The extraction and quantitative determination of phenolic compounds (including phenolic acids, flavones, flavanols, alkaloid, tannins, procyanidins, and naphthoquinone) from the walnut kernel and its ...pellicle were performed by ultra-high-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). Effective parameters on the tandem MS conditions, chromatographic conditions, and extraction solvents were evaluated and optimized. Under optimum condition, limits of detection and linearity were 0.000565–33.3 μg/g and 10–1000 ng/mL with
r
-values > 0.9952, respectively. The relative standard deviation from extraction recovery was from 74.27 ± 2.81% to 109.52 ± 4.33%, with precision values of < 15%. The proposed method was applied for simultaneous extraction and determination of phenolic compounds not only in the walnut kernel and its pellicle, but also in other tree nuts.
The high variability and unpredictability of the plasma concentration of voriconazole (VRC) pose a major challenge for clinical administration. The aim of this study was to develop a population ...pharmacokinetics (PPK) model of VRC and identify the factors influencing VRC PPK in patients with talaromycosis. Medical records and VRC medication history of patients with talaromycosis who were treated with VRC as initial therapy were collected. A total of 233 blood samples from 69 patients were included in the study. A PPK model was developed using the nonlinear mixed-effects models (NONMEM). Monte Carlo simulation was applied to optimize the initial dosage regimens with a therapeutic range of 1.0–5.5 mg/L as the target plasma trough concentration. A one-compartment model with first-order absorption and elimination adequately described the data. The typical voriconazole clearance was 4.34 L/h, the volume of distribution was 97.4 L, the absorption rate constant was set at 1.1 h
-1
, and the bioavailability was 95.1%. Clearance was found to be significantly associated with C-reactive protein (CRP). CYP2C19 polymorphisms had no effect on voriconazole pharmacokinetic parameters. Monte Carlo simulation based on CRP levels showed that a loading dose of 250 mg/12 h and a maintenance dose of 100 mg/12 h are recommended for patients with CRP ≤ 96 mg/L, whereas a loading dose of 200 mg/12 h and a maintenance dose of 75 mg/12 h are recommended for patients with CRP > 96 mg/L. The average probability of target attainment of the optimal dosage regimen in CRP ≤ 96 mg/L and CRP > 96 mg/L groups were 61.3% and 13.6% higher than with empirical medication, and the proportion of C
min
> 5.5 mg/L decreased by 28.9%. In conclusion, the VRC PPK model for talaromycosis patients shows good robustness and predictive performance, which can provide a reference for the clinical individualization of VRC. Adjusting initial dosage regimens based on CRP may promote the rational use of VRC.
•Notable correlations between pellicle colors and phenolics in kernel without pellicle.•Positive correlations between TPCs of three forms in pellicle and their colors.•Dark walnuts with high contents ...of flavanols, flavones and flavonols in free form.
Although walnut kernels are a rich source of phenolic compounds, little is known about the profiles of phenolic compound forms in various colored-pellicle walnuts, which may be important for product development and utilization. In this work, the free, esterified and bound forms of phenolic compounds in various colored-pellicle walnuts were identified using ultra-high-performance liquid chromatography coupled to tandem mass spectrometry ((UHPLC-MS/MS). The total phenolics (TPCs) in pellicle, kernel without pellicle and whole kernel (with pellicle) were presented in the free form (62.6%) and bound form (1.30 %–12.2 %). Positive correlations were found between the TPCs of three forms in pellicle and the pellicle color, with correlation coefficients of 0.920, 0.990 and 0.940. In addition, the phenolic compounds in free form in the whole kernel (with dark pellicle) demonstrated notable advantages in flavanols, flavones and flavonols contents, particularly (+)-catechin (C) (40.7 μg/g) and epicatechin (EC) (25.8g/g), which were 2–153 times higher than other phenolic compounds in free form. Furthermore, the dark group of esterified phenolic acids showed advantages, particularly ellagic acid (428 μg/g) and gallic acid (130 μg/g).
