bluuebunny/crossref_metadata_2025 huggingface dataset:
Incorporating social payoff into reinforcement learning promotes cooperation
Authors: Fan Litong , Song Zhao , Wang Lu , Liu Yang , Wang Zhen
Published: December 2022

Reinforcement learning has been demonstrated to be an effective approach to investigate the dynamic of strategy updating and the learning process of agents in game theory. Most studies have shown that Q-learning failed to resolve the problem of cooperation in well-mixed populations or homogeneous networks. To this aim, we investigate the self-regarding Q-learning’s effect on cooperation in spatial prisoner’s dilemma games by incorporating the social payoff. Here, we redefine the reward term of self-regarding Q-learning by involving the social payoff; that is, the reward is defined as a monotonic function of the individual payoff and the social payoff represented by its neighbors’ payoff. Numerical simulations reveal that such a framework can facilitate cooperation remarkably because the social payoff ensures agents learn to cooperate toward socially optimal outcomes. Moreover, we find that self-regarding Q-learning is an innovative rule that ensures cooperators coexist with defectors even at high temptations to defection. The investigation of the emergence and stability of the sublattice-ordered structure shows that such a mechanism tends to generate a checkerboard pattern to increase agents’ payoff. Finally, the effects of Q-learning parameters are also analyzed, and the robustness of this mechanism is verified on different networks.
Stationary solutions to a compressible non-Newtonian fluid with general boundary conditions
Authors: Fang Li , Zhao Yugang , Guo Zhenhua
Published: December 2022

This paper is concerned with the steady-state equations describing a motion of some non-Newtonian fluids whose viscosity has a power-structure with an exponent r. The existence of weak solutions is established through a two-level approximation procedure and weak convergence argument whenever r > 2, which is the optimal bound for the existence of weak solutions.
Bandgap prediction for a beam containing membrane-arch-mass resonators
Authors: Kao De-Wei , Chen Jung-San , Chen Yu-Bin
Published: December 2022

This work aims to propose a promising locally resonating system consisting of a tensioned elastic membrane and two-arch masses attached on the membrane surface. Traditional membrane-type resonators, which usually create one obvious attenuation zone at low frequencies, might not be efficient in multi-frequency vibration suppression. The proposed structure can produce an extra clear flexural attenuation region and shift bandgap frequencies below 300 Hz. By adjusting geometric parameters (thickness, width, and location) of the arch mass, the bandgap region can be tuned. Introducing a feasible analytical model for accurately predicting the first and second initial frequencies of the bandgaps for a beam structure containing membrane-arch-mass resonators is another focus of this study. The proposed theoretical framework can be used to tune the bandgap to different target frequency ranges without knowing the actual width of the bandgap. Finite-element analysis and experiments are conducted to verify the theoretical predictions. A good agreement is seen among the theoretical, finite-element analysis, and experimental results. In addition, adjacent cells with different arch-mass distributions can generate two pairs of flexural bandgaps, increasing the practicality in engineering applications. The proposed structure might be used in low-frequency vibration isolation and filters.
Film thickness dependence of in-plane ferroelastic domain structure in constrained tetragonal PbTiO3 films induced by isotropic tensile strain
Authors: Ehara Yoshitaka , Nakashima Takaaki , Ichinose Daichi , Shimizu Takao , Shiraishi Takahisa , Sakata Osami , Yamada Tomoaki , Yasui Shintaro , Nishida Ken , Funakubo Hiroshi
Published: December 2022

In this study, the ferroelectric phase of PbTiO3 (PTO) thin films was grown on cubic single-crystal KTaO3 (KTO) substrates using metal–organic chemical vapor deposition. X-ray diffraction (XRD) was used to reveal an a1/a2 domain structure, which remained unchanged down to a film thickness of 2 nm. The a1 and a2 polydomains do not have a simple tetragonal symmetry because aa∥ and aa⊥ do not have the same values. The crystallographic tilt angle, α, is defined based on the rotation angle of the PTO lattice with respect to the cubic phase of KTO substrates. The in-plane tetragonal distortion (ca∥/aa∥) and α decreased with the decrease in the film thickness, following the in-plane tetragonal geometric equation: α=tan−1(ca∥aa∥)−45°. The isotropic tensile strains induced in-plane polarization directions along the [100] and [010] axes of the substrates. These axes are formed via the a1/a2 polydomain of the tetragonal-like phase. Moreover, synchrotron in-plane grazing incidence XRD and piezoelectric force microscopy were used to reveal the thickness dependency of the periodic domain width of the ferroelastic a1/a2 domain. The periodic domain width in the PTO films decreased, following Kittel's law, with the reduction in the film thickness.
Inverse relationship between diffusion coefficient and mass for a free particle system: Approach by using maximum caliber principle and Monte Carlo simulations
Authors: González Díaz D.
Published: December 2022

A derivation of the diffusion equation is presented using the maximum caliber principle and the continuity equation for a system composed of paths traveled by a free particle in a time interval. By identifying the diffusion coefficient in the obtained diffusion equation, it is shown that there is an inverse proportionality relationship concerning the particle’s mass so that a higher mass is related to lower diffusion, and the lower mass is connected to the higher diffusion. This relationship is also shown using Monte Carlo simulations to sample the path space for a free particle system and then using the time slicing equation to obtain the probability of the particle position for each time showing the diffusion behavior for different masses.
High conductivity β-Ga2O3 formed by hot Si ion implantation
Authors: Sardar Arka , Isaacs-Smith Tamara , Lawson Jacob , Asel Thaddeus , Comes Ryan B. , Merrett Joseph N. , Dhar Sarit
Published: December 2022

