatment regimen of ABBV-744 and CHIR-98014 by utilizing unique ex vivo and in vivo KMT2A-r PDX models.
Derepression of Y-linked multicopy protamine-like genes interferes with sperm nuclear compaction in
D. melanogaster
Authors: Park Jun I. , Bell George W. , Yamashita Yukiko M.
Published: April 2023

Across species, sperm maturation involves the dramatic reconfiguration of chromatin into highly compact nuclei that enhance hydrodynamic ability and ensure paternal genomic integrity. This process is mediated by the replacement of histones by sperm nuclear basic proteins, also referred to as protamines. In humans, a carefully balanced dosage between two known protamine genes is required for optimal fertility. However, it remains unknown how their proper balance is regulated and how defects in balance may lead to compromised fertility. Here, we show that a nucleolar protein,
modulo
, a homolog of
nucleolin
, mediates the histone-to-protamine transition during
Drosophila
spermatogenesis. We find that
modulo
mutants display nuclear compaction defects during late spermatogenesis due to decreased expression of autosomal protamine genes (including
Mst77F
) and derepression of Y-linked multicopy
Mst77F
homologs (
Mst77Y
), leading to the mutant’s known sterility. Overexpression of
Mst77Y
in a wild-type background is sufficient to cause nuclear compaction defects, similar to
modulo
mutant, indicating that Mst77Y is a dominant-negative variant interfering with the process of histone-to-protamine transition. Interestingly, ectopic overexpression of
Mst77Y
caused decompaction of X-bearing spermatids nuclei more frequently than Y-bearing spermatid nuclei, although this did not greatly affect the sex ratio of offspring. We further show that
modulo
regulates these protamine genes at the step of transcript polyadenylation. We conclude that the regulation of protamines mediated by
modulo
, ensuring the expression of functional ones while repressing dominant-negative ones, is critical for male fertility.
Large-scale invasion of unicellular eukaryotic genomes by integrating DNA viruses
Authors: Bellas Christopher , Hackl Thomas , Plakolb Marie-Sophie , Koslová Anna , Fischer Matthias G. , Sommaruga Ruben
Published: April 2023

Eukaryotic genomes contain a variety of endogenous viral elements (EVEs), which are mostly derived from RNA and ssDNA viruses that are no longer functional and are considered to be “genomic fossils.” Genomic surveys of EVEs, however, are strongly biased toward animals and plants, whereas protists, which represent the majority of eukaryotic diversity, remain poorly represented. Here, we show that protist genomes harbor tens to thousands of diverse, ~14 to 40 kbp long dsDNA viruses. These EVEs, composed of virophages, Polinton-like viruses, and related entities, have remained hitherto hidden owing to poor sequence conservation between virus groups and their repetitive nature that precluded accurate short-read assembly. We show that long-read sequencing technology is ideal for resolving virus insertions. Many protist EVEs appear intact, and most encode integrases, which suggests that they have actively colonized hosts across the tree of eukaryotes. We also found evidence for gene expression in host transcriptomes and that closely related virophage and Polinton-like virus genomes are abundant in viral metagenomes, indicating that many EVEs are probably functional viruses.
A spatially resolved elemental nanodomain organization within acidocalcisomes in
Trypanosoma cruzi
Authors: Girard-Dias Wendell , Augusto Ingrid , V. A. Fernandes Tácio , G. Pascutti Pedro , de Souza Wanderley , Miranda Kildare
Published: April 2023

How are ions distributed in the three-dimensional (3D) volume confined in a nanoscale compartment? Regulation of ionic flow in the intracellular milieu has been explained by different theoretical models and experimentally demonstrated for several compartments with microscale dimensions. Most of these models predict a homogeneous distribution of ions seconds or milliseconds after an initial diffusion step formed at the ion translocation site, leaving open questions when it comes to ion/element distribution in spaces/compartments with nanoscale dimensions. Due to the influence of compartment size on the regulation of ionic flow, theoretical variations of classical models have been proposed, suggesting heterogeneous distributions of ions/elements within nanoscale compartments. Nonetheless, such assumptions have not been fully proven for the 3D volume of an organelle. In this work, we used a combination of cutting-edge electron microscopy techniques to map the 3D distribution of diffusible elements within the whole volume of acidocalcisomes in trypanosomes. Cryofixed cells were analyzed by scanning transmission electron microscopy tomography combined with elemental mapping using a high-performance setup of X-ray detectors. Results showed the existence of elemental nanodomains within the acidocalcisomes, where cationic elements display a self-excluding pattern. These were validated by Pearson correlation analysis and in silico molecular dynamic simulations. Formation of element domains within the 3D space of an organelle is demonstrated. Distribution patterns that support the electrodiffusion theory proposed for nanophysiology models have been found. The experimental pipeline shown here can be applied to a variety of models where ion mobilization plays a crucial role in physiological processes.
Making ammonia from nitrogen and water microdroplets
Authors: Song Xiaowei , Basheer Chanbasha , Zare Richard N.
Published: April 2023

