We investigate the influence of slide rings on the stretching behavior of a single-chain polyrotaxane anchored by a fix ring. The extension of the force side in our simulations is in line with the ...previous theoretical framework. However, the end-to-end distance on the free side shows a discrepancy. To address this, we include the excluded-volume effect, successfully aligning with theoretical predictions. We propose a comprehensive model that incorporates excluded-volume effects for rings on both the free side and the force side. The model demonstrates qualitative consistency with simulation data, highlighting the competition among rings from each side. The force-side rings exert a significant influence on the extension of the force side, as derived from the excluded-volume effects. These findings of greater force responsiveness of force-side rings have potential implications for the design of slide-ring gels.
Electron beam （EB） degradation of perfluo- rooctanoic acid （PFOA） and perfluorooctane sulfonate （PFOS） in aqueous solutions was studied. It suggested that PFOA and PFOS degradation followed the ...pseudo-first- order kinetics, and degradation rates increased with increasing initial pH. Radical scavengers＇ experiments indicated that hydrated electron and hydrogen radical were important in the electron beam degradation of PFOA and PFOS, especially hydrated electron. The decomposition efficiencies were 95.7% for PFOA and 85.9% for PFOS, by EB irradiation in an anoxic alkaline solution （pH = 13）. The potential degradation pathways of PFOA and PFOS by electron beam irradiation through defluorination and the removal of CH2 unit were proposed.
Summary
Indole is well known as an interspecies signalling molecule to modulate bacterial physiology; however, it is not clear how the indole signal is perceived and responded to by plant growth ...promoting rhizobacteria (PGPR) in the rhizosphere. Here, we demonstrated that indole enhanced the antibiotic tolerance of Pseudomonas fluorescens 2P24, a PGPR well known for its biocontrol capacity. Proteomic analysis revealed that indole influenced the expression of multiple genes including the emhABC operon encoding a major multidrug efflux pump. The expression of emhABC was regulated by a TetR‐family transcription factor EmhR, which was demonstrated to be an indole‐responsive regulator. Molecular dynamics simulation showed that indole allosterically affected the distance between the two DNA‐recognizing helices within the EmhR dimer, leading to diminished EmhR–DNA interaction. It was further revealed the EmhR ortholog in Pseudomonas syringae was also responsible for indole‐induced antibiotic tolerance, suggesting this EmhR‐dependent, indole‐induced antibiotic tolerance is likely to be conserved among Pseudomonas species. Taken together, our results elucidated the molecular mechanism of indole‐induced antibiotic tolerance in Pseudomonas species and had important implications on how rhizobacteria sense and respond to indole in the rhizosphere.
Paocai is one of the most popular traditional fermented products in China. Different lactic acid bacteria (LAB) have an important influence on the microbial changes, the dynamic changes of ...metabolites, and the sensory qualities of paocai. In this study, five different paocai groups were designed which were fermented by Lactobacillus plantarum DMDL 9010 (LP), Lactobacillus brevis GIM 1.773 (LB), Leuconostoc mesenteroides GIM 1.774 (LM), mixed three kinds of LAB (LP + LB + LM), pasteurization (PST) and natural fermentation (NF) without LAB. The nitrite, nitrate, pH, titratable acidity, viable count (LAB and yeast) and metabolites (organic acids, sugars and volatile substances) of these paocai groups were measured. Compared with each single bacterial fermentation (LP, LB and LM), NF and PST, the mixed three kinds of LAB (LP + LB + LM) had a lower nitrite peak, which could be attributed to the significant accumulation of organic acids, and positively affected sensory quality of paocai. Flavor substances produced in paocai samples confirmed as alcohols, ketones and olefins. Sensory evaluation showed that multi-bacteria mixed fermentation of paocai had a better flavor than that of NF, PST and single bacterial fermentation. Therefore, the use of multiple LAB as starter cultures contributes to enhance paocai qualities and control the levels of nitrite.
•Effect of different lactic acid bacteria (LAB) on nitrite degradation and quality in paocai.•The three kinds of LAB mixed fermentation could significantly reduce the content of nitrite.•Natural fermentation and multi-bacterial mixed fermentation of paocai had a better flavor than single-bacterial fermentation.
Leaves of the natural plant lotus are used in traditional Chinese medicine and tea production. They are rich in flavonoids.
In this study, lotus leaf flavonoids (LLF) were applied to human lung ...cancer A549 cells and human small cell lung cancer cells H446 in vitro to verify the effect of LLF on apoptosis in these cells through the ROS/p38 MAPK pathway.
LLF had no toxic effect on normal cells at concentrations up to 500 µg/mL, but could significantly inhibit the proliferation of A549 cells and H446 cells. Flow cytometry showed that LLF could induce growth in A549 cells. We also found that LLF could increase ROS and MDA levels, and decrease SOD activity in A549 cells. Furthermore, qRT-PCR and western blot analyses showed that LLF could upregulate the expression of p38 MAPK (p-p38 MAPK), caspase-3, caspase-9, cleaved caspase-3, cleaved caspase-9 and Bax and downregulate the expression of Cu/Zn SOD, CAT, Nrf2, NQO1, HO-1, and Bcl-2 in A549 cells. Results of HPLC showed that LLF mainly contain five active substances: kaempferitrin, hyperoside, astragalin, phloridzin, and quercetin. The apoptosis-inducing effect of LLF on A549 cells came from these naturally active compounds.
