- [Show abstract] [Hide abstract] ABSTRACT: Although there are many reports about the efficacy of siRNAs, it is not clear whether those siRNAs with high C/G contents can be used to silence their target mRNAs efficiently. In this study, we investigated the structure and function of a group of siRNAs with high C/G contents. The results showed that single siRNAs against the Calpain, Otoferlin and Her2 mRNAs could induce different silencing effects on their targets, suggesting that the accessibility to target sequences influences the efficacy of siRNA. Unexpectedly, a single siRNA could target its cognate sequence in the 3'UTR of EEF1D or the 5'UTR of hTRF2 or CDC6. Their interaction induced different modes of gene silencing. Furthermore, the introduction of mutations into the 3' end of the passenger strand showed that the position and number of mutated nucleotides could exert some influence on the efficacy of siRNA. However, these mutations did not completely block the passenger strand from exerting its RNAi effect. Interestingly, our findings also indicated that the target mRNA might play essential roles in maintaining or discarding the guide strand in RISCs. Thus, the conclusion could be drawn that favorable siRNA sequences, accessible target structures and the fast cleavage mode are necessary and sufficient prerequisites for efficient RNAi.
- [Show abstract] [Hide abstract] ABSTRACT: Ramsdellite Li2Ti3O7 was first synthesized via sol–gel process with good crystallity of an average particle size of 0.175μm. The product was thoroughly investigated as a lithium intercalation compound, and as an active anode material in asymmetric supercapacitors coupling with activated carbon as cathode. Lithium intercalation reactions were found occurring at 1.32 and 1.62V versus Li/Li+, respectively. A reversible specific capacity of 150mAhg−1 at 1C was obtained on Li2Ti3O7 electrode in a nonaqueous electrolyte. The charge current was found to strongly influence the anodic discharge capacity in the asymmetric cell. The capacity retention at 10C charge–discharge rate was found to be 75.9% in comparison with that at 1C.
- [Show abstract] [Hide abstract] ABSTRACT: A large class of non-coding RNAs found in small molecule RNAs are closely associated with the regulation of gene expression, which are called microRNA (miRNA). MiRNAs are coded in intergenic or intronic regions and can be formed into foldback hairpin RNAs. These transcripts are cleaved by Dicer, generating mature miRNAs that can silence their target genes in different modes of action. Now, research on small molecule RNAs has gotten breakthrough advance in biology. To discover miRNA genes and their target genes has become hot topics in RNA research. This review attempts to look back the history of miRNA discovery, to introduce the methods of screening miRNAs, to localize miRNA loci in genome, to seek miRNA target genes and the biological function, and to discuss the working mechanisms of miRNAs. Finally, we will discuss the potential important roles of miRNAs in modulating the genesis, development, growth, and differentiation of organisms. Thus, it can be predicted that a complete understanding of miRNA functions will bring us some new concepts, approaches and strategies for the study of living beings.
- [Show abstract] [Hide abstract] ABSTRACT: A novel method improving the performance of spinel LiMn2O4 at high temperature is studied. The copolymer was put into the interspaces of the LiMn2O4 electrode layer prepared by maleic anhydride and acrylamide for decorating LiMn2O4, involving groups to compound with the manganese-ion. It is found that with the act of modification of the functional copolymer, the 45th discharge capacity was improved at 55 °C from 56.8 to 81.4 mAh g−1 on the LiMn2O4 electrode. Fourier transformed infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron micrographs (SEM), inductively coupled plasma atomic emission spectrometry (ICP-AES) and a series of electrochemical measurements have been conducted in this work, and the effects of modification of the polymer layer are discussed.
- [Show abstract] [Hide abstract] ABSTRACT: RNA interference technology is a powerful tool for silencing endogenous or exogenous genes in mammalian cells. Here our results showed that hdm2-siRNA silenced its target mRNA specifically and effectively in human breast cancer cells, reduced tumor cell proliferation and induced apoptotic cell death. Other molecular features modified by hdm2-siRNA included decreased Bcl-2, NF-kappaB, survivin, Ras and Raf levels, elevated p53, p21, BRCA1, Bax, and caspase levels as well as altered expression of other genes. hdm2-siRNA also caused cell cycle arrest at G1 phases with reduction in cyclin and Cdk proteins. In addition, hdm2-siRNA displayed in vivo antitumor activity and increased therapeutic effectiveness of mitomycin in MCF-7 xenografts. Thus, hdm2-siRNA may be a promising gene-specific drug for the treatment of human breast cancer and other tumors.
- [Show abstract] [Hide abstract] ABSTRACT: The energy storage of activated carbon modified with a semiconducting oxide TiO2 is studied. The composite was prepared by mixing nanosize TiO2 and activated carbon through a means of ultrasonic vibration in ethanol solution for 30min. It was found that with modification of TiO2, the specific capacitance of activated carbon measured at 0.65mA/cm2 was increased from 47.2 to 63.1Fg−1. This method is unique in comparison the conventional method because it uses semiconducting TiO2 other than electrochemically active materials such as RuO2. The later has been adopted to make electrochemical-double-layer hybrid supercapacitors, however, the former is attributed to a pure double-layer supercapacitor.