Search

SnO2 quantum dots (QDs) are potential materials for deep ultraviolet (DUV) light emitting devices. In this study, we report the temperature and excitation power-dependent exciton luminescence from SnO2 QDs. The exciton emission exhibits anomalous blue shift, accompanied with band width reduction with increasing temperature and excitation power above 300K. The anomalous temperature dependences of the peak energy and band width are well interpreted by the strongly localized carrier thermal hopping process and Gaussian shape of band tails states, respectively. The localized wells and band tails at conduction minimum are considered to be induced by the surface oxygen defects and local potential fluctuation in SnO2 QDs. [ABSTRACT FROM AUTHOR]

VO2 (M) thin films with good optical switching properties have been grown by reactive sputtering method. The influence of sputtering parameters on the structural and optical properties of the as-grown VO2 thin films was investigated, and the correlation between the microstructure and optical switching properties were studied. It was found that the phase transition temperature, hysteresis width, and the amplitude of the transition depend on the sputtering gas pressure, and the amplitude of the transition can reach as high as 70% with an approximately zero infrared transmission in metal state at a wavelength of 2.5 μm. The anomalous optical properties of the VO2 thin films were analyzed and discussed together with the studies of the refractive index and optical band gap. [ABSTRACT FROM AUTHOR]

OBJECTIVE: MicroRNAs (miRNAs) have great effects on the progression of cervical cancer (CC). This study aimed to investigate the role of miR-195-5p in CC and to explain the regulatory mechanism between ARL2 and miR-195-5p. PATIENTS AND METHODS: Quantitative Real-Time-Polymerase Chain Reaction (qRT-PCR) was used to detect miR-195-5p levels in CC tissues and cell lines. Transwell assays for cell migration and invasion were also performed. A luciferase reporter assay was used to detect the direct target of miR-195-5p. The protein levels of ARL2 were measured by Western blot analysis. RESULTS: In CC tissues and cell lines, miR-195-5p expression was decreased. Downregulation of miR-195-5p was associated with higher FIGO stage, deep stromal invasion, and lymph node metastasis. Moreover, over-expression of miR-195-5p inhibited cell migration and invasion in CC. Furthermore, it was observed that miR-195-5p directly targeted ARL2, which affected the suppressive effect of miR-195-5p in CC. CONCLUSIONS: MiR-195-5p inhibited cell migration and invasion in CC by suppressing ARL2 expression. The miR-195/ARL2 axis may provide a pathway for cell metastasis in CC. [ABSTRACT FROM AUTHOR]

OBJECTIVE: This study aims to uncover the biological functions of the feedback loop tripartite motif-containing 24 (TRIM24)/ Forkhead Box M1 (FOXM1) in the pathological progression of ovarian cancer (OC) and the underlying mechanism. PATIENTS AND METHODS: The expression levels of TRIM24 and FOXM1 in OC tissues and cells were determined by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). The potential correlation between TRIM24 level and clinical indexes of OC patients was analyzed. The Kaplan-Meier curves were depicted for evaluating the prognostic potentials of TRIM24 and FOXM1 in OC patients. The regulatory effects of TRIM24 and FOXM1 on proliferative, migratory, and invasive capacities of SKOV3 and OVCAR3 cells were assessed through functional experiments. The rescue experiments were performed to clarify the feedback loop TRIM24/FOXM1 in influencing the progression of OC. RESULTS: TRIM24 was upregulated in OC tissues and cells. The high level of TRIM24 was linked to higher rates of lymphatic and distant metastasis and worse survival in OC patients. The silence of TRIM24 attenuated proliferative, migratory, and invasive capacities of SKOV3 and OVCAR3 cells. FOXM1 level was negatively regulated by TRIM24, which was downregulated in OC. The low level of FOXM1 predicted worse survival in OC patients. Besides, the rescue experiments demonstrated that the feedback loop TRIM24/FOXM1 aggravated the malignant progression of OC. CONCLUSIONS: TRIM24 is upregulated in OC tissues, and closely linked to the occurrence of lymphatic and distant metastasis. Through negatively regulating FOXM1 level, TRIM24 aggravates the progression of OC. [ABSTRACT FROM AUTHOR]

The optical properties of nitrogen-doped SnO2 films with different N2/(N2+O2) gas ratios grown by reactive sputtering were studied by spectroscopy ellipsometry. The optical dielectric functions of the films were simulated by the Tauc-Lorentz model. It was found that the refractive index and extinction coefficient of nitrogen-doped SnO2 films increase and the band gap has a redshift with the increase of the N2 ratios. The general influences of the electronegativity and bond ionicity on the band gap, the refractive index in the spectral region below the fundamental absorption edge of nitrogen-doped SnO2, and other doped semiconductors are demonstrated. [ABSTRACT FROM AUTHOR]

