bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Er atoms on graphitization process and structural defects for epitaxial graphene
Authors: Duan Yong , Kong Wenxia , Zhang Jinzhe , Wang Jianxin , Cai Qun
Published: October 2022

Thermal decomposition of SiC at high temperature usually brings about excessively fast Si sublimation and a very rough surface. In order to fabricate high-quality homogeneous epitaxial graphene on a SiC(0001) substrate, highly reactive erbium atoms are employed in this work. Scanning tunneling microscopy and Raman spectroscopy have been utilized to investigate the modulations of Er atoms on graphitization evolution and structural defects for graphene after annealing durations. Experimental results show that Er atoms pre-deposited on clean substrates can definitely enhance the surface graphitization of SiC and make graphene grow in a controllable way. The existence of Er layer is believed to break Si–C bonds at low temperature and to decrease the Si sublimate rate. It is also demonstrated that Er atoms can modify the type of structural defects in graphene, and the areal density of flower defects increases to 1.22 × 1012 cm−2, quadrupling that in pristine graphene. This work puts forward a fabrication method for epitaxial graphene with flower defects in high density and will enlighten some future applications of graphene in nanoelectronics, electron energy filtering, and chemical catalysis.
InSn plasma penetration through protective single-walled carbon nanotube-based membranes
Authors: Gubarev V. , Krivokorytov M. , Ramirez Benavides J. A. , Krivtsun V. , Ivanov V. , Medvedev V. , Pal A. , Krasnikov D. , Nasibulin A.
Published: October 2022

Laser-produced plasma sources of short-wavelength (1–20-nm) radiation are actively used nowadays in numerous applications, including water-window microscopy and extreme ultra-violet lithography. Suppression of laser-plasma debris (responsible for damaging optics) is crucial for the lifetime prolongation of optical systems operated with the short-wavelength radiation. Here, we examine the capability of single-walled carbon nanotube (SWCNT)-based membranes to decrease an InSn plasma flux containing both ions and atoms. Faraday cup measurements show that 40- and 90-nm-thick SWCNT membranes reduce the total charge transition by 20 and 130 times, respectively. The ion analyzer measurements demonstrate that ions pass through the membrane mainly due to the collisionless (ballistic) mechanism. Using scanning electron microscopy, we estimate a decrease in a plasma (ions + atoms) flux to be of 18 and 140 times for 40- and 90-nm-thick SWCNT-based membranes, respectively. The average plasma flux attenuation coefficient of SWCNT membranes is calculated as k = 0.063 nm−1.
Design and optimization of two-degree-of-freedom parallel four pure-slide- and four parallel quadrilateral-pair precision positioning platform
Authors: Ji Hua-Wei , Lv Bo , Li Tian-Yi , Yang Fan , Qi An-Qi , Wu Xin , Ni Jing
Published: October 2022

Aiming at the complex structure, small output displacement, and low positioning accuracy of the two-degree-of-freedom (2-DOF) precision positioning platform, theoretical analyses and experimental tests are carried out so that the platform has the characteristics of compact structure, large output stroke, and high positioning accuracy. First, to optimize the structural parameters of the positioning platform, a modeling method to improve the modeling accuracy of the compliant mechanism of the positioning platform is proposed. A static model of the positioning platform based on Euler–Bernoulli beam theory and the sixth-order compliance matrix method is established, and the accuracy of the model is verified by simulation. In addition, the single-objective genetic optimization algorithm is used to optimize the structural size parameters of the positioning platform, and the optimal solution set of the structural size parameters of the positioning platform is obtained by taking the displacement amplification rate of the positioning platform as the optimization target. Finally, according to theoretical and simulation analysis and optimization results, an experimental prototype was fabricated, and a series of experimental tests were carried out on the working stroke, displacement magnification, and output stiffness. The experimental results show that the displacement magnification of the positioning platform reaches 3.39, the positioning stroke is 89.2 × 85.9 µm2, and the displacement resolutions of the x-axis and y-axis are 35 and 31 nm, respectively. The positioning platform designed in this paper meets the requirements of large output stroke and high positioning accuracy.
Four-field Hamiltonian fluid closures of the one-dimensional Vlasov–Poisson equation
Authors: Chandre C. , Shadwick B. A.
Published: October 2022

We consider a reduced dynamics for the first four fluid moments of the one-dimensional Vlasov–Poisson equation, namely, fluid density, fluid velocity, pressure, and heat flux. This dynamics depends on an equation of state to close the system. This equation of state (closure) connects the fifth-order moment—related to the kurtosis in velocity of the Vlasov distribution—with the first four moments. By solving the Jacobi identity, we derive an equation of state, which ensures that the resulting reduced fluid model is Hamiltonian. We show that this Hamiltonian closure allows symmetric homogeneous equilibria of the reduced fluid model to be stable.
An analytical model for a multilayer elastocaloric cooling regenerator
Authors: Huang Chaiyi , Liang Jierong , Liu Zhe , Li Tingxun
Published: October 2022

