Cathode Sheath Thickness of a Microhollow Cathode Discharge Plasma In Argon High Gas Pressures

In a glow discharge, the sheath region that is formed around the cathode surface has a decisive effect on the generation of plasmas. In order to investigate the sheath structure in an atmospheric pressure plasma, we developed a microhollow cathode discharge (MHCD) device. The MHCD device had a cathode diameter of 0.5 mm and its length of 2.0 mm. The discharge was operated at a discharge voltage and current of -220 V and 15 mA, respectively, up to 20 kPa of He-Ar mixtures. We carried out the visible/UV emission spectroscopy, which enabled us to understand the characteristics in the cathode sheath. It was found that two dimensional emission images attributed to Ar+ ion and neutral atom showed significantly different behavior with increasing gas pressure. By comparing the results obtained by an ionizing sheath theory with experimental ones, the detail of the sheath structure is clarified

Sistema de prevención de riesgos laborales para el control de radiaciones ionizantes en la planta de producción de radioisótopos del Instituto Peruano de Energía Nuclear, propuesta actual

La tesis denominada: “Sistema de Gestión de Prevención de Riesgos Laborales (SGPRL) para el control de radiaciones ionizantes dentro de la Planta de Producción de Radioisótopos (PPR) del Instituto Peruano de Energía Nuclear, propuesta actual”; cuyo problema se ha identificado en la falta de un adecuado Sistema de Gestión de prevención de Riesgos Laborales acordes con la ley N°29783 “Ley de Seguridad y Salud en el Trabajo”, promulgada el 20 de agosto del 2011 y en concordancia con las Normas de Seguridad Protección Radiológica ocupacional del Organismo Internacional de Energía Atómica (OIEA). Esta problemática se expresa en la siguiente pregunta: ¿De qué manera el sistema de prevención de riesgos laborales podrá facilitar el control de radiaciones ionizantes en la Planta de producción de radioisótopos del Instituto Peruano de Energía Nuclear? Ante la problemática se propone la solución a través de la formulación de la hipótesis: El sistema de prevención de riesgos laborales facilita el control de radiaciones ionizantes en la Planta de producción de radioisótopos del Instituto Peruano de Energía Nuclear (IPEN) Este trabajo se ha orientado al siguiente objetivo: Determinar la manera como el sistema de prevención de riesgos laborales podrá facilitar el control de radiaciones ionizantes en la Planta de producción de radioisótopos del Instituto Peruano de Energía Nuclear, alineando este SGPRL con la política de Seguridad y Salud en el Trabajo del IPEN con el planteamiento de estrategias y procedimiento que facilitan el control de dosis de radiaciones ionizantes incorporadas por los Trabajadores Ocupacionalmente Expuestos (TOE) y la prevención de enfermedades ocupacionales a cauda de esta actividad laboral. La investigación es de tipo descriptiva; del nivel descriptivo-explicativo-correlacional; se utilizó los métodos descriptivo, explicativo e inductivo. El diseño es el no experimental. La población y muestra estuvo compuesta por los TOE de la PPRR. El tipo de muestreo aplicado es el muestreo probabilístico. Las técnicas utilizadas para la recopilación de datos fueron a través de las mediciones realizadas por el Laboratorio de Contaminación Interna de la división de Protección Radiológica Ocupacional y Ambiental (PROA). El instrumento utilizado fue la medición in vivo de los TOE. Se aplicaron las siguientes técnicas de análisis de información: análisis documental, indagación, conciliación de datos, tabulación, comprensión de gráficos. Se aplicó las siguientes técnicas de procesamiento de datos: ordenamiento y clasificación, registro manual, proceso computarizado con Excel, Adquisición de datos, Análisis y cálculo de la espectrometría Gama a través del Software GENIE 2000.Tesi

Emission spectroscopy of a microhollow cathode discharge plasma in helium-water gas mixtures

A dc microhollow cathode discharge (MHCD) plasma was generated inflowing helium gas containing water vapor. The cathode hole diameters were 0.3, 0.7, 1.0, and 2.0 mm, each with a length of 2.0 mm. Emission spectroscopy was carried out to investigate the discharge mode and to determine the plasma parameters. For the 0.3-mm cathode, stable MHCDs in an abnormal glow mode existed at pressures up to 100 kPa, whereas for larger diameters, a plasma was not generated at atmospheric pressure. An analysis of the lineshapes relevant to He at 667.8 nm and to Hα at 656.3 nm implied an electron density and gas temperature of 2 × 1014 cm-3 and 1100 K, respectively, for a 100-kPa discharge in the negative glow region. The dependence of the OH band, and Hα intensities on the discharge current exhibited different behaviors. Specifically, the OH spectrum had a maximum intensity at a certain current, while the H atom intensity kept increasing with the discharge current. This observation implies that a high concentration of OH radicals results in quenching, leading to the production of H atoms via the reaction OH + e- → O + H + e-

Association between Histological Types and Enhancement of Dynamic CT for Primary Lung Cancer

