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In this study, we present a simple ultraviolet (UV) light photodiode by transferring a layer of graphene film on single-crystal ZnO substrate. The as-fabricated heterojunction exhibited typical rectifying behavior, with a Schottky barrier height of 0.623 eV. Further optoelectronic characterization revealed that the graphene-ZnO Schottky junction photodiode displayed obvious sensitivity to 365-nm light illumination with good reproducibility. The responsivity and photoconductive gain were estimated to be 3×104 A/W and 105, respectively, which were much higher than other ZnO nanostructure-based devices. In addition, it was found that the on/off ratio of the present device can be considerably improved from 2.09 to 12.1, when the device was passivated by a layer of AlOx film. These results suggest that the present simply structured graphene-ZnO UV photodiode may find potential application in future optoelectronic devices.

To investigate the suppressive effects of xanthatin on glioma growth in a nude mouse xenograft model and rat orthotopic implantation model using magnetic resonance imaging (MRI) to dynamically monitor the antitumour growth and antiangiogenesis effects of xanthatin. The nude mouse xenograft tumour model and rat orthotopic implantation model were established to observe the antitumour effects of xanthatin in vivo. In the rat orthotopic implanted tumour model, MRI scanning was used to dynamically monitor the antitumour growth effect and evaluate the antiangiogenesis effect of xanthatin. We found that xanthatin at a dose of 0.4 mg/10 g dramatically decreased the growth of xenograft tumours in nude mice. The antiangiogenesis effect of xanthatin C6 glioma was evaluated by dynamic contrast-enhanced (DCE) MRI via comparison of the volume transfer constant (Ktrans ) value, a parameter that reflects vessel permeability. We found that xanthatin at the doses of 8 and 16 mg/kg significantly decreased the Ktrans value, which suggests that xanthatin has antiangiogenesis effects. These data demonstrate the suppressive effects of xanthatin on C6 glioma occur via antiangiogenesis. Meanwhile, this study also provides evidence for the application of quantitative parameters of DCE-MRI for dynamically evaluating the growth and angiogenesis of intracranial tumours and for experimental and clinical research. [ABSTRACT FROM AUTHOR]

Purpose: To investigate whether the genu of the corpus callosum is involved in patients with clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) type I. Methods: Twenty-three cases of clinically confirmed MERS I were analyzed retrospectively, and MRI features of the lesion were observed. The apparent diffusion coefficient (ADC) values of the same region of interests in lesions at the splenium and genu of the corpus callosum were measured before and after treatment (i.e., four groups), and the average ADC values were calculated. Paired t-tests were used to compare the ADC values of lesions in the splenium and genu before and after treatment. Independent sample t-tests were used to compare the values in the splenium and genu after treatment. Results: The mean ADC values of the splenium before and after treatment were 0.448 ± 0.124 and 0.790 ± 0.070 × 10-3 mm²/s, respectively, showing significant difference (P < 0.01). The mean ADC values in the genu before and after treatment were 0.783 ± 0.067 and 0.829 ± 0.070 × 10-3 mm²/s, respectively, also showing significant difference (P < 0.01). There was no significant difference in the ADC values between the splenium and genu after treatment (P > 0.05). Conclusion: The genu showed a slight restriction in diffusion in the acute stage of type I MERS. After treatment, this diffusion restriction diminished as it typically does in the splenium. Our results indicate that the pathology in MERS extends well beyond the visible lesions. [ABSTRACT FROM AUTHOR]

Nanostructure-based materials for multimodal imaging have attracted great attentions. Here we report a new formulation integrated gadolinium (Gd) and magnetite (Fe3O4) nanoparticles as magnetic resonance (MR) imaging contrast agent at both T1 mode and T2 mode. Polyetherimide coated iron oxide (Fe3O4@PEI) nanoparticles were first synthesized and then conjugated to diethylenetriamine pentaacetic acid (DTPA), which further chelated with Gd3+ ions (Fe3O4@PEI@DTPA-Gd). Both phantom and MR studies showed Fe3O4@PEI@DTPA-Gd nanocomposites could be applied in two modes (r1 = 4.7 mM−1 s−1, r2 = 131.82 mM−1 s−1). MTT and fluorescent staining results also suggested that the nanocomposites had good biocompatibility. Besides, Fe3O4@PEI@DTPA-Gd nanocomposites exhibited high entrap efficiency when the mass ratio of nanocomposites to DNA was up to 30:1. The in vitro gene transfection ability was also evidenced. Therefore, Fe3O4@PEI@DTPA-Gd nanocomposites can be employed as a potential candidate for MRI guided clinical diagnosis and gene delivery guided therapy. [ABSTRACT FROM AUTHOR]