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The use of digital image correlation for modal analysis is becoming an appealing option thanks to its non-contact and full-field measurement process. However, frequency response function (FRF) estimation can be challenging due to the limited number of time domain data and heavy measurement noise. Thereby, the present work aims to propose a method which improves the estimation accuracy of point-wise FRFs. Firstly, a Gaussian-process-based spatial-frequency model is proposed, which makes use of the intrinsic properties of the FRF and the local spatial information of field measurements. Then, a Bayesian solution is developed, which is enforced by a stable and efficient numerical procedure. Finally, the effectiveness of the proposed method is verified by making a comparison with the spectral estimator through the use of simulated data, and it is further validated based on an experimental application.

Spherical quantum wells (SQWs) have proven to be excellent materials for suppressing Auger recombination due to their expanded confinement volume. However, research on the factors and mechanisms of their high-intensity optical properties, such as multiexciton properties and third-order optical nonlinearities, remains incomplete, limiting further optimization of these properties. Here, a series of CdS/CdSe (xML)/CdS SQWs with varying CdSe layer thicknesses were prepared. The modulation effects of CdSe shell variations on the PL properties, defect distribution, biexciton binding energy, and third-order optical nonlinearities of the SQWs were investigated, and their impact on the material’s multiexciton properties was further analyzed. Results showed that the typical CdS/CdSe(3ML)/CdS sample exhibited a large volume-normalized two-photon absorption cross-section (18.17 × 102 GM/nm3) and favorable biexciton characteristics. Optical amplification was observed at 12.4 μJ/cm2 and 1.02 mJ/cm2 under one-photon (400 nm) and two-photon (800 nm) excitation, respectively. Furthermore, different amplified spontaneous emission spectra were observed for the first time under one/two-photon excitation. This phenomenon was attributed to thermal effects overcoming the biexciton binding energy. This study provides valuable insights for further optimizing multiexciton gain characteristics in SQWs and developing optical gain applications.

The screening and identification of drug metabolites in biological matrices is challenging, and ultra-high performance liquid chromatography-Q-Exactive Orbitrap mass spectrometry (UHPLC-Q-Exactive Orbitrap MS) has become a powerful technological tool for drug metabolites analysis due to its high sensitivity. However, the spectral information contained in existing chemical standards and databases is very limited, and the UHPLC-Q-Exactive Orbitrap MS technique alone cannot satisfy the identification of complex and diverse metabolites. Therefore, there is an urgent need for a new strategy to achieve comprehensive drug metabolic profile. Based on this, we have innovatively constructed a “recursive tree” analysis strategy and bridged it with network pharmacology for elucidating the pharmacological mechanisms of drugs. In this paper, we investigated the overall metabolic profile of formononetin as an example and utilized the primary branching metabolites of formononetin as effective ingredients for the study of the anti-NAFLD mechanism. The results showed that a total of 131 metabolites (prototype drug included) were detected and identified. Among them, 106 metabolites were found in rats and 31 metabolites were found in liver microsomes. Glucose conjugation, demethylation, sulfation, glucuronidation, and their complex reactions were the major processes of formononetin biotransformation. Network pharmacology results screened 104 potential targets and 20 major signaling pathways. Their mechanisms may be additive and/or synergistic effects. In addition, the therapeutic effects of formononetin against NAFLD were investigated based on palmitic acid / oleic acid-induced HepG2 cells. In summary, the recursive tree analysis strategy provides a convenient method for the identification of metabolites, and its seamless integration with network pharmacology lays the foundation for studying the pharmacological activities of natural products.

