Water pollution by toxic organic dyes is one of the most critical health and environmental problems worldwide. By means of molecular dynamics method, the present work aims to evaluate the ...applicability of montmorillonite (Mt) modified by hexadecyltrimethylammonium cations (HDTMA+) compared to unmodified Na-Mt for the adsorption of cationic methylene blue (MB) dye. The results showed that the adsorption energy of MB on both HDTMA-Mt and Na-Mt absorbent ranged from − 100 to − 250 kJ/mol, indicating the effectiveness of two types of adsorbents in dye water treatment. The highest adsorption energy was found at w = 50% in each adsorbent system. Adsorption mechanisms of MB depend on molecular orientations, which is influenced by the surfactant and water content. The adsorption mechanism of MB is chemisorption dominated by strong electrostatic interaction between CH3 groups of MB and oxygen atoms of Mt surfaces. Besides, physisorption also plays a minor role in MB orientations. It is found that the existence of cationic surfactants can slightly improve the adsorption capacity of MB only at higher water content through enlarging the interlayer space of Mt and reducing mobility of MB. However, there will be a negative impact on the reduction of adsorption sites for dyes especially at low water content. Our results provide a possible application for swelling clay minerals being a promising adsorbent for dyes-surfactants co-existing wastewater treatment.
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•The dynamic adsorption processes of MB dye on HDTMA-Mt and Na-Mt are simulated.•There is no significant enhancement for the adsorption energy of MB in the presence of surfactants.•MB molecular orientations are influenced by both surfactant and water content.•The adsorption mechanism of MB is chemisorption dominated by strong electrostatic interaction.
The NF-E2-related factor 2 (Nrf2)-mediated signalling pathway provides living organisms an efficient and pivotal line of defensive to counteract environmental insults and endogenous stressors. Nrf2 ...coordinates the basal and inducible expression of antioxidant and Phase II detoxification enzymes to adapt to different stress conditions. The stability and cellular distribution of Nrf2 is tightly controlled by its inhibitory binding protein Kelch-like ECH-associated protein 1. Nrf2 signalling is also regulated by posttranslational, transcriptional, translational and epigenetic mechanisms, as well as by other protein partners, including p62, p21 and IQ motif-containing GTPase activating protein 1. Many studies have demonstrated that Nrf2 is a promising target for preventing carcinogenesis and other chronic diseases, including cardiovascular diseases, neurodegenerative diseases and pulmonary injury. However, constitutive activation of Nrf2 in advanced cancer cells may confer drug resistance. Here, we review the molecular mechanisms of Nrf2 signalling, the diverse classes of Nrf2 activators, including bioactive nutrients and other chemicals, and the cellular functions and disease relevance of Nrf2 and discuss the dual role of Nrf2 in different contexts.
Commonly used miRNA detection methods cannot be applied for high-throughput analyses. However, this study was aimed to performed a liquid bead array detection system (LBAS) to detect tissue 6 miRNAs ...in non-small cell lung cancer (NSCLC).
In this study, evaluation of LBAS was performed to observe the precision, specificity, limitation and stability. Then, a total of 52 primary NSCLC patients who received resection operation without preoperative radiotherapy and chemotherapy between June 2013 and March 2014 were selected, and then the total RNA of the tissues were extracted. We prepared six NSCLC-related miRNAs for LBAS. After optimization and evaluation, LBAS was verified by detecting the relative expression levels of 6 microRNAs in the pathological tissues and corresponding normal tissues of 52 NSCLC patients.
The results of evaluation of LBAS showed that the Mean Fluorescence Intensity (MFI) of the reaction only added with chimeric probes and beads showed no significant change after 180 days (P > 0.05). And the intra-assay Coefficient of Variation (CV) was between 1.57 and 3.5%, while the inter-assay CV was between 4.24 and 11.27%, indicating this system was ideal for diagnostic reagents. In addition, only the beads corresponding to the additional miRNAs showed high MFIs from 8426 to 18,769, whereas the fluorescence values of the other beads were under background levels (MFIs = 20 to 55) in each reaction, indicating no cross reactivity among the miRNAs. The limit of detection of miR-21, miR-210, miR-125b, miR-155, miR-375, and miR-31 were 5.27, 1.39, 1.85, 2.01, 1.34, and 2.73 amol/μL, respectively, showing that the lowest detection limit of miRNA by this system was under pM level. Then, the relative expression levels of miR-21, miR-210, miR-125b, miR-155, miR-375, and miR-31 by using this system were significantly correlated with NSCLC (P < 0.05). And the results of AUC method indicated that specific of the LBAS system was 94.2%.
Our findings suggest that LBAS was simple, high-throughput, and freely combined with absolute quantification. Thus, this system could be applied for tumor miRNAs detection.
Cytosolic calcium signaling is critical for regulating downstream responses in plants encountering unfavorable environmental conditions.
In a genetic screen for Arabidopsis thaliana mutants defective ...in stress-induced cytosolic free Ca2+ (Ca2+cyt) elevations, we identified the R2R3-MYB transcription factor MYB30 as a regulator of Ca2+cyt in response to H2O2 and heat stresses.
Plants lacking MYB30 protein exhibited greater elevation of Ca2+cyt in response to oxidative and heat stimuli. Real-time reverse transcription–polymerase chain reaction (RT-PCR) results indicated that the expression of a number of ANNEXIN (ANN) genes, which encode Ca2+-regulated membrane-binding proteins modulating cytosolic calcium signatures, were upregulated in myb30 mutants. Further analysis showed that MYB30 bound to the promoters of ANN1 and ANN4 and repressed their expression. myb30 mutants were sensitive to methyl viologen (MV) and heat stresses. The H2O2- and heat-induced abnormal Ca2+cyt in myb30 was dependent on the function of ANN proteins. Moreover, the MV and heat sensitivity of myb30 was suppressed in mutants lacking ANN function or by application of LaCl3, a calcium channel blocker.
