Influential Metrics Estimation and Dynamic Frequency Selection Based on Two-Dimensional Mapping for JPEG-Reversible Data Hiding.

JPEG Reversible Data Hiding (RDH) is a method designed to extract hidden data from a marked image and perfectly restore the image to its original JPEG form. However, while existing RDH methods adaptively manage the visual distortion caused by embedded data, they often neglect the concurrent increase in file size. In rectifying this oversight, we have designed a new JPEG RDH scheme that addresses all influential metrics during the embedding phase and a dynamic frequency selection strategy with recoverable frequency order after data embedding. The process initiates with a pre-processing phase of blocks and the subsequent selection of frequencies. Utilizing a two-dimensional (2D) mapping strategy, we then compute the visual distortion and file size increment (FSI) for each image block by examining non-zero alternating current (AC) coefficient pairs (NZACPs) and their corresponding run lengths. Finally, we select appropriate block groups based on the influential metrics of each block group and proceed with data embedding by 2D histogram shifting (HS). Extensive experimentation demonstrates how our method's efficiently and consistently outperformed existing techniques with a superior peak signal-to-noise Ratio (PSNR) and optimized FSI.

Development of a LC-MS/MS method for the estimation of clinofibrate in human urine.

A highly sensitive and rapid liquid chromatography-tandem mass spectrometry method was developed for the determination of clinofibrate in human urine. The analyte and IS were extracted through a simple protein precipitation by the mixture of acetonitrile and 1 mol/L hydrochloric acid (95:5, v/v) and separated on an Inspire C18 (150 mm x 4.6 mm I.D., 5 µm particle size) column using isocratic elution with methanol and water containing 0.1% formic acid and 10 mM ammonium acetate (90:10, v/v). Mass spectrometric detection was performed in electrospray positive ionization MRM mode. The mass transition was m/z 486.3-->175.0 for clinofibrate and m/z 361.1-->233.1 for IS, respectively. The flow rate was 0.6 mL/min and the column oven temperature was set at 35 °C. The total run time was 6.5 min. Good linear relationships were obtained for all analytes over the concentrations ranging of 0.1002-10.02 µg/mL (r2 = 0.9991) and the limit of quantification was 0.1002 µg/mL. The extraction recovery was larger than 87.4% and intra- and inter-batch precision and accuracy with RSD were all less than 6.5%. The total amount of unchanged clinofibrate excreted in urine was less than 0.34%. This method was successfully applied to the pharmacokinetic study of clinofibrate in human urine.

Synthesis, radioprotective activity and pharmacokinetics characteristic of a new stable nitronyl nitroxyl radical-NIT2011.

A new stable nitronyl nitroxyl radical NIT2011 was synthesized and characterized. The radioprotective effect and pharmacokinetics profiles of NIT2011 were investigated. The results showed that when irradiation exposure dose was 6.5 Gy gama radiation, the survival rate in the irradiation-only group was 20% on 30th day. The survival rate was 70%, 80%, and 90% on 30th day when mice were pretreated with 0.25, 0.5 and 1.0 mmol/kg NIT2011, respectively. The pretreatment of NIT2011 increased number of spleen colonies, the numbers of bone marrow cells and protein level in bone marrow cells. Pretreatment with NIT2011 prior to radiation exposure increased the plasma SOD (superoxide dismutase) activity. 24 h after irradiation exposure, level of plasma MDA (malondialdehyde) in irradiation-only mice was 14.8 ± 2.8 nmol/mL, level of plasma MDA in NIT2011 (1 mmol/kg) pretreated mice was 9.8 ± 2.0 nmol/mL. Three days after irradiation exposure, the micronucleus ratio in irradiation-only mice is 40.2 ± 3.6, the micronucleus ratio in NIT2011 (1 mmol/kg) pretreated mice was 11.7 ± 1.2. NIT2011 was easily absorbed in mice after it was oral administrated. Compared with the intraperitoneal injection, the relative oral bioavailability of the NIT2011 was 27.5% in mice. The LD50 of NIT2011 was 1510 mg/kg in mice by oral administration. Thus, NIT2011 has potential in being developed as an oral dosage form, safe and effective radioprotective agent.