350 research outputs found

    Surfactant-modified three-dimensional layered double hydroxide for the removal of methyl orange and rhodamine B: Extended investigations in binary dye systems

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    Dyes pollution have raised great attention due to its fatal harm on aquatic ecosystem and human health. Generally, multiple dyes (anionic dyes, cationic dyes) present in real wastewater systems. In this work, methyl orange (MO) as anionic dye and rhodamine B (RhB) as cationic dye were chosen as typical dyes to investigate the removal behavior with surfactant-modified three-dimensional MgAl layered double hydroxide (S3D-LDH) via macroscopic and microscopic analyses. Adsorption isotherms revealed that the maximum adsorption capacity of MO and RhB could reach 380.2 and 49.6 ​mg·g, respectively. The removal process between S3D-LDH and ionic dyes was identified to be a chemical reaction via adsorption kinetics. XRD and MIR demonstrated a decrease of d-spacing value and a red shift of the stretching vibration of lattice water and hydroxyl group in the MO removal and increased d-spacing and a blue shift of water with hydroxyl group in the RhB removal. X-ray photoelectron spectroscopy (XPS) revealed that the RSO peak emerged after MO adsorption and the negative bond shift of unbound sulfur of S 2p after RhB adsorption. All investigations revealed that MO adsorbed by S3D-LDH via anion exchange and hydrogen bonding whereas surface adsorption was deemed as the primary pathway for RhB. Furthermore, the MO and RhB adsorption capacity by S3D-LDH was both enhanced in binary component systems. S3D-LDH was demonstrated as a potential broad-spectrum adsorbent for the treatment of dyes wastewater

    Persistent organic pollutants removal via hierarchical flower-like layered double hydroxide: adsorption behaviors and mechanism investigation

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    Nanostructured hierarchical flower-like MgAl layered double hydroxide (HMA-LDH) was synthesized via the one-pot soft-template method and employed for the adsorption of persistent organic pollutants: anionic methyl orange (MO) and non-ionic naphthalene (NAP). The adsorption performance and mechanism comparison of MO and NAP were investigated via adsorption kinetics, isotherms, thermodynamics, and microstructural characterization. The maximum adsorption capacity of MO and NAP could reach 380.2 and 43.7 mg·g at 298 K, respectively. The kinetic studies illustrated that the adsorption equilibria reached in 2 and 1 h for MO and NAP, respectively. The adsorption isotherms indicated that HMA-LDH fitted the Langmuir model toward MO removal, while partition model for NAP. The comparative mechanism between MO and NAP were determined by X-ray diffraction (XRD), Fourier transform spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Anion exchange dominated the MO adsorption, whereas partition was deemed as the predominated mechanism for NAP. Furthermore, the recycle performance stated that HMA-LDH could be reused in five cycles in MO adsorption, while failed after two cycles for NAP. This study provided a theoretical foundation for the practical application of hierarchical flower-like LDH in the adsorption of persistent organic pollutants in the aquatic environment

    Study on Aeration Optimization and Sewage Treatment Efficiency of a Novel Micro-Pressure Swirl Reactor (MPSR)

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    This study developed a new type of micro-pressure swirl reactor (MPSR) for treating rural domestic sewage with variable water volume in northern China. The transformation of a traditional aeration tank to MPSR was mainly divided into three steps. Firstly, the aeration device was installed on one side of the aeration tank. Secondly, most of the top cover plate was sealed. Finally, the liquid level-lifting zone was set to achieve micro-pressure. The study measured the flow velocity and dissolved oxygen (DO) distribution in the main reaction zone of MPSR, studied the effects of MPSR sewage treatment in continuous operation mode and sequential batch operation mode, and analyzed the main microbial species. The experimental results showed that a stable circular circle flow and a spatial DO gradient in MPSR were formed when the aeration rate of MPSR was 0.2 m3/h. Through the MPSR sewage treatment experiment in two operation modes, it could meet the current requirements of rural environmental pollution controlled in China. Analysis of the types of microorganisms showed that microorganisms with different functions gathered in different zones of the MPSR due to the different dissolved oxygen environment and water flow environment, which further improved the ability of MPSR to simultaneously remove nitrogen and phosphorus

