The leaves of Pall. are widely used as tea substitutes in northwest China for their fragrant aroma, anti-irritability, and digestion-enhancing properties. Ombuin, a main flavonoid compound found in the leaves, exhibited notable anti-inflammatory and antioxidant effects.
View Article and Find Full Text PDFHerein, we constructed a novel aminofluorene-based fluorescence probe (FEN-CE) for the detection of carboxylesterase (CE) in living cells by a ratiometric near-infrared (NIR) fluorescence signal. FEN-CE with NIR emission (650 nm) could be hydrolyzed specifically by CE and transformed to FENH with the release of the self-immolative group, which exhibited a red-shifted emission peak of 680 nm. In addition, FEN-CE showed high selectivity for CE and was successfully used in the detection of CE activity in living cells through its ratiometric NIR fluorescence signals.
View Article and Find Full Text PDFThe sintering of hydrate aggregates on the pipe wall is a major form of hydrate deposition. Understanding the sintering behavior of hydrates on the wall is crucial for promoting hydrate safety management and preventing pipeline blockage. However, limited research currently exists on this topic.
View Article and Find Full Text PDFA magnetic field and pour point depressant, as a new avenue for improving the submarine pipeline flow of waxy oils, has attracted increasing attention along with the development of efficient wax mitigation techniques. Although advances have been made recently in understanding the rheological behavior and crystallization properties of waxy oils, the effect of magnetic field and pour point depressants on wax deposition remains an open question. In this work, a ferromagnetic nanocomposite pour point depressant (FNPPD) was prepared.
View Article and Find Full Text PDFThis study explores how the micro-distribution change of wax crystals from the continuous oil phase to the oil-water interface mitigates the macro wax deposition of an emulsion. Two types of interfacial actions between wax crystals and water droplets, interfacial adsorption and interfacial crystallization, which were induced by two different emulsifiers, sorbitan monooleate (Span 80) and sorbitan monostearate (Span 60), respectively, were detected by differential scanning calorimetry and microscopy observation. The wax interfacial crystallization promoted by Span 60 resulted in the wax being nucleated directly at the oil-water interface prior to the continuous oil phase, conferring the nascent wax crystals and water droplets to be combined as coupled particles.
View Article and Find Full Text PDFThe hydrate formation rate is the key to the implementation of solid gas storage and transportation technology by the hydrate method. As a MOF material with strong hydrothermal stability, ZIF-8 has been proved to play a significant role in promoting the nucleation and growth of hydrate. However, the growth kinetics promotion mechanism and growth law of methane hydrate in the ZIF-8 promoter system have not been clarified at present.
View Article and Find Full Text PDFIn the exploitation of deep-sea oil and gas resources, the multiphase production and transportation process is frequently plagued by pipeline blockage issues. Especially when hydrates and wax coexist simultaneously, the viscosity and plugging tendency of multiphase flow systems will synergistically increase. Understanding the evolution of morphology of hydrate particles and the agglomeration characteristics of hydrate particles in the presence or absence of wax crystals is crucial to flow assurance industry.
View Article and Find Full Text PDFSurfactants promote the production of hydrates, which provide a possibility for the industrialization of hydrate technology. In this paper, methane and CO hydrate formation experiments were carried out, respectively, with surfactant-dioctyl sodium sulfosuccinate (DSS) using a visual experimental apparatus at a constant pressure. This study explored the influence of the surfactant dosage, experimental pressure, and subcooling temperature on the dynamic characteristics of hydrate formation.
View Article and Find Full Text PDFHydrate slurry transport technology has become a focal point among worldwide researches, due to its high economic efficiency. However, the mechanism and law of hydrate growth kinetics in flow systems were still unclear, especially in high water-cut oil-water systems with hydrate promoters. On this basis, this paper conducted a series of growth kinetic experiments using a high-pressure transparent sapphire cell, and investigated systematically several influencing factors (such as initial pressure, the concentration of emulsifier, hydrate promoter, and the concentration of hydrate promoter) of growth kinetics, and obtained the quantitative relationship between these factors and gas consumption as well as the hydrate growth rate (gas consumption rate).