Layering elastocaloric materials can effectively maximize the average elastocaloric effect along the regenerator with a temperature gradient. An explicit correlation for mapping the performance of the layering elastocaloric regenerator from design parameters was developed by simplifying elastocaloric material property and energy conservation equations. Cooling capacity and coefficient of performance are found to be theoretically inversely linear with temperature span when the nonlinear dependence of elastocaloric heat on temperature is disregarded. The optimum utilization factor, the volume fraction of materials, the number of layers, and the transformation temperature spacing are obtained by confining the materials operating in the vicinity of their transformation temperatures. Performance degradation caused by hysteresis is found to be approximately linear with the hysteretic entropy change normalized by the isothermal entropy change.
High mechanical Q-factor measurement of Si using a 3D cantilever support
Authors: Hamedan V. Jaberian , Winterflood J. , Blair C. , Ju L. , Zhao C.
Published: October 2022

Thermal noise in test mass substrates and coatings is a significant noise contribution in the detection band of current and proposed future gravitational wave detectors. Substrate thermal noise can be reduced by using high mechanical Q-factor materials and cooling the test mass mirrors. Silicon is a promising potential candidate for the next generation detector test masses. The low thermal expansion and high thermal conductivity of silicon allow efficient cryogenic operation, and a significant increase in the amount of optical power that can be used in the detectors by decreasing thermal deformation and aberration. Mechanical stress, damage, poor surface quality or contamination can result in increased loss and thermal noise. Therefore, the characterization of mechanical loss in silicon test masses is necessary. In this project, we developed a technique to measure high Q-factor mechanical modes. We used finite element modeling to optimize the design of the test mass support structure to minimize the loss coupling from the support structure over a wide frequency range. Mechanical Q-factors of the order of 107 were achieved for several modes of a 10 cm diam. × 3 cm cylindrical silicon test mass with such a support at room temperature.
Novel fabrication tools for dynamic compression targets with engineered voids using photolithography methods
Authors: Pandolfi Silvia , Carver Thomas , Hodge Daniel , Leong Andrew F. T. , Kurzer-Ogul Kelin , Hart Philip , Galtier Eric , Khaghani Dimitri , Cunningham Eric , Nagler Bob , Lee Hae Ja , Bolme Cindy , Ramos Kyle , Li Kenan , Liu Yanwei , Sakdinawat Anne , Marchesini Stefano , Kozlowski Pawel M. , Curry Chandra B. , Decker Franz-Joseph , Vetter Sharon , Shang Jessica , Aluie Hussein , Dayton Matthew , Montgomery David S. , Sandberg Richard L. , Gleason Arianna E.
Published: October 2022

Mesoscale imperfections, such as pores and voids, can strongly modify the properties and the mechanical response of materials under extreme conditions. Tracking the material response and microstructure evolution during void collapse is crucial for understanding its performance. In particular, imperfections in the ablator materials, such as voids, can limit the efficiency of the fusion reaction and ultimately hinder ignition. To characterize how voids influence the response of materials during dynamic loading and seed hydrodynamic instabilities, we have developed a tailored fabrication procedure for designer targets with voids at specific locations. Our procedure uses SU-8 as a proxy for the ablator materials and hollow silica microspheres as a proxy for voids and pores. By using photolithography to design the targets’ geometry, we demonstrate precise and highly reproducible placement of a single void within the sample, which is key for a detailed understanding of its behavior under shock compression. This fabrication technique will benefit high-repetition rate experiments at x-ray and laser facilities. Insight from shock compression experiments will provide benchmarks for the next generation of microphysics modeling.
Performance and flow characteristics of the optimum rotors of Betz, Joukowsky, and Glauert at low tip-speed ratio
Authors: Bourhis M. , Pereira M. , Ravelet F.
Published: October 2022

The advent of the Internet of Things technology has led to a renewed interest in the use of low tip-speed ratio micro-scale wind turbines to supply power to battery-less microsystems. At low tip-speed ratio (λ), the blade geometry varies significantly depending on the optimal flow conditions used in the classical design method and the blade element/momentum theory (BEMT), and very few papers have examined this controversy. This experimental study aims to investigate the airflow and power characteristics of three 200-cm wind turbines designed according to the BEMT with three different optimum flow conditions at λ = 1: the Betz model, the Glauert model, and the Joukowsky model. Glauert optimum rotor achieves higher maximum power coefficient (Cp,max=0.34) than the optimum rotors of Betz (Cp,max=0.31) and Joukowsky (Cp,max=0.26). The two latter turbines have lower cut-in wind speed and their torque coefficient decreases linearly with the tip-speed ratio. Betz optimum rotor has a highly stable and persistent wake, whereas large recirculation bubbles and vortex breakdown are observed downstream the runners of Glauert and Joukowsky. The airflow velocity fields and induction factor distributions computed from stereoscopic particle image velocimetry acquisitions show significant differences between each rotor and also between the theoretical developments and the experimental results, especially for the Joukowsky rotor. In addition, even though the optimum flow conditions of Glauert or Betz appear to be the most appropriate models, a method based on flow deflection rather than on airfoil polar plots may be more pertinent for the design of low tip-speed ratio micro-scale wind turbines.
III-N polarization-graded transistors for millimeter-wave applications—Understanding and future potential
Authors: Fay Patrick , Moon Jeong-Sun , Rajan Siddharth
Published: October 2022

