Tannic acid-accelerated fenton chemical reaction amplification for fluorescent biosensing: The proof-of-concept towards ultrasensitive detection of DNA methylation.

As a promising biomarker, the level of methylated DNA usually changes in the early stage of the cancer. Ultrasensitive detection of the changes of methylated DNA offers possibility for early diagnosis of cancer. In this work, a tannic acid-accelerated Fenton chemical reaction amplification was firstly proposed for the construction of ultrasensitive fluorescent assay. Tannic acid was used as reductant to accelerate Fenton reaction procedure through the conversion of Fe3+/Fe2+, generating hydroxyl radicals (·OH) continuously. The produced ·OH oxidized massive non-fluorescent terephthalic acid (TA) to fluorescent-emitting hydroxy terephthalic acid (TAOH). In this way, the fluorescent signal could be greatly enhanced and the sensitivity was improved almost 116 times. The proposed signal amplification strategy was further applied to detect of DNA methylation with the assistance of liposome encapsulated with tannic-Fe3+ complexes. The methylated DNA was firstly captured through the hybridization with its complementary DNA that were pre-modified in the 96-well plate via the combination between streptavidin (SA) and biotin. Then, 5 mC antibody on the surface of liposomes specially recognized and combined with methylation sites, which brought large amount of tannic-Fe3+ complexes to participate Fenton reaction. The fluorescence of generated TAOH was depended on the concentration of methylated DNA. The assay showed good analytical performance for methylated DNA with a limit of detection (LOD) of 1.4 fM. It's believed that tannic acid-accelerated Fenton chemical reaction amplification strategy provides a promising platform for ultrasensitive fluorescent detection of low abundant biomarkers.

Reactive transport model of uranium by CO2 + O2 in situ leaching.

Uranium is an important strategic resource, and its safe and efficient development and utilization are of great significance to ensuring a nation's energy supply and strategic security. Sandstone-type uranium ore is commonly mined by CO2 + O2 in situ leaching, for which understanding the coupling mechanism between the hydrodynamic and chemical fields is key to predicting uranium leaching. This study focused on a coal-uranium ore deposit in China. A convection and dispersion model of the solute transport by in situ leaching was constructed in COMSOL, and a thermodynamic model of CO2 + O2 in situ leaching in sandstone-type uranium ore was constructed in PHREEQC. The two models were coupled to simulate the reactive transport and dynamic leaching processes of uranium by CO2 + O2 in situ leaching. A sensitivity analysis was performed to quantitatively analyze the effects of different model parameters on the uranium leaching efficiency and uranium contamination remediation. The results showed that the coupled model could simulate and predict the reaction and transport of uranium. The sensitivity analysis indicated that the production rate and the injected CO2 and O2 concentrations are the key parameters that control the uranium leaching efficiency, followed by the formation permeability and injection rate. The uranium leaching efficiency does not increase monotonically with the formation permeability and production rate. The results also indicated that natural dilution is insufficient for remediating uranium-contaminated groundwater, but the remediation efficiency can be improved by increasing solution extraction. The results of this study can be used to develop guidelines for the safe and efficient development and utilization of uranium ore while protecting the ecological environment.

[Chemical reaction mechanism of decoction of traditional Chinese medicines: a review].

Complicated chemical reactions occur in the decoction of traditional Chinese medicines(TCMs) which features complex components, influencing the safety, efficacy, and quality controllability of TCMs. Therefore, it is particularly important to clarify the chemical reaction mechanism of TCMs in the decoction. This study summarized eight typical chemical reactions in the decoction of TCMs, such as substitution reaction, redox reaction, isomerization/stereoselective reaction, complexation, and supramolecular reaction. With the "toxicity attenuation and efficiency enhancement" of aconitines and other examples, this study reviewed the reactions in decoction of TCMs, which was expected to clarify the variation mechanisms of key chemical components in this process and to help guide medicine preparation and safe and rational use of medicine in clinical settings. The current main research methods for chemical reaction mechanisms of decoction of TCMs were also summed up and compared. The novel real-time analysis device of decoction system for TCMs was found to be efficient and simple without the pre-treatment of samples. This device provides a promising solution, which has great potential in quantity evaluation and control of TCMs. Moreover, it is expected to become a foundational and exemplary research tool, which can advance the research in this field.

Research progress of microparticles in traditional Chinese medicine decoction / 药学学报

Decoction is a classical dosage form of traditional Chinese medicines. In the process of decocting, various complex components produce physical interactions and chemical reactions, among which physical interactions include van der Waals force, hydrogen bond, electrostatic interaction, π-π stacking, etc., and chemical reactions include Maillard reaction, oxidation reaction, hydrolysis reaction, degradation reaction, polymerization reaction, etc. New substances and original ingredients from chemical reactions can be further activated. These effects form the basis of particle formation in the broth. The sizes of the particles in decoctions range from nanoscale to micron scale, mostly composed of polysaccharide, protein matrix, wrapped in water insoluble molecules, can increase the dispersion of insoluble components and the stability of unstable components, as well as reduce the volatile components and toxic components of volatile components, and ultimately achieve the purpose of efficient absorption and toxicity reduction. From the angle of physical change and chemical reaction in the process of decoction, this paper expounds the formation mechanism of particles in decoction, expounds the research method of particles, analyzes the components in particles and the interaction between components, and then explains the pharmacodynamic characteristics of traditional Chinese medicine decoction, which provides the foundation for the modernization of Chinese decoction.

