Avoiding neuromuscular stimulation in liver irreversible electroporation using radiofrequency electric fields

Electroporation based treatments typically consist in applying high voltage dc pulses. As an undesired side effect, these dc pulses cause electrical stimulation of excitable tissues such as motor nerves. In the present in vivo study, it was explored the use of bursts of sinusoidal voltage in the frequency range from 50 kHz to 2 MHz to induce irreversible electroporation (IRE) whilst avoiding neuromuscular stimulation. Series of 100 dc pulses or sinusoidal bursts, both with an individual duration of 100 μs, were delivered to rabbit liver through thin needles in a monopolar electrode configuration and thoracic movements were recorded with an accelerometer. Tissue samples were harvested three hours after treatment and later postprocessed to determine the dimensions of the IRE lesions. Thermal damage due to Joule heating was ruled out via computer simulations. Sinusoidal bursts with a frequency equal or above 100 kHz did not cause thoracic movements and induced lesions equivalent to those obtained with conventional dc pulses when the applied voltage amplitude was sufficiently high. IRE efficacy dropped with increasing frequency. For 100 kHz bursts, it was estimated that the electric field threshold for IRE is about 1.4 kV/cm whereas that of dc pulses is about 0.5 kV/cm.This work was supported by the Ministry of Economy and Competitiveness of Spain through the grant TEC2014-52383-C3-R (TEC2014-52383-C3-2-R and TEC2014-52383-C3-3-R)

Neighborhood Outsiders, Field Insiders: Latino Immigrant Men and the Control of Public Space

 This paper examines how a group of primarily Latino immigrant men claim and control a sought-after and contested public soccer field in a West Los Angeles public park. In contrast to previous studies that took the stability, viability, and visibility of groups, and their claims, as given, this study examines how group boundaries become constructed and taken-for-granted in working out the use and control of public space. As this study reveals, control is premised on creating and sustaining meaningful distinctions between insiders and outsiders, which are far from self-evident in open gatherings. Control is also constructed through the enforcement of informal authority, which is inherently uncertain in public space, especially for stigmatized groups with no formal association to the area. By studying how social organization is repeatedly challenged and reconstructed on the playing field, this paper sheds new light onto how informal claims on public space are made and remade in the contemporary city.