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Objective: To shorten the drying time of Lycium barbarum, increase its shelf life, improve the quality of dried L. barbarum products, and provide technical support for the development of wolfberry drying industry. Methods: Using L. barbarum as experiment material, after being permeated, ultrasonic treating, blanching, ultrasonic treating + permeation and ultrasonic treating + blanchting, far infrared drying test was carried out. The effects of different pretreatment methods on the far-infrared drying characteristics of L. barbarum were studied. Weibull distribution function was used to fit the drying process. The quality and microstructure of dried L. barbarum products were analyzed. Results: After being pretreated, the drying time of L. barbarum was significantly reduced, the drying rate was increased; Compared with L. barbarum without pretreatment before pre-dried, drying time after blanching pretreatment shortened 27.5%, the moisture ratio of the material decreased fastest, and drying rate was the highest. Weibull distribution function can simulate the far infrared drying process of L. barbarum under different pretreatment conditions. The range of r2 and χ2 was 0.991 73-0.999 15 and 8.13 41 × 10-5-8.846 79 × 10-4. The drying characteristics described by scale parameter (α) and shape parameter (β) were consistent with those in the drying characteristic curve. The dried product pretreated with ultrasound + permeation had the smallest color difference (6.756 4) compared with the fresh sample. The polysaccharide content inside the material (991.27 mg/g•DW) was the highest; The microstructure of the dry product obtained by the ultrasound + penetration group had the most voids, and the drying treatment had the least damage to its surface. Conclusion: Ultrasonic and osmotic pretreatment of L. barbarum before drying can not only shorten the drying time, but also improve the quality of its dried products.
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Currently, the main sample pretreatment methods for forensic toxic analysis are liquid-liquid extraction （LLE） and solid-phase extraction （SPE）. As a simple, convenient, and low-cost LLE method, dispersion liquid-liquid microextraction （DLLME） has high enrichment factor and good extraction efficiency, and therefore has attracted the attention of many researchers in the field of toxicology analysis in recent years. As a multi-functional microextraction method, DLLME has been widely used in the analysis of pesticides, sleeping sedatives, drugs and heavy metal poisons in forensic toxic analysis. Meanwhile, it can also be used in combination with such a variety of analytical instruments as gas chromatography-electron capture detectors （GC-ECD）, high performance liquid chromatography-diode array detectors （HPLC-DAD）. As a sample pretreatment method, DLLME has the advantages of simple operation, less use of organic solvent, reliable results and good reproducibility, thus can meet the requirements of modern court toxic analysis.
Asunto(s)
Toxicología Forense , Microextracción en Fase Líquida , Reproducibilidad de los Resultados , Extracción en Fase Sólida , SolventesRESUMEN
A method for determination of PCDD/Fs, PCBs and PCNs in soil sample was developed by using accelerated solvent extraction (ASE)-silica gel column cleanup-basic alumina column separation coupled with GC-MS/MS.The sample was extracted by ASE with Hexane-methylene chloride (Hex-DCM, 50∶50, V/V) at 120℃.The basic alumina column was used to separate PCDD/Fs, PCBs and PCNs.The extracts were eluted with Hex-DCM (95∶5, V/V) to obtain PCBs and PCNs, followed by Hex-DCM (50∶50, V/V) to obtain PCDD/Fs.The limits of detection (LOD) were in the range of 0.04-0.25 μg/L, 0.10-0.20 μg/L and 0.01-0.05 μg/L for PCDD/Fs, PCBs, PCNs, respectively.The relative standard deviations (RSDs) of average relative response factors (RRF) were below 13%.The recoveries of 13C-labeled internal standards of the three classes of analytes were 50%-95%, 51%-103% and 49%-74%, respectively.Concentrations of ∑PCDD/Fs, ∑PCBs and ∑PCNs in soil samples were 16.1-1148 pg/g, 6.6-152.6 pg/g and 10.9-99.5 pg/g, respectively.The results were consistent with that of high resolution mass spectrometer.
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Objective The aim of this study was to evaluate the commercial SepsityperTM kit and serum separator tube coupled with matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry for direct identification of microorganisms in a blood culture system.Methods A total of 138 clinical blood samples from clinical laboratory in Renji hospital were tested with two methods respectively from April to June of 2016.Performance of the assays were compared against that of conventional bacterial culture as a reference.Results A total of 138 nonduplicate positive blood culture samples were collected,including 70 (53.03％) gram negative samples,57 (43.18％) gram positive samples,3 fungus samples,2 mixed samples,and 6 false positive samples which were excluded from further analysis.The accuracy rate of SepsityperTM kit and serum separator tube was 91.67％ and 84.09％ in rapid identification of pathogen from blood samples,83.33％ and 61.36％ in correct identification to species level.The accuracy rate of SepsityperTM kit and serum separator tube was 98.57％ and 95.71％ in identifying gram-negative bacteria,87.72％ and 78.59％ in identifying gram-positive bacteria,respectively.The turnaround time for identification of each sample was 40 min by the commercial SepsityperTM kit and 25 min by serum separator tube.Conclusions MALDI SepsityperTM kit has shown slightly higher accuracy rate in identification of pathogen from blood sample than serum separator tube,but the difference is not significant (91.67％ vs.84.09％,P＞0.05).Compared with MALDI SepsityperTM kit,serum separator tube is a rapid,easy,and cost-effective pretreatment method for direct identification of microorganisms from blood cultures using MALDI-TOF mass spectrometry.
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Hepatic ischemia reperfusion injury (IRI) is a continuous process of damage of liver cells,which could cause a series of clinic reactions.Early owing to IRI,organ failure reaches 10％,and easily leads to acute and chronic liver transplantation rejection.Therefore,study on the treatment method of IRI is very important.Decreasing the adverse effect of IRI could significantly increase the amount of successful liver transplantation.This paper will explore mainly on the pretreatment methods of IRI.