TGF-β1 induction of the adenine nucleotide translocator 1 in astrocytes occurs through Smads and Sp1 transcription factors

Background  

The adenine nucleotide translocator 1 (Ant1) is an inner mitochondrial membrane protein involved with energy mobilization during oxidative phosphorylation. We recently showed that rodent Ant1 is upregulated by transforming growth factor-beta (TGF-β) in reactive astrocytes following CNS injury. In the present study, we describe the molecular mechanisms by which TGF-β1 regulates Ant1 gene expression in cultured primary rodent astrocytes.     

Optical parametric generation in CdSiP2 at 6.125 μm pumped by 8 ns long pulses at 1064 nm

A 21.4 mm long noncritically cut CdSiP2 crystal, pumped by 8 ns pulses at 1064 nm in a double-pass configuration for pump, signal, and idler, generated 523 μJ, 5.8 ns idler pulses at 6.125 μm. The average power of 52.3 mW at the repetition rate of 100 Hz is the highest ever achieved at such wavelengths with direct down conversion from the 1 μm spectral range.     

Optical parametric generation in CdSiP2

We report efficient generation of picosecond pulses in the near- and mid-IR in the new nonlinear material CdSiP(2) pumped at 1.064 μm by an amplified mode-locked Nd:YVO(4) laser at a 100 kHz repetition rate. By using single-pass optical parametric generation in 8-mm-long crystal cut for type I(e→oo) noncritical phase matching, an average idler power of 154 mW at 6.204 μm together with 1.16 W of signal at 1.282 μm has been obtained for 6.1 W of pump at photon conversion efficiencies of 15% and 23%, respectively. Signal pulse durations of 6.36 ps are measured for 9 ps pump pulses.     

Gaussian- versus flat-top-pumping of a mid-IR ZGP RISTRA OPO

The influence of the pump intensity profile on the performance of a mid-IR ZGP RISTRA OPO at 6.45???m is studied for a flat-top pump profile and compared to a Gaussian pump distribution at the same pump peak fluence of 0.81?J/cm². Due to a coherent beam transformation a flat-top pump beam with a plane wavefront and excellent beam quality of M ²??1.25 is generated. The output of up to 5?mJ pulse idler energy (0.5?W average idler power) is identical in both cases, showing that flat-top pumping allows a reduction of the OPO crystal volume by 55?% while still maintaining a good output beam quality of M ²<2.7 for the idler and M ²<2.5 for the signal. The experimental results are compared to the SNLO RISTRA model and the limitations of the model are discussed.     

Narrowband, mid-infrared, seeded optical parametric generator based on non-critical CdSiP2 pumped by 120-ps, single longitudinal mode 1,064 nm pulses

In this work, we present low-threshold, efficient optical parametric generation in CdSiP₂ pumping at 1,064 nm with 120-ps-long, single longitudinal and transverse mode pulses at 230-kHz repetition rate provided by a microchip passively Q-switched master-oscillator power amplifier laser system. Seeding at the signal wavelength with a laser diode, we generated bandwidth-limited idler pulses at 6,100 nm.     

Observation of a two level thermal conductivity in the low-dimensional materials

The recent theoretical one-dimensional models display invariably anomalous thermal conductivity. Thermal conductivity of several low-dimensional crystalline systems has been investigated using our new techniques. The results show that for most of the measured materials in the high temperature range the thermal conductivity is composed of two extremes: a low- and a high-conductive state. The effective thermal conductivity jumps abruptly between these two states giving rise to apparent discontinuities or “spikes”.     

Compact, 1.5 mJ, 450 MHz, CdSiP2 picosecond optical parametric oscillator near 6.3 μm

We report a compact, efficient, high-energy, and high-repetition-rate mid-IR picosecond optical parametric oscillator (OPO) based on the new nonlinear material CdSiP(2) (CSP). The OPO is synchronously pumped by a master oscillator power amplifier system at 1064.1 nm, providing 1 μs long macropulses constituting 8.6 ps micropulses at 450 MHz, and it can be tuned over 486 nm across 6091-6577 nm, covering the technologically important wavelength range for surgical applications. Using a compact (～30 cm) cavity and improved, high-quality nonlinear crystal, idler macropulse energy as high as 1.5 mJ has been obtained at 6275 nm at a photon conversion efficiency of 29.5%, with >1.2 mJ over more than 68% of the tuning range, for an input macropulse energy of 30 mJ. Both the signal and idler beams are recorded to have good beam quality with a Gaussian spatial profile, and the extracted signal pulses are measured to have durations of 10.6 ps. Further, from the experimentally measured transmission data at 1064 nm, we have estimated the two-photon absorption coefficient of CSP to be β=2.4 cm/GW, with a corresponding energy bandgap, E(g)=2.08 eV.     

Mid-infrared ZnGeP2 parametric oscillator directly pumped by a pulsed 2 microm Tm-doped fiber laser

We have demonstrated what we believe to be the first mid-infrared optical parametric oscillator (OPO) pumped directly by a pulsed Tm-doped fiber laser. The Tm-fiber pump laser produces 30 ns pulses with a repetition rate of 30 kHz at a wavelength of 2 microm. The ZnGeP2 (ZGP) OPO produces 20 ns mid-IR pulses in the 3.4-3.9 microm and 4.1-4.7 microm spectral regions simultaneously. More than 658 mW of mid-IR output power has been generated with a total OPO slope efficiency greater than 35%.     

Narrow-bandwidth, mid-infrared, seeded optical parametric generation in 90° phase-matched CdSiP₂ crystal pumped by diffraction limited 500 ps pulses at 1064 nm

Low-threshold, efficient optical parametric generation at ～6100 nm is demonstrated using CdSiP₂ nonlinear crystal at 1 to 10?kHz repetition rates with relatively long 500?ps pump pulses at 1064?nm. Maximum single pulse energy of 8.7?μJ and average power of 79?mW are achieved for the idler. Seeding at the signal wavelength is employed using a distributed feedback laser diode, which enables approximately tenfold narrowing of the idler bandwidth down to less than 1?nm.     

Phase-matching properties and refined Sellmeier equations of the new nonlinear infrared crystal CdSiP2

We directly measured the second harmonic generation and difference frequency generation phase-matching directions of the nonlinear crystal CdSiP(2) until 9.5 μm using the sphere method. The simultaneous fit of the experimental angular data allowed the Sellmeier equations of the ordinary and extraordinary principal refractive indices to be refined over the entire transparency range of the crystal.