Advanced concepts in polarization engineering of III-N transistor structures are promising for enabling significant improvements in device performance for microwave through millimeter-wave applications. By going beyond the conventional abrupt-interface design concept that has dominated transistor design for decades, dramatic improvements in device linearity, maximum operating voltage, and power-added efficiency through the microwave and mm-wave regimes have been predicted in simulation and experimentally demonstrated. These improvements are enabled by improved physical understanding of electron transport and electrostatics, which can be exploited to enhance carrier velocity and enable intrinsic electric-field management.
Coupling between conduction and near-field radiative heat transfer in tip–plane geometry
Authors: Gharib Ali Barura Chams , Ben-Abdallah Philippe , Messina Riccardo
Published: October 2022

We analyze the coupling between conduction and radiative heat transfer in the near-field regime between two coaxial cylinders separated by a vacuum gap. By solving the heat transport equation in the steady-state regime between metals or polar materials, we highlight a flux saturation mechanism for the radiative transfer even without a non-local effect. In the case of polar materials, this saturation occurs in the separation distances in the range of 1–10 nm, which can be experimentally explored.
Micro-machined deep silicon atomic vapor cells
Authors: Dyer S. , Griffin P. F. , Arnold A. S. , Mirando F. , Burt D. P. , Riis E. , McGilligan J. P.
Published: October 2022

Using a simple and cost-effective water jet process, silicon etch depth limitations are overcome to realize a 6 mm deep atomic vapor cell. While the minimum silicon feature size was limited to a 1.5 mm width in these first generation vapor cells, we successfully demonstrate a two-chamber geometry by including a ∼25 mm meandering channel between the alkali pill chamber and the main interrogation chamber. We evaluate the impact of the channel conductance on the introduction of the alkali vapor density during the pill activation process and mitigate glass damage and pill contamination near the main chamber. Finally, we highlight the improved signal achievable in the 6 mm silicon cell compared to standard 2 mm path length silicon vapor cells.
Magnetic field driven dynamics in twisted bilayer artificial spin ice at superlattice angles
Authors: Begum Popy Rehana , Frank Julia , Stamps Robert L.
Published: October 2022

Geometrical designs of interacting nanomagnets have been studied extensively in the form of two-dimensional arrays called artificial spin ice. These systems are usually designed to create geometrical frustration and are of interest for the unusual and often surprising phenomena that can emerge. Advanced lithographic and element growth techniques have enabled the realization of complex designs that can involve elements arranged in three dimensions. Using numerical simulations employing the dumbbell approximation, we examine possible magnetic behaviors for bilayer artificial spin ice, in which the individual layers are rotated with respect to one another. The goal is to understand how magnetization dynamics are affected by long-range dipolar coupling that can be modified by varying the layer separation and layer alignment through rotation. We consider bilayers where the layers are both either square or pinwheel arrangements of islands. Magnetic reversal processes are studied and discussed in terms of domain and domain wall configurations of the magnetic islands. Unusual magnetic ordering is predicted for special angles that define lateral spin superlattices for the bilayer systems.
Implications of negative energy balance in lactating Barki and Rahmani ewes
Authors: Anwar M. M. , El-Mokadem M. Y. , Ramadan T. A. , Nour El-Din A. N. M. , Taha T. A. , Sharaby M. A. , Salem M. H. , Rashad A. M. A.
Published: October 2022

Context During lactation, ewes usually undergo a state of negative energy balance since the energy required for milk production and maintenance of body tissue functions exceeds energy ingested. Aims This study was performed to explore the impact of negative energy balance associated with lactation on milk yield and composition, metabolic profile and some reproductive traits in two different breeds of sheep. Methods In total, one hundred lactating Barki and Rahmani ewes (50 ewes per breed) were used for six consecutive parities to investigate the effects of breed, parity, week of lactation, and their interactions on milk yield and composition, including percentages of milk fat and milk protein, fat–protein ratio, energy-corrected milk, milk energy value, energy balance, some serum metabolites and reproductive traits. Milk and blood samples were collected weekly throughout the study. Key results Rahmani ewes had higher milk fat %, fat yield, protein %, protein yield and milk energy value, but lower fat–protein ratio than did Barki ewes. The greater value of energy balance and accumulated negative energy balance from parturition to energy balance equilibrium and fewer days from lambing to energy balance equilibrium were observed in Rahmani than in Barki ewes. Greater values of serum concentrations of total protein, albumin, cholesterol and lower values of aspartate aminotransferase and alanine aminotransferase were recorded in Rahmani than in Barki ewes. Reproductive traits, including days to the first oestrus and days to conception, recorded greater values in Barki than in Rahmani ewes. Conclusion Rahmani ewes possessed adaptive characteristics to the challenge of lactation, expressed as a lower value of fat–protein ratio, which indicated a tendency of energy balance stabilisation, than did Barki ewes. This tendency was reflected in improved reproductive traits by reducing days to first oestrus and days to conception in Rahmani compared with Barki ewes. Implications Lactation presents a critical stressful period in the dam productive life because of the high nutritional and other managerial requirements necessary for milk production. This study was conducted to assess and compare the sustainability of the two sheep breeds to the production expenditure during lactation.
A case for an active eukaryotic marine biosphere during the Proterozoic era
Authors: Eckford-Soper Lisa K. , Andersen Ken H. , Hansen Trine Frisbæk , Canfield Donald E.
Published: October 2022