Rapid wear of ball-end cutters results in short service life when milling difficult-to-cut materials, such as titanium and Ni-based superalloys. In this study, an oscillating milling strategy was ...proposed which attempted to improve uniform wear degree of the cutting edge by making full use of the wear overlap regions, thus extending service life of the ball-end cutter. Firstly, the cutting edge was divided into several cutting units(CUs) and the equal linear speed was used as a criterion for establishing cutting parameters. Subsequently, the tool wear model was established to describe the wear resistance of CUs along the cutting edge. Based on it, an optimization model for the oscillating milling strategy based on uniform wear theory was developed. Cutting tasks for different CUs were assigned according to the optimization model and were executed sequentially by oscillating cutting. Cutting experiments were carried out on both planar and free-form surfaces of Ni-based superalloy GH4169/ Ni718. Results showed that the machining strategy significantly increased tool service life by increasing the uniform wear degree of the cutting edge, in addition to improving the surface consistency of the workpiece.
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•An oscillating milling strategy based on uniform wear theory is proposed to improve the service life of ball-end cutter.•A flank wear model of ball-end cutter considering tool wear overlap region is established.•An optimization model of cutting task allocation based on oscillating cutting strategy is established.•The proposed machining strategy improves both tool service life and workpiece surface quality.
Constructed wetlands (CW) are a promising treatment technology for decentralized rural sewage. However, the pollutant removal efficiency of CW is low due to the limitation of DO concentration. In ...this study, a falling water enhanced tidal flow constructed wetlands (F-TFCW) was constructed to solve the problems of insufficient oxygen supply and low pollutant removal efficiency in CW. In this regard, the effects of falling water reoxygenation, tidal operation, and flood rest ratio (F/R) on the pollutant removal performance of F-TFCW were examined. Also, the pollutant removal mechanism of F-TFCW was revealed through microbial analysis and biochar XPS characterization. The results showed that the COD, NH4+-N, and TP removal rates of F-TFCW were 99.50 ± 0.21%, 87.16 ± 1.76%, and 88.43 ± 1.35%, respectively, when the F/R was 3:1. The falling water inflow and tidal operation significantly improved the reaeration influence of the constructed wetland. The microbial community analysis represented that the dominant bacteria of the F-TFCW could degrade organic compounds or adapt to tidal flow operation. The tidal operation remarkably changed the core microorganisms of the artificial wetland. In the flood phase of F-TFCW, the COD removal relied mainly on aerobic degradation and the biochar adsorption process. In the experimental step, the microbes degraded the organic matter adsorbed by biochar, which enabled a certain degree of biochar regeneration. This paper provided a new idea to enhance the pollutant treatment efficiency for constructed wetlands.
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•The removal rates of COD, NH4+-N and TP of F-TFCW were 99.50 ± 0.21%, 87.16 ± 1.76% and 88.43 ± 1.35% respectively.•The fall water intake can effectively reoxygenate the constructed wetlands.•Tidal flows can significantly alter the core species of microbial communities.•RelYing on in-situ regeneration of biochar, F-TFCW can efficiently remove high concentrations of organic matter.
Abstract Silicon carbide fiber‐reinforced SiC ceramic matrix composites (SiC f /SiC CMCs) based on a domestic KD‐SA SiC fiber were exposed to a wet oxygen atmosphere for 135 h at 800, 1100, and ...1300°C. The evolution of the microstructure and mechanical properties of SiC f /SiC CMCs have been systematically investigated following oxidation. For weight change, CMC‐1300 showed the greatest gain (0.394%), followed by CMC‐1100 (0.356%) and CMC‐800 (0.149%). The volatilization of boron oxide (B 2 O 3 ) combined with the slight oxidation of the SiC matrix at 800°C caused crack deflection and fiber pull‐out. The complete dissipation of the interphase could be found when the oxidation temperature increases to 1100°C, generated a fracture surface with brittle fracture characteristics. At 1300°C, crystalline SiO 2 hindered oxygen diffusion, with evidence of fiber pull‐out. Based on thermodynamic calculations and microscopic observations, we propose a mechanism to explain the thermal degradation of SiC f /SiC CMCs. This work offers valuable guidance for the fabrication of SiC f /SiC CMCs that are suitable for high‐temperature applications.