Chemical reaction mechanism of decoction of traditional Chinese medicines: a review / 中国中药杂志

Complicated chemical reactions occur in the decoction of traditional Chinese medicines(TCMs) which features complex components, influencing the safety, efficacy, and quality controllability of TCMs. Therefore, it is particularly important to clarify the chemical reaction mechanism of TCMs in the decoction. This study summarized eight typical chemical reactions in the decoction of TCMs, such as substitution reaction, redox reaction, isomerization/stereoselective reaction, complexation, and supramolecular reaction. With the "toxicity attenuation and efficiency enhancement" of aconitines and other examples, this study reviewed the reactions in decoction of TCMs, which was expected to clarify the variation mechanisms of key chemical components in this process and to help guide medicine preparation and safe and rational use of medicine in clinical settings. The current main research methods for chemical reaction mechanisms of decoction of TCMs were also summed up and compared. The novel real-time analysis device of decoction system for TCMs was found to be efficient and simple without the pre-treatment of samples. This device provides a promising solution, which has great potential in quantity evaluation and control of TCMs. Moreover, it is expected to become a foundational and exemplary research tool, which can advance the research in this field.

Integrating Thermal Analysis and Reaction Modeling for Rational Design of Pyrolytic Processes to Remediate Soils Contaminated with Heavy Crude Oil.

We developed a novel methodology that combines thermo-analytical measurements and mathematical methods to inform the reliable pyrolytic treatment of specific soil/contaminant systems. Our approach improves upon current "black-box" design methods that may overestimate the required treatment intensity and hinder cost efficacy. We used thermogravimetry and evolved gas analysis to characterize the complex network of soil mineral transformations, contaminant desorption, and pyrolytic reactions occurring when contaminated soils are heated in an anoxic atmosphere. The kinetics of these reactions were quantified using a distributed activation energy (DAE) approach with six pseudocomponents and used in a mathematical model for continuous-flow reactors to predict the removal of hydrocarbon contaminants without other fitting parameters. This model was tested with pilot-scale data from pyrolytic treatment of soils contaminated with crude oil and found to be a good predictor of the total petroleum hydrocarbon (TPH) removal for temperatures between 370 and 470 °C and residence times from 15 to 60 min. The light hydrocarbon fraction desorbed quickly, and over 99.7% removal was achieved at 420 °C and 15 min residence time. However, 95% removal of the heavy hydrocarbon fraction, which is a good proxy for polyaromatic hydrocarbons (PAHs), required 470 °C with 15 min residence time. This model can be employed to select operating conditions (e.g., reactor size, treatment time, and temperature) to reliably achieve remediation objectives for specific hydrocarbon/soil mixtures without inflating energy requirements, which would lower operating costs and decrease the process carbon footprint on a system-specific basis.

Development of phosphorus-based inhibitors for PCDD/Fs suppression.

Inhibition mechanisms of sulfur-, nitrogen- and phosphorus- based inhibitors on the de novo synthesis of polychlorinated dibenzo-p-dioxins, and dibenzofurans (PCDD/F) were studied by exploring speciation evolution of carbon, chorine and copper in fly ash under laboratory-scale experiments. Significant inhibition of PCDD/Fs by thiourea (TUA) and ammonium dihydrogen phosphate (ADP) was observed as 97.2% and 98.2%, respectively, except for potassium dihydrogen phosphate (PDP). ADP and PDP exhibited better inhibition on PCDFs than on PCDDs, whereas TUA exhibited the opposite effect. After adding inhibitors, the proportion of C-O/C=O/O-C=O bonds at the surface of fly ash increased, and stronger oxidation of carbon occurred, together with the conversion from Cu2+ to Cu+ and the inhibition of organic chlorine formation. Kinetic model results indicated that TUA might either suppress the carbon gasification or promote the decomposition of PCDD/Fs, resulting in a remarkable inhibition of PCDD/Fs formation. Simulated chemical reaction equilibrium further comfirmed that catalytic metal could be deactivated into CuS and Cu2S by sulfur, and into Cu2P2O7 by phosphorus. Moreover, NH3, decomposed from TUA and ADP, was able to convert Cl2 into HCl, albeit with a weaker chlorination ability. This study of inhibition mechanisms is useful for the exploration and utilization of efficient inhibitors in full-scale incinerators.

Improved ADM1 model for anaerobic digestion process considering physico-chemical reactions.

The "Anaerobic Digestion Model No. 1" (ADM1) was modified in the study by improving the bio-chemical framework and integrating a more detailed physico-chemical framework. Inorganic carbon and nitrogen balance terms were introduced to resolve the discrepancies in the original bio-chemical framework between the carbon and nitrogen contents in the degraders and substrates. More inorganic components and solids precipitation processes were included in the physico-chemical framework of ADM1. The modified ADM1 was validated with the experimental data and used to investigate the effects of calcium ions, magnesium ions, inorganic phosphorus and inorganic nitrogen on anaerobic digestion in batch reactor. It was found that the entire anaerobic digestion process might exist an optimal initial concentration of inorganic nitrogen for methane gas production in the presence of calcium ions, magnesium ions and inorganic phosphorus.