Optimization of fs-laser-induced voxels in nonlinear materials via over-correction of spherical aberration.

In this Letter, over-correction of spherical aberration is used to counteract nonlinear effects such as Kerr self-focusing and plasma effects, resulting in more spherical and small-sized femtosecond laser-inscribed voxels within nonlinear materials. By strategically redirecting marginal focusing rays toward the beginning of the laser modification zone, the induced plasma prevents any rays from causing a structural modification beyond this zone, irrespective of any focus elongation caused by nonlinear effects. The method has been effectively validated across a range of materials, including ZnS, ZnSe, BIG, GeS, and SiO.

The nucleoporin Nup153 is the anchor for Kif1a during basal nuclear migration in brain progenitor cells.

Radial glial progenitors (RGPs) are highly elongated epithelial cells that give rise to most stem cells, neurons, and glia in the vertebrate cerebral cortex. During development, the RGP nuclei exhibit a striking pattern of cell-cycle-dependent oscillatory movements known as interkinetic nuclear migration (INM), which we previously found to be mediated during G1 by the kinesin Kif1a and during G2 by cytoplasmic dynein, recruited to the nuclear envelope by the nucleoporins RanBP2 and Nup133. We now identify Nup153 as a nucleoporin anchor for Kif1a, responsible for G1-specific basal nuclear migration, providing a complete model for the mechanisms underlying this basic but mysterious behavior, with broad implications for understanding brain development.

10 W, 2 mJ-level ns all-fiber amplifier at 2.8 µm.

In this Letter, we demonstrate a single-stage erbium-doped fluoride fiber amplifier composed of two spliced large core fibers with respective diameters of 85 and 130 µm. An optical parametric generator (OPG) operating at a 5 kHz repetition rate, and providing ∼2 ns pulse duration, and an average output power of 500 mW at a wavelength of 2.8 µm was used as a seed source.

Nanoscale Chemical Imaging of Amyloid Fibrils in Water Using Total-Internal-Reflection Tip-Enhanced Raman Spectroscopy.

Total-internal-reflection tip-enhanced Raman spectroscopy (TIR-TERS) imaging of amyloid-β (Aβ-L34T) fibrils is performed with nanoscale spatial resolution in water, using TERS tips fabricated by bipolar electrodeposition. Ideal experimental parameters are corroborated by both theoretical simulations and TIR-TERS measurements. TIR-TERS imaging reveals the predominant parallel β-sheet secondary structure of Aβ-L34T fibrils as well as the nanoscale spatial distribution of tyrosine, histidine, and phenylalanine aromatic amino acids.