Silicon carbide fiber‐reinforced SiC ceramic matrix composites (SiCf/SiC CMCs) based on a domestic KD‐SA SiC fiber were exposed to a wet oxygen atmosphere for 135 h at 800, 1100, and 1300°C. The ...evolution of the microstructure and mechanical properties of SiCf/SiC CMCs have been systematically investigated following oxidation. For weight change, CMC‐1300 showed the greatest gain (0.394%), followed by CMC‐1100 (0.356%) and CMC‐800 (0.149%). The volatilization of boron oxide (B2O3) combined with the slight oxidation of the SiC matrix at 800°C caused crack deflection and fiber pull‐out. The complete dissipation of the interphase could be found when the oxidation temperature increases to 1100°C, generated a fracture surface with brittle fracture characteristics. At 1300°C, crystalline SiO2 hindered oxygen diffusion, with evidence of fiber pull‐out. Based on thermodynamic calculations and microscopic observations, we propose a mechanism to explain the thermal degradation of SiCf/SiC CMCs. This work offers valuable guidance for the fabrication of SiCf/SiC CMCs that are suitable for high‐temperature applications.
To test superconductors with high performance such as Nb3Sn Cable-in-Conduit Conductor (CICC) and superconducting magnets from small scale to large scale, the background magnetic field with high ...homogeneity is necessary. As a major national science and technology infrastructure project in china, the peak magnetic field of the Research System of Superconducting Magnets (RSSMs) can be up to 15 T and the maximum change rate of magnetic field is 1.5 T/s. To supply electrical power for the RSSMs including the background field superconducting magnet and the tested objects in the meanwhile, a direct current (DC) high power supply rated at 360 MW was designed, the rated current, ripple current and rated voltage are 240 kA, 1 kA and 1.5 kV respectively. Additionally, the maximum output pulse current, the ramp up speed and the pulse width in pulse mode of the DC high power supply are 1000 kA, 5000 kA/s and 100 ms respectively. As a result, the alternating current (AC) power supply system was estimated from the view point of available power. To reduce the ripple of the DC high power supply, the topology of eight power blocks' parallel connection with the interleaved control method is put forward. The simulating results of circulating current and pulse operation indicate the design proposal is an alternative option.
Experiment Advanced Superconducting Tokamak (EAST) has a high stored energy superconducting toroidal field (TF) magnet system, so a quench protection is required to discharge the TF coils stored ...energy. This paper proposes a quench protection scheme of the EAST toroidal superconducting magnet through the forced commutation analysis of DC circuit breaker (DCCB) paralleling fuse, in the meantime, two pyrobreakers (PB) are used as a backup to enhance reliability. Based on the requirements of quench protection of EAST toroidal field magnet, the main parameters are selected. Experimental results demonstrate the validity of the proposed case.
The impact of triazophos, bensulfuron-methyl, chlobenthiazone on soil biochemical characteristics in a paddy soil under controlled moisture (flooded soil) and temperature (25 degrees C) condition was ...studied. The electron transport system (ETS)/dehydrogenase activity displayed a negative correlation with triazophos, bensulfuron-methyl, chlobenthiazone concentrations, and the activity decreased as the concentration of the pesticides increased. The higher doses, 5 and 10 field rates, of triazophos, bensulfuron-methyl, chlobenthiazone significantly inhibited ETS activity, while lower rates failed to produce any significant reducing effect against the control. The relative toxicity of triazophos, bensulfuron-methyl, chlobenthiazone in decreasing the ETS activity was in the order: triazophos > chlobenthiazone > bensulfuron-methyl, irrespective of the rates of application. Triazophos, bensulfuron-methyl, chlobenthiazone caused an improvement in the soil phenol content and it increased with increasing concentration of triazophos, bensulfuron-methyl, chlobenthiazone. Triazophos, bensulfuron-methyl, chlobenthiazone incorporation did not produce any significant change in soil protein content. The response of biomass phospholipid content was nearly similar to ETS activity. The phospholipid content was decreased with the addition of triazophos, bensulfuron-methyl, chlobenthiazone in the order of triazophos > chlobenthiazone > bensulfuron-methyl; and the toxicity of applied amount was in the order: 10 FR (field rate) > 5 FR > 1.0 FR > 0.5 FR > control.
