A LIBS technique coupled with random forest based on variable importance (VIRF) was presented for the classification analysis of slag samples (open-hearth furnace slag, converter slag and high titanium slag).
Abstract The chemiluminescence (CL) behavior of five major flavonoid types in cerium (IV)‐rhodamine B system was investigated by flow‐injection. Strong CL was observed when cerium (IV) reacted with rhodamine B in sulfuric acid medium in the presence of flavonoids. This reaction system has been established as a simple, rapid, and highly sensitive flow injection CL analysis for quercetin and kaempferol, and their detection limit (3σ) was 2.7 and 0.22 nmol/L, respectively. The relative standard deviation (n=8) was 1.2% for 1.0 µmol/L quercetin and 1.9% for 0.5 µmol/L kaempferol. This method was successfully applied to the determination of quercetin in the hydrolysate of rutin and compared well with the high performance liquid chromatography (HPLC) method. From a comparison of several related flavonoids, it was concluded that only flavonoids that contain a free 3‐hydroxyl and 2, 3‐double bond in conjugation with 4‐oxo function could produce a relatively strong CL emission.
In this study, we developed a method for determining cotinine and 3-hydroxycotinine in human serum and established a methodology for an in-depth study of tobacco exposure and health. After the proteins in the human serum samples were precipitated with acetonitrile, they were separated on a ZORBAX SB-Phenyl column with a mobile phase of methanol encompassing 0.3% formic acid-water encompassing 0.15% formic acid. The measurement was performed on an API5500 triple quadrupole mass spectrometer in the multiple reaction monitoring mode. Cotinine, 3-hydroxycotinine, and cotinine-d3 isotope internal standards were held for 2.56 minutes, 1.58 minutes, and 2.56 minutes, respectively. In serum, the linear range was 0.05 to 500 ng·mL-1 for cotinine and 0.50 to 1250 ng·mL-1 for 3-hydroxycotinine. The lower limit of quantification (LLOQ) was 0.05 ng·mL-1 and 0.5 ng·mL-1 for cotinine and 3-hydroxycotinine, respectively. The intra-day and inter-day relative standard deviations were <11%, and the relative errors were within ± 7%. Moreover, the mean extraction recoveries of cotinine and 3-hydroxycotinine were 98.54% and 100.24%, respectively. This method is suitable for the rapid determination of cotinine and 3-hydroxycotinine in human serum because of its rapidity, sensitivity, strong specificity, and high reproducibility. The detection of cotinine levels in human serum allows for the identification of the cutoff value, providing a basis for differentiation between smoking and nonsmoking populations.
Abstract A new fluorogenic probe for sodium new houttuyfonate (SNH) was proposed. 4‐Methylumbelliferyl‐2,4‐dinitrobenzenesulfonate (4‐MUDNBS) was a nonfluorescent compound and was synthesized via the one‐step reaction of 4‐methylumbelliferone (4‐MU) with 2,4‐dinitrobenzenesulfonyl chloride. In basic media, SNH was decomposed to produce sodium sulfite, which then reacted with 4‐MUDNBS to yield highly fluorescent 4‐MU, hence leading to the fluorescence increase of the reaction solution. A linear correlation existed between the emission intensity and the concentration of SNH within the range from 0.5 to 15 μg·mL −1 with a detection limit of 0.15 μg· mL −1 (3 δ ). The effect of substituents on the benzenesulfonyl moiety of the probe is discussed, and the presence of electronegative groups is favorable for the proposed cleavage reaction.
Abstract Background Our study aims to evaluate the umbilical vein (UV) hemodynamic change in the prenatal cohort of pregnancies diagnosed with abnormal placental cord insertion (aPCI). Methods From January 2022 to December 2022, the fetal umbilical cord insertion site was sonographically examined in singleton fetuses, and umbilical cord blood flow was calculated. The umbilical artery and UV Doppler flow indexes were assessed in cases of normal and abnormal cord insertion. Results Among 570 singleton fetuses between 18 + 0 and 40 + 6 weeks of gestation in the final study, the umbilical vein blood flow (UVBF) in the 3 groups of normal umbilical cord insertions, marginal umbilical cord insertions, and velamentous umbilical cord insertions was 145.39 ml/min, 146.18 ml/min, and 93.96 ml/min, respectively. UVBF was significantly lower in the velamentous cord insertion (VCI) group than in the other groups (P < 0.05). Compared with the normal cord insertions group, lower birth weight (2820 ± 527 g vs. 3144 ± 577 g, P < 0.05), delivery at an earlier gestational age (38.0 ± 1.55 weeks vs. 38.8 ± 2.34 weeks, P < 0.05), higher bicarbonate (25.08 ± 1.72 mmol/L vs. 22.66 ± 4.05 mmol/L, P < 0.05), and higher standard base excess (−1.14 ± 1.50 mmol/L vs. −3.30 ± 3.22 mmol/L, P < 0.05) were found in the VCI group. Conclusions We observed lower UVBF volume with aPCI. Hence, we propose UVBF analysis to evaluate fetal aPCI according to UV hemodynamics as an advisory in prenatal care. This would be useful and improve obstetricians’ clinical explanation about the potential prenatal consequences so that parents can opt for future prenatal care during pregnancy.
A new rhodol dye 3 with an ESIPT unit has been successfully developed, which can serve as a convenient and universal platform for developing ratiometric sensing systems based on the unique spirocyclic ring-opening process. As a model platform, rhodol 3 hydrazide (4) was prepared and it showed ratiometric response toward Cu2+.
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