S. Dai

Ningbo University, Ning-po, Zhejiang Sheng, China

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Publications (12)22.23 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The farnesoid X receptor (FXR) is a member of the nuclear receptor superfamily that is highly expressed in liver, kidney, adrenal gland, and intestine. It plays an important role in regulating the progression of several cancers including hepatocellular carcinoma (HCC). So it is necessary to study the regulation of FXR. In this study, we found that the expression of miR-421 was inversely correlated with FXR protein level in HCC cell lines. Treatment with miR-421 mimic repressed FXR translation. The reporter assay revealed that miR-421 targeted 3' untranslated region of human FXR mRNA. Furthermore, downregulation of FXR by miR-421 promoted the proliferation, migration, and invasion of HCC cells. These results suggest that miR-421 may serve as a novel molecular target for manipulating FXR expression in hepatocyte and for the treatment of HCC.
    Molecular Cancer Research 03/2012; 10(4):516-22. · 4.35 Impact Factor
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    ABSTRACT: A systematic series of (Ge15Ga10Te75)1−x(CsI)x (x=0, 5, 10, 15 at%) far infrared transmitting chalcohalide glasses were prepared by the traditional melt-quenching method. The physical, thermal and optical properties were determined. The allowed direct transition and indirect transition of samples were calculated according to the Tauc equation. The results show that glass transition temperatures (Tg) were in the range 133–175 °C, with ΔT values between 81 and 130 °C. The highest values of metallization criterion (0.244) and energy gap (1.191 eV) were obtained for (Ge15Ga10Te75)85(CsI)15. When the dissolved amount of CsI increased from 0 to 15 at%, the direct optical band gap and indirect optical band gap were in the ranges 0.629–1.075 eV and 0.438–0.524 eV, respectively. The Ge–Ga–Te–CsI glasses have an effective transmission window between 1.7 and 25 μm, encompassing the region of interest for bio-sensing applications.
    Journal of Physics and Chemistry of Solids 01/2011; · 1.53 Impact Factor
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    ABSTRACT: Soluble APRIL (sAPRIL), the active form of a proliferation-inducing ligand (APRIL), is implicated in the proliferation of tumor cells. Suppressing APRIL function has been considered as a potential strategy for the therapy of APRIL-associated tumors. In the present study, we generated human sAPRIL and its two mutants, Gln187-D-sAPRIL (Gln187 deleted) and Gly187-sAPRIL (Gln187 replaced by Gly). In vitro experiments showed that the two mutants had similar specific binding capacity to lung carcinoma A549 cells compared to the wild-type sAPRIL, and both, especially Gly187-sAPRIL, exhibited significant antagonistic effect on sAPRIL-induced tumor cell proliferation in a dose-dependent manner, which might be predominantly mediated by blocking sAPRIL-induced MEK and ERK phosphorylation but not p38MAPK or JNK signaling. In vivo experiments with nude mice bearing A549 cell-derived xenograft tumor showed that only the Gly187-sAPRIL mutant could significantly suppress the tumor growth. These results suggest that Gln187 may be a crucial amino acid in APRIL-mediated tumor cell proliferation via the MEK-ERK signaling pathway and that the sAPRIL mutants may serve as novel potential antagonists of APRIL for the therapy of APRIL-associated cancers.
    Acta biochimica Polonica 12/2009; 56(4):703-10. · 1.19 Impact Factor
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    ABSTRACT: In this paper, the methods of preparation of Ge-Se-Sb glasses with low impurity content were developed, and a large Ge-Sb-Se glass rod (phi85×80mm) with good quality was obtained. The physical and optical properties of the glass were measured. The optical homogeneity (Deltan) at 2mum at different places inside the same bulk was less +/-2×10-4. In order to accurately evaluate the infrared resolution of our prepared glass, a lens of f 19mm F/#1.3 was used to evalue its modulation transfer function (MTF) performance. The MTF value at 20cycles/mm for 20°C was 0.52. The area under MTF curve covers 82.466% of the image space, and has a value of 21.8 cycles/mm.
