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In the paper, we study the non-Hermitian system under dissipation and give the effective 2 × 2 Hamiltonian in the k-space by reducing the N × N Hamiltonian in the real space for them. It is discovered that the energy band shows an imaginary line gap. To describe these phenomena, we propose the theory of “non-Hermitian tearing” , in which the tearability we define reveals a continuous phase transition at the exceptional point. The non-Hermitian tearing manifests in two forms — separation of bulk state and decoupling of boundary state. In addition, we also explore the one-dimensional Su–Schrieffer–Heeger model and the Qi–Wu–Zhang model under dissipation using the theory of non-Hermitian tearing. Our results provide a theoretical approach for exploring the controlling of non-Hermitian physics on topological quantum states. [ABSTRACT FROM AUTHOR]

A novel organic base-assisted (OB-assisted) mechanochemical extraction (MCE) method was established for the efficient extraction of water- and fat-soluble compounds from Ophiopogon japonicus. This study investigated the influence of OB type, amount of OB, grinding time, solid-liquid ratio, vortexing time, and pH. The optimal conditions obtained from the response surface methodology are 124.16 μL of n-butylamine, a grinding time of 6.06 min, and pH of 10.59. In addition, the method showed a good linear relationship (R2 > 0.99), high accuracy (relative standard deviation > 4.44%), and an acceptable recovery rate (89.99–110.52%). The results of scanning electron microscopy suggested that mechanochemical processes may destroy the cell walls and convert the target compounds into water-soluble salt forms in the presence of added OBs. Compared with other methods, the proposed MCE does not use any organic solvent in the extraction medium and reduces the extraction time. It was successfully applied to extract flavonoids and saponins from Ophiopogon japonicus. [Display omitted] • A novel organic base-assisted mechanochemical extraction method was established. • Water is used as a solvent, and no organic solvents are used. • The method can extract hydrophobic and hydrophilic compounds at the same time. • This method can be applied to complex matrixes. • It is an efficient, green and environmentally friendly method. [ABSTRACT FROM AUTHOR]

[Display omitted] • The one-step admicelle to cyclodextrin sweeping method was established. • The approach was applied in the preconcentration of five toxic aristolochic acids. • The method showed low detection limit with 3–6 ng/mL. • The sensitivity enrichment factors of five aristolochic acids was enhanced to 30–68. One-step admicelle to cyclodextrin sweeping (ACDS) method in capillary electrophoresis (CE) has been developed for the separation and preconcentration of toxic aristolochic acids (AAs) by applying cetyltrimethylammonium chloride (CTAC) between the critical micelle concentration and critical surface aggregation concentration. The analytes were captured into the CTAC admicelles, after the more stable inclusion complexes were formed, the release and preconcentration of the analytes could be realized. The CE enrichment parameters, such as the types of cationic surfactants and cyclodextrins (CDs), the concentration of cationic surfactants, disodium tetraborate decahydrate (borax) and CDs, the volume ratio of acetonitrile (ACN) in background electrolyte (BGE) and the sample injection time were optimized systemically. The optimal BGE was composed of 20 mM borax, 10 mM γ-CD and 10 % (v/v) ACN, the sample matrix consisted of 0.2 mM CTAC, 20 mM borax and five analytes. The limit of detection of this method was 3–6 ng/mL, and good linearity values (R2) were obtained for five AAs in the range of 0.997–0.999. Applying optimized conditions, the enrichment efficiencies of five AAs were enhanced with the sensitivity enrichment factors of 30–68. The sweeping approach was successfully applied to the determination of A, B, Ⅶ a , C and D in Aristolochia and Asarum samples, which could provide a potential in the enrichment of the other toxic compounds. [ABSTRACT FROM AUTHOR]

