Uranium recovery via melt separation of rare earth elements and chemical oxidation

Journal of Radioanalytical and Nuclear Chemistry - Pyroprocessing of spent fuels, especially the recovery of U, improves the overall efficiency of nuclear recycling. The recovery of U/Transuranic...     

Fluorescent and pH-responsive diblock copolymer-coated core-shell CdSe/ZnS particles for a color-displaying, ratiometric pH sensor

A color distinctive, ratiometric pH sensor was demonstrated using pH responsive and fluorescent (PyMMP-b-P2VP) diblock copolymer coated CdSe/ZnS QDs. Due to the change in the P2VP conformations in response to pH change, the color of QDs in solution changes distinctly from blue to red.     

A Concise Total Synthesis of (+)‐Tetrabenazine and (+)‐α‐Dihydrotetrabenazine

Highly concise asymmetric total syntheses of (+)‐tetrabenazine ( 1 ), a drug for the treatment of chorea associated with Huntington’s disease, and of (+)‐α‐dihydrotetrabenazine ( 2 ), an active metabolite of 1 , have been accomplished. Our synthetic route features a trans‐selective enol etherification, followed by an unprecedented cation‐dependent aza‐Claisen rearrangement to establish the carbon framework and two stereogenic centers of tetrabenazine. The syntheses consist of seven steps (34 % overall yield) for (+)‐ 2 and eight steps (22 % overall yield) for (+)‐ 1 .     

Removal of rare earth elements from a U/RE ingot via a reaction with UCl3

Journal of Radioanalytical and Nuclear Chemistry - A chemical equilibrium experiment was conducted to remove rare earth (RE) elements from a U/RE ingot using UCl3 as an oxidant. Upon analysis, the...     

Biophysical characterization of the molecular orientation of an antibody-immobilized layer using secondary ion mass spectrometry

The molecular orientation of antibody layers formed on separate solid matrices (e.g., gold-coated glass substrate) was characterized by means of time-of-flight secondary ion mass spectrometry (ToF-SIMS) in static mode. For comparison, three different antibody species, IgG, F(ab')(2), and Fab, were prepared, biotinylated in random and site-directed fashions, and immobilized on distinct streptavidin-coated surfaces. ToF-SIMS analyses of each antibody layer revealed that the secondary ion intensity peaks measured at the mass-to-charge (m/z) ratio 253, 325, and 647 were unique to the site-directly immobilized antibodies. The ions in the three peaks were detected neither from the streptavidin layer nor from the randomly prepared antibody, indicating that the insolubilized antibody layers constructed in the two different manners had distinct molecular arrangements. The antibody preparations were further tested for their binding characteristics in sandwich-type immunoassays, which showed that the site-directed antibodies consistently enhanced the detection capability comparing to those randomly prepared. Based on the analytical results of both the ToF-SIMS analysis and sandwich-type immunoassays, the site-directed antibody species were immobilized on the surfaces in a more orientated manner, with their antigen binding sites exposed to the bulk solution, than when random immobilization was used.     

Heat Treatment of the Photonic Crystal Fiber

We report heat treatment of the photonic crystal fiber. As the temperature was increased, the transmission of the photonic crystal fiber was increased, unlike conventional single mode fiber. The transmission increase at short wavelength region was larger than long wavelength region for the various temperatures. After crystallization of the silica glass, the spectra of the photonic crystal fiber were just decreased at all wavelength regions, but, in case of the single mode fiber, the absorption in visible region around 450 nm increased with increasing temperature.     

OH Diffusion in Silica Glass Preform During Jacketing Process by Oxy-Hydrogen Burner

Radial distribution of OH diffusion in silica glass preform during jacketing process using a oxy-hydrogen burner was investigated by FTIR spectroscopy. The OH peaks at the jacketing boundary and the surface of the preform were found to be due to diffusion of OH incorporated from the burner.     

Photonic Crystal VCSELs

Photonic crystal vertical cavity surface emitting lasers (PC VCSELs) are reviewed. The PC VCSEL shows single-transverse-mode continuous wave operation in the entire current range with side mode suppression ratio 35-40dB. A simple 3-D plane wave expansion method is found to be very effective in analyzing the modal properties of the PC VCSELs.     

Fast gradient elution reversed-phase high-performance liquid chromatography with diode-array detection as a high-throughput screening method for drugs of abuse. I. Chromatographic conditions

A new approach for the high-throughput screening of biological samples to detect the presence of regulated intoxicants has been developed by modifying a conventional gradient elution high-performance liquid chromatograph (HPLC). The goal of this work was to improve the speed of gradient elution screening methods over current approaches by optimizing the operational parameters of both the column and the instrument without compromising the reproducibility of the retention times, which is the basis for the identification of intoxicant compounds. Most importantly, the novel instrument configuration substantially reduces the time needed to re-equilibrate the column between consecutive gradient runs, thereby reducing the total time for each analysis. The total analysis time for each gradient elution run is only 2.80 min, including 0.30 min for column re-equilibration between analyses. Retention times of standard calibration solutes are reproducible to better than 0.002 min in consecutive runs. A corrected retention index was adopted to account for day-to-day and column-to-column variations in retention time. For a set of forty-seven target compounds, the discriminating power and mean list length were found to be 0.95 and 3.26, respectively. In comparison to previous work with similar numbers of target compounds, the current approach provides an order of magnitude improvement in analysis time, and a four-fold decrease in mean list length.     

Miniature fiber-optic high temperature sensor based on a hybrid structured Fabry-Perot interferometer

A miniature Fabry-Perot (FP) interferometric fiber-optic sensor suitable for high-temperature sensing is proposed and demonstrated. The sensor head consists of two FP cavities formed by fusion splicing a short hollow-core fiber and a piece of single-mode fiber at a photonic crystal fiber in series. The reflection spectra of an implemented sensor are measured at several temperatures and analyzed in the spatial frequency domain. The experiment shows that the thermal-optic effect of the cavity material is much more appreciable than its thermal expansion. The temperature measurements up to 1000 degrees C with a step of 50 degrees C confirm that it could be applicable as a high-temperature sensor.