Self-Limiting Phase Transition Enabling Reversible Overstoichiometric Li Storage in Ni-Rich Cathodes.

Ni-rich cathodes are some of the most promising candidates for advanced lithium-ion batteries, but their available capacities have been stagnant due to the intrinsic Li+ storage sites. Extending the voltage window down can induce the phase transition from O3 to 1T of LiNiO2-derived cathodes to accommodate excess Li+ and dramatically increase the capacity. By setting the discharge cutoff voltage of LiNi0.6Co0.2Mn0.2O2 to 1.4 V, we can reach an extremely high capacity of 393 mAh g-1 and an energy density of 1070 Wh kg-1 here. However, the phase transition causes fast capacity decay and related structural evolution is rarely understood, hindering the utilization of this feature. We find that the overlithiated phase transition is self-limiting, which will transform into solid-solution reaction with cycling and make the cathode degradation slow down. This is attributed to the migration of abundant transition metal ions into lithium layers induced by the overlithiation, allowing the intercalation of overstoichiometric Li+ into the crystal without the O3 framework change. Based on this, the wide-potential cycling stability is further improved via a facile charge-discharge protocol. This work provides deep insight into the overstoichiometric Li+ storage behaviors in conventional layered cathodes and opens a new avenue toward high-energy batteries.

Effects of warming on rice production and metabolism process associated with greenhouse gas emissions.

Evaluating the impact of global warming on rice production and greenhouse gas (GHG) emissions is critical for ensuring food security and mitigating the consequences of climate change. Nonetheless, the impacts of warming on crop production, GHG emissions, and microbial mechanisms in the single-cropping rice systems remain unclear. Here, a two-year field experiment was conducted to explore the effects of warming (increased by 2.7-3.0 °C on average) in the rice growing season on crop production and functional microorganisms associated with GHG emissions. Results showed that warming resulted in significant reduction (p < 0.01) in the aboveground biomass and grain yield as well as in grain weight, the number of spikelets per panicle, and the seed-setting rate. However, it caused a significant increase (p < 0.01) in the number of panicles by 15.6 % and 34.9 %, respectively. Furthermore, warming significantly increased (p < 0.01) seasonal methane (CH4) emissions but reduced nitrous oxide (N2O) emissions, particularly in 2022.The relative abundance of genes associated with CH4 metabolism and nitrogen metabolism was increased by 40.7 % and 32.7 %, respectively, in response to warming. Moreover, warming had a positive impact on the abundance of genes related to CH4 production and oxidation processes but did not affect the denitrification processes associated with N2O production. These results showed that warming decreased rice yield and biomass in the single cropping rice system but increased CH4 emissions and global warming potential. Taken together, to address the increasing food demand of a growing population and mitigate the impacts of global warming, it is imperative to duce GHG emissions and enhance crop yields.

Ce-doping induces rapid electron transfer in a bimetallic phosphide heterostructure to achieve efficient hydrogen production.

Using electrochemical water splitting to generate hydrogen is considered a desirable approach, which is greatly impeded by the sluggish dissociation of H2O and adsorption and desorption of H*. Effective hydrogen production can be achieved by speeding up the chemical process with a suitable electrocatalyst. In this work, we designed and synthesized a rare earth element cerium (Ce) regulated iron-nickel bimetallic phosphide Ce-NiFeP@NF (here NiFeP represents Fe2P/NiP2) nanoarray with nanoflowers. For the hydrogen evolution reaction (HER), Ce-NiFeP@NF only needs an overpotential of 106 mV to provide a current density of 10 mA cm-2, compared to NiFeP@NF (175 mV@10 mA cm-2). This self-supported electrocatalyst Ce-NiFeP@NF with a composite morphology exhibits excellent performance in the HER. Specifically, the introduction of Ce promotes the electron transfer process at the Fe2P/NiP2 heterojunction interface and the Ce-NiFeP@NF nanocomposite structure with nanoflowers has a larger electrochemically active specific surface area, which is more conducive to improving the intrinsic catalytic activity. Also, a dual-electrode alkaline electrolytic cell (Ce-NiFeP@NF functions as both the anode and the cathode) operates with a cell voltage of only 1.56 V to achieve a current density of 10 mA cm-2. The synergistic effect of rare earth element doping and heterojunction engineering can improve the morphology of intrinsic catalysts to achieve more efficient electrochemical water splitting for hydrogen production.

