A number of studies have indicated that plasmamembrane calcium ATPases (PMCAs) are expressed in the brain and spinal cord and could play important roles not only in the maintenance of cellular calcium...Full Text Available
In whole-cell recording, the conductance of the plasmamembrane of protoplasts isolated from mesophyll cells of leaves of oat (Avena sativa) was greater for inward than outward current....Full Text Available
Although the mechanism is unknown, Calculus Bovis and its active components, cholic acid analogs (CAAs), have been used in China to treat a wide range of diseases. Based on the previous finding that the potency of CAA is strongly dependent on the intrinsic surface activity, this paper aimed to investigate the role of the plasmamembrane in the pharmacological activity of CAAs. First, CAAs (0.1 mM) caused a surface activity-dependent depression on ATPase activity in the cell membrane extract, but it had no effects on other cellular extracts, suggesting an indispensable role of the membrane environment for pharmacological activity. Second, CAAs lowered the membrane fluidity of cultured Caco-2 cells with the same rank-order of potency sequence. Third, the hypothesis that any functional protein located on the membrane is influenced by changes in cellular ...
We showed recently that secretion of glutamate in biotin-limited cells of Corynebacterium glutamicum is mediated by carrier systems in the plasmamembrane (C. Hoischen and R. Krämer, Arch. Microbiol....Full Text Available
BackgroundWith the exception of vertebrates, most organisms have plasmamembrane associated ammonium transporters which primarily serve to import a source of nitrogen for nutritional...Full Text Available
Diverse cell polarity networks require positive feedback for locally amplifying distributions of signalling molecules at the plasmamembrane1. Additional...Full Text Available
Cellular actions of thyroid hormone may be initiated within the cell nucleus, at the plasmamembrane, in cytoplasm, and at the mitochondrion. Thyroid hormone nuclear receptors (TRs) mediate the biological...Full Text Available
Hyaluronan is a multifunctional glycosaminoglycan that forms the structural basis of the pericellular matrix. Hyaluronan is extruded directly through the plasmamembrane by one of three hyaluronan...Full Text Available
In the present study the authors have shown that glycoproteins are present in the plasmamembrane of Acanthamoeba castellanii by utilizing different radioactive labeling techniques. Plasmamembrane proteins in the amoeba were iodinated by "1"2"5I-lactoperoxidase labeling and the solubilized radiolabeled glycoproteins were separated by lectin-Sepharose affinity chromatography followed by polyacrylamide gel electrophoresis. The periodate/NaB"3H_4 and galactose oxidase/NaB"3H_4 labeling techniques were used for labeling of surface carbohydrates in the amoeba. Several surface-labeled glycoproteins were observed in addition to a diffusely labeled region with M_r of 55,000-75,000 seen on electrophoresis, which could represent glycolipids. The presence of glycoproteins in the plasmamembrane of Acanthamoeba castellanii was confirmed by metabolic labeling with ...
AMPA receptors (AMPARs) are critical for synaptic plasticity, and are subject to alterations based on subunit composition and receptor trafficking to and from the plasmamembrane. One of the...Full Text Available
The in situ assembly states of the glucose transport carrier protein in the plasmamembrane and in the intracellular (microsomal) storage pool of rat adipocytes were assessed by studying radiation-induced inactivation of the D-glucose-sensitive cytochalasin B binding activities. High energy radiation inactivated the glucose-sensitive cytochalasin B binding of each of these membrane preparations by reducing the total number of the binding sites without affecting the dissociation constant. The reduction in total number of binding sites was analyzed as a function of radiation dose based on target theory, from which a radiation-sensitive mass (target size) was calculated. When the plasmamembranes of insulin-treated adipocytes were used, a target size of approximately 58,000 daltons was obtained. For adipocyte microsomal membranes, we obtained target sizes of ...
Abstract in english The tegument surface of the adult schistosome, bounded by a normal plasmamembrane overlain by a secreted membranocalyx, holds the key to understanding how schistosomes evade host immune responses. Recent advances in mass spectrometry (MS), and the sequencing of the Schistosoma mansoni transcriptome/genome, have facilitated schistosome proteomics. We detached the tegument from the worm body and enriched its surface membranes by differential extraction, before subjecting t (more) he preparation to liquid chromatography-based proteomics to identify its constituents. The most exposed proteins on live worms were labelled with impearmeant biotinylation reagents, and we also developed methods to isolate the membranocalyx for analysis. We identified transporters for sugars, amino acids, inorganic ions and water, which confirm the importance of the tegument plasma ...
Excitation of low temperature helium or helium/water plasma and subsequent exposure to air of polyacrylonitrile (PAN) ultrafiltration membranes was used to hydrophilize the surface of these materials. We analyzed the effectiveness of this approach as a function of plasma operating variables including gas phase composition, plasma power, treatment time and system pressure. Following the changes in physical and chemical composition of the PAN surface resulting from these modifications was a major aspect of this work. Techniques such as the captive bubble contact angle method, ellipsometry, ESCA, and FTIR-ATR were all used. In addition, the formation and life-time of peroxides during these processes were determined. At low powers (<25W) and short treatment periods ({<=}30 sec), the main chemical conversion of PAN surfaces was simultaneous hydrophilization and stabilization via PAN cyclization. ...
Effects of physical environment on plasmamembrane semipermeability and osmotic induction of changes in aqueous cytoplasmic volume were studied in vegetative and spore cells of a plant pathogenic fungus,...Full Text Available
Cells of oat coleoptiles (Avena sativa L. cv. “Garry”) have been osmotically shocked in order to observe the effect of alterations of the plasmamembrane on some auxin...Full Text Available
The main function of white adipose tissue is to store nutrient energy in the form of triglycerides. The mechanism by which free fatty acids (FFA) move into and out of the adipocyte has not been resolved....Full Text Available
Sphingomyelin (SM) is an abundant phospholipid in cell membranes and in lipoproteins. In human plasma, SM is mainly found in atherogenic lipoproteins; therefore, higher levels of SM may promote atherogenesis....Full Text Available
An immunoglobulin Mk monoclonal (F8IVE9) antibody raised against oat (Avena sativa cv Garry) root homogenate has been produced and characterized. The predominant target...Full Text Available
In-vitro experiments using 203Pb were performed to identify the lead binding components in human peripheral blood. The distribution of lead in plasma, in the red cell membrane, and within the red cell...Full Text Available
Electrostatic nature of plant plasmamembrane (PM) plays significant roles in the ion uptake and toxicity. Electrical potential at the PM exterior surface (ψ0o) influences...Full Text Available
Current bioartificial extra-corporeal systems are bioreactors where cells are separated from the surrounding media by porous polymeric membranes. The present work focuses on the design of membranes that allow the differential diffusion of plasma metabolites and proteins such as immunoglobulin (IgG). This design will improve catabolites removal and reduce possible immune response and virus infection. We demonstrate the feasibility to synthesize the hydrogels confined to the macroporous structure of membranes by radiation-induced in situ polymerization. The hollow-fiber membranes were soaked in aqueous monomeric solution, rinsed and irradiated while submerged in oil. This procedure confined the hydrogel to the void internal volume of the pores of the membrane. Hydrogels of polyacrylamide and polyHEMA were synthesized this way by irradiation at 10 kGy. Hydraulic ...
Plasma is the component of blood from which lead is free to cross cell membranes and cause organ toxicity. Plasma lead levels, however, are extremely low and difficult to measure. Urinary lead originates...Full Text Available
Plasma nitriding was applied to improve the surface performance of titanium bipolar plate. XRD and SEM results showed a titanium nitride layer was formed after nitridation. In comparison with pure titanium, the interfacial contact resistance of plasma nitrided titanium was reduced to some extent by the nitridation treatment. However, high corrosion current was observed under electrochemical tests in 0.5 M H{sub 2}SO{sub 4} + 5 ppm HF. Both the electrical conductivity and corrosion resistance of the surface of plasma nitriding titanium did not reach the level of graphite. Some more improvements are expected in the plasma nitriding process or another surface modification on pure titanium. (author)
The PERMCAT is a membrane reactor proposed for processing fusion reactor plasma exhaust gas: tritium removal is obtained by isotopic swamping operating in counter-current mode. In this work, a membrane reactor using a permeator tube of length about 500 mm produced via diffusion welding of Pd-Ag thin foils is described. An appropriate mechanical design of the membrane module has been developed in order to avoid any significant compressive and bending stresses on the very long and thin wall permeator tube: two expanded bellows have been applied to the Pd-Ag tube, so that it has been pre-tensioned before operating. The elongation of the metal permeator under hydrogenation has been theoretically estimated and experimentally verified for properly designing the membrane reactor.
A dense and supersaturated nitrogen layer with higher conductivity is obtained on the surface of austenitic stainless steel 304L by the low temperature plasma nitriding. The effect of plasma nitriding on the corrosion behavior and interfacial contact resistance (ICR) for the austenitic stainless steel 304L was investigated in 0.05M H{sub 2}SO{sub 4}+2ppm F{sup -} simulating proton exchange membrane fuel cell (PEMFC) environment using electrochemical and electric resistance measurements. The experiment results show that the stable passive film is formed after the potentiostatic polarization at the specified anodic or cathodic potentials under PEMFC operation condition, and the plasma nitriding improves slightly the corrosion resistance and decreases markedly the ICR of 304L. The ICR of the plasma nitrided 304L increases after the potentiostatic polarizations for 4h, and lower than ...
Ultrathin solid polymer electrolyte membranes containing sulfonic ester groups were prepared by polymerization of methyl benzenesulfonate and octamethylcyclotetrasiloxane in a glow discharge plasma. The sulfonic ester groups of the plasma polymer were transformed to lithium sulfonate groups by treatment with lithium iodide. Hybridization of this plasma polymer containing the lithium sulfonate groups with poly(ethylene oxide) (average Mw 300) resulted in the formation of a single lithium ion conductive film. The hybrid polymer electrolyte films were about 1 #mu#m thick, pinhole-free, adherent to various substrates, and showed ionic conductivities at 60 degrees C of the order of 10"- "6 S cm"- "1 (10"2 #OMEGA# cm"2 resistance per unit area of as-prepared solid polymer electrolyte). This material shows promise for electrochemical applications such as all solid-state lithium batteries, sensors, and ...
In-vitro experiments using "2"0"3Pb were performed to identify the lead binding components in human peripheral blood. The distribution of lead in plasma, in the red cell membrane, and within the red cell was also investigated. Studies of the distribution of "2"0"3Pb in the whole blood showed that at a lead concentration of 2.45 #mu#mol/l (50 #mu#g/100 ml) about 94% of lead had been incorporated by the erythrocytes and 6% remained in the plasma. After extraction of lipid by a methanol/chloroform mixture, about 75% of the lead was found to be associated with the protein fraction. The lipid contained about 21% of the "2"0"3Pb, the remainder being in the aqueous plasma. SDS polyacrylamide gel electrophoresis of blood plasma showed that almost 90% of the "2"0"3Pb was present in the albumin fraction; the remainder was likely to be associated with high molecular weight globulins. Several ...
Incorporation of /sup 32/P from (gamma-32P)ATP into tyrosine residues of the insulin-like growth factor (IGF)-II receptor was observed in a Triton X-100-insoluble fraction of rat adipocyte plasmamembranes. IGF-II receptor phosphorylation proceeded to a stoichiometry of approximately 0.5 mol of phosphate/IGF-II binding site after 10 min of incubation at 4 degrees C. A Km for ATP of 6 microM was calculated for this phosphorylation reaction. Addition of IGF-II caused an approximately 2-fold increase in tyrosine phosphorylation of the IGF-II receptor in this preparation. In contrast, phosphorylation of angiotensin II by the Triton X-100 washed membranes was not stimulated by IGF-II. Incubation of purified receptor immobilized on IGF-II agarose or of receptor-enriched low density microsomal membranes with (gamma-32P)ATP did not result in appreciable incorporation of (/sup 32/P)phosphate into the IGF-II ...
PtdIns4P is the major precursor for the synthesis of the multifunctional plasmamembrane lipid, PtdIns(4,5)P2. Yet PtdIns4P also functions...Full Text Available
1-Naphthylphthalamic acid (NPA) is a specific inhibitor of polar auxin transport that blocks carrier-mediated auxin efflux from plant cells. To allow identification of the NPA receptor thought to be...Full Text Available
A single plasma process involving three consecutive steps has been developed for producing high gas flow catalytic nanostructures on the electrodes of proton exchange membrane (PEM) fuel cells (FC). Using a high density helicon radio frequency (13.56 MHz) plasma, nickel is sputtered onto a porous carbon support. Changing the background gas from argon to methane/hydrogen allowed 2 ?m long, 37 nm diameter carbon nanofibres (CNFs) to be grown by diffusion through the nickel clusters in a 'tip growth' mechanism at the relatively low temperature of 400 deg. C. The third step involves plasma sputtering of platinum onto the CNFs, resulting in nanoclusters (3-8 nm) being formed on the periphery of the CNFs. Four FC cathodes were synthesized on carbon paper and PTFE/carbon loaded cloth (known as gas diffusion layer, GDL), both with and without CNFs, with the Pt/CNFs nanostructures grown on PTFE/carbon loaded ...
a-Dystroglycan is an extracellular adhesion protein that is known to interact with different ligands. The interaction is thought to stabilize the integrity of the plasmamembrane. The N-terminal part of a-dystroglycan may be proteolytically processed to generate a small 38kDa protein (a-DG-N). The physiological significance of a-DG-N is unclear but has been suggested to be involved in nerve regeneration and myelination and to function as a potential biomarker for neurodegenerative and neuromuscular diseases. In this report we show that a-DG-N is released into different body fluids, such as lachrimal fluid, cerebrospinal fluid (CSF), urine and plasma. To investigate the significance of a-DG-N in CSF we examined the levels of a-DG-N and known neurodegenerative markers in CSF from patients di...
Radiation inactivation and sedimentation equilibrium analysis were used to determine the functional and physical size of the chicken hepatic membrane receptor that binds N-acetylglucosamine-terminated glycoproteins. Purified plasmamembranes from chicken liver were irradiated with high energy electrons and assayed for 125I-agalactoorosomucoid binding. Increasing the dose of ionizing radiation resulted in a monoexponential decay in binding activity due to a progressive loss of binding sites. The molecular mass of the chicken lectin, determined in situ by target analysis, was 69,000 +/- 9,000 Da. When the same irradiated membranes were solubilized in Brij 58 and assayed, the binding protein exhibited a target size of 62,000 +/- 4,000 Da; in Triton X-100, the functional size of the receptor was 85,000 +/- 10,000 Da. Sedimentation equilibrium measurements of the purified binding protein yielded a lower ...
The hypothesis that accumulation against sizable chemical gradients of free (non-phosphorylated) 2-deoxy-D-glucose (2dGlc) in isolated rat adipocytes results from an intracellular compartmentation of free hexose was investigated. Cells exposed to 20 ..mu..g/ml digitonin for 10' demonstrated an increased plasmamembrane permeability indexed by increased L-glucose entry rates and cellular (presumably cytosolic) protein and K/sup +/ loss. Functional integrity of intracellular organelles was indicated by the ability of the cells to support ATP-driven /sup 45/Ca/sup 2 +/-uptake. Equilibrium 3-O-methylglucose (3-O-MG, a non-accumulated hexose) levels were unaffected. These data suggest a specific permeabilizing action of digitonin at the plasmamembrane having no effect on intracellular organelles or passively distributed solutes. Upon addition of digitonin, free 2dGlc fell from 66.5 +/- 8.9 to 7.4 ...
Chromium electroplated AISI 316L stainless steel was nitrided using inductively coupled plasma (ICP) for application in the bipolar plate of a polymer electrolyte membrane fuel cell (PEMFC). A continuous and thin chromium nitride layer was formed at the surface of the samples after ICP nitriding for 2 h at 400 C. The interfacial contact resistance (ICR) and corrosion resistance in simulated PEMFC operating conditions were higher than the required values, while they varied with the applied dc bias voltage during the nitriding process. The ICR value decreased with an increase in bias voltage. Potentiodynamic polarization measurements showed that all of the nitrided samples had excellent corrosion resistance with a current density of {proportional_to}10{sup -7} A cm{sup -2} at the cathode. It was also found that the oxygen content at the surface was not increased after the corrosion test. X-ray diffractometry (XRD), field emission scanning ...
Extracellular ATP stimulates transmembrane ion fluxes in the mouse macrophage cell line J774. In the presence of Mg2+, nonhydrolyzable ATP analogs and other purine and pyrimidine nucleotides do not elicit this response, suggesting the presence of a specific receptor for ATP on the macrophage plasmamembrane. One candidate for such a receptor is the ecto-ATPase expressed on these cells. We, therefore, investigated the role of this enzyme in ATP-induced /sup 86/Rb+ efflux in J774 cells. The ecto-ATPase had a broad nucleotide specificity and did not hydrolyze extracellular ATP in the absence of divalent cations. /sup 86/Rb+ efflux was not blocked by inhibition of the ecto-ATPase and did not require Ca2+ or Mg2+. In fact, ATP-stimulated /sup 86/Rb+ efflux was inhibited by Mg2+ and correlated with the availability of ATP4- in the medium. In the absence of divalent cations, the slowly hydrolyzable ATP analogs adenosine 5'-(beta, ...
Reichert's membrane, an extraembryonic membrane present in developing rodents, has been proposed as an in vivo model for the study of basement membranes. We have used this membrane as a source for isolation...Full Text Available
Zeaxanthin is a carotenoid produced by plants and has been associated with protection of the photosynthetic machinery under light stress and, together with lutein, in protection of the central retina of the eye. Zeaxanthin levels in blood plasma have been negatively correlated to the development of AMD (age-related macular degeneration) (Gale et al., 2003). Under normal conditions, plants have a low content of zeaxanthin. The aim of this study was to increase the zeaxanthin content in green vegetables by post harvest treatments. Efficient conditions for activation of the endogenous enzyme system generating zeaxanthin was established and included incubation at low pH (2.5-5.5), with the membrane permeable acetic acid/acetate buffer at room temperature or above for 30min or more. Typically m...
The effects of orthovanadate on the uptake of sucrose by Ricinus cotyledons and on sucrose-coupled proton influx were measured in order to gain insight into the relationship to the plasmamembrane proton pump. Vanadate had no effect on short-term sucrose uptake. In long-term experiments (> 30 min) sucrose uptake was progressively inhibited, but only at high external sucrose concentrations. Vanadate did not affect proton efflux pumping in the absence of sucrose and neither did it change the initial rate of sucrose-coupled proton influx. However, it enhanced the maximal level of sucrose-induced alkalization of the medium at all sucrose concentrations tested. This is interpreted as an inhibiting effect of vanadate on the proton pump that recycles protons during sucrose-proton cotransport. The sensitivity towards vanadate indicates that this proton pump is an ATPase. A second proton-translocating system, that is insensitive to vanadate, is ...
Root growth is a highly dynamic process influenced by genetic background and environment. This paper reports the development of R scripts that enable root growth kinematic analysis that complements a new motion analysis tool: PlantVis. Root growth of Arabidopsis thaliana expressing a plasmamembrane targeted GFP (C24 and Columbia 35S:LTI6b-EGFP) was imaged using time-lapse confocal laser scanning microscopy. Displacement of individual pixels in the time-lapse sequences was estimated automatically by PlantVis, producing dense motion vector fields. R scripts were developed to extract kinematic growth parameters and report displacement to ?0.1 pixel. In contrast to other currently available tools, Plantvis-R delivered root velocity profiles without interpolation or averaging across the root s...
This study sought to quantitate lidocaine's interaction with alpha-1-acid glycoprotein (AAG), human serum albumin (HSA), and AAG in the presence of HSA, and to determine the extent of displacement of lidocaine from its binding site(s) by selected cardiovascular drugs (dipyridamole, disopyramide and quinidine). Since the limited experimental work reported in this area has involved the use of a single lidocaine concentration, this study involved the evaluation of a range of lidocaine concentrations. Lidocaine interaction with plasma proteins (AAG and HSA) was studied at 37/sup 0/C using an isothermal equilibrium dialysis system and /sup 14/C-lidocaine HCl. A dialysis membrane (M.W. cutoff 12,000 to 14,000) separated the two chambers of each dialysis cell. The extent of /sup 14/C-lidocaine dialysis was studied with respect to both drug and protein concentrations. Aliquots of each chamber of each of the cells were subjected to liquid ...
Clove (Caryophyllus aromaticus L.) has been used for clinical procedures. Blood constituents labeled with technetium-99m (99mTc) are used in nuclear medicine. The aim of this work was to evaluate the effects of clove extract on the labeling blood constituents with 99mTc and on the morphology of red blood cells. Blood samples were incubated with clove, stannous chloride and 99mTc. Plasma, blood cells, insoluble fractions of plasma and blood cells were separated. The radioactivity was counted and percentage of radioactivity (%ATI) to each blood fraction was calculated. The shape and morphometric parameter (perimeter/area ratio) were evaluated. Clove extract altered significantly (p<0.05) the %ATI of blood constituents and the shape of red blood cells without modifying the perimeter/area ratio. The results indicate that clove extract presents chemical compounds that interfere with the radiolabeling of blood constituents and alter the ...
Triphenylmethylphosphonium (TPMP+) partitions into the mitochondrial and cytosolic compartments in the rat white adipocyte in a potential-dependent fashion. The relationship between (/sup 3/H)TPMP+ distribution, intracellular cAMP generation and lipolysis in response to hormones and cAMP-mimetic compounds was examined. Half-maximal (/sup 3/H)TPMP+ efflux and glycerol release were produced by 15 and 9 nM adrenocorticotropin, 170 and 110 nM 1-epinephrine, 70 and 27 microM isobutylmethylxanthine and 800 and 750 microM dibutyryl cAMP, respectively. Hormone-stimulated cAMP generation was also correlated with (/sup 3/H)TPMP+ efflux and lipolysis in terms of concentration dependency. In kinetic experiments, glycerol release and (/sup 3/H)TPMP+ efflux in response to adrenocorticotropin or cholera toxin proceeded over a similar time course, whereas an earlier rise in cAMP generation was detected. The depolarizing effect of lipolytic compounds was localized to the mitochondrial compartment. When ...
Membrane protein structural biology is still a largely unconquered area, given that approximately 25% of all proteins are membrane proteins and yet less than 150 unique structures are available. Membrane...Full Text Available
Integration of solid-state biosensors and lipid bilayer membranes is important for membrane protein research and drug discovery. In these sensors, it is critical that the solid-state sensing...Full Text Available
In the course of designing a catalytic porous membrane reactor for experimental studies, both inside and outside of the non-reaction zones as well as the two ends of the membrane need to be completely sealed to ensure that there is no flow across the membrane in the non-reaction zone. Experiments show that up to 50% of the total flow across the membrane may be contributed by the axial flow along the wall of the non-reaction zones if only one side of the membrane is sealed. Another problem that cannot be solved by sealing is the capillary flow of the catalyst along the tube wall into the non-reaction zones when the catalyst is doped on the membrane. One of the best ways to avoid this axial flow of catalyst would be to use non-porous tubes in the non-reaction zones and join them with the porous membrane tube. In doing so, the cost of the ...
The history of the Czech Institute of Plasma Physics is highlighted. The article is structured as follows: Cyclic accelerators; Interaction of an external high-frequency field and high-temperature plasma - the tokamak; Interaction of an external high-frequency field and high-temperature plasma - pulse plasma systems; Low-temperature plasma - plasma technologies and new materials; Laser plasma - PALS; Optical diagnosis; and Teaching, conferences and international cooperation. (P.A.)
VACUTAINER PPT plasma preparation tubes were evaluated to determine the effects of various handling and shipping conditions on plasma human immunodeficiency virus (HIV) load determinations. Plasmas...Full Text Available
One of the design targets for the ITER Tokamak Exhaust Processing system is not to lose more than 10{sup -5} g h{sup -1} into the Normal Vent Detritiation System of the Tritium Plant. The plasma exhaust gas, therefore, needs to be processed in a way that an overall tritium removal efficiency of about 10{sup 8} is reached. Such a high decontamination factor can only be achieved by multistage processes. The third step of the three step CAPER process developed at the TLK is based on a so-called permeator catalyst (PERMCAT) reactor, a direct combination of a Pd/Ag permeation membrane and a catalyst bed. The PERMCAT principle is based on isotopic swamping in a counter current mode. Previous tritium experiments employing laboratory scale PERMCAT reactors have revealed decontamination factors as high as 10{sup 5} for the third CAPER step. First tritium tests with a technical scale PERMCAT reactor led to similar decontamination factors and clearly ...
One of the design targets for the ITER Tokamak Exhaust Processing system is not to lose more than 10"-"5 g h"-"1 into the Normal Vent Detritiation System of the Tritium Plant. The plasma exhaust gas, therefore, needs to be processed in a way that an overall tritium removal efficiency of about 10"8 is reached. Such a high decontamination factor can only be achieved by multistage processes. The third step of the three step CAPER process developed at the TLK is based on a so-called permeator catalyst (PERMCAT) reactor, a direct combination of a Pd/Ag permeation membrane and a catalyst bed. The PERMCAT principle is based on isotopic swamping in a counter current mode. Previous tritium experiments employing laboratory scale PERMCAT reactors have revealed decontamination factors as high as 10"5 for the third CAPER step. First tritium tests with a technical scale PERMCAT reactor led to similar decontamination factors and clearly demonstrated that the ...
The productivity of higher plants is, in part, dependent on transport of photosynthate from source to sink (in sugarcane, stalk) and upon its assimilation in cells of the sink tissue. In sugarcane, sucrose has been reported to undergo hydrolysis in the apoplast before uptake into the storage parenchyma, whereas recently, sucrose was reported to be taken up intact. This work was based on lack of randomization of ({sup 14}C)fructosyl sucrose accumulated after feeding tissue slices with this sugar. In this report, we present evidence from slices of stalk tissue that sucrose is taken up intact via a carrier-mediated, energy-dependent process. The evidence includes: (1) uptake of fluorosucrose, an analog of sucrose not subject to hydrolysis by invertase; (2) little or no randomization of ({sup 14}C) fructosyl sucrose taken up; (3) the presence of a saturable as well as a linear component of sucrose uptake; and (4) inhibition of both the saturable and linear components of sucrose uptake by ...