This work demonstrates the advantage of carrying out silicon ion (Si+) implantation at high temperatures for forming controlled heavily doped regions in gallium oxide. Room temperature (RT, 25 °C) and high temperature (HT, 600 °C) Si implants were carried out into MBE grown (010) β-Ga2O3 films to form ∼350 nm deep Si-doped layers with average concentrations up to ∼1.2 × 1020 cm−3. For such high concentrations, the RT sample was too resistive for measurement, but the HT samples had 82.1% Si dopant activation efficiency with a high sheet electron concentration of 3.3 × 1015 cm−2 and an excellent mobility of 92.8 cm2/V·s at room temperature. X-ray diffraction measurements indicate that HT implantation prevents the formation of other Ga2O3 phases and results in reduced structural defects and lattice damage. These results are highly encouraging for achieving ultra-low resistance heavily doped Ga2O3 layers using ion implantation.
Optoelectronic synaptic device based on ZnO/HfOx heterojunction for high-performance neuromorphic vision system
Authors: Shan Xuanyu , Zhao Chenyi , Lin Ya , Liu Jilin , Zhang Xiaohan , Tao Ye , Wang Chunliang , Zhao Xiaoning , Wang Zhongqiang , Xu Haiyang , Liu Yichun
Published: December 2022

Optoelectronic synapses are considered to be important cornerstones in the construction of neuromorphic computing systems because of their low power consumption, high operating speeds, and high scalability. In this work, we demonstrate an optoelectronic synaptic device based on a ZnO/HfOx heterojunction in which optical potentiation/electrical depression behaviors and nonvolatile high current state can be implemented. The heterojunction device exhibits conductance evolution with high linearity. The excellent optoelectronic memristive behavior of the device can be attributed to the interface barrier between ZnO and HfOx, which hinders the recombination of photo-excited electron–hole pairs to increase the carrier lifetime, and realizes the nonvolatile high current state. More importantly, the artificial vision system based on optoelectronic synaptic devices can achieved a high recognition accuracy of 96.1%. Our work provides a feasible pathway toward the development of optoelectronic synaptic devices for use in high-performance neuromorphic vision systems.
Electrocaloric cooling—From materials to devices
Authors: Chen Xin , Shvartsman Vladimir V. , Lupascu Doru C. , Zhang Q. M.
Published: December 2022

More than a decade of active electrocaloric (EC) material research has produced several EC materials that exhibit a giant electrocaloric effect (ECE) at high electric fields, which is assured by direct measurement. These EC materials have enabled the demonstration of EC cooling devices, which exhibit temperature lifts of more than 10 K. These research and development efforts have revealed the critical importance of electrical breakdown, which is common in all electric and dielectric materials and devices under high voltages and electric fields. In general, the electric field for reliable device operation of dielectrics has to be less than 25% of the typical electric breakdown strength. To realize EC cooling devices with competitive performance requires advanced EC materials that generate large ECE (ΔT > 5 K) under these low electric fields. Double-bond (DB) defect modified P(VDF-TrFE-CFE) relaxor polymers, as reported recently, generate large ECE under low electric fields without any fatigue effects even after 1 × 106 field cycles. These relaxor ferroelectrics promise to meet the application challenge. A closely coupled experimental and theoretical study of EC materials will undoubtedly lead to advanced EC materials that generate large ECE at low electric fields beyond the DB modified relaxor polymers. This will result in practical and high-performance EC coolers, which are environmentally benign, compressor-free, and highly efficient.
The worldwide networks of spread of recorded alien species
Authors: Capinha César , Essl Franz , Porto Miguel , Seebens Hanno
Published: December 2022

Our ability to predict the spread of alien species is largely based on knowledge of previous invasion dynamics of individual species. However, in view of the large and growing number of alien species, understanding universal spread patterns common among taxa but specific to regions would considerably improve our ability to predict future dynamics of biological invasions. Here, using a comprehensive dataset of years of first record of alien species for four major biological groups (birds, nonmarine fishes, insects, and vascular plants), we applied a network approach to uncover frequent sequential patterns of first recordings of alien species across countries worldwide. Our analysis identified a few countries as consistent early recorders of alien species, with many subsequent records reported from countries in close geographic vicinity. These findings indicate that the spread network of alien species consists of two levels, a backbone of main dispersal hubs, driving intercontinental species movement, and subsequent intracontinental radiative spread in their vicinity. Geographical proximity and climatic similarity were significant predictors of same-species recording among countries. International trade was a significant predictor of the relative timing of species recordings, with countries having higher levels of trade flows consistently recording the species earlier. Targeting the countries that have emerged as hubs for the early spread of alien species may have substantial cascading effects on the global spread network of alien species, significantly reducing biological invasions. Furthermore, using these countries as early-warning system of upcoming invasions may also boost national prevention and invasion preparedness efforts.
Rapid infant learning of syntactic–semantic links
Authors: Barbir Monica , Babineau Mireille J. , Fiévet Anne-Caroline , Christophe Anne
Published: December 2022

