1.6-µm-wavelength dissipative solitons mode-locked fiber laser based on the optimization of passive fibers distribution.

We present the results of numerical simulation of a dissipative solitons mode-locked fiber laser working over 1.6 µm. First, systematic and computationally intensive analysis of high-energy-pulse nonlinear phase shift of a fiber laser was conducted, and we numerically simulated dissipative solitons pulse evolution. In addition, we employed a method named A/B ratio to decrease B-integral by changing the distribution of passive fiber in the ring cavity. This method inhibited the accumulation of nonlinear phase shift and effectively enlarged the pulse energy from 0.8 nJ to 3.6 nJ. Finally, we optimized linear chirp of the pulse by using a designed larger-mode-area fiber, and ultimately a 2.82-kW, 650-fs pulse was obtained.

Controlling ion-sensing specificity of N-amidothioureas: from anion-selective sensors to highly Zn(2+)-selective sensors by tuning electronic effects.

N-Amidothioureas bearing nitro groups showed different sensitivities to various anions, while those with methoxy moieties exhibited the sensitive and selective fluorescence turn-on property for Zn(2+) in aqueous solution and in cells. N-Amidothioureas can therefore be adjusted from anion-selective sensors to Zn(2+)-selective sensors by varying the electronic effects of their substituents.

Synthesis of [12]aneN3-dipeptide conjugates as metal-free DNA nucleases.

In this Letter, a series of macrocyclic polyamine [12]aneN(3)-dipeptide conjugates as a new type of metal-free nucleases were synthesized and fully characterized with (1)H NMR, (13)C NMR, IR, and HR-MS. Results indicate that these conjugates can bind to calf thymus DNA mainly through electrostatic interaction and can cleave the plasmid DNA at 200 µM (pH 7.2, 37°C), with an acceleration of 10(6)-fold via hydrolytic pathway.