    Cordyceps cicadae Prevents Renal Tubular Epithelial Cell Apoptosis by Regulating the SIRT1/p53 Pathway in Hypertensive Renal Injury

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    Hypertensive renal injury is a primary etiology of end-stage renal disease, and satisfactory therapeutic strategies are urgently required. Cordyceps cicadae, a traditional Chinese herb, has potential renoprotective benefits and is widely used in the treatment of many kidney diseases. To investigate the mechanisms underlying the renoprotective effect of C. cicadae on hypertensive renal injury, we studied the effect of C. cicadae on tubular epithelial cells (TECs) in a spontaneously hypertensive rat (SHR) model and angiotensin II- (AngII-) cultured primary TECs. Our study showed that C. cicadae treatment could decrease 24-hour urine albumin, albumin-to-creatinine ratio (ACR), β2-MG level, and kidney injury molecule-1 (kim-1) level in SHR urine, alleviate interstitial fibrosis, and reduce α-smooth muscle actin (α-SMA) expression in SHR kidney. In primary TECs, medicated serum containing C. cicadae (CSM) might significantly reduce the AngII-induced production of kim-1 and neutrophil gelatinase-associated lipocalin (NGAL). Furthermore, C. cicadae treatment could decrease TEC apoptosis in SHRs as assessed by the terminal transferase-mediated biotin dUTP nick-end labeling (TUNEL) assay. CSM could inhibit caspase-3 activity and enhance cellular viability as measured by methyl thiazolyl tetrazolium in AngII-cultured TECs, suggesting that CSM might reduce the apoptosis level in TECs induced by AngII. We found that the SIRT1 expression level was markedly lowered, while the protein level of acetylated-p53 was elevated in the TECs of patients with hypertensive renal injury and SHRs. C. cicadae presented the effect of regulating the SIRT1/p53 pathway. Further SIRT1 inhibition with EX527 reversed the effect of C. cicadae on AngII-induced apoptosis. Taken together, our results indicate that C. cicadae offers a protective effect on TECs under hypertensive conditions, which may be related to its antiapoptotic effect through regulation of the SIRT1/p53 pathway

    ROS-ERK Pathway as Dual Mediators of Cellular Injury and Autophagy-Associated Adaptive Response in Urinary Protein-Irritated Renal Tubular Epithelial Cells

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    ERK, an extracellular signal-regulated protein kinase, is involved in various biological responses, such as cell proliferation and differentiation, cell morphology maintenance, cytoskeletal construction, apoptosis, and canceration of cells. In this study, we focused on ERK pathway on cellular injury and autophagy-associated adaptive response in urinary protein-irritated renal tubular epithelial cells and explored the potential mechanisms underlying it. By using antioxidants N-acetylcysteine and catalase, we found that ERK pathway was activated by a reactive oxygen species- (ROS-) dependent mechanism after exposure to urinary proteins. What is more, ERK inhibitor U0126 could decrease the release of neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), and the number of apoptotic cells induced by urinary proteins, indicating the damaging effects of ERK pathway in mediating cellular injury and apoptosis in HK-2 cells. Interestingly, we also found that the increased expression of microtubule-associated protein 1 light chain 3 (LC3)-II (a key marker of autophagy) and the decreased expression of p62 (autophagic substrate) induced by urinary proteins were reversed by U0126, suggesting autophagy was activated by ERK pathway. Furthermore, rapamycin reduced urinary protein-induced NGAL and KIM-1 secretion and cell growth inhibition, while chloroquine played the opposite effect, indicating that autophagy activation by ERK pathway was an adaptive response in the exposure to urinary proteins. Taken together, our results indicate that activated ROS-ERK pathway can induce cellular injury and in the meantime provide an autophagy-associated adaptive response in urinary protein-irritated renal tubular epithelial cells