In the second year of life, infants begin to rapidly acquire the lexicon of their native language. A key learning mechanism underlying this acceleration is syntactic bootstrapping: the use of hidden cues in grammar to facilitate vocabulary learning. How infants forge the syntactic–semantic links that underlie this mechanism, however, remains speculative. A hurdle for theories is identifying computationally light strategies that have high precision within the complexity of the linguistic signal. Here, we presented 20-mo-old infants with novel grammatical elements in a complex natural language environment and measured their resultant vocabulary expansion. We found that infants can learn and exploit a natural language syntactic–semantic link in less than 30 min. The rapid speed of acquisition of a new syntactic bootstrap indicates that even emergent syntactic–semantic links can accelerate language learning. The results suggest that infants employ a cognitive network of efficient learning strategies to self-supervise language development.
In situ turning defects of exfoliated Ti
3
C
2
MXene into Fenton-like catalytic active sites
Authors: Jiang Yue , Baimanov Didar , Jin Shan , Cheuk-Fung Law Japhet , Zhao Pengcheng , Tang Juanjuan , Peng Jian , Wang Liming , Leung Kelvin Sze-Yin , Sheng Wenchao , Lin Sijie
Published: December 2022

Controllable in situ formation of nanoclusters with discrete active sites is highly desirable in heterogeneous catalysis. Herein, a titanium oxide–based Fenton-like catalyst is constructed using exfoliated Ti
3
C
2
MXene as a template. Theoretical calculations reveal that a redox reaction between the surface Ti-deficit vacancies of the exfoliated Ti
3
C
2
MXene and H
2
O
2
molecules facilitates the in situ conversion of surface defects into titanium oxide nanoclusters anchoring on amorphous carbon (TiO
x
@C). The presence of mixed-valence Ti
δ+
(δ = 0, 2, 3, and 4) within TiO
x
@C is confirmed by X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure (XAFS) characterizations. The abundant surface defects within TiO
x
@C effectively promote the generation of reactive oxygen species (ROS) leading to superior and stable Fenton-like catalytic degradation of atrazine, a typical agricultural herbicide. Such an in situ construction of Fenton-like catalysts through defect engineering also applies to other MXene family materials, such as V
2
C and Nb
2
C.
Incident dementia and long-term exposure to constituents of fine particle air pollution: A national cohort study in the United States
Authors: Shi Liuhua , Zhu Qiao , Wang Yifan , Hao Hua , Zhang Haisu , Schwartz Joel , Amini Heresh , van Donkelaar Aaron , Martin Randall V. , Steenland Kyle , Sarnat Jeremy A. , Caudle W. Michael , Ma Tszshan , Li Haomin , Chang Howard H. , Liu Jeremiah Z. , Wingo Thomas , Mao Xiaobo , Russell Armistead G. , Weber Rodney J. , Liu Pengfei
Published: December 2022

Growing evidence suggests that fine particulate matter (PM
2.5
) likely increases the risks of dementia, yet little is known about the relative contributions of different constituents. Here, we conducted a nationwide population-based cohort study (2000 to 2017) by integrating the Medicare Chronic Conditions Warehouse database and two independently sourced datasets of high-resolution PM
2.5
major chemical composition, including black carbon (BC), organic matter (OM), nitrate (NO
3
−
), sulfate (SO
4
2−
), ammonium (NH
4
+
), and soil dust (DUST). To investigate the impact of long-term exposure to PM
2.5
constituents on incident all-cause dementia and Alzheimer’s disease (AD), hazard ratios for dementia and AD were estimated using Cox proportional hazards models, and penalized splines were used to evaluate potential nonlinear concentration–response (C-R) relationships. Results using two exposure datasets consistently indicated higher rates of incident dementia and AD for an increased exposure to PM
2.5
and its major constituents. An interquartile range increase in PM
2.5
mass was associated with a 6 to 7% increase in dementia incidence and a 9% increase in AD incidence. For different PM
2.5
constituents, associations remained significant for BC, OM, SO
4
2−
, and NH
4
+
for both end points (even after adjustments of other constituents), among which BC and SO
4
2−
showed the strongest associations. All constituents had largely linear C-R relationships in the low exposure range, but most tailed off at higher exposure concentrations. Our findings suggest that long-term exposure to PM
2.5
is significantly associated with higher rates of incident dementia and AD and that SO
4
2−
, BC, and OM related to traffic and fossil fuel combustion might drive the observed associations.
Structure-based discovery of potent WD repeat domain 5 inhibitors that demonstrate efficacy and safety in preclinical animal models
Authors: Teuscher Kevin B. , Chowdhury Somenath , Meyers Kenneth M. , Tian Jianhua , Sai Jiqing , Van Meveren Mayme , South Taylor M. , Sensintaffar John L. , Rietz Tyson A. , Goswami Soumita , Wang Jing , Grieb Brian C. , Lorey Shelly L. , Howard Gregory C. , Liu Qi , Moore William J. , Stott Gordon M. , Tansey William P. , Lee Taekyu , Fesik Stephen W.
Published: December 2022

WD repeat domain 5 (WDR5) is a core scaffolding component of many multiprotein complexes that perform a variety of critical chromatin-centric processes in the nucleus. WDR5 is a component of the mixed lineage leukemia MLL/SET complex and localizes MYC to chromatin at tumor-critical target genes. As a part of these complexes, WDR5 plays a role in sustaining oncogenesis in a variety of human cancers that are often associated with poor prognoses. Thus, WDR5 has been recognized as an attractive therapeutic target for treating both solid and hematological tumors. Previously, small-molecule inhibitors of the WDR5-interaction (WIN) site and WDR5 degraders have demonstrated robust in vitro cellular efficacy in cancer cell lines and established the therapeutic potential of WDR5. However, these agents have not demonstrated significant in vivo efficacy at pharmacologically relevant doses by oral administration in animal disease models. We have discovered WDR5 WIN-site inhibitors that feature bicyclic heteroaryl P
7
units through structure-based design and address the limitations of our previous series of small-molecule inhibitors. Importantly, our lead compounds exhibit enhanced on-target potency, excellent oral pharmacokinetic (PK) profiles, and potent dose-dependent in vivo efficacy in a mouse MV4:11 subcutaneous xenograft model by oral dosing. Furthermore, these in vivo probes show excellent tolerability under a repeated high-dose regimen in rodents to demonstrate the safety of the WDR5 WIN-site inhibition mechanism. Collectively, our results provide strong support for WDR5 WIN-site inhibitors to be utilized as potential anticancer therapeutics.
Distinct ecological fitness factors coordinated by a conserved
Escherichia coli
regulator during systemic bloodstream infection
Authors: O’Boyle Nicky , Douce Gillian R. , Farrell Gillian , Rattray Nicholas J. W. , Schembri Mark A. , Roe Andrew J. , Connolly James P. R.
Published: December 2022

