21 research outputs found
Differentiation in stem and leaf traits among sympatric lianas, scandent shrubs and trees in a subalpine cold temperate forest
The scandent shrub plant form is a variant of liana that has upright and self-supporting stems when young but later becomes a climber. We aimed to explore the associations of stem and leaf traits among sympatric lianas, scandent shrubs and trees, and the effects of growth form and leaf habit on variation in stem or leaf traits. We measured 16 functional traits related to stem xylem anatomy, leaf morphology and nutrient stoichiometry in eight liana, eight scandent shrub and 21 tree species co-occurring in a subalpine cold temperate forest at an elevation of 2600–3200 m in Southwest China. Overall, lianas, scandent shrubs and trees were ordered along a fast-slow continuum of stem and leaf functional traits, with some traits overlapping. We found a consistent pattern of lianas > scandent shrubs > trees for hydraulically weighted vessel diameter, maximum vessel diameter and theoretical hydraulic conductivity. Vessel density and sapwood density showed a pattern of lianas = scandent shrubs < trees, and lianas < scandent shrubs = trees, respectively. Lianas had significantly higher specific leaf area and lower carbon concentration than co-occurring trees, with scandent shrubs showing intermediate values that overlapped with lianas and trees. The differentiation among lianas, scandent shrubs and trees was mainly explained by variation in stem traits. Additionally, deciduous lianas were positioned at the fast end of the trait spectrum, and evergreen trees at the slow end of the spectrum. Our results showed for the first time clear differentiation in stem and leaf traits among sympatric liana, scandent shrub and tree species in a subalpine cold temperate forest. This work will contribute to understanding the mechanisms responsible for variation in ecological strategies of different growth forms of woody plants
miR-136-5p Regulates the Inflammatory Response by Targeting the IKKβ/NF-κB/A20 Pathway After Spinal Cord Injury
Background/Aims: miR-136-5p participates in recovery after spinal cord injury (SCI) via an unknown mechanism. We investigated the mechanism underlying the involvement of miR-136-5p in the inflammatory response in a rat model of SCI. Methods: Sprague-Dawley rat astrocytes were cultured in vitro to construct a reporter plasmid. Luciferase assays were used to detect the ability of miR-136-5p to target the IKKβ and A20 genes. Next, recombinant lentiviral vectors were constructed, which either overexpressed miR-136-5p or inhibited its expression. The influence of miR-136-5p overexpression and miR-136-5p silencing on inflammation was observed in vivo in an SCI rat model. The expression of IL-1β, IL-6, TNF-α, IFN-α, and related proteins (A20, IKKβ, and NF-κB) was detected. Results: In vitro studies showed that luciferase activity was significantly activated in the presence of the 3’ untranslated region (UTR) region of the IKKβ gene after stimulation of cells with miR-136-5p. However, luciferase activity was significantly inhibited in the presence of the 3’UTR region of the A20 gene. Thus, miR-136-5p may act directly on the 3’UTR regions of the IKKβ and A20 genes to regulate their expression. miR-136-5p overexpression promoted the production of related cytokines and NF-κB in SCI rats and inhibited the expression of A20 protein. Conclusion: Overexpression of miR-136-5p promotes the generation of IL-1β, IL-6, TNF-α, IFN-α, IKKβ, and NF-κB in SCI rats but inhibits the expression of A20. Under these conditions, inflammatory cell infiltration into the rat spinal cord increases and injury is significantly aggravated. Silencing of miR-136-5p significantly reduces the protein expression results described after miR-136-5p overexpression and ameliorates the inflammatory cell infiltration and damage to the spinal cord. Therefore, miR-136-5p might be a new target for the treatment of SCI
人乳头瘤病毒衣壳蛋白C末端结构臂具有免疫原性并参与病毒—宿主细胞的相互作用
文章简介宫颈癌是全球女性第二大常见恶性肿瘤,人乳头瘤病毒(HPV)是导致女性宫颈癌发生的主要原因。HPV型别众多,主要的高危型型别种类多达15种,且型别间免疫血清交叉保护能力极低,目前国际上已上市的预防性多价HPV疫苗均不能为接种者提供完全保护。长期以来,高分辨率HPV的病毒结构信息的缺乏限制了对HPV病毒的组装模式和感染机制的深入理解,进国家自然科学基金;美国国立卫生院(NIH)基金的资助
Towards prediction of ordered phases in rechargeable battery chemistry via group–subgroup transformation
Abstract: The electrochemical thermodynamic and kinetic characteristics of rechargeable batteries are critically influenced by the ordering of mobile ions in electrodes or solid electrolytes. However, because of the experimental difficulty of capturing the lighter migration ion coupled with the theoretical limitation of searching for ordered phases in a constrained cell, predicting stable ordered phases involving cell transformations or at extremely dilute concentrations remains challenging. Here, a group-subgroup transformation method based on lattice transformation and Wyckoff-position splitting is employed to predict the ordered ground states. We reproduce the previously reported Li0.75CoO2, Li0.8333CoO2, and Li0.8571CoO2 phases and report a new Li0.875CoO2 ground state. Taking the advantage of Wyckoff-position splitting in reducing the number of configurations, we identify the stablest Li0.0625C6 dilute phase in Li-ion intercalated graphite. We also resolve the Li/La/vacancy ordering in Li3xLa2/3−xTiO3 (0 < x < 0.167), which explains the observed Li-ion diffusion anisotropy. These findings provide important insight towards understanding the rechargeable battery chemistry