    Proc SPIE 07/2009;
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    ABSTRACT: The B2O3 component was introduced into Er3+/Ce3+ co-doped TeO2–ZnO–Na2O–Nb2O5 glass to improve energy transfer rate of Er3+:4I11/2→Ce3+:2F5/2 phonon-assisted cross-relaxation process. With the 6 mol% substitution of B2O3 for TeO2, the energy transfer rate increased from 1300 to 1831 s−1 and the fluorescence intensity increased by about 13.4%. However, the more B2O3 substitution in the same glass system reduced the quantum efficiency of Er3+:4I13/2→4I15/2 transition due to the higher OH− group concentration. The results show that an appropriate amount of B2O3 component can be used to improve the phonon-assisted energy transfer rate and enhance 1.53 μm fluorescence emission by increasing the phonon energy of host glass. The effect of B2O3 on the energy transfer process, the lifetimes of the 4I11/2 and 4I13/2 levels, and the upconversion emission have also been investigated.
    Journal of Luminescence 01/2009; 129:1-5. · 2.14 Impact Factor
  • X. Wang, Q. Nie, T. Xu, X. Shen, S. Dai, N. Gai, Y. Zhou
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    ABSTRACT: A kind of novel fluorescence which possesses a potential application in wide-band optical amplifying is reported in this paper. With 975-nm LD laser pumping and Yb3+-assisted energy transferring, the fluorescence of Tm3+in the tellurite glass can be measured with emission spectra in 1.4- and 1.6- μm bands, which would be continued to the 1.53 μm of the Er3+. The full-width at half-maximum (FWHM) is 170 nm(110+60110+60 nm), and the lifetimes come up to 0.66 and 1.46 ms. Then, an interpretation was given to the mechanism of IR fluorescence emission which is based on the energy transferring and up-conversion of Tm3+, Yb3+ and Er3+.
    Spectrochimica Acta Part A-molecular and Biomolecular Spectroscopy - SPECTROCHIM ACTA PT A-MOL BIO. 01/2009;
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    ABSTRACT: The inactivation of the A(2A) receptor (A(2A)R) has been shown to neuroprotect against brain injury in several animal models of neurological disorders including stroke and Parkinson's disease. However, despite marked elevation of adenosine level, the role of the A(2A) in traumatic brain injury (TBI) remains unclear. In the present study, we investigated the effects of genetic inactivation of A(2A)Rs in the acute stage. The A(2A)R knock-out (KO) mice and their wild-type (WT) littermates were subjected to cortical impact injury by a dropping weight. The control group was only craniotomized without TBI. At 24 h post-TBI, the neurological deficit scores of the KO mice were significantly lower than that of WT littermates. Consistent with the behavioral changes, the brain water contents as well as histological changes and the TUNEL-positive cells of the injured cortex of the KO mice were significantly lower than that of WT littermates. Furthermore, the glutamate level in the cerebral spinal fluid (CSF) of the KO mice was also significantly lower than that of WT littermates. In addition, we found that at 12 h post-TBI the mRNA and protein levels of TNF-alpha and IL-1beta were higher in the KO mice than that in the WT littermates. However, at 24 h post-TBI, the level of TNF-alpha and IL-1beta continually increased in the WT mice but largely declined in the KO mice. These results suggest that the genetic inactivation of A(2A)R protects against TBI, which is mainly associated with the suppression of glutamate level.
    Experimental Neurology 11/2008; 215(1):69-76. · 4.65 Impact Factor
  • Shuangshuang Dai, Hao Wang, Jianhong An, Nan Yang, Yuanguo Zhou
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    ABSTRACT: To establish a model of inactivation adenosine A2A receptors in brain tissues of mice, we transplanted bone marrow cells (BMCs) from wild type (WT) C57BL/6 mice into A2A receptor knockout (A2A KO) C57BL/6 mice which were previously fractionated total body irradiation of 6.2 Gyx2. Six weeks later, we identified and evaluated the model. The results showed that the sexual chromagene pattern on white blood cells of recipient mice changed from female pattern to male pattern and there were 95.9% of A2AR+ cells in peripheral white blood cells of recipient mice, whereas there was no significant difference of A2AR mRNA level in brains between these recipient mice and A2AR KO mice. Furthermore, there was no significant difference of breathing frequency, brain water content and level of glutamate between the model mice and WT mice. These results indicated that we established successfully a mouse model of inactivation adenosine A2A receptors in brain tissues. This may provide a new and efficient strategy to study the effect of adenosine A2A receptors in disease and injuries of central nervous system.