The ability of bacterial pathogens to adapt to host niches is driven by the carriage and regulation of genes that benefit pathogenic lifestyles. Genes that encode virulence or fitness-enhancing factors must be regulated in response to changing host environments to allow rapid response to challenges presented by the host. Furthermore, this process can be controlled by preexisting transcription factors (TFs) that acquire new roles in tailoring regulatory networks, specifically in pathogens. However, the mechanisms underlying this process are poorly understood. The highly conserved
Escherichia coli
TF YhaJ exhibits distinct genome-binding dynamics and transcriptome control in pathotypes that occupy different host niches, such as uropathogenic
E. coli
(UPEC). Here, we report that this important regulator is required for UPEC systemic survival during murine bloodstream infection (BSI). This advantage is gained through the coordinated regulation of a small regulon comprised of both virulence and metabolic genes. YhaJ coordinates activation of both Type 1 and F1C fimbriae, as well as biosynthesis of the amino acid tryptophan, by both direct and indirect mechanisms. Deletion of
yhaJ
or the individual genes under its control leads to attenuated survival during BSI. Furthermore, all three systems are up-regulated in response to signals derived from serum or systemic host tissue, but not urine, suggesting a niche-specific regulatory trigger that enhances UPEC fitness via pleiotropic mechanisms. Collectively, our results identify YhaJ as a pathotype-specific regulatory aide, enhancing the expression of key genes that are collectively required for UPEC bloodstream pathogenesis.
A synaptic filtering mechanism in visual threat identification in mouse
Authors: Wu Qiwen , Li E. , Zhang Yifeng
Published: December 2022

Predator detection is key to animal’s survival. Superior colliculus (SC) orchestrates the animal’s innate defensive responses to visually detected threats, but how threat information is transmitted from the retina to SC is unknown. We discovered that narrow-field neurons in SC were key in this pathway. Using in vivo calcium imaging and optogenetics-assisted interrogation of circuit and synaptic connections, we found that the visual responses of narrow-field neurons were correlated with the animal’s defensive behaviors toward visual stimuli. Activation of these neurons triggered defensive behaviors, and ablation of them impaired the animals’ defensive responses to looming stimuli. They receive monosynaptic inputs from looming-sensitive OFF-transient alpha retinal ganglion cells, and the synaptic transmission has a unique band-pass feature that helps to shape their stimulus selectivity. Our results describe a cell-type specific retinotectal connection for visual threat detection, and a coding mechanism based on synaptic filtering.
Computational design of CRISPR guide RNAs to enable strain-specific control of microbial consortia
Authors: Rottinghaus Austin G. , Vo Steven , Moon Tae Seok
Published: December 2022

Microbes naturally coexist in complex, multistrain communities. However, extracting individual microbes from and specifically manipulating the composition of these consortia remain challenging. The sequence-specific nature of CRISPR guide RNAs can be leveraged to accurately differentiate microorganisms and facilitate the creation of tools that can achieve these tasks. We developed a computational program, ssCRISPR, which designs strain-specific CRISPR guide RNA sequences with user-specified target strains, protected strains, and guide RNA properties. We experimentally verify the accuracy of the strain specificity predictions in both
Escherichia coli
and
Pseudomonas spp.
and show that up to three nucleotide mismatches are often required to ensure perfect specificity. To demonstrate the functionality of ssCRISPR, we apply computationally designed CRISPR-Cas9 guide RNAs to two applications: the purification of specific microbes through one- and two-plasmid transformation workflows and the targeted removal of specific microbes using DNA-loaded liposomes. For strain purification, we utilize gRNAs designed to target and kill all microbes in a consortium except the specific microbe to be isolated. For strain elimination, we utilize gRNAs designed to target only the unwanted microbe while protecting all other strains in the community. ssCRISPR will be of use in diverse microbiota engineering applications.
A RGS7-CaMKII complex drives myocyte-intrinsic and myocyte-extrinsic mechanisms of chemotherapy-induced cardiotoxicity
Authors: Basak Madhuri , Sengar Abhishek Singh , Das Kiran , Mahata Tarun , Kumar Manish , Kumar Dinesh , Biswas Sayan , Sarkar Subhasish , Kumar Pranesh , Das Priyadip , Stewart Adele , Maity Biswanath
Published: December 2022

