A multielement masking method using magnesium hydroxide coprecipitation for the selective determination of lead in water samples by differential pulse anodic stripping voltammetry.

We present a new multielement masking method using magnesium hydroxide coprecipitation for the selective determination of Pb by differential pulse anodic stripping voltammetry (DPASV). The recovery of Pb in the masking method was over 95%, while interfering ions (Cd(2+), Co(2+), Cu(2+), Fe(3+), Mn(2+), and Ni(2+)) could be removed at 100% from the analytical sample. A linear regression was obtained in the Pb concentration from 10 to 1000 microg kg(-1) in the existence of 100 microg kg(-1) of the interfering ions. When this method was applied to the determination of Pb in a natural water-standard reference material (NIST 1640), the determined value for Pb in this work (25.4 +/- 4.1 microg kg(-1)) almost agreed with the certified value (27.89 +/- 0.14 microg kg(-1)).     

Pionic atom factory project in the RIBF

We are preparing for a high resolution spectroscopy of the 1s and 2s pionic states of ¹²¹Sn in the ¹²²Sn(d,³He) reaction at the incident deuteron energy of ~500 MeV. The measurement will provide accurate information on the strong interaction between the pion and the nucleus, which leads to quantitative determination of the magnitude of the quark condensate at the normal nuclear density.     

Concentration dependences of dielectric properties at 105Hz and 106Hz for aqueous solutions of hydroxypropyl cellulose

The concentration dependences of dielectric properties measured at 10⁵ Hz and 10⁶ Hz are reported for aqueous solutions of hydroxypropyl cellulose. Phase behaviour of the solutions was also observed with a polarizing optical microscope. For solutions with concentrations well above 40 wt %, polydomain textures, including the banded texture, were observed after a prehistory of deformation. No significant discontinuous changes in the dielectric constant, ε_r', and loss factor, ε_r', were found at the concentrations around the onset of the isotropic-cholesteric phase transition and in the biphasic region. In contrast, the steeper changes in ε_r' and ε_r' were found at the critical concentration for the fully developed cholesteric phase transition with the polydomain textures.     

Synthesis of a nitrogen analogue of salacinol and its alpha-glucosidase inhibitory activity.

A nitrogen analogue 4 of the naturally occurring sulfonium ion salacinol (1), a potent alpha-glucosidase inhibitor isolated from the Ayruvedic medicine Salacia reticulata, was synthesized and its inhibitory activity against alpha-glucosidase tested. Substitution of the sulfur atom in 1 with a nitrogen reduced the activity considerably. The solid-state stereostructure of the related compound (5) was determined on the basis of single crystal X-ray measurement.     

Carotenoids extraction from Japanese persimmon (Hachiya-kaki) peels by supercritical CO(2) with ethanol.

The extraction of carotenoids from Japanese persimmon peels by supercritical fluid extraction (SFE), of which the solvent was CO(2), was performed. In order to enhance the yield and selectivity of the extraction, some portion of ethanol (5 - 20 mol%) was added as an entrainer. The extraction temperature ranged from 313 to 353 K and the pressure was 30 MPa. The effect of temperature on the extraction yield of carotenoids was investigated at 10 mol% of the ethanol concentration in the extraction solvent, and a suitable temperature was found to be 333 K among the temperatures studied with respect to the carotenoid yield. With increasing the entrainer amount from 0 to 10 mol% at a constant temperature (333 K), the carotenoid yield in the extraction was improved, whereas the selectivity of the extracted carotenoids was drastically depressed. We also conducted qualitative and quantitative analyses for the carotenoid components in the extract by HPLC, and analyzed the extraction behavior of each individual carotenoid (alpha-carotene, beta-carotene, beta-cryptoxanthin, lycopene, lutein, and zeaxanthin). The selectivity of each carotenoid changed with the elapsed time and its time evolution was dependent on the carotenoid component, indicating that the location profile and the content can be important factors to understand the SFE behavior of each carotenoid in persimmon peels.     

