Abstract. CD44 is a transmembrane receptor for hyaluronic acid. CD44 pre-mRNA contains 19 exons, 9 of which are alternatively spliced. Among the CD44 spliced variants, the v4-7 variant, one of the v6 exon-containing isoforms that contains variable exon 4, 5, 6 and 7, confers metastatic potential to nonmetastatic cells. Splicing of CD44 and the function of CD44 isoforms are different in breast cancer cells. hnRNP A1 is a ubiquitously expressed protein with an inhibitory function in pre-mRNA splicing. We showed that CD44v6 isoform, which includes all of the v6-containing mRNA isoforms, had the highest expression level in non-metatatic breast cancer cells (MCF7) when compared to the level in metastatic breast cancer cells (MDA-MB-231) and normal breast cells (MCF10A). Furthermore we showed that hnRNP A1 knockdown regulated splicing of CD44 differently in breast cancer cells. We showed here that CD44 isoform expression is completely different in MDA-MB-231 cells than that in MCF7 and MCF10A cells, whereas MCF7 and MCF10A cells had a similar expression pattern of CD44 isoforms. RT-PCR analysis of CD44v6 showed that MCF7 and MCF10A cells predominantly expressed the c5v6v7v8v9v10c6 isoform. However, in addition to this isoform, MDA-MB-231 cells also expressed the c5v6v8v9v10c6 and c5v6c6 isoforms. We also found that knockdown of hnRNP A1 significantly reduced the expression of c5v6v7v8v9v10c6 and c5v6v8v9v10c6, and promoted the expression of c5v6c6. hnRNP A1 knockdown significantly induced cell death. In addition, hnRNP A1 knockdown induced a decrease in cell invasion in the MDA-MB-231 cells. Our results indicate that the knockdown of hnRNP A1 has a specific function on the splicing of CD44 in breast cancer cells.
Composite insulator was widely used in the power grid because its excellent performance. Aging issue of composite insulators was appeared with the long-term operating. The internal structure of silicone rubber may be changed with the broken of macromolecular chains of silicone rubber, because long-term operating in the environments of surface discharge, ultraviolet, pollution and other harsh conditions. In order to study the aging characteristics of composite insulator at the different operating life, the components and thermal stability were analyzed using fourier transform infrared spectroscopy (FTIR) and thermal gravimetric analysis (TGA) respectively. The results of FTIR showed that silicon rubber composition in composite insulator changed slightly with different operating life, especially in the internal surface. However, the absorption peaks of Si-CH3 and Si-O-Si on external surface of the insulator were decreased obviously with operating life longer. The thermal gravimetric analysis results showed that the thermostability of composite insulator was almost not changed with different operating life. The temperature of 5% weightlessness was between 320°C to 335°C. It illustrated that the composite insulator had a good thermostability at room temperature and qualitative change wouldn't occur for a long time laying aside. The study of the aging characteristics of composite insulators will provided the reference for performance evaluation of running composite insulators.
Reducing the network energy consumption and increasing the lifetime of network are important content for wireless sensor network. LEACH is an adaptive routing algorithm with low consumption for wireless sensor network. However there are many shortcomings in LEACH routing algorithm such as too much energy consumption of cluster heads and uneven clustering each round. This paper puts forward a new improved algorithm named H-LEACH to solve the problem above. It lets the nodes holding more energy have the high possibility to become cluster-heads through a threshold and constraints the number of clusters each round at the same time so that it can balance the energy distribution and reduce energy cost. Simulation results show that H-LEACH is more energy-efficient than LEACH protocol.
It is especially important to save energy and prolong the network lifetime because the WSN nodes energy is limited. Optimizing the routing algorithm for WSN is one of the important ways to reduce energy consumption. LEACH routing protocol is the first cluster-based routing protocol for wireless sensor networks. But LEACH have some deficiencies, such as agreement of uneven clustering, the nodes energy imbalance, frequent clustering and consume too much energy. The paper proposes an improved LEACH protocol to solve the above problem. It takes the residual energy of the nodes into account when nodes selected the cluster-head so that the nodes that hold high-energy have the high possibility to be selected as cluster-head. The improved algorithm uses the incomplete clustering which does not need to cluster every round but interval cluster. Simulation results show that the improved LEACH protocol effectively increases the nodes energy utilization and extends the network lifetime.
With the improvement of living standards, people's demands for culture are increasingly high. Based on the research of Android platform and Cloud computing technology, it builds a Cultural Compound system based on Android platform in this paper. It utilizes Cloud computing technology to build a network management unit, uses AMAP to provide the users location information. It can provide users to search the surrounding nine different kinds of cultural venues. Meanwhile, it has a lot of features. Especially, cultural venues can push their information to the users through this system. This system can allow people more convenient to get cultural information through mobile phone at any time and at any place to meet peoples spiritual needs.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.