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Action potentials have a central role in the nervous system and in many cellular processes, notably those involving ion channels. The accurate measurement of action potentials requires efficient coupling between the cell membrane and the measuring electrodes. Intracellular recording methods such as patch clamping involve measuring the voltage or current across the cell membrane by accessing the cell interior with an electrode, allowing both the amplitude and shape of the action potentials to be recorded faithfully with high signal-to-noise ratios 1 . However, the invasive nature of intracellular methods usually limits the recording time to a few hours 1 , and their complexity makes it difficult to simultaneously record more than a few cells. Extracellular recording methods, such as multielectrode arrays 2 and multitransistor arrays 3 , are non-invasive and allow long-term and multiplexed measurements. However, extracellular recording sacrifices the one-to-one correspondence between the cells and electrodes, and also suffers from significantly reduced signal strength and quality. Extracellular techniques are not, therefore, able to record action potentials with the accuracy needed to explore the properties of ion channels. As a result, the pharmacological screening of ion-channel drugs is usually performed by low-throughput intracellular recording methods 4 . The use of nanowire transistors 5 , 6 , 7 , nanotube-coupled transistors 8 and micro gold-spine and related electrodes 9 , 10 , 11 , 12 can significantly improve the signal strength of recorded action potentials. Here, we show that vertical nanopillar electrodes can record both the extracellular and intracellular action potentials of cultured cardiomyocytes over a long period of time with excellent signal strength and quality. Moreover, it is possible to repeatedly switch between extracellular and intracellular recording by nanoscale electroporation and resealing processes. Furthermore, vertical nanopillar electrodes can detect subtle changes in action potentials induced by drugs that target ion channels. Arrays of vertical nanopillar electrodes can be used for both intracellular and extracellular recording with excellent signal strength and quality, and minimal damage to the cells.

Direct electrical recording and stimulation of neural activity using micro-fabricated silicon and metal micro-wire probes have contributed extensively to basic neuroscience and therapeutic applications; however, the dimensional and mechanical mismatch of these probes with the brain tissue limits their stability in chronic implants and decreases the neuron–device contact. Here, we demonstrate the realization of a three-dimensional macroporous nanoelectronic brain probe that combines ultra-flexibility and subcellular feature sizes to overcome these limitations. Built-in strains controlling the local geometry of the macroporous devices are designed to optimize the neuron/probe interface and to promote integration with the brain tissue while introducing minimal mechanical perturbation. The ultra-flexible probes were implanted frozen into rodent brains and used to record multiplexed local field potentials and single-unit action potentials from the somatosensory cortex. Significantly, histology analysis revealed filling-in of neural tissue through the macroporous network and attractive neuron–probe interactions, consistent with long-term biocompatibility of the device. An ultra-flexible cylindrical mesh embedding multiple electrodes bending away from the device is used to probe rodents’ neural activity in vivo . This geometry improves the neuron–probe contact and reduces tissue response in chronic applications.

Horse chestnut ( Aesculus chinensis ) is an important medicinal tree that contains various bioactive compounds, such as aescin, barrigenol-type triterpenoid saponins (BAT), and aesculin, a glycosylated coumarin. Herein, we report a 470.02 Mb genome assembly and characterize an Aesculus -specific whole-genome duplication event, which leads to the formation and duplication of two triterpenoid biosynthesis-related gene clusters (BGCs). We also show that AcOCS6 , AcCYP716A278 , AcCYP716A275 , and AcCSL1 genes within these two BGCs along with a seed-specific expressed AcBAHD6 are responsible for the formation of aescin. Furthermore, we identify seven Aesculus -originated coumarin glycoside biosynthetic genes and achieve the de novo synthesis of aesculin in E. coli . Collinearity analysis shows that the collinear BGC segments can be traced back to early-diverging angiosperms, and the essential gene-encoding enzymes necessary for BAT biosynthesis are recruited before the splitting of Aesculus , Acer , and Xanthoceras . These findings provide insight on the evolution of gene clusters associated with medicinal tree metabolites. Horse chestnut ( Aesculus chinensis ) is a tree species that can produce medicinal compounds such as aescin and aesculin. Here, the authors assemble its genome, identify key genes involved in the biosynthesis of these two group of compounds, and achieve the de novo synthesis of aesculin in E. coli .