The microfossil record demonstrates the presence of eukaryotic organisms in the marine ecosystem by about 1,700 million years ago (Ma). Despite this, steranes, a biomarker indicator of eukaryotic organisms, do not appear in the rock record until about 780 Ma in what is known as the “rise of algae.” Before this, it is argued that eukaryotes were minor ecosystem members, with prokaryotes dominating both primary production and ecosystem dynamics. In this view, the rise of algae was possibly sparked by increased nutrient availability supplying the higher nutrient requirements of eukaryotic algae. Here, we challenge this view. We use a size-based ecosystem model to show that the size distribution of preserved eukaryotic microfossils from 1,700 Ma and onward required an active eukaryote ecosystem complete with phototrophy, osmotrophy, phagotrophy, and mixotrophy. Model results suggest that eukaryotes accounted for one-half or more of the living biomass, with eukaryotic algae contributing to about one-half of total marine primary production. These ecosystems lived with deep-water phosphate levels of at least 10% of modern levels. The general lack of steranes in the pre–780-Ma rock record could be a result of poor preservation.
Dissecting the stability determinants of a challenging de novo protein fold using massively parallel design and experimentation
Authors: Kim Tae-Eun , Tsuboyama Kotaro , Houliston Scott , Martell Cydney M. , Phoumyvong Claire M. , Lemak Alexander , Haddox Hugh K. , Arrowsmith Cheryl H. , Rocklin Gabriel J.
Published: October 2022

Designing entirely new protein structures remains challenging because we do not fully understand the biophysical determinants of folding stability. Yet, some protein folds are easier to design than others. Previous work identified the 43-residue ɑββɑ fold as especially challenging: The best designs had only a 2% success rate, compared to 39 to 87% success for other simple folds [G. J. Rocklin et al., Science 357, 168–175 (2017)]. This suggested the ɑββɑ fold would be a useful model system for gaining a deeper understanding of folding stability determinants and for testing new protein design methods. Here, we designed over 10,000 new ɑββɑ proteins and found over 3,000 of them to fold into stable structures using a high-throughput protease-based assay. NMR, hydrogen-deuterium exchange, circular dichroism, deep mutational scanning, and scrambled sequence control experiments indicated that our stable designs fold into their designed ɑββɑ structures with exceptional stability for their small size. Our large dataset enabled us to quantify the influence of universal stability determinants including nonpolar burial, helix capping, and buried unsatisfied polar atoms, as well as stability determinants unique to the ɑββɑ topology. Our work demonstrates how large-scale design and test cycles can solve challenging design problems while illuminating the biophysical determinants of folding.
Feedback linking cell envelope stiffness, curvature, and synthesis enables robust rod-shaped bacterial growth
Authors: al-Mosleh Salem , Gopinathan Ajay , Santangelo Christian D. , Huang Kerwyn Casey , Rojas Enrique R.
Published: October 2022

Bacterial growth is remarkably robust to environmental fluctuations, yet the mechanisms of growth-rate homeostasis are poorly understood. Here, we combine theory and experiment to infer mechanisms by which
Escherichia coli
adapts its growth rate in response to changes in osmolarity, a fundamental physicochemical property of the environment. The central tenet of our theoretical model is that cell-envelope expansion is only sensitive to local information, such as enzyme concentrations, cell-envelope curvature, and mechanical strain in the envelope. We constrained this model with quantitative measurements of the dynamics of
E. coli
elongation rate and cell width after hyperosmotic shock. Our analysis demonstrated that adaptive cell-envelope softening is a key process underlying growth-rate homeostasis. Furthermore, our model correctly predicted that softening does not occur above a critical hyperosmotic shock magnitude and precisely recapitulated the elongation-rate dynamics in response to shocks with magnitude larger than this threshold. Finally, we found that, to coordinately achieve growth-rate and cell-width homeostasis, cells employ direct feedback between cell-envelope curvature and envelope expansion. In sum, our analysis points to cellular mechanisms of bacterial growth-rate homeostasis and provides a practical theoretical framework for understanding this process.
Real-space determination of the isolated magnetic skyrmion deformation under electric current flow
Authors: Yasin Fehmi Sami , Masell Jan , Karube Kosuke , Kikkawa Akiko , Taguchi Yasujiro , Tokura Yoshinori , Yu Xiuzhen
Published: October 2022

