Carbon nanotubes (CNTs) and their related hybrids grown by chemical vapor deposition (CVD) method have been frequently used as energy-storage electrode materials. In most cases, the tips of CNTs are ...almost well closed, which often limits the utilization efficiency of their tubular structure in storage of charges. In this work, the authors have designed a type of tip-open CNT/CNF hierarchical hybrids via KOH activation on the CVD-grown Al/Fe-catalyzed CNT/CNF precursors. Results showed that the CNT hierarchies' tips can be fully opened via KOH activation at 700–750 °C for 90 min. As expected, the tip-open CNT-CNF hybrids show a highly improved specific capacitance, which increases by 3.3 times that of the pristine ones. Moreover, sweep analysis indicated that the diffusion-type capacitance increases by 3.7 times while the Helmholtz-type capacitance increases only by 1.5 times, indicating that the tip-open CNTs contribute to ∼30% of the increase in double-layer capacitance. Further optimization on activation time and temperature indicated that activation at 700 °C for 90 min is suitable for opening the tips of CNT hierarchies and protecting the CNTs’ tubular structure. This research would give some useful advice for the preparation of high-performance CNT-related electrode materials for energy storage.
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Recent advances in perovskite ferroelectrics have fostered a host of exciting sensors and actuators. Defect engineering provides critical control of the performance of ferroelectric materials, ...especially lead‐free ones. However, it remains a challenge to quantitatively study the concentration of defects due to the complexity of measurement techniques. Here, a feasible approach to analyzing the A‐site defect and electron in alkali metal niobate is demonstrated. The theoretical relationships among defect concentration, conductivity, and oxygen partial pressure can be established based on the defect chemistry equilibria. The type and concentration of defects are reflected through the conductivity variation with oxygen partial pressure. As a result, the variation of defect concentration gives rise to defect‐driven interfacial polarization, which further leads to distinct properties of the ceramics. e.g., abnormal dielectric behavior. Furthermore, this study also suggests a strategy to manipulate defects and charges in perovskite oxides for performance optimization.
For perovskites, it is challenging to quantitatively study the concentration of defects. A theoretical relationship between defect concentration, conductivity, and oxygen partial pressure can be established based on the defect chemistry equilibria. The type and concentration of defects are reflected through the conductivity variation with oxygen partial pressure.
Transient receptor potential (TRP) channels, subdivided into 6 subfamilies in mammals, have essential roles in sensory physiology. They respond to remarkably diverse stimuli, comprising thermal, ...chemical, and mechanical modalities, through opening or closing of channel gates. In this study, we systematically substituted the hydrophobic residues within the distal fragment of pore‐lining helix S6 with hydrophilic residues and, based on Xenopus oocyte and mammalian cell electrophysiology and a hydrophobic gate theory, identified hydrophobic gates in TRPV6/V5/V4/C4/ M8. We found that channel activity drastically increased when TRPV6Ala616 or Met617 or TRPV5Ala576 or Met577, but not any of their adjacent residues, was substituted with hydrophilic residues. Channel activity strongly correlated with the hydrophilicity of the residues at those sites, suggesting that consecutive hydrophobic residues TRPV6Ala616‐Met617 and TRPV5Ala576‐Met577 form a double‐residue gate in each channel. By the same strategy, we identified a hydrophobic single‐residue gate in TRPV4Iso715, TRPC4Iso617, and TRPM8Val976. In support of the hydrophobic gate theory, hydrophilic substitution at the gate site, which removes the hydrophobic gate seal, substantially increased the activity of TRP channels in low‐activity states but had little effect on the function of activated channels. The double‐residue gate channels were more sensitive to small changes in the gate's hydrophobicity or size than single‐residue gate channels. The unconventional double‐reside gating mechanism in TRP channels may have been evolved to respond especially to physiologic stimuli that trigger relatively small gate conformational changes.—Zheng, W., Hu, R., Cai, R., Hofmann, L., Hu, Q., Fatehi, M., Long, W., Kong, T., Tang, J., Light, P., Flockerzi, V., Cao, Y., Chen, X.‐Z. Identification and characterization of hydrophobic gate residues in TRP channels. FASEB J. 32, 639–653 (2018). www.fasebj.org
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•Low-cost PP fibers are hybridized with PE fibers to reduce the cost of PE-EGC.•The tensile behaviors and mechanical properties of PP/PE-EGC are investigated.•A tensile stress–strain ...model is proposed based on the cracking characteristics.•The economic performance of PP/PE-EGC are investigated.