Both phloretin and phlorizin (phloretin 2′-O-glucoside) extracted from the peel of apples are attributed to particular flavonoid dihydrochalcones with multiple pharmacological activities. However, metabolite structural characterization of these two components, which may accumulate to exert their pharmacological effects, remains insufficient. The present study aimed to comparatively clarify the metabolic pathways of phloretin and phlorizin after oral administration individually to Sprague-Dawley (SD) rats. Therefore, a rapid, integrate and systematic analytical strategy based on characteristic fragment ion fishing was proposed for the screening and identification of metabolites coming from phloretin and phlorizin using UHPLC-Q-Exactive Orbitrap mass spectrometry in parallel reaction monitoring mode. As a result, a total of 50 phloretin metabolites and 52 phlorizin metabolites were individually identified from different biological samples including rat plasma, urine, and faeces. Moreover, glucuronidation, sulfation, carbonylation and hydrolyzation were revealed to be the main metabolic pathways of phlorizin, while decarbonylation, glucuronidation and sulfation were regarded as the predominant biotransformation pathways as for phloretin. This is the first systematic study on comparison of metabolic profiles of phlorizin and phloretin in disease states, which was helpful to declare the complicated structure activity relationships between phlorizin and phloretin and shed light to their action mechanism.

The self-assembled structures of coix seeds affected the enzymatic efficiency and doesn‘t facilitate the release of more active peptides. The influence of heating combined with ultrasound pretreatment (HT + US) on the structure, enzymatic properties and hydrolysates (CHPs) of coix seed prolamin was investigated. Results showed that the structural of coix seed prolamins has changed after HT + US, including increased surface hydrophobicity, reduced α-helix and random coil content, and a decrease in particle size. So that, leads to changes in thermodynamic parameters such as an increase in the reaction rate constant and a decrease in activation energy, enthalpy and enthalpy. The fractions of

Radix Astragali (RA) is used as a traditional spice and food additive, and it is also rich in isoflavone glycosides, including calycosin-7-O-glucoside, ononin and genistin, which have beneficial effects against inflammation and oxidative stress. However, most isoflavone glycosides are hydrolyzed to other metabolites by intestinal bacteria before absorbed into the body. In this study, the levels of the above three isoflavone glycosides and their aglycones in 12 RAs from different regions were analyzed by high performance liquid chromatograph (HPLC). Then, the metabolites of the three isoflavone glycosides transformed by human feces at different times were quantified by HPLC and identified by ultra-high performance liquid chromatograph coupled with high resolution mass spectrometer (UHPLC-HRMS) and nuclear magnetic resonance hydrogen spectrum (1H-NMR). Furthermore, the anti-inflammatory and antioxidant activities of the metabolites were evaluated and the possible mechanism was analyzed by network pharmacology. As a result, a total of 18 metabolites were identified and the metabolic profiles were constructed. Among them, 4 metabolites, including 3′,4′,7-trihydroxyisoflavone, pratensein, dihydrogenistein and daidzein, were separated and identified, of which the metabolic process of pratensein was discovered for the first time. The anti-inflammatory and antioxidant activity results and network pharmacology analysis showed that there was a close relationship between the activities and the metabolic profiles, especially the formation of aglycones. This study is of significance to reveal the metabolic process of the isoflavones of RA in the intestine, and also provides guidance for the metabolism of other flavonoid glycosides.

Narirutin, extracted from the dried ripe pericarp of Rutaceae orange and its cultivated varieties, is a dihydroflavone compound with various biological activities and pharmacological effects. So far as we know, the metabolism profiling of narirutin has been insufficient until now. In the present study, an efficient method was employed to perform rapid analysis and identification of narirutin metabolites by using ultra-high performance liquid chromatography quadrupole exactive orbitrap MS/MS (UHPLC-Q-Exactive Orbitrap MS/MS) combined with an analogous core recursion (ACR) analysis strategy. Firstly, according to the basic core structure of the dihydroflavonoid, the cleavage mode and fragmentation ions of narirutin were summarized. Secondly, based on the difference of the substituent groups, the fragment ions of narirutin were preliminarily inferred and verified by the secondary mass spectra of its standard compound. Thirdly, the fragment ions of narirutin in positive and negative ion modes were summarized to provide a basis for the identification of metabolites. Fourthly, candidate metabolites were accurately and tentatively identified according to the cleavage law of mass spectrometry, literature reports, comparison of reference substances, and especially the diagnostic fragment ion clusters (DFICs) and characteristic suggestive ions (CSIs) deduced preliminarily. Finally, a total of 46 metabolites (30 in vivo and 19 in vitro), including prototype drugs were identified based on the ACR analysis strategy, chromatographic retention behavior of metabolites, corresponding ClogP value and accurate molecular weight. Among them, 22 metabolites were discovered in rats plasma, 12 in urine, 4 in liver tissue, 19 in liver microsomes, respectively. Additionally, metabolites relative contents were also studied by extracted ion chromatography (EIC) method. Our result also illustrated that narirutin primarily underwent glucuronidation, sulfation, glutathione binding, deglycosylation, oxidation, reduction, methylation, hydroxylation, ring-opening and their composite reactions. A novel strategy was constructed to comprehensively elucidate the biotransformation pathways of narirutin in vitro and in vivo, and a systematic metabolic profile of narirutin was generated. This study provided a great reference for further understanding of the biotransformation pathways and guiding for clinical application of narirutin.

