A red fluorescence probe for reversible detection of HSO3-/H2O2 and its application in food samples and bioimaging.

Reducing agent SO2 and oxidant H2O2 are two essential substances in cells, and the balance between them is closely related to the survival of cells. SO2 derivative HSO3- is often used as food additive. Therefore, simultaneous detection of SO2 and H2O2 is of great significance in biology and food safety. In this work, we successfully developed a mitochondria-targeted red fluorescent probe (HBTI), which has excellent selectivity, high sensitivity and large Stokes shift (202 nm). HBTI and HSO3-/SO32- undergo Michael addition on the unsaturated C=C bond, and the addition product (HBTI-HSO3-) can react with H2O2 to restore the conjugated structure. Fluorescence changes from red to non-emissive and then restores to red, and can be detected quickly and visually. In addition, HBTI has been successfully targeted mitochondria, and achieved dynamic reversible response to SO2/H2O2 in living cells, and has been successfully applied to detect SO2 in food samples.

Tracking approach of double pendulum cranes with variable rope lengths using sliding mode technique.

Cranes are widely employed for transportation in many industrial fields. However, strong couplings and high nonlinearities increase difficulty of designing effective control methods for crane systems. Additionally, complex environments may bring uncertainties and unfavorable factors for the control problem. In this paper, we design an effective tracking approach for double pendulum cranes considering variable rope lengths problem by using sliding mode technique, to further improve the robustness and achieve the control objectives of accurate tracking, while effective suppression for double pendulum swing is also ensured. We design a proper sliding mode surface containing all state variables, which effectively suppresses swing angles of the payload and the hook. Then, the time delay estimator technique is used to estimate parameter uncertainty-related terms and the estimation errors are effectively tackled by using sliding mode technique. The effectiveness is rigorously proved by Lyapunov stability theory. At last, comprehensive simulations are implemented to show the proper performance.

[Acute risk assessment of cumulative dietary exposure to organophosphorus pesticide among people in Jiangsu province].

OBJECTIVE: To understand the cumulative dietary exposure of Jiangsu residents to organophosphorus (OPs) pesticide and make acute risk assessment. METHODS: Integrated the data of the nutrition and health status of residents in Jiangsu and the data of monitoring of OPs pesticide in agricultural products. Chlorpyrifos was selected as index compound (index chemical, IC), then use relative potency factor (RPF) approach which commended by EPA and simple distribution evaluation. Caloulated the dietary cumulative exposure of OPs pesticide among Jiangsu residents and compared with acute reference dose (ARfD), then made risk assessment. RESULTS: The exposure of rural group of age 3-6 and 7-11 were 133.84 microg/kg BW and 154.32 microg/kg BW, exceeded ARfD. The exposure level of kids and elder was higher than adults. The exposure level of rural residents were higher than urban residents. The highest contribution to the food of each age group was greengrocery and leek. CONCLUSION: The average level of exposure was safety in Jiangsu, high exposure children were at acute poisoning risk. High contribution food such as greengrocery and leek should be strengthen monitoring.

[Impacts that dimethoate inhibited the benchmark dose of acetylcholinesterase based on experimental designs].

OBJECTIVE: To obtain the impacts of experimental design on benchmark dose (BMD), and the result was applied to test the computer simulation by software Slob (optimal method to calculate the BMD: for a certain sample capacity, to add the experimental groups by reducing the amount of animals in each group) , consequently, this method can be widely used in the future. METHODS: Eighty adult female SD rats were ig given dimethoate 0.5, 1, 2, 4, 8, 16 and 32 mg/kg for 21 d, respectively. Rats were sacrificed, and acetylcholinesterase (AChE) activity in the hippocampus, cerebral cortex and serum of rats was determined after dimethoate was ig given to rats for 21 d. And then, the software package PROAST28.1 was applied to calculate the BMD. The four does groups of 10 animals (4 x 10 design) and 8 x 5 design were selected from 8 x 10 design to study the impacts of experimental design on BMD. RESULTS: Comparing with the normal control, the significant decline of AChE in hippocampus was observed in 2, 4, 8, 16 and 32 mg/kg groups (P < 0.05), whereas the significant decrease was obtained in 0.5, 1, 2, 4, 8, 16 and 32 mg/kg groups (P < 0.05). Taking the 8 x 10 design as the standard, the confidence interval of BMD calculated by both of 4 x 10 design and 8 x 5 design covered the BMD by 8 x 10 design. And also, confidence interval of BMD, calculated by design scheme 1, 2, 3, 4 and 6 of 4 x 10 design, wider than that of 8 x 5 design, but its scheme 5 narrower than 8 x 5 design. CONCLUSION: To add experimental groups in a certain sample capacity was the optimal method to calculate BMD, but was not the common toxicity experimental design (e. g. set four groups including control, low-dose, moderate-dose, high-dose group).