Microwave Assisted Synthesis of N-Doped Carbon Dots: an Easy, Fast and Cheap Sensor for Determination of Aspartic Acid in Sport Supplements.

In this work, determination of aspartic acid by N-doped carbon dots (N-CDs) was studied at optimum condition. Characterization and morphology of surface of N-CDs were carried out by FT-IR and HRTEM. N-doped carbon dots size was 10 nm. Quenching was very fast after addition of aspartic acid that is an important property of this sensor. Optimum conditions for pH and excitation wavelength were 8 and 360 nm, respectively. Linear dynamic range and limit of detection for aspartic acid were 0.5-50 µM and 90 nM, respectively. This method was used for aspartic acid determination in human serum and sport supplement powder as real samples. Performance of this sensor was also compared with other fluorescent sensors.

Performance of real-time strain elastography, transient elastography, and aspartate-to-platelet ratio index in the assessment of fibrosis in chronic hepatitis C.

OBJECTIVE: The purpose of this article is to evaluate the diagnostic performance of transient elastography, real-time strain elastography, and aspartate-to-platelet ratio index in assessing fibrosis in patients with chronic hepatitis C by using histologic Metavir scores as reference standard. SUBJECTS AND METHODS: Consecutive patients with chronic hepatitis C scheduled for liver biopsy were enrolled. Liver biopsy was performed on the same day as transient elastography and real-time strain elastography. Transient elastography and real-time strain elastography were performed in the same patient encounter by a single investigator using a medical device based on elastometry and an ultrasound machine, respectively. Diagnostic performance was assessed by using receiver operating characteristic curves and area under the receiver operating characteristic curve (AUC) analysis. RESULTS: One hundred thirty patients (91 men and 39 women) were analyzed. The cutoff values for transient elastography, real-time strain elastography, and aspartate-to-platelet ratio index were 6.9 kPa, 1.82, and 0.37, respectively, for fibrosis score of 2 or higher; 7.3 kPa, 1.86, and 0.70, respectively, for fibrosis score of 3 or higher; and 9.3 kPa, 2.33, and 0.70, respectively, for fibrosis score of 4. AUC values of transient elastography, real-time strain elastography, aspartate-to-platelet ratio index were 0.88, 0.74, and 0.86, respectively, for fibrosis score of 2 or higher; 0.95, 0.80, and 0.89, respectively, for fibrosis score of 3 or higher; and 0.97, 0.80, and 0.84, respectively, for fibrosis score of 4. A combination of the three methods, when two of three were in agreement, showed AUC curves of 0.93, 0.95, and 0.95 for fibrosis scores of 2 or higher, 3 or higher, and 4, respectively. CONCLUSION: Transient elastography, real-time strain elastography, and aspartate-to-platelet ratio index values were correlated with histologic stages of fibrosis. Transient elastography offered excellent diagnostic performance in assessing severe fibrosis and cirrhosis. Real-time elastography does not yet have the potential to substitute for transient elastography in the assessment of liver fibrosis.