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Saponins are the main active components in Panax ginseng C. A. Mey. (PG), Panax quinquefolius L. (PQ), and Panax japonicus C. A. Mey. (PJ), which belong to the genus Panax in the Araliaceae family. Because the chemical components in the three species are similar, they are often mixed and misused in functional foods and pharmaceuticals applications. Therefore, it is urgent to establish a method to quickly distinguish among PG, PQ, and PJ. Ultraperformance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS) was combined with data postprocessing to identify the main characteristic fragments (CFs) and the related neutral losses (NLs) of protopanaxadiol (PPD), protopanaxatriol (PPT), oleanolic acid (OLE), and ocotillol- (OCO-) type saponins. By comparing the mass spectral data, it was possible to rapidly classify and identify saponins in PG, PQ, and PJ. A total of twenty-three chemical components were identified in the PG samples, twenty-three components were identified in the PQ samples, and twenty-seven components were identified in the PJ samples. Among them, OCO-type saponins were characteristic of PQ and PJ. Ginsenoside Rf, which was absent from PQ, allowed for differentiation between PQ and PJ. The CFs and NLs in the mass spectra of the characteristic components of PG, PQ, and PJ allowed for the rapid classification and identification of these species. Additionally, these results provide technical support for the quality evaluation of Chinese herbal medicine and for constructing a scientific regulatory system.

This paper presents an improved trajectory tracking controller based backstepping control algorithm to address the trajectory tracking problem of an underactuated Unmanned Surface Vessel (USV). A Three Degree of Freedom (DOF) underactuated maneuvering motion model for water-jet-propelled USV is established, and controller can track both straight line trajectory and curve trajectory with relatively high accuracy. The stability of USV system is proved by BIBO (bounded-input-bounded-output stable) characteristics, then simulation experiments are carried out to demonstrate the robustness and precise control performance of the controller.

Halophyte-based desalinization is emerging as a promising technology for saline agriculture. However, few studies have integrated halophytes into intercropping systems. This study investigated Suaeda salsa and soybean intercropping and the associated mechanisms, including changes in salt, nutrients, and bacterial communities at three salt treatments (control, 3‰, and 5‰). The results showed that regardless of salt treatment, soybean biomass and P content significantly increased in intercropping compared with monocropping, by an average of 32% and 51%, respectively (p < 0.05), indicating interspecific facilitation. Under 5‰ salt, soybean mortality decreased from 37% in monocropping to 10% in intercropping, and shoot Na decreased by over 60% in intercropping; the rhizosphere Na+, Cl−, and NO3−–N decreased in intercropping by over 75% compared with monocropping, and the response ratios correlated negatively with S. salsa biomass (p < 0.01). The soybean rhizosphere bacterial community in intercropping was enriched with the genera Sphingomonas, Salinimicrobium, Lysobacter, Allorhizobium–Neorhizobium–Pararhizobium–Rhizobium, and Ramlibacter, and the bacterial co-occurrence network exhibited increases in the number of nodes and edges, average degree, and average clustering coefficient. Considering the combined effects, the soybean biomass of intercropping correlated positively with bacterial co-occurrence network parameters, including average degree and number of edges, independent of tissue salt and nutrient content, and that of monocropping correlated negatively with tissue salt content. These results demonstrate that S. salsa intercropping could alleviate salt stress in soybean by creating a low-salt environment and improving its nutrient accumulation and rhizosphere bacterial community, and emphasize the importance of microbial communities in influencing soybean growth. [ABSTRACT FROM AUTHOR]

In light of the small ring strain of five/six-membered cyclic ethers, constructing complex molecules via ring-opening reactions has consistently been a highly challenging topic in organic synthesis. Induced by Lewis acids, the charge redistribution in cyclic ethers forms oxonium ylide intermediates, thereby activating the C–O bond and subsequently facilitating nucleophilic attack for ring opening. In recent years, a variety of novel Lewis acids, encompassing those with new metal centers and frustrated Lewis pairs (FLPs), have been effectively utilized to induce the formation of oxonium ylides, offering a diverse array of methods for the ring opening of five/six-membered cyclic ethers. This review conveys the extensive application advancements of diverse Lewis acid types for cyclic ether ring-opening reactions over the past two decades, originating from the perspective of the classification of Lewis acids. Furthermore, the substrate applicability and chemical transformation efficiency of these Lewis acids in the ring-opening reactions of cyclic ethers have also been discussed herein. [ABSTRACT FROM AUTHOR]

Ternary copolymerization is a cost‐effective and time‐saving approach to improve device performance and batch stability of polymer donors. However, the structure of the ternary polymer donor obtained by the traditional one‐pot polymerization is vague due to the different monomer reaction order, which has a great influence on the absorption, crystallization, molecular stacking, and device performance. Therefore, it is necessary to obtain terpolymers with definite structures, and systematically study the differences in device properties of polymers with different sequence structures. Herein, three terpolymers D1, D2, and D3 are developed. Random copolymer D3 is obtained via the traditional one‐pot method while alternating copolymer donor D1 and block copolymer D2 are synthesized by stepwise polymerization. Because the block copolymer D2 possess periodic sequence distribution and retains the excellent properties of the two polymer matrix very well, the D2‐based device shows enhanced tightened π‐face‐on molecular stacking, distinguished efficient exciton dissociation, and decreased energy loss. As a result, the D2:L8‐BO‐based polymer solar cells achieve one of a record power conversion efficiency of 19.03%. The work demonstrates changing the sequence structure of the polymers to synthesize well‐defined structures polymer donors not only maintains the features of polymer matrix, but also combines the advantages of ternary copolymerization. [ABSTRACT FROM AUTHOR]