Electrical Measurements of an AlGaN/GaN High-electron-mobility Transistor Structure Grown on Si

Zhi-Yao Zhang,Shun-Tsung Lo,Li-Hung Lin,Kuang Yao Chen,J. Z. Huang,Zhi-Hao Sun,C.-T. Liang,N. C. Chen,Chin-An Chang,P. H. Chang 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.61 No.9

We report on magnetotransport results for an Al_0.15Ga_0.85N/GaN high-electron-mobility-transistor structure grown on a p-type Si (111) substrate. Our results show that there exists an approximately temperature (<i>T</i>)-independent point, which could be ascribed to a direct transition from a weak insulator to a high Landau level filling factor quantum Hall state, exists in the longitudinal resistivity ρ_xx. The Hall resistivity decreases with increasing <i>T</i>, compelling experimental evidence for electron-electron interaction effects in a weakly-disordered two-dimensional (2D) system. We find that electron-electron interaction effects can be estimated and eliminated, giving rise to a corrected nominally temperature-independent Hall slope. By fitting the low-field magnetotransport data to conventional 2D weak localization theory, we find that the dephasing rate 1/τ_φ is proportional to <i>T</i>. Moreover, 1/τ_φ is finite as <i>T</i> → 0, evidence for zero-temperature dephasing in our system.

Scutellaria Extract Decreases the Proportion of Side Population Cells in a Myeloma Cell Line by Down-regulating the Expression of ABCG2 Protein

Lin, Mei-Gui,Liu, Li-Ping,Li, Chen-Yin,Zhang, Meng,Chen, Yuling,Qin, Jian,Gu, Yue-Yu,Li, Zhi,Wu, Xin-Lin,Mo, Sui-Lin Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.12

Background and Aims: Scutellaria is one of the most popular traditional Chinese herbal remedies against various human diseases, including cancer. In this study, we examined the active effects of Scutellaria extract and its main flavonoid constituents on the proportion of side population cells within human multiple myeloma cell line RPMI8226 in vitro and explored the potential molecular mechanisms involved. Materials and Methods: The contents of flavonoids in ethanolic extract of Scutellaria baicalensis Georgi were determined using high performance liquid chromatography. The antiproliferative effect of the ethanolic extract on RPMI-8226 was determined by CCK assay. Apoptosis was measured by annexin combining with propidium iodide in a flow cytometer. Cell cycle analysis was performed by propidium iodide staining in combination with flow cytometry analysis. Hoechst 33342 exclusion assay was used for the identification of side population within RPMI8226 cells. The expression of ABCG2 protein was assessed by Western blotting assay. Results: The content of major flavonoids constitutents of Scutellaria extract was baicalin (10.2%), wogonoside (2.50%), baicalein (2.29%), and wogonin (0.99%), respectively. The crude Scutellaria extract did not show significant anti-proliferative effect, apoptosis induction and cell cycle arrest in RPMI-8226 within the concentrations of $1-75{\mu}g/mL$. However, the ethanolic extract, baicalein, wogonin and baicalin reduced the side population cells in RPMI-8226, and data showed that baicalein and wogonin had stronger inhibitory effects. Correspondingly, they also exhibited significant effects on decreasing the expression level of ABCG2 protein in RPMI-8226 in vitro. Conclusions: Our results for the first time demonstrated a novel mechanism of action for Scutellaria extract and its main active flavonoids, namely targeting SP cells by modulating the expression of ABCG2 protein. This study provides an insight for new therapeutic strategies targeting cancer stem cells of multiple myeloma.

VUV spectroscopic properties of rare-earth (RE³⁺ = Sm³⁺, Eu³⁺, Tb³⁺, Dy³⁺) -activated layered borate Ba₆Gd₉B₇₉O₁₃₈

Zhang, Zhi-Jun,Zhang, Shao-Lin,Zhang, Wei-Bin,Yang, Woochul Elsevier 2017 SOLID STATE SCIENCES Vol.64 No.-