By improving the currently used lactoperoxidase method, we were able to obtain radioiodinated chicken luteinizing hormone (LH) that shows high specific binding and low nonspecific binding to a crude plasmamembrane fraction of testicular cells of the domestic fowl and the Japanese quail, and to the ovarian granulosa cells of the Japanese quail. The change we made from the original method consisted of (1) using chicken LH for radioiodination that was not only highly purified but also retained a high receptor binding potency; (2) controlling the level of incorporation of radioiodine into chicken LH molecules by employing a short reaction time and low temperature; and (3) fractionating radioiodinated chicken LH further by gel filtration using high-performance liquid chromatography. Specific radioactivity of the final {sup 125}I-labeled chicken LH preparation was 14 microCi/micrograms. When specific binding was 12-16%, nonspecific binding was as ...
Radixin is a cytoskeletal protein that may be important in linking actin to the plasmamembrane. Recent cloning of the murine and porcine radixin cDNAs revealed a protein highly homologous to ezrin and moesin. The authors have cloned and sequenced the human radixin cDNA and found the predicted amino acid sequence for the human protein to be nearly identical to those predicted for radixin in the two other species. By Southern analyses of Chinese hamster x human somatic cell hybrid DNA and of PCR products derived from hybrids, the coding gene (RDX) was mapped to 11q. Fluorescence chromosomal in situ hybridization with a cDNA plasmid further localized this gene to band 11q23. However, PCR amplification with [open quotes]radixin-specific[close quotes] primers on the hybrid DNA panel yielded an additional, very similar DNA sequence that was further characterized by direct sequencing of PCR products. This sequence represents a truncated version and ...
The endothelin-B (ETB) receptor is a G-protein-coupled receptor that binds endothelin ligands and is essential for the development of epidermal melanocytes and enteric neurons. Recent reports indicate that ETB is localized to nuclei in cardiac ventricular myocytes, although it has been thought that ETB is localized mainly on the plasmamembrane. It remains unknown, however, whether this unique distribution of ETB occurs in other tissues. To elucidate the subcellular distribution of ETB in the intestine, we performed immunofluorescence of ETB in mouse intestine using a specific antibody. ETB-like immunoreactivity was detected in both the mucosal and muscle layers. In the mucosal layer, villous epithelial cells, stromal cells of the lamina propria, and cryptic cells were immunostained. Subcellularly, ETB is localized mainly to the nuclei of villous epithelial cells. In the muscle layer, immunoreactivity of ETB was localized to the myenteric ...
Macrophage differentiation antigen associated with complement three receptor function (Mac-1) belongs to #beta#_2 subfamily of integrins that mediate important cell-cell and cell-extracellular matrix interactions. Biochemical studies have indicated that Mac-1 is a constitutive heterodimer in vitro. Here, we detected the heterodimerization of Mac-1 subunits in living cells by means of two fluorescence resonance energy transfer (FRET) techniques (fluorescence microscopy and fluorescence spectroscopy) and our results demonstrated that there is constitutive heterodimerization of the Mac-1 subunits and this constitutive heterodimerization of the Mac-1 subunits is cell-type independent. Through FRET imaging, we found that heterodimers of Mac-1 mainly localized in plasmamembrane, perinuclear, and Golgi area in living cells. Furthermore, through analysis of the estimated physical distances between cyan fluorescent protein (CFP) and yellow fluorescent ...
The aim of the present study was to test a mathematical model of the biochemical processes in the parathyroid glands responsible for the secretion of parathyroid hormone resulting from extracellular calcium reduction. A double exponential curve described the parathyroid hormone secretion induced by rapid lowering of blood-ionized calcium in humans with normal as well as abnormal parathyroid tissue. Our data show that it was possible to establish a simple mathematical model of the parathyroid hormone response to blood-ionized calcium lowering, sufficient to fit experimental data obtained from patients with abnormal and normal parathyroid tissue. The fitted parameters showed no significant differences between patients with insulin-dependent diabetes mellitus and controls. In primary hyperparathyroidism, the parathyroid hormone production and steady-state transport across the cell membrane were increased, probably due to the larger amount of parathyroid tissue in ...
This paper aims to study fundamentally the impacts of membrane properties on the reactive dye removal from dye/salt mixtures by nanofiltration membranes. To begin with, two types of nanofiltration membranes of similar pore size, namely asymmetric cellulose acetate membrane and thin-film composite polyamide membrane were fabricated, and their key physical, chemical and performance properties were characterized. After that, these resultant membranes were employed to perform dye removal experiments with aqueous solutions of reactive black 5 and NaCl under different operational parameters. The dye removal rate and steady permeate flux were determined and correlated with the measured membrane properties. It was found that there were significant differences between the dye removal performances o...
A sulfonated fluoroalkyl graft polymer (FGP) membrane was prepared as a polymer electrolyte. First, the FGP membrane was grafted with styrene under UV irradiation. The grafted FGP was then sulfonated to functionalize it for proton conductivity. The grafting degree of the membrane increased with increasing grafting time during UV irradiation. The proton conductivity of the membrane increased with increasing grafting degree. The swelling ratio was independent of the grafting time, however, the water uptake increased with increasing grafting degree. Based on these results, it was found that the UV-initiated styrene grafting occurred along the membrane thickness direction. Moreover, the membrane was embedded within the glass fibers of the composite. This composite electrolytic membrane had 1.15 times the proton conductivity of a Nafion 117 ...
Background: Protein disulfide isomerase (PDI) controls platelet integrin function, tissue-factor (TF) activation, and concentrates at fibrin and thrombus formation sites of vascular injury. Objective: We investigated involvement of surface thiol isomerases and especially PDI, in thrombin-mediated thrombin amplification on human platelets. Methods/Results: Using a new developed thrombin-dependent platelet thrombin generation assay we observed that the feedback activation of thrombin generation on the platelet surface does not depend on TF, as anti-TF antibodies inhibiting TF-induced thrombin formation in platelet-depleted plasma had no effect compared to vehicle-treated controls. Feedback activation of thrombin generation in the presence of platelets was significantly diminished by membrane impermeant thiol blockers or by the thiol isomerase-inhibitors bacitracin and anti-PDI antibody RL90, respectively. Platelet thrombin formation depends on ...
Although the intracellular ultrastructural processing of epidermal growth factor (EGF) and its receptor have been described in cell culture systems, very few studies have examined this phenomenon in intact tissues. We have examined the ultrastructural and biochemical handling of ["1"2"5I]EGF in the epidermis and hair follicle bulb of intact, viable, 3- to 5-day-old rat skin the EGF receptor distribution of which has already been documented and in which EGF has been shown to be biologically active. After incubation of explants with 10 nM ["1"2"5I]EGF for 2.5 h at 25 degrees or 37 degrees C, radiolabel was detected over the basal cells of the epidermis and hair follicle outer root sheath, confirming previous light microscope observations. More specifically, silver grains were observed near coated and uncoated plasmamembrane and coated membrane invaginations, Golgi apparatus, lysosomal structures, and nuclei. Sodium azide ...
Although the intracellular ultrastructural processing of epidermal growth factor (EGF) and its receptor have been described in cell culture systems, very few studies have examined this phenomenon in intact tissues. We have examined the ultrastructural and biochemical handling of (/sup 125/I)EGF in the epidermis and hair follicle bulb of intact, viable, 3- to 5-day-old rat skin the EGF receptor distribution of which has already been documented and in which EGF has been shown to be biologically active. After incubation of explants with 10 nM (/sup 125/I)EGF for 2.5 h at 25 degrees or 37 degrees C, radiolabel was detected over the basal cells of the epidermis and hair follicle outer root sheath, confirming previous light microscope observations. More specifically, silver grains were observed near coated and uncoated plasmamembrane and coated membrane invaginations, Golgi apparatus, lysosomal structures, and nuclei. Sodium ...
About 210 abstracts by Ukrainian and foreign authors submitted to the 11-th International Conference on Plasma Physics and Controlled Fusion and 2-nd Alushta International Workshop on the Role of Electric Fields in Plasma Confinement in Stellarators and Tokamaks have been considered by Conference Program Committee members. All the abstracts have been divided into 9 groups: Magnetic confinement systems (stellarators, tokamaks, alternative conceptions); plasma heating and current drive; ITER and fusion reactor aspects; basic plasma physics; space plasma; plasma dynamics and plasma-wall interaction; plasma electronics; low temperature plasma and plasma technologies; plasma diagnostics.
Recent results of experimental and theoretical investigations, carried out in the Institute of plasma Physics of the NSC KIPT, are presented in the report. The main problems of discussion are as follows: plasma confinement and heating in stellarators and electromagnetic traps; powerful quasi-steady-state plasma accelerators (QSPA); experiments relevant for ITER; fusion Plasma theory; methods of high temperature plasma diagnostics; plasma technology. The main prospects on the IPP investigators are discussed also.
In vitro the binding of polyribosomes to smooth endoplasmic-reticulum membranes is more sensitive to ionic strength than is the binding to rough endoplasmic-reticulum membranes. Polyribosomes...Full Text Available
Factors affecting the membrane filtration of food suspensions were studied for 58 foods and 13 membrane filters. Lot number within a brand, pore size (0.45 or 0.8 micrometer), and time elapsed before...Full Text Available
In the presence of electrochemical energy, several branched-chain neutral and acidic amino acids were found to accumulate in membrane vesicles of Bacillus stearothermophilus. The membrane vesicles contained...Full Text Available
The curvature elastic modulus (bending stiffness) of stearoyloleoyl phosphatidylcholine (SOPC) bilayer membrane is determined from membrane tether formation experiments. R. E. Waugh and R. M. Hochmuth...Full Text Available
Spontaneous rupture of membranes (ROM) is a normal component of labor and delivery. Premature ROM (PROM) refers to rupture of the fetal membranes prior to the onset of labor irrespective of gestational...Full Text Available
The biophysical properties of membrane phospholipids are controlled by the composition of their constituent fatty acids and are tightly regulated in Escherichia...Full Text Available
... Mirrors (Preprint) Ryan Conk et al. 15 September 2006 ... 4. TITLE AND SUBTITLE Stress Coatings for Large Scale Membrane Mirrors (Preprint) 5a. ...
A biodegradable polylactic acid (PLA)/poly(glycolide-co-lactide) copolymer (PLGA) membrane with polyglycolic acid (PGA) mesh was prepared to aid the effective regeneration of defective periodontal tissues. The microporous membrane used in this study consists of biodegradable polymers, and seems to have a structure to provide appropriate properties for periodontal tissue regeneration. Based on the albumin permeation test, it is known that the biodegradable membrane exhibits the suitable permeability of nutrients. The membrane maintained its physical integrity for 6-8 weeks, which could be sufficient to retain space in the periodontal pocket. Cell attachment and cytotoxicity tests were performed with respect to the evaluation of biocompatibility of the membrane. As a result, the membrane did not show any cytotoxicity. The safety and therapeutic efficacies of the ...
Proton exchange membrane (PEM) fuel cells are energy sources that have the ... for H2 /02 PEM fuel cells because their catalysts have properties suitable for 0 ...
Laser-induced phase-separation polymerization of a porous acrylate polymer is used for in-situ fabrication of dialysis membranes inside glass microchannels. A shaped 355 nm laser beam is used to produce a porous polymer membrane with a thickness of about 15 .mu.m, which bonds to the glass microchannel and forms a semi-permeable membrane. Differential permeation through a membrane formed with pentaerythritol triacrylate was observed and quantified by comparing the response of the membrane to fluorescein and fluorescently tagging 200 nm latex microspheres. Differential permeation was observed and quantified by comparing the response to rhodamine 560 and lactalbumin protein in a membrane formed with SPE-methylene bisacrylamide. The porous membranes illustrate the capability for the present technique to integrate sample cleanup into chip-based ...
AbstractWe propose a mechanism for the formation of membrane oscillations and traveling waves, which arise due to the coupling between the actin cytoskeleton and the calcium flux through...Full Text Available
Thin PTFE membranes were prepared by coating the PTFE dispersion onto the aluminum films. Thus the thin crosslinked PTFE (RX-PTFE) membranes were obtained by means of electron beam irradiation above the melting temperature of PTFE under oxygen-free atmosphere. The RX-PTFE membranes were pre-irradiated and grafted by styrene with or without divinylbenzene (DVB) in liquid phase. The existence of DVB accelerated the initial grafting rate. The styrene grafted RX-PTFE membranes are white colored, on the other hand, the styrene/DVB grafted RX-PTFE membranes are colorless. The proton exchange membranes (PEMs) were obtained by sulfonating the grafted membranes using chlorosulfonic acid. The ion exchange capacity (IEC) values of the PEMs ranging from 1.5 to 2.8 meq/g were obtained. The PEMs made from the styrene/DVB grafted ...
This report results from a contract tasking Eindhoven University of Technology as follows: The contractor will investigate the plasma treatment of surfaces and plasma enhanced deposition using EUT's cascade arc source as the basis for this effort.
The major activities of the various Institute's departments are highlighted. The following departments are included: (i) Tokamak; (ii) Pulse plasma systems; (iii) Thermal plasma; (iv) Materials engineering; (v) Laser plasma; and (vi) Optical diagnosis. (P.A.)
Results are described of a study and of the characteristics of sources of a non-equilibrium gas-discharge plasma. The plasma generators considered include glow, high frequency, and arc discharge generators. Thermodynamic, ionic, and electronic processes occurring in the plasmas are evaluated.
Dust particles in a plasma are charged negatively and are subject to various types of forces, including a drag force by plasma particles and a force due to the collective nature of a plasma. Dust particles are found in a sheath in laboratories balanced by the gravitational force and the electric force, while dust particles in space are ubiquitous, including planetary magnetospheres and interstellar space. Because of the novel nature of a complex system involving plasma particles and dust particles in a collective way, the dusty plasma is often called a complex plasma. The complex plasma is characterized by two distinctly different scales in time and in space. The plasma with electrons, ions and neutrals is characterized by the collective motion with a fast time scale and a short wavelength, while the dust particles move ...
Excitation of the HF electric field in the local plasma resonance region (LPRR) of inhomogeneous plasma by pumping electric field or modulated electron beam results to appearance of the ponderomotive force that presses plasma out of this region. Density cavity is formed in the LPRR due to this field. Further dynamics in this region depends on the plasma properties. For plasma with hot electrons ion-acoustic pulses run away from the cavity. at the local density maximum the new peak of electric field is excited. It results to the formation of new density cavity, etc. For isothermal plasma the density jump is formed.
The conductivity of the membrane is a limiting factor for the efficiency and power density of PEFCs. Because this conductivity is strongly dependent on the membrane hydration, water management is an important aspect of PEFC optimisation. Single cell model experiments were made in order to determine the in-plane hydration of a Nafion{sup R} membrane under fuel cell conditions as function of the gas humidities. (author) 4 fig., 3 refs.
A bioartificial kidney, which is composed of a membrane cartridge with renal epithelial cells, can substitute important kidney functions in patients with renal failure. A particular challenge is the maintenance of monolayer integrity and specialized renal epithelial cell functions ex vivo. We hypothesized that this can be improved by electro-spun, supramolecular polymer membranes which show clear benefits in ease of processability. We found that after 7?d, in comparison to conventional microporous membranes, renal tubular cells cultured on top of our fibrous supramolecular membranes formed polarized monolayers, which is prerequisite for a well-functioning bioartificial kidney. In future, these supramolecular membranes allow for incorporation of peptides that may increase cell function even further. PMID:20715132
Sulfonated poly(ether ether ketone) (SPEEK) membranes with various degrees of sulfonation (DS) have been prepared as a potential membrane material for proton exchange membrane by sulfonation process using mixtures of (15-30% concentration) fuming sulfuric acid and (95-98%) concentrated sulfuric acid as the sulfonating agent. The sulfonation process was conducted at room temperature by varying the acid ratio and reaction time. The produced membranes were then characterized by evaluating the ion exchange capacity (IEC), water uptake, thermal stability, proton conductivity and methanol permeability as a function of degree of sulfonation. The proton conductivity of the sulfonated PEEK membranes with various DS was within the magnitude of 10"-"3 and 10"-"2 S cm"-"1 at room temperature and the methanol permeability was in the range of 3.45 x 10"-"7 to 2.73 x 10"-"6 cm"2 s"-"1. The overall ...
During the past decades polymer membrane technology has been applied in various industries for a myriad of separation duties. They are also an important candidate for the solution of separation problems associated with the recovery of carbon dioxide in power plants. The application of membrane technology for carbon dioxide removal is discussed for two different ways of operation in present and future power plants. First, pressure driven operations are discussed, followed by a discussion of the use of membranes in absorbers. The pressure driven processes based on currently available gas separation membranes are shown to have poor separation characteristics. Further membrane development work appears to be necessary, especially in the area of temperature resistant membranes. Membrane selectivity goals are presented for present and future power ...
Equivalent circuit and electrical parameters for H-doped NH_4UO_2PO_4.3H_2O self supported membranes have been determined by impedance spectroscopy. The measurements were carried out with a dry membrane, at different temperatures, and a wet membrane in contact with different electrolyte solutions. Resistance values for the dry membrane decrease with temperature increase, which agrees with the weak protonic character of the H-doped ammonium uranylphosphate. On the other hand, differences in the electrical parameters, depending on the electrolyte considered were also obtained and are attributed to different conduction mechanisms. (Author).
Microporous membranes are suitable for the CO{sub 2}-MEA (monoethanolamine) system because the overall mass transfer coefficient K of the membrane is approximately 10 times larger than that of composite membranes consisting of microporous membranes and homogeneous membranes. The overall volumetric mass transfer coefficient K{center_dot} of the hollow-fiber contact is more than 5 times larger than that of a conventional packed bed, which suggests that adorption using the present method has the advantage of making the absorption more compact. 8 refs., 7 figs., 4 tabs.
Theoretical analysis of the electric field bifurcation is made for the LHD plasma. For given shapes of plasma profiles, a region of bifurcation is obtained in a space of the plasma parameters. In this region of plasma parameters, the electric field domain interface is predicted to appear in the plasma column. The reduction of turbulent transport is expected to occur in the vicinity of the interface, inducing a internal transport barrier. Within this simple model, the plasma with internal barriers is predicted to be realized for the parameters of T{sub e}(0) {approx} 2 keV and n(0) {approx_equal} 10{sup 18} m{sup -3}. (author)
PulsPlasma nitriding is now one of the established nitriding methods. This article describes PulsPlasma nitriding procedures and the boundary conditions necessary. The special features of PulsPlasma technology compared to DC plasma systems are illustrated. In addition, the process benefits of material treatment using a plasma are examined, as is system type. The article concludes with typical applications of PulsPlasma technology for treatment of stainless steel, cold-working steel, hot-working steel and sintered steel. (orig.)
The plasma cladding waveguide, which is a cylindrical dielectric core surrounded by a plasma cladding, is developed, and the guided modes and their characteristics of this waveguide are displayed through the present detailed theoretical research. The conditions of the single mode existing in the plasma cladding waveguide have been given, and the defined forbidden gap of frequency is discussed. It is found that the usage characteristics of the plasma cladding waveguide vary strongly with plasma frequency, and changing the plasma parameters can control the propagation mode. This paper focuses on exhibiting the basic characteristics and the potential applications of this new type of waveguide.
Experimentally it is shown that a movable grounded metallic plate placed inside a multi-dipole magnetic cage can vary the diffused plasma parameters such as density, plasma potential and electron temperature. Plasma is solely produced in the source section of a double plasma device by a dc hot filament discharge and a low-density plasma is produced in the target section by local ionization of neutral gas by the high energetic electrons coming from the source section. A grounded movable stainless steel plate is inserted in the target section of the device. The floating potential of the plate also changes depending on the position of the plate inside the magnetic cage.
Full text of publication follows: Energy and environment are two major concerns in our modern society due to the coming shortage in fossil energy sources and the growing of greenhouse gas emissions. The challenge for the coming years is to discover new energy resources and to develop devices that are compatible with a sustainable development and generate few (or zero) emission. One of these devices is the fuel cell feed by hydrogen, whose application fields are very large. In particular, the proton exchange membrane fuel cell (PEMFC) is the most realistic device for automotive application. However, hydrogen storage remains one of the most important challenges regarding its development. Although different techniques are available for storing hydrogen, no ideal solution has been found yet. Compression needs elaborated tanks in shape for supporting high pressures, liquefaction requires an expensive hydrogen cooling and adapted tanks. Chemical storage by hydrides ...
Full text of publication follows: Energy and environment are two major concerns in our modern society due to the coming shortage in fossil energy sources and the growing of greenhouse gas emissions. The challenge for the coming years is to discover new energy resources and to develop devices that are compatible with a sustainable development and generate few (or zero) emission. One of these devices is the fuel cell feed by hydrogen, whose application fields are very large. In particular, the proton exchange membrane fuel cell (PEMFC) is the most realistic device for automotive application. However, hydrogen storage remains one of the most important challenges regarding its development. Although different techniques are available for storing hydrogen, no ideal solution has been found yet. Compression needs elaborated tanks in shape for supporting high pressures, liquefaction requires an expensive hydrogen cooling and adapted tanks. Chemical storage by hydrides ...
Early effects of 100 Kilorads of X-rays on muscle cell membrane properties have been measured in sartorius muscles from Leptodactylus ocellatus. Threshold strength for rectangular current pulses increased 10% after irradiation, and action potential propagation velocity decreased 10%. Passive membrane parameters were calculated from potential responses to sub-threshold current pulses, assuming conventional cable theory. Specific membrane conductance increased to 18% after irradiation, membrane capacitance increased 14%, and length constant decreased 10% but membrane time constant was unchanged. Cell diameter decreased 5%, and resting membrane potential decreased 8%. Membrane parameters during an action potential were also evaluated by the phase-plane and current-voltage plot techniques. Irradiation significantly decreased the action potential ...
Amphiphilic block copolymers are synthesized by sulfonation of poly(styrene-b-methyl methacrylate) (PS-b-PMMA) using acetyl sulfate, and are blended with poly(vinylidene fluoride) (PVDF) to prepare a new proton exchange membrane, in which PMMA is miscible with PVDF. The morphology and the transport properties of the membranes are investigated as functions of the degree of sulfonation as well as the blend ratio. Notable transition of phase-separated morphology is observed as the PVDF content of the blend is increased. Both the proton conductivity and the ion-exchange capacity (IEC) of the membrane increase with increasing the degree of sulfonation of PS-b-PMMA, and they are also enhanced as the phase-separated domains of blend membrane are well-ordered. Unlike the Nafion membrane, the proton conductivity of the blend membrane increases up to 90 C, indicating the ...
Plasma nitriding of a Ti substrate is carried out under a low ambient pressure below 3kPa, and a plasma torch is prepared on a trial basis which is provided with a supersonic expansion nozzle considered to expand plasma jet optimally and to be effective for suppressing the occurrence of shock wave. The system used for the study is provided with a specimen holder having the function of adjusting the distance between the nozzle outlet and the substrate inside the vacuum chamber which is provided with a plasma torch in the flange member. The plasma torch is so structured that a supersonic expansion nozzle can be installed at the tip of the plasma torch. In this process wherein plasma jet is employed, hard nitrided layer can be formed by plasma irradiation for a short time even under such low pressure as less than 3kPa by ...
Experiments of plasma nitriding of titanium are carried out by two plasma sources. One is a microwave discharge plasma source under several Torr, and the other is a nitrogen arc jet generated under atmospheric pressure followed by rapid expansion into a gas wind tunnel. The relationship between the surface density of nitrogen atoms in the #alpha#-Ti and various plasma parameters is systematically studied. For the microwave nitrogen plasma, it is found that the effect of the vibration temperature is the most essential for the surface nitriding, whereas the effect of electron temperature, density and rotation temperature is less remarkable. It is also found that the higher vibration temperature of the microwave discharge nitrogen plasma makes the target temperature higher, and consequently, the surface density of atomic nitrogen remarkably increased. However, the ...
The most important results of theoretical and experimental studies of plasmas, which have been achieved at the IPJ in Swierk and IPPLM in Warsaw recently, are presented. Studies of physical phenomena in PF discharges, development of diagnostic techniques and research on new plasma technologies, as performed at IPJ, have been summarized. Studies of dense magnetized plasmas, investigation of physics and applications of laser-produced plasmas; and research on the development of advanced diagnostic techniques for the EUROATOM fusion program, as performed at IPPLM, are also described.
Gas separation membranes with polydimethylsiloxane(PDMS)/polystyrene(PS) were prepared by using the sequential interpenetrating polymer network (IPN) method with various PS contents (10?70wt%). These gas separation membranes can be applied to reduce the smoke density in the emission gas of diesel engines. PS content has a pronounced effect on the membrane performance. It was found that the optimized PS contents in the final membrane were 50wt%. The emission capacities of diesel engines used in this study were 632 cc and 11,149 cc. When the oxygen separation membrane was used in the diesel engines, the smoke density of both diesel engines was remarkably reduced (35?73%). The oxygen concentration in the inlet air affects the composition of the emission gases. Especially, hydrocarbon (HC) dec...
Research was performed to assess the feasibility of barrier membrane substances, for use within mining or associated high risk environments, in restricting the diffusion transport of radon gas quantities. Specific tests were conducted to determine permeability parameters of a variety of membrane materials with reference to radon flow capabilities. Tests were conducted both within laboratory and in-situ emanation environments where concentrations and diffusion flows of radon gas were known to exist. Equilibrium radon gas concentrations were monitored in initially radon-free chambers adjacent to gas sources, but separated by specified membrane substances. Membrane barrier effectiveness was demonstrated to result in reduced emanation concentrations of radon gas within the sampling chamber atmosphere. Minimum gas concentrations were evidenced where the barrier membrane material was ...
The murine 3T3-L1 fibroblast under appropriate incubation conditions differentiates into an adipocyte phenotype. This 3T3-L1 adipocyte exhibits many of the morphologic, biochemical, and insulin-responsive features of the normal rodent adipocyte. Using quantitative electron microscopic (EM) autoradiography we find that, when /sup 125/I-insulin is incubated with 3T3-L1 adipocytes, the ligand at early times of incubation localizes to the plasmamembrane of the cell preferentially to microvilli and coated pits. When the incubation is continued at 37 degrees C, /sup 125/I-insulin is internalized by the cells and preferential binding to the villous surface is lost. With the internalization of the ligand, two intracellular structures become labeled, as determined by the method of hypothetical grain analysis. These include large clear, presumably endocytotic, vesicles and multivesicular bodies. Over the first hour of incubation the labeling of these ...