These results indicate that MYB30 regulates oxidative and heat stress responses through calcium signaling, which is at least partially mediated by ANN1 and ANN4.
The diffusion, storage, and seepage of water in clay are closely related to the coupling effect of clay mineral and water molecules. However, the anisotropic adsorption mechanism of kaolinite crystal ...remains unclear. This study focuses on the microscopic interattraction property of kaolinite and water molecules using molecular dynamics (MD) simulation method. Three nano-scale kaolinite-water models were established to investigate the adsorption behavior of six surfaces with pore water. According to the interaction energy of clay-water, the adsorption of four edge surfaces is significantly greater than that of two basal surfaces. The anisotropic adsorption characteristics mainly stem from different atomic arrangements along different crystal orientations, forming different electrostatic adsorption and hydrogen bonding effects. Then, the adsorption topological structure of six surfaces was deeply characterized. From the density and potential energy distribution of pore water, the surfaces of kaolinite can adsorb one layer of strongly bound water and weakly bound water. Besides, the diffusion coefficient of water molecules decreases with the increase of the micro-specific surface area of kaolinite crystal, which is consistent with the macroscopic experimental results.
Ni single atoms are anchored on ultrathin g-C3N4 to obtain high selective H2O2 production through a one-step 2e− O2RR process.
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•Morphology modification and single atoms contribute ...superior photocatalytic H2O2 production.•H2O2 production is through a one-step two-electron reduction pathway with selectivity of 87.3 %.•A high H2O2 generation rate of 27.11 mmol g−1h−1 and AQY of 8.56% are obtained in neutral condition.•NiCN-4 catalyst shows photocatalytic activities of both H2O2 production and TC degradation.
Photocatalysis technology provides a promising and effective method for hydrogen peroxide (H2O2) production. Nevertheless, the photocatalytic H2O2 production activity is greatly regulated by the two-electron oxygen reduction reaction (2e− O2RR). Herein, we demonstrate a robust single atom photocatalyst (NiCN-x, Ni single atoms anchored on ultrathin g-C3N4) for artificial H2O2 production under visible light irradiation. A high H2O2 generation rate of 27.11 mmol g−1h−1 and an apparent quantum yield (AQY) of 8.56 % at 400 nm are both obtained in the optimal NiCN-4 photocatalytic system. Furthermore, NiCN-4 catalyst shows relatively high selectivity of H2O2 with 87.3 % through using a rotating ring-disk electrode (RRDE) measurement. Furthermore, NiCN-4 shows enhanced photocatalytic TC decomposition with degradation efficiency of 89.4 %. Based on DFT calculation, experimental results and advanced characterizations, we find that the high photocatalytic performance is attributed to the boosting 2e−O2RR process with the formation of Ni-μ-peroxide (Ni-OOH) and the unique electronic feature of Ni-Nx coordination sites. This study offers a new blueprint for the fabrication of single atom catalysts (SACs) to achieve artificial photosynthesis of H2O2 with high selectivity and degradation of organic pollutants.
The fiber‐reinforced polymer (FRP) has attracted much attention in civil engineering due to its durability and cost‐effectiveness. The soil–FRP structure interface plays an essential role when the ...FRP is adopted in geotechnical engineering, but its fundamental interfacial behavior remains unclear. In the present study, the atomistic models of silica representing sand, water film representing the lubricated condition, and cross‐linked epoxy representing FRP are constructed to investigate the FRP–sand interfacial properties at the nano‐scale through molecular dynamics (MD) simulations. The epoxy model geometry and forcefield are first validated by comparing the thermodynamic and mechanical parameters with experimental and simulation measurements. The silica–epoxy interfacial tribological and rheological behavior is then explored by conducting friction and creep simulations under dry and lubricated conditions. The friction force has been found linearly dependent on the normal load and increases with the sliding velocity while decreasing against water content. The modified Amontons law for the adhering surface could describe the silica–epoxy interfacial friction well. The shear stress level influences the creep characteristics with primary, secondary, and tertiary (or rupture) creep modes. The results of this study at the nano‐scale can be further developed to enhance the current contact laws of sand–FRP structure in micromechanics‐based modeling approaches.
Colorectal cancer (CRC) is one of the most prevalent cancers worldwide and Alpha B-crystallin (CRYAB) protein has been identified as a prognostic biomarker for CRC. We evaluated CRYAB C-802G ...(rs14133)polymorphism in association with CRC risk and survival in Chinese population. We genotyped for CRYAB C-802G (rs14133), A-1215G (rs2228387) and intron 2 (rs2070894), and assessed their associations with CRC in a case-control study of 441 CRC cases and 500 healthy controls. We also analyzed this polymorphism in relation to overall survival in CRC patients. A significantly different frequency distribution was found in CRYAB C-802G genotypes, but not in A-1215G and intron2 genotypes, between the cases and the controls. Under multivariable logistic regression adjusted for age and gender, CG/GG genotype carriers were associated with increased risk of CRC (OR 1.754, 95% CI 1.338-2.301, P < 0.001) when compared with CC genotype carriers. Multivariate Cox proportional hazards model showed that patients with CG/GG genotype had significant shorter survival time than those with CC genotype, after adjustment for gender and TNM stage (HR 2.347, 95% CI 1.719-3.204, P < 0.001), and after adjustment for gender and tumor grade (HR 2.871, 95% CI 2.121-3.887, P < 0.001), respectively. Our results demonstrated that CG/GG at CRYAB C-802G is correlated with CRC susceptibility and this polymorphism may be an useful marker for clinical outcome of CRC.
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