A new approach for the fabrication of a multilayer film assembly is explored, which is based on the alternating assembling of poly(4-vinylpyridine) and poly(acry1ic acid) via hydrogen bonding. The homogeneous multilayer films were characterized by UV-Vis, Xray diffraction and atomic force microscopy (AFM) measurements. The nature of interaction between the two polymers is identified as hydrogen bonding by IR spectroscopy.Organized molecular films, fabricated mainly by Langmuir-Blodgett method and self-assembling techniques, have various potential applications in molecular electronics, optical devices and biomedical applications'). Since Nuzzo and Allara showed the formation of self-assembled monolayers (SAMs) on gold, the field of S A M s has witnessed tremendous progress*. '). The driving force for this self-assembly is based on chemisorption of an active surfactant on a solid surface, e.g., the formation of gold thiolate resulting in SAMs of organosulfur compounds and the in-situ formation of polysiloxane directing SAMs of organosilicon derivatives. Based on coordination bonds between phosphate compounds and transition metal ions like Zr4', Mallouk discovered a new route to prepare simply self-assembled multilayers of diph~sphates~). Six years ago Decher et al. demonstrated the application of ionic attraction to construct multilayer polymer films? However, this assembling technique is developed far beyond in the polymer system, and a wide range of application is found such as in the assembly of nano particles, biomacromolecules and different functional supermolecules6). Very recently, Sagiv et al. successfully achieved selfreplicating amphiphilic monolayers7). Here we report a new approach for the fabrication of a multilayer film on the basis of hydrogen bonds.As it is well known, pyridine and carboxylic acid are good hydrogen bonding complementary partners. Frkchet et al. has built a new type of side-chain supramolecular liquid crystalline aggregates via intermolecular hydrogen bonding between pyridine and carboxylic acid". The complementary partners we used here are poly(4-vinylpyridine) and poly(acry1ic acid).

Developing rapid and diverse microbial mutation tool is of importance to strain modification. In this review, a new mutagenesis method for microbial mutation breeding using the radio-frequency atmospheric-pressure glow discharge (RF APGD) plasma jets is summarized. Based on the experimental study, the helium RF APGD plasma jet has been found to be able to change the DNA sequences significantly, indicating that the RF APGD plasma jet would be a powerful tool for the microbial mutagenesis with its outstanding features, such as the low and controllable gas temperatures, abundant chemically reactive species, rapid mutation, high operation flexibility, etc. Then, with the RF APGD plasma generator as the core component, a mutation machine named as atmospheric and room temperature plasma (ARTP) mutation system has been developed and successfully employed for the mutation breeding of more than 40 kinds of microorganisms including bacteria, fungi, and microalgae. Finally, the prospect of the ARTP mutagenesis is discussed.

Background Increasing evidence has revealed a close relationship between non-coding RNAs and cancer progression. Circular RNAs (circRNAs), a recently identified new member of non-coding RNAs, are demonstrated to participate in diverse biological processes, such as development, homeostatic maintenance and pathological responses. The functions of circRNAs in cancer have drawn wide attention recently. Until now, the expression patterns and roles of circRNAs in hepatocellular carcinoma (HCC) have remained largely unknown. Methods Bioinformatics method was used to screen differentially expressed novel circRNAs in HCC. Northern blotting, qRT-PCR, in situ hybridization (ISH) and RNA-FISH were utilized to analyzed the expression of circRHOT1 in HCC tisues.CCK8, colony formation, EdU assays were used to analyze proliferation of HCC cells. Transwell assay was utilized to analyze HCC cell migration and invasion. FACS was used for apoptosis analysis. Xenograft experiments were used to analyze tumor growth in vivo. Mass spectrum, RNA pulldown, RIP and EMSA was utilized to test the interaction between circRHOT1 and TIP60. RNA-sequencing method was used to analyze the downstream target gene of circRHOT1. Results We identified circRHOT1 (hsa_circRNA_102034) as a conserved and dramatically upregulated circRNA in HCC tissues. HCC patients displaying high circRHOT1 level possessed poor prognosis. Through in vitro and in vivo experiments, we demonstrated circRHOT1 significantly promoted HCC growth and metastasis. Regarding the mechanism, we conducted a RNA pulldown with a biotin-labeled circRHOT1-specific probe and found that circRHOT1 recruited TIP60 to the NR2F6 promoter and initiated NR2F6 transcription. Moreover, NR2F6 knockout inhibited growth, migration and invasion, whereas rescuing NR2F6 in circRHOT1-knockout HCC cells rescued the proliferation and metastasis abilities of HCC cells. Conclusion Taken together, circRHOT1 inhibits HCC development and progression via recruiting TIP60 to initiate NR2F6 expression, indicating that circRHOT1 and NR2F6 may be potential biomarkers for HCC prognosis. Electronic supplementary material The online version of this article (10.1186/s12943-019-1046-7) contains supplementary material, which is available to authorized users.

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