Prostaglandin E2 (PGE2) has been shown to increase the synthesis of hyaluronic acid in cultured fibroblasts by increasing the activity of hyaluronate synthetase, a group of plasmamembrane-bound synthetic enzymes. We examined whether PGE2 also increased the activity of those enzyme systems involved in the synthesis of sulfated glycosaminoglycan in the human embryonic lung fibroblast. Exposure of cells to PGE2 resulted in dose-dependent increases in glucosamine incorporation into all sulfated glycosaminoglycan subtypes. PGE2 at 10(-7) mol/L increased total glycosaminoglycan per dish to 21.6 +/- 3.1 micrograms versus 12.0 +/- 2.5 micrograms in control untreated cultures. Stimulation of endogenous PGE2 production by bradykinin had a similar effect on glycosaminoglycan synthesis. To examine whether PGE2 affected sulfated glycosaminoglycan protein core production, cells were labeled with tritiated glucosamine in the presence of cycloheximide. Under ...
In situ assembly states of rat adipocyte glucose transport protein in plasmamembrane (PM) and in microsomal pool (MM) were assessed by measuring target size (TS) of D glucose-sensitive, cytochalasin B binding activity. High energy radiation inactivated the binding in both PM and MM by reducing the total capacity of the binding (B/sub T/) without affecting the dissociation constant (K/sub D/). The reduction in B/sub T/ as a function of radiation dose was analyzed based on classical target theory, from which TS was calculated. TS in the PM of insulin-treated adipocytes was 58 KDa. TS in the MM of noninsulin-treated and insulin-treated adipocytes were 112 and 109 KDa, respectively. With MM, however, inactivation data showed anomalously low radiation sensitivities at low radiation doses showing a shoulder in the semilog plots, which may be due to an interaction with a radiation sensitive inhibitor. With these results, they propose the following ...
Insect host/parasitoid interactions are co-evolved systems in which host defenses are balanced by parasitoid mechanisms to disable or hide from host immune effectors. Although there is a rich literature on these systems, parasitoid immune-disabling mechanisms have not been fully elucidated. Here we report on a newly discovered immune-disabling mechanism in the Pieris rapae/Pteromalus puparum host/parasitoid system. Because venom injections and parasitization suppresses host phagocytosis, we turned attention to the P. rapae scavenger receptor (Pr-SR), posing the hypothesis that P. puparum venom suppresses expression of the host Pr-SR gene. To test our hypothesis, we cloned a full-length cDNA of the Pr-SR. Multiple sequences alignment showed the deduced amino acid sequence of Pr-SR is similar to scavenger receptors of other lepidopterans. Bacterial and bead injections induced Pr-SR mRNA and protein expression, which peaked at 4h post-bead injection. Venom injection inhibited Pr-SR ...
Laron syndrome (LS) is an autosomal recessively inherited condition characterized by insensitivity to endogenous and exogenous GH. Affected individuals have severe episodes and other characteristic features. GH receptor gene mutations are present in all affected individuals in whom molecular studies have been reported. The GH receptor is a plasmamembrane-spanning protein in which the extracellular domain binds circulating GH and the intracellular domain interacts with the JAK-2 kinase and possibly other intracellular signaling molecules. GH receptor dimerization occurs on GH binding and is thought to be required for normal signal transduction. We have studied the GH receptor genes of four unrelated individuals affected with LS from the United States, Italy, Saudi Arabia, and India. We have identified four different missense mutations that alter consecutive amino acids 152 to 155 in or near the dimerization domain of the GH receptor. One of ...
Asialoorosomucoid (ASOR) is internalized and degraded by HepG2 cells after binding to the asialoglycoprotein (ASGP) receptor, internalization through the coated pit/coated vesicle pathway, and trafficking to lysosomes. Primaquine, an 8-aminoquinoline antimalarial compound, inhibits ASOR degradation at concentrations greater than 0.2 mM by neutralizing intracellular acid compartments. This leads to alterations in surface receptor number, receptor-ligand dissociation, and receptor recycling. We have investigated the effects of primaquine on 125I-ASOR uptake and degradation as a function of primaquine concentration and duration of exposure. Concentrations below those required for neutralization of acidic compartments block 125I-ASOR degradation in HepG2 cells and lead to intracellular ligand accumulation. This effect is maximal at 80 microM primaquine. The intracellular 125I-ASOR is undegraded, dissociated from the ASGP receptor, and contained within vesicular compartments distinct from ...
Asialoorosomucoid (ASOR) is internalized and degraded by HepG2 cells after binding to the asialoglycoprotein (ASGP) receptor, internalization through the coated pit/coated vesicle pathway, and trafficking to lysosomes. Primaquine, an 8-aminoquinoline antimalarial compound, inhibits ASOR degradation at concentrations greater than 0.2 mM by neutralizing intracellular acid compartments. This leads to alterations in surface receptor number, receptor-ligand dissociation, and receptor recycling. We have investigated the effects of primaquine on 125I-ASOR uptake and degradation as a function of primaquine concentration and duration of exposure. Concentrations below those required for neutralization of acidic compartments block 125I-ASOR degradation in HepG2 cells and lead to intracellular ligand accumulation. This effect is maximal at 80 microM primaquine. The intracellular 125I-ASOR is undegraded, dissociated from the ASGP receptor, and contained within vesicular compartments distinct from ...
Radio frequency (RF) plasma nitriding using different input plasma processing powers (250-600 W) improves the surface of titanium by forming hard phases of TiN, Ti{sub 2}N, and Ti (N) into the surface. The characteristics of the compound layer have been investigated by optical microscopy, microhardness measurements, and X-ray diffraction. The effect of plasma power on the sample temperature, electron temperature, and plasma density was studied using Langmuir double probe. The measured surface hardness value of the compound layer is 2190 HV 0.1 for treated sample at plasma power 500 W. The compound thickness continuously increases as the plasma power increases. The highest nitriding rate of 5.88 {mu}m{sup 2}/s was recorded when the input plasma power was adjusted at 550 W. This high nitriding rate of treated titanium samples is ascribed to ...
Radio frequency (RF) plasma nitriding using different input plasma processing powers (250-600 W) improves the surface of titanium by forming hard phases of TiN, Ti_2N, and Ti (N) into the surface. The characteristics of the compound layer have been investigated by optical microscopy, microhardness measurements, and X-ray diffraction. The effect of plasma power on the sample temperature, electron temperature, and plasma density was studied using Langmuir double probe. The measured surface hardness value of the compound layer is 2190 HV 0.1 for treated sample at plasma power 500 W. The compound thickness continuously increases as the plasma power increases. The highest nitriding rate of 5.88 #mu#m"2/s was recorded when the input plasma power was adjusted at 550 W. This high nitriding rate of treated titanium samples is ascribed to the high ...
The plasma protein binding of phenytoin was investigated in 100 epileptic patients, using equilibrium dialysis at 37 degrees C. The unbound fractions of phenytoin in plasma formed a skewed distribution,...Full Text Available
Plasma nitriding as a diffusion process is the oldest plasma-assisted process for the surface treatment of metals. Although the use of this process in industry is already well developed and established there are still several scientific questions in the basic understanding of the process and consequently some problems and limits concerning its upscaling for industrial use. Therefore it is necessary to get reproducible results for different geometries of workpieces and for different workload sizes. Correlations between different plasma and treatment parameters, especially in big plants, have to be considered. To understand the process handling using some simple but impressive models the difficulties of treating single parts or mixed workloads are explained. For profitable applications of plasma nitriding plants, some guidelines for the use and selection of a suitable process and a device are given. By ...
A new miniature high-frequency (HF) plasma source intended for bio-medical applications is studied using nitrogen/oxygen mixture at atmospheric pressure. This plasma source can be used as an element of a plasma source array for applications in dermatology and surgery. Nitric oxide and ozone which are produced in this plasma source are well-known agents for proliferation of the cells, inhalation therapy for newborn infants, disinfection of wounds and blood ozonation. Using optical emission spectroscopy, microphotography and numerical simulation, the gas temperature in the active plasma region and plasma parameters (electron density and electron distribution function) are determined for varied nitrogen/oxygen flows. The influence of the gas flows on the plasma conditions is studied. Ozone and nitric oxide concentrations in the effluent of the ...
Fasting plasma concentrations of magnesium were measured by neutron activation analysis in 30 non-diabetics and 87 diabetics (55 non-insulin-treated, 32 insulin treated). Plasma concentrations of magnesium...Full Text Available
Prof. Kodi Husimi was the director of the Institute of Plasma Physics of Nagoya University during 12 years from the beginning of the institute establishment in 1961. His main contribution on promotion of plasma physics and fusion research at the Institute is summarized. (author)
1 The plasma protein binding of theophylline was determined after addition of [14C]-theophylline (15 micrograms/ml) to plasma from 24 healthy drug-free volunteers and equilibrium dialysis for 2 h at...Full Text Available
High power and particle deposition on target materials are encountered in many applications including magnetic and inertial fusion devices, nuclear and high energy physics applications, and laser and discharge produced plasma devices. Surface and structural damage to plasma-facing components due to the frequent loss of plasma confinement remains a serious problem for the Tokamak reactor concept. The deposited plasma energy causes significant surface erosion, possible structural failure, and frequent plasma contamination.
The bibliography contains citations concerning plasma immersion ion implantation (PIII) and equipment. PIII is a new technique to implant plasma ions into materials for surface modification and treatment. Topics include plasma nitriding, semiconductor doping, ion energy distribution, ion dose, pulsed plasma, metal plasma, and defect passivation. References also review applications in semiconductor device and integrated circuit manufacture, silicon material fabrication, aerospace bearings, carbon coatings on metals, and ceramic coatings. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)
In the present paper we propose a model of physical phenomena behind the front face of the electrodes in an impulse plasma accelerator. The model is based on the results of recent experimental observations and measurements. It correlates plasma dynamics with mechanism of phenomena in a column of pinching plasma. On the contrary to the previous model the current one suggests the series of relatively short pulses of metallic ions from the erosion of electrode material. Till now the pinch was treated rather as a nearly continuous source of metallic plasma, feeding the process with ions from the erosion of electrode material. (author)
We studied the optimum plasma conditions that are required for efficient high-order harmonic generation in platinum plume. Harmonics up to the 49th order (?=16.32 nm) are analyzed under various conditions of laser-plasma interaction. Time-resolved ultraviolet spectra of platinum plasma at both optimum and nonoptimum conditions of harmonic generation are presented. We calculated the ionization states of the plasma, free electron density, and singly charged ion density at different prepulse intensities and compared them with experimental results.
The influence of motion of ions and electron temperature on nonlinear one-dimensional plasma waves with velocity close to the speed of light in vacuum investigated. It is shown that although the wavebreaking field weakly depends on mass of ions, the nonlinear relativistic wavelength essentially changes. The nonlinearity leads to the increase of the strong plasma wavelength, while the motion of ions leads to the decrease of the wavelength. Both hydrodynamic approach and kinetic one, based on Vlasov-Poisson equations, are used to investigate the relativistic strong plasma waves in a warm plasma. The existence of relativistic solitons in a thermal plasma is predicted.
In terms of the kinetic theory of the interaction between the high-power short-time laser pulses with plasma based on the propagator plotting for the plasma particle distribution functions one studied the generation of the hot electrons and of the fast ions as the relativistic femtosecond laser pulses travelled through the supercritical density plasma. One performed calculations based on the various values of the laser pulse intensity, types of the multiple-charged ions, the plasma inhomogeneity degree. One studied the acceleration mechanisms both of the plasma electrons and ions
The paper presents experimental investigations of main features of plasma surface interaction and energy transfer to the material surface in dependence on plasma heat loads. The experiments were performed with QSPA repetitive plasma pulses of the duration of 0.25 ms and the energy density up to 2.5 MJ/m2. Surface morphology of the targets exposed to QSPA plasma screams is analyzed. Relative contribution of the Lorentz force and plasma pressure gradient to the resulting surface profile is discussed. development of cracking on the tungsten surface and swelling of the surface are found to be in strong dependence on initial temperature of the target.
This study was designed to evaluate the suitability of a novel bioabsorbable material in treating bone defects. A poly(desaminotyrosyl-tyrosine-ethyl ester carbonate) (PDTE carbonate) membrane (thickness...Full Text Available
The canonical Wnt/β-catenin pathway plays a pivotal role in regulating embryogenesis and tumorigenesis by promoting cell proliferation. BAMBI (BMP and activin membrane-bound inhibitor) has...Full Text Available
SYNOPSISRhomboid proteases are a fascinating class of enzymes that combine a serine protease active site within the core of an integral membrane protein. Despite having key roles...Full Text Available
Amino acid transport in membrane vesicles of Bacillus stearothermophilus was studied. A relatively high concentration of sodium ions is needed for uptake of L-alanine (Kt = 1.0 mM) and L-leucine (Kt...Full Text Available
Electrospinning, a flexible jet-based fiber, scaffold, and membrane fabrication approach, has been elucidated as having significance to the heath sciences. Its capabilities have been most impressive...Full Text Available
Tubular membrane structures are widespread in eukaryotic cells, but the mechanisms underlying their formation and stability are not well understood. Previous work has focused on tube extrusion from...Full Text Available
The localization of gold in the synovial membrane of rheumatoid arthritis patients treated with sodium aurothiomalate was examined and quantitative analysis of epon-embedded sections was carried out...Full Text Available
Membranous dysmenorrhea is an unusual clinical entity. It is characterized by the expulsion of huge fragments of endometrium during the menses, favored by hormonal abnormality or drug intake. This report describes a case with clinical, US, and MRI findings before the expulsion. Differential diagnoses are discussed. (orig.)
IntroductionThe murine air pouch is a bursa-like space that resembles the human synovial membrane. Injection of monosodium urate (MSU) crystals into the pouch elicits an acute inflammatory...Full Text Available
Cell membranes are studded with protrusions that were thoroughly analyzed with electron microscopy. However, the nanometer-scale three-dimensional motions generated by cell membranes to fit the topography of foreign surfaces and initiate adhesion remain poorly understood. Here, we describe the dynamics of surface deformations displayed by monocytic cells bumping against fibronectin-coated surfaces. We observed membrane undulations with typically 5 nm amplitude and 5-10 second lifetime. Cell membranes behaved as independent units of micrometer size. Cells detected the presence of foreign surfaces at 50 nm separation, resulting in time-dependent amplification of membrane undulations. Molecular contact then ensued with apparent cell-membrane separation of 30-40 nm, and this distance steadily decreased during the following tens of seconds. Contact maturation was ...
Membrane cofactor protein (MCP or gp45-70) of the complement system is a cofactor for factor I-mediated cleavage of fluid-phase C3b and C3b-like C3, which opens the thioester bond. In the present study...Full Text Available
The binding of amphiphilic molecules to lipid bilayers is followed by 19F NMR using chemical shift and line shape differences between the solution and membrane-tethered states of...Full Text Available
In this observational study, we compared erythrocyte membrane fatty acids in infants consuming formula supplemented with docosahexaenoic acid (DHA) and arachidonic acid (ARA) with those consuming...Full Text Available
Objective: To evaluate effects of epigallocatechin-3-gallate (EGCG) on the viability, membrane properties, and zinc distribution, with and without the presence of Zn2+, in human prostate...Full Text Available
Naturally occurring and contaminant ferromagnetic and ferrimagnetic particles have been found within or near cells, and might allow pulsed magnetic fields to create transient cell membrane opening ("pores")....Full Text Available
Measurement of intrathylakoid aqueous volumes by electron spin resonance spectroscopy was used to study ionic permeability properties of thylakoid membranes isolated from Beta vulgaris...Full Text Available
The effect of blood lead on erythrocyte membrane proteins was studied in 28 workers from a scrap lead refining factory and in 18 controls working in railway construction. Sodium dodecyl sulphate-polyacrylamide...Full Text Available
Electron spin resonance (ESR) studies have been performed on spin-labeled model membranes aligned using the isopotential spin-dry ultracentrifugation (ISDU) method of Clark and Rothschild. This method...Full Text Available
SpoIIIE is an FtsK-related protein that transports the forespore chromosome across the Bacillus subtilis sporulation septum. We use membrane photobleaching and protoplast assays to...Full Text Available
Transitions at 28-32°C in membranes of many kinds of seeds influence their germination and subsequent growth. Changes at 28-32°C in the rates of loss of endogenous amino acids from imbibed...Full Text Available
Amino acid transport was studied in membrane vesicles of the thermophilic anaerobic bacterium Clostridium fervidus. Neutral, acidic, and basic as well as aromatic amino acids were transported at 40...Full Text Available
The molecular diversity of the gene encoding the outer membrane protein A (OmpA) of Haemophilus parasuis has been unclear. In this study, the structural characteristics, sequence types,...Full Text Available
The flux ratio (influx/efflux) of K+ across the plasmalemma of beet cells at an external potassium concentration of 0.6 mm does not respond to changes of membrane potential in the...Full Text Available
Alterations in basement membrane components, notably proteoglycans, in a rat model of polycystic kidney disease have been investigated. Rats were fed phenol II (2-amino-4-hydroxyphenyl-5-phenyl thiazole)...Full Text Available
Biological membranes are lamellar structures composed of two leaflets capable of supporting different mechanical stresses. Stress differences between leaflets were generated during micromechanical experiments...Full Text Available
A new method of random data analysis has been developed with special implications for membrane noise. The integral spectrometer uses overlapping broad-band filters of simple design, whose bandwidth...Full Text Available
It is known that a high-power laser propagating through an underdense plasma can acquire a minimum spot size due to relativistic self-focusing. Beyond the focus, the nonlinear refraction starts weakening, and the spot size of the laser increases, showing periodic self-focusing/ defocusing behavior with the distance of propagation. To overcome the defocusing, we propose the introduction of a localized upward plasma density ramp. In the presence of an upward ramp of plasma density, the laser beam obtains a minimum spot size and maintains it with only a mild ripple. For suitable parameters of the laser and the plasma, we have deduced conditions for the self-focusing. This kind of plasma density ramp may be observed in a gas-jet plasma experiment and resembles a plasma lens.
It is shown that plasma viscosity does not influence the magnetic island rotation directly. Nevertheless, it leads to nonstationarity of the plasma velocity. This nonstationarity is the reason of the viscosity effect on island rotation. (author)
A nonneutral /sup 7/Li/sup +/ ion plasma is described in which ion Langmuir waves are observed for the first time. The properties of these waves near the Brillouin density limit are investigated.
Much theoretical and experimental efforts have been expended in recent years to study those atomic processes which are specially relevant to understanding high temperature laboratory plasmas. For magnetically confined fusion plasmas, the temperature range of interest spans from the hundreds of eV at plasma edges to 10 keV at the center of the plasma, where most of the impurity ions are nearly fully ionized. These highly stripped ions interact strongly with electrons in the plasma, leading to further excitation and ionization of the ions, as well as electron capture. Radiations are emitted during these processes, which easily escape to plasma container walls, thus cooling the plasma. One of the dominant modes of radiation emission has been identified with dielectronic recombination. This paper reviews this work.
The data set consists of the following: - Biochemical analysis of Deschampsia leaves and root; - Chromatographic Analysis of membrane lipids (lipid profile) ...
This dissertation deals with membrane gas absorption in the application of CO{sub 2} removal by aqueous alkanolamines, using microporous PTFE hollow fiber membranes. A new lab-scale apparatus was constructed and an extensive experimental study executed to determine the performance of the membrane gas absorber, with aqueous solutions of monoethanolamine (MEA) and methyldiethanolamine (MDEA) as absorbents. The important operation parameters CO{sub 2} partial pressure, gas velocity, liquid velocity, temperature and liquid CO{sub 2} loading were systematically varied within the range typically experienced in a process for exhaust gas CO{sub 2}-removal
Basement membranes contain several proteoglycans, and those bearing heparan sulfate glycosaminoglycans such as perlecan and agrin usually predominate. Most mammalian basement membranes also contain...Full Text Available
The diffusion of alkali vapours in the anode compartment of a DIR-MCFC produces the deactivation of the internal reforming catalyst. Sets of ceramic porous membranes purposed to limit the diffusion have been manufactured by different techniques and the influence of the preparation technique and of the preparative variables on the morphological characteristics of the membranes structures has been studied.
Since several years we apply the radiation-grafting technique to prepare polymeric membranes for application in polymer electrolyte fuel cells (PEFCs). Our investigations presented here focus on changes in toughness of these materials after the various synthesis steps and the importance of membrane toughness for their application in PEFCs. (author) 2 figs., 4 refs.
This document provides stakeholder evaluations on innovative technologies to be used in the remediation of volatile organic compounds from soils and ground water. The technologies evaluated are; in-well vapor stripping, in-situ bioremediation, and gas membrane separation.
This report is a brief review of biological and medical applications of ion-track membranes. The review aims at informing nuclear physicists about alternative (i.e. non-fundamental-science) use of heavy ion accelerators such as production of micro- and nano-porous materials. The ion-track membranes produced this way are employed in life sciences and numerous technological applications. The author focuses on recent results from the Flerov laboratory in co-operation with other scientific institutions and industrial partners.
Water transport in the ionomeric membrane, typically Nafion{reg_sign}, has profound influence on the performance of the polymer electrolyte fuel cell, in terms of internal resistance and overall water balance. In this work, high resolution neutron imaging of the Nafion{reg_sign} membrane is presented in order to measure water content and through-plane gradients in situ under disparate temperature and humidification conditions.
The DITE (Divertor Injection Tokamak Experiment) program has been undertaken to demonstrate the feasibility of impurity control by the use of a diverter in an injection-heated toroidal plasma configuration. Rather than behaving in accordance with neoclassical toroidal containment theory, the plasma is subject to various instabilities, particularly the resistive fluid MHD types, follows the empirical scaling of energy confinement time with plasma parameters observed in other plasma devices. DITE experiments have, however, extended the range of current and density. Impurities arising from plasma interactions with the vacuum vessel surface are controlled by the bundle divertor, which diverts a portion of plasma and power in the plasma scrape-off layer into a separate target chamber where impurities can be removed. Auxiliary ...
The properties of polycrystalline (Ti, Al)N coatings deposited on non-nitrided, classically plasma-nitrided and low pressure plasma-nitrided AISI H11 steel samples were investigated. The plasma deposition and low pressure plasma nitriding were performed in a Z700-LH magnetron sputter ion plating unit, while a separate unit was used for plasma nitriding of specimens at a pressure of several millibars. The (Ti, Al)N coating was deposited onto all the samples using the same equipment as for the plasma deposition and low pressure plasma nitriding. For the characterization of the composite structures, the following methods were used: scratch test, X-ray diffraction analysis, scanning electron microscopy, scanning tunnelling microscopy and microhardness testing. It was found that plasma nitriding prior to coating deposition ...
A cross-flow atmospheric plasma jet with distilled water or analyte solution nebulization has been investigated. The plasma gas flows perpendicularly to the RF powered electrode (11.21 MHz) and a grounded electrode was added for plasma stabilization. The working parameters of the plasma generator can be controlled in order to maximize either the plasma power (75 W) or the voltage on the RF powered electrode (plasma power, 40 W). The plasma gas, pure argon (0.4 l min-1) or a mixture of argon (0.3-0.4 l min-1) and helium (0-0.2 l min-1), was also used for liquid nebulization. Optical emission of the plasma, collected in the normal viewing mode, was used for plasma diagnostics and for evaluating its excitation capabilities. The influence of helium content in the mixed-gas plasma on ...
In this paper the simulation of hybrid processes containing membrane units will be discussed. For this purpose a user-defined module for simulation and design of membrane processes was implemented into the simulation program AspenPlus. The advantages can be summarized as follows: - any combination of membrane processes with all other units already implemented in AspenPlus is possible, including internal recycle streams, - utilization of the physical property models and data bases of AspenPlus is possible, - cost and sensitivity analysis can be performed. These benefits are demonstrated in detail for a membrane vapor recovery unit for the treatment of tank farm off-gas, for a two-stage reverse osmosis plant for organic/-organic separations and for a combination of distillation and pervaporation for the separation of a dimethylcarbonate/methanol mixture. (orig.)
To investigate the variation in the fine structure of polyamide thin-film composite (TFC) membranes prepared via two different interfacial polymerization conditions (IP-I and IP-II), experiments on Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), water contact angle, and positron annihilation spectroscopy (PAS) coupled to a slow positron beam were conducted. Polyamide TFC membranes were prepared via the interfacial polymerization reaction between triethylenetetramine (TETA) and trimesoyl chloride (TMC) on the surface of a modified polyacrylonitrile (mPAN) membrane. Compared with the polyamide TFC membrane prepared via IP-I, the polyamide layer prepared via IP-II showed a shorter S plateau length (thinner thickness), a higher o-Ps intensity I3 value (higher free-volume con...
The development of calcium sulfate dihydrate (gypsum) mineral scale in reverse osmosis (RO) membrane desalting was investigated by direct real-time observation of crystal growth. Gypsum scaling studies were conducted in a specially modified plate-and-frame reverse osmosis cell fitted with an optical window, with dark-field membrane lighting arrangement within the membrane cell to enhance crystal boundaries and allow recording of digital surface images magnified through an optical microscope. The evolution of the surface number density (SND) of gypsum crystals resembled a sigmoidal population growth process with an increasing rate of crystal formation at higher solution supersaturation (with respect to gypsum) at the membrane surface. The rate of formation of new crystals declined as the su...
Equivalent circuit and electrical parameters for H-doped NH{sub 4}UO{sub 2}PO{sub 4}.3H{sub 2}O self supported membranes have been determined by impedance spectroscopy. The measurements were carried out with a dry membrane, at different temperatures, and a wet membrane in contact with different electrolyte solutions. Resistance values for the dry membrane decrease with temperature increase, which agrees with the weak protonic character of the H-doped ammonium uranylphosphate. On the other hand, differences in the electrical parameters, depending on the electrolyte considered were also obtained and are attributed to different conduction mechanisms. (Author).
An electrochemistry model was developed to analyse the J-V characteristics of a Proton Exchange Membrane (PEM) water electrolyzer for hydrogen production. The Butler-Volmer equation and water transport characteristics through electrolyte membrane were employed to simulate the electrode activation over-potential and membrane ohmic over-potential, respectively. The modeling results are found to agree reasonably well with experimental data published in the literature. The parametric simulations show that the ohmic over-potential is relatively small with typical water content in the membrane. Compared with the cathode over-potential, the anode over-potential is more significant and constitutes the major source of voltage loss. The high anode over-potential is due to the relatively slow oxidation kinetics, which is related to anode material property and microstructure. This model can be integrated with a ...