Near-infrared emissions and quantum efficiencies in Tm-doped heavy metal gallate glasses for S- and U-band amplifiers and 1.8 μm infrared laser

Intense 1.8 μm and efficient 1.48 μm infrared emissions have been recorded in Tm³⁺-doped alkali-barium-bismuth-gallate (LKBBG) glasses with low phonon energies under the excitation of 792 nm diode laser. The maximum emission cross-sections for 1.8 and 1.48 μm emission bands are derived to be 6.26×10⁻²¹ and 3.34×10⁻²¹ cm², respectively, and the peak values are much higher than those in Tm³⁺-doped ZBLAN glass. In low-concentration doping, the full-widths at half-maximum (FWHMs) of the two emission bands are 223 and 122 nm, and the quantum efficiencies of the ³F₄ and ³H₄ levels are proved to be ∼100% and 86%, respectively. When the doping concentration increases to 1 wt%, the quantum efficiency of the ³H₄ level is reduced to 60% due to the cross-relaxation processes in high-concentration doping. Efficient 1.8 μm infrared emission in Er³⁺/Tm³⁺-codoped LKBBG glass has also been achieved under the excitation of 970 nm diode laser, and the probability and the efficiency of non-radiative energy transfer from Er³⁺ to Tm³⁺ are as high as 354 s⁻¹ and 58.4%, respectively. Efficient and broad 1.8 and 1.48 μm infrared emission bands indicate that Tm³⁺-doped LKBBG glasses are suitable materials in developing S- and U-band amplifiers and 1.8 μm infrared laser.     

Hepatocellular lesions with increased iron uptake on superparamagnetic iron oxide-enhanced magnetic resonance imaging in cirrhosis or chronic hepatitis: comparison of four magnetic resonance sequences for lesion conspicuity

Purpose

The aim of this study was to determine the adequate MR sequence for the lesion conspicuity of hepatocellular lesions with increased iron uptake on superparamagnetic iron oxide (SPIO)-enhanced MRI.

Materials and Methods

SPIO-enhanced MRI was performed using a 1.5-T system. Among 25 patients with hypovascular hepatocellular nodules on contrast-enhanced dynamic CT (no early enhancement at arterial phase and hypoattenuation at equilibrium phase), 39 lesions with increased iron uptake on SPIO-enhanced MRI were evaluated. SPIO-enhanced MRI included (1) T1-weighted in-phase gradient recalled echo (GRE) images, (2) T2-weighted fast spin echo (FSE) images, (3) T2*-weighted GRE with moderate TE (7 ms) and (4) long TE (12 ms). The lesion-to-liver contrast-to-noise ratios of the hepatocellular nodule and the signal-to-noise ratio (SNR) of the hepatic parenchyma were calculated by one radiologist for a quantitative assessment. MR images were reviewed retrospectively by two independent radiologists to compare the subjective lesion conspicuity in each image set based on a four-point rating scale.

Result

The mean lesion-to-liver contrast-to-noise ratios with T2*-weighted GRE with moderate TE (7 ms) was highest (5.79±3.71) and was significantly higher than those with T1-weighted, in-phase images (3.79±3.23, P<.01), T2-weighted images (2.72±1.52, P<.001) and T2*-weighted GRE with long TE (12 ms) (3.93±2.69, P<.05). The subjective rating of lesion conspicuity was best on the T2*-weighted GRE with moderate TE (7 ms), followed by that on the T2*-weighted GRE with moderate TE (7 ms; P<.05).

Conclusion

T2*-weighted GRE sequence with moderate TE (7 ms) showed high lesion-to-liver contrast-to-noise ratios in hepatocellular lesions with increased iron uptake on SPIO-enhanced MRI, indicating better lesion conspicuity of hypointense hepatocellular nodules in cirrhosis or chronic hepatitis.