We have shown in this study that LLF is a bioactive substance that can induce apoptosis in A549 cells in vitro, and merits further research and development.
Objective: To study whether miR-21 targets and inhibits tumor suppressor gene PTEN can promote prostate cancer cell proliferation and invasion,Methods: Prostate cancer cell lines PC-3 were cultured ...and divided into negative control group(NC group),miR-21 group,pc DNA3.1 group,miR-21+pc DNA3.1 group and miR-21+PTEN group that were transfected with different mi R and plasmid,respectively,After 12 h and 24 h of transfection,the cell viability and invasive cell number were determined; after 24 h of transfection,Bcl-2,Survivin,MMP2,MMP9,PTEN,PI3 K,and AKT expression in cells were determined,Results: After 12 h and 24 h of transfection,OD value and invasive cell number of miR-21 group were significantly higher than those of NC group; after 24 h of transfection,Bcl-2,Survivin,MMP2,MMP9,PI3 K and AKT expression levels were significantly higher than those of NC group while PTEN expression level was significantly lower than that of NC group; after 12 h and 24 h of transfection,OD value and invasive cell number of mi R-21+pcDNA3.1 group were significantly higher than those of pc DNA3.1 group,and the OD value and invasive cell number of mi R-21+PTEN group were significantly lower than those of mi R-21+pcDNA3.1 group; after 24 h of transfection,Bcl-2,Survivin,MMP2 and MMP9 content of mi R-21+pc DNA3.1 group were significantly higher than those of pcDNA3.1 group,and Bcl-2,Survivin,MMP2 and MMP9 content of miR-21+PTEN group were significantly lower than those of mi R-21+pcDNA3.1 group,Conclusions: miR-21 can target and inhibit tumor suppressor gene PTEN expression to promote prostate cancer cell proliferation and invasion.
The transformation of a large-volume industrial by-product and stable greenhouse gas fluoroform (HCF
) to useful products has recently received significant attention. Now, a simple and scalable ...preparation of AgCF
by treatment of HCF
with t-BuOK and AgOAc is disclosed. The reactivity of the HCF
-derived AgCF
has been demonstrated by hydrotrifluoromethylation of alkenes and C-H trifluoromethylation of (hetero)arenes. This work not only provides a new avenue for the utilization of HCF
, but also presents a reliable and easy-to-execute synthesis of the relatively stable AgCF
solution.
In order to avoid the property degradation resulting from high‐temperature joining process, nano‐infiltrated transient eutectoid (NITE) phase with the Al2O3‐Ho2O3 as the joining adhesives was adopted ...to join silicon carbide (SiC) ceramics with the attempts to lower down the joining temperature. The liquid‐phase‐sintered silicon carbide (LPS‐SiC) specimens were joined at 1500‐1800°C by spark plasma sintering (SPS) under the pressure of 20 MPa. The results of the shear test and microstructure observation showed that the joining process could be finished at a relatively lower temperature (1700°C) compared to other NITE‐phase joining. In contrast to the shear strength of 186.4 MPa derived from the SiC substrate, the joint exhibited the shear strength of 157.8 MPa with the fully densified interlayer.
A novel difluoroboron fluorophore with an electron donor-acceptor conjugated structure was synthesized with 26.5% fluorescence quantum yield, 18 035 GM two-photon absorbing cross-section, and ...undetectable two-photon fluorescence, resulting in 25%
1
O
2
quantum yield. The unique optical behavior of CNFBBN enabled one-photon fluorescence imaging and two-photon phototherapy against HeLa cancer cells, irradiated at separate wavelengths.
A facile strategy has been proposed to realize two-photon phototherapy against HeLa cancer cells with simultaneous one-photon fluorescence imaging modality at separate irradiation channels.
The bolted joints of angle steel transmission tower will slide relatively under load, that is, the bolt-slippage effect. The existing research on the bearing capacity of transmission towers often ...ignores the bolt-slippage effect, resulting in deviations in the analysis of the bearing capacity of transmission towers. To evaluate the bearing capacity of transmission tower more accurately, the finite element model of transmission tower considering bolt-slippage effect and the finite element ideal rigid frame model of transmission tower without considering bolt-slippage effect are established. The distribution and stress changes of failure members of the two models under static wind load and longitudinal unbalanced tension caused by uneven icing and wire breakage under different settlement modes and settlement amounts are calculated. The difference of bearing capacity between the two models is compared and analyzed, and the influence of bolt slippage and foundation settlement on the two models is obtained. The results show that the bolt-slippage effect will significantly increase the deformation and displacement response of the transmission tower, and at the same time affect the stress distribution of the members, resulting in the failure position and failure mode of the members of the two models are not exactly the same. Ignoring the bolt-slippage effect will overestimate the bearing capacity of the transmission tower-line system. The bolt-slippage effect makes the bearing capacity of the tower-line system decrease more slowly with the settlement. To calculate the bearing capacity of the tower-line system more accurately, the bolt-slippage effect cannot be ignored.
PDF