Generation of Spatiotemporal Vortex Pulses by Resonant Diffractive Grating.

Spatiotemporal vortex pulses are wave packets that carry transverse orbital angular momentum, exhibiting exotic structured wave fronts that can twist through space and time. Existing methods to generate these pulses require complex setups like spatial light modulators or computer-optimized structures. Here, we demonstrate a new approach to generate spatiotemporal vortex pulses using just a simple diffractive grating. The key is constructing a phase vortex in frequency-momentum space by leveraging symmetry, resonance, and diffraction. Our approach is applicable to any wave system. We use a liquid surface wave (gravity wave) platform to directly demonstrate and observe the real-time generation and evolution of spatiotemporal vortex pulses. This straightforward technique provides opportunities to explore pulse dynamics and potential applications across different disciplines.

Exploiting Topological Darkness in Photonic Crystal Slabs for Spatiotemporal Vortex Generation.

Spatiotemporal optical vortices (STOVs) with swirling phase singularities in space and time hold great promise for a wide range of applications across diverse fields. However, current approaches to generate STOVs lack integrability and rely on bulky free-space optical components. Here, we demonstrate routine STOV generation by harnessing the topological darkness phenomenon of a photonic crystal slab. Complete polarization conversion enforced by symmetry enables topological darkness to arise from photonic bands of guided resonances, imprinting vortex singularities onto an ultrashort reflected pulse. Utilizing time-resolved spatial mapping, we provide the first observation of STOV generation using a photonic crystal slab, revealing the imprinted STOV structure manifested as a curved vortex line in the pulse profile in space and time. Our work establishes photonic crystal slabs as a versatile and accessible platform for engineering STOVs and harnessing the topological darkness in nanophotonics.

PDMS Film-Based Flexible Pressure Sensor Array with Surface Protruding Structure for Human Motion Detection and Wrist Posture Recognition.

Flexible pressure sensors have been widely concerned because of their great application potential in the fields of electronic skin, human-computer interaction, health detection, and so on. In this paper, a flexible pressure sensor is designed, with polydimethylsiloxane (PDMS) films with protruding structure as elastic substrate and poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT:PSS)/cellulose nanocrystals (CNC) as conductive-sensitive material. The flexible pressure sensor has a wide linear detection range (0-100 kPa), outstanding sensitivity (2.32 kPa-1), and stability of more than 2000 cycles. The sensor has been proven to be able to detect a wide range of human movements (finger bending, elbow bending, etc.) and small movements (breathing, pulse, etc.). In addition, the pressure sensor array can detect the pressure distribution and judge the shape of the object. A smart wristband equipped with four flexible pressure sensors is designed. Among them, the k-nearest neighbor (KNN) algorithm is used to classify sensor data to achieve high accuracy (99.52%) recognition of seven kinds of wrist posture. This work provides a new opportunity to fabricate simple, flexible pressure sensors with potential applications in the next-generation electronic skin, health detection, and intelligent robotics.

A novel transformer autoencoder for multi-modal emotion recognition with incomplete data.

Multi-modal signals have become essential data for emotion recognition since they can represent emotions more comprehensively. However, in real-world environments, it is often impossible to acquire complete data on multi-modal signals, and the problem of missing modalities causes severe performance degradation in emotion recognition. Therefore, this paper represents the first attempt to use a transformer-based architecture, aiming to fill the modality-incomplete data from partially observed data for multi-modal emotion recognition (MER). Concretely, this paper proposes a novel unified model called transformer autoencoder (TAE), comprising a modality-specific hybrid transformer encoder, an inter-modality transformer encoder, and a convolutional decoder. The modality-specific hybrid transformer encoder bridges a convolutional encoder and a transformer encoder, allowing the encoder to learn local and global context information within each particular modality. The inter-modality transformer encoder builds and aligns global cross-modal correlations and models long-range contextual information with different modalities. The convolutional decoder decodes the encoding features to produce more precise recognition. Besides, a regularization term is introduced into the convolutional decoder to force the decoder to fully leverage the complete and incomplete data for emotional recognition of missing data. 96.33%, 95.64%, and 92.69% accuracies are attained on the available data of the DEAP and SEED-IV datasets, and 93.25%, 92.23%, and 81.76% accuracies are obtained on the missing data. Particularly, the model acquires a 5.61% advantage with 70% missing data, demonstrating that the model outperforms some state-of-the-art approaches in incomplete multi-modal learning.