Dose-limiting cardiotoxicity remains a major limitation in the clinical use of cancer chemotherapeutics. Here, we describe a role for Regulator of G protein Signaling 7 (RGS7) in chemotherapy-dependent heart damage, the demonstration for a functional role of RGS7 outside of the nervous system and retina. Though expressed at low levels basally, we observed robust up-regulation of RGS7 in the human and murine myocardium following chemotherapy exposure. In ventricular cardiomyocytes (VCM), RGS7 forms a complex with Ca
2+
/calmodulin-dependent protein kinase (CaMKII) supported by key residues (K412 and P391) in the RGS domain of RGS7. In VCM treated with chemotherapeutic drugs, RGS7 facilitates CaMKII oxidation and phosphorylation and CaMKII-dependent oxidative stress, mitochondrial dysfunction, and apoptosis. Cardiac-specific RGS7 knockdown protected the heart against chemotherapy-dependent oxidative stress, fibrosis, and myocyte loss and improved left ventricular function in mice treated with doxorubicin. Conversely, RGS7 overexpression induced fibrosis, reactive oxygen species generation, and cell death in the murine myocardium that were mitigated following CaMKII inhibition. RGS7 also drives production and release of the cardiokine neuregulin-1, which facilitates paracrine communication between VCM and neighboring vascular endothelial cells (EC), a maladaptive mechanism contributing to VCM dysfunction in the failing heart. Importantly, while RGS7 was both necessary and sufficient to facilitate chemotherapy-dependent cytotoxicity in VCM, RGS7 is dispensable for the cancer-killing actions of these same drugs. These selective myocyte-intrinsic and myocyte-extrinsic actions of RGS7 in heart identify RGS7 as an attractive therapeutic target in the mitigation of chemotherapy-driven cardiotoxicity.
SUMO enhances unfolding of SUMO–polyubiquitin-modified substrates by the Ufd1/Npl4/Cdc48 complex
Authors: Lee Hyein G. , Lemmon Abigail A. , Lima Christopher D.
Published: December 2022

The Ufd1/Npl4/Cdc48 complex is a universal protein segregase that plays key roles in eukaryotic cellular processes. Its functions orchestrating the clearance or removal of polyubiquitylated targets are established; however, prior studies suggest that the complex also targets substrates modified by the ubiquitin-like protein SUMO. Here, we show that interactions between Ufd1 and SUMO enhance unfolding of substrates modified by SUMO–polyubiquitin hybrid chains by the budding yeast Ufd1/Npl4/Cdc48 complex compared to substrates modified by polyubiquitin chains, a difference that is accentuated when the complex has a choice between these substrates. Incubating Ufd1/Npl4/Cdc48 with a substrate modified by a SUMO–polyubiquitin hybrid chain produced a series of single-particle cryo-EM structures that reveal features of interactions between Ufd1/Npl4/Cdc48 and ubiquitin prior to and during unfolding of ubiquitin. These results are consistent with cellular functions for SUMO and ubiquitin modifications and support a physical model wherein Ufd1/Npl4/Cdc48, SUMO, and ubiquitin conjugation pathways converge to promote clearance of proteins modified with SUMO and polyubiquitin.
The spreading rate dependence of the distribution of axial magma lenses along mid-ocean ridges
Authors: Liu Zhonglan , Buck W. Roger
Published: December 2022

Seismically imaged axial melt lenses (AMLs) are seen almost everywhere along the axis of fast-spreading ridges but at only a few localized segment centers on slow-spreading ridges. Standard models assuming that AMLs form when melt percolating upward pools where freezing produces an impermeable cap do not explain this fundamental observation. To tackle this long-standing problem, we combine a crustal density model and a thermal model with a recent mechanical model for sill formation. The mechanical model predicts that AMLs form below the axial lithosphere but only if the average density of the axial brittle lithosphere is not greater than the magma density. For standard thermal models, crustal density structures inferred from seismic velocity data and normal crustal thicknesses, AMLs are found to be stable along all of a ridge segment for spreading rates greater than about 50 mm/y. To explain slow-spreading observations, we assume that a share of the melt produced by the mantle upwelling all along a segment is focused to the segment center. Some of this melt partially crystallizes, releasing latent heat, before the evolved magma flows along the axis to build the crust away from the segment center. This “extra” heat, beyond what is supplied by the magma that builds the crust near the segment center, results in the lithosphere thin enough for stable melt lenses at the segment center. Our results are consistent with observations and offer a quantitative explanation of the marked difference in the distribution of AMLs along fast- versus slow-spreading centers.
Manganese-dependent microRNA trimming by 3′→5′ exonucleases generates 14-nucleotide or shorter tiny RNAs
Authors: Sim GeunYoung , Kehling Audrey C. , Park Mi Seul , Secor Jackson , Divoky Cameron , Zhang Huaqun , Malhotra Nipun , Bhagdikar Divyaa , Abd El-Wahab Ekram W. , Nakanishi Kotaro
Published: December 2022

MicroRNAs (miRNAs) are about 22-nucleotide (nt) noncoding RNAs forming the effector complexes with Argonaute (AGO) proteins to repress gene expression. Although tiny RNAs (tyRNAs) shorter than 19 nt have been found to bind to plant and vertebrate AGOs, their biogenesis remains a long-standing question. Here, our in vivo and in vitro studies show several 3′→5′ exonucleases, such as interferon-stimulated gene 20 kDa (ISG20), three prime repair exonuclease 1 (TREX1), and ERI1 (enhanced RNAi, also known as 3′hExo), capable of trimming AGO-associated full-length miRNAs to 14-nt or shorter tyRNAs. Their guide trimming occurs in a manganese-dependent manner but independently of the guide sequence and the loaded four human AGO paralogs. We also show that ISG20-mediated guide trimming makes Argonaute3 (AGO3) a slicer. Given the high Mn
2+
concentrations in stressed cells, virus-infected cells, and neurodegeneration, our study sheds light on the roles of the Mn
2+
-dependent exonucleases in remodeling gene silencing.
Lipid kinase PIK3C3 maintains healthy brown and white adipose tissues to prevent metabolic diseases
Authors: Song Wenqiang , Postoak J. Luke , Yang Guan , Guo Xingyi , Pua Heather H. , Bader Jackie , Rathmell Jeffrey C. , Kobayashi Hanako , Haase Volker H. , Leaptrot Katrina L. , Schrimpe-Rutledge Alexandra C. , Sherrod Stacy D. , McLean John A. , Zhang Jianhua , Wu Lan , Van Kaer Luc
Published: December 2022