    Sheng wu gong cheng xue bao = Chinese journal of biotechnology 05/2008; 24(4):700-6.
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    ABSTRACT: Caffeine, the most consumed psychoactive drug and non-specific adenosine receptor antagonist, has recently been shown to exert a neuroprotective effect against brain injury in animal models of Parkinson’s disease (PD) and stroke. However, the effects of caffeine on traumatic brain injury (TBI) are not known. In this study, we investigated the effects of acute and chronic caffeine treatment on brain injury in a cortical-impact model of TBI in mice. Following TBI, neurological deficits, cerebral edema, as well as inflammatory cell infiltration were all significantly attenuated in mice pretreated chronically (for 3 weeks) with caffeine in drinking water compared with the mice pretreated with saline. Furthermore, we found that chronic caffeine treatment attenuated glutamate release and inflammatory cytokine production, effects that were correlated with an upregulation of brain A1 receptor mRNA. By contrast, acute treatment with caffeine (i.p. injection, 30 min before TBI) was not effective in protecting against TBI-induced brain injury. These results suggest that chronic (but not acute) caffeine treatment attenuates brain injury, possibly by A1 receptor-mediated suppression of glutamate release and inhibition of excessive inflammatory cytokine production. These results highlight the potential benefit of chronic caffeine intake for preventing TBI and provide a rationale for the epidemiological investigation of the potential association between TBI and human caffeine intake.
    Neuroscience 03/2008; · 3.12 Impact Factor
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    ABSTRACT: Up-conversion luminescence and energy transfer (ET) processes in Nd3+–Yb3+–Er3+ triply doped TeO2–ZnO–Na2O glasses have been studied under 800 nm excitation. Intense green up-conversion emissions around 549 nm, which can be attributed to the Er3+: 4S3/2→4I15/2 transition, are observed in triply doped samples. In contrast, the green emissions are hardly observed in Er3+ singly doped and Er3+–Yb3+ codoped samples under the same condition. Up-conversion luminescence intensity exhibits dependence of Yb2O3-concentration and Nd2O3-concentration. Up-conversion mechanism in the triply doped glasses under 800 nm pump is discussed by analyzing the ET among Nd3+, Yb3+ and Er3+. And a possible up-conversion mechanism based on sequential ET from Nd3+ to Er3+ through Yb3+ is proposed for green and red up-conversion emission processes.
    Journal of Luminescence 01/2007; 126:677-681. · 2.14 Impact Factor
  • T XU, X ZHANG, S DAI, Q NIE, X SHEN
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    ABSTRACT: Er/Yb co-doped (85-x)TeO2 15B2O3 xSiO2 (TBS x=0, 5, 10, 15, 20 mol%) glasses had been prepared. Effect of SiO2 content on the thermal stability and spectroscopic properties of Er/Yb co-doped tellurite borate glasses have been investigated. With SiO2 content increasing from 0 to 20 mol%, the T and T, the fluorescence full width at half maximum (FWHM), the peak of stimulated emission cross-section (σ), the measured lifetime (τ) and quantum efficiency (η) change from 398C, 530C, 75 nm, 5.7×10cm, 1.84 ms, 56.4% to 419C, 593C, 71 nm, 7.5×10cm, 2.38 ms, 70.6%, respectively. The results indicate that for Er/Yb co-doped tellurite borate glasses, introducing a suitable amount of SiO2 content is helpful for the improvement of thermal stability and the incremental of the lifetime of I13/24 level and quantum efficiency of Er:I13/24→I15/24 transition, while keeping the FWHM relatively large.
    Physica B Condensed Matter 01/2007; 389(2):242-247. · 1.33 Impact Factor
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    ABSTRACT: The lasing in an end-pumped gain guided index-antiguided (GG-IAG) Yb3+-doped silicate glass fiber with a 200μm diameter core is demonstrated. Laser beams with similar beam propagation factors M 2 and mode field diameters W 0 (>160μm) were observed at the output end of the GG-IAG fibers under different pump powers, which indicated that single mode behavior and excellent beam quality were achieved during propagation. Furthermore, the laser amplifier characteristics in the present Yb3+-doped GG-IAG fiber were also evaluated.
    Applied Physics B 98(2):301-304. · 1.78 Impact Factor