216 research outputs found
Transplantation of a Peripheral Nerve with Neural Stem Cells Plus Lithium Chloride Injection Promote the Recovery of Rat Spinal Cord Injury
Transplantation of neural stem cells (NSCs) holds great potential for the treatment of spinal cord injury (SCI). However, transplanted NSCs poorly survive in the SCI environment. We injected NSCs into tibial nerve and transplanted tibial nerve into a hemisected spinal cord and investigated the effects of lithium chloride (LiCl) on the survival of spinal neurons, axonal regeneration, and functional recovery. Our results show that most of the transplanted NSCs expressed glial fibrillary acidic protein, while there was no obvious expression of nestin, neuronal nuclei, or acetyltransferase found in NSCs. LiCl treatment produced less macrosialin (ED1) expression and axonal degeneration in tibial nerve after NSC injection. Our results also show that a regimen of LiCl treatment promoted NSC differentiation into NF200-positive neurons with neurite extension into the host spinal cord. The combination of tibial nerve transplantation with NSCs and LiCl injection resulted in more host motoneurons surviving in the spinal cord, more regenerated axons in tibial nerve, less glial scar area, and decreased ED1 expression. We conclude that lithium may have therapeutic potential in cell replacement strategies for central nervous system injury due to its ability to promote survival and neuronal generation of grafted NSCs and reduced host immune reaction
Persistent sulfate formation from London Fog to Chinese haze
Sulfate aerosols exert profound impacts on human and ecosystem health, weather, and climate, but their formation mechanism remains uncertain. Atmospheric models consistently underpredict sulfate levels under diverse environmental conditions. From atmospheric measurements in two Chinese megacities and complementary laboratory experiments, we show that the aqueous oxidation of SO2 by NO2 is key to efficient sulfate formation but is only feasible under two atmospheric conditions: on fine aerosols with high relative humidity and NH3 neutralization or under cloud conditions. Under polluted environments, this SO2 oxidation process leads to large sulfate production rates and promotes formation of nitrate and organic matter on aqueous particles, exacerbating severe haze development. Effective haze mitigation is achievable by intervening in the sulfate formation process with enforced NH3 and NO2 control measures. In addition to explaining the polluted episodes currently occurring in China and during the 1952 London Fog, this sulfate production mechanism is widespread, and our results suggest a way to tackle this growing problem in China and much of the developing world
Non-line-of-sight Target Relocation by Multipath Model in SAR 3D Urban Area Imaging
The advancement in the miniaturization technology of Synthetic Aperture Radar (SAR) systems and SAR three-dimensional (3D) imaging has enabled the 3D imaging of urban areas through Unmanned Aerial Vehicle (UAV)-borne array Interferometric SAR (array-InSAR), offering significant utility in urban cartography, complex environment reconstruction, and related domains. Despite the challenges posed by multipath signals in urban scene imaging, these signals serve as a crucial asset for imaging hidden targets in Non-Line-of-Sight (NLOS) areas. Hence, this paper studies NLOS targets in UAV-borne array-InSAR 3D imaging at low altitudes and establishes a multipath model for 3D imaging at low altitudes. Then, a calculation method is proposed for obtaining the multipath reachable range in urban canyon areas based on building plane fitting. Finally, a relocation method for NLOS targets is presented. The simulation and real data experiments of UAV-borne array-InSAR show that the proposed method can effectively obtain 3D images and relocate NLOS targets in urban canyon areas, with errors typically below 0.5 m, which realizes the acquisition of hidden NLOS region information
Metatranscriptomic Signatures Associated With Phytoplankton Regime Shift From Diatom Dominance to a Dinoflagellate Bloom
Diatoms and dinoflagellates dominate coastal marine phytoplankton communities as major players of marine biogeochemical cycles and their seasonal succession often leads to harmful algal blooms (HABs). What regulates their respective dominances and the development of the HABs remains elusive. Here we conducted time-sequential metatranscriptomic profiling on a natural assemblage that evolved from diatom dominance to a dinoflagellate bloom to interrogate the underlying major metabolic and ecological drivers. Data reveals similarity between diatoms and dinoflagellates in exhibiting high capacities of energy production, nutrient acquisition, and stress protection in their respective dominance stages. The diatom-to-dinoflagellate succession coincided with an increase in turbidity and sharp declines in silicate and phosphate availability, concomitant with the transcriptomic shift from expression of silicate uptake and urea utilization genes in diatoms to that of genes for light harvesting, diversified phosphorus acquisition and autophagy-based internal nutrient recycling in dinoflagellates. Furthermore, the diatom-dominant community featured strong potential to carbohydrate metabolism and a strikingly high expression of trypsin potentially promoting frustule building. In contrast, the dinoflagellate bloom featured elevated expression of xanthorhodopsin, and antimicrobial defensin genes, indicating potential importance of energy harnessing and microbial defense in bloom development. This study sheds light on mechanisms potentially governing diatom- and dinoflagellate-dominance and regulating bloom development in the natural environment and raises new questions to be addressed in future studies