Since artificial organs are intended to replicate chemical processes, knowledge of chemical engineering is essential in their design so that they will function with the maximum efficiency. The most commonly used artificial organ is the artificial kidney, a machine that performs a treatment known as hemodialysis. This process cleanses the bodies of renal failure patients by dialysis and filtration which are simple physiochemical processes. Hemodialysis membranes act to remove accumulated uremia toxins, excess ions and water from the patient via the dialysate, and to supply from the dialysate those ions that are insufficient. This paper describes dialysis membranes and dialyzers for blood purification, the solute transport mechanism of the membrane, and a technical evaluation of the dialysis membrane. Lastly, the next generation of artificial kidney is reviewed. 71 refs., 12 figs., 7 tabs.
Several thin film composite nanofiltration membranes have been prepared by spin coating a sulfonated poly(ether ether ketone) solution on a polyethersulfone support, followed by thermal treatment. The most optimal developed nanofiltration membrane shows a clean water permeance of ~4.5Lm^-^2h^-^1bar^-^1 and a molecular weight cut off (MWCO) of ~500gmol^-^1. No irreversible changes in membrane performance have been observed after prolonged exposure (up to several weeks) of this membrane to solutions with a pH in the range 0-14. Compared to Desal-5-DK, the developed membrane displays a similar water permeance and a higher NaCl retention. In comparison to commercially available pH stable membranes, MPF-34 and NP030P, it reveals a higher water permeance. Permeance and MWCO analysis at varying p...
Two methods were used to label pig kidney microvillar membrane proteins from the luminal and cytoplasmic surfaces of closed membrane vesicles. The first method was lactoperoxidase-catalysed radioiodination. Lactoperoxidase and glucose oxidase were positioned inside or outside the vesicles, iodination being initiated by adding glucose and "1"2"5I. After electrophoresis of the proteins, asymmetric labelling patterns on radioautographs were observed. However the major disadvantage of this method was the high degree of intramembrane labelling of the fatty acid chains of membrane lipids. The second method overcame this disadvantage. A new hydophilic photoreagent, 3,5-di("1"2"5I)iodo-4-azidobenzenesulphonate, was transported by a Na"+-dependent system into microvillar vesicles, thus permitting labelling from either side of the membrane when the vesicles were photolysed. The activity of several microvillar ...
A series of cation exchange membranes was produced by impregnating and coating both sides of a quartz web with a Nafion solution (1100 EW, 10%wt in water). Inert filler particles (SiO_2, ZrO_2 or TiO_2; 5-20%wt) were incorporated into the aqueous Nafion solution to produce robust, composite membranes. Ion-exchange capacity/equivalent weight, water take-up, thickness change on hydration and ionic and electrical conductivity were measured in 1 mol dm"-"3 sulfuric acid at 298 K. The TiO_2 filler significantly impacted on these properties, producing higher water take-up and increased conductivity. Such membranes may be beneficial for proton exchange membrane (PEM) fuel cell operation at low humidification. The PEM fuel cell performance of the composite membranes containing SiO_2 fillers was examined in a Ballard Mark 5E unit cell. While the use of composite ...
In this article, the results of low-current gas-discharge plasma generator investigations carried out by a group of scientists from the Kazan' Aviation Institute are presented. When considered necessary, the results are compared with the data obtained by other authors. The basic configurations and theoretical calculation peculiarities of plasma generators are described. The electrical, thermal and energy characteristics of discharges in gas flows, as well as summarised empirical formulae and experimental data necessary for calculations and design of plasma devices are presented. (author)
A new multipellet long-pulse plasma fueling system is in operation on JET. In the initial experimental phase, a variety of plasma density profile shapes have been produced with peak to average values ranging up to 2.5 and peak plasma density up to 1.2 )times) 10/sup 20/m/sup )minus/3). 7 refs., 4 figs
The analysis of plasma density oscillations and ExB rotation of U-3M torsatron plasma was performed by UHR correlation reflectometry during the transport barrier formation. The connections between these characteristics and the phenomenon of inner and edge transport barrier formation were determined experimentally at the different values of HF power and plasma density.
Carbon fibre composite (CFC) was irradiated by hot plasma streams at plasma gun facility MK-200UG. The CFC targets were tested by plasma loads relevant to Edge Localized Modes (ELM) and mitigated disruptions in ITER. Onset condition of CFC evaporation and properties of evaporated carbon were studied by use of infrared pyrometry and visible spectroscopy.
The beams in electron linear colliders can be converted to nearly monochromatic photon beams by means of Compton backscattering of laser photons. The electron beams must then be diverted from the interaction point by some means, the best of which seems to be a plasma lens. This paper describes the constraints on the plasma lens in this application and shows how the ablation of solid hydrogen pellets might be able to produce plasmas to satisfy these constraints. ((orig.)).
Comparison of plasma density increase was carried out in outer and inner channels of the interferometer in T-11M tokamak. There were two cases of gas puffing: by outer valve or upper one. Amplitude of difference of the plasma density increase consisted of 9% near the outer valve. Perturbation of the electric potential e?1/Te can have similar value. This perturbation can lead to appearance of the additional losses.
Low pressure plasmas have some promising advantages for nitriding The separation of plasma generation from the workpiece overcomes several of the major drawbacks of conventional plasma nitriding and also allows independent control of ion flux and energy This opens the possibility of nitriding at lower temperatures so that the process can be extended to a wider range of materials and applications. Copyright (1999) Materials Australia
Based on the nonlinear dispersion relation of electromagnetic wave in relativistic plasma, the nonlinear controlling equation for linearly polarized mode is obtained using Karpman's method. The modulation instability of intense laser pulse propagating through relativistic plasma is analyzed and the modulation instability growth rate as a function of perturbation wave number for laser beam propagating through relativistic plasma is given. (authors)
The spontaneous evolution from ultracold Rydberg atoms to plasma is investigated in a caesium MOT by using the method of field ionization. The plasma transferred from atoms in different Rydberg states (n=22-32) are obtained experimentally. Dependence of the threshold time of evolving to plasma and the threshold number of initial Rydberg atoms on the principal quantum number of initial Rydberg states is studied. The experimental results are in agreement with hot-cold Rydberg-Rydberg atom collision ionization theory. (authors)
One of several methods to build YSZ electrolyte of SOFC is plasma spraying. This system heats particle to a melting point and then pushing them into target and forming a deposition. This paper presents heating studies of YSZ particle in plasma jet. By simple model it is shown that the required time such those YSZ particle with grain size of 50 ?m to be melt is around 12 x 10-4 second. (author)
The results of experiments received on the plasma focus (PF) device with energy stored equal 4 kJ are represented. Photos of the current plasma sheath (CPS), pre-pinch, sphere-like plasma formations are produced with help of the electron-optical converter contained a gated micro-channel plate (MCP) and the CCD-camera imaging system in the visible region. The redial velocity of the CPS is about 107 cm/s. Neon plasma electron density measured with help of the interferograms in the visible region and the spectra in the soft X-ray region is equals to 3?1018 cm-3. Electron temperature is equal to about 200 eV. Discharge integral photos were obtained with help of the soft X-ray pinhole camera. Pictures with 2 ?s resolution of the plasma luminescence above PF anode region were made by CCD-camera.
A detailed study has been performed for estimating the orbital energies, positions and shifts of the Lyman lines of C5+, Al12+ and Ar17+ under strongly coupled plasma with a view to understand such line positions and shifts obtained in laser produced plasma experiments. The effect of strongly coupled plasma has been treated within the Ion Sphere (IS) model. Both non-relativistic and relativistic methods have been used for estimating the spectral properties. Theoretical estimates with IS model of the plasma are in conformity with the results of laser plasma experiments on these highly stripped ions. The experimental data for the systems have also been compared with the theoretical estimates using Debye screening model of the plasma with spatial confinements which gives additional restrictions to the wave functions at finite boundaries.
The UTST (University of Tokyo Spherical Tokamak) device was constructed for the purpose of exploring the formation of ultra-high beta ST (Spherical Tokamak) plasma using the double null plasma merging method. When two plasmas merge together to form a single plasma, magnetic field lines reconnect, and the magnetic field energy is converted to the plasma kinetic energy, increasing the plasma beta. The merging start-up has been demonstrated in the TS-3/4, START and MAST devices using coils inside the vacuum vessel and TS-3 plasma obtained 50% beta. In order to demonstrate the start-up in a more reactor relevant situation, UTST has all poloidal field coils outside the vacuum vessel. The first plasma experiment on the UTST was performed from December, 2007. In the result, the plasma obtained 10 kA by ...
Low pressure silane plasmas are known for their ability to synthesize silicon nanoparticles via gas phase nucleation. While in the past this particle formation has often been considered from the viewpoint of a contamination problem in semiconductor processing, we here describe a silane low pressure plasma that enables the synthesis of highly oriented, cubic-shaped silicon nanocrystals with a rather monodisperse size distribution. These silicon nanocubes have successfully been used in the manufacture of single nanoparticle vertical transistors. We discuss the advantages of this new paradigm of building nanoelectronic devices. The plasma synthesis process is characterized in more detail than in prior work. The particle nucleation, growth and shape evolution are studied. Results indicate that the process provides two spatially distinct zones: a diffuse plasma for particle growth and a constricted ...
The possibility of surface modification of high-speed steel cutting tool by means of vacuum-plasma treatment including ion nitriding in gas plasma followed by the deposition of wear resistant (Ti, Al)N coatings in metal-gas plasma of a vacuum arc discharge is studied. The regularities of nitrided layer formation and the structure of these layers under various operation conditions of cutting tool are investigated. Optimum conditions of vacuum-plasma treatment providing the best wear resistance of cutting are determined
Thomson scattering is the process in which a low-energy photon scatters from a free electron. When a laser pulse propagates through a plasma, the spectrum of the scattered light due to the Thomson scattering is proportional to the power spectrum of the electron density fluctuations, i.e., dynamic form factor, from which various plasma parameters can be inferred, such as electron temperature and plasma flow velocity. After years of development. Thomson scattering has now become a powerful diagnostic tool of plasma physics. (authors)
The paper presents results of experimental research on the interaction of a pulsed plasma-ion stream with a tungsten (W) target. The pulsed hydrogen plasma was produced within the RPI-IBIS (Multi-Rod Plasma Injector) facility at IPJ in Swierk. Measurements were carried out by means of optical spectroscopy and corpuscular diagnostic techniques. For experiments with the W-target the operational conditions (so-called PID mode) were chosen when a clean hydrogen plasma stream was generated. Attention was paid to the identification of WI and WII spectral lines.
An experiment of a plasma torch on a production foundry cupola is reported. The test runs were conducted on a hot blast cupola, the blast temperature in the absence of plasma being 400 C. With the torch, the temperature of the blast was increased to 1000 C. The experiment was conducted for the manufacture of car engines with a 2.5 MW transportable plasma system. The cupola was boosted with a 4 MW torch and results included an increase in production of 45 percent, a decrease in coke rate and no more new iron in the loads. The plasma torch and hot air cupola furnace are described.
A study is made into microhardness and structure of coatings on various system steels (37G2S, 25Kh5M, R6M5), obtained by ion nitriding in a low pressure (10"-"1 Pa) arc discharge plasma. A comparison of properties is accomplished for steels nitrided in an arc gas discharge and in a furnace. It is stated that ion-plasma nitriding in an arc gas plasma generator is an efficient method of alloy steels hardening which allows changing the structure and increasing the hardness of a surface layer up to rather great depth
This paper presents the first results of a study of plasma nitriding in various regions of a d.c. glow discharge, i.e. on the cathode, on the anode, and on a substrate isolated from the cathode and anode (at plasma potential). The results obtained reveal differences in the growth kinetics and surface morphology of the nitriding layers, depending on the region where the nitriding process took place. The aim of this work was to study the role of low temperature plasma in the plasma nitriding process. The processes were carried out in an apparatus for plasma treatment with a hot anode. (orig.)
The measurement of electron densities using interferometry and refraction measurements in plasmas with cross-sections where the electron density contours are concentric ellipses is examined. Transforms are found for both interferometrically deduced optical path-length differences and refraction angle data obtained from elliptical cross-section plasmas. The transformed data can be inverted to give electron densities using standard techniques developed for circular cross-section plasmas. Refraction of light in elliptical cross-section plasmas is examined using numerical ray tracing.
Currentless plasma in Uragan-3M (U-3M) is produced and heated by absorption of RF power in the region of Alfven waves (AW). The process of plasma heating was explained in (2) as a result of Cherenkov absorption of energy of the fast (EM) and slow (kinetic Alfven) waves by electrons and turbulent ion heating due to excitation of short wave ion Bernstein waves (IBW). In this report we present results of studies of plasma density fluctuations showing existence of a narrow bands near the frequencies of ? ? n?ci (n=1,2,3).
Electrostatic plasma simulation code for 2D rectangular geometry is presented. Main distinguishing feature of the code is its orientation on the beam-plasma interaction. The code and its graphical interface were developed using MATLAB programming language. Simulation results of inhomogeneous plasma interaction with modulated electron beams of different width are compared. In case of wide beam the front of Langmuir waves generated in point of local plasma resonance is planar and in case of thin beam (or ribbon beam) the front has approximately half-circular form.
It is well known that contact with metals can be responsible for allergic contact dermatitis; also, there is experimental evidence that nickel ions are readily available on the surface of used coins containing nickel and copper. The aim of this study was to prove that metal powders of nickel (Ni), cobalt (Co) and chromium (Cr) dispersed in synthetic sweat are oxidised into respective ions that can permeate the skin. Suspensions of 5 g of metal powder (Ni, Co and Cr) in 100 mL of synthetic sweat at pH 6.5 were prepared and shaken with a stirring plate at room temperature for 30 min. Human skin membranes were set up in Franz-diffusion cells and 2 mL of the freshly made suspension were applied to the outer surface of the skin for 24h. The appearance of metal ions in the aqueous receptor phase (NaCl 0.9%) was quantified by Electro Thermal Atomic Absorption Spectroscopy (ETAAS). Also, metals ions were analysed using Differential Pulse Polarography (DDP), Differential ...
The most striking achievement in magnetic fusion experiments during last few years was the discovery of plasma detachment from material targets, a much needed effect for plasmas with high power fusion parameters. Due to the very low heat loads on the targets observed in these regimes and potentially low erosion of the targets, detached regimes look attractive from the International Thermonuclear Experimental Reactor (ITER) design point of view. Thus the author has experimental proof for the possibility for a co-existence of fusion relevant hot plasma in the core and a low temperature partly ionized plasma at the edge of magnetic fusion device. Although somewhat similar behavior of edge plasma was considered theoretically even before plasma detachment was found experimentally, it was not clear in the beginning how these theoretical and experimental findings would ...
In vacuum arcs of interest for ion deposition, in which a magnetic filter is used, significant plasma rotation about the filter axis can develop. In the present work we present experimental evidence and simplified models to interpret relatively fast rotation of plasma generated in a pulsed vacuum arc with a straight magnetic filter and with a magnetic field strength in the range 52-430 G. The plasma rotation is produced in the first part of the filter (the driving region) where either the expanding or the contracting plasma encounters a mainly axial magnetic field. In the next part of the filter (the rotation region) a quasi-equilibrium is achieved and the plasma does not evolve further significantly. A rigid-rotor type of equilibrium is considered to model the rotation region, with experimentally obtained parameters, and a simple model is employed in the driving region to quantify ...
The paper presents the investigations of plasma streams generated by pulsed plasma gun 'Prosvet' operated with different gases: krypton (m=84) and helium (m=4). Contour parameters of working gas spectral lines (full intensities and half-widths) are used for determination of spatial distributions of the electron density and temperature. Temporal distributions of the spectral lines intensities (both neutrals and ions of working gas), impurity spectral lines and continuum intensities are analyzed. Plasma stream velocity was estimated by time-of-flight method between two monochromators (MUM) connected with photo-multiplier. longitudinal distributions of the plasma pressure for different time moments and varied distances from the accelerator output have been used for investigation of the plasma stream dynamics and study the plasma compression in the focus region for ...
In this work, the silicon oxynitride layer was studied as a tunneling layer for non-volatile memory application by fabricating low temperature polysilicon thin film transistors on glass. Silicon wafers were oxynitrided by only nitrous oxide plasma under different radio frequency powers and plasma treatment times. Plasma oxynitridation was performed in RF plasma using inductively coupled plasma chemical vapor deposition. The X-ray energy dispersive spectroscopy was employed to analyze the atomic concentration ratio of nitrogen/oxygen in oxynitride layer. The oxynitrided layer formed under radio frequency power of 150 W and substrate temperature of 623 K was found to contain the atomic concentration ratio of nitrogen/oxygen as high as 1.57. The advantage of high nitrogen concentration in silicon oxide layer formed by using nitrous oxide plasma was investigated by ...
In this work, the silicon oxynitride layer was studied as a tunneling layer for non-volatile memory application by fabricating low temperature polysilicon thin film transistors on glass. Silicon wafers were oxynitrided by only nitrous oxide plasma under different radio frequency powers and plasma treatment times. Plasma oxynitridation was performed in RF plasma using inductively coupled plasma chemical vapor deposition. The X-ray energy dispersive spectroscopy was employed to analyze the atomic concentration ratio of nitrogen/oxygen in oxynitride layer. The oxynitrided layer formed under radio frequency power of 150 W and substrate temperature of 623 K was found to contain the atomic concentration ratio of nitrogen/oxygen as high as 1.57. The advantage of high nitrogen concentration in silicon oxide layer formed by using nitrous oxide plasma was investigated by ...
Water transport in conifers occurs through single-celled tracheids that are connected to one another via intertracheid pit membranes. These membranes have two components: the porous margo, which allows water to pass through the membrane, and the impermeable torus, which functions to isolate gas-filled tracheids. During drought, tracheids can become air filled and thus hydraulically dysfunctional, a result of air entering through the pit membrane and nucleating cavitation in the water column. What are the hydraulic tradeoffs associated with cavitation resistance at the pit level, and how do they vary within the structural components of the intertracheid pit? To address these questions, we examined pit structure in 15 species of Cupressaceae exhibiting a broad range of cavitation resistances. Across species, cavitation resistance was most closely correlated to the ratio of the torus to pit aperture ...
The PERMCAT process chosen for the final clean-up stage of the Tokamak Exhaust Processing system of the ITER tritium plant combines in a single component a catalytic reactor and a permeator using Pd/Ag membranes. This study covers the mechanical behaviour of a Pd/Ag membrane under different operating conditions. The consequences of hydrogen uptake by the membrane during nominal operation but also during off-normal events are presented. Depending on the operating conditions, expansions around 2% and significant deformations are observed. Different mechanical designs of PERMCAT reactors are then discussed. The first generation comprises finger-type membranes and two new mechanical designs use either additional edge welded bellows or a special corrugated Pd/Ag membrane. These upgraded designs improve the robustness and simplify the geometry of the component. The experimental validation ...
The PERMCAT process chosen for the final clean-up stage of the Tokamak Exhaust Processing system of the ITER tritium plant combines in a single component a catalytic reactor and a permeator using Pd/Ag membranes. This study covers the mechanical behaviour of a Pd/Ag membrane under different operating conditions. The consequences of hydrogen uptake by the membrane during nominal operation but also during off-normal events are presented. Depending on the operating conditions, expansions around 2% and significant deformations are observed. Different mechanical designs of PERMCAT reactors are then discussed. The first generation comprises finger-type membranes and two new mechanical designs use either additional edge welded bellows or a special corrugated Pd/Ag membrane. These upgraded designs improve the robustness and simplify the geometry of the component. The experimental validation ...
This project will determine whether electrolytic dialysis has promise in the separation of charged particles in an aqueous solution. The ability to selectively move ions from one aqueous solution to another through a semipermeable membrane will be studied as a function of emf, amperage, and particle electrical charge. The ions selected for the study are Cl{sup -} and SO{sub 4}{sup 2-}. These ions are of particular interest because of their electrical conduction properties in aqueous solution resulting with their association with the corrosive action of metals. The studies will be performed with commercial membranes on solutions prepared in the laboratory from reagent salts. pH adjustments will be made with dilute reagent acid and base. Specific objectives of the project include testing a selected membrane currently available for electrolytic dialysis, membrane resistance to extreme pH conditions, the ...
An evaporator using a hydrophobic membrane made from a polytetrafluoroethylene (PTFE) was developed to improve DF (Decontamination Factor) and to reduce evaporator size. The membrane distillation, provided by the evaporator, is a new technique for liquid purification. Fundamental experiments were carried out to develop the membrane filter (tube type, outer diameter, 8 mm; membrane thickness, 500 {mu}m) for radioactive liquid treatment. The continuous operation test using actual liquid waste was also made during about 3,000 h. (This is almost equal to the operation time of an actual evaporator per year.) The evaporation rate decreased with increase an operation time due to contamination of waste impurity. But the rate was recovered by washing the membrane with hot water and then drying it. DF was over 10{sup 4} which is ten times larger than that for a conventional system. A pilot ...
This project is concerned with the structure and function of the unique antenna system found in the green photosynthetic bacteria. The antenna system in these organisms is contained within a vesicle known as a chlorosome, which is attached to the cytoplasmic side of the cell membrane. Additional antenna pigments and reaction centers are contained in integral membrane proteins. Energy absorbed by the bacteriochlorophyll c (BChl c) pigments in the chlorosome is transferred via a ``baseplate`` array of BChl a antenna pigments into the membrane and to the reaction center. This system is similar in some respects to the phycobilisome antenna system found in cyanobacteria and some types of algae, in that a membrane-associated structure absorbs light and transfers it to the membrane where conversion to chemical energy takes place. However, the overall structure, the type of pigments ...
The properties of AlN make this material very attractive for optical, electronic, and tribological application. Also, if the AlN could be formed on the Al surface to enhance its surface properties, Al could be applied for the lightening of machine parts. However, a dense oxide film exists on the surface of Al, which prevents the formation of the Al nitride even during plasma nitriding and plasma coating process. In this study, plasma nitriding has been tried to form an AlN layer on Al after the surface activation processes. During the plasma nitriding, the density of the nitrogen ions was amplified by means of controlling the power of the Al substrates. The film thickness, microstructural features and the mechanical properties such as hardness and wear properties of the AlN layer were examined as a function of the process parameters of pretreatment and plasma nitriding
The opportunity of use self-maintained plasma-beam discharge in an extended pulsing plasma diode of low pressure for making powerful sources of the soft X-rays is investigated. Conditions of formation of the self-maintained plasma-beam discharge are determined. The mode of making of dense high-temperature plasma on the basis of stannum ions in the discharge is shown. The stannum ions are used as a working element of a radiation sources at pulsing power of electron beam P?10...100 MW. Results of the examination on formation of the dense (np?1016 cm3), small sizes (le?100 eV in conditions of working material evaporation from the anode are given. The total contribution of energy to the discharge has made W < 20 J.
This study was the analyse the relationship between properties of ion nitrided Fe sintered material and parameters of plasma nitriding process. Pure fe sintered materials (relative density : 92%) were fabricated by hot-pressing and nitrided under pulsed DC plasma for 4 hours. The large number of parameters in plasma diffusion treatment allows close control of the process so that surface layers with defined microstructures and properties can be obtained. The number of micropores in nitriding layer can be reduced in pulsed DC plasma by reducing the plasma power and by varying the gas mixture. The phase constitution of compound layer of nitrided Fe sintered material were influenced by gas mixture (N{sub 2} : H{sub 2}) and pulsed ratio (pulse on/off time ratio)
This study was the analyse the relationship between properties of ion nitrided Fe sintered material and parameters of plasma nitriding process. Pure fe sintered materials (relative density : 92%) were fabricated by hot-pressing and nitrided under pulsed DC plasma for 4 hours. The large number of parameters in plasma diffusion treatment allows close control of the process so that surface layers with defined microstructures and properties can be obtained. The number of micropores in nitriding layer can be reduced in pulsed DC plasma by reducing the plasma power and by varying the gas mixture. The phase constitution of compound layer of nitrided Fe sintered material were influenced by gas mixture (N_2 : H_2) and pulsed ratio (pulse on/off time ratio).
The concept of the self-focusing plasma lens in various beam-plasma interaction regimes is reviewed. We found that in order for current neutralization to occur, it is only necessary to attain the condition {ital k}{sub {ital p}}{sigma}{sub {ital x}}{approx_gt}1, and not {ital k}{sub {ital p}}{sigma}{sub {ital y}}{approx_gt}1, for flat beams. This helps to substantially reduce the required plasma density for beamstrahlung suppression. We also report on a recent calculation on the detector backgrounds induced by a plasma lens. It is shown that these backgrounds are within the tolerance of all major components in a NLC-like detector. Finally, one other potential application of plasma lens for {gamma}{gamma} colliders is discussed.{copyright}{ital American Institute of Physics.}
The concept of the self-focusing plasma lens in various beam-plasma interaction regimes is reviewed. We found that in order for current neutralization to occur, it is only necessary to attain the condition k_p#sigma#_x approx-gt 1, and not k_p#sigma#_y approx-gt 1, for flat beams. This helps to substantially reduce the required plasma density for beamstrahlung suppression. We also report on a recent calculation on the detector backgrounds induced by a plasma lens. It is shown that these backgrounds are within the tolerance of all major components in a NLC-like detector. Finally, one other potential application of plasma lens for #gamma##gamma# colliders is discussed.copyright American Institute of Physics.
In this paper a novel method is presented, based on the use of plasma processing, to suppress the transient enhanced diffusion of boron implanted in silicon. We found for silicon samples processed with plasma and subsequently boron implanted that the anomalous diffusion of the dopant atoms at the beginning of the annealing process is almost completely suppressed. This phenomenon is interpreted in terms of capture of the ion beam generated interstitials by the dislocations induced by the plasma processing. At room temperature the dislocations are observed to grow in size after the boron implant, attesting their efficiency as trapping centres for interstitials. Moreover, varying the plasma process conditions we can establish a general relation between the presence of the trapping centres induced by the plasma processing and the suppression of the transient diffusion.
