Current Chinese Science - Volume 2, Issue 1, 2022

Catalysis is a multidisciplinary field involving areas of organometallic chemistry, material science and engineering. It finds use in the synthesis of various industrially applicable compounds, such as fuels and fine chemicals. The activity and selectivity are fundamental issues to be dealt with in catalysis, which are associated with the high surface area. Current research activities primarily deal with homogeneous and heterogeneous catalysis. Although homogeneous and heterogeneous catalysis have been well researched, they have certain drawbacks that need to be overthrown for their wider applications. Therefore, it is imperative to find a catalytic protocol that would lead to higher selectivity and exemplary product yield with quick and easy retrieval. Along with being an alternative to conventional bulk materials, nanomaterials have further established their caliber into various industrial and scientific applications. Nanocatalysis has emerged as an advanced substitute for conventional homogeneous and heterogeneous catalysis. The nanomaterials are accountable for intensifying the surface area of a catalyst, ultimately resulting in an increase in the catalyst reactants' contacts. Furthermore, it enacts as a robust component providing high surface area like a heterogeneous catalyst. Nanoparticles can be yielded out of a reaction medium due to their insoluble behaviour, and thus, as catalysts, they can be retracted easily from the product. Hence, it has been proven that nanocatalysts enact as both homogeneous and heterogeneous catalysts, functioning as a bridge between the conventional catalytic systems. Considering these merits, researchers have tried to intensively study the applications of nanocatalysts in numerous organic reactions. This review article focuses on the catalytic applications of metal nanoparticles (MNPs), such as Pd, Ag, Au, Cu, Pt, in ligand-free coupling reactions. Also, it covers the applications of bimetallic and multimetallic nanoparticles in ligand-free coupling reactions.

Background: A larger response delay of a high-speed solenoid valve will cause inaccurate fuel injection timing and imprecise cycle injection quantity, resulting in diesel engine emission and increased fuel consumption. Objective: Biodiesel as an ideal alternative fuel has exceptional advantages in energy conservation, emission reduction, and low-carbon environmental protection; however, matching with Electronic Unit Pump (EUP) and its impacts on solenoid valve operation need to be further studied. Methods: In the present work, a numerical model of EUP fueled with biodiesel was established in an AMESim environment, which was validated by the experiment. Then, combined with the Design of Experiments (DOE) method, key parameters influencing the solenoid valve response delay were predicted: armature residual air gap, spring preload, poppet valve half-angle, valve needle diameter, and poppet valve diameter. Results: taking the response delay time of solenoid valve as targets, multi-objective optimization model for high-speed solenoid valve was established using NSGA-II (non-dominated sorting genetic algorithm-II) genetic algorithm in modeFRONTIER platform. Conclusion: The optimized results showed that the delay time of the solenoid valve closing is reduced by 6%, the opening delay time is reduced by 20.8%, the injection pressure peak is increased by 1.8MPa, which is beneficial to accurate injection quantity and the application of biodiesel in diesel engines.

Background: The Environmental Management System (EMS) is a unique way to develop an environmental policy with adequate planning, including implementation, operation, checking, and management review. Objective: The main stages of the EMS encompass environmental policy, planning, implementation, evaluation, and review. Methods: A number of environmental standards (ISO 14000), which were drawn up by the international standardization organization, form an essential part of an EMS. This management system introduces environmental management into the day-to-day functions, long-term operations, and resource management frameworks of the organization. Results: This overview provides important information about the role of the EMS in water resource management and the scope of the EMS in the water system. This management system is used as an instrument to promote sustainable development in society. Conclusion: This paper sheds light on the topic of a sustainable water environment. In addition, some recognized successful EMS systems were reviewed and illustrated. We believe this review provides a guide to a fruitful water environment for successful urbanization planning.