Sixty Years of Frequency-Domain Monaural Speech Enhancement: From Traditional to Deep Learning Methods.

Frequency-domain monaural speech enhancement has been extensively studied for over 60 years, and a great number of methods have been proposed and applied to many devices. In the last decade, monaural speech enhancement has made tremendous progress with the advent and development of deep learning, and performance using such methods has been greatly improved relative to traditional methods. This survey paper first provides a comprehensive overview of traditional and deep-learning methods for monaural speech enhancement in the frequency domain. The fundamental assumptions of each approach are then summarized and analyzed to clarify their limitations and advantages. A comprehensive evaluation of some typical methods was conducted using the WSJ + Deep Noise Suppression (DNS) challenge and Voice Bank + DEMAND datasets to give an intuitive and unified comparison. The benefits of monaural speech enhancement methods using objective metrics relevant for normal-hearing and hearing-impaired listeners were evaluated. The objective test results showed that compression of the input features was important for simulated normal-hearing listeners but not for simulated hearing-impaired listeners. Potential future research and development topics in monaural speech enhancement are suggested.

Stimulus-responsive proteins involved in multi-process regulation of storage substance accumulation during rice grain filling under elevated temperature.

BACKGROUND: The intensified global warming during grain filling deteriorated rice quality, in particular increasing the frequency of chalky grains which markedly impact market value. The formation of rice quality is a complex process influenced by multiple genes, proteins and physiological metabolic processes. Proteins responsive to stimulus can adjust the ability of plants to respond to unfavorable environments, which may be an important protein involved in the regulation of quality formation under elevated temperature. However, relatively few studies have hindered our further understanding of rice quality formation under elevated temperature. RESULTS: We conducted the actual field elevated temperature experiment and performed proteomic analysis of rice grains at the early stage of grain filling. Starting with the response to stimulus in GO annotation, 22 key proteins responsive to stimulus were identified in the regulation of grain filling and response to elevated temperature. Among the proteins responsive to stimulus, during grain filling, an increased abundance of signal transduction and other stress response proteins, a decreased abundance of reactive oxygen species-related proteins, and an increased accumulation of storage substance metabolism proteins consistently contributed to grain filling. However, the abundance of probable indole-3-acetic acid-amido synthetase GH3.4, probable indole-3-acetic acid-amido synthetase GH3.8 and CBL-interacting protein kinase 9 belonged to signal transduction were inhibited under elevated temperature. In the reactive oxygen species-related protein, elevated temperature increased the accumulation of cationic peroxidase SPC4 and persulfide dioxygenase ETHE1 homolog to maintain normal physiological homeostasis. The increased abundance of alpha-amylase isozyme 3E and seed allergy protein RA5 was related to the storage substance metabolism, which regulated starch and protein accumulation under elevated temperature. CONCLUSION: Auxin synthesis and calcium signal associated with signal transduction, other stress responses, protein transport and modification, and reactive oxygen species-related proteins may be key proteins responsive to stimulus in response to elevated temperature. Alpha-amylase isozyme 3E and seed allergy protein RA5 may be the key proteins to regulate grain storage substance accumulation and further influence quality under elevated temperature. This study enriched the regulatory factors involved in the response to elevated temperature and provided a new idea for a better understanding of grain response to temperature.

Iodine revisited: If and how inorganic iodine species can be measured reliably and what cause their conversions in water?

This study revisited a list of inorganic iodine species on their detections and conversions under different water conditions. Several surprising results were found, e.g., UV-vis spectrophotometry is the only reliable method for I3- and I2 determinations with coexisting I-/IO3-/IO4-, while alkaline eluent of IC and LC columns can convert them into I- completely; IO4- can be converted into IO3- completely in IC columns and partly in LC columns; a small portion of IO3- was reduced to I- in LC columns. To avoid errors, a method for detecting multiple coexisting iodine species is suggested as follows: firstly, detecting I3- and I2 via UV-vis spectrophotometry; then, analyzing IO4- (> 0.2 mg/L) through LC; and lastly, obtaining I- and IO3- concentrations by deducting I- and IO3- measured by IC from the signals derived from I3-/I2/IO4-. As for stability, I- or IO3- alone is stable, but mixing them up generates I2 or H2OI+ under acidic conditions. Although IO4- is stable within pH 4.0-8.0, it becomes H5IO6/H3IO62- in strongly acidic/alkaline solutions. Increasing pH accelerates the conversions of I3- and I2 into I- under basic conditions, whereas dissolved oxygen and dosage exert little effect. Additionally, spiking ICl into water produces I2 and IO3- rather than HIO.