The manipulation and control of electron spins, the fundamental building blocks of magnetic domains and spin textures, are at the core of spintronics. Of particular interest is the effect of the electric current on topological magnetic skyrmions, such as the current-induced deformation of isolated skyrmions. The deformation has consequences ranging from perturbed dynamics to modified packing configurations. In this study, we measured the current-driven real-space deformation of isolated, pinned skyrmions within Co
10
Zn
10
at room temperature. We observed that the skyrmions are surprisingly soft, readily deforming during electric current application into an elliptical shape with a well-defined deformation axis (semimajor axis). We found that this axis rotates unidirectionally toward the current direction irrespective of electric current polarity and that the elliptical deformation reverses back upon current termination. We quantified the average distortion δ, which increased by ∼90% during the largest applied current density |
j
| = 8.46 ×10
9
A/m
2
when compared with the skyrmion’s intrinsic shape (

j
=
0

). Additionally, we demonstrated an approximately 120% average skyrmion core size expansion during current application, highlighting the skyrmions’ inherent topological protection. This evaluation of in situ electric current–induced skyrmion deformation paints a clearer picture of spin-polarized electron–skyrmion interactions and may prove essential in designing spintronic devices.
Human cerebellum and corticocerebellar connections involved in emotional memory enhancement
Authors: Fastenrath Matthias , Spalek Klara , Coynel David , Loos Eva , Milnik Annette , Egli Tobias , Schicktanz Nathalie , Geissmann Léonie , Roozendaal Benno , Papassotiropoulos Andreas , de Quervain Dominique J.-F.
Published: October 2022

Emotional information is better remembered than neutral information. Extensive evidence indicates that the amygdala and its interactions with other cerebral regions play an important role in the memory-enhancing effect of emotional arousal. While the cerebellum has been found to be involved in fear conditioning, its role in emotional enhancement of episodic memory is less clear. To address this issue, we used a whole-brain functional MRI approach in 1,418 healthy participants. First, we identified clusters significantly activated during enhanced memory encoding of negative and positive emotional pictures. In addition to the well-known emotional memory–related cerebral regions, we identified a cluster in the cerebellum. We then used dynamic causal modeling and identified several cerebellar connections with increased connection strength corresponding to enhanced emotional memory, including one to a cluster covering the amygdala and hippocampus, and bidirectional connections with a cluster covering the anterior cingulate cortex. The present findings indicate that the cerebellum is an integral part of a network involved in emotional enhancement of episodic memory.
Curriculum learning for human compositional generalization
Authors: Dekker Ronald B. , Otto Fabian , Summerfield Christopher
Published: October 2022

Generalization (or transfer) is the ability to repurpose knowledge in novel settings. It is often asserted that generalization is an important ingredient of human intelligence, but its extent, nature, and determinants have proved controversial. Here, we examine this ability with a paradigm that formalizes the transfer learning problem as one of recomposing existing functions to solve unseen problems. We find that people can generalize compositionally in ways that are elusive for standard neural networks and that human generalization benefits from training regimes in which items are axis aligned and temporally correlated. We describe a neural network model based around a Hebbian gating process that can capture how human generalization benefits from different training curricula. We additionally find that adult humans tend to learn composable functions asynchronously, exhibiting discontinuities in learning that resemble those seen in child development.
In vivo extracellular recordings of thalamic and cortical visual responses reveal V1 connectivity rules
Authors: Kraynyukova Nataliya , Renner Simon , Born Gregory , Bauer Yannik , Spacek Martin A. , Tushev Georgi , Busse Laura , Tchumatchenko Tatjana
Published: October 2022

The brain’s connectome provides the scaffold for canonical neural computations. However, a comparison of connectivity studies in the mouse primary visual cortex (V1) reveals that the average number and strength of connections between specific neuron types can vary. Can variability in V1 connectivity measurements coexist with canonical neural computations? We developed a theory-driven approach to deduce V1 network connectivity from visual responses in mouse V1 and visual thalamus (dLGN). Our method revealed that the same recorded visual responses were captured by multiple connectivity configurations. Remarkably, the magnitude and selectivity of connectivity weights followed a specific order across most of the inferred connectivity configurations. We argue that this order stems from the specific shapes of the recorded contrast response functions and contrast invariance of orientation tuning. Remarkably, despite variability across connectivity studies, connectivity weights computed from individual published connectivity reports followed the order we identified with our method, suggesting that the relations between the weights, rather than their magnitudes, represent a connectivity motif supporting canonical V1 computations.
Mesoscale structure–function relationships in mitochondrial transcriptional condensates
Authors: Feric Marina , Sarfallah Azadeh , Dar Furqan , Temiakov Dmitry , Pappu Rohit V. , Misteli Tom
Published: October 2022

In live cells, phase separation is thought to organize macromolecules into membraneless structures known as biomolecular condensates. Here, we reconstituted transcription in condensates from purified mitochondrial components using optimized in vitro reaction conditions to probe the structure–function relationships of biomolecular condensates. We find that the core components of the mt-transcription machinery form multiphasic, viscoelastic condensates in vitro. Strikingly, the rates of condensate-mediated transcription are substantially lower than in solution. The condensate-mediated decrease in transcriptional rates is associated with the formation of vesicle-like structures that are driven by the production and accumulation of RNA during transcription. The generation of RNA alters the global phase behavior and organization of transcription components within condensates. Coarse-grained simulations of mesoscale structures at equilibrium show that the components stably assemble into multiphasic condensates and that the vesicles formed in vitro are the result of dynamical arrest. Overall, our findings illustrate the complex phase behavior of transcribing, multicomponent condensates, and they highlight the intimate, bidirectional interplay of structure and function in transcriptional condensates.
ACBP/DBI protein neutralization confers autophagy-dependent organ protection through inhibition of cell loss, inflammation, and fibrosis
Authors: Motiño Omar , Lambertucci Flavia , Anagnostopoulos Gerasimos , Li Sijing , Nah Jihoon , Castoldi Francesca , Senovilla Laura , Montégut Léa , Chen Hui , Durand Sylvère , Bourgin Mélanie , Aprahamian Fanny , Nirmalathasan Nitharsshini , Alvarez-Valadez Karla , Sauvat Allan , Carbonnier Vincent , Djavaheri-Mergny Mojgan , Pietrocola Federico , Sadoshima Junichi , Maiuri Maria Chiara , Martins Isabelle , Kroemer Guido
Published: October 2022

