Impact of the dipole contribution on the terahertz emission of air-based plasma induced by tightly focused femtosecond laser pulses.

The present paper studies the generation mechanism of terahertz (THz) radiation from tightly focused femtosecond laser pulses in a gas medium. We measured the angular radiation pattern under different focusing conditions and observed that, with the deepening of focus, the angular radiation pattern changes and optical-to-THz conversion efficiency increases. The analysis of the observed phenomena led to the assumption that the dipole radiation prevails in most cases despite the existing conception regarding the dominating role of the quadrupole mechanism of radiation. Based on these assumptions, the transient photocurrent theory of the phenomenon presented in this paper was developed by us and used for the numerical fit of the experimental data.

Hybrid revascularization in multivessel coronary artery disease.

OBJECTIVES: Minimally invasive hybrid revascularization (MIHR) by means of the left mammary artery on the left anterior descending artery [minimally invasive direct coronary artery bypass (MIDCAB)] combined with percutaneous coronary interventions (PCI) stenting may be an alternative to conventional coronary artery bypass grafting through sternotomy or multiple PCI. The purpose of this study is to retrospectively evaluate the long-term outcomes of this strategy. METHODS: Since May 1997 up to January 2011, 810 MIDCAB have been performed as isolated revascularization in 644 patients. Since 2004, MIDCAB, as a part of hybrid revascularization, was associated with PCI in 166 patients. RESULTS: In the MIDCAB group, mean age was 64.6 ± 12.0, with 83.8% males. Two-vessel disease was 62.4%, three-vessel disease 37.6%. Overall mortality was 0.24%, perioperative acute myocardial infarction-1.6%, early reoperation-0.74%, reopening for bleeding-1.2%, case rate of haemotrasfusion-3.1%, with a mean hospital postoperative stay of 4 ± 2.5 days. Postoperative angiographic control prior to PCI and in symptomatic patients showed patent left internal mammary artery in 100% of cases. PCI was performed in 166 patients, 64.2% before MIDCAB and 35.8% after surgery (interval 2.2 ± 1.3 months). The mean follow-up in the MIDCAB group was 8.4 ± 3.2 years. In the MIHR group, at the mean follow-up of 4.5 ± 2.3 years, freedom from related cardiac death was 93% with freedom from cardiac reintervention of 83%. CONCLUSIONS: Our 13-year experience with MIDCAB demonstrates that the operation is safe and associated with a very low incidence of early and late complications. The hybrid approach provided excellent long-term outcome in terms of freedom from cardiac death and reoperation. Accurate patient selection, as well the timing of the hybrid procedure, is mandatory to optimize surgical and PCI results.

Admissible equilibria of non-neutral plasmas in a Malmberg-Penning trap.

A "parallel current constraint" is derived, that in combination with the Poisson equation allows one to select admissible equilibria of non-neutral plasmas in a Malmberg-Penning trap in the presence of a nonuniform and nonaxisymmetric magnetic field. Asymmetry-induced currents (analogous to the Pfirsch-Schlüter currents in Tokamaks) appearing in a non-neutral plasma even in the absence of magnetic drifts are explicitly computed in the case of a uniformly tilted magnetic field.

Single-suture line placement of a pericardial stentless valve.

OBJECTIVE: Implantation of bioprostheses in the supra-annular position with the single suture line was first applied by O'Brien to porcine stentless valves. The aim of this study was to evaluate the clinical performance of the Pericarbon Freedom stentless bioprosthesis (Sorin Biomedica Cardio, Saluggia, Italy) implanted in supra-annular position with the single-suture line technique. The single-suture approach for the Pericarbon Freedom stentless bioprosthesis is obtained by trimming away all the extra tissue of the valve inflow side and scalloping the outflow side. METHODS: Between February 2002 and August 2004, a total of 65 consecutive patients at our institution (48% male, mean age 69 +/- 12 years) underwent aortic valve replacement with Pericarbon Freedom stentless bioprostheses implanted with a single suture line. Most recurrent etiology was senile degeneration (80%). Pericarbon Freedom 25-mm and 27-mm valves were the most frequently implanted. Thirty patients had concomitant procedures (mainly coronary artery bypass grafting, 16 patients). Overall crossclamp time was 76 +/- 21 minutes. RESULTS: All patients survived intervention. One patient died early of multiorgan failure (postoperative day 16). There were 4 early non-valve-related complications and no late complications at a mean follow-up of 491 +/- 270 days. Four patients showed trivial central prosthetic regurgitation at intraoperative transesophageal echocardiography; among these cases, only 1 was confirmed at 6-month transthoracic echocardiography. At postoperative echocardiographic assessment, mean pressure gradient for the 25- through 29-mm size group was 10.2 +/- 7.1 mm Hg, and peak pressure gradient was 18.1 +/- 12.3 mm Hg. CONCLUSION: Our initial experience combined a well-established supra-annular implantation technique with the Pericarbon Freedom stentless bioprosthesis, a latest-generation pericardial stentless valve. The combination showed excellent results in terms of safety and reliability, although this technique required adequate experience. Clinical outcomes are similar to those obtained with other techniques, with satisfactory hemodynamic performance.