Molecular Dynamics Simulation Study on the Growth of Structure II Nitrogen Hydrate
Crystal growth of N-2 hydrate in a three-phase system consisting of N-2 hydrate, liquid water, and gaseous N-2 was performed by molecular dynamics simulation at 260 K. Pressure influence on hydrate growth was evaluated. The kinetic properties including the growth rates and cage occupancies of the newly formed hydrate and the diffusion coefficient and concentration of N-2 molecules in liquid phase were measured. The results showed that the growth of N-2 hydrate could be divided into two stages where N(2 )molecules in gas phase had to dissolve in liquid phase and then form hydrate cages at the liquid-hydrate interface. The diffusion coefficient and concentration of N-2 in liquid phase increased linearly with increasing pressure. As the pressure rose from 50 to 100 MPa, the hydrate growth rate kept increasing from 0.11 to 0.62 cages.ns(-1).angstrom(-2) and then dropped down to around 0.40 cages.ns(-1).angstrom(-2) once the pressure surpassed 100 MPa. During the hydrate formation, the initial sII N-2 hydrate phase set in the system served as a template for the subsequent growth of N(2 )hydrate so that no new crystal structure was found. Analysis on the cage occupancies revealed that the amount of cages occupied by two N-2 molecules increased evidently when the pressure was above 100 MPa, which slowed down the growth rate of hydrate cages. Additionally, a small fraction of defective cages including two N-2 molecules trapped in 5(12)6(5) cages and three N-2 molecules trapped 5(12)6(8) cages was observed during the hydrate growth
Construction of Three-Dimensional Network Structure in Polyethylene-EPDM-Based Phase Change Materials by Carbon Nanotube with Enhanced Thermal Conductivity, Mechanical Property and Photo-Thermal Conversion Performance
High thermal conductivity and good mechanical properties are significant for photo-thermal conversion in solar energy utilization. In this work, we constructed a three-dimensional network structure in polyethylene (PE) and ethylene-propylene-diene monomer (EPDM)-based phase change composites by mixing with a carbon nanotube (CNT). Two-dimensional flake expanded graphite in PE-EPDM-based phase change materials and one-dimensional CNT were well mixed to build dense three-dimensional thermal pathways. We show that CNT (5.40%wt)-PE-EPDM phase change composites deliver excellent thermal conductivity (3.11 W m−1 K−1) and mechanical properties, with tensile and bending strength of 10.19 and 21.48 MPa. The melting and freezing temperature of the optimized phase change composites are measured to be 64.5 and 64.2 °C and the melting and freezing latent enthalpy are measured to be 130.3 and 130.5 J g−1. It is found that the composite phase change material with high thermal conductivity is conducive to the rapid storage of solar energy, so as to improve the efficiency of heat collection
miR-136-5p Regulates the Inflammatory Response by Targeting the IKKβ/NF-κB/A20 Pathway After Spinal Cord Injury
Hierarchical Capillary Coating to Biofunctionlize Drug-Eluting Stent for Improving Endothelium Regeneration
The drug-eluting stent (DES) has become one of the most successful and important medical devices for coronary heart disease, but yet suffers from insufficient endothelial cell (EC) growth and intima repair, eventually leading to treatment failure. Although biomacromolecules such as vascular endothelial growth factor (VEGF) would be promising to promote the intima regeneration, combining hydrophilic and vulnerable biomacromolecules with hydrophobic drugs as well as preserving the bioactivity after harsh treatments pose a huge challenge. Here, we report on a design of hierarchical capillary coating, which composes a base solid region and a top microporous region for incorporating rapamycin and VEGF, respectively. The top spongy region can guarantee the efficient, safe, and controllable loading of VEGF up to 1 μg/cm2 in 1 minute, providing a distinctive real-time loading capacity for saving the bioactivity. Based on this, we demonstrate that our rapamycin-VEGF hierarchical coating impressively promoted the competitive growth of endothelial cells over smooth muscle cells (ratio of EC/SMC~25) while relieving the adverse impact of rapamycin to ECs. We further conducted the real-time loading of VEGF on stents and demonstrate that the hierarchical combination of rapamycin and VEGF showed remarkable endothelium regeneration while maintaining a very low level of in-stent restenosis. This work paves an avenue for the combination of both hydrophobic and hydrophilic functional molecules, which should benefit the next generation of DES and may extend applications to diversified combination medical devices