Engineering geopolymer composites (EGC) are a promising low-carbon and highly durable composite material. However, the high cost of materials hinders its engineering application. To address this challenge, this study investigates the use of cost-effective PP fibers to partially or completely replace PE fibers, and develops an economical hybrid PE/PP-EGC. Axial tensile experiments were conducted on PE/PP-EGC with different PP fiber replacement ratios (0%, 25%, 50%, 75%, and 100%) to investigate the effect of PP fiber replacement ratios on the tensile behaviour of PE/PP-EGC. Economic feasibility of PE/PP-EGC is also evaluated. The results show that when the replacement ratio is below 75%, PE/PP-EGC still exhibits pseudo-strain hardening and multiple cracking characteristics. As the replacement ratio increases, the crack control ability of EGC decreases, resulting in an increase in the average crack width and a decrease in the crack density. PE/PP-EGC with a replacement ratio of 50% has a highest ultimate tensile strain (9.71%), which is 68% higher than that of PE-EGC, while the tensile strength is only reduced by 15%. Furthermore, PE/PP-EGC with a replacement ratio of 50% exhibits the highest tensile strength, ultimate tensile strain, and tensile strain energy per unit cost. Based on the experimental data and theoretical derivation, this study proposes a semi-empirical bilinear tensile constitutive model of PE/PP-EGC and verifies its reliability. It is recommended to use a 50% replacement ratio of PP fibers for PE/PP-EGC, which offers optimal tensile mechanical performance, along with outstanding comprehensive economical performance. These research findings provide important insights into the design and application of low-cost and high-performance engineering geopolymer composites, and could have significant implications for the development of sustainable and durable infrastructure.
The Lg-wave spectra are investigated for the 2019 Changning ML 6.0 earthquake and its 94 aftershocks with magnitudes above ML 2.8, which occurred in the southern Sichuan Basin, Southwest China. This ...earthquake sequence is potentially related to the water injection from nearby salt mining activities. Based on an established regional high-resolution broadband Lg-wave attenuation model, we correct the observed spectra for the attenuation effect along the propagation path. By fitting the observed spectra from the Changning earthquake sequence with the theoretical source model, we estimate seismic moments and corner frequencies, from which the stress drops are calculated for the entire earthquake sequence. The results show that the stress drops are rather scattered, ranging from 0.16 MPa to 32 MPa with a median value of 0.78 MPa. Spatiotemporal variation of stress drops reflects strong fault heterogeneity and a complex stress release process, which is likely influenced by water injection and diffusion. Positive trends are observed between the stress drop and focal depth and between the stress drop and seismic magnitude. Relatively lower stress drops for most shallow events are possibly the indication of lowered normal stress by long-term fluid injection. No apparent relation is observed between the stress drop and the distance to the Shuanghe salt mine, where water was injected. Combining the actual water injection data and previous numerical simulation studies, we suggest that the salt mining-related water injection may lead to elevated pore pressure beyond the source region of the 2019 Changning earthquake. The increasingly cumulated underground water may have created pathways linking multiple fault systems, thus the possibility of future large induced-earthquakes cannot be ruled out.
•The Lg-wave source spectra are revised for the 2019 Changning earthquake sequence.•Stress drops are obtained by fitting source spectra based on the Brune's source model.•The lowered normal stress by long-term injection may lower the stress drops of most shallow events.
Alzheimer's disease (AD) is currently ranked as the third leading cause of death for eldly people, just behind heart disease and cancer. Autophagy is declined with aging. Our study determined the ...biphasic changes of miR-331-3p and miR-9-5p associated with AD progression in APPswe/PS1dE9 mouse model and demonstrated inhibiting miR-331-3p and miR-9-5p treatment prevented AD progression by promoting the autophagic clearance of amyloid beta (Aβ).
The biphasic changes of microRNAs were obtained from RNA-seq data and verified by qRT-PCR in early-stage (6 months) and late-stage (12 months) APPswe/PS1dE9 mice (hereinafter referred to as AD mice). The AD progression was determined by analyzing Aβ levels, neuron numbers (MAP2
) and activated microglia (CD68
IBA1
) in brain tissues using immunohistological and immunofluorescent staining. MRNA and protein levels of autophagic-associated genes (
) were tested to determine the autophagic activity. Morris water maze and object location test were employed to evaluate the memory and learning after antagomirs treatments in AD mice and the Aβ in the brain tissues were determined.
MiR-331-3p and miR-9-5p are down-regulated in early-stage of AD mice, whereas up-regulated in late-stage of AD mice. We demonstrated that miR-331-3p and miR-9-5p target autophagy receptors Sequestosome 1 (
) and Optineurin (
), respectively. Overexpression of miR-331-3p and miR-9-5p in SH-SY5Y cell line impaired autophagic activity and promoted amyloid plaques formation. Moreover, AD mice had enhanced Aβ clearance, improved cognition and mobility when treated with miR-331-3p and miR-9-5p antagomirs at late-stage.
Our study suggests that using miR-331-3p and miR-9-5p, along with autophagic activity and amyloid plaques may distinguish early versus late stage of AD for more accurate and timely diagnosis. Additionally, we further provide a possible new therapeutic strategy for AD patients by inhibiting miR-331-3p and miR-9-5p and enhancing autophagy.