It is a traditional method to diagnose electron-cyclotron-resonance (ECR) plasma source, using a single probe to measure the current-voltage curve of the plasma, based on which and theoretic formula the plasma density can be computed. The article adopts a Langmuir probe having a role of emission electrons to measure two different current-voltage curves with and without emission. It is ease to get the plasma potential via the inflexion of the two curves and compute directly various physical quantities by the assistant computer, such as electron temperature, electron/ion density, plasma potential etc. The deviation is about percent 1.8 between the measurement results by traditional and the new method, but the latter has higher efficiency. (authors)
An estimation method of plasma density based on surface plasmons theory for surface-wave plasmas is proposed. The number of standing-wave is obtained directly from the discharge image, and the propagation constant is calculated with the trim size of the apparatus in this methods, then plasma density can be determined with the value of 9.1 x 1017 m-3. Plasma density is measured using a Langmuir probe, the value is 8.1 x 1017 m-3 which is very close to the predicted value of surface plasmons theory. Numerical simulation is used to check the number of standing-wave by the finite-difference time-domain (FDTD) method also. All results are compatible both of theoretical analysis and experimental measurement. (authors)
A new method of plasma treatment for powder particles was investigated. A glass bottle horizontally held on a rotating system was used for the treatment. The outside of the bottle was covered by the grounded metal net, and the rod electrode was provided at the center of the bottle, which was connected to an ac high voltage source. Powder particles were placed in the bottle with stainless steel beads of large diameter and the plasma was generated between two electrodes and while the bottle was rotating. Using this system, powder particles were uniformly plasma-treated without coagulation. After 40 seconds treatment with plasma of 0.55 W in Ar gas, the charge to mass ratio for polyethylene powder particles having 160 {mu}m mean diameter generated by stainless before treatment. (author)
This chapter consists of some points including an introduction, the basic parts of mass spectroscope device, sample introduction into the inductively coupled plasma, pneumatic nebuliser, ultrasonic nebuliser, dry gas cloud system, laser ablation unit, inductively coupled plasma-ion source, extraction of ions from ion source, mass analysis, quad-polar mass spectrometer, dual assembly mass spectrometer, mass spectrometer by calculation of time of flight, ion interferences and the ability of resolution, ion counter, working conditions of inductively coupled plasma mass spectroscope device, efficiency of ion transportation in an inductively coupled plasma mass spectroscope device and applications of analysis using mass spectroscope of induced plasma including nuclear, industrial, geological, environmental and archaeological applications, measurement of isotopes ratio and applications in ...
A high sensitivity, high bandwidth, two-color interferometer (1064 and 532 nm) has been tested on the Hawk pulsed power generator at the Naval Research Laboratory. The phase resolution is 10"-"5 waves with a rise time of 3 ns, a new capability for diagnosing plasmas, and neutrals in pulsed power experiments. The two-color feature is used to distinguish phase shifts from free (plasma) electrons and bound (neutral and ion) electrons. Simultaneous electron and neutral density measurements were demonstrated in a plasma opening switch (POS) experiment. The ability to measure small phase shifts with fast rise time were demonstrated in a plasma filled diode experiment. The high sensitivity and vibration isolation enable neutral gas distribution measurements from supersonic nozzles used in plasma radiation source experiments. Examples of these measurements and future applications are ...
We study the static potential of open bosonic membranes in the 1/d approximation, where d is the space-time dimensionality. For a fixed square boundary of side length R we find, in contrast to the string potential, no critical distance below which tachyons appear. Instead, we find a correction factor to the classical potential, V/sub cl/=kR/sup 2/, which for small distances shifts the perturbative ground state energy by a positive constant. We interpret the shift as the mass gap of this quantum membrane.
The analgesic, dipyrone (1,phenyl-2,3-dimethyl-5-pyrazolone-4-methylamino methane sulphonate sodium), at 20 mM concentration, inhibited the rejoining of single-strand scissions in DNA of Escherichia coli B/r cells induced by 20 krad gamma-radiation. The chemical altered the cell membrane structure as evidenced from the uptake of acriflavin, the efflux of potassium ions from the bacterial cells and the inhibition of alkaline phosphatase-a cell membrane associated enzyme. (author). 18 refs., 6 figures.
The analgesic, dipyrone (1,phenyl-2,3-dimethyl-5-pyrazolone-4-methylamino methane sulphonate sodium), at 20 mM concentration, inhibited the rejoining of single-strand scissions in DNA of Escherichia coli B/r cells induced by 20 krad gamma-radiation. The chemical altered the cell membrane structure as evidenced from the uptake of acriflavin, the efflux of potassium ions from the bacterial cells and the inhibition of alkaline phosphatase-a cell membrane associated enzyme. (author).
Nitrate microelectrodes and ORP microelectrodes were fabricated to study the denitrification characteristics of dynamic membrane at different COD loadings. The denitrification process was found at 0.6-1 mm depth beneath the interface of biofilm/bulk. The results of ORP microelectrode also demonstrated that the ORP value in the range of denitrification area was between 88.6 approximately -128.4 mV which was appropriate to denitrification. When the COD loading was 0.45 kg/(m3 x d), the denitrification rate (NO3- -N) was the maximum of 0.6347 x 10(-6 mol/(L x s). With the increase of COD loading, the denitrification area was increasing and two layers with different denitrification rates emerged in the dynamic membrane. The phenomenon implied the effect of organic concentration, oxygen concentration and bacterial competition on the denitrification rate. PMID:17117632
A study was made of the uncoupling action of polychlorinated biphenyls (Kanechlor-400) on oxidative phosphorylation in rat liver mitochondria. Kanechlor-400 (KC-400) at 20 ..mu..g/ml stimulated state 4 respiration of rat liver mitochondria more than 4-fold with ..cap alpha..-ketoglutarate/malate as a substrate, and released the oligomycin-inhibited state 3 respiration. KC-400 also dissipated the membrane potential across the mitochondrial membranes; thus, it acts as an uncoupler of oxidative phosphorylation in rat liver mitochondria. KC-400 altered the permeability properties of mitochondrial membranes as evidenced by the release of endogenous K/sup +/ and the oxidation of exogenously supplied NADH. It is concluded that KC-400 produces a nonspecific increase in mitochondrial ion permeability, thereby dissipating membrane potential, which leads to the uncoupling.
Scanning electron microscope (SEM) is necessary to demonstrate presence or absence of pit membranes in possible perforations or the type of pit membrane remnants in perforations in vessel element end-walls of angiosperms, but it was unconfirmed and questionable whether pit membrane absence in pits was affected by the processing and handling before SEM observations. To solve this question, the secondary xylem of four woody species from primitive angiosperms, Illicium henryi Diels. (Illiciaceae), Schisandra rubriflora (Franch.) Rehd. et Wils. (Schisandraceae), Tetracentron sinensis Oliv. and Trochodendron aralioides Sieb. & Zucc. (Trochodendraceae) was chosen and the following techniques were used: (1) fresh materials were examined in low-vacuum with ESEM. (2) Air-dried materials were examin...
A novel thin-film composite polyamide nanofiltration membrane was prepared through interfacial polymerization of polymeric polyamine polyvinylamine (PVAm) with isophthaloyl chloride (IPC) on a polysulfone supporting film. The composite membranes were prepared under different conditions and characterized in terms of chemical and morphological structures, surface zeta potential, pure water permeability, and rejection to different solutes including electrolytes and sucrose. The results showed that the membrane performance was significantly affected by the content of amine units of PVAm and the concentrations of PVAm and IPC. The increase of the content of amine units of PVAm and the concentration of IPC resulted in an augment in salt rejection and a decrease in permeability, while the increas...
Decreased membrane rigidity is one of the characteristics of malignant cells, resulting in part from the desaturation of stearic acid into oleic acid. In this study we investigated the influence of...Full Text Available
A novel composite charged mosaic membrane (CCMM) was prepared via interfacial polymerization (IP) of polyamine [poly(epichlorohydrin amine)] and trimesoyl chloride (TMC) on the polyethersulfone (PES) support. Fourier transform infrared spectroscopy (FT-IR), environmental scanning electron microscopy (ESEM), atomic force microscopy (AFM) and water contact angle analysis were applied to characterize the resulted CCMM. The FT-IR spectrum indicates that TMC reacts sufficiently with polyamine. ESEM and AFM pictures show that the IP process produces a dense selective layer on the support membrane. The water contact angle of the CCMM is smaller than that of the substrate membrane because of the cross-linked hydrophilic polyamine network. Several factors affecting the IP reaction and the performan...
Abstract The electrochemical properties of a perfluorosulfonic acid (PFSA) membrane are estimated using a combination of molecular dynamics simulation and statistical thermodynamic model. We obtain all parameters in an ionic conductivity model from an atomistic simulation and remove all adjusted model parameters. From a microscopic point of view, the hydrated PFSA membrane shows micro-phase segregation which separated into hydrophilic and hydrophobic phases. Our present work originates with this phenomenon and we treat this phase segregation as if it is a continuous phase for each of which the proton (H+) is transported inside the PFSA membrane/solvent (water and alcohols) mixture. The chemical potential for a given system is estimated using a molecular simulation technique to predict the ...
A dense Pd-Ag membrane reactor (MR) with 100% hydrogen selectivity packed with either Rh/La2O3 or Rh/La2O3-SiO2 as catalysts was used to carry out the dry reforming of methane. The membrane reactor simulation was performed using a well-known reactor model. For this purpose, we employed the equations derived from complete kinetic studies of the dry reforming of methane reaction in connection with both catalysts. In addition, we developed the kinetic equation for the reverse water gas shift reaction (RWGS). The combination of detailed kinetic studies with the measured permeation flux for the Pd-Ag membrane allowed a complete comparison between experimental and simulated operation variables. The variables studied for both catalysts were methane conversion and hydrogen permeation as a function...
Certain allelochemicals of the marine dinoflagellate Alexandrium tamarense cause lysis of a broad spectrum of target protist cells but the lytic mechanism is poorly defined. We first hypothesized that membrane sterols serve as molecular targets of these lytic compounds, and that differences in sterol composition among donor and target cells may cause insensitivity of Alexandrium and sensitivity of targets to lytic compounds. We investigated Ca^2^+ influx after application of lytic fractions to a model cell line PC12 derived from a pheochromocytoma of the rat adrenal medulla to establish how the lytic compounds affect ion flux associated with lysis of target membranes. The lytic compounds increased permeability of the cell membrane for Ca^2^+ ions even during blockade of Ca^2^+ channels wit...
In situ synthesis of silver chloride (AgCl) nanoparticles was carried out under ambient conditions in nanoporous bacterial cellulose (BC) membranes as nanoreactors. The growth of the nanoparticles was readily obtained by alternating dipping of BC membranes in the solution of silver nitrate or sodium chloride followed by a rinse step. X-ray diffraction (XRD) patterns indicated the existence of AgCl nanoparticles in the BC and scanning electron microscopy (SEM) images showed that the AgCl nanoparticles well dispersed on the surface of BC and penetrated into the BC network. The AgCl nanoparticle-impregnated BC membranes exhibited high hydrophilic ability and strong antimicrobial activity against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive). The preparative proced...
Hydrophobic labelling is frequently used in the study of membrane-inserted domains of intrinsic proteins. However, the published procedures, fail to incorporate sufficient radioactivity into membrane immunoglobulins of B lymhocytes to permit investigation of their subunit structures and associations with other proteins. In order to increase the specific radioactivity of ["1"2"5I]iodonaphtylazide ["1"2"5I]INA), an improved method for the synthesis of the reagent was developed. In addition, the optimal conditions for labelling B lymhpocytes with ["1"2"5I]INA and commercially available reagent 3-(trifluoromethyl)-3-(trifluoromethyl)-3-(3'-["1"2"5Iliodophenyl)diazirine (["1"2"5I]TID were isolated and analysed in detail by SDS-PAGE. The usefulness of the two reagents for the investigation of lipid-embedded domains of membrane proteins is discussed. (author). 28 refs.; 4 figs.
In this paper, the design of large thin PIN detector with a membrane stress avoidance configuration is proposed, and the related device fabrication process is developed. Ultra-thin PIN detector {approx} 1.13 cm{sup 2} in area is fabricated on a thin ( {approx} 35{mu}m) silicon membrane, and characterized. Detector performance improvement has been successfully demonstrated. With the membrane stress avoidance design, the improved detector exhibits a leakage of 6nA, which is at least 5 times lower than that of detector of identical junction area. The new detector features a full depleted capacitance of 110 pF, and a FWHM of 40.86 keV energy resolution for 5.486 MeV alpha particle spectrography.
Functional properties of commercial and membrane processed pea protein isolates (PPI) prepared from yellow peas were investigated. Four protein isolates were prepared from yellow pea flour using water and KCl extractions at 25^oC followed by ultrafiltration and diafiltration (UF and DF) at pHs of 7.5 and 7.5 or 6 respectively. Following assessment of compositional attributes; solubility, foaming, flow and dynamic rheology, emulsification ability and heat-induced textural and rheological properties of prepared PPIs and a commercially available PPI were tested and compared. Membrane purification of proteins resulted in 28% to 68% reduction in phytic acid and enhanced, comparatively, the tested functional properties. Solubility of membrane processed PPIs, at all tested pHs, was superior and t...
We identify new organelles associated with the vacuolar system in plant cells. These organelles are defined biochemically by their internal content of three integral membrane proteins: a chimeric reporter...Full Text Available
This paper evaluates the performance of asphalt membranes by examining the chemical and permeability changes experienced by the asphalt during aging tests. The aging process was accelerated by exposing the asphalt to elevated temperatures, high oxygen concentrations, and increased strengths of aqueous oxidizing agents. The synergistic effects of the variables are evaluated by using a fractional factorial experimental design. The installation costs for a catalytically airblown asphalt liner are roughly half that of the typical polymeric materials, and also less than the rubberized asphalt membrane. The results of the initial accelerated aging tests of the asphalt membranes indicate that this material will provide stable, long-term leachate isolation in a mill tailings environment.
BackgroundThe permeabilization of mitochondrial membranes is a decisive event in apoptosis or necrosis culminating in cell death. One fundamental mechanism by which...Full Text Available
Symmetrical, extracellular fibrils, which are related to the "special fibrils" of the dermis described by Palade and Farquhar, have been found along the outer surface of the basement membrane covering...Full Text Available
When a plasma becomes contaminated by foreign particles, generically referred to as dust, the result is called a dusty plasma. At the present time there is a great deal of interest in dusty plasmas because of their roles in terrestrial and extra-terrestrial processes - semiconductor processing, high temperature fusion experiments, stellar formation and the rings of Saturn. This thesis is concerned with the role of dust in processing type plasmas. In the following experiments, artificial dust is introduced into a parallel electrode plasma chamber. Ions and electrons in the plasma charge the dust particles and they become suspended in the plasma due to the balancing of electric and gravitational forces. By illuminating the suspended dust with laser light and using an extremely high speed camera fitted with a macro lens to look at the scattered ...
By means of an audio frequency plasma polymerisation ultra-thin gradient plasma polymer layers were deposited on zinc and zinc-coated iron. The aim was to generate an interfacial polymeric layer which bonds to an oxidised metal as well as to a subsequently applied organic coating and acts as an interfacial barrier layer for ions and water. Surface modifications were done in an in situ plasma cell with infrared reflection absorption spectroscopy (IRRAS). The zinc surface was first activated by an oxygen plasma to provide a freshly oxidised and contamination free oxide surface. The intermediate stages of the surface reactions could be revealed. Carbon dioxide molecules as oxidation products adsorbed on the growing zinc oxide and were desorbed at a later stage. An organosilicon plasma polymer was deposited directly on top of the oxide layer from a hexamethyldisilane (HMDS) ...
The present invention relates to a method of recycling polymeric waste products into monomers and high value forms of carbon by pyrolytic conversion using an induction coupled RF plasma heated reactor.
Abstract in english We present a detailed derivation of the effective dielectric constant to be used in the dispersion relation for electrostatic waves in the case of a plasma immersed in a inhomogeneous magnetic field, with inhomogeneity perpendicular to the direction of the magnetic field.
The Ti-6Al-4V alloy was treated by inductively coupled rf plasma nitriding. The effects of plasma-processing time in the range of 5-35 min on the microstructure and the mechanical properties of the plasma-nitrided Ti-6Al-4V samples were studied. The plasma power input was adjusted at 450 W and pure N{sub 2} gas was introduced to establish a treatment pressure of 8.0-8.4 x 10{sup -2} mbar. The characteristics of the nitrided layers have been investigated by microhardness testing, surface roughness measurements, optical microscopy, and x-ray diffraction. The results show that the surface microhardness increases as the plasma-processing time increases to reach 2000 HV0.1 at a plasma-processing time of 35 min. A high nitriding rate of 2.81 {mu}m{sup 2} s{sup -1} at a plasma-processing time of 25 min was achieved. The formation of the hard phases ...
The Ti-6Al-4V alloy was treated by inductively coupled rf plasma nitriding. The effects of plasma-processing time in the range of 5-35 min on the microstructure and the mechanical properties of the plasma-nitrided Ti-6Al-4V samples were studied. The plasma power input was adjusted at 450 W and pure N_2 gas was introduced to establish a treatment pressure of 8.0-8.4 x 10"-"2 mbar. The characteristics of the nitrided layers have been investigated by microhardness testing, surface roughness measurements, optical microscopy, and x-ray diffraction. The results show that the surface microhardness increases as the plasma-processing time increases to reach 2000 HV0.1 at a plasma-processing time of 35 min. A high nitriding rate of 2.81 #mu#m"2 s"-"1 at a plasma-processing time of 25 min was achieved. The formation of the hard phases TiN, Ti_2N, and ...
A 750 J plasma coaxial accelerator is used to produce plasma using air at 0.2 torr pressure and 8 kv charging voltage. The discharge current and voltage traces showed that the total circuit inductance was about 1750 ?H. The experimental results showed that the plasma sheath reached the muzzle after 6 ?s with velocity equal to 4 cm/?s, after then it decreased, while the simulation model showed that the plasma sheath reaches the muzzle with velocity of 3 cm/?s and after one microsecond it increases to reach about 4 cm/?s after 12 ?s then it decreased. The plasma temperature measurements showed that the plasma sheath reached the muzzle with temperature of about 9 eV and increase to reach about 12 eV after 8.5 ?s then after it decrease. The simulation model showed that the plasma temperature at the muzzle is about 10.5 eV and continue to ...
The stability of prothrombin and factor VII was studied using accelerated degradation tests in three preparations of freeze-dried pooled normal plasmas. In a previous report (Brozović, Gurd,...Full Text Available
The effects of homologous plasma HDL and VHDL fractions on established atherosclerotic lesions were studied in cholesterol-fed rabbits. Atherosclerosis was induced by feeding the animals a 0.5% cholesterol-rich...Full Text Available
Using plasma glutathione S-transferase measurements hepatocellular integrity was assessed in groups of hyperthyroid and hypothyroid patients before and after treatment. Ten of 14 hyperthyroid patients...Full Text Available
As for surface treatment of steel, the ion nitriding method has a lot of advantages and is practically used, while the plasma nitriding is known as a method which is faster in nitriding than the ion nitriding method. However, there are few reports and many unclear points on the plasma nitriding method. In this study, the plasma nitriding of pure iron and SUS304 is conducted using r.f. nitrogen plasma glow discharge to examine composition of the nitrided layers, microstructures, nitriding rate, etc. Moreover, by exposing the specimen once nitrided to H2 plasma, a phenomenon that nitrogen comes out of the specimen surface is examined. It is found from the result that the nitrided layer is divided into a compound layer and a diffusion layer in order from the surface, that in case of pure iron, the compound layer grows predominantly at a low temperature, and the diffusion layer grows ...
Plasma nitriding in glow discharge is a process of modifying surface properties of a material by which surface hardness, corrosion resistance, fatigue strength etc. of a material can be improved
1 Measuring total plasma levels of disopyramide (DP) and the main metabolite mono-N-dealkyldisopyramide (MND) in patients on maintenance therapy with DP has shown concentrations of MND comparable with...Full Text Available
A dielectric liquid having entrained bubbles of gas or vapor is subjected to an electric field applied between spaced electrodes (112, 116) which generates microdischarges (and thus plasma) within the bubbles, allowing modification of the properties of th...
The Plasma Science Committee (PLSC) of the National Research Council (NRC) is charged with monitoring the health of the field of plasma science in the United States and identifies and examines both broad and specific issues affecting the field. Regular meetings, teleconferences, briefings from agencies and the scientific community, the formation of study panels to prepare reports, and special symposia are among the mechanisms used by the PLSC to meet its charge. During July 1992, the PLSC sponsored a workshop on nonneutral plasmas in traps. Although no written report on the workshop results, was prepared for public distribution, a summary of highlights was provided to the OPST Subpanel on Nonneutral Plasmas. The PLSC also continued its follow-up briefings and discussions on the results of the results of the report Plasma Processing of materials. Scientific and Technological ...
The Plasma Science Committee (PLSC) of the National Research Council (NRC) is charged with monitoring the health of the field of plasma science in the United States and identifies and examines both broad and specific issues affecting the field. Regular meetings, teleconferences, briefings from agencies and the scientific community, the formation of study panels to prepare reports, and special symposia are among the mechanisms used by the PLSC to meet its charge. During July 1992, the PLSC sponsored a workshop on nonneutral plasmas in traps. Although no written report on the workshop results, was prepared for public distribution, a summary of highlights was provided to the OPST Subpanel on Nonneutral Plasmas. The PLSC also continued its follow-up briefings and discussions on the results of the results of the report Plasma Processing of materials. Scientific and Technological ...
Plasma exchange (PE) is currently being used to treat a variety of disorders involving immune complexes, such as polyarteritis nodosa. This procedure removes endogenous toxic components that accumulate...Full Text Available
Copper deficiency lowers brain copper and iron during development. The reduced iron content could be due to hypoferremia. Experiments were conducted to evaluate plasma iron and “ferroxidase”...Full Text Available
For supersonic plasma flow velocities, instead of the usual shelf-step profile seen for subsonic flow, an overdense bump and cavity is observed. The profile is stable for long times even for moderate power microwaves.
BackgroundHerpes simplex virus (HSV) suppressive therapy reduces genital and plasma HIV-1 RNA over periods up to three months but the longer-term effect is unknown.Full Text Available
An in vitro assay for curative antibody present in plasma of mice cured of Trypanosoma musculi is described. The assay involves the addition of plasma to a sample of infected blood, followed by hourly...Full Text Available
In this paper, we report on a series of experiments designed to study the influence of plasma nitriding on the mechanical properties of austenitic stainless steel. Plasma nitriding experiments were conducted on AISI 304L steel in a temperature range of 375-475 C using pulsed-DC plasma with different N{sub 2}-H{sub 2} gas mixtures and treatment times. Firstly the formation and the microstructure of the modified layer will be highlighted followed by the results of hardness measurement, adhesion testing, wear resistance and fatigue life tests. The modified surface was analyzed directly after plasma nitriding as well as using a depth profiling method. The microhardness after plasma nitriding is increased up to 19 GPa, that is a factor of five higher compared to the untreated material (3.3 GPa). The adhesion is examined by Rockwell indentation and scratch test. No delamination of the ...
The present article studies the electret state of polymers when moving through an alternating-current corona discharge plasma and investigates means for the determination of the transition of the polymeric material from the initial state of the electret when the corona-displaying voltage is increased.
Eight of 100 normotensive children who had pyelonephritic scarring secondary to urinary infection and vesicoureteric reflux were found in an earlier study to have increased plasma renin activity (PRA)....Full Text Available
During antibiotic drug development, media are frequently spiked with either serum/plasma or protein supplements to evaluate the effect of protein binding. Usually, previously reported serum or plasma...Full Text Available
A photon-induced x-ray fluorescence method allowing the simultaneous determination of iron, copper, zinc, bromine and rubidium in human blood and blood plasma samples is described. The method is reliable and has a good sensitivity for a wide range of elements. (author).
In this work, the Calibration-Free approach for Laser-Induced Breakdown Spectroscopy (CF-LIBS) was applied for the first time to radially resolved spectra emitted by a laser-induced plasma. The radial profiles of plasma temperature and electron number density were used to calculate the local relative concentration of the elements of interest. We analyzed a set of profiles of the local spectral emission coefficient obtained previously by means of spatial deconvolution of the spectra from a copper-based alloy (Cu 93, Fe 5, Mn 1, Ni 1 wt.%) laser-induced plasma. A spatially integrated spectrum of the same plasma was also analyzed for comparison purpose. The relative abundance of the minor components Fe, Mn and Ni was calculated. The results obtained from the central region of the plasma were closer to the nominal concentrations than those obtained from the spatially integrated ...
In this work, the Calibration-Free approach for Laser-Induced Breakdown Spectroscopy (CF-LIBS) was applied for the first time to radially resolved spectra emitted by a laser-induced plasma. The radial profiles of plasma temperature and electron number density were used to calculate the local relative concentration of the elements of interest. We analyzed a set of profiles of the local spectral emission coefficient obtained previously by means of spatial deconvolution of the spectra from a copper-based alloy (Cu 93, Fe 5, Mn 1, Ni 1 wt.%) laser-induced plasma. A spatially integrated spectrum of the same plasma was also analyzed for comparison purpose. The relative abundance of the minor components Fe, Mn and Ni was calculated. The results obtained from the central region of the plasma were closer to the nominal concentrations than those obtained from the spatially integrated ...
BACKGROUND AND OBJECTIVE:For treatment of benign prostatic hyperplasia (BPH), Plasma Kinetic loop Resection of the Prostate (PKRP) is an alternative to conventional monopolar...Full Text Available
Computational fluid dynamics are applied to the study of three-dimensional fluid flow in a dense medium plasma reactor (DMPR) under different operating conditions. Reaction mechanisms and rates for the removal of methyl t-butyl ether (MTBE) in a DMPR are developed from experimental data to determine the plasma volume, the rate of interphase mass transfer and the photolysis rate of MTBE via UV emission from the plasma. The simulations utilize the plasma volume determined from the kinetic data to show that the volume of fluid in contact with the plasma in the DMPR only constitutes a maximum of approximately 10% of the fluid intended to be cycled through the plasma tubules. The simulations also predict appreciable pressure gradients on the surface of the pin electrodes, resulting in a small discharge area located away from the region in which the electric field ...
