| 1. |
- Gao, Feng, et al.
(författare)
-
Effects of substrate temperature on Bi0.8La0.2FeO3 thin films prepared by pulsed laser deposition
- 2007
-
Ingår i: Thin Solid Films. - : Elsevier. - 0040-6090 .- 1879-2731. ; 515:13, s. 5366-5373
-
Tidskriftsartikel (refereegranskat)abstract
- Bi0.8La0.2FeO3 thin films on Pt/TiO2/SiO2/Si substrates at various substrate temperatures from 500 degrees C to 750 degrees C are prepared by pulsed laser deposition, and their microstructures and ferroelectric/magnetic properties are carefully investigated using various techniques. It is observed that the crystallographic orientation and Fe-ion valence state depend significantly on the substrate temperature, which consequently influences considerably on the ferroelectric and magnetic properties of the thin films. A considerable improvement of the ferroelectric and magnetic properties of the thin films can be achieved by optimizing the substrate temperature for deposition. (C) 2007 Elsevier B.V. All rights reserved.
|
|
| 2. |
- Chen, K., et al.
(författare)
-
High permittivity in zr doped NiO ceramics
- 2007
-
Ingår i: Journal of Applied Physics. - : American Institute of Physics (AIP). - 0021-8979 .- 1089-7550. ; 102:3, s. 034103-
-
Tidskriftsartikel (refereegranskat)abstract
- We report on measurements of the dielectric permittivity of NiO-based ceramics doped with Zr (ZNO). Samples were prepared by the traditional solid-state reaction method. The concentration of Zr has an effect on the dielectric properties of ZNO ceramics. High permittivity values (similar to 10(4)) were observed which remain almost constant from 200 K to 350 K at low frequencies. The high-dielectric-constant response of the ZNO ceramics is attributed mainly to a grain boundary (internal) barrier layer capacitance. (c) 2007 American Institute of Physics.
|
|
| 3. |
- Fu, Qiang, et al.
(författare)
-
Exploring at nanoscale from first principles
- 2009
-
Ingår i: FRONTIERS OF PHYSICS IN CHINA. - : Springer Science and Business Media LLC. - 1673-3487 .- 1673-3606. ; 4:3, s. 256-268
-
Tidskriftsartikel (refereegranskat)abstract
- Systems at the nanoscale can exhibit distinctive and unexpected properties in electrical, magnetic, mechanical, and chemical aspects. Understanding these properties not only is of importance from the fundamental scientific view but also offers great opportunities for future applications. Theoretical calculations can provide important information to interpret, modify, and predict the novel properties of objects at the nanoscale and therefore play a significant role in the process of exploring the nano world. In this review, six different areas are briefly presented, namely, prediction of new stable structures, modi. cation of properties (especially the electronic structures), design of novel devices for applications, the structures and catalytic effects of clusters, the mechanical and transport properties of gold nanowires, and improvement of materials for hydrogen storage. Based on these examples, we show what can be done and what can be found in the investigations of nanoscale systems with participation of theoretical calculations.
|
|
| 4. |
- Gao, Feng, et al.
(författare)
-
Preparation and photoabsorption characterization of BiFeO3 nanowires
- 2006
-
Ingår i: Applied Physics Letters. - : American Institute of Physics (AIP). - 0003-6951 .- 1077-3118. ; 89:10, s. 102506-
-
Tidskriftsartikel (refereegranskat)abstract
- Perovskite-type polycrystalline BiFeO3 (BFO) nanowires (similar to 50 nm in diameter and similar to 5 mu m in length) were synthesized using the anodized alumina template technique. An energy band gap of similar to 2.5 eV was determined from the UV-visible diffuse reflectance spectrum, and its photocatalytic ability to produce O-2 was revealed under UV irradiation. Weak ferromagnetism at room temperature and superparamagnetism at low temperature were observed for the BFO nanowires, different from the antiferromagnetic order in bulk BFO, reflecting the significant size effects on the magnetic ordering of BFO. (c) 2006 American Institute of Physics.
|
|
| 5. |
- Gao, Feng, et al.
