Application of fluorescein sodium on Cerenkov radiation energy transfer / 中华核医学与分子影像杂志

Objective To explore and evaluate the method and feasibility of applying the contrast agent fluorescein sodium to enhance the efficiency of Cerenkov radiation energy transfer (CRET).Methods Fluorescein sodium was employed as the energy transfer receptor of 18 F-FDG Cerenkov radiation (CR) to achieve stronger signal.18F-FDG was mixed with fluorescein sodium of different concentrations:0.05,0.10,0.20,1.00,2.00,4.00,8.00 mmol/L.Optical signal strength was quantified by ROI analysis.The influence of fluorescein sodium concentration on CRET efficiency and the optimal concentration that could achieve most optical signal augmentation were studied.The optimal concentration of fluorescein sodium was mixed with 1.85-11.10 MBq 18F-FDG for CLI.Linear regression was performed to investigate the range of 18F-FDG dose with most optical signal augmentation and the influence of 18F-FDG dose on CRET efficiency.A tumorbearing nude mouse was imaged after intravenous injection of 18F-FDG and then imaged again after injection of fluorescein sodium post 18 F-FDG injection.These two sets of images were compared to evaluate the CRET efficiency in vivo.Results In vitro study showed that 1.00 mmol/L fluorescein sodium was the optimal concentration for 18F-FDG dose ranging from 1.85 MBq to 11.10 MBq.The signal from 18F-FDG mixed with fluorescein sodium was 3.7 times stronger than that from 18F-FDG alone.Experiment in vivo suggested that 18F-FDG mixed with fluorescein sodium could effectively enhance the signal strength by CRET.Conclusion 18F-FDG mixed with fluorescein sodium may improve the efficiency of CRET,therefore,can enhance the signal strength,reduce the exposure time and achieve better signal to noise ratio.

A Glassy Carbon Electrode Modified with Electrochemically Reduced Graphene Oxide/Gold Nanoparticles-Chitosan Composite Film for Sensitive Determination of Uric Acid / 分析化学

Anelectrochemicallyreducedgrapheneoxide/goldnanoparticle-chitosan(ERGO/AuNP-CS) composite film modified glassy carbon electrode ( GCE) was constructed by directly electrochemical reduction of GO, and then assembly of AuNP-CS polycation on the surface. The surface morphologies of different modified electrodes including bare GCE, GCE/GO, GCE/ERGO and GCE/ERGO/AuNP-CS were characterized by scanning electron microscopy ( SEM ) . The differential pulse voltammetric behaviors of the electrodes were investigated, and the results indicated that the composite of ERGO/AuNP-CS exhibited excellent electrocatalytic oxidation activity to uric acid ( UA) molecule. In 0. 10 mol/L of phosphate buffer solution (pH=6. 5) with a scanning rate of 100 mV/s, the proposed composite film modified electrode showed a linear electrochemical response to UA in the range of 0 . 05-110 μmol/L with a detection limit of 12. 4 nmol/L ( S/N = 3 ). The electrode displayed good selectivity, reproducibility and stability in the determination of UA in human serum and urine samples with a recovery of 93 . 8%-104 . 1%. The detection results were agreed with those of conventional spectrophotometry and uricase Kit methods.

Recover soft x-ray spectrum using virtual flat response channels with filtered x-ray diode array.

A method for the recovery of soft x-ray spectra in indirect-drive inertial confinement fusion experiments is presented. Virtual detection channels with bandpass responses are obtained using linear combinations of the channel response functions of a filtered x-ray diode array and a weighted correction is introduced to improve the recovery. These virtual channels can be used to calculate radiation fluxes in some specific photon energy bands and hence to recover the spectrum of the whole photon energy range from 80 eV to 4.5 keV. Examples are listed which demonstrate the capability of this method to unfold various spectra such as Planck spectra with different radiation temperatures and to obtain x-ray flux of certain narrow energy interval.