[en] MoS₂ particles of uniform size (ca. 70 nm) consisting of random and loosely stacked layers have been synthesized from hydrazine solution with (NH₄)₂Mo₃S₁₃ as the precursor at 180 deg. C for 16 h under hydrothermal conditions. The particles were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and high-resolution transmission electron microscopy (HREM). The influences of reaction conditions are discussed while a mechanism is proposed to explain the formation of this peculiar morphology

[en] Phosphors of Re_2TeO_6 (Re = La, Gd, and Lu) tri-doped with Yb"3"+, Tm"3"+ and Ho"3"+ ions have been synthesized by the solid state reactions. The crystal structures have been characterized by powder XRD measurement. The SEM images have shown the average particle sizes of the phosphors can be controlled within 1 micron. Upconversion luminescences were investigated under the excitation of 976 nm laser diode. The upconversion processes were explained based on the pump dependence of upconversion emission intensity. The light color was studied in the framework of 1931 CIE diagram. The three systems have shown nice tunabilities by changing the pump intensity and rare earth ions concentration. By properly adjusting the concentration of Tm"3"+ ions white upconversion luminescence can be realized in all the three tri-doped systems. Results indicated that these phosphors have potential applications in the upconversion based white lighting and optoelectronic devices. - Highlights: • Upconversions of Re_2TeO_6 (Re = La, Gd, and Lu) tri-doped with Yb"3"+, Tm"3"+, and Ho"3"+ were investigated. • The light colors can be well tuned in the white region via adjusting the pump power and Tm"3"+ concentration. • The phosphors are potentials for white lighting and optoelectronic devices.

[en] The structural stability, electronic structure, elasticity, and optical properties of four types of monolayer BC₂N have been investigated from first principles using calculation based on density functional theory. The results show that the structural stability of BC₂N increases with the number of C–C and B–N bonds. By calculating the two-dimensional Young's modulus, shear modulus, Poisson's ratio, and shear anisotropic factors in different directions, four structures present various anisotropies and the most stable structure is almost isotropic. For C-type BC₂N, the values of two-dimensional Young's modulus, shear modulus, and bulk modulus (309, 128, 195 GPa m⁻¹), are smaller than those of graphene (343, 151, 208) but bigger than those of h-BN (286, 185, 116). Furthermore, the dielectric function, refractive index, reflectivity, absorption coefficient, and energy loss spectrum are also calculated to investigate the mechanism underpinning the optical transitions in BC₂N, revealing monolayer BC₂N as a candidate window material. - Graphical abstract: Schematic diagram of BC₂N under the biaxial tensile strain. Changes in the valence-band top and the conduction-band bottom of BC₂N with increasing strain.

[en] Recently, black phosphorus (BP), a new type of 2D material combining advantages of graphene and transition metal dichalcogenides, is of great concern. Investigations show that many excellent properties of black phosphorus are layer-dependent. In this paper, the effects of layer number on the band structure, density of states, optical properties of BP have been studied by using the first-principles calculations based on density function theory (DFT). Based on comparative analysis of band structure and density of states, it is found that band gap decreases with the increase of layer number in few-layer BP because of the splitting of energy bands induced by the inter-layer interactions. The analysis of optical properties shows that the static refractive index and the static reflectivity increase with the increase of the number of layers. Meanwhile, the reflection peaks of each layer of BP are located in the ultraviolet band. The absorption of BP to light covers the range from visible light to ultraviolet region. The variation trends of the dielectric function, refractivity, reflectivity, absorption, loss function and conductivity of BP are further analyzed on the basis of band structure and partial density of states (PDOS), which provides a useful theoretical foundation for the photoelectric application of BP. (authors)

[en] The plan to repair and reinforce the underground inclined channel of a uranium tailings dam and the application of PCC material in the project are introduced in detail. (authors)

