Insights into the loss of glucoraphanin in post-harvested broccoli--Possible involvement of the declined supply capacity of sulfur donor.

The loss of characteristic nutrient glucoraphanin during the shelf life seriously affects the nutritional quality of broccoli. Here, we monitored the changes in the levels of sulfur donors (cysteine and glutathione) required for glucoraphanin biosynthesis. Similar to glucoraphanin, cysteine content decreased sharply. Continuous down-regulation of BoCysK1 and BoCysK2 genes encoding cysteine synthase might account for cysteine loss. Contrarily, glutathione content accumulated steadily, which might owe to the up-regulation of biosynthetic gene (BoEC1). Additionally, the change of malondialdehyde content was positively correlated with glutathione, implying that oxidative stress might stimulate glutathione accumulation. Nevertheless, the expression of BoGSTF11 gene encoding glutathione S-transferases was down-regulated, which blocked the supply of glutathione. The increase in the content of raphanusamic acid (degradation product) indicated that insufficient supply of sulfur donors not only could constrain the biosynthesis of glucoraphanin but also triggered its degradation.

Exogenous Melatonin Alleviated Leaf Yellowing via Inhibiting Respiration and Ethylene Biosynthesis during Shelf Life in Pakchoi.

Postharvest yellowing of leafy plant is a manifestation of senescence, and melatonin (MT) is known to delay leaf senescence in some higher plants. Herein, we investigated the effect of exogenous MT treatment on postharvest pakchoi by monitoring the ethylene biosynthesis and respiratory metabolism. Results showed that exogenous MT effectively extended the shelf life, delayed leaf yellowing, minimized the alteration in Fv/Fm ratio and maintained higher integrity of chloroplast in pakchoi. There was a significant correlation between yellowing index, respiration rate and ethylene production. MT treatments greatly delayed the yellowing process of pakchoi that was associated with the reduced activity of glycolysis pathway and tricarboxylic acid cycle (TCA), increased proportion of pentose phosphate pathway (PPP) in respiratory metabolism, as manifested by the lower activity of phosphohexose isomerase (PHI), succinate dehydrogenase (SDH) and cytochrome C oxidase (COX), downregulated the expression of their corresponding genes, but enhanced the activity and expression level of 6 phosphogluconate dehydrogenase (6PGDH). MT also markedly maintain chlorophyll content by inhibiting ethylene production and action during shelf life, likely a consequence of reduced activities of 1-aminocyclopropane-1-carboxylate (ACC) synthase (ACS) and ACC oxidase (ACO), as well as the expression levels of their related genes. These results collectively indicate that melatonin alleviated leaf yellowing of postharvest pakchoi might be attributed to the suppression of the ethylene biosynthesis and respiratory metabolism, and our findings contribute to provide a good candidate measure for extending shelf life and reducing postharvest loss of pakchoi.

Synchronization in Finite-Time of Delayed Fractional-Order Fully Complex-Valued Dynamical Networks via Non-Separation Method.

The finite-time synchronization (FNTS) problem for a class of delayed fractional-order fully complex-valued dynamic networks (FFCDNs) with internal delay and non-delayed and delayed couplings is studied by directly constructing Lyapunov functions instead of decomposing the original complex-valued networks into two real-valued networks. Firstly, a mixed delay fractional-order mathematical model is established for the first time as fully complex-valued, where the outer coupling matrices of the model are not restricted to be identical, symmetric, or irreducible. Secondly, to overcome the limitation of the use range of a single controller, two delay-dependent controllers are designed based on the complex-valued quadratic norm and the norm composed of its real and imaginary parts' absolute values, respectively, to improve the synchronization control efficiency. Besides, the relationships between the fractional order of the system, the fractional-order power law, and the settling time (ST) are analyzed. Finally, the feasibility and effectiveness of the control method designed in this paper are verified by numerical simulation.

The Dissipation of Cyazofamid and Its Main Metabolite CCIM During Wine-Making Process.

Few studies have focused on the residues of cyazofamid and its main metabolite CCIM (4-chloro-5-p-tolylimidazole-2-carbonitrile) in the wine making process, which is crucial to evaluate the potential food risk of cyazofamid and CCIM. In this work, detailed study has been conducted on the evaluation of the fate of cyazofamid and its main metabolite CCIM during the wine-making process. The targeted compounds cyazofamid and CCIM were separated and determined by high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) and processing procedure including washing, peeling, fermentation, and clarification. Results showed that residues of cyazofamid and CCIM decreased significantly in wine processing. The dissipation of cyazofamid in the fermentation process followed the first-order of kinetics, and the half-life of cyazofamid was 46.2-63.0 h, whereas, the residues of CCIM, in the three treatments, decreased with time elapse. The processing factors (PFs) were all less than one in different processing processes, and the PFs ranges of cyazofamid and CCIM were 0.003-0.025 and 0.039-0.067 in three treatments in the overall process. The outcome indicated that the whole process could significantly reduce the residues of cyazofamid and CCIM in red and white wines. The results might provide more precise risk assessments of cyazofamid in the wine-making process.

