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The energy management optimization and DC voltage stability are the main challenges when loads surging and renewable energy sources (RESs) fluctuations occur in the medium-voltage DC distribution system (MVDC-DS). To solve these issues, this paper proposes a dual-time scale energy management method based on improved droop control for the MVDC-DS. Firstly, a ±10 kV three-terminal hybrid modular multilevel converter (MMC)-based ring MVDC-DS with DC fault ride-through capability is constructed, which including electric vehicle charging stations, energy storage systems, multiple loads and RESs. Secondly, the droop control adopted by the hybrid MMC is improved by exp-function to achieve higher power quality. On this basis, a dual-time scale energy management method is proposed to minimize the electricity purchasing cost. The reference power of each controllable unit is optimized in the long time scale, and the parameters of improved droop control are optimized in the short time scale. Finally, a case study is conducted on the ±10 kV three-terminal hybrid MMC-based ring MVDC-DS, and the results indicate that the proposed method can improve the economy and power quality of system, and help to realize the normal system operation under different conditions.

The dried plant of Tadehagi triquetrum is called Hulu Tea in traditional Chinese medicine (TCM). This study attempted to analyze the antioxidant products of the interaction with cellular reactive oxygen species. LAEH, a lyophilized aqueous extract of Hulu Tea, was prepared and analyzed using high-performance liquid chromatography. Eight phytophenols were found, namely, rutin, isoquercitrin, p-coumaric acid, p-hydroxybenzoic acid (pHBA), kaempferol, protocatechuic acid, afzelin, and daidzein. The antioxidant levels of the phytophenols were evaluated using the 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO˙) trapping, 1,1-diphenyl-2-picryl-hydrazl (DPPH˙) trapping, Fe3+-reducing, and Cu2+-reducing assays. The reaction products of DPPH˙ with phytophenols were further analyzed using ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC-ESI-Q-TOF-MS/MS). A series of molecular ion and fragment peaks were observed, which corresponded to seven phytophenol–DPPH adducts, four phytophenol–phytophenol homodimers, and one p-coumaric acid–pHBA heterodimer. Seven possible heterodimer linking sites were further calculated using computational chemistry based on density functional theory with the methanol solvation model at the B3LYP (or UB3LYP)-D3/6-311+G(d,p) level. However, the 2,2′-linking heterodimer possessed the lowest enthalpy change (ΔH) value of −69.54 kcal mol−1; the 2,2′-bond presented a Laplacian bond order value of 1.083 and a bond length of 148.9 pm. In conclusion, the eight antioxidant phytophenols can produce three types of antioxidant products, phytophenol–radical adduct, phytophenol–phytophenol homodimer, and phytophenol–phytophenol heterodimer. The phytophenol–phytophenol heterodimer refers to the p-coumaric acid–pHBA 2,2′-linking heterodimer rather than the 2-8′ benzofuran p-coumaric acid/pHBA heterodimer.

Erastin-treated bone marrow-derived mesenchymal stem cells (bmMSCs) were prepared and used to compare the ferroptosis inhibitory bioactivities of four monostilbenes, including rhapontigenin (1a), isorhapontigenin (1b), piceatannol-3′-O-glucoside (1c), and rhapontin (1d). Their relative levels were 1c ≈ 1b > 1a ≈ 1d in 4,4-difluoro-5-(4-phenyl-1,3-butadienyl)-4-bora-3a,4a-diaza-s-indacene-3-undecanoic acid (C11-BODIPY), 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), and flow cytometric assays. The comparison highlighted two 4′-OH-containing monostilbenes (1c and 1b) in ferroptosis inhibitory bioactivity. Similar structure–activity relationships were also observed in antioxidant assays, including 1,1-diphenyl-2-picryl-hydrazl radical (DPPH˙)-trapping, 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide radical (PTIO˙)-trapping, and Fe3+-reducing assays. UPLC-ESI-Q-TOF-MS analysis of the DPPH˙-trapping reaction of the monostilbenes revealed that they can inhibit ferroptosis in erastin-treated bmMSCs through a hydrogen donation-based antioxidant pathway. After hydrogen donation, these monostilbenes usually produce the corresponding stable dimers; additionally, the hydrogen donation potential was enhanced by the 4′-OH. The enhancement by 4′-OH can be attributed to the transannular resonance effect. This effect can be used to predict the inhibition potential of other π–π conjugative phenolics.