[en] Highlights: • Ce-doped SiO₂@TiO₂ nanocomposite was prepared by flow-together neutralisation process. • The prepared samples showed the superior visible light photocatalytic activity. • The Ce could preserve large surface area of sample even annealed at 800 °C. • The sample had better dispersibility and smaller size than un-doped TiO₂. • The weight fraction of rutile phase nearly invariable with increasing calcination temperature. -- Abstract: SiO₂@TiO₂ nanoparticles doped with the different contents of Ce were prepared by a flow-together neutralisation process. The result of FT-IR showed that the Ti–O–Si bond was formed at the interface of the coating layer. The XRD data proved that the presence of Ce in SiO₂@TiO₂ could inhibit the phase transformation from anatase to rutile and enhance the thermal stability. The TEM images demonstrated that TiO₂ coated with silica had smaller particle size, uniform size distribution and polished surface. The absorption spectra indicated an extension of light absorption into the visible light region for the as-prepared samples, and the electron–hole recombination could be effectively inhibited. The effects of the Ce content on the photocatalytic activity were investigated by the photodegradation of methyl orange irradiated by visible light. The results showed that the nanocomposite with 5 mol% Ce had the best ability of photo-degradation. The degradation efficiency could reach to 93.3% after reaction for 10 min, which was more efficient than that of undoped SiO₂@TiO₂ (47.0%). For pure P25, however, the photodegradation of MO could hardly be observed under the same condition

[en] Objective: To investigate the effect of interventional treatment with p53 on the invasion and metastasis of VX2 liver tumor in experimental rabbits. Methods: VX2 carcinoma cells were surgically implanted into the left hepatic lobe in 48 New Zealand white rabbits, and the rabbit hepatic carcinoma models were thus established. The rabbits were randomly divided into 4 groups with 12 rabbits in each group. After hepatic arterial catheterization was completed physiological saline (control group), Lipiodol (Group A), Ad-p53 (Group B) and Lipiodol+Ad-p53 (Group C) were respectively infused into the rabbits of four groups via common hepatic artery. One week after the procedure the rabbits were sacrificed and the livers were removed for the determination of matrix metalloprotein-2 (MMP-2), proliferating cell nuclear antigen (PCNA) and vascular endothelial growth factor (VEGF) of the tumor with immunohistochemistry technique. Results: The tumor growth in study groups (group A, B and C) was markedly suppressed, which was significantly different in comparison with that in control group (P < 0.05). In group A the positive rates of MMP-2, PCNA were slightly lower,while the positive rate of VEGF was slightly higher, than that in control group although the difference was of no significance (P > 0.05). The positive rates of MMP-2, PCNA and VEGF in group B and C were significantly lower than those in control group (P < 0.05). The positive rates of MMP-2, PCNA and VEGF of the rabbits with metastasis were markedly higher than those without metastasis(P < 0.05). MMP-2 bore a certain relationship with VEGF and PCNA (P < 0.05). Conclusion: The increase of the positive rates of MMP-2, PCNA and VEGF indicates that the tumor possesses higher possibility for developing metastasis, proliferation and vascular formation. The interventional treatment with Adp53 or Lipiodol+Ad-p53 can inhibit the growth, metastasis and vascular formation of VX2 liver tumor in experimental rabbits. (J Intervent Radiol, 2010, 19 : 800-804) (authors)

[en] Objectives: To investigate the feasibility of the quantitative analysis parameters of dynamic contrast-enhanced MRI (DCE-MRI) in the diagnosis of prostate cancer and to correlate K^trans, V_e and k_ep with histological grade (Gleason score) and serum prostate specific antigen (PSA). Methods: MR examinations were performed in 38 patients confirmed by biopsy. ROI were drawn on areas of cancerous foci, noncancerous foci in the peripheral zone and central gland to measure the values of K^trans, V_e and k_ep. The values of the three parameters in different tissue were compared with ANOVA. The correlations between the pharmacokinetic parameters and Gleason score, PSA were assessed with Pearson, correlation. Results: The K^trans, V_e, k_ep values of cancerous foci were (0.35±0.26)/min, (0.185±0.080), (1.42±0.53 )/min, respectively, while (0.07±0.05)/min, (0.040±0.024), (0.50±0.18)/min for noncancerous foci in the peripheral zone and (0.19±0.06)/min, (0.161±0.062), (0.94±0.25)/min for noncancerous foci in the central gland, respectively. The differences between the three parameters of cancerous foci, noncancerous foci in the peripheral zone and central gland were statistically significant (F=16.267, 44.084, 36.095, respectively; P<0.01). No significant correlations were found between any parameter and either Gleason score or PSA (r=0.279, 0.069, 0.109, -0.175, -0.067, 0.137, respectively; P> 0.05). Conclusion: Quantitative analysis parameters of DCE-MRI are feasible in diagnosing prostate cancer. They may be useful in differentiating prostate cancer from benign prostatic diseases. (authors)