Water (H
2
O) microdroplets are sprayed onto a magnetic iron oxide (Fe
3
O
4
) and Nafion-coated graphite mesh using compressed N
2
or air as the nebulizing gas. The resulting splash of microdroplets enters a mass spectrometer and is found to contain ammonia (NH
3
). This gas–liquid–solid heterogeneous catalytic system synthesizes ammonia in 0.2 ms. The conversion rate reaches 32.9 ± 1.38 nmol s
−1
cm
−2
at room temperature without application of an external electric potential and without irradiation. Water microdroplets are the hydrogen source for N
2
in contact with Fe
3
O
4
. Hydrazine (H
2
NNH
2
) is also observed as a by-product and is suspected to be an intermediate in the formation of ammonia. This one-step nitrogen-fixation strategy to produce ammonia is eco-friendly and low cost, which converts widely available starting materials into a value-added product.
HY5 functions as a systemic signal by integrating BRC1-dependent hormone signaling in tomato bud outgrowth
Authors: Dong Han , Wang Jiachun , Song Xuewei , Hu Chaoyi , Zhu Changan , Sun Ting , Zhou Zhiwen , Hu Zhangjian , Xia Xiaojian , Zhou Jie , Shi Kai , Zhou Yanhong , Foyer Christine H. , Yu Jingquan
Published: April 2023

Light plays an important role in determining plant architecture, which greatly influences crop yield. However, the precise mechanisms by which light signaling regulates bud outgrowth remain to be identified. Here, we show that light regulates bud outgrowth via both HY5 and brassinosteroid (BR)-dependent pathways in tomato. Inactivation of the red-light photoreceptor PHYB, or deficiencies in PHYB or the blue-light photoreceptor CRY1a, inhibits bud outgrowth and leads to decreased accumulation of HY5 protein and increased transcript level of
BRANCHED1
(
BRC1
), a central integrator of branching signals. HY5, functioning as a mobile systemic signal from leaves, promotes bud outgrowth by directly suppressing
BRC1
transcript and activating the transcript of BR biosynthesis genes within the lateral buds in tomato. Furthermore, BRC1 prevents the accumulation of cytokinin (CK) and gibberellin (GA) by directly inhibiting the transcript of CK synthesis gene
LOG4
, while increasing the transcript levels of CK and GA degradation genes (
CKX7
,
GA2ox4
, and
GA2ox5
), leading to an arrest of bud outgrowth. Moreover, bud outgrowth occurs predominantly in the day due to the suppression of
BRC1
transcript by HY5. These findings demonstrate that light-inducible HY5 acts as a systemic signaling factor in fine-tuning the bud outgrowth of tomato.
RFWD3 promotes ZRANB3 recruitment to regulate the remodeling of stalled replication forks
Authors: Moore Chandler E. , Yalcindag Selin E. , Czeladko Hanna , Ravindranathan Ramya , Wijesekara Hanthi Yodhara , Levy Juliana C. , Sannino Vincenzo , Schindler Detlev , Ciccia Alberto , Costanzo Vincenzo , Elia Andrew E.H.
Published: April 2023