(författare)
-
Preparation of la-doped BiFeO3 thin films with Fe2+ ions on Si substrates
- 2006
-
Ingår i: Journal of Applied Physics. - : American Institute of Physics (AIP). - 0021-8979 .- 1089-7550. ; 99:9, s. 094105-
-
Tidskriftsartikel (refereegranskat)abstract
- La-doped BiFeO3 thin films with Fe2+ ions have been prepared on Pt/TiO2/SiO2/Si substrates by pulsed laser deposition in order to enhance the ferroelectric and magnetic properties. The targets for the film deposition were synthesized using a rapid liquid phase sintering technique to ensure the low leakage. The dielectric properties at room temperature and above were investigated. It was observed that the La doping greatly enhances the ferroelectric polarization at room temperature by modifying the film structure from rhombohedral to monoclinic. The saturation magnetization was enhanced about two times due to the Fe2+ ions in the thin films. (C) 2006 American Institute of Physics.
|
|
| 6. |
- Gao, Feng, et al.
(författare)
-
Visible-light photocatalytic properties of weak magnetic BiFeO3 nanoparticles
- 2007
-
Ingår i: Advanced Materials. - : Wiley-VCH Verlag. - 0935-9648 .- 1521-4095. ; 19:19, s. 2889-2892
-
Tidskriftsartikel (refereegranskat)abstract
- Polycrystalline BiFeO3 nanoparticles (size 80-120 nm) are prepared by a simple sol-gel technique. Such nanoparticles are very efficient for photocatalytic decomposition of organic contaminants under irradiation from ultraviolet to visible frequencies. The BiFeO3 nanoparticles also demonstrate weak ferromagnetism of about 0.06 mu(B)/Fe at room temperature, in good agreement with theoretical calculations.
|
|
| 7. |
- Hua, Dong, et al.
(författare)
-
Small interfering RNA-directed targeting of toll-like receptor 4 inhibits human prostate cancer cell invasion, survival, and tumorigenicity
- 2009
-
Ingår i: Molecular Immunology. - : Elsevier BV. - 0161-5890 .- 1872-9142. ; 46:15, s. 2876-2884
-
Tidskriftsartikel (refereegranskat)abstract
- A major cause of tumor treatment failure is cancer cell metastasis. Toll-like receptor 4 (TLR4)-mediated signaling has been implicated in tumor cell invasion, survival, and metastasis in a variety of cancers. In this study, we investigated the biological roles of TLR4 in prostate metastatic cell invasion and survival, and the potential of gene silencing of TLR4 using small interfering RNA (siRNA) for treatment of cancer. In cultured human prostate cancer cell lines, TLR4 were higher PC3 and DU145 as compared with the poorly metastatic LNCaP indicating that up-regulation of TLR4 was positively correlated with metastasis of tumor cell. In the highly metastatic cancer cell PC3, gene silencing of TLR4 using siRNA significantly inhibited TLR4 mRNA expression and protein level. Knockdown of TLR4 in PC3 cells resulted in a dramatic reduction of tumor cell migration and invasion as indicated by a Matrigel invasion assay. Furthermore, TLR4 siRNA suppressed cell viability and ultimately caused the induction of apoptotic cell death. The effects were associated with abrogating TLR4-mediated signaling to downstream target molecules such as myeloid differentiation factor 88 (MyD88), adaptor-inducing IFN-beta (TRIF), and interferon regulatory factor-1 (IRF-1). In a mouse prostate cancer model, administration with the plasmid construct expressing siRNA for TLR4 obviously inhibited established tumor growth and survival. These studies revealed evidence of a multifaceted signaling network operating downstream of TLR4-mediated tumor cell invasion, proliferation, and survival. Thus, RNA interference-directed targeting of TLR4 may raise the potential of its application for cancer therapy.
|
|
| 8. |
- Lin, Yuan-Hua, et al.
