Simultaneous electronic and the magnetic excitation of a ferromagnet by intense THz pulses

The speed of magnetization reversal is a key feature in magnetic data storage. Magnetic fields from intense THz pulses have been recently shown to induce small magnetization dynamics in Cobalt thin film on the sub-picosecond time scale. Here, we show that at higher field intensities, the THz electric field starts playing a role, strongly changing the dielectric properties of the cobalt thin film. Both the electronic and magnetic responses are found to occur simultaneously, with the electric field response persistent on a time scale orders of magnitude longer than the THz stimulu

Synthetic versus biological mesh-related erosion after laparoscopic ventral mesh rectopexy. A systematic review

Purpose: This review reports the incidence of mesh-related erosion after ventral mesh rectopexy to determine whether any difference exists in the erosion rate between synthetic and biological mesh. Methods: A systematic search of the MEDLINE and the Ovid databases was conducted to identify suitable articles published between 2004 and 2015. The search strategy capture terms were laparoscopic ventral mesh rectopexy, laparoscopic anterior rectopexy, robotic ventral rectopexy, and robotic anterior rectopexy. Results: Eight studies (3,956 patients) were included in this review. Of those patients, 3,517 patients underwent laparoscopic ventral rectopexy (LVR) using synthetic mesh and 439 using biological mesh. Sixty-six erosions were observed with synthetic mesh (26 rectal, 32 vaginal, 8 recto-vaginal fistulae) and one (perineal erosion) with biological mesh. The synthetic and the biological mesh-related erosion rates were 1.87% and 0.22%, respectively. The time between rectopexy and diagnosis of mesh erosion ranged from 1.7 to 124 months. No mesh-related mortalities were reported. Conclusion: The incidence of mesh-related erosion after LVR is low and is more common after the placement of synthetic mesh. The use of biological mesh for LVR seems to be a safer option; however, large, multicenter, randomized, control trials with long follow-ups are required if a definitive answer is to be obtained

Transanal minimally invasive surgery for rectal lesions

Background and Objectives: Transanal minimally invasive surgery (TAMIS) has emerged as an alternative to transanal endoscopic microsurgery (TEM). The authors report their experience with TAMIS for the treatment of mid and high rectal tumors. Methods: From November 2011 through May 2016, 31 patients (21 females, 68%), with a median age of 65 years who underwent single-port TAMIS were prospectively enrolled. Mean distance from the anal verge of the rectal tumors was 9.5 cm. Seventeen patients presented with T1 cancer, 10 with large adenoma, 2 with gastrointestinal stromal tumor (GIST) and 2 with carcinoid tumor. Data concerning demographics, operative procedure and pathologic results were analyzed. Results: TAMIS was successfully completed in all cases. In 4 (13%) TAMIS was converted to standard Park’s transanal technique. Median postoperative stay was 3 days. The overall complication rate was 9.6%, including 1 urinary tract infection, 1 subcutaneous emphysema, and 1 hemorrhoidal thrombosis. TAMIS allowed an R0 resection in 96.8% of cases (30/31 cases) and a single case of local recurrence after a large adenoma resection was encountered. Conclusion: TAMIS is a safe technique, with a short learning curve for laparoscopic surgeons already proficient in single-port procedures, and provides effective oncological outcomes compared to other techniques

Temporal and spectral shaping of broadband terahertz pulses in a photoexcited semiconductor

Transmission through a photoexcited semiconductor is used to temporally and spectrally shape a terahertz (THz) pulse. By adjusting the optical pump-THz probe delay, we experimentally introduce a polar asymmetry in the pulse profile as large as 92%. To shape the spectrum, we apply the same technique after strongly chirping the terahertz pulse. This leads to significant reshaping of the spectrum resulting in a 52% upshift of its median value. The pulse shaping techniques introduced here are of particular importance for temporal and spectral shape-sensitive THz nonlinear experiment

Terahertz Faraday rotation in a magnetic liquid: High magneto-optical figure of merit and broadband operation in a ferrofluid

We report on the demonstration of a high figure of merit (FOM) Faraday rotation in a liquid in the terahertz (THz) regime. Using a ferrofluid, a high broadband rotation (11 mrad/mm) is experimentally demonstrated in the frequency range of 0.2–0.9 THz at room temperature. Given the low absorption of the liquid, a high magneto-optical figure of merit (5-16 rad.cm/T) is obtained

Terahertz dipole nanoantenna arrays: resonance characteristics

Resonant dipole nanoantennas promise to considerably improve the capabilities of terahertz spectroscopy, offering the possibility of increasing its sensitivity through local field enhancement, while in principle allowing unprecedented spatial resolutions, well below the diffraction limit. Here, we investigate the resonance properties of ordered arrays of terahertz dipole nanoantennas, both experimentally and through numerical simulations. We demonstrate the tunability of this type of structures, in a range (∼1–2 THz) that is particularly interesting and accessible by means of standard zinc telluride sources. We additionally study the near-field resonance properties of the arrays, finding that the resonance shift observed between near-field and far-field spectra is predominantly ascribable to ohmic damping

Terahertz magnetic modulator based on magnetically clustered nanoparticles

Random orientation of liquid-suspended magnetic nanoparticles (Ferrofluids) gives rise to a zero net magnetic orientation. An external magnetic field tends to align these nanoparticles into clusters, leading to a strong linear dichroism on a propagating wave. Using 10 nm-sized Fe3O4, we experimentally realize a polarization-sensitive magnetic modulator operating at terahertz wavelengths. We reached a modulation depth of 66% using a field as low as 35 mT. The proposed concept offers a solution towards fundamental terahertz magnetic modulators

Effect of rapid solidification on microstructure, creep resistance and thermal properties of Sn-10 wt.% Sb- 3 wt.% X ( X= In, Ag, Bi and Zn) lead-free solder alloys

The harmful effects of lead on the environment and human health, coupled with the threat of legislation, have prompted a serious search of lead-free solders for electronic packaging applications. The melt-spinning processes of ternary Sn-10 wt.%Sb-3 wt.%X (X=In, Ag, Bi and Zn) were analyzed using x-ray diffractometer (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Vickers hardness tester (HV). The investigation showed that, the addition of a small amount of the third element enhances the ductility of the Sn–10 wt. % Sb lead-free solder due to the formation of a fine, homogeneous ternary microstructure. It is concluded that, the addition of 3.0 wt% Ag improves the grain size of the ternary microstructure. The fine precipitates from SnSb intermetallic compound suppresses the coarsening of the ternary structure and thus enhances solder ductility. Structural and microstructural analysis revealed that the origin of change in mechanical behaviors was due to refined beta-Sn grains and formation of intermetallic compounds(IMCs) SnSb, InSn19, ?-In3Sn and Ag3Sn. The results indicated that the melting point of Sn-10Sb-3 wt.% Ag and Sn-10 wt.%Sb- 3 wt.% Zn alloys reduced to 230 and 240 ?C respectively. In particular, the zinc addition at 3 wt.% is the most effective in improving solder ductility and good creep resistance correlated to a fine grain size and complete soluble of SnSb IMC particles in the ?-Sn matrix