11 research outputs found
Aberrant Brain Regional Homogeneity and Functional Connectivity of Entorhinal Cortex in Vascular Mild Cognitive Impairment: A Resting-State Functional MRI Study
The aim of this study was to investigate changes in regional homogeneity (ReHo) and the functional connectivity of the entorhinal cortex (EC) in vascular mild cognitive impairment (VaMCI) and to evaluate the relationships between such changes and neuropsychological measures in VaMCI individuals. In all, 31 patients with VaMCI and 32 normal controls (NCs) underwent rs-fMRI. Differences in whole-brain ReHo and seed-based bilateral EC functional connectivity (EC-FC) were determined. Pearson's correlation was used to evaluate the relationships between regions with significant group differences and different neuropsychological measures. Vascular mild cognitive impairment (VaMCI) patients had lower scores in Mini-mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) and higher ones in Activity of Daily Living (ADL) (p < 0.05). Vascular mild cognitive impairment (VaMCI) individuals had significantly lower ReHo in the left cerebellum and right lentiform nucleus than NCs (P < 0.05, TFCE FWE correction). Vascular mild cognitive impairment (VaMCI) subjects showed significant decreases in the FC of the right EC in the right inferior frontal gyrus, right middle frontal gyrus, bilateral pre-central gyrus, and right post-central/superior parietal lobules (P < 0.05, TFCE FWE correction). Significant positive correlations were found between ReHo and MoCA scores for the right lentiform nucleus (r = 0.37, P < 0.05). The right post-central/superior parietal lobules showed a significant positive correlation between right EC-FC and MoCA scores (r = 0.37, P < 0.05). Patterns in ReHo and EC-FC changes in VaMCI patients and their correlations with neuropsychological measures may be a pathophysiological foundation of cognitive impairment, which may aid the early diagnosis of VaMCI
Epoxy Resin Enables Facile Scalable Synthesis of CuO/C Nanohybrid Lithium-Ion Battery Anode with Enhanced Electrochemical Performance
CuO based anodes hold a promise alternative to the commercial graphite due to their high reversible capacities, low cost, and environmental friendliness. However, drastic volume change, partial irreversibility, and poor electron conductivity yields compromised the electrochemical performance including reversible capacities, cyclic stability and rate performance. A facile scalable method is developed to synthesize CuO/C nanohybrid lithium-ion battery anode. Copper nanoparticles are synthesized in situ using the amine based curing agent as both coordination ligand and reducing agent. The copper nanoparticles/amine based curing agent further reacts with the epoxy resin monomers, where the copper nanoparticles are incorporated into the thermosetting polymer network. Due to thermosetting nature of the epoxy polymer, agglomeration of the copper nanoparticles is effectively suppressed during the carbonization process, which are further converted to the CuO nanoparticles within the carbon matrix through heat treatment in air. Systematic structure and electrochemical performance characterizations are carefully studied. The results show that both the reversible capacities are effectively improved in comparision with the bare carbon sample. Moreover, excellent cyclic stability and high rate capability are also demonstrated by the CuO/C nanohybrid
Self-Templating Construction of 3D Hierarchical Macro-/Mesoporous Silicon from OD Silica Nanoparticles
Porous silicon has found wide applications in many different fields including catalysis and lithium-ion batteries. Three-dimensional hierarchical macro-/mesoporous silicon is synthesized from zero-dimensional Stober silica particles through a facile and scalable magnesiothermic reduction process. By systematic structure characterization of the macro-/mesoporous silicon, a self-templating mechanism governing the formation of the porous silicon is proposed. Applications as lithium-ion battery anode and photocatalytic hydrogen evolution catalyst are demonstrated. It is found that the macro-/mesoporous silicon shows significantly improved cyclic and rate performance over the commercial nanosized and micrometer-sized silicon particles. After 300 cycles at 0.2 A g(-1), the reversible specific capacity is still retained as much as 959 mAh g(-1) with a high mass loading density of 1.4 mg cm(-2). With the large current density of 2 A g(-1), a reversible capacity of 632 mAh g(-1) is exhibited. The coexistence of both macro- and mesoporous structures is responsible for the enhanced performance. The macro-/mesoporous silicon also shows superior catalytic performance for photocatalytic hydrogen evolution compared to the silicon nanoparticles
