Search results for "PLASMA"

Surface structure determination by SEM image processing and electrochemical impedance of graphite+polyethylene composite electrodes

2004

Abstract The electrochemical impedance behaviour of heterogeneous or/and rough electrodes has usually been associated with some geometrical parameters of the surface structure or to a statistical description of the surface properties. An experimental method for sample preparation of graphite + polyethylene composite electrodes based on plasma etching is proposed. After plasma etching, the statistical properties of the electrode, such as the graphite particle size distribution and fractional coverage are measured from scanning electron microscopy pictures using image processing software. The statistical information obtained for the surface is combined with impedance equations of independent …

Plasma Functionalization of Multiwalled Carbon Nanotubes and Their Use in the Preparation of Nylon 6-Based Nanohybrids

2012

The possibility to obtain carbon nanotubes (CNT)/polyamide 6 composites with excellent mechanical properties in a simple, industrially scalable way is investigated. Commercial CNTs are treated by plasma while changing some key parameters (exposure time, plasma power, type of gas) in order to optimize the process and to achieve a sufficient degree of functionalization. The treated samples are characterized by Fourier transform infrared spectroscopy, Raman spectroscopy and X-ray photoelectron spectroscopy. The most interesting samples are selected to be used as reinforcing fillers, in different concentrations, in a polyamide 6 matrix. The mechanical tests show a dramatic increase of both tens…

Guillain-Barré Syndrome

2022

Background: Guillain–Barré syndrome is a rare disorder in which our body’s immune system attacks nerves determining weakness and tingling of extremities as first symptoms. It can also be associated to respiratory failure and require mechanical ventilation during hospitalization (up to 30% of patients). Nowadays patient’s hyper-reactive immune responses benefits from immunotherapies such as intravenous immunoglobulin (IVIg), therapeutic plasma exchange (TPE) and new biological drugs. Case Report: We report our experience with the case of a 64-year-old woman who presented a symmetric progressive flaccid paralysis after a week of mild cold symptoms. The respiratory and neurological symptoms wo…

Effect of spatial distribution of impurity ions on the signal of ‘C/O monitor for Wendelstein 7-X’ - an indicator of plasma wall interactions

2022

The ‘C/O monitor’ is a dedicated diagnostic system designed to monitor light impurities (B, C, N and O) in the Wendelstein 7-X (W7-X) stellarator. Its main goal is to provide fast (∼1 ms) information about the impurity level which is measured from a large plasma volume (high throughput). Its first subsystem dedicated to measure Lyman-α lines of H-like carbon (C5+ − 3.4 nm – used as PFC material) and oxygen (O7+ − 1.9 nm – common impurity absorbed by inner vessels’ walls) is going to be commissioned during the next Operational Phase of W7-X. Since the radiated photon intensity of a given impurity depends strongly on plasma kinetic parameters (Te, ne) and impurity transport, it is important t…

Mode-particle Interactions as Sources of Gamma-ray Bubbles in the Galaxy

A plasma outflow coming from the center of Our Galaxy is simulated by an ion beam reaching a nearly stationary magnetic field that can excite lower hybrid waves efficiently in the rarefied plasma (10-2-10-4 cm-3) surrounding the whole galaxy. The electrostatic lower hybrid waves are driven to instability via Cerenkov interaction. In this work we derive (by using a fluid model) the relevant dispersion relation and the expression for the growth rate by solving the dispersion relation both analytically and numerically. Parametric studies show that the growth rate of the instability increases with the beam density. The instability is found to have the maximum growth rate when the perpendicular …

Lecithin-cholesterol-acyltransferase deficiency: autosomal recessive transmission in a large kindred.

2008

Thirty-four members of a single Sardinian kindred with lecithin-cholesterol-acyltransferase deficiency have been studied. The kindred spans four generations and the parents of the two affected siblings are blood relatives. Segregation of the acyltransferase deficiency gene in the family clearly demonstrated an autosomal recessive mode of inheritance. Thirteen family members, including all obligate heterozygotes, had roughly half-normal acyltransferase activities (mean +/- S.D. = 0.39 +/- 0.06 mU/ml) when compared to 17 intrafamilial controls and spouses (mean +/- S.D. = 0.72 +/- 0.09 mU/ml) and 40 blood donors from Marburg/Lahn (mean +/- S.D. =0.76 +/- 0.1 mU/ml). Characterization of the he…

Lipoprotein profile and high-density lipoproteins: subfractions distribution in centenarians.

1998

In order to assess the role of HDL on longevity, we studied HDL subfraction distribution in centenarian women compared with a group of weight- and gender-matched healthy normolipidemic controls. We did not find any significant difference in the mean plasma lipid, apolipoprotein, and Lp(a) levels. On the contrary, in spite of similar HDL-cholesterol concentrations (1.32 ± 0.41 mmol/l in centenarians vs. 1.32 ± 0.25 mmol/l in controls, p = not significant), HDL<sub>2b</sub> and HDL<sub>3a</sub> levels were, respectively, significantly increased and significantly reduced in centenarians in comparison with controls (HDL<sub>2b</sub> 32.4 ± 9.2% in centenarian…

On the zopiclone enantioselective binding to human albumin and plasma proteins. An electrokinetic chromatography approach

2011

In this work, a methodology for the chiral separation of zopiclone (ZPC) by electrokinetic chromatography (EKC) using carboxymethylated-β-cyclodextrin as chiral selector has been developed and applied to the evaluation of the enantioselective binding of ZPC enantiomers to HSA and total plasma proteins. Two mathematical approaches were used to estimate protein binding (PB), affinity constants (K(1)) and enantioselectivity (ES) for both enantiomers of ZPC. Contradictory results in the literature, mainly related to plasma protein binding reported data, suggest that this is an unresolved matter and that more information is needed. Discrepancies and coincidences with previous data are highlighte…

RELATIONSHIPS OF SERUM URIC ACID WITH PLASMA RENIN ACTIVITY AND PLASMA ALDOSTERONE IN UNTREATED HYPERTENSIVE SUBJECTS

2013

In experimental studies conducted in rats, raising serum uric acid (SUA) levels resulted in stimulation of intrarenal renin expression. Studies in humans exploring the association of SUA with plasma renin activity (PRA) yielded conflicting results. Moreover, little is known about the relationship between plasma aldosterone concentration (PAC) and SUA. The aim of our study was to analyse the relationships between SUA, PRA and PAC and the influence of age and gender on these relationships in a group of subjects with primary hypertension. We enrolled 281 patients (men 59%), with untreated primary hypertension and normal renal function. The study population wad divided in two subgroups on the b…

FOKI AND BSMI VITAMIN D RECEPTOR GENE POLYMORPHISMS, PLASMA RENIN ACTIVITY AND ESSENTIAL ARTERIAL HYPERTENSION

2015

Objective: Our aims were to analyze the relationship between 25hydroxyvitamin D(25[OH]D) plasma levels and clinical and ambulatory blood pressure (BP) values, and to identify any possible association between hypertension and FokI and BsmI vitamin D receptor (VDR) gene polymorphisms in essential hypertensive patients. Design and method: Seventyone essential hypertensive patients and seventytwo controls, 18–75 years old, were enrolled. Clinical physical examination, routine blood chemistry, clinical BP, 24 hour ambulatory blood pressure monitoring, 25[OH]D and Plasma Renin Activity (PRA) assay, and FokI and BsmI VDR polymorphisms analysis were obtained. Results:We observed a significant negat…