Homolog of Human placenta-specific gene 8, PcPLAC8-10, enhances cadmium uptake by Populus roots.

Cadmium (Cd) pollution of soil occurs worldwide. Phytoremediation is an effective approach for cleaning up Cd polluted soil. Fast growing Populus species with high Cd uptake capacities are desirable for phytoremediation. Thus, it is important to elucidate the molecular functions of genes involved in Cd uptake by poplars. In this study, PcPLAC8-10, a homolog of Human placenta-specific gene 8 (PLAC8) implicated in Cd transport was functionally characterized in Populus × canescens. PcPLAC8-10 was transcriptionally induced in Cd-treated roots and it encoded a plasma membrane-localized transporter. PcPLAC8-10 exhibited Cd uptake activity when expressed in yeast cells. No difference in growth was observed between wild type (WT) and PcPLAC8-10-overexpressing poplars. PcPLAC8-10-overexpressing poplars exhibited increases in net Cd2+ influxes by 192% and Cd accumulation by 57% in the roots. However, similar reductions in biomass were found in WT and transgenic poplars when exposed to Cd. The complete motif of CCXXXXCPC in PcPLAC8-10 was essential for its Cd transport activity. These results suggest that PcPLAC8-10 is a plasma membrane-localized transporter responsible for Cd uptake in the roots and the complete CCXXXXCPC motif of PcPLAC8-10 plays a key role in its Cd transport activity in poplars.

Mitigating the adverse effect of warming on rice canopy and rhizosphere microbial community by nitrogen application: An approach to counteract future climate change for rice.

The adverse impact of climate change on crop production continues to increase, necessitating the development of suitable strategies to mitigate these effects and improve food security. Several studies have revealed how global warming negatively impacts the grain-filling stage of rice and that this effect could be mitigated by nitrogen; however, the impact of nitrogen application on rice canopy and rhizosphere microbial communities remains unclear. We conducted a study using an open-field warming system. Results showed that warming influenced rice canopy by decreasing aboveground biomass and harvest index, whereas nitrogen application had positive effect on rice production under warming conditions by increasing the plant nitrogen content, biomass, harvest index and soil fertilities. Moreover, soil ammonium nitrogen (NH4+-N) and nitrate nitrogen (NO3--N) contents were significantly decreased under warming, which were higher after nitrogen application. Notably, warming and nitrogen fertilizer caused 19 % (P < 0.01) and 7 % (P < 0.05) variations, respectively, in the ß diversity of the microbial community, respectively. The impact of warming was significant on NH4+-N-related microorganisms; however, this impact was weakened by nitrogen application for microbes in the rhizosphere. This study demonstrated that enhanced nitrogen fertilizer can alleviate the adverse impact of warming by weakening its effects on rhizosphere microbes, improving soil fertility, promoting rice nitrogen uptake, and increasing the aboveground biomass and harvest index. These findings provide an important theoretical basis for developing practical, responsive cultivation strategies.

Visualizing single-molecule conformational transition and binding dynamics of intrinsically disordered proteins.

Intrinsically disordered proteins (IDPs) play crucial roles in cellular processes and hold promise as drug targets. However, the dynamic nature of IDPs remains poorly understood. Here, we construct a single-molecule electrical nanocircuit based on silicon nanowire field-effect transistors (SiNW-FETs) and functionalize it with an individual disordered c-Myc bHLH-LZ domain to enable label-free, in situ, and long-term measurements at the single-molecule level. We use the device to study c-Myc interaction with Max and/or small molecule inhibitors. We observe the self-folding/unfolding process of c-Myc and reveal its interaction mechanism with Max and inhibitors through ultrasensitive real-time monitoring. We capture a relatively stable encounter intermediate ensemble of c-Myc during its transition from the unbound state to the fully folded state. The c-Myc/Max and c-Myc/inhibitor dissociation constants derived are consistent with other ensemble experiments. These proof-of-concept results provide an understanding of the IDP-binding/folding mechanism and represent a promising nanotechnology for IDP conformation/interaction studies and drug discovery.

