[en] As an important radioisotope in nuclear industry and other fields, americium-241 is one of the most serious contamination concerns duo to its high radiation toxicity and long half-life. In this experiment, the biosorption of ²⁴¹Am from solution by a fungus, Saccharomyces cerevisiae (S. cerevisiae), and the effects of various experimental conditions on the biosorption and the mechanism were explored. The preliminary results showed that S. cerevisiae is a very efficient biosorbent. An average of more than 99% of the total ²⁴¹Am could be removed by S. cerevisiae of 2.1g/L (dry weight) from ²⁴¹Am solutions of 2.22MBq/L -555 MBq/L (Co). The adsorption equilibrium was achieved within 1 hour and the optimum pH ranged 1-3. The culture times of more than 16 hours were suitable and the efficient adsorption of 241Am by the S. cerevisiae could be noted. The biosorption of 241Am by the decomposed cell wall, protoplasm or cell membrane of S. cerevisiae was same efficient as by the intact fungus, but the some components of S. cerevisiae, such as protein and acylation group had obvious effect on adsorption. When the concentrations of coexistent Eu³⁺, Nd³⁺ were 100 times more than that of ²⁴¹Am, the adsorption rates would drop to 65%. However, most of the investigated acidic ions have no significant influence on the 241Am adsorption but minute change of pH value, while the saturated EDTA can strong inhibit the biosorption of ²⁴¹Am.. (authors)

[en] We present a hybrid continuous-wave, frequency-domain instrument for near-infrared spectral imaging of the female breast based on a tandem, planar scanning of one illumination optical fiber and one collection optical fiber configured in a transmission geometry. The spatial sampling rate of 25 points/cm² is increased to 400 points/cm² by postprocessing the data with a 2D cubic spline interpolation. We then apply a previously developed spatial second-derivative algorithm to an edge-corrected intensity image (N-image) to enhance the visibility and resolution of optical inhomogeneities in breast tissue such as blood vessels and tumors. The spectral data at each image pixel consist of 515-point spectra over the 650-900 nm wavelength range, thus featuring a spectral density of two data points per nanometer. We process the measured spectra with a paired-wavelength spectral analysis method to quantify the oxygen saturation of detected optical inhomogeneities, under the assumption that they feature a locally higher hemoglobin concentration. Our initial measurements on two healthy human subjects have generated high-resolution optical mammograms displaying a network of blood vessels with values of hemoglobin saturation typically falling within the 60%-95% range, which is physiologically reasonable. This approach to spectral imaging and oximetry of the breast has the potential to efficiently exploit the high intrinsic contrast provided by hemoglobin in breast tissue and to contribute a useful tool in the detection, diagnosis, and monitoring of breast pathologies

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[en] Thermosensitive PVA-g-NIPAAm copolymers were prepared by graft copolymerization of N-isopropylacrylamide (NIPAAm) onto poly (vinyl alcohol) (PVA) in homogeneous system of dimethyl sulfoxide (DMSO) by ⁶⁰Co-γ irradiation at room temperature. The factors of affecting the grafting yield, such as radiation dose, dose rate, acid concentration, were investigated. It was found that the grafting yield was increased with dose up to 30 kGy, but decreased slightly with dose rate from 61.2 to 50.1 Gy/min. The acid concentration also had influence on the grafting yield. Then the hydrogel of PVA-g-NIPAAm copolymer was made through a freezing-thawing process. The PVA-g-NIPAAm hydrogel exhibited obvious thermal sensitivity, which was observed from the differences of swelling behavior in water at different temperatures (below or above LCST). In addition, the release of Methylene Blue (MB) from this kind of hydrogel was studied. The release rate of MB from PVA-g-NIPAAm copolymer hydrogel at 48 deg. C was faster than that at 15 deg. C due to the shrinkage of the hydrogel at 48 deg. C. (author)

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[en] In this paper, we present a study of magnetocaloric effect in the colossal magnetoresistance material (La_0.5Gd_0.2)Sr_0.3MnO₃. From the measurements of isothermal magnetization at different temperatures, we have discovered a large magnetic entropy change with a broad peak around Curie temperature (270.5 K) in (La_0.5Gd_0.2)Sr_0.3MnO₃ polycrystalline sample. Moreover, the maximum of magnetic entropy change exhibits a nearly linear dependence with applied high magnetic field. These results suggest that this material is a suitable candidate as working substance in magnetic refrigeration near room temperature

[en] In this work, we investigate the one-loop QCD correction to top pair production in the littlest Higgs model with T-parity at the LHC. We calculate the relative correction of the top pair production cross-section and top-antitop spin correlation at the LHC for $\sqrt{s}=8,14\text{TeV}$. We find that the relative corrections of top pair production cross-section can reach about $-<!--\; ???\; -->0.35\mathrm{\%<!--\; \%\; -->}$, and the top-antitop spin correlation can reach $1.7\mathrm{\%<!--\; \%\; -->}(2\mathrm{\%<!--\; \%\; -->})$ at the 8(14) TeV LHC in the favorable parameter space. (letter)

[en] Some recent developments of radiotherapeutic drug labelled with ²¹¹At, such as ²¹¹At-colloids, ²¹¹At labelled compounds, ²¹¹At labelled monoclonal antibodies and fragments, are presented. Additionally, its situation, problems and prospect are discussed. (49 refs.)