<P><B>Abstract</B></P> <P>Vacuum ultraviolet (VUV) spectroscopic properties of rare-earth RE<SUP>3+</SUP>- activated (RE<SUP>3+</SUP> = Sm<SUP>3+</SUP>, Eu<SUP>3+</SUP>, Tb<SUP>3+</SUP> and Dy<SUP>3+</SUP>) Ba<SUB>6</SUB>Gd<SUB>9</SUB>B<SUB>79</SUB>O<SUB>138</SUB> borates (BGBO) are investigated. The strong absorption bands in the VUV range of un-doped and RE<SUP>3+</SUP>-activated BGBO were observed. The band range from 140 to 200 nm with a peak at about 173 nm results from the host lattice absorption. For Sm<SUP>3+</SUP>-activated BGBO, the charge transfer transition from O<SUP>2-</SUP> to Sm<SUP>3+</SUP> was observed at 202 nm. In addition, it exhibits bright red emission originating from the Sm<SUP>3+</SUP> <I>f</I>-<I>f</I> transitions of <SUP>4</SUP>G<SUB>5/2</SUB> → <SUP>6</SUP>H<SUB> <I>J</I> </SUB> (<I>J</I> = 5/2, 7/2 and 9/2). The O<SUP>2-</SUP>-Eu<SUP>3+</SUP> charge transfer (CT) at 249 nm is observed in the excitation spectrum for Eu<SUP>3+</SUP>-doped BGBO. For Tb<SUP>3+</SUP>-activated BGBO, the broad bands around 208 and 230 nm are due to the spin-allowed and spin-forbidden <I>f</I>-<I>d</I> transitions of Tb<SUP>3+</SUP>, respectively. In addition, the absence of the <I>f</I>-<I>d</I> transitions of Sm<SUP>3+</SUP> and Dy<SUP>3+</SUP> in the excitation spectra probably due to the photo-ionization effect. It is demonstrated that there are energy transfers from the BGBO host lattice to the luminescent activators depending on the activators.</P> <P><B>High lights</B></P> <P> <UL> <LI> VUV spectroscopic properties of rare-earth ions in Ba<SUB>6</SUB>Gd<SUB>9</SUB>B<SUB>79</SUB>O<SUB>138</SUB> have been investigated. </LI> <LI> The CT bands of O<SUP>2-</SUP>-Sm<SUP>3+</SUP> and O<SUP>2-</SUP>-Eu<SUP>3+</SUP> charge transfer bands were observed at 202 and 249 nm, respectively. </LI> <LI> The <I>f</I>-<I>d</I> spin-allowed (208 nm) and spin-forbidden (230 nm) transitions of Tb<SUP>3+</SUP> were observed. </LI> <LI> Energy transfer from the host to rare-earth activators has been demonstrated. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Overexpression of NDRG2 Can Inhibit Neuroblastoma Cell Proliferation through Negative Regulation by CYR61

Zhang, Zhi-Guo,Li, Gang,Feng, Da-Yun,Zhang, Jian,Zhang, Jing,Qin, Huai-Zhou,Ma, Lian-Ting,Gao, Guo-Dong,Wu, Lin Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.1

Several recent studies have showed that the n-myc downstream regulated gene 2 (NDRG2) is a new tumor suppressor gene, and that it plays an important role in tumor suppression in several cancers or cancer cell lines. However, few studies focused on its function in neuroblastoma cells. In the present investigation, we demonstrated that NDRG2 overexpression inhibited their proliferation. Using a cDNA microarray, we found that overexpression of NDRG2 inhibited the expression of cysteine-rich protein 61 (CYR61), a proliferation related gene. From our research, CYR61 may partially hinder NDRG2-mediated inhibition of cell proliferation. Overexpression of NDRG2 resulted in accumulation of cells in the G1 phase, which was accompanied by upregulation of p21 and p27 and downregulation of CDK4 and cyclin D1. Taken together, these data indicate that NDRG2 inhibits the proliferation of neuroblastoma cells partially through suppression of CYR61. Our findings offer novel insights into the physiological roles of NDRG2 in neuroblastoma cell proliferation, and NDRG2 may prove to be effective candidate for the treatment of children with neuroblastoma.

Distinctive Endophytic Fungal Assemblage in Stems of Wild Rice (Oryza granulata) in China with Special Reference to Two Species of Muscodor (Xylariaceae)

Zhi-lin Yuan,Zhen-zhu Su,Li-juan Mao,Yang-qing Peng,Guan-mei Yang,Fu-cheng Lin,Chu-long Zhang 한국미생물학회 2011 The journal of microbiology Vol.49 No.1

