[en] The preparation process for ²³⁸Pu radioactive source includes source manufacture, welding, fabrication, verification test. In the present work, our subjects were chosen for individual dose monitoring. For each subject, external irradiation dose monitoring determined with personal dosimeter, and internal irradiation dose monitoring analyzed with urine samples, were conducted. The experimental results showed that the personal external irradiation dose of the four subjects was less than the limiting value. No radioactivity detected in the urine samples indicated that personal internal irradiation protection during the process for the subjects was effective. (authors)

[en] The inhibitory effect of DNA topoisomerase (Top I) by isoliquiritigenin(ISO) were investigated and their interaction mechanism was evaluated using methods including UV–vis absorption, fluorescence, coupled with molecular simulation, and using the MTT method of inhibition rate of HCC tumor cell SNU475 proliferation assay, finally, the interaction of ISO with calf thymus DNA was investigated by melting measurements and molecular docking studies. It was found that isoliquiritigenin reversibly inhibited DNA Top I in a competitive manner with the concentrations of ISO resulting in 50% activity lost (IC_5_0) were estimated to be 0.178 ± 0.12 mM. Isoliquiritigenin exhibited a strong ability to quench the intrinsic fluorescence of Top I through a static quenching procedure. The positive values of enthalpy change and entropy change suggested that the binding of isoliquiritigenin to Top I was driven mainly by hydrophobic interactions. The molecular docking results revealed isoliquiritigenin actually interacted with the primary amino acid residues on the active site of Top I, and the detection results of fluorescence staining and the inhibitory effect on the growth of HCC SUN475 showed that isoliquiritigenin induced the apoptosis cells increased gradually. The interaction of ISO with DNA can cause the denaturation temperature to be increased, which indicated that the stabilization of the DNA helix was increased in the presence of ISO, which indicated that the results provide strong evidence for intercalative binding of ISO with DNA. - Highlights: • ISO reversibly inhibits TOP I activity in an A dose dependent manner. • Hydrophobic interactions play a major role in ISO–TOP I interaction. • ISO has a high affinity close to the active site pocket of TOP I. • The binding of ISO to DNA induces the stability of the structure of DNA

[en] Objective: To evaluate the diagnostic value of SPECT rCBF imaging in examining patients with olivopontocerebellar atrophy (OPCA). Methods: SPECT rCBF imaging and MRI were performed on 20 patients with OPCA. All the results of two modalities were compared with each other. Results: Hypo-perfusions of brain were identified in patients with OPCA, especially in cerebellum, brain stem and basal ganglia, and in cerebral lobes in certain cases as well. Compared with MRI, SPECT showed more extensive foci. The positive rates in SPECT and MRI were 95% and 75% respectively. Conclusions: SPECT provides a new method for the diagnosis of OPCA. SPECT rCBF imaging is a more sensitive and effective method for OPCA lesion localization comparing with MRI. A combination of these two methods (SPECT and MRI) will improve the positive rate and accuracy for the diagnosis of OPCA

[en] Eu, Tb co-doped SrAl_2Si_2O_8 luminescent materials were synthesized via a high-temperature solid-state reaction. Excitation spectra of SrAl_2Si_2O_8: Eu"2"+ gives two broad excitation bands maximizing at 270 and 330 nm, resulting from splitting Eu"2"+ energy levels in octahedral crystal field. Eu single doped SrAl_2Si_2O_8 luminescent material exhibits two emission bands at about 406 and 616 nm. Intensity of the blue emission from Eu"2"+ is always strong, compared with that of the red emission band of Eu"3"+. Reduction from Eu"3"+ to Eu"2"+ can be explained with the model of charge compensation. Blue emission in SrAl_2Si_2O_8: xEu was strengthened after incorporation of Tb, which can be explained by electron transfer from Tb"3"+ to Eu"3"+ (Tb"3"+ + Eu"3"+ → Tb"4"+ + Eu"2"+). Under 230 nm excitation, intensity of Tb"3"+ emission was nearly unchanged and that of Eu"2"+ was increased, obviously due to the delivery of more electrons to Eu"3"+. The strongest emission of Eu"2"+ in 0.09Eu/0.06Tb co-doped SrAl_2Si_2O_8 and excited at 270 and 330 nm was remarkably enhanced by about four times compared to that of 0.15Eu Single doped SrAl_2Si_2O_8. All of the results indicate that SrAl_2Si_2O_8:xEu, yTb are potential blue emitting luminescent materials for UV-LEDs. More importantly, this research may provide a new perspective in designing broad band blue luminescent materials. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

[en] Herein we report an isostructural solid solution of Mg₂(Ti_1-xSn_x)O₄:0.002Mn (0 ≤ x ≤ 1) in which cation substitution leads to the presence of two different Mn luminescence centers. When Mn sources of different valance states (MnCO₃/MnO₂/Mn₃O₄) were introduced into Mg₂TiO₄, the self-redox reaction of MnCO₃ occurred in air that can be proved by experimental results, from Mn²⁺→ Mn⁴⁺→ Mn³⁺ and eventually Mn₃O₄ can be obtained. Low valance state Mn^2+/3+ ions in Mn₃O₄ can be further oxidized to Mn⁴⁺ ions by O₂ in Mg₂TiO₄:Mn. Mn⁴⁺ red emission can be observed along with oxygen defects-induced blue emission in Mg₂(Ti_1-xSn_x)O_4:Mn (0 ≤ x<1). Eventually, the spectral emission of Mn⁴⁺ was converted to that of Mn²⁺, green emission, in Mg₂SnO₄:Mn though electrons transfer from oxygen vacancies ($V_o^{•}$) to Mn³⁺. This is the first time that compositional-tunability that induces Mn ions of different valance states luminescent behaviors and further interprets its spectral transition mechanism.

