Photocatalytic Conversion of Lignin Models into Functionalized Aromatic Molecules Initiated by the Proton-Coupled Electron Transfer Process.

A mild and efficient method for lignin ß-O-4 cleavage and functionalization was achieved via photocatalysis. This protocol exhibits a broad scope of lignin models and excellent compatibility of functionalization reagents, constructing a series of functionalized lignin-based aromatic compounds. Highly selective formation of alkyl radical species through a proton-coupled electron transfer and ß-scission process provides the opportunity to form new C-C and C-N bonds by reaction with electrophilic reagents.

Diagnostic Imaging Analysis and Care of Patients with Endomyocardial Fibrosis Based on Wireless Network Smart Medical Application.

The heart is one of the most important organs of the human body, but in recent years heart disease has become one of the human health killers and this paper explores endomyocardial fibrosis, which is a common cardiomyopathy, commonly seen in infants and children, and refers to a diffuse elastic fibrous disease of the endocardium. The purpose of this paper is to explore the diagnostic imaging analysis and care of patients with endocardial heart machine fibrosis using wireless network intelligent medical technology, aiming to provide a new power basis for the treatment of the disease in related patients. This paper proposes a new endocardial segmentation algorithm that aims to process image information using image features, intervene in image noise reduction and smoothing, etc., and use image grayscale values to confirm cardiac cavity grayscale values as a basis for physicians to make certain judgments for the diagnosis of patients with endocardial machine fibrosis. The experimental results show that the atrial fibrillation group is distinctly higher compared to the sinus rhythm group, with values remaining between 25 and 39, which is a significant advantage compared to other methods.

Stochastic fuzzy environmental risk characterization of uncertainty and variability in risk assessments: A case study of polycyclic aromatic hydrocarbons in soil at a petroleum-contaminated site in China.

Better decisions are made using risk assessment models when uncertainty and variability are explicitly acknowledged. Uncertainty caused by a lack of uniform and scientifically supported environmental quality guidelines and variability in the degree of exposure of environmental systems to contaminants are here incorporated in a stochastic fuzzy environmental risk characterization (SFERC) approach. The approach is based on quotient probability distribution and environmental risk level fuzzy membership function methods. The SFERC framework was used to characterize the environmental risks posed by 16 priority polycyclic aromatic hydrocarbons (PAHs) in soil at a typical petroleum-contaminated site in China. This relied on integrating data from the literature and field and laboratory experiments. The environmental risk levels posed by the PAHs under four risk scenarios were determined using the SFERC approach, using "residential land" and "industrial land" environmental quality guidelines under "loose" and "strict" strictness parameters. The results showed that environmental risks posed by PAHs in soil are primarily caused by oil exploitation, traffic emissions, and coal combustion. The SFERC approach is an effective tool for characterizing uncertainty and variability in environmental risk assessments and for managing contaminated sites.

[Identification of vibration characteristics in infrared spectrum of polybrominated diphenyl ethers congeners based on Br substituents].

Structure optimization and frequency calculations of 209 kinds of PBDEs homologues were carried out at the B3LYP/6-31G(d) level based on density functional theory, the known experimental parameters of 4 PBDEs congeners were compared with the calculated values, and the average analog coefficient was 0. 989. The main vibration of DE and BDE-209 which contained only H atoms or Br substituent in the benzene ring was assigned due to their less interference for various infrared spectrum vibrations. C-Br bond vibration which was often coupled with other forms of vibration was not easy to distinguish between PBDEs congeners. With the characteristics of universality, strong vibration and identifiable, triangular breathing vibration of the benzene rings in the infrared spectrum was selected as a characteristic vibration among different PBDEs homologues, the analysis results showed that the ortho-substituted and para-substituted Br could significantly improve the vibration frequency of triangular breathing vibration, while the meta-substituted Br played the opposite role; For the low bromide, the more the substituents in ortho position, the higher the frequency, while for the high bromide homologues, simultaneous existence in ortho-position and para-position would have a higher frequency; With the same substituted location, the more the substituent in the same benzene ring, the higher the vibration frequency. SVM regression model was used to verify the relative relationship between Br substituent and triangle breathing vibration frequency of the benzene rings, and the simulation efficiency coefficient of model was 0. 956. The study provided a theoretical basis and guidance for actually testing and identifying PBDEs homologues in the environment.

A dynamic multimedia fuzzy-stochastic integrated environmental risk assessment approach for contaminated sites management.

A dynamic multimedia fuzzy-stochastic integrated environmental risk assessment approach was developed for contaminated sites management. The contaminant concentrations were simulated by a validated interval dynamic multimedia fugacity model, and different guideline values for the same contaminant were represented as a fuzzy environmental guideline. Then, the probability of violating environmental guideline (Pv) can be determined by comparison between the modeled concentrations and the fuzzy environmental guideline, and the constructed relationship between the Pvs and environmental risk levels was used to assess the environmental risk level. The developed approach was applied to assess the integrated environmental risk at a case study site in China, simulated from 1985 to 2020. Four scenarios were analyzed, including "residential land" and "industrial land" environmental guidelines under "strict" and "loose" strictness. It was found that PAH concentrations will increase steadily over time, with soil found to be the dominant sink. Source emission in soil was the leading input and atmospheric sedimentation was the dominant transfer process. The integrated environmental risks primarily resulted from petroleum spills and coke ovens, while the soil environmental risks came from coal combustion. The developed approach offers an effective tool for quantifying variability and uncertainty in the dynamic multimedia integrated environmental risk assessment and the contaminated site management.