This study proposes a terahertz metamaterial structure composed of a silicon–graphene–silicon sandwich, aiming to achieve quadruple plasmon-induced transparency (PIT). This phenomenon arises from the interaction coupling of bright–dark modes within the structure. The results obtained from the coupled mode theory (CMT) calculations align with the simulations ones using the finite difference time domain (FDTD) method. Based on the electric field distributions at the resonant frequencies of the five bright modes, it is found that the energy localizations of the original five bright modes undergo diffusion and transfer under the influence of the dark mode. Additionally, the impact of the Fermi level of graphene on the transmission spectrum is discussed. The results reveal that the modulation depths (MDs) of 94.0%, 92.48%, 93.54%, 96.54%, 97.51%, 92.86%, 94.82%, and 88.20%, with corresponding insertion losses (ILs) of 0.52 dB, 0.98 dB, 1.37 dB, 0.70 dB, 0.43 dB, 0.63 dB, 0.16 dB, and 0.17 dB at the specific frequencies, are obtained, achieving multiple switching effects. This model holds significant potential for applications in versatile modulators and optical switches in the terahertz range.

Neomangiferin (NMF) is an extremely special xanthone that could be simultaneously attributed to C-glycoside and O-glycoside with a variety of biological activities, such as anti-inflammatory, antitumor, antipyretic, and so on. So far as we know, the metabolism profiling has been insufficient until now. Herein, Drug Metabolite Cluster Centers (DMCCs)-based Strategy has been developed to profile the NMF metabolites in vivo and in vitro. Firstly, the DMCCs was proposed depending on literature-related and preliminary analysis results. Secondly, the specific metabolic rule was implemented to screen the metabolites of candidate DMCCs from the acquired Ultra High Performance Liquid Chromatography Quadrupole Exactive Orbitrap Mass Spectrometry (UHPLC-Q-Exactive Orbitrap MS) data by extracted ion chromatography (EIC) method. Thirdly, candidate metabolites were accurately and tentatively identified according to the pyrolysis law of mass spectrometry, literature reports, comparison of reference substances, and especially the diagnostic product ions (DPIs) deduced preliminarily. Finally, network pharmacology was adopted to elucidate the anti-inflammatory action mechanism of NMF on the basis of DMCCs. As a result, 3 critical metabolites including NMF, Mangiferin (MF) and Norathyriol (NA) were proposed as DMCCs, and a total of 61 NMF metabolites (NMF included) were finally screened and characterized coupled with 3 different biological sample preparation methods including solid phase extraction (SPE), acetonitrile precipitation and methanol precipitation. Among them, 32 metabolites were discovered in rat urine, 30 in rat plasma, 12 in rat liver, 9 metabolites in liver microsomes and 8 in rat faeces, respectively. Our results also illustrated that NMF primarily underwent deglucosylation, glucuronidation, methylation, sulfation, dihydroxylation and their composite reactions in vivo and in vitro. Additionally, network pharmacology analysis based on DMCCs revealed 85 common targets of disease-metabolites, and the key targets were TNF, EGFR, ESR1, PTGS2, HIF1A, IL-2, PRKCA and PRKCB. They exerted anti-inflammatory effects mainly through the pathways of inflammatory response, calcium-dependent protein kinase C activity, nitrogen metabolism, pathways in cancer and so on. In general, our study constructed a novel strategy to comprehensive elucidate the biotransformation pathways of NMF in vivo and in vitro, and provided vital reference for further understanding its anti-inflammatory action mechanism. Moreover, the established strategy could be generalized to the metabolism and action mechanism study of other natural products.