The aim of this study was to explore enhancement patterns of different types of primary lung cancers on 2-phase dynamic computed tomography (CT). This study included 217 primary lung cancer patients (141 adenocarcinomas [ADs], 48 squamous cell carcinomas [SCCs], 20 small cell lung carcinomas [SCLCs], and 8 others) who were examined using a 2-phase dynamic scan. Regions of interest were identified and mean enhancement values were calculated. After excluding the 20 SCLCs because these lesions had different clinical stages from the other cancer types, the mean attenuation values and subtractions between phases were compared between types of non-small cell lung carcinomas (NSCLCs) using the Kruskal–Wallis test. Late phase attenuation and attenuation of the late minus unenhanced phase (LMU) of SCCs were significantly higher than those of ADs (p<0.05). To differentiate SCC and AD in the late phase, a threshold of 80.21 Hounsfield units (HU) gave 52.9% accuracy. In LMU, a threshold of 52.16 HU gave 59.3% accuracy. Dynamic lung CT has the potential to aid in differentiating among NSCLC types

Quantification of (–)-Epigallocatechin-3-gallate Inhibition of Anaplastic Thyroid Cancer Cell Line Adhesion and Proliferation Using Real-time Cell Analysis

Anaplastic thyroid cancer (ATC) has a poor prognosis because of immediate metastasis. Several studies in humans and animals have suggested that the ingestion of green tea or its active ingredient (–)-epigallocatechin-3-gallate (EGCG) may decrease the risk of cancer. Using a recently developed real-time cell analysis (RTCA) system, we have shown previously that EGCG inhibits cell migration and the invasion of oral cavity cancers by suppressing matrix metalloproteinases. In the present study we used RTCA to investigate the effects of EGCG on cell adhesion to fibronectin-coated plates using three cancer cell lines: one ATC cell line (TCO-1) and two poorly differentiated oral squamous cell carcinomas (OSCCs) cell lines (SAS and HO-1-u-1; originating from the tongue and floor of the mouth, respectively). EGCG (50µM) inhibited the adhesion of all three cell lines. In addition to its effects on cell adhesion, 50µM EGCG inhibited the cell proliferation of TCO-1 cells. Furthermore, EGCG decreased αV integrin (ITGAV) mRNA levels in all three cell lines, suggesting that EGCG inhibits the cell adhesion and proliferation of OSCC and ATC cells via suppression of integrin expression. Therefore, EGCG represents a useful dietary constituent or a lead compound for counteracting metastasis of oral cavity cancers and thyroid cancers

Surgical Explantation of Transcatheter Aortic Valve Bioprostheses: A Statewide Experience

BACKGROUND: Despite the rapid adoption of transcatheter aortic valve replacement (TAVR) since its initial approval in 2011, the frequency and outcomes of surgical explantation of TAVR devices (TAVR-explant) is poorly understood. METHODS: Patients undergoing TAVR-explant between January 2012 and June 2020 at 33 hospitals in Michigan were identified in the Society of Thoracic Surgeons Database and linked to index TAVR data from the Transcatheter Valve Therapy Registry through a statewide quality collaborative. The primary outcome was operative mortality. Indications for TAVR-explant, contraindications to redo TAVR, operative data, and outcomes were collected from Society of Thoracic Surgeons and Transcatheter Valve Therapy databases. Baseline Society of Thoracic Surgeons Predicted Risk of Mortality was compared between index TAVR and TAVR-explant. RESULTS: Twenty-four surgeons at 12 hospitals performed TAVR-explants in 46 patients (median age, 73). The frequency of TAVR-explant was 0.4%, and the number of explants increased annually. Median time to TAVR-explant was 139 days and among known device types explanted, most were self-expanding valves (29/41, 71%). Common indications for TAVR-explant were procedure-related failure (35%), paravalvular leak (28%), and need for other cardiac surgery (26%). Contraindications to redo TAVR included need for other cardiac surgery (28%), unsuitable noncoronary anatomy (13%), coronary obstruction (11%), and endocarditis (11%). Overall, 65% (30/46) of patients underwent concomitant procedures, including aortic repair/replacement in 33% (n=15), mitral surgery in 22% (n=10), and coronary artery bypass grafting in 16% (n=7). The median Society of Thoracic Surgeons Predicted Risk of Mortality was 4.2% at index TAVR and 9.3% at TAVR-explant (P=0.001). Operative mortality was 20% (9/46) and 76% (35/46) of patients had in-hospital complications. Of patients alive at discharge, 37% (17/37) were discharged home and overall 3-month survival was 73±14%. CONCLUSIONS: TAVR-explant is rare but increasing, and its clinical impact is substantial. As the utilization of TAVR expands into younger and lower-risk patients, providers should consider the potential for future TAVR-explant during selection of an initial valve strategy

Hope in Adult Patients with Chronic Disease: Qualitative Study.

To identify the sources of hope for patients with chronic disease, a semi - structured interview was conducted with patients middle-aged and older, whose disease types and levels of activities of daily living limitations varied. Six patience - three with chronic kidney disease, one with rheumatoid arthritis, one with spinal cord injury, and another with lumbar spinal canal stenosis - were interviewed by a psychologist and an internist. It was determined that their sources greatly differed depending on individual circumstances, such as types and severity of disease, sources of joy and happiness, family structure, employment status, relationship with friends, etc. However, it also showed a stylization of hope dependent on individual experience; in other words, there was a tendency for patients to redefine their source of hope by setting attainable goals to match their limitations, or acknowledging what they have achieved and finding hope in maintaining their current state. We have determined that the sources of hope are comprised of two categories: ［foundation and process of finding hope］ and ［specific goals and sources］. The former consists of: ［stylization dependent on experience］, ［method and will］, ［use of external information］, ［intrinsic foundation］, and ［extrinsic foundation］. The latter consists of: ［health］, ［source of joy and happiness］, ［family］, and ［social connections］