Multiple regulators were involved in glutelin synthesis and subunit accumulation in response to temperature and nitrogen during rice grain-filling stage.

Rice glutelin is sensitive to temperature and nitrogen, however, the regulatory mechanism of glutelin response to temperature and nitrogen is unclear. In this study, we conducted the open field warming experiment by the Free-air temperature enhancement facility and application of nitrogen during grain filling. In three-year field warming experiments, glutelin relative content was significantly increased under elevated temperature and application of nitrogen. Temperature and nitrogen and their interaction increased the glutelin accumulation rate in the early and middle grain filling stages (10-25d after flowering), but decreased the glutelin accumulation rate in the middle and late grain filling stages (25-45d after flowering). Elevated temperature promoted pro-glutelin levels whereas application of nitrogen under warming increased the amount of α-glutelin. At the transcriptional level, the expression levels of the glutelin-encoding genes and protein disulphide isomerase-like enzyme (PDIL1-1), glutelin precursor accumulation 4 (GPA4), glutelin precursor mutant 6 (GPA2), glutelin precursor accumulation 3 (GPA3) and vacuolar processing enzyme (OsVPE1) of glutelin folding, transport and accumulation-related genes were up-regulated by nitrogen under natural temperature as early as 5d after flowering. However, elevated temperature up-regulated glutelin-encoding genes before 20d after flowering, and the expression of endoplasmic reticulum chaperone (OsBip1), OsPDIL1-1, small GTPase gene (GPA1), GPA2-GPA4 and OsVPE1 were significantly increased post 20d after flowering under warming. In addition, the increase in glutelin content worsened grain quality, particularly chalkiness and eating quality. Overall, the results were helpful to understand glutelin accumulation and provide a theoretical basis for further study the relationship between rice quality and glutelin under global warming.

Realization of large transmitted Goos-Hänchen shifts with high (near 100%) transmittance based on a coupled double-layer grating system.

Achieving Goos-Hänchen shift enhancement with high transmittance or reflectance based on the resonance effect is challenging due to the drop in the resonance region. This Letter demonstrates the realization of large transmitted Goos-Hänchen shifts with high (near 100%) transmittance based on a coupled double-layer grating system. The double-layer grating is composed of two parallel and misaligned subwavelength dielectric gratings. By changing the distance and the relative dislocation between the two dielectric gratings, the coupling of the double-layer grating can be flexibly tuned. The transmittance of the double-layer grating can be close to 1 in the entire resonance angle region, and the gradient of the transmissive phase is also preserved. The Goos-Hänchen shift of the double-layer grating reaches ∼30 times the wavelength, approaching 1.3 times the radius of the beam waist, which can be observed directly.

Unique Morphology of Sarcobatus baileyi Male Inflorescence and Its Botanical Implications.

A typical angiosperm flower is usually bisexual, with entomophilous plants having four whorls of organs: the calyx, corolla, stamens, and gynoecium. The flower is usually colorful, and thus, distinct from the dull-colored reproductive organs of gymnosperms; however, this formula is not applicable to all flowers. For example, the male flower of Sarcobatus baileyi is reduced into only a single stamen. Such unusual flowers are largely poorly documented and underappreciated. To fill such a lacuna in our knowledge of the male reproductive organ of S. baileyi, we collected and studied materials of the male inflorescence of S. baileyi (Sarcobataceae). The outcomes of our Micro-CT (micro computed tomography), SEM (scanning electron microscopy), and paraffin sectioning indicate that a male inflorescence of S. baileyi is more comparable with the cone of conifers; its male flowers lack the perianth, are directly attached to a central axis and sheltered by peltate indusium-like shields. To understand the evolutionary logic underlying such a rarely seen male inflorescence, we also studied and compared it with a female cone of Cupressus sempervirens. Although the genera Sarcobatus and Cupressus belong to two distinct major plant groups (angiosperms and gymnosperms), they apply the same propagule-protecting strategy.

