Abstract To emulate the ordered arrangement of monomer units found in natural macromolecules, single-unit monomer insertion (SUMI) have emerged as a potent technique for synthesizing ...sequence-controlled vinyl polymers. Specifically, numerous applications necessitate vinyl polymers encompassing both radically and cationically polymerizable monomers, posing a formidable challenge due to the distinct thiocarbonylthio end-groups required for efficient control over radical and cationic SUMIs. Herein, we present a breakthrough in the form of interconvertible radical and cationic SUMIs achieved through the manipulation of thiocarbonylthio end-groups. The transition from a trithiocarbonate (for radical SUMI) to a dithiocarbamate (for cationic SUMI) is successfully accomplished via a radical-promoted reaction with bis(thiocarbonyl) disulfide. Conversely, the reverse transformation utilizes the reaction between dithiocarbamate and bistrithiocarbonate disulfide under a cationic mechanism. Employing this strategy, we demonstrate a series of synthetic examples featuring discrete oligomers containing acrylate, maleimide, vinyl ether, and styrene, compositions unattainable through the SUMI of a single mechanism alone.
Using the rock testing system, MTS-815, we conducted cyclic-confinement loading tests on the joints, made of Maokou Limestone. Then, by analyzing the characteristics of the confinement-normal ...displacement curve of the joints with various roughness coefficients, initial openings and confinements, we investigated the energy dissipation law of the plastic hysteresis loop, the elastic–plastic law and the stiffness characteristics of the joints. The results show that the increase in the confinement cycle shrunk the area of the plastic hysteresis loop; whereas the increase in the roughness of the joint surfaces enlarged the area, and further promoted the dissipated energy. In addition, plastic deformation and elastic deformation subsequently occurred on the joint with the increase in the confinement cycle. Moreover, the increase in the confinement cycle promoted the normal stiffness. According to the characteristics of the normal deformation, an index, β, was introduced to modify the power function model for the normal stiffness of the joint after specific loading cycles. The fitted curves, obtained from the modified model, agree well with the laboratory curves.
An important challenge for phototherapy is spatiotemporal controlling of its efficiency while reducing side effects and improving efficacy. Here, we show how to overcome this challenge by ...autocatalytic photodynamic amplification of protoporphyrin IX moieties (PpIX)-conjugated pH-responsive shell cross-linked (SCL) micelles with a 1O2-cleavable cross-linker. At a neutral pH, self-quenching among photosensitizers and photoinduced electron transfer (PET) process between PpIX and pH-responsive polymers results in low fluorescence emission and 1O2 generation capacity. The protonation of core-formed poly(2-diisopropylaminoethyl methacrylate) (PDPA) blocks triggers partially enhanced emission of PpIX and photodynamic rate at the weakly acidic pH associated with endosomes. More importantly, 1O2 generated by the red-light irradiation breaks the cross-linker and weakens the self-quenching, which further enhances the fluorescence emission and photodynamic efficiency. This self-amplification process simultaneously drives photodynamic therapy, drug release, and endosomal escape.
Northeast China is the leading grain production region in China where one-fifth of the national grain is produced; however, consistent and reliable crop maps are still unavailable, impeding crop ...management decisions for regional and national food security. Here, we produced annual 10-m crop maps of the major crops (maize, soybean, and rice) in Northeast China from 2017 to 2019, by using (1) a hierarchical mapping strategy (cropland mapping followed by crop classification), (2) agro-climate zone-specific random forest classifiers, (3) interpolated and smoothed 10-day Sentinel-2 time series data, and (4) optimized features from spectral, temporal, and texture characteristics of the land surface. The resultant maps have high overall accuracies (OA) spanning from 0.81 to 0.86 based on abundant ground truth data. The satellite estimates agreed well with the statistical data for most of the municipalities (R
≥ 0.83, p < 0.01). This is the first effort on regional annual crop mapping in China at the 10-m resolution, which permits assessing the performance of the soybean rejuvenation plan and crop rotation practice in China.
Next-generation polarized mid-infrared imaging systems generally requires miniaturization, integration, flexibility, good workability at room temperature and in severe environments, etc. Emerging ...two-dimensional materials provide another route to meet these demands, due to the ease of integrating on complex structures, their native in-plane anisotropy crystal structure for high polarization photosensitivity, and strong quantum confinement for excellent photodetecting performances at room temperature. However, polarized infrared imaging under scattering based on 2D materials has yet to be realized. Here we report the systematic investigation of polarized infrared imaging for a designed target obscured by scattering media using an anisotropic tellurium photodetector. Broadband sensitive photoresponse is realized at room temperature, with excellent stability without degradation under ambient atmospheric conditions. Significantly, a large anisotropic ratio of tellurium ensures polarized imaging in a scattering environment, with the degree of linear polarization over 0.8, opening up possibilities for developing next-generation polarized mid-infrared imaging technology.