Acyl-coenzyme A (CoA)–binding protein (ACBP), also known as diazepam-binding inhibitor (DBI), is an extracellular feedback regulator of autophagy. Here, we report that injection of a monoclonal antibody neutralizing ACBP/DBI (α-DBI) protects the murine liver against ischemia/reperfusion damage, intoxication by acetaminophen and concanavalin A, and nonalcoholic steatohepatitis caused by methionine/choline-deficient diet as well as against liver fibrosis induced by bile duct ligation or carbon tetrachloride. α-DBI downregulated proinflammatory and profibrotic genes and upregulated antioxidant defenses and fatty acid oxidation in the liver. The hepatoprotective effects of α-DBI were mimicked by the induction of ACBP/DBI-specific autoantibodies, an inducible
Acbp/Dbi
knockout or a constitutive

Gabrg2
F77I

mutation that abolishes ACBP/DBI binding to the GABA
A
receptor. Liver-protective α-DBI effects were lost when autophagy was pharmacologically blocked or genetically inhibited by knockout of
Atg4b
. Of note, α-DBI also reduced myocardium infarction and lung fibrosis, supporting the contention that it mediates broad organ-protective effects against multiple insults.
SPACA9 is a lumenal protein of human ciliary singlet and doublet microtubules
Authors: Gui Miao , Croft Jacob T. , Zabeo Davide , Acharya Vajradhar , Kollman Justin M. , Burgoyne Thomas , Höög Johanna L. , Brown Alan
Published: October 2022

The cilium-centrosome complex contains triplet, doublet, and singlet microtubules. The lumenal surfaces of each microtubule within this diverse array are decorated by microtubule inner proteins (MIPs). Here, we used single-particle cryo-electron microscopy methods to build atomic models of two types of human ciliary microtubule: the doublet microtubules of multiciliated respiratory cells and the distal singlet microtubules of monoflagellated human spermatozoa. We discover that SPACA9 is a polyspecific MIP capable of binding both microtubule types. SPACA9 forms intralumenal striations in the B tubule of respiratory doublet microtubules and noncontinuous spirals in sperm singlet microtubules. By acquiring new and reanalyzing previous cryo-electron tomography data, we show that SPACA9-like intralumenal striations are common features of different microtubule types in animal cilia. Our structures provide detailed references to help rationalize ciliopathy-causing mutations and position cryo-EM as a tool for the analysis of samples obtained directly from ciliopathy patients.
DNA polymerase epsilon interacts with SUVH2/9 to repress the expression of genes associated with meiotic DSB hotspot in
Arabidopsis
Authors: Wang Cong , Huang Jiyue , Zhang Jun , Yu Yue , Copenhaver Gregory P. , You Chenjiang , Wang Yingxiang
Published: October 2022

Meiotic recombination is initiated by the SPORULATION 11 (SPO11)–triggered formation of double-strand breaks (DSBs) that usually occur in open chromatin with active transcriptional features in many eukaryotes. However, gene transcription at DSB sites appears to be detrimental for repair, but the regulatory mechanisms governing transcription at meiotic DSB sites are largely undefined in plants. Here, we demonstrate that the largest DNA polymerase epsilon subunit POL2A interacts with SU(VAR)3 to 9 homologs SUVH2 and SUVH9. N-SIM (structured illumination microscopy) observation shows that the colocalization of SUVH2 with the meiotic DSB marker γ-H2AX is dependent on POL2A. RNA-seq of male meiocytes demonstrates that POL2A and SUVH2 jointly repress the expression of 865 genes, which have several known characteristics associated with meiotic DSB sites. Bisulfite-seq and small RNA-seq of male meiocytes support the idea that the silencing of these genes by POL2A and SUVH2/9 is likely independent of CHH methylation or 24-nt siRNA accumulation. Moreover,
pol2a suvh2 suvh9
triple mutants have more severe defects in meiotic recombination and fertility compared with either
pol2a
or
suvh2 suvh9
. Our results not only identify a epigenetic regulatory mechanism for gene silencing in male meiocytes but also reveal roles for DNA polymerase and SUVH2/9 beyond their classic functions in mitosis.
Novel and multifaceted regulations of photoperiodic flowering by phytochrome A in soybean
Authors: Lin Xiaoya , Dong Lidong , Tang Yang , Li Haiyang , Cheng Qun , Li Hong , Zhang Ting , Ma Lixin , Xiang Hongli , Chen Linnan , Nan Haiyang , Fang Chao , Lu Sijia , Li Jigang , Liu Baohui , Kong Fanjiang
Published: October 2022