Adequate mass and function of adipose tissues (ATs) play essential roles in preventing metabolic perturbations. The pathological reduction of ATs in lipodystrophy leads to an array of metabolic diseases. Understanding the underlying mechanisms may benefit the development of effective therapies. Several cellular processes, including autophagy and vesicle trafficking, function collectively to maintain AT homeostasis. Here, we investigated the impact of adipocyte-specific deletion of the lipid kinase phosphatidylinositol 3-kinase catalytic subunit type 3 (PIK3C3) on AT homeostasis and systemic metabolism in mice. We report that PIK3C3 functions in all ATs and that its absence disturbs adipocyte autophagy and hinders adipocyte differentiation, survival, and function with differential effects on brown and white ATs. These abnormalities cause loss of white ATs, whitening followed by loss of brown ATs, and impaired “browning” of white ATs. Consequently, mice exhibit compromised thermogenic capacity and develop dyslipidemia, hepatic steatosis, insulin resistance, and type 2 diabetes. While these effects of PIK3C3 largely contrast previous findings with the autophagy-related (ATG) protein ATG7 in adipocytes, mice with a combined deficiency in both factors reveal a dominant role of the PIK3C3-deficient phenotype. We have also found that dietary lipid excess exacerbates AT pathologies caused by PIK3C3 deficiency. Surprisingly, glucose tolerance is spared in adipocyte-specific PIK3C3-deficient mice, a phenotype that is more evident during dietary lipid excess. These findings reveal a crucial yet complex role for PIK3C3 in ATs, with potential therapeutic implications.
High-speed imaging reveals the bimodal nature of dense core vesicle exocytosis
Authors: Zhang Pengcheng , Rumschitzki David , Edwards Robert H.
Published: December 2022

During exocytosis, the fusion of secretory vesicle with plasma membrane forms a pore that regulates release of neurotransmitter and peptide. Heterogeneity of fusion pore behavior has been attributed to stochastic variation in a common exocytic mechanism, implying a lack of biological control. Using a fluorescent false neurotransmitter (FFN), we imaged dense core vesicle (DCV) exocytosis in primary mouse adrenal chromaffin cells by total internal reflection fluorescence microscopy at millisecond resolution and observed strikingly divergent modes of release, with fast events lasting <30 ms and slow events persisting for seconds. Dual imaging of slow events shows a delay in the entry of external dye relative to FFN release, suggesting exclusion by an extremely narrow pore <1 nm in diameter. Unbiased comprehensive analysis shows that the observed variation cannot be explained by stochasticity alone, but rather involves distinct mechanisms, revealing the bimodal nature of DCV exocytosis. Further, loss of calcium sensor synaptotagmin 7 increases the proportion of slow events without changing the intrinsic properties of either class, indicating the potential for independent regulation. The identification of two distinct mechanisms for release capable of independent regulation suggests a biological basis for the diversity of fusion pore behavior.
Electrical discharge triggers quasicrystal formation in an eolian dune
Authors: Bindi Luca , Pasek Matthew A. , Ma Chi , Hu Jinping , Cheng Guangming , Yao Nan , Asimow Paul D. , Steinhardt Paul J.
Published: December 2022

We report the discovery of a dodecagonal quasicrystal Mn
72.3
Si
15.6
Cr
9.7
Al
1.8
Ni
0.6
—composed of a periodic stacking of atomic planes with quasiperiodic translational order and 12-fold symmetry along the two directions perpendicular to the planes—accidentally formed by an electrical discharge event in an eolian dune in the Sand Hills near Hyannis, Nebraska, United States. The quasicrystal, coexisting with a cubic crystalline phase with composition Mn
68.9
Si
19.9
Ni
7.6
Cr
2.2
Al
1.4
, was found in a fulgurite consisting predominantly of fused and melted sand along with traces of melted conductor metal from a nearby downed power line. The fulgurite may have been created by a lightning strike that combined sand with material from downed power line or from electrical discharges from the downed power line alone. Extreme temperatures of at least 1,710 °C were reached, as indicated by the presence of SiO
2
glass in the sample. The dodecagonal quasicrystal is an example of a quasicrystal of any kind formed by electrical discharge, suggesting other places to search for quasicrystals on Earth or in space and for synthesizing them in the laboratory.
Glutamate–GABA imbalance mediated by miR-8-5p and its STTM regulates phase-related behavior of locusts
Authors: Yang Meiling , Du Baozhen , Xu Lingling , Wang Huimin , Wang Yanli , Lin Ke , He Guofei , Kang Le
Published: December 2022

