Detection of nitroaromatics based on aggregation induced emission of barbituric acid derivatives.

Barbituric acid derivatives with typical aggregation induced emission (AIE) are reported. Their emission wavelengths varied with water fraction of their solution. UV-visible absorption spectroscopy and theoretical calculations revealed the intramolecular charge transfer (ICT) possibility from donor to acceptor and the mechanism was confirmed as a restriction of intramolecular motion (RIM). The AIE properties were affected by the different substituents on barbituric acid. When the molecular volume increased, the AIE effect decreased. Fluorescent quenching mechanism was applied to detect nitroaromatic explosives. For 2,4,6-trinitrophenol (PA), one of the derivatives 5-(4-diphenylamino styrene)-1,3-diphenyl-barbituric acid in THF/H2O mixture (1:9, v/v), showed amplified fluorescence quenching with a maximum Stern-Volmer quenching constant of 4.1 × 104 M-1. The solid phase paper test based on 5-(4-diphenylamino styrene)-1,3-diphenyl-barbituric acid also showed a superior sensitivity toward PA both in vapor and solution.

[Measurement of retinal nerve fiber layer thickness in Leber hereditary optic neuropathy by optical coherence tomography].

OBJECTIVE: To evaluate retinal nerve fiber layer (RNFL) thickness in patients and unaffected carriers of Leber hereditary optic neuropathy (LHON) by optical coherence tomography (OCT). METHODS: This case-control study enrolled 42 LHON maternal family members with mitochondrial DNA G11778A mutation and 100 normal volunteers. RNFL thickness was measured by Stratus OCT in each participant. Mean RNFL thickness of each quadrant, as well as 360° average were calculated and compared in normal controls, LHON carries and LHON patients. RESULTS: Among LHON maternal family members, 15 cases were unaffected carriers who were subgrouped as normal-fundus-appearing carriers (10 cases) and preclinical carriers (5 cases). Twenty seven LHON patients included 9, 5, and 13 cases in the early, advancing and advanced stages, respectively. Normal fundus-appearing carriers showed normal RNFL thickness of each quadrant and 360° average. Preclinical carriers and early-staged patients showed no significant difference in RNFL thickness of each quadrant and 360° average (P = 0.138 to 0.645), yet both showed thicker RNFL in temporal, superior and inferior quadrant, as well as 360° average, if compared with normal controls (P = 0.000 to 0.018). Compared with normal controls, preclinical carriers and early-staged patients, advancing LHON patients showed thinner RNFL in temporal and inferior quadrant, as well as 360° average (P = 0.000 to 0.005). Advanced LHON patients showed thinner RNFL in each quadrant and 360° average, compared with normal controls, LHON carriers, and advancing cases (P = 0.000 to 0.037). CONCLUSIONS: RNFL thickness in LHON patients and unaffected carriers was characterized by OCT in this study, which would improve the understanding of the natural course of LHON.

[Quantitative determination of the (E) - and (Z) -diastereomers of resveratrol and resveratrol glucoside in the roots of Polygonum cuspidatum by HPLC and elementary study on their fluorescence].

AIM: To establish an optimal HPLC method for the determination of the (E)- and (Z)-diastereomers of resveratrol and resveratrol glucoside from the roots of Polygonum cuspidatum. METHODS: The determination was conducted by using reversed-phase high liquid chromatography. Nucleodur 100-5 C18 column (250 mm x 4.6 mm ID, 5 microm), and a mobile phase program of gradient elution with isopropyl alcohol and water at a flow rate of 0.6 mL x min(-1) was employed. The fluorescence detection wavelengths were: lambda(ex) 334 nm, lambda(em) 404 nm. RESULTS: A good linear relationship was obtained under the optimum condition. The average recoveries were 96.7%, 99.1% for the (E)-diastereomers of resveratrol and resveratrol glucoside, 91.1%, 93.7% for the (Z)-diastereomers of resveratrol and resveratrol glucoside, respectively. The RSD of E-resveratrol and its glucoside were 1.34% and 0.72%, respectively. The RSD of Z-resveratrol and its glucoside were 1.27% and 2.08%, respectively. CONCLUSION: This method is accurate and reliable for the quantity analysis of the (E)- and (Z)-diastereomers of resveratrol and resveratrol glucoside in the roots of Polygonum cuspidatum.