Chemical-Mechanical Robustness of Single-Crystalline Ni-Rich Cathode Enabled by Surface Atomic Arrangement Control.

Layered transition metal oxide cathodes have been one of the dominant cathodes for lithium-ion batteries with efficient Li+ intercalation chemistry. However, limited by the weak layered interaction and unstable surface, mechanical and chemical failure plagues their electrochemical performance, especially for Ni-rich cathodes. Here, adopting a simultaneous elemental-structural atomic arrangement control based on the intrinsic Ni-Co-Mn system, the surface role is intensively investigated. Within the invariant oxygen sublattice of the crystal, a robust surface with the synergistic concentration gradient and layered-spinel intertwined structure is constructed on the model single-crystalline Ni-rich cathode. With mechanical strain dissipation and chemical erosion suppression, the cathode exhibits an impressive capacity retention of 82 % even at the harsh 60 °C after 150 cycles at 1 C. This work highlights the coupling effect of structure and composition on the chemical-mechanical properties, and the concept will spur more researches on the cathodes that share the same sublattice.

High-efficiency nonlocal reflection-type vortex beam generation based on bound states in the continuum.

Momentum-space polarization vortices centered at symmetry-protected bound states in the continuum of a periodic structure, e.g. photonic crystal slab, provide a novel nonlocal approach to generate vortex beams. This approach enjoys a great convenience of no precise alignment requirements, although the generation efficiency of the nonlocal generators requires further optimization before the practical application. In this work, we propose a temporal-coupled-mode-theory-based guideline for high-efficiency nonlocal reflection-type vortex generator design. The conversion efficiency of the vortex beam is found to be limited by the ratio of the radiative loss to the intrinsic absorption in practical systems. To increase this ratio through mode selection and structure design, the photonic crystal slabs are theoretically designed and experimentally characterized, showing a maximum on-resonance conversion efficiency of up to 86%. Combining high efficiency with simple fabrication and no requirement for precise alignment, reflection-type photonic crystal slabs could offer a new and competitive way to generate vortex beams flexibly.

Stimuli-Induced Subconformation Transformation of the PSI-LHCI Protein at Single-Molecule Resolution.

Photosynthesis is a very important process for the current biosphere which can maintain such a subtle and stable circulatory ecosystem on earth through the transformation of energy and substance. Even though been widely studied in various aspects, the physiological activities, such as intrinsic structural vibration and self-regulation process to stress of photosynthetic proteins, are still not in-depth resolved in real-time. Herein, utilizing silicon nanowire biosensors with ultrasensitive temporal and spatial resolution, real-time responses of a single photosystem I-light harvesting complex I (PSI-LHCI) supercomplex of Pisum sativum to various conditions, including gradient variations in temperature, illumination, and electric field, are recorded. Under different temperatures, there is a bi-state switch process associated with the intrinsic thermal vibration behavior. When the variations of illumination and the bias voltage are applied, two additional shoulder states, probably derived from the self-conformational adjustment, are observed. Based on real-time monitoring of the dynamic processes of the PSI-LHCI supercomplex under various conditions, it is successively testified to promising nanotechnology for protein profiling and biological functional integration in photosynthesis studies.

Single-exonuclease nanocircuits reveal the RNA degradation dynamics of PNPase and demonstrate potential for RNA sequencing.

The degradation process of RNA is decisive in guaranteeing high-fidelity translation of genetic information in living organisms. However, visualizing the single-base degradation process in real time and deciphering the degradation mechanism at the single-enzyme level remain formidable challenges. Here, we present a reliable in-situ single-PNPase-molecule dynamic electrical detector based on silicon nanowire field-effect transistors with ultra-high temporal resolution. These devices are capable of realizing real-time and label-free monitoring of RNA analog degradation with single-base resolution, including RNA analog binding, single-nucleotide hydrolysis, and single-base movement. We discover a binding event of the enzyme (near the active site) with the nucleoside, offering a further understanding of the RNA degradation mechanism. Relying on systematic analyses of independent reads, approximately 80% accuracy in RNA nucleoside sequencing is achieved in a single testing process. This proof-of-concept sets up a Complementary Metal Oxide Semiconductor (CMOS)-compatible playground for the development of high-throughput detection technologies toward mechanistic exploration and single-molecule sequencing.