Experimental and numerical study of different mode-locking techniques in holmium fiber laser with a ring cavity.

Experimental and numerical study has been performed for three techniques of mode-locking in all-fiber Holmium laser. We have compared the fundamental repetition rate pulsed generation for mode-locking based on: nonlinear polarization evolution, polymer-free single-walled carbon nanotubes, and hybrid mode-locking. Experimental and numerical simulation results demonstrated the shortest pulse duration and maximum spectrum width for mode-locking based on the nonlinear polarization evolution: 1.

Dumbbell-Shaped Ho-Doped Fiber Laser Mode-Locked by Polymer-Free Single-Walled Carbon Nanotubes Saturable Absorber.

We propose a simple dumbbell-shaped scheme of a Holmium-doped fiber laser incorporating a minimum number of optical elements. Mode-locking regimes were realized with the help of polymer-free single-walled carbon nanotubes (SWCNTs) synthesized using an aerosol (floating catalyst) CVD method. We show that such a laser scheme is structurally simple and more efficient than a conventional one using a ring cavity and a similar set of optical elements.

Expression of the NUP153 and YWHAB genes from their canonical promoters and alternative promoters of the LINE-1 retrotransposon in the placenta of the first trimester of pregnancy.

The placenta has a unique hypomethylated genome. Due to this feature of the placenta, there is a potential possibility of using regulatory elements derived from retroviruses and retrotransposons, which are suppressed by DNA methylation in the adult body. In addition, there is an abnormal increase in the level of methylation of the LINE-1 retrotransposon in the chorionic trophoblast in spontaneous abortions with both normal karyotype and aneuploidy on different chromosomes, which may be associated with impaired gene transcription using LINE-1 regulatory elements.