This paper reports on the electron current to a Langmuir probe in a moving high-pressure plasma. The plasma is an atmospheric-pressure propane flame, and the probe's speed relative to the plasma is varied from 10 to 30 ms"-"1. The current is linearly dependent on the speed and appears to be comprised of two components - one driven by diffusion and the other by convection. A model is devised which can be used to measure the electron density. By comparing the density computed from this model to that measured from the ion current, it has been possible to measure the electron mobility in the flame gases. The value obtained here is in good agreement with theoretical calculations found in the literature.
Recent results of the experiments at GOL-3 facility are presented. Plasma with a density of 1014...1016 cm-3 is confined in a 12-meter-long solenoid, which comprises 55 corrugation cells with mirror ratio Bmax/B min=4.8/3.2 T. The plasma is heated up to 2...4 keV temperature by a high power relativistic electron beam (?1 MeV, ? 330 kA, ?8?s, ?120 kJ) injected through one of the ends. Mechanism of experimentally observed fast ion heating, issued of plasma stability and confinement are discussed.
The sheath plasma characteristics changing with the negative bias applied to the substrate during electron cyclotron resonance plasma nitriding are studied. The sheath characteristics obtained by a Langmuir single probe and an ion energy analyzer show that when the negative bias applied to the substrate is increasing, the most probable energy of ions in the sheath and the full width of half maximum of ions energy distribution increase, the thickness of the sheath also increases, whereas the saturation current of ion decreases. It has been found from the optical emission spectrum that there are strong lines of N_2 and N_2"+. Based on the experiment results the mechanism of plasma nitriding is discussed
Surface probe and laser-induced fluorescence measurements in ISX-B and EBT-S have made significant contributions to the understanding of plasma edge characteristics and plasma-surface interactions in these devices. Where comparison is possible, these techniques have led to results which are consistent with plasma diagnostics. Charge-exchange neutral sputtering and self-ion sputtering have been identified as the dominent heavy impurity release mechanisms in ISX-B and EBT-S, respectively.
Atmospheric pressure plasma enhanced chemical vapour deposition system is built. The electrical and optical characteristics of the APPECVD system is given. The system is used to deposit conductive polymers and nano composites onto glass and metal surfaces. The morphological, optical, chemical and electrical characteristics of deposited surfaces are investigated using SEM, AFM four probe deposition purposes. The photovoltaic applications of plasma deposited polymers and nonconsumption are compared with deposited with electrochemical methods show different results. The electrical, chemical and morphological structures of the samples will be given.
Closing and breaking of current in microsecond megaampere plasma opening switches are considered. Conductivity current scaling in the switch due to plasma acceleration by a magnetic piston is discussed and compared with experimental data. Two ways of determining the width of a current channel are taken up. This channel results from the diffusion of the magnetic field in the plane of the piston followed by the convective ejection of the field frozen in the accelerated plasma flow behind the shock wave into the bridge. Based on experimental data, a scaling law for the voltage on the switch according to the switch parameters is derived. The problem of reverse closing, which limits the efficiency of storage energy extraction into the load, is considered
Non-thermal plasma treatment is a promising technique for the destruction of volatile organic compounds in waste gas. A relatively unexplored technique is the atmospheric negative dc multi-pin-to-plate glow discharge. This paper reports experimental results of allyl alcohol degradation and ozone production in this type of plasma. A new model was developed to describe these processes quantitatively. The model contains a detailed chemical degradation scheme, and describes the physics of the plasma by assuming that the fraction of electrons that takes part in chemical reactions is an exponential function of the reduced field. The model captured the experimental kinetic data to less than 2 ppm standard deviation.
The ionization, excitation, and radiative recombination rates for highly stripped ions are cal- culated with Maxwellian and non-Maxwellian electron distribution functions of the type Cmexp(-vm/wm) (2<=m<=5) as encountered in laser-heated plasmas and certain types of turbulent plasmas. The direct-radiative-recombination rates are found to decrease by at most 30% as m is increased from 2 to 5. On the other hand, the ionization and excitation rates are found to be strongly reduced if the transition energy ? exceeds twice the local temperature kBTe. The effect of this on the distribution of energy levels and degrees of ionization in laser-produced plasmas could be important.
The hot uniform aluminium plasma was produced by irradiating thin aluminium dotted foil smoothly with the 9th 0.53 ?m laser on Shenguang II laser facility. The emitted spectrum was measured from the front and tangential direction of the target with two crystal spectrometers, and the quantitative spectrum from the front of the target was obtained. The state of laser- produced plasma was simulated with the radiation hydrodynamics code MULTI-1D, and the emitted spectrum was calculated with the spectrum code of Collision-Radiation model under the simulated plasma state. The experimental spectrum accords with the simulated one. (authors)
Measurements of the expansion rate of pure-electron plasmas have been performed on the Electron Diffusion Gauge (EDG) device at background helium gas pressures in the 5 x 10(superscript -8) Torr to 1 x 10(superscript -5) Torr range, where plasma expansion due to electron-neutral collisions dominates over plasma expansion due to trap asymmetries. It is found that the expansion rate, defined as the time rate of change of the particles' mean-square radius, scales approximately linearly with pressure and inversely as the square of the magnetic field strength in this regime, in agreement with classical predictions.
A clear and reproducible transition to a regime with an improved particle confinement is routinely observed on the CASTOR tokamak, if the biasing electrode is inserted deep enough into the plasma (r/a?0.5) and biased up to +250 V. The steepening of the radial profiles of the plasma density and potential demonstrate the formation of a transport barrier just inside the last closed flux surface. Fast relaxations of the edge plasma parameters, with a frequency of about 10 kHz, are observed when the average radial electric field within the barrier prevails values of about 20 kV/m. A detailed analysis of the spatial-temporal behaviour of these relaxations is presented.
We develop a new cavity with a mode similar to TE13 to produce microwave plasma, named APMPS II, which is able to produce a mass of air plasma with diameter of around 6 cm, equipped with about 3 kW input power under one atmosphere. The plasma seems to be homogeneous without significant filamentous discharge as observed by common camera device. We present the theory of this cavity, show the distribution of electric field of several planes inside the cavity and give some experimental results. (authors)
Properties of the multi-species electromagnetic Weibel and electrostatic two-stream instabilities are investigated for an intense ion beam propagating through background plasma. Assuming that the background plasma electrons provide complete charge and current neutralization, detailed linear stability properties are calculated within the framework of a macroscopic cold-fluid model for a wide range of system parameters.
Surface deposition probe techniques have been shown to be an effective means of determining the characteristics of the plasma edge region of magnetic confinement devices. Experimental results on ISX-B and EBT-S have led to a consistent picture of the edge plasma and the dominant impurity introduction mechanisms. This picture is supported by numerous other measurements and emphasizes the importance of concentrating several techniques on the complex problems of plasma fusion.
Complimentary spectroscopic, microscopic and electrochemical studies were performed to characterise the barrier properties as well as the interface structure of model iron substrates covered with thin plasma polymer films. Cathodic plasma polymers were deposited which show high barrier properties. The metal surface was pre-treated by a reducing or oxidising plasma. This allowed the adjustment of the oxidation state of the interface layer. The interface structure was characterised by means of X-ray photoelectron sputter profiles, infrared spectroscopy and the application of a Kelvin probe. The investigations show that the measured Voltapotential on the plasma polymer surface can be correlated with the oxidation state of the interface. Reducing plasmas lead to an almost oxide free surface. After deposition of the plasma polymer, this reduced state of the oxide is ...
Three dimensional rotatory modes of oscillations in a one-dimensional chain of rodlike charged particles or dust grains in a plasma are investigated. The dispersion characteristics of the modes are analyzed. The stability of different equilibrium orientations of the rods, phase transitions between the different equilibria, and a critical dependence on the relative strength of the confining potential are analyzed. The relations of these processes with liquid crystals, nanotubing, and plasma coating are discussed.
An intermetallic compound Sm[sub 2]Fe[sub 17]N[sub x] was synthesized by plasma nitriding of Sm[sub 2]Fe[sub 17] in a stream of N[sub 2]-H[sub 2] mixed gas. The reaction proceeded at a lower temperature (around 423 K) than that of the conventional thermal technique, but not at room temperature. This is discussed on the basis of the difference between the reaction mechanisms of plasma and thermal nitridings. (orig.)
We have investigated the effect of plasma nitriding and plasma nitrocarburizing on the microstructure and properties of electroplated chromium. Plasma nitriding and plasma nitrocarburizing are applied to 15-100 [mu]m thick electroplated hard chromium coatings to increase both the wear and the corrosion resistance. The properties of the plasma-modified hard chromium layers are characterized by measuring the wear resistance with a Taber wear tester and the corrosion resistance with a salt spray fog test. Cyclic voltammetry is performed in a standard electrochemical cell using a 0.5 M H[sub 2]SO[sub 4] solution acidified to pH 0.3. The compound layer after plasma nitriding consists of CrN and Cr[sub 2]N with a maximum hardness of about 1100 HK[sub 0.01]. After plasma nitrocarburizing, Cr[sub 3]C[sub 2] and Cr[sub 7]C[sub 3] are formed. After ...
Field reversed configuration (FRC) is a prospective high ? magnetic system for high efficiency D- 3He fusion reactor. Self-consistent FRC plasma profiles and static electric field for reactor calculations are discussed in framework of the model including flow equilibrium and collisionless transport equations. The extrapolations to reactor regimes of plasma confinement scaling laws are considered.
The qualitative technique of the analysis of the efficiency of the RF plasma production is presented in which the solution of boundary problem for Maxwell's equations is only necessary. The analysis of the character of the plasma production process with the crankshaft antenna in Uragan-2M stellarator is carried out. The discussion of the calculations results is presented.
The importance of neutron measurements both as a succinct measure of the progress to fusion ignition using the magnetic confinement route and also as a diagnostic of plasma conditions is discussed. The various neutron diagnostic systems that have been or are being constructed by AERE Harwell for JET are described. The properties to be measured by such diagnostics are clearly identified and some results obtained with the installed diagnostics during d-d plasmas are presented.
Plasma confinement by permanent magnets has been studied. An analytic formula for the field of a single bar magnet has been obtained. Generalization to various configurations of multidipole fields has also been found. Any two-dimensional field may now be completely described by a simple function of complex variables in closed form. Vector potential has also been obtained by integrating over a prescribed Riemann surface. The confinement of plasma by multidipole fields then becomes obvious through conservation principles.
A two-beam spectroscopy (TBS) system is evaluated theoretically and experimentally. This new spectroscopic technique uses correlations between components of emitted light separated by a small difference in angle of propagation. It is thus a non-perturbing plasma diagnostic which is shown to provide local (as opposed to line-of-sight averaged) information about fluctuations in the density of light sources within a plasma - information not obtainable by the usual spectroscopic methods. The present design is an improvement on earlier systems proposed in a thesis by Rostler.
Electromagnetic effects excited by intense relativistic electron beams in plasmas are investigated using a two-dimensional particle code. The simulations with dense beams show large magnetic fields excited by the Weibel instability as well as sizeable electromagnetic radiation over a significant range of frequencies. The possible relevance of beam plasma instabilities to the laser acceleration of particles is briefly discussed. 6 refs., 4 figs.
The thermo-chemical treatments of steels with plasma is normally carried out in low-pressure ionized gaseous atmospheres. Among the treatments used most often are: nitruration, carburization and boronized. A plasma can also generate at atmospheric pressure. One way to produce it is with an electrochemical cell that works at a relatively high inter-electrode voltage and under conditions of heavy gas generation. This type of plasma is known as electrolytic plasma. This work studies the feasibility of using electrolytic plasma for the surface processing of steels. Two processes were selected: boronized and nitruration., for the hardening of two types of steel: one with low carbon (1020) and one with low alloy (4140). In the case of the nitruration, the 1020 steel was first aluminized. The electrolytes were aqueous solutions of borax for the boronizing and urea for the nitruration. The ...
The fundamental ionisation process of negative surface ionisation is described and two applications are discussed. One is in the so called surface-plasma sources which enable the production of intense negative ion beams. The second application is in the passive diagnosis of the charge exchange of neutrals emitted from hydrogen plasmas.
Although silicosis has been studied extensively, the mechanism is still not fully understood. Experiments do provide evidence that the actions of unique properties of silica surface on the cell membrane are the starting point of silicotic processes. This paper summarizes literature on chemical properties of silica surface, and the effect of particle size on silica toxicity. This paper also discusses the ways in which silica dusts are though to interact with the cell membrane, with emphasis on freshness, hydrogen bonding, and free-radical interactions.
Biological motors generally fall into two categories: (1) those that convert chemical into mechanical energy via hydrolysis of a nucleoside triphosphate, usually adenosine triphosphate, regarded as life's chemical currency of energy and (2) membrane bound motors driven directly by an ion gradient and/or membrane potential. Here we argue that electrostatic interactions play a vital role for both types of motors and, therefore, the tools of physics can greatly contribute to understanding biological motors.
French ... Title Synthese d'agregats metalliques par radiolyse de solutions aqueuses de sels simples ou complexes. Etude par M. E. du greffage des agregats sur membranes de carbone.
Two different reverse osmosis systems were investigated. The first was a 50-element plant-scale system that is used to treat 2200 m"3 of AECL liquid radwastes annually.It uses thin-film composite (TFC) membranes and operates at an applied pressure of 2760 kPa, with a fixed crossflow of about 40 L/min. The other system uses the same thin-film composite membranes for waste processing but is a two-element pilot-scale system. It is operated at pressures m ranging between 1500 and 7000 kPa, at a fixed crossflow of 55 L/min. The average lifetime of the thin-film composite membranes in the plant-scale processing application at AECL is about 3000 h. After this service life has expired the rejection efficiency declines rapidly from 99.5% to about 95% as the membranes become impaired from chemical cleaning procedures that are required after each 100 m"3 of waste is treated. The permeation flux for the plant-scale ...
An enzyme-linked immunosorbent assay was used to compare Brucella melitensis major outer membrane proteins (MOMP) and whole-cell heat-killed antigens (HK) in measuring antibrucella immunoglobulin G...Full Text Available
During apoptosis, the pro-apoptotic Bcl-2 family proteins BAK and BAX form large oligomeric pores in the mitochondrial outer membrane. Apoptotic factors, including cytochrome c, are...Full Text Available
The serpin ZPI is a protein Z (PZ)-dependent specific inhibitor of membrane-associated factor Xa (fXa) despite having an unfavorable P1 Tyr. PZ accelerates the inhibition reaction ∼2000-fold...Full Text Available
Non-thermal (low-temperature) physical plasma is under intensive study as an alternative approach to control superficial wound and skin infections when the effectiveness of chemical agents is weak due to natural pathogen or biofilm resistance. The purpose of this study was to test the individual susceptibility of pathogenic bacteria to non-thermal argon plasma and to measure the effectiveness of plasma treatments against bacteria in biofilms and on wound surfaces. Overall, Gram-negative bacteria were more susceptible to plasma treatment than Gram-positive bacteria. For the Gram-negative bacteria Pseudomonas aeruginosa, Burkholderia cenocepacia and Escherichia coli, there were no survivors among the initial 10(5) c.f.u. after a 5 min plasma treatment. The susceptibility of Gram-positive bacteria was species- and strain-specific. Streptococcus pyogenes was the most resistant with 17?% ...
The goal of the present study is to elucidate the effect of lipid domain formation on activities of Naja naja atra and Bungarus multicinctus phospholipase A(2) (PLA(2)) enzymes. Sphingomyelin inhibited enzymatic activity and membrane-damaging activity of PLA(2) against egg yolk phosphatidylcholine (EYPC), while cholesterol and cholesterol sulfate abrogated the inhibitory effect of sphingomyelin. The ability of cholesterol and cholesterol sulfate to abolish the inhibitory effect of sphingomyelin was closely related to their capacity to induce domain formation in EYPC/sphingomyelin vesicles. Laurdan fluorescence measurement revealed that membrane packing of EYPC/sphingomyelin vesicles was differently affected by cholesterol and cholesterol sulfate. Unlike cholesterol, cholesterol sulfate was unable to promote domain formation in dipalmitoylphosphatidylcholine (DPPC) vesicles. Cholesterol increased but cholesterol sulfate reduced PLA(2) activity ...
This study examined the oxygen permeation behavior of Ce0.9Gd0.1O2-d (Gadolinium-Doped Ceria, GDC)/Ba0.5Sr0.5Co0.8Fe0.2O3-d (BSCF) composite membranes fabricated using a conventional sintering technique. GDC/BSCF composite membranes with a relative density >95% could be obtained when a green compact of BSCF and GDC was sintered at 1150^oC for 5h. It appears that GDC serves as a grain growth inhibitor because the average grain size of the composite decreased with increasing GDC content. The oxygen permeability of the BSCF and GDC/BSCF composite membranes strongly depends on the grain size and membrane thickness. The addition of GDC to BSCF resulted in a small grain size, low thermal expansion coefficient and high hardness. However, it is believed that oxygen permeation was blocked by GDC, a...
A new organic-inorganic hybrid membrane has been prepared with exceptional performance in dewatering applications. The only precursor used in the sol-gel synthesis of the selective layer was organically linked 1,2-bis(triethoxysilyl)ethane (BTESE). The microporous structure of this layer enables selective molecular sieving of small molecules from larger ones. In the dehydration of n-butanol with 5% of water, the membrane shows a high separation factor of over 4000 and ultra-fast water transport at a rate of more than 20 kg m{sup -2} h{sup -1} at 150C. This can be related to the high adsorption capacity of the material and the sub-micron thickness of the selective layer. The selectivity has now remained constant over almost one and a half years under continuous process testing conditions. Apart from the hydrothermal stability, the membrane exhibits a high tolerance for acid contamination. A slow performance decline in flux ...
The soluble pool of alpha hemoglobin chains present in blood or bone marrow cells was measured with a new affinity method using a specific probe, beta A hemoglobin chain labeled with ["3H]N-ethylmaleimide. This pool of soluble alpha chains was 0.067 #+-# 0.017% of hemoglobin in blood of normal adult, 0.11 #+-# 0.03% in heterozygous beta thalassemia and ranged from 0.26 to 1.30% in homozygous beta thalassemia intermedia. This elevated pool of soluble alpha chains observed in human beta thalassemia intermedia decreased 33-fold from a value of 10% of total hemoglobin in bone marrow cells to 0.3% in the most dense red blood cells. The amount of insoluble alpha chains was measured by using the polyacrylamide gel electrophoresis in urea and Triton X-100. In beta thalassemia intermedia the amount of insoluble alpha chains was correlated with the decreased spectrin content of red cell membrane and was associated with a decrease in ankyrin and with other abnormalities of ...
The authors address the question of the limitations on voltage and current transfer to loads in magnetic storage systems utilizing microsecond conduction time plasma opening switches. They propose that the limitation of performance results from neutral atoms that are not entrained into the ionized material that is driven by the magnetic field of the rising generator current. Evidence in support of this proposition is gathered from experiments performed on the Ace-4 and Hawk generators. They set forth a theory to describe the effect of neutrals on the electrical performance of plasma opening switches. The neutral gas is assumed to be present in the region between the moving plasma mass and the generator, primarily in the region in which the plasma is injected initially. The essential elements of the theory are a weak photoionization source to seed the gas with a low concentration of electrons, and joule ...
We have studied the features of formation and the possible stationary structures of a self-consistent magnetic field in a relativistic collisionless plasma, which are characteristic of a simple geometry of the Weibel instability that is well known in the nonrelativistic case. The universal condition is established, the growth rate is determined, and the criteria of saturation of the Weibel instability are analyzed for a broad class of anisotropic particle distribution functions (for definiteness, in application to an electron-positron plasma). A nonlinear equation of the Grad-Shafranov type describing the potential current structures is derived and its solutions are analytically studied. Special attention is paid to spatially harmonic, nonlinear current configurations with parameters determined by the properties of the initial homogeneous plasma subject to the Weibel instability. It is demonstrated that the magnetic field ...
To clarify the mechanism of plasma nitriding, the authors examined the optical microstructure, the hardness, the precipitation, and the concentration of dissolved nitrogen in Fe-18Cr-9Ni nitrided using plasma in the range of 723-823 K. Compared with ammonia-gas nitriding, the features of plasma nitriding are the formation of small chromium-nitride precipitates (CrN), the absence of an externally nitrided layer, the high concentration of dissolved nitrogen, and the high hardness (HV = 1,200). The diffusion coefficient of nitrogen in the present alloy was determined using the growth rate of the internally nitrided layer, based on calculations used in internal oxidation. Plasma- and gas-nitriding were also compared with respect to the growth rate of the nitrided layer.
In this paper we study theoretically a pulsed corona discharge plasma in air at atmospheric pressure. A self consistent one-dimensional model, using a flux-corrected transport numerical scheme, is presented to achieve it. The charged particle kinetics in this model are described by one-dimensional continuity equations coupled with Poisson's equations. The spatio-temporal local field, charge density variations and the velocity profile of an ionizing front are calculated to describe the dynamical behavior of corona discharge plasmas. The simulation results of a wire-in-cylinder corona discharge plasma explain the physical mechanisms of discharge processes. These results may also be apply to obtain the optimizing parameters for designing the plasma reactor.
The physics of density limit phenomena in toroidal helical plasmas based on an analytic point model of toroidal plasmas is discussed. The combined mechanism of the transport and radiation loss of energy is analyzed, and the achievable density is derived. A scaling law of the density limit is discussed. The dependence of the critical density on the heating power, magnetic field, plasma size and safety factor in the case of L-mode energy confinement is explained. The dynamic evolution of the plasma energy and radiation loss is discussed. Assuming a simple model of density evolution, of a sudden loss of density if the temperature becomes lower than critical value, then a limit cycle oscillation is shown to occur. A condition that divides the limit cycle oscillation and the complete radiation collapse is discussed. This model seems to explain the density limit oscillation that has been observed on the W7-AS ...
The present conference discusses plasma-assisted surface coating/modification processes, the applications to date of ion nitriding, the effects of nitrogen on metal surfaces, ion nitriding mechanisms in Cr, Al and Cr + Al-containing 1040 steel, ion nitriding of Al and its alloys, life enhancement for forging dies, novel anode plasma nitriding developments, and a comparative study of the pulsed and dc ion-nitriding behavior in specimens with blind holes. Also discussed are the influence of heating method on ion nitriding, surface hardening of marage steels by ion nitriding without core hardness reduction, plasma nitriding of nodular cast iron sput gears, NbN composites for superconductors, the carburization of tungsten in a glow discharge methane plasma, economic considerations concerning plasma nitriding, and the corrosion properties obtained by ion nitriding.
Interest in the tribological properties of plasma nitriding has increased substantially over the past years because plasma nitriding provides a high nitride depth and improved hard facing. The present study examines the tribological properties of AISI H11 plasma nitrided, hot-worked steel. Different nitriding temperatures and durations were considered. Characterization of the composite structures was investigated with wear tests, x-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), and microhardness tests. The depth profile of the nitrided zone was measured using the nuclear reaction analysis (NRA) technique. Plasma nitriding affected the microhardness, wear properties, and morphology considerably. Increase in process temperature increased the nitride zone depth.
We report on the formation of current blocking regions by O2 plasma treatment to reduce current crowding at the active region above the p-type electrodes of GaN-based vertical light emitting diodes (LEDs). The forward voltage and reverse current (at -5 V) of the plasma-treated LEDs slightly increase with increasing aging time. The output power (at 350 mA) of the plasma-treated LEDs is enhanced by 26% as compared to that of reference LEDs and is comparable to that of LEDs with SiO2 current blocking layers. It is shown that the output power (at 700 mA) of the plasma-treated LEDs is degraded by less than 2% of the initial value after 500 h.
The combined process of low temperature plasma nitriding and TiN film deposition was realized on the plasma-assisted vacuum arc plating set. The process of plasma nitriding can be done below 200 degree C. The low temperature plasma nitriding and TiN film deposition was realized on the same device. By the SEM analysis of the plating structure, low hardness grads from the substrate to the film was obtained, and it was found that the mixed nitride plating formed at the interface between the substrate and the film. The quantitative measurement of substrate-film adherence showed that the adherence was improved notably by using the process. The adherence between film and substrate can reach to 59.6 MPa without the bias voltage supplying
In this work AISI 1045 steel were duplex treated via plasma nitriding of chromized layer. Samples were pack chromized by using a powder mixture consisting of ferrochromium, ammonium chloride and alumina at 1273K for 5h. The samples were then plasma-nitrided for 5h at 803K and 823K, in a gas mixture of 75%N2+25%H2. The treated specimens were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis and Vickers micro-hardness test. The thickness of chromized layer before nitriding was about 8mm and it was increased after plasma nitriding. According to XRD analysis, the chromized layer was composed of chromium and iron carbides. Plasma nitriding of chromized layer resulted in the formation of chromium and iron nitrides and carbides. The hardness of the duplex layer...
We present and characterize a very efficient optical device that employs the plasma mirror technique to increase the contrast of high-power laser systems. Contrast improvements higher than 104 with 50% transmission are shown to be routinely achieved on a typical 10 TW laser system when the pulse is reflected on two consecutive plasma mirrors. Used at the end of the laser system, this double plasma mirror preserves the spatial profile of the initial beam, is unaffected by shot-to-shot fluctuations, and is suitable for most high peak power laser systems. We use the generation of high-order harmonics as an effective test for the contrast improvement produced by the double plasma mirrors. (authors)
Plasma Technologies in Institute of Plasma Physics of the NSC KIPT are recently developed in the following directions. Material surfaces modification under their irradiation with pulsed plasma streams of different working gases. Besides traditional analysis of improvements of tribological characteristics and structural-phase changes of the modified layers recently we started investigations of material corrosions characteristic improvement under influence of pulsed plasma on the material surfaces. As to the surface coatings in arc discharges of Bulat type devices, new trends are related with multi-layers coatings, using Ti-AI-N coatings in cutting tools, using high frequency discharges or combined HF- and arc discharges for increasing the nomenclature of goods to be coated. Development of ozonators is respectively new area for IPP NSC KIPT. On the base of barrier high-frequency discharge there were ...
Plastic composites have become a large class of construction material for exterior applications. One of the main disadvantages of wood plastic composites resides in the weak adhesion between the polar and hydrophilic surface of wood and the non-polar and hydrophobic polyolefin matrix, hindering the dispersion of the flour in the polymer matrix. To improve interfacial compatibility wood flour can be pretreated with environmentally friendly methods such as cold-atmospheric pressure plasma. The objective of this work is therefore to evaluate the potential of plasma polymerization of acetylene on wood flour to improve the compatibility with polyolefins. This presentation will describe the reactor design used to modify wood flour using acetylene plasma polymerization. The optimum conditions for plasma polymerization on wood particles will also be presented. Finally preliminary results on the wood flour ...