View Article and Find Full Text PDFIn this work, to solve the problem of pipeline blockage caused by the accumulation of hydrate particles and wax particles and to explore the interaction characteristics of adhesive force between gas hydrate particles and wax particles as well as droplets, a high-pressure triaxial mobile device was used to measure the adhesion strength between cyclopentane hydrate particles and different commonly seen phases in the pipeline, including cyclopentane hydrate particles themselves, liquid droplets, and wax crystal particles. These experiments were conducted at different temperatures. The results showed that the adhesion between hydrate and wax particles was decreased with the increase in temperature; this is because the wax is amorphous, the heat absorbed when the temperature rises only increases its average kinetic energy, and the stronger the kinetic energy, the lower its viscosity, resulting in reduced adhesion between particles.
View Article and Find Full Text PDFAdding low dosage hydrate inhibitors to the hydrate systems makes the generated hydrate particles more uniformly dispersed in the liquid phase, which can significantly reduce the hydrate accumulation and blockage in oil and gas pipelines. The effect of surfactant hydrophile-lipophilic balance (HLB) values on hydrate flow characteristics was studied with a flow loop. The experimental results showed that there was a critical HLB value.
View Article and Find Full Text PDFIn order to explore the growth kinetics characteristics of NGH (natural gas hydrate) in an oil and gas mixed transportation pipeline and ensure the safe transportation of the pipeline, with the high-pressure hydrate experimental loop, an experimental study on the growth characteristics of NGH in an oil-water emulsion system was carried out, and the effects of pressure, flow rate, and water cut on the hydrate induction time, gas consumption, consumption rate, and hydrate volume fraction were explored, and important experimental rules were obtained. The experiment was divided into three stages: in the rapid formation stage of the hydrate, the temperature and gas consumption rose sharply, and the pressure dropped suddenly. The induction time decreased with the increase of pressure, flow rate, and water cut.
View Article and Find Full Text PDFObjective: To investigate whether pyroptosis is induced by Porphyromonas gingivalis-lipopolysaccharide (P. gingivalis-LPS)/ adenosine triphosphate (ATP) through NF-κB/NLRP3/GSDMD signaling in human gingival fibroblasts (HGFs) and whether isoliquiritigenin (ISL) alleviates pyroptosis by inhibition of NF-κB/NLRP3/GSDMD signals.
Design: Periodontitis was optimally simulated using a combination of P.
Objective: To investigate the effects of hypoxia and Porphyromonas gingivalis- lipopolysaccharide (P. gingivalis-LPS) on activation of the NACHT leucine-rich repeat protein 3 (NLRP3) inflammasome in human gingival fibroblasts (HGFs).
Design: Periodontitis was optimally simulated using a hypoxic concentration of 1%.
As an important component of crude oil, asphaltene precipitation and deposition are harmful to petroleum production and processing. In previous research, the impacts of asphaltene precipitation on crude oil characteristics were preliminarily explored. In this paper, by mixing different types of crude oil, the dynamic process of asphaltene precipitation and its effect on the crystallization and gelation behaviors of mixed crude oil were in-depth analyzed and discussed using the high-speed centrifugation technique, microscopic observation, differential scanning calorimetry (DSC) thermal analysis, and rheological test.
View Article and Find Full Text PDFHydrate slurry decomposition in flow systems is a significant subject that involves flow assurance and development of marine natural gas hydrates. Firstly, the decomposition mechanism of hydrate slurry is studied in this work, and it is proposed that desorption of the gas from the surface of the decomposed hydrate particles might be the main reason for the coalescence of particles and water droplets during the hydrate slurry decomposition. Secondly, a hydrate slurry decomposition kinetic model comprehensively considering the influencing factors (, the intrinsic kinetics, heat and mass transfer) is proposed in this work, based on the classic intrinsic kinetic model and the hydrate slurry dissociation experiments conducted in a flow loop system.
