A novel reversed phase high performance liquid chromatography method to accurately determine low concentrations of curcumin in rat plasma

Due to its lipophilic nature, curcumin levels in plasma are very low after oral administration, and therefore hard to detect. A number of chromatographic methods, including LC/MS have been developed. Although the LC/MS method is sensitive, the matrix effect can be difficult to handle. Furthermore, LC/MS equipment is relatively expensive compared to the conventional RP-HPLC. Therefore, the aim of this study was to develop a sensitive and reliable method for the determination of curcumin concentration in plasma using an RP-HPLC. Curcuma longa extract was used which contains three curcuminoids. The method started by selection of mobile phase to optimally separate the curcuminoids. The best mobile phase composition was used to analyze the plasma samples. Rat plasma was spiked with curcumin and processed for protein precipitation followed by liquid-liquid extraction of curcuminoids and an internal standard, emodin. Chromatogaphic separation of curcuminoids and emodin was achieved using a Knauer C-18 column (250 x 4.6 mm; particle size: 5µm) and a gradient program of mobile phase of three solvents, methanol -acetonitrile-1% acetic acid. A gradient elution was applied with increasing the ratio of the volume percentages of acetonitrile to acetic acid from 50/45 to 53/42 during 5 minute and thereafter elution was isocratic for 15 minute. The methanol concentration was kept constant at 5 vol-% during the whole run. The method was validated according to the FDA guidelines.The method was selective, with an excellent resolution (Rs value > 2.5). The peak shape of both curcumin and emodin were symmetric with a tailing factor of 0.9-1.1. The method linearity (correlation coefficient of 0.999) was demonstrated at 6 to 200 ng/mL. The intra and inter-day precision was 5.90-8.50% and 5.37-11.26%, respectively; the intra- and inter-day accuracy was 92.47-103.61% and 96.17-105.70%, respectively. In conclusion, the RP-HPLC method meets the validation requirements as described in the FDA guidelines and is applicable to accurately quantify curcumin concentrations as low as 6 ng/mL in rat plasma samples

A novel reversed phase high performance liquid chromatography method to accurately determine low concentrations of curcumin in rat plasma

Due to its lipophilic nature, curcumin levels in plasma are very low after oral administration, and therefore hard to detect. A number of chromatographic methods, including LC/MS have been developed. Although the LC/MS method is sensitive, the matrix effect can be difficult to handle. Furthermore, LC/MS equipment is relatively expensive compared to the conventional RP-HPLC. Therefore, the aim of this study was to develop a sensitive and reliable method for the determination of curcumin concentration in plasma using an RP-HPLC. Curcuma longa extract was used which contains three curcuminoids. The method started by selection of mobile phase to optimally separate the curcuminoids. The best mobile phase composition was used to analyze the plasma samples. Rat plasma was spiked with curcumin and processed for protein precipitation followed by liquid-liquid extraction of curcuminoids and an internal standard, emodin. Chromatogaphic separation of curcuminoids and emodin was achieved using a Knauer C-18 column (250 x 4.6 mm; particle size: 5µm) and a gradient program of mobile phase of three solvents, methanol -acetonitrile-1% acetic acid. A gradient elution was applied with increasing the ratio of the volume percentages of acetonitrile to acetic acid from 50/45 to 53/42 during 5 minute and thereafter elution was isocratic for 15 minute. The methanol concentration was kept constant at 5 vol-% during the whole run. The method was validated according to the FDA guidelines.The method was selective, with an excellent resolution (Rs value > 2.5). The peak shape of both curcumin and emodin were symmetric with a tailing factor of 0.9-1.1. The method linearity (correlation coefficient of 0.999) was demonstrated at 6 to 200 ng/mL. The intra and inter-day precision was 5.90-8.50% and 5.37-11.26%, respectively; the intra- and inter-day accuracy was 92.47-103.61% and 96.17-105.70%, respectively. In conclusion, the RP-HPLC method meets the validation requirements as described in the FDA guidelines and is applicable to accurately quantify curcumin concentrations as low as 6 ng/mL in rat plasma samples

BigWig and BigBed: enabling browsing of large distributed datasets

Summary: BigWig and BigBed files are compressed binary indexed files containing data at several resolutions that allow the high-performance display of next-generation sequencing experiment results in the UCSC Genome Browser. The visualization is implemented using a multi-layered software approach that takes advantage of specific capabilities of web-based protocols and Linux and UNIX operating systems files, R trees and various indexing and compression tricks. As a result, only the data needed to support the current browser view is transmitted rather than the entire file, enabling fast remote access to large distributed data sets

Target Mass Monitoring and Instrumentation in the Daya Bay Antineutrino Detectors

The Daya Bay experiment measures sin^2 2{\theta}_13 using functionally identical antineutrino detectors located at distances of 300 to 2000 meters from the Daya Bay nuclear power complex. Each detector consists of three nested fluid volumes surrounded by photomultiplier tubes. These volumes are coupled to overflow tanks on top of the detector to allow for thermal expansion of the liquid. Antineutrinos are detected through the inverse beta decay reaction on the proton-rich scintillator target. A precise and continuous measurement of the detector's central target mass is achieved by monitoring the the fluid level in the overflow tanks with cameras and ultrasonic and capacitive sensors. In addition, the monitoring system records detector temperature and levelness at multiple positions. This monitoring information allows the precise determination of the detectors' effective number of target protons during data taking. We present the design, calibration, installation and in-situ tests of the Daya Bay real-time antineutrino detector monitoring sensors and readout electronics.Comment: 22 pages, 20 figures; accepted by JINST. Changes in v2: minor revisions to incorporate editorial feedback from JINS

Process chain approach to the Bose-Hubbard model: Ground-state properties and phase diagram

We carry out a perturbative analysis, of high order in the tunneling parameter, of the ground state of the homogeneous Bose-Hubbard model in the Mott insulator phase. This is made possible by a diagrammatic process chain approach, derived from Kato's representation of the many-body perturbation series, which can be implemented numerically in a straightforward manner. We compute ground-state energies, atom-atom correlation functions, density-density correlations, and occupation number fluctuations, for one-, two-, and three-dimensional lattices with arbitrary integer filling. A phenomenological scaling behavior is found which renders the data almost independent of the filling factor. In addition, the process chain approach is employed for calculating the boundary between the Mott insulator phase and the superfluid phase with high accuracy. We also consider systems with dimensionalities d>3, thus monitoring the approach to the mean-field limit. The versatility of the method suggests further applications to other systems which are less well understood.Comment: 15 pages, 20 figure