    Efficacy of Intermittent or Continuous Very Low-Energy Diets in Overweight and Obese Individuals with Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analyses

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    Objective. This study is aimed at investigating the efficacy of a very low-energy diet (VLED) in overweight and obese individuals with type 2 diabetes mellitus (T2DM). Methods. We thoroughly searched eight electronic resource databases of controlled studies concerning the efficacy and acceptability of intermittent or continuous VLEDs in patients with T2DM compared with other energy restriction interventions. Results. Eighteen studies (11 randomized and seven nonrandomized controlled trials) with 911 participants were included. The meta-analyses showed that compared with a low-energy diet (LED) and mild energy restriction (MER), VLED is superior in the reduction of body weight (mean difference (MD) MDLED=−2.77, 95% confidence interval (CI) CILED=−4.81 to−0.72, PLED=0.008; MDMER=−6.72, 95%CIMER=−10.05 to−3.39, PMER<0.0001), blood glucose (MDLED=−1.18, 95%CILED=−2.05 to−0.30, PLED=0.008; MDMER=−6.72, 95%CIMER=−10.05 to−3.39, PMER<0.0001), and triglyceride (TG) (MDLED=−0.35, 95%CILED=−0.58 to−0.12, PLED=0.002; MDMER=−0.55, 95%CIMER=−0.93 to−0.17, PMER=0.005) levels at the end of the intervention. After the follow-up (1–5 years), no obvious difference in weight loss (MD=−0.84, 95%CI=−3.01 to 1.32, P=0.45, I2=0%) and TG level (MD=−0.25, 95%CI=−0.55 to 0.06, P=0.12, I2=0%) between VLEDs and LEDs was evident, but VLED is more effective in glycemic control (MD=−1.43, 95%CI=−2.65 to−0.20, P=0.02). Compared to bariatric surgery, VLEDs offered comparable effects on weight loss (MD=2.51, 95%CI=−9.52 to 14.54, P=0.37), glycemic control (MD=0.37, 95%CI=−0.22 to 0.96, P=0.22), TG (MD=−0.3, 95%CI=−0.74 to 0.17, P=0.7), and insulin resistance improvement (MD=−1, 95%CI=−2.7 to 0.7, P=0.25). Conclusion. Dietary intervention through VLEDs is an effective therapy for rapid weight loss, glycemic control, and improved lipid metabolism in overweight and obese individuals with T2DM. Thus, VLEDs should be encouraged in overweight and obese individuals with T2DM who urgently need weight loss and are unsuitable or unwilling to undergo surgery. As all outcome indicators have low or extremely low quality after GRADE evaluation, further clinical trials that focus on the remission effect of VLEDs on T2DM are needed

    para-Quinodimethane- Bridged Perylene Dimers and Pericondensed Quaterrylenes: The Effect of the Fusion Mode on the Ground States and Physical Properties

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    Polycyclic hydrocarbon compounds with a singlet biradical ground state show unique physical properties and promising material applications; therefore, it is important to understand the fundamental structure/biradical character/physical properties relationships. In this study, para-quinodimethane (p-QDM)-bridged quinoidal perylene dimers 4 and 5 with different fusion modes and their corresponding aromatic counterparts, the pericondensed quaterrylenes 6 and 7, were synthesized. Their ground-state electronic structures and physical properties were studied by using various experiments assisted with DFT calculations. The proaromatic p-QDM-bridged perylene monoimide dimer 4 has a singlet biradical ground state with a small singlet/triplet energy gap (-2.97 kcal mol(-1)), whereas the antiaromatic s-indacene-bridged N-annulated perylene dimer 5 exists as a closed-shell quinoid with an obvious intramolecular charge-transfer character. Both of these dimers showed shorter singlet excited-state lifetimes, larger two-photon-absorption cross sections, and smaller energy gaps than the corresponding aromatic quaterrylene derivatives 6 and 7, respectively. Our studies revealed how the fusion mode and aromaticity affect the ground state and, consequently, the photophysical properties and electronic properties of a series of extended polycyclic hydrocarbon compounds
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