Silicon/carbon lithium-ion battery anode with 3D hierarchical macro-/mesoporous silicon network: Self-templating synthesis via magnesiothermic reduction of silica/carbon composite
Silicon/carbon lithium-ion battery anode with 3D hierarchical macro-/mesoporous silicon network: Self-templating synthesis via magnesiothermic reduction of silica/carbon composit
Exosomes derived from microglia overexpressing miR-124-3p alleviate neuronal endoplasmic reticulum stress damage after repetitive mild traumatic brain injury
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We previously reported that miR-124-3p is markedly upregulated in microglia-derived exosomes following repetitive mild traumatic brain injury. However, its impact on neuronal endoplasmic reticulum stress following repetitive mild traumatic brain injury remains unclear. In this study, we first used an HT22 scratch injury model to mimic traumatic brain injury, then co-cultured the HT22 cells with BV2 microglia expressing high levels of miR-124-3p. We found that exosomes containing high levels of miR-124-3p attenuated apoptosis and endoplasmic reticulum stress. Furthermore, luciferase reporter assay analysis confirmed that miR-124-3p bound specifically to the endoplasmic reticulum stress-related protein IRE1α, while an IRE1α functional salvage experiment confirmed that miR-124-3p targeted IRE1α and reduced its expression, thereby inhibiting endoplasmic reticulum stress in injured neurons. Finally, we delivered microglia-derived exosomes containing miR-124-3p intranasally to a mouse model of repetitive mild traumatic brain injury and found that endoplasmic reticulum stress and apoptosis levels in hippocampal neurons were significantly reduced. These findings suggest that, after repetitive mild traumatic brain injury, miR-124-3 can be transferred from microglia-derived exosomes to injured neurons, where it exerts a neuroprotective effect by inhibiting endoplasmic reticulum stress. Therefore, microglia-derived exosomes containing miR-124-3p may represent a novel therapeutic strategy for repetitive mild traumatic brain injury
Scalable in Situ Synthesis of Li4Ti5O12/Carbon Nanohybrid with Supersmall Li4Ti5O12 Nanoparticles Homogeneously Embedded in Carbon Matrix
Li4Ti5O12 (LTO) is regarded as a promising lithium-ion battery anode due to its stable cyclic performance and reliable operation safety. The moderate rate performance originated from the poor intrinsic electron and lithium-ion conductivities of the LTO has significantly limited its wide applications. A facile scalable synthesis of hierarchical Li4Ti5O12/C nanohybrids with supersmall LTO nanoparticles (ca. 17 nm in diameter) homogeneously embedded in the continuous submicrometer-sized carbon matrix is developed. Difunctional methacrylate monomers are used as solvent and carbon source to generate TiO2/C nanohybrid, which is in situ converted to LTO/C via a solid-state reaction procedure. The structure, morphology, crystallinity, composition, tap density, and electrochemical performance of the LTO/C nanohybrid are systematically investigated. Comparing to the control sample of the commercial LTO composited with carbon, the reversible specific capacity after 1000 cycles at 175 mA g(-1) and rate performance at high current densities (875, 1750, and 3500 mA g(-1)) of the Li4Ti5O12/C nanohybrid have been significantly improved. The enhanced electrochemical performance is due to the unique structure feature, where the supersmall LTO nanoparticles are homogeneously embedded in the continuous carbon matrix. Good tap density is also achieved with the LTO/C nanohybrid due to its hierarchical micro-/nanohybrid structure, which is even higher than that of the commercial LTO powder
SOSTDC1-producing follicular helper T cells promote regulatory follicular T cell differentiation.