Penetrating flexible electrode arrays can simultaneously record thousands of individual neurons in the brains of live animals. However, it has been challenging to spatially map and longitudinally monitor the dynamics of large three-dimensional neural networks. Here we show that optimized ultraflexible electrode arrays distributed across multiple cortical regions in head-fixed mice and in freely moving rats allow for months-long stable electrophysiological recording of several thousand neurons at densities of about 1,000 neural units per cubic millimetre. The chronic recordings enhanced decoding accuracy during optogenetic stimulation and enabled the detection of strongly coupled neuron pairs at the million-pair and millisecond scales, and thus the inference of patterns of directional information flow. Longitudinal and volumetric measurements of neural couplings may facilitate the study of large-scale neural circuits. Optimized ultraflexible electrode arrays enable months-long electrophysiological recordings of several thousand neurons at densities of up to 1,000 neural units per cubic millimetre.

Understanding brain functions at the circuit level requires time‐resolved simultaneous measurement of a large number of densely distributed neurons, which remains a great challenge for current neural technologies. In particular, penetrating neural electrodes allow for recording from individual neurons at high temporal resolution, but often have larger dimensions than the biological matrix, which induces significant damage to brain tissues and therefore precludes the high implant density that is necessary for mapping large neuronal populations with full coverage. Here, it is demonstrated that nanofabricated ultraflexible electrode arrays with cross‐sectional areas as small as sub‐10 µm2 can overcome this physical limitation. In a mouse model, it is shown that these electrodes record action potentials with high signal‐to‐noise ratio; their dense arrays allow spatial oversampling; and their multiprobe implantation allows for interprobe spacing at 60 µm without eliciting chronic neuronal degeneration. These results present the possibility of minimizing tissue displacement by implanted ultraflexible electrodes for scalable, high‐density electrophysiological recording that is capable of complete neuronal circuitry mapping over chronic time scales. Ultraflexible, miniaturized intracortical neural probes hosting arrays of individually addressable electrodes are realized by nanofabrication on substrate‐less device architecture. Smallest dimension and surgical footprint per electrode, the ability to detect and isolate action potentials, and chronically nondegrading tissue–probe interface at sub‐100 µm interprobe distance are demonstrated in a mouse model.

The throttling performance of conventional throttle orifice structures of fluid control valves is very low. Therefore, this paper proposes a novel trapezoidal throttle orifice with excellent throttling performance. The effect of the taper of the throttle orifice on the erosion was researched. Firstly, two schemes of trapezoidal throttle orifice were proposed according to the fluid control valve. Secondly, the excellent throttling performance of the trapezoidal throttle orifice was compared and optimized. Finally, a numerical simulation method of the erosion-resistant ability of the trapezoidal throttle orifice was established. It was found that for the same throttling area, the differential pressure of the trapezoidal orifice was higher than that of the conventional rectangular orifice by about 18.6%. The taper had little effect on the gas production, which increased by only 3.3% during the 10° to 30° change. The maximum erosion was firstly reduced and then increased with increases in the angle from 0 to 25°of the taper. Moreover, the minimum was achieved at about a 20° taper angle. The above research methods provide a theoretical basis for optimizing the size and structure of orifices and the sealing reliability of fluid control valves.

Heteroatom doping effectively tunes the electronic conductivity of transition metal selenides (TMSs) with rapid K+ accessibility in potassium ion batteries (PIBs). Although considerable efforts are dedicated to investigating the relationship between the doping strategy and the resulting electrochemistry, the doping mechanisms, especially in view of the ion and electronic diffusion kinetics upon cycling, are seldom elucidated systematically. Herein, the crystal structure stability, charge/ion state, and bandgap of the active materials are found to be precisely modulated by favorable heteroatom doping, resulting in intrinsically fast kinetics of the electrode materials. Based on the combined mechanisms of intercalation and conversion reactions, electron and K+ ion transfer in Ni‐doped CoSe2 embedded in carbon nanocomposites (Ni‐CoSe2@NC) can be significantly enhanced via electronic engineering. Benefiting from the synthetic controlled Ni grains, the heterointerface formed by the intermediate products of electrochemical reactions in Ni‐CoSe2@NC strengthens the conversion kinetics and interdiffusion process, developing a low‐barrier mesophase with optimized potassium storage. Overall, an electronic tuning strategy can offer deeper atomic insights into the conversion reaction of TMSs in PIBs. Heteroatom doping has a significant impact on boosting the performance of secondary battery systems. By engineering the electrodes with controllable composites, ionic and electronic diffusion kinetics are simultaneously obtained. The underlying electrochemical K storage mechanisms based on the intercalation/deintercalation and conversion reactions are illustrated in detail by electrochemical kinetic analysis, theoretical calculations, and X‐ray absorption spectroscopy.