Ethnopharmacological relevance: Metabolic syndrome is closely related to the intestinal microbiota and disturbances in the host metabolome. Hyperuricemia (HUA), a manifestation of metabolic syndrome, can induce various cardiovascular diseases and gout, seriously affecting a patient’s quality of life. Astragalus membranaceus has a long history as a commonly used traditional Chinese medicine to treat kidney disease in China and East Asia. Materials and methods: We compared the therapeutic effect of benzbromarone and two different doses Astragalus membranaceus ultrafine powder (AMUP) in rats with HUA. Ultra-performance liquid chromatography-mass spectrometer was used to analyze the AMUP metabolism in the plasma, urine, and feces. Further, 16S ribosome RNA sequencing and feces metabolomic were performed to capture the variation of the gut microbiota and metabolites changes before and after drug administration. Results: AMUP had a notable impact on reducing blood uric acid levels while protecting the liver and kidney. Drug metabolism analysis demonstrated that effective constituent flavonoids are distributed in the blood, whereas saponins remain in the intestine. Gut microbiota analysis showed that low-dose AMUP ameliorated HUA-induced gut dysbiosis by reducing the abundance of harmful bacteria and increasing that of some beneficial bacteria with anti-inflammatory properties, such as Clostridia, Lachnospiraceae, and Muribaculaceae. In addition, HUA-induced changes in metabolite contents in bile acid and adrenal hormone biosynthesis pathways were restored after treatment with AMUP. Conclusion: Low-dose AMUP exerts remarkable therapeutic effects on HUA by regulating the gut microbiome and mediating gut metabolism pathways associated with uric acid excretion.

Cardamonin is a chalcone that presents at high content in the seeds of Alpinia katsumadai Hayata. In recent decades, researchers have found that it is not only an edible spice, but also a remarkable herb with a wide range of pharmacological properties. However, its specific metabolic routes in vivo remain unclear while these metabolites may accumulate to exert pharmacological effects. Our study aimed to clarify the metabolic pathways of cardamonin after oral administration to rats. Here, an advanced UHPLC-Q-Exactive Orbitrap MS analytical technique was applied for efficient detection of metabolites in vivo, which especially showed benefits in obtainment of the fragment ions with relatively lower contents. We also established a novel strategy to identify metabolites based on typical fragmentation routes. The results indicated that a total of 40 metabolites could be categorized into 3 types with consideration of the particular structures and characteristic fragment ions. Then, diagnostic product ions (DPIs) of each type were summarized for further screening and identification of metabolites derived from cardamonin. Finally, methylation, demethylation, hydrogenation, hydroxylation, dehydroxylation, glucuronidation and sulfation were confirmed to be the major metabolic pathways in vivo. Our observation extended the metabolic mechanism of cardamonin and could be of great benefits to interpreting the action mechanism of cardamonin in vivo.

The selective functionalization of C(sp3)–H bonds via intramolecular amination reactions represents a very attractive strategy for the construction of saturated N-containing heterocycles (SNHets). Over the past de- cades, the chemical community has devoted its efforts towards expanding the synthetic toolbox with the aim of facilitating access to these key fragments in a controllable, reproducible and efficient manner. This review covers selected examples of the most recent advances in intramolecular C(sp3)–N bond-forming reactions by three main approaches: (1) the Hofmann-Löffler-Freytag (HLF) reaction; (2) transition-metal-catalyzed nitrene C(sp3)–H inser- tion; and (3) transition-metal-catalyzed ligand-assisted C(sp3)–N bond-forming reactions via a reductive elimination step. We will discuss reactivity, selectivity and the major mechanistic insights into these transformations.