Ecological niches in the rhizosphere and phyllosphere of grasses capable of sustaining endophytes have been extensively studied. In contrast, little information regarding the identity and functions of endophytic fungi in stems is available. In this study, we investigated the taxonomic affinities, diversity, and host specificities of culturable endophytes in stems of wild rice (Oryza granulata) in China. Seventy-four isolates were recovered. Low recovery rate (11.7%) indicated that there were relatively few sites for fungal infection. Identification using morphology, morphospecies sorting, and molecular techniques resulted in classification into 50 taxa, 36 of which were recovered only once. Nucleotide sequence similarity analysis indicated that 30% of the total taxa recovered were highly divergent from known species and thus may represent lineages new to science. Most of the taxa were classified as members of the classes Sordariomycetes or Dothideomycetes (mainly in Pleosporales). The presence of Arthrinium and Magnaporthaceae species, most often associated with poaceous plants, suggested a degree of host specificity. A polyphasic approach was employed to identify two Muscodor taxa based on (i) ITS and RPB2 phylogenies, (ii) volatile compounds produced, and (iii)an in vitro bioassay of antifungal activity. This to our knowledge is only the second report regarding the isolation of Muscodor spp. in China. Therefore, we hypothesize that wild plants represent a huge reservoir of unknown fungi. The prevalence, novelty, and species-specificity of unique isolates necessitate a reevaluation of their contribution to ecosystem function and fungal biodiversity.

A high performance of BPhen-based white organic light-emitting devices with a dual-emitting layer and its electroluminescent spectral property

Hua-Ping Lin,Fan Zhou,Jun Li,Xiao-Wen Zhang,Dong-Bin Yu,Liang Zhang,Xue-Yin Jiang,Zhi-Lin Zhang 한국공업화학회 2011 Journal of Industrial and Engineering Chemistry Vol.17 No.4

This work demonstrated the fabrication of white organic light-emitting devices (WOLEDs) using a dual emitting layer (d-EML) consisting of blue and ‘white’ emitters. In this d-EML system, the blue emitter not only emits but also assists the incomplete energy transfer. More importantly, it behaves as an effective trapping site for holes, which contributes to the efficient recombination of electron–hole pairs. The d-EML was constructed between the hole-transmitting layer (HTL) and the electron-transmitting layer (ETL) of Alq3 and BPhen. The thickness of the blue emitter used in the d-EML devices has an important effect on chromaticity and efficiency. Through the optimization of device structure, the reasonable white emission with Commission Internationale de L’Eclairage (CIE) color coordinates of (0.33, 0.33) and little color shift was obtained. The device showed an applicable luminance with its maximum luminance of 22,874 cd/m2 at a driving voltage of 16 V. The maximum luminance efficiency was achieved 8.10 cd/A,and the maximum power efficiency was reached 5.07 Lm/W. The result is explained with the help of the excitons generation and diffusion theory. According to the theory of excitons generation and diffusion,an equation has been set up which concerns electroluminescent spectra to the thickness of the two emitters and to the exciton diffusion length.

Elucidations of weak microcavity effect and improved pixel contrast ratio in Si-based top-emitting organic light-emitting diode

Xiao-Wen Zhang,Hua-Ping Lin,Jun Li,Fan Zhou,Bin Wei,Xue-Yin Jiang,Zhi-Lin Zhang 한국물리학회 2012 Current Applied Physics Vol.12 No.5

Microcavity effect and pixel contrast ratio (PCR) are key issues for top-emitting organic light-emitting diode (TOLED). Si and Ag are two widely used reflective anodes for constructing effective TOLEDs. The mechanism contributing to microcavity effect and PCR has been clarified by using conventional optoelectronic theory. Consequently, the differences of microcavity effect and PCR between Si-based and Agbased TOLEDs are discovered. Our results indicate that the Si-based TOLED possesses weak microcavity effect and improved PCR in comparison with Ag-based device. This is resulted from the low reflectivity and less reflective phase change of Si. The weak microcavity effect in Si-based TOLED also contributes to negligible variation of electroluminescent spectra with viewing angles and low device efficiency. Furthermore, Si-based TOLED shows rather high PCR which is about quintuple that of Ag-based device. Microcavity effect and pixel contrast ratio (PCR) are key issues for top-emitting organic light-emitting diode (TOLED). Si and Ag are two widely used reflective anodes for constructing effective TOLEDs. The mechanism contributing to microcavity effect and PCR has been clarified by using conventional optoelectronic theory. Consequently, the differences of microcavity effect and PCR between Si-based and Agbased TOLEDs are discovered. Our results indicate that the Si-based TOLED possesses weak microcavity effect and improved PCR in comparison with Ag-based device. This is resulted from the low reflectivity and less reflective phase change of Si. The weak microcavity effect in Si-based TOLED also contributes to negligible variation of electroluminescent spectra with viewing angles and low device efficiency. Furthermore, Si-based TOLED shows rather high PCR which is about quintuple that of Ag-based device.