The aggregation of locusts from solitary to gregarious phases is crucial for the formation of devastating locust plagues. Locust management requires research on the prevention of aggregation or alternative and greener solutions to replace insecticide use, and insect-derived microRNAs (miRNAs) show the potential for application in pest control. Here, we performed a genome-wide screen of the differential expression of miRNAs between solitary and gregarious locusts and showed that miR-8-5p controls the γ-aminobutyric acid (GABA)/glutamate functional balance by directly targeting glutamate decarboxylase (Gad). Blocking glutamate–GABA neurotransmission by miR-8-5p overexpression or
Gad
RNAi in solitary locusts decreased GABA production, resulting in locust aggregation behavior. Conversely, activating this pathway by miR-8-5p knockdown in gregarious locusts induced GABA production to eliminate aggregation behavior. Further results demonstrated that ionotropic glutamate/GABA receptors tuned glutamate/GABA to trigger/hamper the aggregation behavior of locusts. Finally, we successfully established a transgenic rice line expressing the miR-8-5p inhibitor by short tandem target mimic (STTM). When locusts fed on transgenic rice plants,
Gad
transcript levels in the brain increased greatly, and aggregation behavior was lost. This study provided insights into different regulatory pathways in the phase change of locusts and a potential control approach through behavioral regulation in insect pests.
Endogenous tagging of multiple cellular components in the sea anemone
Nematostella vectensis
Authors: Paix Alexandre , Basu Soham , Steenbergen Peter , Singh Rajwinder , Prevedel Robert , Ikmi Aissam
Published: December 2022

The cnidarian
Nematostella vectensis
has developed into a powerful model system to study the mechanisms underlying animal development, regeneration, and evolution. However, despite the significant progress in the molecular and genetic approaches in this sea anemone, endogenous protein tagging is still challenging. Here, we report a robust method for knock in for
Nematostella
using CRISPR/Cas9. As an outcome, we generate endogenously tagged proteins that label core molecular components of several cellular apparatus, including the nuclear envelope, cytoskeleton, cell adhesion, endoplasmic reticulum, cell trafficking, and extracellular matrix. Using live imaging, we monitor the dynamics of vesicular trafficking and endoplasmic reticulum in embryos, as well as cell contractility during the peristaltic wave of a primary polyp. This advancement in gene editing expands the molecular tool kit of
Nematostella
and enables experimental avenues to interrogate the cell biology of cnidarians.
Humanized V(D)J-rearranging and TdT-expressing mouse vaccine models with physiological HIV-1 broadly neutralizing antibody precursors
Authors: Luo Sai , Jing Changbin , Ye Adam Yongxin , Kratochvil Sven , Cottrell Christopher A. , Koo Ja-Hyun , Chapdelaine Williams Aimee , Francisco Lucas Vieira , Batra Himanshu , Lamperti Edward , Kalyuzhniy Oleksandr , Zhang Yuxiang , Barbieri Alessandro , Manis John P. , Haynes Barton F. , Schief William R. , Batista Facundo D. , Tian Ming , Alt Frederick W.
Published: December 2022

Antibody heavy chain (HC) and light chain (LC) variable region exons are assembled by V(D)J recombination. V(D)J junctional regions encode complementarity-determining-region 3 (CDR3), an antigen-contact region immensely diversified through nontemplated nucleotide additions (“N-regions”) by terminal deoxynucleotidyl transferase (TdT). HIV-1 vaccine strategies seek to elicit human HIV-1 broadly neutralizing antibodies (bnAbs), such as the potent CD4-binding site VRC01-class bnAbs. Mice with primary B cells that express receptors (BCRs) representing bnAb precursors are used as vaccination models. VRC01-class bnAbs uniformly use human HC V
H
1-2 and commonly use human LCs Vκ3-20 or Vκ1-33 associated with an exceptionally short 5-amino-acid (5-aa) CDR3. Prior VRC01-class models had nonphysiological precursor levels and/or limited precursor diversity. Here, we describe VRC01-class rearranging mice that generate more physiological primary VRC01-class BCR repertoires via rearrangement of V
H
1-2, as well as Vκ1-33 and/or Vκ3-20 in association with diverse CDR3s. Human-like TdT expression in mouse precursor B cells increased LC CDR3 length and diversity and also promoted the generation of shorter LC CDR3s via N-region suppression of dominant microhomology-mediated Vκ-to-Jκ joins. Priming immunization with eOD-GT8 60mer, which strongly engages VRC01 precursors, induced robust VRC01-class germinal center B cell responses. Vκ3-20-based responses were enhanced by N-region addition, which generates Vκ3-20-to-Jκ junctional sequence combinations that encode VRC01-class 5-aa CDR3s with a critical E residue. VRC01-class-rearranging models should facilitate further evaluation of VRC01-class prime and boost immunogens. These new VRC01-class mouse models establish a prototype for the generation of vaccine-testing mouse models for other HIV-1 bnAb lineages that employ different HC or LC Vs.
Tension-dependent RHGF-1 recruitment to stress fibers drives robust spermathecal tissue contraction
Authors: Avivi Kela Shiri , Sethi Kriti , Tan Pei Yi , Suresh Danesha , Ong Hui Ting , Castaneda Perla G. , Amin Mustafi R. , Laviv Tal , Cram Erin J. , Faix Jan , Zaidel-Bar Ronen
Published: December 2022

Contractile epithelial tubes are found in various organs, such as lung airways and blood capillaries. Their ability to sense luminal pressure and respond with adequate contractility is essential for their physiology, and its mis-regulation results in diseases such as asthma and hypertension. Here, we describe a mechanoresponsive regulatory pathway downstream of tissue stretching that controls contraction of the C. elegans spermatheca, a tubular structure where fertilization occurs. Using live-imaging, we show that ovulation-induced stretching of spermathecal cells leads to recruitment of the RhoGEF RHGF-1 to stress fibers, which activates RHO-1 and myosin II in a positive feedback loop. Through deletion analysis, we identified the PDZ domain of RHGF-1 as responsible for F-actin binding, and genetic epistasis analysis with the RhoGAP spv-1 demonstrated that tension-dependent recruitment of RHGF-1 to F-actin is required for robust spermathecal contractility. Our study illustrates how mechanosensitive regulators of Rho GTPases provide epithelial tubes the ability to tune their contractility in response to internal pressure.
Investigation of heavy ion irradiation effects on a charge trapping memory capacitor by C–V measurement
Authors: Chen Qiyu , Yang Xirong , Li Zongzhen , Bi Jinshun , Xi Kai , Zhang Zhenxing , Zhai Pengfei , Sun Youmei , Liu Jie
Published: December 2022