Replication fork reversal is an important mechanism to protect the stability of stalled forks and thereby preserve genomic integrity. While multiple enzymes have been identified that can remodel forks, their regulation remains poorly understood. Here, we demonstrate that the ubiquitin ligase RFWD3, whose mutation causes Fanconi Anemia, promotes recruitment of the DNA translocase ZRANB3 to stalled replication forks and ubiquitinated sites of DNA damage. Using electron microscopy, we show that RFWD3 stimulates fork remodeling in a ZRANB3-epistatic manner. Fork reversal is known to promote nascent DNA degradation in BRCA2-deficient cells. Consistent with a role for RFWD3 in fork reversal, inactivation of RFWD3 in these cells rescues fork degradation and collapse, analogous to ZRANB3 inactivation. RFWD3 loss impairs ZRANB3 localization to spontaneous nuclear foci induced by inhibition of the PCNA deubiquitinase USP1. We demonstrate that RFWD3 promotes PCNA ubiquitination and interaction with ZRANB3, providing a mechanism for RFWD3-dependent recruitment of ZRANB3. Together, these results uncover a new role for RFWD3 in regulating ZRANB3-dependent fork remodeling.
Functional specialization of short-lived and long-lived macrophage subsets in human tonsils
Authors: Alaoui Lamine , Villar Javiera , Leclere Renaud , Le Gallou Simon , Relouzat Francis , Michaud Henri-Alexandre , Tarte Karin , Teissier Natacha , Favier Benoît , Roussel Mikaël , Segura Elodie
Published: April 2023

Macrophages play a central role in tissue homeostasis and host defense. However, the properties of human macrophages in non-diseased tissues remain poorly understood. Here, we characterized human tonsil macrophages and identified three subsets with distinct phenotype, transcriptome, life cycle, and function. CD36hi macrophages were related to monocytes, while CD36lo macrophages showed features of embryonic origin and CD36int macrophages had a mixed profile. scRNA-seq on non-human primate tonsils showed that monocyte recruitment did not pre-exist an immune challenge. Functionally, CD36hi macrophages were specialized for stimulating T follicular helper cells, by producing Activin A. Combining reconstruction of ligand–receptor interactions and functional assays, we identified stromal cell–derived TNF-α as an inducer of Activin A secretion. However, only CD36hi macrophages were primed for Activin A expression, via the activity of IRF1. Our results provide insight into the heterogeneity of human lymphoid organ macrophages and show that tonsil CD36hi macrophage specialization is the result of both intrinsic features and interaction with stromal cells.
Quantum Optical Description of Radiation by a Two-Level System in Strong Laser Fields
Authors: Peng Zhaoyang , Hu Huayu , Zhao Zengxiu , Yuan Jianmin
Published: April 2023

We develop a quantum optical description of radiation from a two-level system (TLS) in strong laser fields, which provides a clear insight into the final states of the TLS and the harmonics field. It is shown that there are two emission channels: the Rayleigh-like channel and the Raman-like channel, which correspond to the TLS ending up in the ground state and excited state after the emission, respectively. The numerical result shows that the harmonics are mainly produced by the Rayleigh-like channel. In addition, according to the coherence of emission among the emitters, the radiation is divided into coherent parts that result from the semi-classical dipole oscillation and incoherent parts that result from the quantum fluctuations of the dipole moment. In the weak field limits, the Rayleigh-like channel corresponds to the coherent parts, and the Raman-like channel corresponds to the incoherent parts. However, in strong laser fields, both channels contribute to coherent and incoherent radiation, and how much they contribute depends on the final excitation. By manipulating the laser field, we can make the Rayleigh-like channel produce either coherent or incoherent radiation.
Multimaterial 4D printing with a tunable bending model
Authors: Zolfagharian Ali , Jarrah Hamid Reza , S Xavier Matheus , Rolfe Bernard , Bodaghi Mahdi
Published: April 2023

Shape-memory polymer (SMP)-based functional structures may now be produced more efficiently via four-dimensional (4D) printing, benefiting from the recent advances in multi-material three-dimensional printing technologies. Composite material design using 4D printing has opened new possibilities for customizing the shape memory property of smart polymers. This work studies a design strategy to harness desirable morphing by 4D printing multimaterial composites with a focus on the detailed finite element (FE) procedure, experimental results, and soft robotic application. Composites with bilayer laminates consisting of a SMP and a flexible elastomer are constructed with variable thickness ratios to control the self-bending of the composite. FE simulations are used to understand the underlying processes of composite materials and to generate accurate predictions for the experimental results, which reduces cost and development time. The application of 4D printing and multi-material composite programming is demonstrated with a soft robotic gripper for manipulating fragile objects.