Historical Long-term Exposure to Pentachlorophenol Causing Risk of Cancer - A Community Study

Zheng, Rui-Zhi,Zhang, Qing-He,He, Yi-Xin,Zhang, Qian,Yang, Lin-Shen,Zhang, Zhi-Hua,Zhang, Xiu-Jun,Hu, Jing-Ting,Huang, Fen Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.2

Background: Pervious studies suggested occupational workers exposure to pentachlorophenol (PCP) might contribute to increased risk of cancer. However, few studies have focused on associations between PCP and cancer risk at the community level. Objective: The present study was to explore the cancer risk for the community population living long-term in a PCP contaminated area. Methods: All the cancer cases diagnosed in 2009-2011 in Tongling City were collected. The cancer patients' residencies were geo-referenced in each district. The historical PCP usage for each district of Tongling was calculated as the PCP pollution index, which was further used to divide into PCP exposure categories. Standardized rate ratios (SRRs) of cancer incidence were applied to detect the cancer risk as exposure grade elevated. Correlation analysis was performed to analyze the relationship between PCP pollution and cancer incidence. Results: A total of 5,288 cancer cases (3,451 male and 1,837 female) were identified. PCP usage was correlated with the incidence of leukemia (r=0.88, P=0.002) for males, and with cancer of the esophagus for males (r=0.83, P=0.008) and females (r=0.71, P=0.020). Compared with the low exposure category, significant SRRs for total cancer sites was obtained for high PCP exposure category (SRR=1.61, 95%CI=1.59-1.62). Most SRR values of the cancer sites were significantly increased as exposure grade elevated and exposure time extended. Conclusion: The present study found that community residents living in the PCP contaminated area had increased risk of cancers. Leukemias, lymphomas and nasopharyngeal and esophageal cancers are most possibly associated with PCP exposure.

Efficient hole injection in blue organic light-emitting devices by using a double hole injection layer to improve chromaticity and electrical characteristics

Hua-Ping Lin,Fan Zhou,Xiao-Wen Zhang,Dong-Bin Yu,Jun Li,Liang Zhang,Xue-Yin Jiang,Zhi-Lin Zhang 한국물리학회 2011 Current Applied Physics Vol.11 No.3

A double hole injection layer consisting of Ag_2O//MoO_x was applied to a 4,40-bis (2,2-diphenylvinyl)-1,10-biphenyl-based blue organic light-emitting device (OLED). The hole current injection of the devicewas improved and the performance of the blue OLED was enhanced. We have observed that the insertion of such double layer leads to a striking improvement in chromaticity and electrical characteristics. This device showed much better chromaticity and less current-induced color shift as compared to the corresponding single hole injection layer counterparts. Using this strategy, a striking improvement in the electrical properties with lower driving voltage, higher power efficiency and a weak current-induced fluorescence quenching was achieved. This could be explained by the fact that an interlayer of Ag_2O//MoO_x provided a stepped energy level which greatly facilitated hole injection and hence enhanced injection current. The result is verified by using the J―V curves of ‘only’ devices and further explained with the help of Fowler-Nordheim (F-N) tunneling theory.

Study on molten salt oxidation process of simulated Co doped cation exchange resins

Yun Xue,Yue-Lin Wang,Yu Li,Wen-Da Xu,Fu-Qiu Ma,Yang-Hai Zheng,Qing-Guo Zhang,Zhi Zhang,Mi-lin Zhang,Yong-De Yan 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.126 No.-

Cation exchange resins (CERs) are widely applied to purify waste liquids generated during the operationof nuclear reactors. The radioactive nuclides 60Co and 58Co are important corrosion activation products inreactor cooling water. In this study, the simulated Co doped CERs were oxidized with ternary carbonate. According to the thermogravimetric analysis (TG), the decomposition of Co doped CERs includes threeprocesses: 1. Elimination of the osmotic water; 2. Pyrolysis of sulfonic acid group; 3. Destruction of styrene–divinylbenzene copolymer. The X-Ray Diffraction (XRD) patterns indicate that sulfur mainly exists inthe form of sulfate in waste salt. The Co2+ undergoes the path of CoS2 ? Co3O4 with the increase of temperatureand the transition point is 650 C. Combined with Fourier Transform Infrared Spectrometer (FTIR)spectra and X-ray Photoelectron Spectroscopy (XPS) analysis, sulfonic acid groups begin to decomposeat 350 C. During the molten salt oxidation process, most of the sulfur in sulfonic acid groups is entrappedby carbonate as the form of sulfate, and a little of which remains as sulfone group, sulfoxide group andsulfur bridge in residue. When the resins are oxidized at 800 C, the retention rate of Co2+ is 97.3%, indicatingthat the molten salt oxidation can effectively remain Co2+ and convert it into a more stablesubstance.