Non-thermal plasmas generated at atmospheric pressure are of great interest for biomedical applications related to sterilization and microbial decontamination. These plasmas produce reactive species such as O, N2* and OH radical and atomic O, associated with processes of inactivation of microorganisms and removal of organic materials. In this work we study an electrical discharge capable of generating a plasma plume close to ambient temperature. The discharge is produced between two conducting disks separated by an insulating disk, with a 1 mm central hole through which the operating gas flows. Characteristic voltage-current curves were measured using either air or argon and variable insulator thicknesses between 1 and 10 mm. Also, the discharge emission spectrum was measured.

Los plasmas no térmicos generados a presión atmosférica presentan interés en aplicaciones biomédicas vinculadas a la esterilización y descontaminación microbiana. Este tipo de plasmas produce especies activas como O, N2* y radicales OH, asociadas a procesos de inactivación de microorganismos y a la remoción de materiales orgánicos. En este trabajo se estudia una descarga eléctrica tipo plasma jet capaz de generar una pluma de plasma con temperaturas próximas a la temperatura ambiente. La descarga se produce entre dos discos conductores separados por un disco aislante, con un orificio central de 1 mm a través del cual fluye el gas de operación. Se realizaron mediciones de las curvas características de tensión-corriente empleando aire y argón y variando el espesor del aislante entre 1 y 10 mm. Además, se midió el espectro de emisión de la descarga.

An experimental study of the metallic ion flux in a pulsed copper vacuum arc with an annular anode and operated with an axial magnetic field is presented. It is employed an insulating drift duct surrounded by an external coil which generates an axial magnetic field. Operating the arc under vacuum condition, measurements of the ion flux and the plasma potential at different axial positions along the duct and different magnetic field values are presented. The arc voltage and the total discharge current as functions of the magnetic field intensity are also reported. We find that the decay of the ion flux through the duct walls is not exponential. A simplified model for the ion emission is used in order to obtain an interpretation of the measured ion current for different axial positions and magnetic field strength, and a good agreement with the experimental points is found.

The objective of the present study was to evaluate and quantify fetal risks involved in the administration of cancer chemotherapy during gestation, as well as to assess the long-term effects on the exposed children. In this retrospective, cohort study, we reviewed the records of women aged 15 to 45 years with a diagnosis of malignancy or benign tumors with malignant behavior at three reference services in the State of Rio Grande do Sul, Brazil, from 1990 to 1997. All patients with a diagnosis of pregnancy at any time during the course of the disease were selected, regardless of whether or not they received specific medication. Fetal outcomes of 14 pregnancies with chemotherapy exposure were compared to that of 15 control pregnancies in which these drugs were not used. Long-term follow-up of the exposed children was carried out. Fisher's exact test was used to compare the groups. Continuous variables were compared by the Wilcoxon-Mann-Whitney test. We found an increased rate of prematurity (6/8 vs 2/10; RR: 3.75; CI: 1.02-13.8; P = 0.03) in the exposed group. There was a trend to an increased fetal death rate (4/12 vs 0/10; P = 0.07) in the group exposed to chemotherapy. No malformations were detected in any child, which can be related to our small sample size as well as to the fact that most exposures occurred after the first trimester of pregnancy. Other larger, controlled studies are needed to establish the actual risk related to cancer chemotherapy during pregnancy.