The photochemical and thermal cis-to-trans isomerization of aromatic azo groups covalently bonded within polymers and its practical consequences as well as some other recent applications are reviewed. The kinetics and mechanism of the isomerization of azo polymers are briefly presented, and then several recent developments in azo polymers research are discussed. They include liquid crystallinity, nonlinear optical properties, monolayer assemblies, and the lightinduced birefringence and dichroism. Some of the phase transitions of liquid-crystalline azo polymers can be induced photochemically by the azo groups isomerization. Second-order optical nonlinearity can be obtained in polymers with donorand acceptor-substituted azo groups. Using the Langmuir-Blodgett technique, azo polymer monolayers can be built and used as "command surfaces" of liquid-crystal films. The light-induced birefringence is a reorientation phenomenon which is a consequence of the trans-cis-trans isomerization. Future possible applications for a variety of practical devices, such as display devices, optical modulators, optical waveguides, holography, and reversible optical storage are mentioned.

DNA N-methyladenine (6mA) modification is the most prevalent DNA modification in prokaryotes, but whether it exists in human cells and whether it plays a role in human diseases remain enigmatic. Here, we showed that 6mA is extensively present in the human genome, and we cataloged 881,240 6mA sites accounting for ∼0.051% of the total adenines. [G/C]AGG[C/T] was the most significantly associated motif with 6mA modification. 6mA sites were enriched in the coding regions and mark actively transcribed genes in human cells. DNA 6mA and N-demethyladenine modification in the human genome were mediated by methyltransferase N6AMT1 and demethylase ALKBH1, respectively. The abundance of 6mA was significantly lower in cancers, accompanied by decreased N6AMT1 and increased ALKBH1 levels, and downregulation of 6mA modification levels promoted tumorigenesis. Collectively, our results demonstrate that DNA 6mA modification is extensively present in human cells and the decrease of genomic DNA 6mA promotes human tumorigenesis.

ethyl]ethylamino]-4-nitroazobenzene] (pDRIA) is used as an example to demonstrate the ability of amorphous high-Tg azoaromatic-containing polymers to reversibly store optical information. Writing, reading, erasing, and rewriting processes are performed using laser beams on a pDRIA film. This ability is based on the well-known trans-cis-trans isomerization process which was previously studied on liquid-crystalline polymers containing azoaromatic groups. Liquid crystallinity is not a necessary condition for optical storage. As well, erasing can be performed optically, eliminating the need to heat the polymer sample. The writing and erasing are statistical processes, and the level of optical anisotropy induced depends on the photon flux directed at the sample. The time evolution of the writing process is investigated. A computer simulation of these processes is performed taking into account a relaxation process in which some of the reoriented trans molecules are randomized by thermal motion. The computer model replicates the general features of the optical storage processes. Possible applications and future work on this class of polymers are also discussed.

We present a tool that combines fast mapping, error correction, and de novo assembly (MECAT; accessible at https://github.com/xiaochuanle/MECAT) for processing single-molecule sequencing (SMS) reads. MECAT's computing efficiency is superior to that of current tools, while the results MECAT produces are comparable or improved. MECAT enables reference mapping or de novo assembly of large genomes using SMS reads on a single computer.