[en] Objective: Brain blood flow SPECT perfusion can detect changes in brain blood flow. The obiective of this study was to explore the clinical value of SPECT perfusion imaging in brain ischemic injury due to traumatic at before and after hyperbaric oxygen (HBO)treatment.Methods: Sixty-five cases of secondary ischemic brain injury patients were randomly divided into two groups. One was with HBO treatment group and the other was with conventional treatment. All had brain perfusion SPECT at before and after treatment. Computer region of interest (ROI)technology was applied in the cross-sectional images using lo-cat mirror ratio (Ra) method to determine cerebral ischemic lesions. The t-test was used to analyze the quantitative data. It would be considered as abnormal if the brain perfusion SPECT reduce Ra ≤ 0.9 aftertreatment. Results: In HBO treatment group.regional cerebral blood flow (rCBF) before and after treatment to reduce the district Ra values were 0.58 ± 0.1l and 0.82 ± 0.12 (t=7.327, P<0.01). In con-ventional treatment group. Rcbf before and after treatment to reduce the district Ra values were 0.6l ± 0.13 and 0.73 ± 0.12 (t=2.153. P=0.038). IncreaSed Rcbf at ischemic lesions in HBO treatment group was 0.24 ± 0.08 and was 0.12 ± 0.06 for conventional treatment group (t=2.571. P=0.015). Conclusions: Brain SPECT imaging could sensitively reflect the rCBF before and after treatment and was considered to be useful for therapeutic monitoring of HBO treatment efficacy. (authors)

[en] BSA/Fe₃O₄ magnetic composite microspheres with high saturation magnetization and paramagnetic property were prepared via inverse emulsion technology at room temperature, bovine serum albumin (BSA, 60 KD), magnetic nanoparticles (Fe₃O₄) and glutaraldehyde as macromonomer, inorganic particles and cross-linking agent, respectively. Fourier transform infrared (FTIR), scanning electron microscope (SEM), metalloscope, and particle size analyzer were used to characterize morphology and structure of composite microspheres. Vibrating sample magnetometer (VSM) and thermogravimetric analysis (TGA) were used to test magnetic properties of the synthesized samples, adsorption capacity of microspheres was determined by ultraviolet spectrophotometer (UV). The results showed that BSA/Fe₃O₄ microspheres were 43 μm with relatively narrow particle size distribution, perfect sphere-shaped morphologies, superparamagnetism with a saturation magnetization of 11 emu/g, and high magnetic content with a value of 57.29%. The main factors influencing properties of microspheres including raw material ratio, the amount of emulsifier and cross-linking agent, agitation speed were investigated and optimized. Furthermore, these microspheres accompanying with high separable and reusable efficient may have great potential application in the field of separation, in particular, removal of antibiotics. Adsorption capacities of the microspheres of four different kinds of antibiotics (erythromycin, streptomycin, tetracycline and chloramphenicol) ranging from 69.35 mg/g to 147.83 mg/g were obtained, and Langmuir isotherm model coincided with equilibrium data than that of the Freundlich model. - Highlights: • BSA/Fe₃O₄ microspheres with high saturation magnetization were prepared. • BSA/Fe₃O₄ microspheres for the removal of antibiotics are proposed. • The obtained results have significant importance in environmental processes