The microstructure and optical properties of MgO–TiO2 composite thin films prepared by radio frequency magnetron sputtering were studied. The composite films have an amorphous structure and the growth rate of the composite film increases with increasing Mg content. The refractive index almost linearly decreases with increasing Mg content in the composite films at wavelength larger than 300 nm and can be adjusted in the wide range between the refractive index of TiO2 and that of MgO. The extinction coefficient decreases with Mg content and is nearly zero at visible light region. The optical band gap of the composite films determined from the absorption spectra increases with Mg content, and has a good agreement with that obtained from spectroscopic ellipsometry simulation. A broad photoluminescence band in the visible region was observed in the composite films with high Mg content and was considered resulted from the oxygen vacancies. [ABSTRACT FROM AUTHOR]

The influence of annealing on the morphological, structural, and optical properties of ZnO:Tb thin films on Si substrate grown by magnetron cosputtering is investigated. It has been found that the ZnO:Tb thin films with structures of tetrapod and screwlike nanorod are formed after annealing at temperature of 950 °C. X-ray photoelectron spectroscopy, energy dispersive spectroscopy, and Raman analyses prove that the tetrapod-aiguille zinc oxide (T-A-ZnO) and the screwlike nanorods are composed of Zn, Tb, and O elements. The photoluminescence spectra of the ZnO:Tb thin films with the T-A-ZnO structure and the screwlike nanorods are featured with two ultraviolet emission peaks and one strong green emission band, and the photoluminescence intensity increases with increasing annealing temperature. The surface defects in the T-A-ZnO structure and the screwlike nanorods are considered to be responsible for enhanced green emission in the annealed ZnO:Tb thin films. [ABSTRACT FROM AUTHOR]

A correction to article "MiR-195-5p inhibits the cell migration and invasion of cervical carcinoma through suppressing ARL2" published in a previous issue of the periodical is presented.

An enhanced mid-infrared absorption in Ag nanoparticles-decorated TiO2 microflowers was reported. It was found that the mid-infrared absorption of the Ag/TiO2 complex depends strongly on the content and size of Ag nanoparticles, the higher the Ag nanoparticles content, the stronger the infrared absorption. The average reflectivity in the entire mid-infrared region of the microflowers drops from 57.6% to 10.5% after Ag nanoparticles decoration. Reversible modulated midinfrared absorption properties were found in the Ag/TiO2 complexes upon alternative illumination of visible and UV light due to the photoinduced interfacial electron transfer between TiO2 semiconductor and Ag nanoparticles. [ABSTRACT FROM AUTHOR]

Nanocrystalline compound thin films of ZnO-TiO2 with different Zn/Ti atomic ratios were prepared by radio frequency magnetron reactive sputtering. The optical constants and the optical band gap were investigated using spectroscopic ellipsometry and the optical absorption spectrum. It was found that the cubic ZnTiO3 phase can be obtained with the atomic ratio of Zn to Ti of about 1:1, and transforms to rhombohedral ZnTiO3 phase and a phase mixture of rhombohedral ZnTiO3 and ZnO with increasing Zn content. The refractive index decreases with the increase of Zn content, and the extinction coefficient in the visible range is near zero. The optical band gap was derived from the modeling of ellipsometry data and extinction coefficient spectra, and compared with that obtained from optical absorption spectrum, and it was found that the optical band gaps obtained by these three methods are consistent with each other. [ABSTRACT FROM AUTHOR]

Nitrogen-incorporated SnO2 thin films have been grown on Si(100) and quartz substrates by reactive sputtering of a Sn target in gas mixtures of N2–O2. The structure of the nitrogen-incorporated SnO2 thin films was studied by X-ray diffraction, and the changes in the chemical bonds and atomic binding states of the nitrogen-incorporated SnO2 thin films were analyzed by X-ray photoelectron spectroscopy. It was found that the binding energy of Sn 3d and O 1s shifts 0.65 eV and 0.35 eV, respectively, toward the lower-energy side after nitrogen was incorporated into the SnO2 thin films as a comparison with that of pure SnO2 film. The indirect optical band gap gradually decreases from 3.42 eV to 3.23 eV, i.e. from the UV to the edge of the visible-light range, with increasing nitrogen flux content in the N2–O2 gas mixtures. [ABSTRACT FROM AUTHOR]

We study the optical properties of amorphous GaAs1-xNx films grown by radio frequency magnetron sputtering method with different N2 partial pressures. The surface morphology, the optical absorption, the Raman spectra, and optical constants of the films with different N2 partial pressures are reported. The appearance of the Raman peak at 245 cm-1 of “GaAslike” and a shoulder at about 750 cm-1 related to GaN indicates the formation of GaN clusters in GaAs matrix. The roughness decreases and the optical band gap of amorphous GaAs1-xNx films moves to short wavelength with increasing N2 partial pressure. The refractive index and the extinction coefficient of the films decrease with increasing N2 partial pressure, and it has been found that the amorphous GaAs1-xNx films with nonzero N2 partial pressure are transparent in red and near infrared wavelength regions. [ABSTRACT FROM AUTHOR]