Granular Ta-Te nanowire superconductivity violating the Pauli limit
Strategies to achieve higher upper-critical-field superconductors
({\mu}0Hc2(0)) are of great interest for both fundamental science and practical
applications. While reducing the thickness of two-dimensional (2D) materials to
a few layers significantly enhances {\mu}0Hc2(0) with accompanied potential
unconventional pairing mechanisms, further dimensional reduction to 1D
compounds rarely exceeds the expected Pauli limit. Here, we report the
discovery of a 1D granular Ta-Te nanowire that becomes superconducting under
high pressure, with a maximum critical temperature (Tc) of 5.1 K. Remarkably,
the {\mu}0Hc2(0) reaches 16 T, which is twice the Pauli limit, setting a record
of {\mu}0Hc2 (0) in all the reported 1D superconductors. Our work demonstrates
that the Ta-Te nanowire not only is a potential candidate for applications in
high magnetic fields, but also provides an ideal platform for further
investigations of the mechanisms between nanowires and large {\mu}0Hc2(0).Comment: 12 pages,4 figure
Pore Characteristics of the Upper Carboniferous Taiyuan Shale in Liaohe Depression
High pressure mercury, nitrogen adsorption, nano-CT, and scanning electron microscope with energy spectrum analysis were conducted on core shale samples for studying the characteristics of Taiyuan formation in the eastern uplift of Liaohe depression. The research results show that the shale gas reservoir pores are mainly open pores such as the wedge-shape pores and parallel-plate pores. By a genetic type, pores mainly include organic pore, pyrite crystal particle pore, illite intragranular pore, illite-smectite mixed layer intragranular pore, and feldspar dissolved pore. The micropore and mesopore play an important role in shale gas reservoir, and their surface area and pore volume are 9.56 m2/g, 0.0414 mL/g, 97.3%, and 68.8% respectively. The pores diameter presents a bimodal distribution with two main peaks at 43 nm and 6.35 μm. Based on the nano-CT, the porosity is 4.36% and the permeability is 204 nD. The brittle minerals played a supportive and protective role for the pores and controlled their spatial distribution
Disorder-broadened phase boundary with enhanced amorphous superconductivity in pressurized In2Te5
As an empirical tool in materials science and engineering, the iconic phase
diagram owes its robustness and practicality to the topological characteristics
rooted in the celebrated Gibbs phase law (F = C - P + 2). When crossing the
phase diagram boundary, the structure transition occurs abruptly, bringing
about an instantaneous change in physical properties and limited
controllability on the boundaries (F = 1). Here, we expand the sharp phase
boundary to an amorphous transition region (F = 2) by partially disrupting the
long-range translational symmetry, leading to a sequential
crystalline-amorphous-crystalline (CAC) transition in a pressurized In2Te5
single crystal. Through detailed in-situ synchrotron diffraction, we elucidate
that the phase transition stems from the rotation of immobile blocks
[In2Te2]2+, linked by hinge-like [Te3]2- trimers. Remarkably, within the
amorphous region, the amorphous phase demonstrates a notable 25 % increase of
the superconducting transition temperature (Tc), while the carrier
concentration remains relatively constant. Furthermore, we propose a
theoretical framework revealing that the unconventional boost in amorphous
superconductivity might be attributed to an intensified electron correlation,
triggered by a disorder-augmented multifractal behavior. These findings
underscore the potential of disorder and prompt further exploration of
unforeseen phenomena on the phase boundaries.Comment: 14 pages, 4 figures, Accepted for publication in Advanced Material
Metabolic and transcriptomic responses of Taxus mairei to nano-pollutants: insights into AgNPs and PsNPs impact
There is a growing global concern regarding the pervasive issue of nano-pollutants. Typical nano-materials, such as polystyrene nanoplastics (PsNPs) and silver nanoparticles (AgNPs), pose significant risks to ecosystems and human health. Taxus mairei is a well-known gymnosperm widely planted in South China and has great medicinal qualities. However, the effects of nano pollutants on the primary and secondary metabolism of Taxus plants have not been sufficiently explored. We investigated the responses of T. mairei to different nano-pollutants via physiological, transcriptomic, and metabolomic analyses. AgNPs and PsNPs significantly affected several secondary and energy metabolism-related pathways, respectively. In T. mairei, AgNPs greatly impacted flavonoid metabolism by regulating the expression of the CHI gene, while PsNPs significantly impacted energy metabolism by regulating the expression of FRK genes. Furthermore, a transcriptional regulation network, including GATA (ctg10916_gene.2), bHLH (ctg495_gene.7), MYB (ctg18368_gene.1), and NAC (ctg8193_gene.1), was predicted to be associated with the responses of T. mairei to nano-pollutants. The present study elucidated a regulatory mechanism underlying the responses of T. mairei to nano-pollutants, which has the potential to aid in the breeding of Taxus species with high environmental adaptability
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