View Article and Find Full Text PDFWhen the hot oil pipeline is running at a low throughput, it easily enters into an unstable condition, which seriously threatens the safety of the hot oil pipeline operation. In this study, the unsteady heat transfer and flow mathematical models for the hot oil pipeline system were established first by comprehensively considering the uncertainty of parameters during pipeline operation, such as the operating parameters (throughput and oil temperature), physical properties of crude oil (freezing point, viscosity, and thixotropic parameters), and environmental parameters (buried deep soil temperature and soil thermal conductivity). Then, the efficient Latin hypercube sampling (LHS) stochastic numerical algorithm was applied and further developed to quantitatively describe the operation safety of hot oil pipelines with low throughput in the form of probability.
View Article and Find Full Text PDFHydrate growth is influenced by many factors, including thermodynamics, kinetics, mass and heat transfer, and so on. There is thus a practical significance in establishing a model that comprehensively considers these influencing factors for hydrate crystal growth in multiphase transportation pipelines. On this basis, this paper presents a more practical and comprehensive bidirectional growth model of hydrate shells for an actual pipeline system.
View Article and Find Full Text PDFColloids Surf B Biointerfaces
April 2020
The cleaning and physicochemical properties on tooth root biointerfaces are pivotal for periodontal healing. Herein, this work investigated the impact of multi-treatment on the physicochemical features of tooth root surfaces and the responsive behavior of human gingival fibroblasts (hGFs). It was found that the combination of various mechanical treatments significantly affects the topographical pattern and size as well as wettability on tooth root surfaces.
View Article and Find Full Text PDFThe effects of a new promoter on the growth kinetics of methane hydrates were investigated using a visualized constant-pressure autoclave. The experimental results show that when the 1#, 2# and 3# unit promoter was compounded at a ratio of 2 : 1 : 1, the induction time was shortened greatly from 30 h to 0.64 h compared to the no promoter situation.
View Article and Find Full Text PDFThe formation and accumulation of hydrates in high pressure oil and gas pipelines bring great risks to field development and deep-water transportation. In this paper, a high pressure flow loop equipped with visual window was used to study the growth process of hydrates in a pipe flow system and slurry flow characteristics. Deionized water, industrial white oil and CO were selected as the experiment medium.
View Article and Find Full Text PDFIntroduction: Nipple fissure and nipple pain are common complaints among breastfeeding mothers. Studies found that mupirocin was effective in preventing and treating infections of damaged nipple and nipple pain. Acidic fibroblast growth factor (aFGF) plays an important role in wound healing.
View Article and Find Full Text PDFIn order to better understand the process of carbon dioxide hydrate formation and blockage, a series of experiments were performed in a high pressure hydrate experimental loop which has been constructed. The impacts of varying flow rate, pressure, and restarting of the pump on the plugging have been studied in this paper. The particle chord length distribution in the process of hydrate formation and blockage was monitored in real time by using the advanced device, Focused Beam Reflectance Measurement (FBRM).
View Article and Find Full Text PDFHydrate slurry transport technology in deep-water pipelines has become a focal point among worldwide researches, due to its high economic efficiency. However, as the key part of the hydrate slurry transport technology research, the mechanism and laws of natural gas hydrate growth dynamics are still unclear in the flow emulsion system. On this basis, we have conducted a series of growth kinetic experiments in a high-pressure loop, investigated systematically several influencing factors ( the flow rate, water-cut, AA concentration and so on) of growth kinetics, obtained the quantitative relations between these factors and the gas consumption as well as the hydrate growth rate (gas consumption rate).
View Article and Find Full Text PDFThis study, for the first time, demonstrated a continuously accelerated Fe(0) corrosion driven by common oxidants (i.e., NaClO, KMnO4 or H2O2) and thereby the rapid and efficient removal of heavy metals (HMs) by zero-valent iron (ZVI) under the experimental conditions of jar tests and column running.
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