Blood vessels play a role in osteogenesis and osteoporosis; however, the role of vascular metabolism in these processes remains unclear. The present study finds that ovariectomized mice exhibit reduced blood vessel density in the bone and reduced expression of the endothelial glycolytic regulator pyruvate kinase M2 (PKM2). Endothelial cell (EC)‐specific deletion of Pkm2 impairs osteogenesis and worsens osteoporosis in mice. This is attributed to the impaired ability of bone mesenchymal stem cells (BMSCs) to differentiate into osteoblasts. Mechanistically, EC‐specific deletion of Pkm2 reduces serum lactate levels secreted by ECs, which affect histone lactylation in BMSCs. Using joint CUT&Tag and RNA sequencing analyses, collagen type I alpha 2 chain (COL1A2), cartilage oligomeric matrix protein (COMP), ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1), and transcription factor 7 like 2 (TCF7L2) as osteogenic genes regulated by histone H3K18la lactylation are identified. PKM2 overexpression in ECs, lactate addition, and exercise restore the phenotype of endothelial PKM2‐deficient mice. Furthermore, serum metabolomics indicate that patients with osteoporosis have relatively low lactate levels. Additionally, histone lactylation and related osteogenic genes of BMSCs are downregulated in patients with osteoporosis. In conclusion, glycolysis in ECs fuels BMSC differentiation into osteoblasts through histone lactylation, and exercise partially ameliorates osteoporosis by increasing serum lactate levels.

Stably representing recurring visual scenes is crucial for behavior. However, previous studies report varying degrees of gradual neural activity changes over time in slow dynamic (1-5 seconds) firing rate code. Here we show that temporal codes, which capture structures in visually evoked fast (tens of milliseconds) spiking patterns, support the stability of visual representations. We tracked the spiking responses of the same visual cortical populations in male mice for 15 consecutive days using custom-developed, large-scale, ultraflexible electrode arrays. Across various stimuli, neurons exhibited different day-to-day stability in their firing rate-based tuning. The across day stability correlated with tuning reliability. Notably, temporal codes increased single neuron tuning stability, especially for less reliable neurons. Temporal coding further improved population representation discriminability and decoding accuracy. The stability of temporal codes was more correlated with network functional connectivity than rate coding. Thus, temporal coding may be essential in ensuring consistent sensory experiences over time. Whether temporal code and rate code have different rates of representational drift over extended periods is not fully understood. Using ultraflexible electrodes, here authors show that temporal codes extracted from fast spiking patterns reduce visual representational drift compared to firing rates over 15 consecutive days in mice.

Land plants alternate between generations of asexual sporophytes and sexual gametophytes. Unlike seed plants, ferns produce free-living gametophytes that grow independently from their sporophytes. Gametophytes of the model fern Ceratopteris exist in two sex types: hermaphrodites and males. Hermaphrodites maintain meristems and secrete the pheromone antheridiogen, inducing undecided gametophytes to become males. In the absence of antheridiogen, males exhibit developmental plasticity and dynamic cell fate specification by initiating de novo meristems to convert into hermaphrodites. Despite its essential role, the molecular signals governing this process remain unclear. Here, we show that local auxin biosynthesis, dynamically regulated during sex-type conversion, establishes new auxin maxima that are critical for specifying and promoting the proliferation of the meristem progenitor cell (MPC) lineage, ultimately enabling the de novo formation of a multicellular meristem from a single MPC. Time-lapse imaging revealed that upon antheridiogen removal, auxin signaling is specifically activated at the initial site of proliferation in Ceratopteris males, triggering new meristem formation. This auxin signaling subsequently becomes concentrated at the center of the proliferating meristem, aligning with localized auxin biosynthesis and the emergence of the meristem notch. Computationally reconstrued lineage maps further showed that chemical inhibition of CrTAA1 abolishes these dynamic auxin patterns, blocking MPC lineage initiation and its subsequent proliferation. Furthermore, genetic knockout of CrTAA1 via CRISPR-Cas9 phenocopies the effects of chemical inhibition, preventing new meristem formation and disrupting male-to-hermaphrodite conversion. Together, these findings uncover a molecular mechanism underlying sex-type conversion in land plants and highlight the pivotal role of de novo auxin biosynthesis in orchestrating cell fate and proliferation during meristem formation.