Abnormally low or high levels of trace elements in poultry diets may elicit health problems associated with deficiency and toxicity, and impact poultry growth. The optimal supplement pattern of trace mineral also impacts the digestion and absorption in the body. For ducks, the limited knowledge of trace element requirements puzzled duck production. Thus, the objective of this study was to investigate the influence of dietary inclusions of coated and uncoated trace minerals on duck growth performance, tissue mineral deposition, serum antioxidant status, and intestinal microbiota profile. A total of 1,080 14-day-old Cherry Valley male ducks were randomly divided into six dietary treatment groups in a 2 (uncoated or coated trace minerals) × 3 (300, 500, or 1,000 mg/kg supplementation levels) factorial design. Each treatment was replicated 12 times (15 birds per replicate). Coated trace minerals significantly improved average daily gain (p p Lactobacillus, Sphaerochatea, Butyricimonas, and Enterococcus were found in birds fed with coated trace minerals. In conclusion, diets supplemented with coated trace minerals could reduce the risk of environmental contamination from excreted minerals without affecting performance. Furthermore, coated trace minerals may improve the bioavailability of metal ions and the colonization of probiotic microbiota to protect microbial barriers and maintain gut health.

To clarify the role of the B-ring in antioxidant flavonols, we performed a comparative study between galangin with a null B-ring and 3,5,7-trihydroxychromone without a B-ring using five spectrophotometric assays, namely, •O2−-scavenging, 1,1-diphenyl-2-picrylhydrazyl radical (DPPH•)-scavenging, 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide radical-scavenging, 2,2′-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) radical-scavenging, and Fe3+-reducing activity. The DPPH•-scavenging reaction products of these assays were further analyzed by ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC-ESI-Q-TOF-MS/MS) technology. In the five spectrophotometric assays, galangin and 3,5,7-trihydroxychromone dose-dependently increased their radical-scavenging (or Fe3+-reducing) percentages. However, galangin always gave lower IC50 values than those of 3,5,7-trihydroxychromone. In the UPLC-ESI-Q-TOF-MS/MS analysis, galangin yielded galangin-DPPH adduct MS peaks (m/z 662, 434, 301, 227,196, and 151) and galangin-galangin dimer MS peaks (m/z 538, 385, 268, 239, 211, 195, and 151). 3,5,7-Trihydroxychromone, however, only generated m/z 3,5,7-trihydroxychromone-DPPH adduct MS peaks (m/z 586, 539, 227, 196, and 136). In conclusion, both galangin and 3,5,7-trihydroxychromone could similarly undergo multiple antioxidant pathways, including redox-dependent pathways (such as electron transfer (ET) and ET plus proton transfer (PT)) and a non-redox-dependent radical adduct formation (RAF) pathway; thus, the null B-ring could hardly change their antioxidant pathways. However, it did improve their antioxidant levels in these pathways. Such improvement of the B-ring toward an antioxidant flavonol is associated with its π-π conjugation, which can provide more resonance forms and bonding sites.

Flos Chrysanthemi Indici (FCI) is a Chinese herbal medicine used in China for over 2000 years. In this study, its ethanol extract (EFCL) was found to protect against hydroxyl radical ( OH) induced oxidative damages to mesenchymal stem cells (MSCs) and DNA. To explore the mechanism, EFCL was further determined by chemical and antioxidant assays. Folin–Ciocalteu colorimetric assay suggested that content of total phenolics was 93.85 ± 3.56 mg catechin/g and HPLC analysis indicated a content of 10.05 ± 1.44 mg/g as chlorogenic acid in EFCI. Antioxidant assays revealed that EFCI could also scavenge O 2 − radical (IC 50 58.74 ± 1.30 μg/mL), DPPH radical (IC 50 46.46 ± 1.35 μg/mL) and ABTS + radical (IC 50 20.59 ± 0.52 μg/mL), bind Fe 2+ (IC 50 364.27 ± 19.57 μg/mL) and Cu 2+ (IC 50 734.77 ± 34.69 μg/mL), reduce Fe 3+ (IC 50 147.11 ± 11.09 μg/mL) and Cu 2+ (IC 50 35.69 ± 3.14 μg/mL). On the basis of mechanistic analysis, we concluded that FCI can effectively protect against hydroxyl-induced damages to DNA and MSCs, therefore FCI shows promise as a possible therapeutic reagent for many diseases. The effect may be mainly attributed to phenolics especially chlorogenic acid, which exerts the antioxidant action possibly through metal-chelating, and radical-scavenging which is via hydrogen atom transfer (HAT) and/or sequential electron proton transfer (SEPT) mechanisms.

