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Objective To investigate the causes and treatment of delayed corneal epithelial healing after trans-epithelial photorefractive keratectomy (TPRK). Methods A case of a young female with delayed corneal epithelial healing after TPRK for myopia was retrospectively analyzed. Results Delayed corneal healing is a rare complication in the early stage after TPRK. In this case, it caused symptoms such as pain, blurred vision, glare and tearing. Long-term wearing of contact lenses, meibomian gland dysfunction and postoperative use of drugs that inhibited epithelial growth were risk factors for this patient. After comprehensive treatment with bandage soft contact lenses, sodium hyaluronate, deproteinized calf blood extractive, glucocorticoids, ganciclovir ophthalmic gel and corneal epithelial debridement, corneal epithelium healed completely, but haze grade 1 was present in the delayed healing area on 22nd postoperative day. After follow-up treatment, haze disappeared and cornea returned transparent half a year later. Conclusions Patients with risk factors for delayed corneal epithelial healing after TPRK should undergo a comprehensive preoperative examination. Delayed corneal epithelial healing should be treated early and comprehensively, while alerting to haze and herpes simplex virus infection.

Water use efficiency (WUE) is a key indicator for predicting the impacts of climate change on ecosystem carbon and water cycles. Most studies have explored the changes in the response environment of WUE at a particular scale. Few studies have examined how WUE responds to environments at multiple scales, thus limiting our in-depth understanding of the cross-scale carbon and water cycles. In this study, we measured photosynthesis and transpiration in situ periodically and continuously from June to October 2022 in a community dominated by Artemisia ordosica in Mu Us Sandy Land, and analyzed the seasonal variations in WUE at leaf, canopy, and ecosystem scales. The results showed there were significant seasonal variations in leaf water use efficiency (WUEL), canopy water use efficiency (WUET), and ecosystem water use efficiency (WUEE). WUEL was large in June and small in both August and September, ranging from 0.73-2.98 µmol • mmol-1. Both WUET and WUEE were lowest in June and highest in July and August, ranging from 0.10-7.00 and 0.06-6.25 µmol • mmol-1. WUEL was significantly negatively correlated with stomatal conductance. WUET was significantly positively correlated with canopy conductance and soil water content, and negatively correlated with vapor pressure deficit (VPD). There was a significant positive correlation between WUEE and soil water content (SWC10) in 10 cm soil depth. The structural equation model showed that SWC10 and air temperature affected net photosynthetic rate and transpiration rate by modifying stomatal conductance, and thus affecting WUEL. VPD and SWC10 affected WUET by altering transpiration. SWC10, air temperature, and VPD affected WUEE by regulating ecosystem gross primary productivity. The modelling of carbon and water cycles should thoroughly consider the path and intensity of the effect of environmental factors on WUE at multiple scales. [ABSTRACT FROM AUTHOR]

Objective: To develop a method for determination of benzo[a]pyrene and to analysis of benzo[a]pyrene content in commercially available infant milk powder., Methods: Firstly, infant milk powder was extracted with ether-petroleum ether(1∶1, V/V) under alkaline conditions, then saponified with 1. 5 mol/L potassium hydroxide ethanol solution. After purification by solid phase extraction column, it was separated on DB-EUPAH chromatographic column(20 m×0. 18 mm×0. 14 μm) and detected by gas chromatography-mass spectrometry, and quantified using D_(12)-benzo[a]pyrene internal standard., Results: When the benzo[a]pyrene in infant formula was spiked 0. 3, 1. 0, 5. 0 μg/kg, the average recoveries were 116. 7%、86. 0% and 96. 4%, respectively, and the relative standard deviations were 10. 5%、4. 2% and 4. 4%, respectively(n= 6). The limit of quantification was 0. 3 μg/kg, and the detection limit was 0. 1 μg/kg. A total of 40 domestic and imported infant milk powders sold in Hangzhou supermarkets were analyzed. The range of benzo[a]pyrene was <0. 1-0. 25 μg/kg, and the detection rate was 32. 5%., Conclusion: The method has the advantages of rapid operation, good purifying effect, sensitiveness and accuracy, and meets the requirements for detection of benzo[a]pyrene in infant milk powder. The investigation reveals that the benzo[a]pyrene content in the currently marketed infant milk powder is at a low level.

Objective: A method for the determination of 5 kinds of phthalate monoesters in urine by solid-phase extraction and gas chromatography-mass spectrometry was developed., Methods: After urine enzymatic hydrolysis by β-glucuronidase, the sample was pretreated by SPE. Phthalate monoesters were eluted by boron trifluoridemethanol complex, and determined by gas chromatograph-mass spectrometer with DB-5 ms Phenomenex( 30 m × 0. 25 mm, 0. 25 μm)., Results: Within the concentration range of25. 0-1000 μg/L, the relationship between peak area and concentration of 5 kinds of phthalate monoesters presented linear relation. The correlation coefficient was 0. 9989-0. 9996, and the determination limit was 10. 0-15. 0 μg/L. The recoveries of phthalate monoesters were in the range of 80. 2%-97. 8% when set at 15. 0, 200 and 500 μg/L concentration levels, and the relative standard deviation was in the range of 4. 2%-10. 2%( n = 6). A total of 81 pregnant women were detected by this method and thedetection rate was 98. 7%., Conclusion: This method could be used in the simultaneous determination of 5 kinds of phthalate monoesters.

Objective: To establish a new qualitative and quantitative ultraperformance liquid chromatography-fluorescence detector / photodiode array detector with series double-detector method for the determination of eleven fluorescent whitening agents in paper food packaging materials., Methods: The sample was extracted with 40%acetonitrile water solution, separated by Waters ACQUITY UPLC BEH C_(18)column( 1. 7μm, 2. 1 mm × 100 mm) and eluted gradient. The excitation wavelength and emission wavelength of fluorescence detector( FLD) were 350 nm and 430 nm, and the wavelength of photodiode array detector( PDA) was 350 nm. The detectors were used in series to achieve qualitative and quantitative detection., Results: In the substrates of paper cups, paper bowls, paper trays and paper boxes, those eleven fluorescent whitening agents were separated properly. For both detectors, in the linear range of 25- 1000 ng / m L, the correlation coefficient was greater than 0. 99, and the recoveries of spiked recoveries were between 82. 2%- 104. 1% with the RSD less than 10%( n = 6). The detection limits ofthose eleven fluorescent whitening agents were 0. 20- 0. 28 mg / kg for FLD and 1. 4- 2. 5mg / kg for PDA., Conclusion: The eleven fluorescent whitening agents could be separated properly with complete separation, good shapes and high recovery rate. This method is easy to operate also. Thus it's an effective method to detect the fluorescent whitening agents in paper food packaging materials.