Heavy ion irradiation effects on charge trapping memory (CTM) capacitors with TiN/Al2O3/HfO2/Al2O3/HfO2/SiO2/p-Si structure have been investigated. The ion-induced interface charges and oxide trap charges were calculated and analyzed by capacitance–voltage (C–V) characteristics. The C–V curves shift towards the negative direction after swift heavy ion irradiation, due to the net positive charges accumulating in the trapping layer. The memory window decreases with the increase of ion fluence at high voltage, which results from heavy ion-induced structural damage in the blocking layer. The mechanism of heavy ion irradiation effects on CTM capacitors is discussed in detail with energy band diagrams. The results may help to better understand the physical mechanism of heavy ion-induced degradation of CTM capacitors.
Negative but Not Positive Alcohol-Related Consequences Tend to Occur Above the Heavy Episodic Drinking Threshold: A Daily Study of Young Adult Heavy Drinkers
Authors: Merrill Jennifer E , Labhart Florian , Perks Siobhan N
Published: December 2022

Aims

This study used event-level data to identify the threshold (i.e. number of standard alcoholic drinks) at which specific negative and positive alcohol-related consequences are likely to occur.

Methods

Ninety-six college students aged 18–20 reporting weekly heavy episodic drinking (HED) or at least one negative alcohol-related consequence in the past 2 weeks completed ecological momentary assessment over 28 days. Participants reported number of standard drinks consumed and negative (e.g. nausea) and positive (e.g. new friend) alcohol-related consequences on 492 drinking nights. The area under the receiver operating characteristic (AUROC) curve measured the ability of an increasing number of drinks consumed to discriminate between nights with versus without a given consequence. The Youden Index method was used to identify the optimal threshold of drinks for each consequence. Thresholds were examined for each consequence by participants’ biological sex and heavy drinking status.

Results

Across subgroups, most consequences occurred on nights where participants reported higher consumption levels relative to nights where consequences did not occur. Thresholds for negative consequences ranged between four and nine drinks and thresholds for positive consequences were between three and six drinks.

Conclusions

Many negative consequences are likely to occur following the traditional HED threshold of 4+/5+ drinks (females/males), with more severe consequences occurring at slightly higher thresholds. Positive consequences are likely to occur at lower thresholds. There may be an optimal number of drinks that maximize positive while minimizing negative consequences for heavy drinking college students.
Response of seed germination and seedling emergence ofHaloxylon ammodendronto rain frequency and temperature change from four desert ecosystems, Northwest China
Authors: Zhu Yajuan , Jia Zhiqing , Wang Guoje , Ning Husen , Ji Xiaomin , Luo Qinghong
Published: December 2022

Climate change will result in variation of rain frequency and amount and warming in arid zones, which is expected to affect seed germination and seedling emergence in desert ecosystems. However, the effects of unpredictable rainfall and increasing temperature on seed germination and seedling emergence of dominant desert plants remain unclear across different deserts, which are important for population regeneration and community succession in desert ecosystems. Seed germination and seedling emergence of Haloxylon ammodendron across four deserts in Northwest China were examined at different rain frequencies with same total amount, and constant and alternating temperatures, to investigate their response to climate change. Rain frequency determined seed germination and seedling emergence of H. ammodendron in the Tengger Desert, Badain Jaran Desert, Gurbantonggut Desert and Mutthar Desert, which was maximal at rain frequency of 10 times per month and decreased with a decrease of rain frequency. Temperature was not a restricting factor for seed germination of H. ammodendron in the Tengger Desert, Badain Jaran Desert and Gurbantonggut Desert, varying from 10 °C to 25 °C and from 20/10 °C to 30/15 °C, respectively. However, the highest temperature of 25 °C and 30/15 °C inhibited seed germination of H. ammodendron in the Mutthar Desert. Thus, H. ammodendron has an opportunistic germination strategy. Under climate change in the future, seed germination and seedling emergence of H. ammodendron would be restricted by the combination of less frequent rainfall and increased temperature in desert ecosystems. The regeneration of the H. ammodendron community should be promoted by irrigation and seedling transplant.
Genes related to cell wall metabolisms are targeted by miRNAs in immature tomato fruits under drought stress
Authors: Asakura Hiroko , Tanaka Mayui , Tamura Tomoko , Saito Yoshikazu , Yamakawa Takashi , Abe Keiko , Asakura Tomiko
Published: December 2022

The metabolism of tomato fruits changes when plants experience drought stress. In this study, we investigated changes in microRNA (miRNA) abundance and detected 32 miRNAs whose expression changes in fruit. The candidate target genes for each miRNA were predicted from the differentially expressed genes identified by transcriptome analysis at the same fruit maturation stage. The predicted targeted genes were related to cell wall metabolisms, response to pathogens, and plant hormones. Among these, we focused on cell wall metabolism-related genes and performed a dual luciferase assay to assess the targeting of their mRNAs by their predicted miRNA. As a result, sly-miR10532 and sly-miR7981e suppress the expression of mRNAs of galacturonosyltransferase-10 like encoding the main enzyme of pectin biosynthesis, while sly-miR171b-5p targets β-1,3-glucosidase mRNAs involved in glucan degradation. These results will allow the systematic characterization of miRNA and their target genes in the tomato fruit under drought stress conditions.