As a phenolic alkaloid occurring in Cruciferous plants, sinapine was observed to protect mesenchymal stem cells (MSCs) against ·OH-induced damage in this study. It was also found to prevent DNA from damage, to scavenge various free radicals (·OH, ·O2(-), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid diammonium salt) (ABTS)(+·), and 1,1-diphenyl-2-picrylhydrazyl radical (DPPH·)), and to reduce Cu(2+) to Cu(+). To further explore the mechanism, the end-product of sinapine reaction with DPPH· was determined using HPLC-electrospray ionization (ESI)-MS/MS and HPLC-diode array detector (DAD). Four molecular ion peaks (m/z 701, 702, 703, and 351) in HPLC-ESI-MS/MS analysis indicated a radical adduct formation (RAF) pathway; while a bathochromic shift (λ(max) 334→475 nm) in HPLC-DAD indicated the formation of quinone as the oxidized product of the phenolic -OH group. Based on these results, it may be concluded that, (i) sinapine can effectively protect against ·OH-induced damage to DNA and MSCs; such protective effect may provide evidence for a potential role for sinapine in MSC transplantation therapy, and be responsible for the beneficial effects of Cruciferous plants. (ii) The possible mechanism for sinapine to protect against ·OH-induced oxidative damage is radical-scavenging, which is thought to be via hydrogen atom (H·) transfer (HAT) (or sequential electron (e) proton transfer (SEPT))→RAF pathways.

In this article, we determine the pH effect and chemical mechanism of antioxidant higenamine by using four spectrophotometric assays: (1) 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide radical (PTIO&bull, )-scavenging assay (at pH 4.5, 6.0, and 7.4), (2) Fe3+-reducing power assay, (3) Cu2+-reducing power assay, and (4) 1,1-diphenyl-2-picryl-hydrazyl (DPPH&bull, )-scavenging assay. The DPPH&bull, scavenging reaction product is further analyzed by ultra-performance liquid chromatography, coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC-ESI-Q-TOF-MS/MS) technology. In the four spectrophotometric assays, higenamine showed good dose-response curves, however, its IC50 values were always lower than those of Trolox. In UPLC-ESI-Q-TOF-MS/MS analysis, the higenamine reaction product with DPPH&bull, displayed three chromatographic peaks (retention time = 0.969, 1.078, and 1.319 min). The first gave m/z 541.2324 and 542.2372 MS peaks, while the last two generated two similar MS peaks (m/z 663.1580 and 664.1885), and two MS/MS peaks (m/z 195.9997 and 225.9971). In the PTIO&bull, scavenging assays, higenamine greatly decreased its IC50 values with increasing pH. In conclusion, higenamine is a powerful antioxidant&mdash, it yields at least two types of final products (i.e., higenamine-radical adduct and higenamine-higenamine dimer). In aqueous media, higenamine may exert its antioxidant action via electron-transfer and proton-transfer pathways. However, its antioxidant action is markedly affected by pH. This is possibly because lower pH value weakens its proton-transfer pathway via ionization suppression by solution H+, and its electron-transfer pathway by withdrawing the inductive effect (-I) from protonated N-atom. These findings will aid the correct use of alkaloid antioxidants.

A new method about location for single-phase grounding fault is proposed in this paper which is based on wide-area synchronizing information. This method is based on the line model of distributed parameters in distribution network, and constructs a fault location function according to the relations between fault current and fault distance. The transverse fault current which is corresponding to the hypothetic fault distance can be obtained using the synchronized information of the currents and voltages from two ends of a line, and the maximum transverse fault current can be obtained also using the interactive search algorithm on the whole line, the distance which is corresponding to the maximum of the transverse fault current is the fault distance. Through a lot of computer simulations using the MATLAB and field experiments, the results show that the method is dependable and high precision. Furthermore, the new method can be generalized to the other fault types