Hydrogen (H) plasma treatment, oxygen (O) plasma treatment and water (H_2O)-vapor heat treatment for polycrystalline-silicon (poly-Si) thin-film transistors (TFTs) have been analyzed by separately extracting trap density at a front silicon-oxide interface (D_F) and trap density at a back interface (D_B). It is found that the H plasma treatment is apt to generate D_F and D_B. The O plasma treatment reduces D_F, while the H_2O-vapor heat treatment reduces both D_F and D_B. Improvement of transistor characteristics of poly-Si TFTs depends on understanding these results.
We use a massively parallel 3D hybrid particle code, dHybrid, to simulate the deflection of plasma beams by a dipole like magnetic field in a laboratory environment. Dipole magnetic fields, along with a plasma injection source to inflate the magnetic field, are now being studied as means of deflecting solar wind and Energetic Particles away from spacecrafts [1,2,3]. We have considered three setups, consistent with the experiments, with a plasma beam fired at i) a dipole field with no plasma injection, ii) a plasma injection source with no dipole field and iii) a dipole field with a plasma injection source. The hybrid simulations help understand the relevant physical phenomena, and enable extrapolation to space plasma scenarios, where setups are similar but plasma parameters differ significantly. The simulation results ...
A theoretical model is presented to describe the electromagnetic, heat transfer and fluid flow phenomena within a magnetron plasma torch and in the resultant plume, by using a commercial computational fluid dynamics (CFD) code FLUENT. Specific calculations are presented for a pure argon system (i.e., an argon plasma discharging into an argon environment), operated in a turbulent mode. An important finding of this work is that the external axial magnetic field (AMF) may have a significant effect on the behavior of arc plasma and thus affects the resulting plume. The AMF impels the plasma to retract axially and expand radially. As a result, the plasma intensity distribution on the cross section of torch seems to be more uniform. Numerical results also show that with AMF, the highest plasma temperature decreases and the anode arc root moves upstream significantly, ...
Surface compositional changes in GaAs due to RF plasmas of different gases have been investigated by XPS and etch rates were measured using AFM. Angular Resolved XPS (ARXPS) was also employed for depth analysis of the composition of the surface layers. An important role in this study was determination of oxide thickness using XPS data. The study of surface - plasma interaction was undertaken by correlating results of surface analysis with plasma diagnosis. Different experiments were designed to accurately measure the BEs associated with the Ga 3d, Ga 2p sub 3 sub / sub 2 and LMM peaks using XPS analysis and propose identification in terms of the oxides of GaAs. Along with GaAs wafers, some reference compounds such as metallic Ga and Ga sub 2 O sub 3 powder were used. A separate study aiming the identification of the GaAs surface oxides formed on the GaAs surface during and after plasma processing was ...
By using a plasma nitriding procedure at the PUPR Mirror Cusp Plasma machine, surface hardness is increased in 302/304-type stainless steel samples by exposing them to high-ion-density plasma at high vacuum. This method successfully dopes the surface of the material with strengthening nitrogen ions, without the use of chemical procedures that sacrifice the resistance to corrosion of the given material. A 500 V negative bias is placed on the sample exposed to the nitrogen plasma, where high-energy ions are therefore attracted and immersed into the metallic matrix microns into the surface of the stainless steel. This potential maintains a constant surface temperature at approximately 800 deg. C. The plasma parameters including ion density and plasma temperature were diagnosed using single Langmuir probes. The stainless steel samples were then tested using scanning ...
By using a plasma nitriding procedure at the PUPR Mirror Cusp Plasma machine, surface hardness is increased in 302/304-type stainless steel samples by exposing them to high-ion-density plasma at high vacuum. This method successfully dopes the surface of the material with strengthening nitrogen ions, without the use of chemical procedures that sacrifice the resistance to corrosion of the given material. A 500 V negative bias is placed on the sample exposed to the nitrogen plasma, where high-energy ions are therefore attracted and immersed into the metallic matrix microns into the surface of the stainless steel. This potential maintains a constant surface temperature at approximately 800 deg. C. The plasma parameters including ion density and plasma temperature were diagnosed using single Langmuir probes. The stainless steel samples were then tested using scanning ...
Simultaneous nitriding and ageing heat treatments of precipitation hardenable tool steel was carried out inside a DC-pulsed plasma nitriding reactor. A single heat treatment cycle was done, as the plasma nitriding and age hardening processes occur approximately at the same ranges of temperatures and times. Specimens of Cr-Ni-Mo-Al age hardenable steel, in the solubilized and solubilized and aged conditions, were tested. Plasma nitriding and ageing, carried out at 500 deg. C for times ranging between 2 and 8 h, increased the surface hardness up to 1000 HV, producing case depths between 100 and 200 {mu}m. The core hardness of solubilized samples increased from 30 to 39 Rockwell C after the plasma nitriding treatment proving the possibility of nitriding and ageing at the same treatment cycle. The pre-aged samples did not show any overageing after the simultaneous plasma nitriding and ...
Simultaneous nitriding and ageing heat treatments of precipitation hardenable tool steel was carried out inside a DC-pulsed plasma nitriding reactor. A single heat treatment cycle was done, as the plasma nitriding and age hardening processes occur approximately at the same ranges of temperatures and times. Specimens of Cr-Ni-Mo-Al age hardenable steel, in the solubilized and solubilized and aged conditions, were tested. Plasma nitriding and ageing, carried out at 500 deg. C for times ranging between 2 and 8 h, increased the surface hardness up to 1000 HV, producing case depths between 100 and 200 #mu#m. The core hardness of solubilized samples increased from 30 to 39 Rockwell C after the plasma nitriding treatment proving the possibility of nitriding and ageing at the same treatment cycle. The pre-aged samples did not show any overageing after the simultaneous plasma nitriding and ...
Nitrogen ion implantation improves the wear resistance of Ti-6Al-4V alloys by forming a hard TiN superficial passivation layer. However, the thickness of the layer formed by traditional ion implantation is typically 100-200 nm and may not be adequate for many industrial applications. We propose to use radio-frequency (RF) plasma nitriding and nitrogen plasma immersion ion implantation (PIII) to increase the layer thickness. By using a newly designed inductively coupled RF plasma source and applying a series of negative high voltage pulses to the Ti-6Al-4V samples. RF plasma nitriding and nitrogen PIII can be achieved. Our process yields a substantially thicker modified layer exhibiting more superior wear resistance characteristics, as demonstrated by data from micro-hardness testing, pin-on-disc wear testing, scanning electron microscopy (SEM), as well as Auger electron spectroscopy (AES). The ...
Nitrogen ion implantation improves the wear resistance of Ti-6Al-4V alloys by forming a hard TiN superficial passivation layer. However, the thickness of the layer formed by traditional ion implantation is typically 100-200 nm and may not be adequate for many industrial applications. We propose to use radio-frequency (RF) plasma nitriding and nitrogen plasma immersion ion implantation (PIII) to increase the layer thickness. By using a newly designed inductively coupled RF plasma source and applying a series of negative high voltage pulses to the Ti-6Al-4V samples. RF plasma nitriding and nitrogen PIII can be achieved. Our process yields a substantially thicker modified layer exhibiting more superior wear resistance characteristics, as demonstrated by data from micro-hardness testing, pin-on-disc wear testing, scanning electron microscopy (SEM), as well as Auger electron spectroscopy (AES). The ...
Here we describe the use of low energy plasma immersion with active screen as a convenient approach for polypropylene (PP) surface modification. Employing a stainless steel cathodic cage coated with carbon in order to prevent the sputtering of iron from the grid and its deposition onto the polymer sample, the physical chemical properties of PP surface could be effectively modified through the plasma-induced incorporation/formation of nitrogen- and oxygen-containing species. The areal densities of these elements depended on the plasma excitation source, as determined by Rutherford backscattering spectrometry (RBS). Newly formed C-O, C-N, and C=O/O=C-O/N-C=O bonds along with C-C linkages from the PP backbone were identified at the near surface region of the specimens by X-ray photoelectron spectroscopy (XPS). The insertion of such polar reactive functionalities was further confirmed by a substantial decrease in the water ...
The phenomenology of wire chamber aging is discussed and fundamentals of proportional counters are presented. Free-radical polymerization and plasma polymerization are discussed. The chemistry of wire aging is reviewed. Similarities between wire chamber plasma (>1 atm dc-discharge) and low-pressure rf-discharge plasmas, which have been more widely studied, are suggested. Construction and use of a system to allow study of the plasma reactions occurring in wire chambers is reported. A proportional tube irradiated by an {sup 55}Fe source is used as a model wire chamber. Condensable species in the proportional tube effluent are concentrated in a cryotrap and analyzed by gas chromatography/mass spectrometry. Several different wire chamber gases (methane, argon/methane, ethane, argon/ethane, propane, argon/isobutane) are tested and their reaction products qualitatively identified. For all gases tested ...
Using the ammonia (NH3) plasma generated by a helical antenna surrounded by two magnetic coils, the transition of the discharge mode from low-density plasma to high-density one was observed. At the transition, the emission intensities from the H atoms and NH radicals especially increased in the optical emission spectroscopy, while the intensities of the other emission lines also increased abruptly. The nitridation of gallium arsenide (GaAs) surface was performed using the high-density NH3 plasma, and the properties of the nitrided surface layer were compared with those nitrided by high-density N2 plasma using the same apparatus. From the spectroscopic ellipsometry measurements, the thickness of the nitrided layer was estimated to be 16-18 nm, while that by N2 was 3-4 nm. From the Ga 3d spectra, the contamination with oxygen in the nitridation layer by NH3 plasma was less than that ...
The magnetically controlled plasma opening switch (MCPOS) is an advanced plasma opening switch that utilizes magnetic fields to improve operation. Magnetic fields always dominate terawatt, pulsed power plasma opening switches. For that reason, the MCPOS uses controlled applied magnetic fields with magnitude comparable to the self-magnetic field of the storage inductor. One applied field holds the plasma in place while energy accumulates in the storage inductor, then another applied field pushes the plasma away from the cathode to allow energy to flow downstream. Over a ten month period, an MCPOS was designed, built, and tested on DECADE Module 2 at Physics International. The peak drive current was 1.8 MA in 250 ns. The output parameters were up to 1 MA into an electron beam load. The radiation temporal pulse width averaged 60 nanoseconds full-width at half-maximum. The peak load ...
We have successfully incorporated high surface area particles of titanate ion exchange materials (monosodium titanate and crystalline silicotitanate) with acceptable particle size distribution into porous and inert support membrane fibrils consisting of polytetrafluoroethylene (Teflon(reg_sign)), polyethylene and cellulose materials. The resulting membrane sheets, under laboratory conditions, were used to evaluate the removal of surrogate radioactive materials for cesium-137 and strontium-90 from high caustic nuclear waste simulants. These membrane supports met the nominal requirement for nonchemical interaction with the embedded ion exchange materials and were porous enough to allow sufficient liquid flow. Some of this 47-mm size stamped out prototype titanium impregnated ion exchange membrane discs was found to remove more than 96% of dissolved cesium-133 and strontium-88 from a caustic nuclear waste ...
Plasma neutralization of an intense ion pulse is of interest for many applications, including plasma lenses, heavy ion fusion, cosmic ray propagation, etc. An analytical electron fluid model has been developed based on the assumption of long charge bunches (l{sub b} >> r{sub b}). Theoretical predictions are compared with the results of calculations utilizing a particle-in-cell (PIC) code. The cold electron fluid results agree well with the PIC simulations for ion beam propagation through a background plasma. The analytical predictions for the degree of ion beam charge and current neutralization also agree well with the results of the numerical simulations. The model predicts very good charge neutralization (>99%) during quasi-steady-state propagation, provided the beam pulse duration {tau}{sub b} is much longer than the electron plasma period 2{pi}/{omega}{sub p}, where {omega}{sub ...
Gyrokinetic particle simulation of edge pedestal formation and plasma rotation dynamics will be presented, and compared with experimental observations. Realistic tokamak edge geometry is used which include separatrix/X-point and material wall from EFIT g-eqdsk data. In order to handle adequately the spatially inhomogeneous electric potential in the scrape-off region, the full-f electron technique is used, in addition to the full-f ions. Monte Carlo neutral particles with wall recycling coefficient will be included self-consistently with the plasma kinetics. Ion-ion Coulomb collisions will be particle, momentum and energy conserving. Energy source for the pedestal and scrape-off plasmas is the heat flow from the core plasma, and the particle source is the ionization of the neutral atoms which are either wall recycled and/or gas puffed. The simulation will be self-consistent with the first principles ...
A study on oxygen-plasma treatment of ink-jet paper is presented. Paper was exposed to a weakly ionized, highly dissociated oxygen plasma with an electron temperature of 5 eV, a positive-ion density of 8 x 1015 m-3 and a density of neutral oxygen atoms of 5 x 1021 m-3. Optical emission spectroscopy (OES) was applied as a method for detection of the reaction products during the plasma treatment of the paper. OES spectra between 250 and 1000 nm were measured continuously during the plasma treatment. The wettability of the samples before and after the plasma treatment was determined by measuring the contact angle of a water drop. The appearance of the surface-functional groups was determined by using high-resolution x-ray photoelectron spectroscopy (XPS), while changes in the surface morphology were monitored with scanning electron microscopy (SEM). Already after 1 s of the ...
The WEGA stellarator is used to confine low temperature, overdense (densities exceeding the cut-off density of the heating wave) plasmas by magnetic fields in the range of B=50-500 mT. Microwave heating systems are used to ignite gas discharges using hydrogen, helium, neon or argon as working gases. The produced plasmas have been analyzed using Langmuir and emissive probes, a single-channel interferometer and ultra-high resolution Doppler spectroscopy. For a typical argon discharge in the low field operation, B=56 mT, the maximum electron density is n{sub e}{proportional_to}10{sup 18} m{sup -3} with temperatures in the range of T=4-12 eV. The plasma parameters are determined by using Langmuir probes and are cross-checked with interferometry. It is demonstrated within this work that the joint use of emissive probes and ultra-high resolution Doppler spectroscopy allows a precise measurement of the radial electric field. The ...
An original dc double anode plasma torch which provides a long-time and highly stable atmospheric plasma jet has been devised for the purpose of hazardous waste treatment. The arc fluctuations and dynamic behaviour of the argon and argon-nitrogen plasma jets under different operating conditions have been investigated by means of classical tools, such as the statistic method, fast Fourier transform (FFT) and correlation analysis. In our experiments, the takeover mode is identified as the fluctuation characteristic of the argon plasma jet while the restrike mode is typical in the argon-nitrogen plasma dynamic behaviour. In the case of pure argon, the FFT and correlation calculation results of electrical signals exhibit the only characteristic frequency of 150 Hz, which originates from the torch power and is independent of any change in the operating conditions. It indicates that the ...
Various kinds of decontaminations are carried out in atomic power plant. Here current decontamination technologies such as chemical decontamination with chemical solution or blast decontamination have a problem of reduction of secondary radioactive waste generated in the decontamination process. On the other hand, a low pressure arc plasma can remove metal oxide film on the metal substrate without heavy damage on the metal substrate when the object to be treated was set as a cathode. Dry surface decontamination technology with using low-pressure arc plasma can decrease secondary radioactive waste because low-pressure arc plasma does not need any chemical solution. In addition, the time required for treatment can be shorter, so it is possible for the low-pressure arc plasma decontamination technology to interpolate the current decontamination technologies such as spot decontamination technology etc. ...
Eugenol, the principal chemical component of clove oil from Eugenia aromatica has been long known for its analgesic, local anesthetic, anti-inflammatory, and antibacterial effects. The interaction of the eugenol with ten different hydrophobic and hydrophilic antibiotics was studied against five different Gram negative bacteria. The MIC of the combination was found to decrease by a factor of 5-1000 with respect to their individual MIC. This synergy is because of the membrane damaging nature of eugenol, where 1mM of its concentration is able to damage nearly 50% of the bacterial membrane. Eugenol was also able to enhance the activities of lysozyme, Triton X-100 and SDS in damaging the bacterial cell membrane. The hydrophilic antibiotics such as vancomycin and b-lactam antibiotics which have ...
Even the presence of very low concentrations of dyes (1mgL-1) in the effluent is highly visible and is considered aesthetically undesirable. It must be removed from wastewater completely. This study systematically evaluates the performance of adsorption (three kinds of powdered activated carbons), coagulation (AlCl36H2O) and membrane (submerged hollow fiber microfiltration) processes individually in treating two kinds of reactive dyes (Orange 16 and Black 5) and then using a hybrid process with combined coagulation-adsorption-membrane treatment system. Adsorption capacity and kinetics of Orange 16 were much higher and faster than those of Black 5. The dye removal efficiency by coagulation was highly dependent on dye concentration and solution pH. The hybrid process performance was far more...
A major goal in optomechanics is to observe and control quantum behavior in a system consisting of a mechanical resonator coupled to an optical cavity. Work towards this goal has focused on increasing the strength of the coupling between the mechanical and optical degrees of freedom; however, the form of this coupling is crucial in determining which phenomena can be observed in such a system. Here we demonstrate that avoided crossings in the spectrum of an optical cavity containing a flexible dielectric membrane allow us to realize several different forms of the optomechanical coupling. These include cavity detunings that are (to lowest order) linear, quadratic, or quartic in the membrane's displacement, and a cavity finesse that is linear in (or independent of) the membrane's displacement. All these couplings are realized in a single device with extremely low optical loss and can be tuned over a wide range in situ; in ...
Mechanistic studies on a charged ultrafiltration (UF) membrane fouled with natural organic matter (NOM) and colloidal particles are systematically investigated to understand the relative role of each NOM fraction and the presence of colloidal particulate to membrane fouling. Humic acid (HA), dextran, and kaolin were employed as surrogate model foulants representing the organic hydrophobic acid NOM, hydrophilic neutral NOM, and inorganic colloidal materials, respectively. The results obtained showed that the organic NOM of hydrophilic surrogate (dextran) plays a primary role in promoting membrane fouling, followed by hydrophobic acids and inorganic kaolin, but to a lesser extent than organic NOM compounds. Significant differences in the extent of fouling between dextran and HA have been obs...
We present a synchrotron x-ray diffraction study of melting in stacks of two-dimensional crystalline arrays of the membrane protein bacteriorhodopsin. Two distinct regimes have been found as a function of the intermembrane distance d . In the {open_quotes}coupled{close_quotes} regime for d{lt}250 {Angstrom} the temperature (T{sub m}) of the melting transition decreases with increasing d , demonstrating the effect of the repulsive membrane interactions on the intramembrane protein ordering. For d{gt}250 {Angstrom} a {open_quotes}decoupled{close_quotes} regime is found with higher T{sup *}{sub m} independent of d . Below T{sup *}{sub m} a solid-liquid-solid reentrant behavior is observed as d is increased. {copyright} {ital 1999} {ital The American Physical Society}
Abstract Objectives- Cyclodextrins are useful solubilizing excipients that have gained currency in the formulator's armamentarium based on their ability to temporarily camouflage undesirable physicochemical properties. In this context cyclodextrins can increase oral bioavailability, stabilize compounds to chemical and enzymatic degradation and can affect permeability through biological membranes under certain circumstances. This latter property is examined herein as a function of the published literature as well as work completed in our laboratories. Key findings- Cyclodextrins can increase the uptake of drugs through biological barriers if the limiting barrier component is the unstirred water layer (UWL) that exists between the membrane and bulk water. This means that cyclodextrins are mo...
Nanowires, films, and membranes comprising ordered porous manganese oxide-based octahedral molecular sieves, and methods of making, are disclosed. A single crystal ultra-long nanowire includes an ordered porous manganese oxide-based octahedral molecular sieve, and has an average length greater than about 10 micrometers and an average diameter of about 5 nanometers to about 100 nanometers. A film comprises a microporous network comprising a plurality of single crystal nanowires in the form of a layer, wherein a plurality of layers is stacked on a surface of a substrate, wherein the nanowires of each layer are substantially axially aligned. A free standing membrane comprises a microporous network comprising a plurality of single crystal nanowires in the form of a layer, wherein a plurality of layers is aggregately stacked, and wherein the nanowires of each layer are substantially axially aligned.
The objective of this study was to evaluate the role of collagen membrane and Bio-Oss coverage in healing of an onlay graft to the mandible. Twelve adult sheep each received an onlay bone graft (experiment 1), bone graft+Bio-Gide (experiment 2), and bone graft+Bio-Oss/Bio-Gide (experiment 3) on the lateral surface of the mandible. The animals were euthanized at 4, 8, 12 or 16 weeks after surgery, and findings were analysed by routine microscopy and immunohistochemistry for proliferation (Ki67) and apoptotic (Caspase-3) markers. Grafts were fully incorporated in all specimens. Pronounced resorption was observed in experiment 1. Minimal loss of graft volume was seen in experiment 2 specimens without membrane displacement. A remarkable increase in the augmented region of the mandible was obse...
Abstract A series of studies performed at our center demonstrates that gaseous microemboli (GME) remain a challenge in cardiac surgical procedures. Evaluation of novel oxygenators must address hemodynamic parameters and microemboli capture capability. The objective of this study is to compare two neonatal membrane oxygenators, the Quadrox i (MAQUET Cardiopulmonary AG, Hirrlingen, Germany) and the Capiox RX05 (Terumo Corporation, Tokyo, Japan), with respect to GME capture and hemodynamic energy delivery. The experimental circuit included a Maquet HL 20 heart lung machine, a Heater Cooler Unit HCU 30 (MAQUET Cardiopulmonary AG), a membrane oxygenator (Quadrox i Neonatal or Capiox RX05), and inch tubing from the COBE Heart/Lung Perfusion Pack (COBE Cardiovascular, Inc., Arvada, CO, USA). A Ca...
Tests on a sample of trench water from the Maxey Flats burial ground effectively demonstrated the new Reverse Osmosis Pilot Plant. The effluent from the 50% salt-rejection membrane was decontaminated well enough with the exception of tritium to be discharged to the environment. The performance of the 97% salt-rejection membrane was superior to that of the 50% membrane. A breakthrough and capacity experiment was conducted with Durasil 10 on a simulated Three Mile Island solution. The maximum decontamination factor was extrapolated to be 10/sup 6/, which would reduce the cesium level of TMI water to below the discard limit. Capacity (1/DF = 0.5) was reached at 1260 column volumes. Several adsorbents were tested in the engineering columns for decontamination of cesium-bearing solutions. Under the conditions of the experiment, these adsorbents were ineffective in removing cesium from the solution.
Two perfluorosulfonic acid membranes, Nafion{sup R} 105 and Nafion{sup R} 115 with the same thickness but different equivalent weights (EW = 1000 g/eq. resp. 1100 g/eq.) were characterised by conductivity measurements at different water vapour activities in the temperature range of 25-70{sup o}C. The results demonstrate that a lower membrane equivalent weight opens the possibility to obtain the needed proton conductivity at lower water vapour activity. This is especially important for those fuel cell applications, in which the cell is operated without external humidification of the fuel gases. (author) 5 figs., 5 refs.
The growth of a middle ear cholesteatoma behind a normal tympanic membrane is a rate though possible event. In such cases, CT may provide useful information for diagnosis. The results are presented of a CT study carried out on 14 patients affected with unilateral conductive hearing loss and with normal tympanic membrane. CT allowed the diagnosis of meddle ear cholesteatoma to be made in all cases. All patients were treated with surgery: 8 of them underwent tympanoplasty and 6 explorative tympanotomy. While the diagnosis of cholesteatoma was confirmed in 13 patients, in 1 case tympanosclerosis was diagnosed. CT diagnosis of middle ear cholesteatoma is based on the demonstration of a low-density soft-tissue mass, in association with bone erosion or ossicular dislocation. The author emphasizes the difficulty of a CT diagnosis of cholesteatoma in the patients with middle ear soft-tissue masses in the absence of bone alterations.
Two lines of mouse tumor cells were shown to be capable of aggregating mouse and rabbit platelets in vitro. This process required higher Mg/sup 2 +/ concentrations than were needed by other commonly used platelet-aggregating agents. Platelet-aggregating activity was also found in tumor cell membrane fragments. This membrane-bound platelet-aggregating material contained protein, lipid, and carbohydrate moieties. The presence of all three appeared to be essential for stimulating platelet aggregation. Destruction of any component abolished its activity. Platelet aggregation induced by tumor cell membrane fragments was associated with a secretory release reaction. In this process, growth-promoting activity for tumor cells was also released from platelets. These results underline the importance of platelets in establishing tumor metastases.
Radon proof barriers are used for lowering of radon transport from the soil into the house and the determination of the radon diffusion coefficient is an important parameter to be determined in order to design the minimal thickness of the radon proof insulation. A method has been developed in our laboratory by using modified Lucas cells connected to a radon source and tightly closed onto the top by the tested membranes whose radon diffusion coefficients are being measured. Solving the time-dependent differential equation for radon diffusion in the membrane for well-defined experimental conditions the effective radon diffusion coefficient of the insulating material can be evaluated by comparing the radon concentration decrease in the cell for the first hours with the well-known radioactive decay. First results obtained in several preliminary tests carried out with a parafilm M barrier and two polyethylene membranes are shown ...
The wear behaviour of 722M24 (En40B) steel plasma nitrided at high temperatures for long durations was investigated. Under dry sliding and abrasive-containing lubricated conditions, the wear characteristics of the steel were studied as a function of load, time and white layer thickness. The white layer and the wear debris were characterized by X-ray diffraction. The topography of the wear surface was examined in a scanning electron microscope. The plasma nitriding process was carried out using a 20 kW plasma processing unit in cracked ammonia atmosphere. Treatment times of up to 100 h were employed with temperatures of 550, 570 and 590 C. Wear tests were performed with plasma nitrided AMS 6472 as the counterface material. The tests under abrasive-containing lubricated conditions were carried out with 10% carborundum powder 10 [mu]m in size in SAE-30 machine oil. The wear resistance of the steel was ...