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•Controlled and rapid synthesis of stearic and lauric acid-based block copolymers with thermoresponsive PNVCL segment in 30 min.•Tunable self-assembly of the polymeric micelles into ...different morphologies and particle sizes.•The micelles exhibited high DOX loading capacity and controlled DOX release.•The micelles showed favorable serum stability, excellent biocompatibility and temperature-responsive properties.•The drug-loaded micelles demonstrated effective in vitro anti-tumor activity and efficient cellular uptake.
Lipids, as naturally occurring biomolecules have emerged as promising carriers for delivering various therapeutic agents. However, only a few attempts have been made in terms of their applications as amphiphilic block copolymers for anticancer drug delivery. In this work, a biocompatible micellar drug delivery system with fatty acid-based polymer core and temperature-sensitive shell was developed. A series of amphiphilic block copolymers poly(vinyl stearate)/poly(vinyl laurate)-b-poly(N-vinylcaprolactam) (PVS/PVL-b-PNVCL) were synthesized via microwave-assisted reversible addition-fragmentation chain transfer polymerization in a controlled fashion. By varying the fatty acid type and hydrophilic/hydrophobic block lengths, the self-assembly behaviour of the block copolymer micelles proved to be highly tunable in terms of their morphology and particle size. Nile Red and hydrophobic anticancer drug doxorubicin (DOX) were effectively incorporated into the micelles, demonstrating high drug loading capacity, good serum stability, and temperature-dependent drug release characteristics of the polymeric micelles. In vitro studies using cell models revealed that blank PVS -b-PNVCL micelles are biocompatible with different cell lines, while DOX-loaded micelles were internalized into and accumulated in the cells, showing a high cytotoxic effect against HeLa cells. These findings suggest an opportunity for the development of safe and efficient lipid-based micellar system for smart drug delivery and cancer treatments.
Increasing evidence indicates that FK866, a specific noncompetitive nicotinamide phosphoribosyl transferase inhibitor, exhibits a protective effect on acute lung injury (ALI). Autophagy plays a ...pivotal role in sepsis-induced ALI. However, the contribution of autophagy and the underlying mechanism by which FK866-confered lung protection remains elusive. Herein, we aimed to study whether FK866 could alleviate sepsis-induced ALI via the JNK-dependent autophagy.
Male C57BL/6 mice were subjected to cecal ligation and puncture (CLP) to establish the polymicrobial sepsis mice model, and treated with FK866 (10 mg/kg) at 24, 12 and 0.5 h before the CLP procedure. The lung protective effects were measured by lung histopathology, tissue edema, vascular leakage, inflammation infiltration, autophagy-related protein expression and JNK activity. A549 cells were stimulated with LPS (1000 ng/ml) to generate the ALI cell model, and pretreated with FK866 or SP600125 for 30 min to measure the autophagy-related protein expression and JNK activity.
Our results demonstrated that FK866 reduced lung injury score, tissue edema, vascular leakage, and inflammatory infiltration, and upregulated autophagy. The protective effect of autophagy conferred by FK866 on ALI was further clarified by using 3-methyladenine (3MA) and rapamycin. Additionally, the activity of JNK was suppressed by FK866, and inhibition of JNK promoted autophagy and showed a benefit effect.
Our study indicates that FK866 protects against sepsis-induced ALI by induction of JNK-dependent autophagy. This may provide new insights into the functional mechanism of NAMPT inhibition in sepsis-induced ALI.
•Levels of NAMPT expression were increased in a sepsis-related ALI mice model.•NAMPT inhibitor FK866 attenuated sepsis-induced ALI by upregulating autophagy.•JNK was a potent negative regulator of autophagy conferred by FK866 on lung protection.
Osteoporosis is one of the most common metabolic bone diseases affecting millions of people. We previously found that harmine prevents bone loss in ovariectomized mice via increasing preosteoclast ...platelet‐derived growth factor‐BB (PDGF‐BB) production and type H vessel formation. However, the molecular mechanisms by which harmine promotes preosteoclast PDGF‐BB generation are still unclear. In this study, we revealed that inhibitor of DNA binding‐2 (Id2) and activator protein‐1 (AP‐1) were important factors implicated in harmine‐enhanced preosteoclast PDGF‐BB production. Exposure of RANKL‐induced Primary bone marrow macrophages (BMMs), isolated from tibiae and femora of mice, to harmine increased the protein levels of Id2 and AP‐1. Knockdown of Id2 by Id2‐siRNA reduced the number of preosteoclasts as well as secretion of PDGF‐BB in RANKL‐stimulated BMMs administrated with harmine. Inhibition of c‐Fos or c‐Jun (components of AP‐1) both reversed the stimulatory effect of harmine on preosteoclast PDGF‐BB production. Dual‐luciferase reporter assay analyses determined that PDGF‐BB was the direct target of AP‐1 which was up‐regulated by harmine treatment. In conclusion, our data demonstrated a novel mechanism involving in the production of PDGF‐BB increased by harmine, which may provide potential therapeutic targets for bone loss diseases.
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