(författare)
-
Electrical transport properties of La2CuO4 ceramics processed by the spark plasma sintering
- 2007
-
Ingår i: Journal of The American Ceramic Society. - : Wiley. - 0002-7820 .- 1551-2916. ; 90:12, s. 4005-4008
-
Tidskriftsartikel (refereegranskat)abstract
- Highly dense La2CuO4 ceramics have been prepared by the spark plasma sintering technique. Temperature dependence of electrical conductivity indicates that La2CuO4 ceramics sintered at over 875 degrees C exhibit a metal-like behavior, which should be ascribed to the special La2CuO4 crystal structure and its correlation splitting of the half-filled d(x2-y2) band. Our experimental data indicate that all of the La2CuO4 samples exhibit positive thermoelectric power in the whole measuring temperature range, indicating that the majority of charge carriers are holes. It is desirable to obtain good thermoelectric performance for this system by optimizing the electrical properties and reducing the thermal conductivity.
|
|
| 9. |
- Liu, J. -M., et al.
(författare)
-
Ferroelectric and magnetoelectric behaviors of multiferroic BiFeO3 and piezoelectric-magnetostrictive composites
- 2008
-
Ingår i: Journal of Electroceramics. - : Springer Verlag (Germany). - 1385-3449 .- 1573-8663. ; 21:1-4, s. 78-84
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper we overview our recent work on ferroelectric and magnetoelectric coupling behaviors of multiferroic doped BiFeO3 (BFO) and piezoelectric-magnetostrictive composites. Using rapid liquid sintering method we prepare single-phase BFO ceramics of excellent ferroelectric property. The BFO thin films on Pt-coated silicon wafers by pulsed laser deposition show large remnant polarization but serious ferroelectric switching fatigue. A series of piezoelectric-magnetostrictive composite structures in bulk and thin film forms are prepared and giant magnetoelectric coupling effect of them is observed. The experimentally measured results are confirmed by numerical modeling based on piezoelectric and magnetostrictive constitution equations.
|
|
| 10. |
- Meng, Wen-Jian, et al.
(författare)
-
Microsatellite instability did not predict individual survival in sporadic stage II and III rectal cancer patients
- 2007
-
Ingår i: Oncology. - : S. Karger AG. - 0890-9091 .- 0030-2414 .- 1423-0232. ; 72:1-2, s. 82-88
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives: Tumors with high-frequency microsatellite instability (MSI-H) have unique biological behavior and the predictive role of microsatellite instability (MSI) status on survival of colorectal cancer is still debated. The prognostic significance of MSI status in sporadic stage II and III rectal cancer patients needs to be more precisely defined. So we investigated the relationship between MSI status and clinicopathological features and prognosis in these patients. Methods: DNAs from fresh-frozen paired samples of tumors and corresponding normal tissue from 128 stage II and III rectal cancer patients were analyzed for MSI by PCR amplification using markers recommended by a National Cancer Institute workshop on MSI. To assess prognostic significance, Cox proportional hazards modeling was used. Results: Twelve (9.3%) tumors in our study were MSI-H, 28 (21.9%) were low-frequency MSI (MSI-L) and 88 (68.8%) were microsatellite stable (MSS). Most of the MSI-H tumors compared with MSI-L and MSS tumors were found in female patients (p = 0.031), had mucinous histology (p = 0.023), high grade of differentiation (p = 0.002) and high level of preoperative serum carcinoembryonic antigen (p = 0.005). Rectal cancer patients with MSI-H did not show a better clinical outcome than those with MSI-L/MSS, neither in all cases (p = 0.986) nor in stage II and stage III disease analyzed separately (p = 0.705 and p = 0.664, respectively). Conclusions: Data provided here demonstrated there was high incidence of MSI-H and MSI was not a prognostic factor in sporadic stage II and III rectal cancers from the Chinese Han population included in this study. Tumor stage is more suitable than MSI status for prediction of individual survival in sporadic stage II and III rectal cancer patients. Copyright © 2007 S. Karger AG.
|
|