The basic idea is to implement Thomson scattering with free electron laser (FEL) radiation at near-solid density plasmas as a diagnostic method which allows the determination of plasma temperatures and densities in the warm dense matter (WDM) regime (free electron density of n{sub e} = 10{sup 21}-10{sup 26} cm{sup -3} with temperatures of several eV). The WDM regime [1] at near-solid density (n{sub e} = 10{sup 21}-10{sup 22} cm{sup -3}) is of special interest because, it is where the transition from an ideal plasma to a degenerate, strongly coupled plasma occurs. A systematic understanding of this largely unknown WDM domain is crucial for the modeling and understanding of contemporary plasma experiments, like laser shock-wave or Z-pinch experiments as well as for inertial confinement fusion (ICF) experiments as the plasma evolution follows its path through this ...
The present work describes the surface improvement and biocompatibility of TiAl{sub 24}Nb{sub 10} intermetallic alloy using rf plasma nitriding. The nitriding process was carried out at different plasma power from 400 W to 650 W where the other plasma conditions were fixed. Grazing incidence X-ray diffractometry (GIXRD), Auger electron spectroscopy (AES), tribometer and a nanohardness tester were employed to characterize the nitrided layer. Further potentiodynamic polarization method was used to describe the corrosion behavior of the un-nitrided and nitrided alloy. It has been found that the Vickers hardness (HV) and corrosion resistance values of the nitrided layers increase with increasing plasma power while the wear rates of the nitrided layers reduce by two orders of magnitude as compared to those of the un-nitrided layer. This improvement in surface properties of the intermetallic alloy is due to ...
The present work describes the surface improvement and biocompatibility of TiAl_2_4Nb_1_0 intermetallic alloy using rf plasma nitriding. The nitriding process was carried out at different plasma power from 400 W to 650 W where the other plasma conditions were fixed. Grazing incidence X-ray diffractometry (GIXRD), Auger electron spectroscopy (AES), tribometer and a nanohardness tester were employed to characterize the nitrided layer. Further potentiodynamic polarization method was used to describe the corrosion behavior of the un-nitrided and nitrided alloy. It has been found that the Vickers hardness (HV) and corrosion resistance values of the nitrided layers increase with increasing plasma power while the wear rates of the nitrided layers reduce by two orders of magnitude as compared to those of the un-nitrided layer. This improvement in surface properties of the intermetallic alloy is due to formation ...
Using standard brass alloy samples, an approach to reduce the laser-induced breakdown spectroscopy measurement uncertainty was tested and proved. Two important parameters for plasma characterization, the plasma temperature and the electron density, were applied to minimize the signal uncertainties due to uncontrollable experimental parameter variations. Results show that for the pulse-to-pulse analysis, the signal fluctuations can be significantly reduced by utilizing the plasma characteristic information. The major source for the single pulse fluctuations is the redistribution of the characteristic line at different temperatures according to the Boltzmann distribution under LTE. The change of the degree of ionization also contributes to the signal fluctuations. For the multi-pulse analysis, due to the nonlinear relationship between the plasma temperature and the line intensity, it is not applicable to ...
In a prior study, we demonstrated that certain disposable coils are contaminated with zinc and release substantial quantities of Zn during hemodialysis, producing high post-dialysis plasma Zn concentrations. The present investigation was designed to monitor plasma and dialysis fluid Zn and copper throughout dialysis and to estimate patient Zn and Cu uptake. Venous plasma, arterial plasma and coil chamber fluid were sampled periodically throughout dialysis; trace metal concentrations were determined by flame atomic absorption spectrophotometry. Release of considerable quantities of Zn from the coils into the dialysis fluid, with uptake into the patient's plasma, was found. Approximately one-half of the plasma Zn uptake occurred in the first 45 minutes. Coils from different lots released significantly different quantities of Zn. Patient uptake of Zn ...
The Versatile Toroidal Facility (VTF) is a large laboratory plasma machine of 1 meter major radius used to carry out investigations of ionospheric plasma turbulence. Spectral analysis has been performed on plasmas produced by the electron emitters. Interest has focused on the low frequencies below the lower hybrid resonance where ion acoustic and current-convective modes have been observed. Microwaves injected from a 3,000 watt magnetron produce dramatic changes to the low frequency spectrum. First, the parametric decay instability intensifies the ion acoustic modes in the region of plasma heated by the microwaves. Second, the normally dominant current-convective modes are greatly suppressed in the heated region due to the oscillating electric field of the pump wave. When the authors probe beyond the heated region, these two pump wave effects are no longer observed, presumably because the microwaves are ...
An ignition device of the plasma jet type is disclosed. The device has a cylindrical cavity formed in insulating material with an electrode at one end. The other end of the cylindrical cavity is closed by a metal plate with a small orifice in the center which plate serves as a second electrode. An arc jumping between the first electrode and the orifice plate causes the formation of a highly-ionized plasma in the cavity which is ejected through the orifice into the engine cylinder area to ignite the main fuel mixture. Two improvements are disclosed to enhance the operation of the device and the length of the plasma plume. One improvement is a metal hydride ring which is inserted in the cavity next to the first electrode. During operation, the high temperature in the cavity and the highly excited nature of the plasma breaks down the metal hydride, liberating hydrogen which acts as an additional fuel to ...
Electron and ion beam dynamics of the PF-1000 facility were investigated for the first time at its upper energy limit (?1 MJ) in relation to neutron emission, the pinch's plasma ('target') characteristics and some other parameters with the help of a number of diagnostics with ns temporal resolution. Special attention was paid to the temporal and the spatial cross correlations of different phenomena. Results of these experiments are in favour of a neutron emission model based on ion beam-plasma interaction with three important features: (1) the plasma target is hot and confined during a few 'inertial confinement times'; (2) the ions of the main part of the beam are magnetized and entrapped around the pinch plasma target for a period longer than the characteristic time of the plasma inductive storage system and (3) ion-ion collisions (both fusion collisions, due to head-on impacts and ...
Although it has been established that lead is transferred in milk from mother to suckling offspring, the physiological processes and parameters involved are not well understood. Single i.v. doses (0.2 mg/kg) or p.o. doses (2 mg/kg) of radiolabeled lead were administered to lactating and nonlactating female mice, and lead concentrations in blood, plasma, and milk were determined during a 21-day period. Large differences in lead elimination were observed between lactating and nonlactation mice. A significant fraction (25%) of the initial maternal dose (absorbed dose) was transferred to the suckling pups. The ratio of lead concentration in milk to lead concentration in plasma was found to be nearly constant over time. However, the milk-to-blood concentration ratios decreased during the same period. Furthermore, the concentration of lead in milk exceeded the plasma concentration by a factor of approximately 25, indicating that ...
Inductively coupled fluorocarbon (CF4/Ar and C4F8/Ar) plasmas were used to etch HfO2, which is a promising high-dielectric-constant material for the gate of complementary metal-oxide-semiconductor devices. The etch rates of HfO2 in CF4/Ar plasmas exceeded those in C4F8/Ar plasmas. The tendency for etch rates to become higher in fluorine-rich (high F/C ratio) conditions indicates that HfO2 can be chemically etched by fluorine-containing species. In C4F8/Ar plasmas with a high Ar dilution ratio, the etch rate of HfO2 increased with increasing bias power. The etch rate of Si, however, decreasd with bias power, suggesting that the deposition of carbon-containing species increased with increasing the power and inhibited the etching of Si. The HfO2/Si selectivity monotonically increased with increasing power, then became more than 5 at the highest tested bias power. The carbon-containing species to inhibit ...
The sequence of nitride formation during the early stages of plasma nitriding of pure iron was studied by optical microscopy, SEM, TEM and x-ray diffraction. Plasma nitriding at {approximately}490 C in a 25 vol.%H{sub 2} + 75 vol.%N{sub 2} mixture starts with the formation of {gamma}{prime}-Fe{sub 4}N after 40s. Once {gamma}{prime} nucleates, it mainly spreads laterally due to diffusion shortcuts in the discontinuous surface nitride layer. Before {gamma}{prime} is continuous on the surface, {epsilon} nucleates on top of it shortly after 40S. Epsilon is then observed to grow, both inwardly and laterally along with {gamma}{prime}. A compact {gamma}{prime}/{epsilon} bilayer forms on the surface at around 100s. The kinetics of nucleation, growth and compactation of the nitrides observed in the present work was significantly more rapid than in any of the nitriding process reported in the literature, including plasma nitriding. ...
The plasma plume generated by a new type of high energy Janitor known as the railplug, is examined. The railplug is a miniaturized railgun that has the potential for improving ignition characteristics of combustible mixtures in engines. The objective of the study is to gain an uderstanding of the characteristics of the plasma created by a transparent railplug, and to validate a multidimensional computer simulation of the plasma and shock fronts. The nature of the plume emitted by the railplug was examined for three levels of electrical energy while firing into air at a pressure of 1 atm. The computer model is to be used to predict trends in railplug performance for various railplug designs, energies, and ambient conditions. The velocity of the plasma movement inside a transparent railplug was measured, as well as the velocity of the plume ejected from the cavity. A shock is produced at the initiation ...
The effect of the nitrogen uptake in {alpha}-iron upon spark erosion in gaseous and liquid ammonia, plasma nitriding, and plasma immersion ion implantation is studied. The resulting phases and hyperfine parameters, measured by the Moessbauer spectroscopy, are discussed from the point of view of initial conditions of their preparation and subsequent heat and/or mechanical treatment. Spark erosion in the ammonia gas produces fine particles with the dominating ferromagnetic {alpha}-Fe phase (50%). The 20% of specimen volume form {alpha}'-Fe and {alpha}''-Fe{sub 16}N{sub 2} phases. The last 30% occupy the {gamma}'-Fe{sub 4}N, ferro- and paramagnetic {epsilon} phases, and {gamma}-Fe(N). Nitriding in the liquid ammonia allows to incorporate the higher content of nitrogen into {alpha}-iron particles which results in the formation of paramagnetic {epsilon}({zeta})-Fe{sub 2}N phase. This phase also dominates the ...
The effect of the nitrogen uptake in #alpha#-iron upon spark erosion in gaseous and liquid ammonia, plasma nitriding, and plasma immersion ion implantation is studied. The resulting phases and hyperfine parameters, measured by the Moessbauer spectroscopy, are discussed from the point of view of initial conditions of their preparation and subsequent heat and/or mechanical treatment. Spark erosion in the ammonia gas produces fine particles with the dominating ferromagnetic #alpha#-Fe phase (50%). The 20% of specimen volume form #alpha#'-Fe and #alpha#''-Fe_1_6N_2 phases. The last 30% occupy the #gamma#'-Fe_4N, ferro- and paramagnetic #epsilon# phases, and #gamma#-Fe(N). Nitriding in the liquid ammonia allows to incorporate the higher content of nitrogen into #alpha#-iron particles which results in the formation of paramagnetic #epsilon#(#zeta#)-Fe_2N phase. This phase also dominates the surface of #alpha#-iron specimen implanted by nitrogen using ...
The effect of a carbohydrate, a 20% protein, or a carbohydrate +0.3% tryptophan TRP breakfast on plasma large neutral amino acid ratio was studied in 6 healthy men. The carbohydrate-rich meal produced shifts in plasma amino acid concentrations such that plasma TRP/LNAA ratios increased from 0.13 to 0.15 (p<0.04) and the protein meal decreased the ratio from 0.14 to 0.11 (p<0.04) after 1 hour. Addition of 0.3% TRP to the carbohydrate-rich meal increased plasma TRP/LNAA ratios more than 2-fold. The TRP containing meal was thus the only one likely to influence brain 5-HT synthesis, although the difference between the plasma TRP/LNAA ratios after carbohydrate and protein breakfasts suggests that the brain may distinguish, by synthesizing more or less 5-HT, the composition of breakfast meals. (Author).
The heating history of a droplet during its flight can be divided into two phases: (a) the initial phase when evaporation, although it occurs, does not change the heat balance of the droplet much (the case considered in our previous paper and (b) the final phase when the cooling due to evaporation balances the heat flux from the plasma. The later phase is considered in Chen's comment. In our reply, a very straightforward consideration demonstrates that even in the final phase of the droplet flight, the 'rocket' effect can be significant. (reply)
The thermonuclear reactivity of deuterium(D) - tritium(T) fusion plasma with spin-polarized fuel has been studied. Two mechanisms of depolarization, collisions and waves, in the high temperature fusion plasma have been considered. The binary collisions have been found not to change the nuclear spin states. The waves with a frequency of a few GHz, however, changes the spin states appreciably, when {delta}B/B{sub 0} (the ratio of the amplitude of the fluctuating magnetic field to the external field) becomes larger than 10{sup -5}. (author)
This report is devoted to the investigation of the influence of electron collisions and radial non-uniformity of plasma density on phase characteristics, spatial attenuation and wave field structure of slow symmetric electromagnetic waves that propagate along cylindrical waveguide structure. It has been shown that collision rate and radial non-uniformity of plasma density for various parameters of waveguide structure and dielectric affect essentially on the wave characteristics and consequently, on the parameters of gas discharge that is sustained by this wave. The results obtained are of large importance for the construction of the theory of gas discharges that are sustained by the surface electromagnetic waves.
17-4PH stainless steel was modified by direct current (DC) plasma nitriding and titanium nitride film duplex treatment in this study. The microstructure, wear resistance and corrosion resistance were characterized by X-ray diffraction (XRD), pin-on-disk tribological test and polarization experiment. The results revealed that the DC plasma nitriding pretreatment was in favor of improving properties of titanium nitride film. The corrosion resistance and wear resistance of duplex treatment specimen was more superior to that of only coated titanium nitride film.
17-4PH stainless steel was modified by direct current (DC) plasma nitriding and titanium nitride film duplex treatment in this study. The microstructure, wear resistance and corrosion resistance were characterized by X-ray diffraction (XRD), pin-on-disk tribological test and polarization experiment. The results revealed that the DC plasma nitriding pretreatment was in favor of improving properties of titanium nitride film. The corrosion resistance and wear resistance of duplex treatment specimen was more superior to that of only coated titanium nitride film.
Reflection coefficients of electromagnetic waves in a nonuniform plasma layer with electrons, positive ions and negative ions, covering a metal surface are investigated by using the finite-difference-time-domain method. It is shown that the reflection coefficients are influenced greatly by the density gradient on the layer edge, layer thickness and electron proportion, i.e., the effect of the negative ions. It is also found that low reflection or high attenuation can be reached by properly choosing high electron proportion, thick plasma layer, and smooth density gradient in the low frequency regime, but sharp density gradient in the high frequency regime. (authors)
Plasma generated in low-density vapor by a negative ion beam has been studied experimentally and computationally. We show that space charge neutralization of the beam occurs at very low vapor density, and that correspondingly the electron density may be much less than the beam and plasma ion densities. When there is a large local gas density, as in a charge changing cell, the resulting high electron density is also localized to the same region. Therefore, very few electrons will reach a negative ion accelerator even if it is placed one or two beam diameters from such a cell.
With the aim of optimizing the nitriding process parameters (temperature and gas mixture ) experimental studies of the plasma nitriding of Ck 15 steel were carried out, using a D. C. glow discharge. Nitriding treatments were performed at 450, 500 and 550 and N_2/H_2 volume ratio of 3/1, 1/1 and 1/3 for 5 hours. Nitriding treatment produces modified surface layer consisting of an outer compound layer and an inner diffusion layer.The plasma nitriding of Ck 15 produce single white layer consisting of #gamma#-(Fe_4N).
This paper provides a concise summary of the current status of the research and future perspectives discussed in the Mini-Conference on Angular Momentum Transport in Laboratory and Nature. This Mini-conference, sponsored by the Topical Group on Plasma Astrophysics, was held as part of the American Physical Society's Division of Plasma Physics 2007 Annual Meeting (November 12{16, 2007). This Mini-conference covers a wide range of phenomena happening in fluids and plasmas, either in laboratory or in nature. The purpose of this paper is not to comprehensively review these phenomena, but to provide a starting point for interested readers to refer to related research in areas other than their own.
We show that the eigenvalue equations describing a cylindrical ideal magnetophydrodynamicsw (MHD) plasma interacting with a thin resistive wall can be put into the standard mathematical form: ??? = ??? ?. This is accomplished by using a finite element basis for the plasma, and by adding an extra degree of freedom corresponding to the electrical current in the thin wall. The standard form allows the use of linear eigenvalue solvers, without additional interations, to compute the complete spectrum of plasma modes in the presence of a surrounding restrictive wall at arbitrary separation. We show that our method recovers standard results in the limits of (1) an infinitely resistive wall (no wall), and (2) a zero resistance wall (ideal wall).
Experiments are described on a plasma cathode with biased grids to prevent entry of ions into the electron extraction gap. The cathode has potential applications to the generation of high-current pulsed electron beams. Operation at 20 A/cm"2 is theoretically possible. The source combines the low average power consumption of a plasma cathode with many of the attractive features of thermionic cathodes, such as space-charge-limited extractor gap electron flow, fast turn-on, and no diode closure. Initial experiments are reported at the 2 A/cm"2 level for pulse lengths to 160 #mu#s.
With the help of heat balance equation and high temperature thermodynamic function, the calibration relation of jet temperature with discharge power, gas flow rate was obtained for nitrogen thermal plasma. It was shown that the results were agreed with the principle of similarity. The jet temperature was a function of Peff/f, instead of a general two variables function of Peff and f, which were effective discharge power and working gas flow rate, respectively. A related discussion has been given; it will be referable to thermal plasma applications. (authors)
Dimethyl methylphosphonate (DMMP), a chemical simulant of the nerve gas GB, was decontaminated with a nonthermal atmospheric pressure plasma. The decontamination efficiency was measured qualitatively by means of Fourier transform spectroscopy and quantitatively by means of gas chromatography. With helium gas only, 10g/m2 of DMMP on an aluminum surface was 99.9% decontaminated in 2min, furthermore, with the addition of 5% of oxygen gas, it was 99.99% decontaminated in 10min. Given the low input power (<100W) and temperature (<75degreeC), this plasma is eligible for nondestructive decontamination of almost all material surfaces.
The validity is given to the newly proposed two {delta}f method for neoclassical transport calculation, which can be solve the drift kinetic equation considering effects of steep plasma gradients, large radial electric field, finite banana width, and an orbit topology near the axis. The new method is applied to the study of ion transport with steep plasma gradients. It is found that the ion thermal diffusivity decreases as the scale length of density gradient decreases, while the ion particle flux due to ion-ion self collisions increases with increasing gradient. (author)
A brief review is presented of transport in the boundary region of magnetized plasmas by blob-like filaments. Such structures have enhanced levels of particles and heat, are elongated along the magnetic field lines and are localized in the drift plane across the field. The motion of an isolated blob structure is described in some detail and the contribution of such filaments to turbulence-driven transport are discussed. Results are presented from numerical simulations and probe measurements in tokamak plasmas. An interpretation is given of the measured dependence of particle density and transport on experimental control parameters in the scrape-off layer. (author)
A computer model of an electrothermal accelerator has been developed which applies to the plasma generator as well as the gun barrel, and it for the first time allows study of the interdependent physical processes in both components simultaneously. The code comprises a 2D transient description of the plasma arc, a 2D, two-phase interior ballistics module, and a preprocessor delivering the required plasma physical data. Some results on the flow field, pressure and temperature in a typical accelerator are presented, and probable limitations on the performance of such a system are discussed. The code is to be applied to different concepts of electrothermal chemical guns.
Autophagy is a ubiquitous catabolic process that ensures organism’s well-being by sequestering a wide array of undesired intracellular constituents into double-membrane vesicles termed...Full Text Available
Small angle neutron scattering (SANS) on the unilamellar vesicle populations (diameter 500 and 1000 angstrom) was used to characterize lipid vesicles from dimyristoylphosphatidylcholine (DMPC) at three phases (gel, ripple, and liquid). Parameters of vesicle populations and internal structure of the DMPC bilayer were characterized on the basis of the Separated Form Factor (SFF) model. Parameters of the internal bilayer structure (thickness of the membrane and the hydrophobic core, hydration, and surface area of lipid molecule) were determined on the basis of the Hydrophobic-Hydrophilic (HH) approximation of neutron scattering length density across the bilayer r(x) and of the Step Function (SF) approximation of r(x). It was demonstrated in frame of HH approximation that DMPC membrane thickness in liquid phase (T=30 degrees) depends on the membrane curvature. The dependence of the DMPC membrane thickness ...
The LW blood group antigens reside on a 42-kDa erythrocyte membrane glycoprotein that was purified by immunoaffinity and partially sequenced. From this information, a specific PCR-amplified DNA fragment...Full Text Available
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In Chlamydomonas reinhardtii y-1, newly synthesized chlorophyll a/b-binding apoproteins are degraded when chlorophylls are not present for assembly of stable light-harvesting...Full Text Available
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Auxin-induced pea (Pisum sativum) stem section elongation is enhanced at levels of 3 to 40 micromolar by six new classes of alkane derivatives additional to those described earlier,...Full Text Available
BACKGROUND: Epidermolysis bullosa (EB) is a group of heritable diseases that manifest as blistering and erosions of the skin and mucous membranes. In the dystrophic forms of EB (DEB), the diagnostic...Full Text Available
Cleavage of membrane-associated proteins with the release of biologically active macromolecules is an emerging theme in biology. However, little is known about the nature and regulation of the involved...Full Text Available
Antibodies against feline leukemia virus (FeLV) and the feline oncornavirus-associated cell membrane antigen (FOCMA) were transferred from pregnant cats to their suckling kittens. All of these kittens...Full Text Available
Some laboratory experiments have suggested that power-frequency electric and magnetic fields (EMF) may be capable of influencing calcium efflux from cell membranes, pineal function, and circadian rhythms....Full Text Available
The 37/67-kd laminin receptor, LAMR, is a multifunctional protein that associates with the 40S ribosomal subunit and also localizes to the cell membrane to interact with the extracellular matrix. LAMR...Full Text Available
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The responses of the vacuolar membrane (tonoplast) proton-pumping inorganic pyrophosphatase (H+-PPase) from oat (Avena sativa L.) roots to changes in Mg2+ and...Full Text Available
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Effects of MgCl2 and free fatty acids (FFA) on galactolipid:galactolipid galactosyltransferase (GGGT) and UDP-galactose: 1,2-diacylglycerol galactosyltransferase (UDGT) in chloroplast envelope...Full Text Available
The delivery of proteins and organelles to the vacuole by autophagy involves membrane rearrangements that result in the formation of large vesicles called autophagosomes. The mechanism underlying autophagosome...Full Text Available
The cell is modeled as an ellipsoid with shell and the surface stress distribution calculated by means of the Maxwell Stress Tensor. The cell membrane is treated as incompressible material having both bending and shear energies of deformation. Employing the principle of virtual work, cell volume (and hence shape) is computed as a function of the external field strength and orientation with respect to the field. The following results were obtained: (1) The surface stresses that develop or the cell membrane are distributed having both normal and tangential components that act together to produce a rounding of the cell. (2) If the tangential component of the stress is ignored, then higher field strengths are needed to produce similar deformation (shape change) of cells. (3) The threshold value of the applied field, i.e, the field strength at which the volume (shape) of the cell changes abruptly, occurs at approximately 55V/cm. Above the threshold ...
Background:Continuous renal replacement therapy is used to manage fluid and solute imbalances in critically ill patients but may affect the clearance of concurrently administered...Full Text Available
Oxygenated sterol compounds (OSC), when incubated for 1 hr with human erythrocytes in lipoprotein-depleted medium at concentrations of 0.625-5 x 10/sup -5/M, are inserted into the cell membrane and remain there despite subsequent washing of the cells. The insertion results in expansion of the surface area of the red cell ghost membrane, an increase in critical hemolytic volume, and as a consequence, in dimished osmotic fragility of the erythrocytes. This effect is seen with echinocyte-forming as well as with non-echinocyte-forming OSC. Erythrocytes treated with OSC do not differ from control cells with respect to their mean cell volume (MCV) in isotonic solution, water content, ion fluxes, and filterability through polycarbonate filters. The shift of the osmotic fragility curve toward lower NaCl concentrations is proportional to the amount of OSC inserted into the red cell membrane. 7BETA-Hydroxycholesterol, ...
Experiments were performed to investigate the involvement of the cell membrane in the excision DNA repair process in Escherichia coli. Two membrane-binding drugs, procaine and phenethyl alcohol (PEA), inhibited liquid-holding recovery (LBR) in u.v.-irradiated E. coli wild-type and recA strains. In uvrB and polA strains where, after u.v.-irradiation, LHR was absent the two drugs had no effect. Both drugs markedly reduced the removal of u.v.-induced thymine dimers in the DNA of wild-type cells (H/r30). Analysis by alkaline sucrose gradients revealed that PEA inhibited the incision step in excision repair. In contrast, procaine had no effect on incision but apparently inhibited the late steps in excision repair. PEA dissociated DNA from the cell membrane, whereas procaine did not. The results suggest that the two drugs PEA and procaine inhibit LHR and the excision repair process operating on u.v.-induced damage in E. coli by ...
Cyclophilins (Cyps), the intracellular receptors for Cyclosporine A (CsA), are responsible for peptidyl-prolyl cis-trans isomerisation and for chaperoning several membrane proteins. Those functions...Full Text Available
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A balanced application of chemiosmosis to plant mitochondria is presented. Electron transport carriers are sequenced to achieve proton translocation across the inner membrane. The processes of proton translocation, use, and release are integrated to yield a description of the effective proton gradient available for metabolite transport and ATP synthesis. 27 references, 6 figures.
The membrane properties of isolated cultured microglia have been extensively studied but it is important to understand their properties in situ, where they protect the brain against...Full Text Available
E-cadherins belong to a family of membrane-bound, cellular adhesion proteins. Their adhesive properties mainly involve the two N-terminal extracellular domains (EC1 and EC2). The junctions between these...Full Text Available
Atg9 is a transmembrane protein essential for autophagy which cycles between the Golgi network, late endosomes and LC3-positive autophagosomes in mammalian cells during starvation through a mechanism...Full Text Available
Amino acid transport was studied in membranes of the peptidolytic, thermophilic, anaerobic bacterium Clostridium fervidus. Uptake of the negatively charged amino acid L-glutamate, the neutral amino...Full Text Available
The adhesive proteins secreted by marine mussels form a natural glue that cures rapidly to form strong and durable bonds in aqueous environments. These mussel adhesive proteins contain an unusual...Full Text Available
The ventromedial hypothalamus (VMH) plays a central role in the regulation of the female reproductive behavior lordosis, a behavior dependent upon the sequential activation of receptors for the ovarian...Full Text Available