Germinal center (GC) responses potentiate the generation of follicular regulatory T (TFR) cells. However, the molecular cues driving TFR cell formation remain unknown. Here, we show that sclerostin domain-containing protein 1 (SOSTDC1), secreted by a subpopulation of follicular helper T (TFH) cells and T-B cell border-enriched fibroblastic reticular cells, is developmentally required for TFR cell generation. Fate tracking and transcriptome assessment in reporter mice establishes SOSTDC1-expressing TFH cells as a distinct T cell population that develops after SOSTDC1- TFH cells and loses the ability to help B cells for antibody production. Notably, Sostdc1 ablation in TFH cells results in substantially reduced TFR cell numbers and consequently elevated GC responses. Mechanistically, SOSTDC1 blocks the WNT-β-catenin axis and facilitates TFR cell differentiation
Si/Ag/C Nanohybrids with in Situ Incorporation of Super-Small Silver Nanoparticles: Tiny Amount, Huge Impact
Silicon (Si) has been regarded as one of the most promising anodes for next-generation lithium-ion batteries (LIBs) due to its exceptional capacity, appropriate voltage profile, and reliable operation safety. However, poor cyclic stability and moderate rate performance have been critical drawbacks to hamper the practical application of Si-based anodes. It has been one of the central issues to develop new strategies to improve the cyclic and rate performance of the Si-based lithium-ion battery anodes. In this work, super-small metal nanoparticles (2.9 nm in diameter) are in situ synthesized and homogeneously embedded in the in situ formed nitrogen-doped carbon matrix, as demonstrated by the Si/Ag/C nanohybrid, where epoxy resin monomers are used as solvent and carbon source. With tiny amount of silver (2.59% by mass), the Si/Ag/C nanohybrid exhibits superior rate performance compared to the bare Si/C sample. Systematic structure characterization and electrochemical performance tests of the Si/Ag/C nanohybrids have been performed. The mechanism for the enhanced rate performance is investigated and elaborated. The temperature-dependent I-V behavior of the Si/Ag/C nanohybrids with tuned silver contents is measured. Based on the model, it is found that the super-small silver nanoparticles mainly increase charge carrier mobility instead of the charge carrier density in the Si/Ag/C nanohybrids. The evaluation of the total electron transportation length provided by the silver nanoparticles within the electrode also suggests significantly enhanced charge carrier mobility. The existence of tremendous amounts of super-small silver nanoparticles with excellent mechanical properties also contributes to the slightly improved cyclic stability compared to that of simple Si/C anodes
Si/Ag/C Nanohybrids with <i>in Situ</i> Incorporation of Super-Small Silver Nanoparticles: Tiny Amount, Huge Impact
Silicon (Si) has been regarded as
one of the most promising anodes for next-generation lithium-ion batteries
(LIBs) due to its exceptional capacity, appropriate voltage profile,
and reliable operation safety. However, poor cyclic stability and
moderate rate performance have been critical drawbacks to hamper the
practical application of Si-based anodes. It has been one of the central
issues to develop new strategies to improve the cyclic and rate performance
of the Si-based lithium-ion battery anodes. In this work, super-small
metal nanoparticles (2.9 nm in diameter) are <i>in situ</i> synthesized and homogeneously embedded in the <i>in situ</i> formed nitrogen-doped carbon matrix, as demonstrated by the Si/Ag/C
nanohybrid, where epoxy resin monomers are used as solvent and carbon
source. With tiny amount of silver (2.59% by mass), the Si/Ag/C nanohybrid
exhibits superior rate performance compared to the bare Si/C sample.
Systematic structure characterization and electrochemical performance
tests of the Si/Ag/C nanohybrids have been performed. The mechanism
for the enhanced rate performance is investigated and elaborated.
The temperature-dependent <i>I–V</i> behavior of
the Si/Ag/C nanohybrids with tuned silver contents is measured. Based
on the model, it is found that the super-small silver nanoparticles mainly increase charge carrier mobility instead of the charge carrier density in the Si/Ag/C nanohybrids. The evaluation of the total electron transportation length provided by the silver nanoparticles within the electrode also suggests significantly enhanced charge carrier mobility. The existence of tremendous amounts of super-small silver nanoparticles with excellent mechanical properties also contributes to the slightly improved cyclic stability compared to that of simple Si/C anodes