All solid-state electromagnetic pulse simulator based on the 4H-SiC photoconductive semiconductor switch.

To study the damage and protection mechanism of an electromagnetic pulse to an electronic system, an all solid-state high-voltage pulse power with photoconductive semiconductor switch is developed, which is a component of the bounded wave electromagnetic pulse simulator. The output peak voltage of the prepared all solid-state pulsed power source was 74.5 kV, the risetime was 2.05 ns, and the pulse width was 22 ns. In addition, the peak voltage of the output pulse of the all solid-state pulsed power source could be regulated. The all solid-state electromagnetic pulse simulator developed in this work can generate an electromagnetic environment with a risetime of 2.2 ns and a pulse width of 23.5 ns.

The dissipation of cyazofamid and its main metabolite CCIM during tomato growth and tomato paste making process.

In several studies focused on the residues of cyazofamid and its main metabolite 4-chloro-5-p-tolylimidazole-2-carbonitrile (CCIM) on tomato where it is widely used, CCIM has been shown to have higher acute toxicity than cyazofamid, and this is crucial to evaluate the potential food risk of cyazofamid and CCIM. In this study, the dissipation of cyazofamid and CCIM during tomato growth and tomato paste making process were assessed. The targeted compounds cyazofamid and CCIM were determined by LC-MS/MS. The results indicated that the half-life of cyazofamid was 4.6 days after applying in the field, and the maximum value of CCIM was 0.08 mg/kg at 3 days after the last application of cyazofamid, then gradually decreased. In addition, the concentrations of cyazofamid and CCIM were affected by different processing steps including washing, peeling, homogenisation, simmering, and sterilisation. Results showed that the mean losses of cyazofamid and CCIM were 92.3% and 75.2% after washing and peeling. The Processing Factor (PF) values were all less than 1. Especially for peeling, the PFs of cyazofamid and CCIM were 0.12 and 0.04, respectively.

The dissipation of thiamethoxam and its main metabolite clothianidin during strawberry growth and jam-making process.

Few studies focused on the residue of thiamethoxam and its metabolite clothianidin on strawberry where it is widely used, despite this is essential to assess the potential food risk of thiamethoxam and its main metabolite clothianidin. In this study, the dissipation of thiamethoxam and its metabolite clothianidin during strawberry growth and jam-making process were assessed. The strawberry was sprayed with thiamethoxam based on the field application to investigate the dissipation of thiamethoxam as well as clothianidin formation. The half-life of thiamethoxam in strawberry was 9.0 days and the concentration of clothianidin in strawberry gradually increased from 0.55 to 11 µg/kg within 30 days. In addition, the amount of thiamethoxam decreased by 51.7% and clothianidin decreased by 40.2% during the homogenization process. The processing factor values of whole processing all less than 1 except simmering. This results from this study will not only help to understand the dissipation kinetics of thiamethoxam and clothianidin in the strawberry, but also facilitate to make more accurate risk assessments of them during strawberry jam making process.

Protective effect of hydrogen-rich water on liver function of colorectal cancer patients treated with mFOLFOX6 chemotherapy.

The present study was conducted to investigate the protective effect of hydrogen-rich water on the liver function of colorectal cancer (CRC) patients treated with mFOLFOX6 chemotherapy. A controlled, randomized, single-blind clinical trial was designed. A total of 152 patients with CRC were recruited by the Department of Oncology of Taishan Hospital (Taian, China) between June 2010 and February 2016, among whom 146 met the inclusion criteria. Subsequently, 144 patients were randomized into the treatment (n=80) and placebo (n=64) groups. At the end of the study, 76 patients in the hydrogen treatment group and 60 patients in the placebo group were included in the final analysis. The changes in liver function after the chemotherapy, such as altered levels of alanine aminotransferase (ALT), aspartate transaminase (AST), alkaline phosphatase, indirect bilirubin (IBIL) and direct bilirubin, were observed. The damaging effects of the mFOLFOX6 chemotherapy on liver function were mainly represented by increased ALT, AST and IBIL levels. The hydrogen-rich water group exhibited no significant differences in liver function before and after treatment, whereas the placebo group exhibited significantly elevated levels of ALT, AST and IBIL. Thus, hydrogen-rich water appeared to alleviate the mFOLFOX6-related liver injury.