Resveratrol is an antitoxin secreted by plants such as Polygonum cuspidatum Sieb. et Zucc and Vitis vinifera L. when they are attacked by pathogens. In the present study, three methods were used to prepare biological samples, and then an efficient strategy based on ultra-high-performance liquid chromatography-linear ion trap-Orbitrap mass spectrometry (UHPLC-LTQ-Orbitrap MS) was developed to screen and identify resveratrol metabolites in rat urine, plasma and faeces. As a result, a total of 56 resveratrol metabolites were screened and characterized. Among them, 39 metabolites were found in rat urine, while 6 and 16 metabolites were characterized from rat plasma and faeces, respectively. In addition, 56, 12 and 15 metabolic products were screened by solid phase extraction (method I), methanol precipitation (method II) and acetonitrile precipitation (method III), respectively, indicating that method I could be adopted as the most acceptable method. The results also demonstrated that resveratrol mainly underwent glucuronidation, glucosylation, sulfation, hydroxylation, dehydrogenation, hydrogenation, methylation and their composite reactions. Moreover, these metabolic reactions occurred to form a possible metabolic network that is similar to a triangular pyramid model. In summary, this research provides an idea for the further study of drug metabolism.

Studies on herbal medicines and fermentation products have become increasingly essential with the development of modern industry and technology. In order to verify that fermentation can bring about changes, Paecilomyces cicadae [Paecilomyces cicadae (Miquel.) Samson] was used to ferment Astragali radix [Astragalus membranaceus (Fisch.) Bge. var. mongho-licus (Bge.) Hsiao]. After solid fermentation for Astragali radix produced by Paecilomyces cicadae (SF-AP) was established, an efficient strategy based on ultra-high performance liquid chromatography-linear ion trap-Orbitrap mass spectrometry (UHPLC-LTQ-Orbitrap MS) was developed to screen and identify the chemical transformations in SF-AP and Astragali radix according to the acquired diagnostic product ions (DPIs). As a result, 114 compounds including 45 saponins and 69 flavonoids were finally identified and validated. Moreover, two kinds of antioxidative tests corresponding to the scavenging of DPPH· and ABTS·+ were applied to evaluate the antioxidative activity of Astragali radix before and after fermentation. The results demonstrated that some significant chemical transformations such as relative content fluctuations and structural isomerism owing to the occurrence of hydrolysis and conversion reactions and the antioxidative activity of SF-AP was much higher than that of the Astragali radix. This study could provide a new method for the utilization of Astragali radix and constructive guidance for the further research of fermented herbal medicines.

Drinking water containing a high amount of ammonium-nitrogen (NH4+-N) is not effectively removed by conventional treatment processes and can cause eutrophication. In this research, a composite adsorbent based on chitosan crosslink with zeolite molecular sieve (CTS-ZMS) was prepared for NH4+-N removal through dynamic adsorption filter experiments. Effect of bed depth (30, 50 and 70 cm), flow rate (32, 49 and 65 mL/min), initial pH value (4.5, 6.5 and 8.5) and influent NH4+-N concentration (3, 5 and 7 mg/L) was examined by using a filter column packed with CTS-ZMS particles. The Thomas model was applied to study the breakthrough curves and adsorption capacity. The optimal process parameters of the aforementioned factors were obtained at bed depth of 70 cm, flow rate of 32 mL/min, pH of 6.5 and initial NH4+-N concentration of 7 mg/L. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and Fourier Transform Infrared Spectroscopy (FTIR) were investigated to analyze the structure and morphology of the CTS-ZMS adsorbents before and after 3 months running. The EDS and FTIR results showed Na+ and the active functional groups of -OH, -NH2 and -COO− on CTS-ZMS adsorbent particles reacted with ammonium nitrogen. The results of this study supported the use of CTS-ZMS to improve drinking water filtration processes by increasing ammonium nitrogen reductions.