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We present a rapid-scan, time-domain terahertz spectrometer employing femtosecond Er:fiber technology and an acousto-optic delay with attosecond precision, enabling scanning of terahertz transients over a 12.4-ps time window at a waveform refresh rate of 36 kHz, and a signal-to-noise ratio of 1.7×105/√Hz. Our approach enables real-time monitoring of dynamic THz processes at unprecedented speeds, which we demonstrate through rapid 2D thickness mapping of a spinning teflon disc at a precision of 10 nm/√Hz. The compact, all-optical design ensures alignment-free operation even in harsh environments. [ABSTRACT FROM AUTHOR]

Ultrafast charge transport in strongly biased semiconductors is at the heart of high-speed electronics, electro-optics and fundamental solid-state physics. Intense light pulses in the terahertz spectral range have opened fascinating vistas. Because terahertz photon energies are far below typical electronic interband resonances, a stable electromagnetic waveform may serve as a precisely adjustable bias. Novel quantum phenomena have been anticipated for terahertz amplitudes, reaching atomic field strengths. We exploit controlled (multi-)terahertz waveforms with peak fields of 72 MV cm−1 to drive coherent interband polarization combined with dynamical Bloch oscillations in semiconducting gallium selenide. These dynamics entail the emission of phase-stable high-harmonic transients, covering the entire terahertz-to-visible spectral domain between 0.1 and 675 THz. Quantum interference of different ionization paths of accelerated charge carriers is controlled via the waveform of the driving field and explained by a quantum theory of inter- and intraband dynamics. Our results pave the way towards all-coherent terahertz-rate electronics. [ABSTRACT FROM AUTHOR]

Purpose: Ex vivo lung perfusion (EVLP) has been proven to provide the opportunity to evaluate and optimise unacceptable donor lungs prior to transplantation. We report on the initial clinical results of a prospective study of lung transplantation after ex vivo perfusion. Methods and Materials: All donors lungs who are deemed unacceptable by our standard criteria and meet the inclusion criteria of our prospective non-randomized clinical study are evaluated with ex vivo lung perfusion using acellular Steen Solution for two to four hours. Lungs showing a ΔPO2 of at least 350 mmHg between arterial and venous solution with stable or improving functional parameters are accepted for transplantation. Results: From 3/2010 – 10/2010 10 lungs were evaluated ex vivo. Mean donor age was 45 years (range 16-58). Mean donor PaO2 at FiO2 1,0/PEEP 5 was 206±50 mmHg. 4 lungs, all with trauma history did not improve and were not used. 6 lungs improved to a ΔPO2 of more than 350 mmHg. Mean PaO2 in those lungs was 468±34 mmHg after EVLP. These lungs were transplanted with a mean total ischemic time of 570 minutes. Mean recipient age was 42 years (range 18-66) Diagnoses were fibrosis (n=2), COPD (n=2), CF (n=1), SPH (n=1). 5 recipients had a PGD score 0 at 24 hours posttransplant. The patient with secondary pulmonary hypertension was left on a planned prolonged ECMO postoperatively for hemodynamic reasons showing good lung function. Median intubation time was 2 days. 30 day mortality was 0%. Conclusions: Ex lung perfusion is a safe and effective method to evaluate and optimise nonacceptable donor lungs. In the setting of an already very liberal use of marginal donor organs we were able to transplant 6 additional lungs which would not have been used otherwise with excellent short term results. [ABSTRACT FROM AUTHOR]