Photoperiod is an important environmental cue. Plants can distinguish the seasons and flower at the right time through sensing the photoperiod. Soybean is a sensitive short-day crop, and the timing of flowering varies greatly at different latitudes, thus affecting yields. Soybean cultivars in high latitudes adapt to the long day by the impairment of two phytochrome genes,
PHYA3
and
PHYA2
, and the legume-specific flowering suppressor,
E1
. However, the regulating mechanism underlying phyA and E1 in soybean remains largely unknown. Here, we classified the regulation of the E1 family by phyA2 and phyA3 at the transcriptional and posttranscriptional levels, revealing that phyA2 and phyA3 regulate E1 by directly binding to LUX proteins, the critical component of the evening complex, to regulate the stability of LUX proteins. In addition, phyA2 and phyA3 can also directly associate with E1 and its homologs to stabilize the E1 proteins. Therefore, phyA homologs control the core flowering suppressor E1 at both the transcriptional and posttranscriptional levels, to double ensure the E1 activity. Thus, our results disclose a photoperiod flowering mechanism in plants by which the phytochrome A regulates LUX and E1 activity.
The scientific value of numerical measures of human feelings
Authors: Kaiser Caspar , Oswald Andrew J.
Published: October 2022

Human feelings measured in integers (
my happiness is an 8 out of 10
,
my pain 2 out of 6
) have no objective scientific basis. They are “made-up” numbers on a scale that does not exist. Yet such data are extensively collected—despite criticism from, especially, economists—by governments and international organizations. We examine this paradox. We draw upon longitudinal information on the feelings and decisions of tens of thousands of randomly sampled citizens followed through time over four decades in three countries (
n
= 700,000 approximately). First, we show that a single feelings integer has greater predictive power than does a combined set of economic and social variables. Second, there is a clear inverse relationship between feelings integers and subsequent get-me-out-of-here actions (in the domain of neighborhoods, partners, jobs, and hospital visits). Third, this feelings-to-actions relationship takes a generic form, is consistently replicable, and is fairly close to linear in structure. Therefore, it seems that human beings can successfully operationalize an integer scale for feelings even though there is no true scale. How individuals are able to achieve this is not currently known. The implied scientific puzzle—an inherently cross-disciplinary one—demands attention.
Combating Li metal deposits in all-solid-state battery via the piezoelectric and ferroelectric effects
Authors: Tao Jianming , Chen Yue , Bhardwaj Aman , Wen Lang , Li Jiaxin , Kolosov Oleg V. , Lin Yingbin , Hong Zhensheng , Huang Zhigao , Mathur Sanjay
Published: October 2022

All-solid-state Li-metal batteries (ASSLBs) are highly desirable, due to their inherent safety and high energy density; however, the irregular and uncontrolled growth of Li filaments is detrimental to interfacial stability and safety. Herein, we report on the incorporation of piezo-/ferroelectric BaTiO
3
(BTO) nanofibers into solid electrolytes and determination of electric-field distribution due to BTO inclusion that effectively regulates the nucleation and growth of Li dendrites. Theoretical simulations predict that the piezoelectric effect of BTO embedded in solid electrolyte reduces the driving force of dendrite growth at high curvatures, while its ferroelectricity reduces the overpotential, which helps to regularize Li deposition and Li
+
flux. Polarization reversal of soft solid electrolytes was identified, confirming a regular deposition and morphology alteration of Li. As expected, the ASSLBs operating with LiFePO
4
/Li and poly(ethylene oxide) (PEO)/garnet solid electrolyte containing 10% BTO additive showed a steady and long cycle life with a reversible capacity of 103.2 mAh g
−1
over 500 cycles at 1 C. Furthermore, the comparable cyclability and flexibility of the scalable pouch cells prepared and the successful validation in the sulfide electrolytes, demonstrating its universal and promising application for the integration of Li metal anodes in solid-state batteries.
Aqueous microdroplets enable abiotic synthesis and chain extension of unique peptide isomers from free amino acids
Authors: Holden Dylan T. , Morato Nicolás M. , Cooks R. Graham
Published: October 2022

Amide bond formation, the essential condensation reaction underlying peptide synthesis, is hindered in aqueous systems by the thermodynamic constraints associated with dehydration. This represents a key difficulty for the widely held view that prebiotic chemical evolution leading to the formation of the first biomolecules occurred in an oceanic environment. Recent evidence for the acceleration of chemical reactions at droplet interfaces led us to explore aqueous amino acid droplet chemistry. We report the formation of dipeptide isomer ions from free glycine or L-alanine at the air–water interface of aqueous microdroplets emanating from a single spray source (with or without applied potential) during their flight toward the inlet of a mass spectrometer. The proposed isomeric dipeptide ion is an oxazolidinone that takes fully covalent and ion-neutral complex forms. This structure is consistent with observed fragmentation patterns and its conversion to authentic dipeptide ions upon gentle collisions and for its formation from authentic dipeptides at ultra-low concentrations. It also rationalizes the results of droplet fusion experiments that show that the dipeptide isomer facilitates additional amide bond formation events, yielding authentic tri- through hexapeptides. We propose that the interface of aqueous microdroplets serves as a drying surface that shifts the equilibrium between free amino acids in favor of dehydration via stabilization of the dipeptide isomers. These findings offer a possible solution to the water paradox of biopolymer synthesis in prebiotic chemistry.
Chemistry-informed molecular graph as reaction descriptor for machine-learned retrosynthesis planning
Authors: Zhang Baicheng , Zhang Xiaolong , Du Wenjie , Song Zhaokun , Zhang Guozhen , Zhang Guoqing , Wang Yang , Chen Xin , Jiang Jun , Luo Yi
Published: October 2022