Background: Amomum villosum is an important medicinal and edible plant owing to its valuable compositions of volatile and non-volatile compounds. Objective: The study was conducted to reveal the chemical constituents and medicinal values of A. villosum against various diseases. Methods: A critical and comprehensive data mining from 2004 to 2021 was performed based on CNKI, PubMed, and Google. Results: 120 Compounds have been reported collectively in seeds, peels, and rhizomes of A. villosum, 10 compounds were common however the content of bornyl acetate was maximum in seeds and peels. Similarly, Amomi fructus of China and Vietnam showed 59 different types of volatile compounds while 13 were common, the round large black fruits (1.56% bornyl acetate and 4.05% volatile oil) and long small red fruits type (1.64% bornyl acetate and 3.04% volatile oil) from China showed good quality and high medicinal values. In addition, Amomi fructus manifested 30-40 kinds of nonvolatile compounds, i.e., phenolic, polysaccharides, saponins, flavonoid, vanillic acid, catechin, epicatechin, polydatin, isoquercitrin, quercitrin, glycosides, inorganic and organic acids. Conclusion: A. villosum is widely used as anti-inflammatory, gastrointestinal protection, antiobesity, anticancer, antioxidant, analgesic, bacteriostasis, antidiabetic and anti-COVID-19, etc. So, it is manifested that the fruit, flowers, roots, stems, and leaves of A. villosum can be used as a medicine, especially fruit (Amomi fructus=Sharen), as the best functional food for the COVID-19 treatment and gastrointestinal protection as well as prevention of other diseases.

Objective: To investigate the risk factors of kidney calculi in its high prevalence areas of western Guangdong, and provide the proper prevention measures. Methods: A cross-sectional survey was conducted among individuals in Maoming, western Guangdong. Univariate and Poisson regression analyses were applied to investigate the influence of the epidemiology, lifestyle, and environmental factors on renal calculi. Risk ratios with 95% confidence interval were used to estimate the association between the investigated factors and the prevalence of renal calculi. Results: 500 questionnaires were sent out and 481 valid questionnaires were recycled. Among 481 respondents, 84 had renal calculi with a prevalence rate of 17.46%. Univariate regression analysis showed statistically significant differences in the prevalence of renal calculi among different groups of sex, ages, family history of kidney calculi, diet and drinking habit. Poisson regression analysis showed that daily water intake and drinking boiled water were protective factors, while male, family history of kidney calculi, diet high in protein, sugar, vitamin C and calcium were risk factors. Additionally, high sugar diet was not statistically significantly associated with the occurrence of renal calculi. Conclusion: The occurrence of kidney calculi in western Guangdong is closely related to demographic characteristics of individuals, living and dietary habits of the resident populations.

Background: Chronic Pancreatitis (CP) is a long-term risk factor for pancreatic ductal adenocarcinoma (PDAC), and both diseases share a common etiology. The activation of Pancreatic stellate cells (PaSCs) caused by inflammation of the chronic pancreas plays a pivotal role in the pathology of pancreatic fibrosis and the malignant phenotype of PDAC. However, the central role of activated PaSCs in Acinar-to-Ductal Metaplasia (ADM) remains unknown. Objective: In the present study, we investigated the link between pancreatic fibrosis and ADM and the possible underlying mechanism. Methods: A caerulein-treated mouse CP model was established, and Masson trichrome histochemical stain and Transmission Electron Microscope (TEM) were used to observe stromal fibrosis and cell ultrastructure, respectively. The expression of amylase and cytokeratin 19 (CK19), mitochondria respiration, and reactive oxygen species (ROS) were detected in vitro in the co-culture model of primary pancreatic acinar cells and PaSCs. Results: The activation of PaSCs and pancreatic fibrosis were accompanied by ADM in pancreatic parenchyma in caerulein-treated mice, which was verified by the co-cultivation experiment in vitro. Furthermore, we showed that activated PaSCs promote ADM by disrupting mitochondrial respiration and releasing ROS. The expression of inflammation-and ADM-related genes, including S100A8, S100A9, and CK19, was observed to be up-regulated in pancreatic acinar cells in the presence of activated PaSCs. The expression of S100A9 and CK19 proteins was also up-regulated in acinar cells co-cultured with activated PaSCs. Conclusion: The manipulation of mitochondrial respiration and ROS release is a promising preventive and/or therapeutic strategy for PDAC, and S100A9 is expected to be a therapeutic target to block the ADM process induced by the activation of PaSCs.