[Display omitted] • Multiple pesticides were accurately determined by SFC-IM-Q-TOF/MS. • Single- and multifield CCS values were examined as highly specific parameters. • Mass fragments elucidated the regularities of structure and characteristic ions. • The method was successfully applied to potatoes and yams with excellent results. • The developed method is efficient, green and highly sensitive. This experiment aimed to establish a green, simple and highly sensitive method (supercritical fluid chromatography (SFC) coupled with ion mobility quadrupole time-of-flight mass spectrometry (IM-Q-TOF/MS)) for the detection of multiple pesticides in foods. During the experiments, several important SFC parameters, such as stationary phase, modifier, make-up solution, back-temperature and back-pressure were optimized. Here, single-field collision cross section (CCS) values and multifield CCS values of 20 pesticides were examined by IM-Q-TOF/MS as highly specific parameters with excellent experimental precision. In addition, based on accurate mass matching and fragment ion comparison, mass fragments were obtained by IM-Q-TOF/MS, which elucidated the regularities of compound structure and characteristic fragment ions. Under the optimized conditions, satisfactory linearity (R2 ≥ 0.9989) and recoveries (79.60 % to 112.97 %) were obtained. The intra- and interday precisions were favorable, with RSDs lower than 4.91 and 7.65 %, respectively. Additionally, the method showed low limits of detection (0.1–8.8 ng/mL). The proposed method has been successfully applied to the highly sensitive detection of phenylurea herbicide, triazine herbicides, organophosphorus pesticide, pyrethroid insecticide and acaricide in yam and potato. [ABSTRACT FROM AUTHOR]

A simple and efficient visible‐light‐initiated cascade reaction of 2‐isothiocyanatonaphthalenes and amines with ambient dioxygen as the sole oxidant under additive‐, external photocatalyst‐free and ambient conditions was developed. 38 Examples of N‐substituted naphtho[2,1‐d]thiazol‐2‐amines were regioselectively constructed in good to excellent yields. [ABSTRACT FROM AUTHOR]

HMG-CoA reductase (HMGCR) is the rate-limiting enzyme in cholesterol de novo biosynthesis and its degradation may bring therapeutic benefits for the treatment of cardiovascular disease (CVD) and nonalcoholic steatohepatitis (NASH). Before, we disclosed compound HMG499 as a potent HMGCR degrader, which could be a promising agent for treating CVD, however its side-effect of promoting cholesterol accumulation in cells should be eliminated before progression. Herein, a series of novel heterocyclic ring-fused analogs of HMG499 were synthesized and investigated for their activities of stimulating HMGCR degradation using a HMGCR (TM1-8)-GFP reporting system. Among them, the most active compound 29 (QH536) showed an EC 50 of 0.22 μΜ in promoting HMGCR degradation, which was about 2 times more potent than HMG499 (EC 50 = 0.43 μM). Interestingly, 29 was different from HMG499, it had no side-effect of inducing cholesterol accumulation in cells. Mechanistic studies disclosed that 29 could significantly decrease statin-induced accumulation of HMGCR protein via ubiquitination and degradation of HMGCR through ubiquitin-proteasome pathway and inhibit the cholesterol biosynthesis in cells. Therefore, these heterocyclic ring-fused analogs could be used as promising leads for the development of new types of agents against CVD. Furthermore, 29 also lowered cholesterol levels and suppressed TGFβ1-induced proliferation of LX-2 hepatic stellate cells in a dose-dependent manner. In particular, 29 not only decreased the NASH associated fibrotic mRNA and protein expression of α-SMA, COL1A1, TIMP1 and TGFβ1 but also suppressed cholesterol levels and inflammatory genes of TNF-α, IL-6 an IL-1β in RAW264.7 macrophage cells, indicating that 29 may bring therapeutic benefit to treat NASH. A series of heterocyclic ring-fused analogs of HMG499 were synthesized and their activities of promoting HMG-CoA reductase degradation and side-effects of inducing cholesterol accumulation in cells were evaluated. [Display omitted] • A series of novel heterocyclic ring-fused analogs of HMG499 were synthesized. • The activities of promoting HMGCR degradation of these analogs were evaluated. • Compound 29 is the most potent HMGCR degrader. • Compound 29 possessed no side-effect of inducing cholesterol accumulation. [ABSTRACT FROM AUTHOR]