Infusing “chemical wisdom” should improve the data-driven approaches that rely exclusively on historical synthetic data for automatic retrosynthesis planning. For this purpose, we designed a chemistry-informed molecular graph (CIMG) to describe chemical reactions. A collection of key information that is most relevant to chemical reactions is integrated in CIMG:NMR chemical shifts as vertex features, bond dissociation energies as edge features, and solvent/catalyst information as global features. For any given compound as a target, a product CIMG is generated and exploited by a graph neural network (GNN) model to choose reaction template(s) leading to this product. A reactant CIMG is then inferred and used in two GNN models to select appropriate catalyst and solvent, respectively. Finally, a fourth GNN model compares the two CIMG descriptors to check the plausibility of the proposed reaction. A reaction vector is obtained for every molecule in training these models. The chemical wisdom of reaction propensity contained in the pretrained reaction vectors is exploited to autocategorize molecules/reactions and to accelerate Monte Carlo tree search (MCTS) for multistep retrosynthesis planning. Full synthetic routes with recommended catalysts/solvents are predicted efficiently using this CIMG-based approach.
Cooperation loci are more pleiotropic than private loci in the bacterium
Pseudomonas aeruginosa
Authors: Scott Trey J.
Published: October 2022

Pleiotropy may affect the maintenance of cooperation by limiting cheater mutants if such mutants lose other important traits. If pleiotropy limits cheaters, selection may favor cooperation loci that are more pleiotropic. However, the same should not be true for private loci with functions unrelated to cooperation. Pleiotropy in cooperative loci has mostly been studied with single loci and has not been measured on a wide scale or compared to a suitable set of control loci with private functions. I remedy this gap by comparing genomic measures of pleiotropy in previously identified cooperative and private loci in
Pseudomonas aeruginosa
. I found that cooperative loci in
P. aeruginosa
tended to be more pleiotropic than private loci according to the number of protein–protein interactions, the number of gene ontology terms, and gene expression specificity. These results show that pleiotropy may be a general way to limit cheating and that cooperation may shape pleiotropy in the genome.
‘I partied my way to [my] Hungary’: The agency-driven engagements of Hungarian-Australians to shape feelings of place and belonging outside their diaspora tourism programme
Authors: Kantek Julia , Onnudottir Helena , Veljanova Irena
Published: October 2022

The Balassi Institute is Hungary’s cultural diplomacy organisation. The Institute’s 10-month ‘Balassi program’ invites Hungarians from the diaspora to participate in a culturally immersive and educational experience in Hungary. This paper draws on interviews with 17 Hungarian-Australians who attended the programme between 2001 and 2018. Bourdieu’s Habitus, capital and ‘field of possibles’ are used to analyse their experiences of belonging during their time in Hungary, particularly everyday engagements where they partied, danced, and formed friendships in nightclubs, folk bars, and community groups. The paper highlights that while the Balassi programme’s curriculum aims to habituate national consciousness, the defining elements of belonging were agency-driven. By manoeuvring their capital and prioritising everyday social engagements, participants constructed ‘relationships with the nation’, while maintaining a minimum commitment to the programme. Thus, when exploring the aims of State-led diaspora tourism programmes, participant choices outside these programmes must be considered a prominent force in shaping belonging.
Enemies and friends. The instrumental social construction of populist identity through twitter in Italy at the time of COVID-19
Authors: Loner Enzo
Published: October 2022

Based on 2020 Twitter data, this article studies the social construction of populist identity in Italy. Starting from Tajfel's social identity theory (1978), the research aims at dissecting the elements at the basis of the populist identity construction process. The analysis focuses on both quantitative analysis and qualitative inspection of the tweets of four populist leaders, namely Salvini (LN), Meloni (FDI), Berlusconi (FI), and Di Maio (M5S). Results highlight the outgroup's position and its functional role in strengthening relative deprivation to facilitate ingroup identification. In addition, the populist social identity is built on group membership and the biased comparison between the ingroup and one or more outgroups. Results demonstrate how leaders’ strategies change based on being in government or not and according to their position on the left-right axis. In this context, the pandemic offered a further political opportunity, especially to those who have found themselves in government.
Dynamics of a nonminimally coupled scalar field in asymptotically AdS
4 spacetime
Authors: Pandya Alex , Ripley Justin L
Published: October 2022

We numerically investigate the stability of four-dimensional asymptotically anti-de Sitter (AdS
4) spacetime for a class of nonminimally coupled scalar field theories. In particular, we study how the coupling affects the formation of black holes, and the transfer of energy to different spatial/temporal scales. We conclude by detailing the well-known analogy between the nonminimally coupled scalar-field stress-energy tensor and that of a viscous relativistic fluid, and discuss the limitations of that analogy when it is applied to anisotropic scalar field configurations in asymptotically AdS spacetimes.