We herein report a fascinating carbon aerogel that has a unique framework structure consisting of one-dimensional (i.e. nanofibers) and two-dimensional (i.e. graphene) carbon nanomaterials. Such a ...carbon aerogel was prepared by carbonization of electrospun polyacrylonitrile with graphene oxide sheets (GO). The nanofiber-graphene interconnection within the aerogel considerably enhances the electrochemical characteristics. The aerogel showed an electrosorption capacity of 15.7 mg g−1 in 500 mg L−1 NaCl solution, and the CDI cell exhibited stable performance over 100 cycles. Moreover, the carbon aerogel has good electrical conductivity and faster electron transfer rate. Such a cross-linked porous aerogel may provide a new strategy for highly efficient CDI applications.
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•A fascinating carbon aerogel with 3D layered porous structure is fabricated via electrospinning, freeze-shaping and carbonization.•Novel structures and electrochemical properties of the electrodes are tested.•The obtained carbon aerogel has good electrical conductivity and faster electron transfer rate.•The obtained carbon aerogel exhibits extraordinary electrochemical characteristics and a high electrosorption capacity.
Subjective tinnitus, the perception of sound without an external acoustic source, is often subsequent to noise-induced hearing loss or ototoxic medications. The condition is believed to result from ...neuroplastic alterations in the auditory centers, characterized by heightened spontaneous neural activities and increased synchrony due to an imbalance between excitation and inhibition. However, the role of the thalamic reticular nucleus (TRN), a structure composed exclusively of GABAergic neurons involved in thalamocortical oscillations, in the pathogenesis of tinnitus remains largely unexplored.
We induced tinnitus in mice using sodium salicylate and assessed tinnitus-like behaviors using the Gap Pre-Pulse Inhibition of the Acoustic Startle (GPIAS) paradigm. We utilized combined viral tracing techniques to identify the neural circuitry involved and employed immunofluorescence and confocal imaging to determine cell types and activated neurons.
Salicylate-treated mice exhibited tinnitus-like behaviors. Our tracing clearly delineated the inputs and outputs of the auditory-specific TRN. We discovered that chemogenetic activation of the auditory TRN significantly reduced the salicylate-evoked rise in c-Fos expression in the auditory cortex.
This finding posits the TRN as a potential modulatory target for tinnitus treatment. Furthermore, the mapped sensory inputs to the auditory TRN suggest possibilities for employing optogenetic or sensory stimulations to manipulate thalamocortical activities. The precise mapping of the auditory TRN-mediated neural pathways offers a promising avenue for designing targeted interventions to alleviate tinnitus symptoms.
Dynamic biological structures involve the continual turnover of molecules within supramolecular assemblies such as tubulin. Inspired by dynamic biology self-organizing systems, we build an artificial ...dynamic structure based on DNA nanotechnology through a nonequilibrium chemical system. Herein, a metastable domain (MD), essentially a stem-loop structure, was introduced into DNA hairpins within hybridization chain reaction (HCR), thereby imparting dynamic activity to the DNA polymers. Hairpins with MD thermodynamically assemble to a high-energy polymer in the presence of trigger strands. The polymer can relax back to the stable unassembled state once the invader is added and finally relax to the activated hairpin by an anti-invader. Reversible assembly/disassembly of the HCR is achieved through invader/anti-invader cycles. We accomplished kinetic modulation, reversible conformational switching, cascading regulation, and enzyme activity control through the MD-HCR. We believe that the design of the MD-HCR could inspire the development of autonomous biological functions within artificial systems.
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•A simple four-step method to prepare T-Nb2O5/CNTs composite.•The composite is with well-dispersed CNTs in the Nb2O5 phase.•The composite has excellent large-current discharge ...property.•The composite has a high energy storage property at high current density.
In this paper, we report a facile template-free method to prepare the T-Nb2O5/CNTs composite. The addition of ammonia induces the electrostatic interaction between functionalized CNTs and niobic acid colloids during hydrothermal process, resulting in CNTs homogeneously distributed in the T-Nb2O5 phase. The obtained T-Nb2O5/CNTs composite shows high rate Li+ storage ability with typical intercalation capacitive behaviour. The presence of well-dispersed CNTs in Nb2O5 can apparently reduce the limitation from diffusion process and increase the high rate charge-discharge capability. From the galvanostatic tests, a capacity of ∼180mAhg−1 at 1Ag−1 and ∼130mAhg−1 at 5Ag−1 is attained.
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