[en] Germanium 68 is mainly used for preparation of the ⁶⁸Ge-⁶⁸Ga generator and the calibration of positron emission computed tomography. The low melting point of the target material in the production reaction ⁶⁹Ga (p, 2n) ⁶⁸Ge has limited the availability of Ge-68. In order to use the existing industrial cyclotron hardware to produce Germanium 68, the method of electrodepositing gallium-nickel alloy was set up in this study. Acidic requirements were met through the preparation of the gallium-nickel alloy targets and by optimizing the plating bath composition and electrodepositing conditions, finally confirmed by adjustment of the electro-deposition process, and preparation of the gallium-nickel alloy targets with a gallium content of 75 %. After three time irradiation tests, the process was certified to produce targets of Germanium 68. This process is user-friendly, the preparation of the targets is of stable quality, and it can be applied to the cyclotron production of Germanium 68. (authors)

[en] A novel Mn²⁺ doped Li₂CdSiO₄ phosphors were synthesized in 1100 °C without reducing atmosphere. Their structure, self-reduction mechanism and luminescence properties were evaluated. Oxygen vacancies were confirmed to exist in Li₂CdSiO₄ by electron spin-resonance spectroscopy and bond volume polarizability of Li₂CdSiO₄ was calculated to prove the lattice oxygen (O3) may easily form oxygen defect (${\mathrm{V}}_{\mathrm{o}}^{\mathrm{•}}$). After different valence Mn source (MnO₂ and MnCO₃) as raw materials were built into Li₂CdSiO₄, similar emission bands with a maximal value of 515 nm appeared under 226 nm excitation and it was ascribed that energy transfer occurred from host to Mn²⁺ ions. Meanwhile, it was demonstrated that a series of redox reactions does happen from MnCO₃ to Mn₃O₄ with increasing calcination temperature. Eventually, Mn₃⁺ (Mn₃O₄) ions were reduced to Mn²⁺ through electron transfer from ${\mathrm{V}}_{\mathrm{o}}^{\mathrm{•}}$ to Mn³⁺. Furthermore, interstitials oxygen (O_i) was detected in Li₂CdSiO₄:0.02Mn sample through X-ray photoelectron spectroscopy (XPS) and the special tunnel structure may provide a suitable position to stabilize O_i in air. Direct spectroscopic evidence and the assumed mechanism have been presented for explaining these processes. This research provides a new perspective for defects induced Mn²⁺ emission in designing broad band green phosphors. More importantly, the present work further deepens the understanding of the self-reduction mechanism of Mn²⁺.

[en] In spite of the excellent optical properties of all-inorganic halide perovskite quantum dots (PQDs), they still suffer from inherent poor stability even when exposed to moisture from the atmosphere, restricting their applications, especially in white-light-emitting diodes (LEDs) and cells imaging. Here, we proposed a strategy by encapsulating the CsPbX₃ (X = Cl, Br, I) PQDs into silica nanoplates to prepare highly stable and water-soluble CsPbX₃/SiO₂ nanocomposites. First, the 120 nm monodisperse CsPbX₃/SiO₂ nanocomposites inlayed with several CsPbX₃ PQDs were fabricated via the modified Stöber method. After coating, their stability exposed in the air was largely improved for all the CsPbX₃ (X = Cl, Br, I) PQDs without changing their emission peaks and full-width at half-maximum, attributed to the suppression of the anion-exchange and decomposition. Moreover, further experiments demonstrated that the CsPbX₃/SiO₂ nanocomposites were highly water-soluble and stable in the water. Their applications in LEDs and cell imaging demonstrated their ultrastability and high biocompatibility. Therefore, this study shows the possibility of their use in photoelectric devices and biological applications. (paper)

[en] The relation between stress evolution and surface morphology during deposition of sputtered films is examined by combining kinetic Monte Carlo simulations and stress measurements. We find that the surface morphology is susceptible to an instability, which transforms from layer-by-layer growth to the formation of pillarlike columns. The gaps between these columns prevent complete densification and can lead to a network of pores in the layer. We propose that the formation of this structure changes the stress in the growing layers from compressive to tensile.

[en] Highlights: • when Sr²⁺ ions are doped into samples, the abnormal two-peak emission behavior can be achieved under 347 nm excitation. • The present work studies sites occupation of Bi³⁺ by employing the complex crystal valance bond theory calculation. • Analysis suggests that two components of emission band are ascribed to Bi³⁺ which occupies Y2/Y4 and Ba1/Ba2 sites. - Abstract: A series of Ba₃Y₄O₉:Bi³⁺ phosphors with trigonal lattice in the R3 (146) space group are investigated in the aspect of structure and luminescence. The Ba₃Y₄O₉:Bi³⁺ phosphor exhibits a promising broad yellowish-green emission peaking at 524 nm at the excitation of 347 nm. When Sr²⁺ ions are introduced into series of samples, the abnormal two-peak emission behavior centered at 412 nm and 524 nm can be observed, simultaneously. Eventually, tunable emission colors are obtained from yellowish-green to blue via controlling the ratio of Sr²⁺/Ba²⁺ content. Through calculation, the corresponding environmental factor of every Y³⁺ and Ba²⁺ site can be obtained. Analysis suggests that two components of the excitation band at 344 and 361 nm are ascribed to Bi³⁺ ions which occupies Y(2)/Y(4) and Ba(1)/Ba(2), respectively. It can be further expected that the anomalous emission of 412 nm is attributed to Bi³⁺ ions which occupies Sr(1)/Sr(2) sites when substitution occurs.