Fluid and Plasma

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Multi-fluid Plasma Modelling

Multi-fluid Plasma Modelling

In experimental fusion plasmas, it is often the case that the velocity distribution of the particles does not conform to the Maxwell-Boltzmann distribution; this is due to external heating, used both to compensate for energy losses, and to increase the plasma tempera- ture. Often, the heating mechanisms heat only particles within a certain velocity range. Energy is then transferred from the component of the plasma resonant with the heating mechanism to the rest of the plasma through collisions. If the heating process were ceased, the plasma would eventually return to a Maxwellian distribution function. However, if the heating process is continuous, as is the case in modern tokamak experiments, then a dynamic equilibrium arises in which energy is transferred into the resonant component of the distribution function at the same rate as it looses energy to the bulk of the plasma. In this dynamic equilibrium, the high-energy component of the plasma can be seen as a stationary ‘bump’ in the tail of the velocity distribution function of the whole plasma, as shown in Figure 1.2. For plasmas with a significant amount of heating, this ‘bump’ can cause the distribution function to be highly non-Maxwellian, and so a temperature cannot be defined. It is not currently known how much of an effect neglecting the contribution of a high-energy component of the distribution function has upon the fluid models previously discussed; this thesis aims to make some progress towards answering this question.

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Hermes : Global plasma edge fluid turbulence simulations

Hermes : Global plasma edge fluid turbulence simulations

The edge of magnetically confined plasmas, such as tokamaks, is where hot confined plasma encounters neutral gas, material surfaces, and the associated impurities. The transport of heat and particles in this region determines the heat loads and erosion rates of plasma facing components (PFCs). Predicting this transport, and exploring means of reducing heat fluxes to PFCs, has played an important role in designing the ITER divertor [1], and will be critical to the design of a future DEMO device [2, 3]. One of the uncertainties in making these predictions is the transport across the magnetic field, which is not well described by diffusion [4, 5], and is thought to be turbulent [6]. Since the fluctuations can be of similar spatial scales and magnitude to average profiles, significant effort has been devoted to developing and testing 3D flux-driven fluid turbulence simulation codes, including GBS [7, 8], TOKAM-3D [9] and TOKAM3X [10].

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Plasma and synovial fluid microRNAs as potential biomarkers of rheumatoid arthritis and osteoarthritis

Plasma and synovial fluid microRNAs as potential biomarkers of rheumatoid arthritis and osteoarthritis

Ethical approval for this study was granted by the ethics committee of Kyoto University Graduate School and Fac- ulty of Medicine. Informed consent was obtained from 108 participants (40 with RA, 38 with knee OA, and 30 as HC, Tables 1 and 2). According to the request of the eth- ics committee, HCs were limited between 20 and 65 years old. RA and OA were diagnosed according to the criteria of the American College of Rheumatology [22,23]. Both peripheral blood and synovial fluid were obtained from 20 patients with RA and 22 patients with OA. Blood sam- ples were collected with ethylenediaminetetraacetic acid dipotassium salt (EDTA-2K) containing tube to separate plasma. Both of samples were centrifuged 400 g for seven minutes and stored at -20°C until analyses.

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Pharmacokinetics and pharmacodynamics of linezolid in plasma/cerebrospinal fluid in patients with cerebral hemorrhage after lateral ventricular drainage by Monte Carlo simulation

Pharmacokinetics and pharmacodynamics of linezolid in plasma/cerebrospinal fluid in patients with cerebral hemorrhage after lateral ventricular drainage by Monte Carlo simulation

Objective: We investigated the pharmacokinetic (PK) and pharmacodynamic (PD) parameters of linezolid in patients who had suffered cerebral hemorrhage after lateral ventricular drainage. Materials and methods: Ten patients with cerebral hemorrhage after lateral ventricular drainage with stroke-associated pneumonia who were given linezolid were enrolled. Plasma and cerebrospinal fluid (CSF) samples were taken at appropriate intervals after the first administration of linezolid and assayed by high-performance liquid chromatography (HPLC). Then, PK parameters were estimated, and a Monte Carlo simulation was used to calculate the probability of target attainments (PTAs) for linezolid achieving the PK/PD index at different minimal inhibitory concentrations (MICs).

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Spectrally Condensed Fluid Turbulence and L-H Transitions in Plasma

Spectrally Condensed Fluid Turbulence and L-H Transitions in Plasma

Recent experimental and theoretical studies of two-dimensional (2D) turbulence reveal that spectrally con- densed turbulence which is a system of coupled large-scale coherent flow and broadband turbulence, is similar to plasma turbulence near the L-H transition threshold. Large condensate vortices fed via the turbulent inverse energy cascade, can control both the level of the broadband turbulence by shear decorrelation, and the energy injected into turbulence at the forcing scale via sweeping of the forcing-scale vortices. The interaction between these ingredients of spectrally condensed fluid turbulence is in many aspects similar to the interactions in the zonal flow-GAMs-turbulence system in plasma. In this paper we overview recent results on condensed 2D turbulence and present evidence of interaction between its three components: condensate structures, turbulence and forcing- scale vortices. This is compared with the modifications in the spectra of plasma electrostatic potential during L-H transitions. It is shown that mean zonal flows are spatially and temporally correlated with both the broadband turbulence and with the narrow spectral range identified as the spectral range of the underlying instability.

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Relativistic fluid simulation of plasma vacuum expansion with LTE closure

Relativistic fluid simulation of plasma vacuum expansion with LTE closure

presence of a plasma, the limited time step size of a simulation may cause the plasma frequency to be impossible to resolve. Finally, in fluid simulations, mix- ing of electrons both as a result of the ensemble quantities being single-valued (opposing streams cancel out their momentum leaving just a high energy den- sity, effectively thermalizing instantly) and as a result of numerical diffusion, can cause unphysical thermalization of the electrons. This results in the waves being damped more than they would be in a real plasma. An easy way to check for these effects is using Fourier analysis. First, the fields in the simulation area are initialized with white noise. This way, waves with all wave-vectors permitted by the simulation grid are present. A spatial Fourier transform (two or three-dimensional depending on the dimensionality of the simulation) of the transverse component of the electric field at each time step now gives the phase and amplitude of the waves for different wave vectors per time step. To find the frequency at which each wave oscillates, a second Fourier transform over time is performed on the spatial Fourier transforms, which shows an amplitude peak at this frequency, with a breadth depending on the duration of the oscillation. The location of these peaks can be directly compared to the analytical value.

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Lipid profiling of suction blister fluid: comparison of lipids in interstitial fluid and plasma

Lipid profiling of suction blister fluid: comparison of lipids in interstitial fluid and plasma

The total concentration of quantified lipids was ap- proximately five-fold higher in plasma compared to SBF. This is in agreement with previous data on lipid frac- tions in human blister fluid [17, 19]. While the overall lipid profiles of plasma and SBF were similar, there were small yet significant differences in both lipid class and species composition. On a lipid class level, SBF had a larger fraction of lysophospholipids (LPC and LPE) and DG than plasma. These point to a higher release of fatty acid esters from PC/PE and TG in SBF compared to plasma. Indeed, fractions of PC, PE, and TG were signifi- cantly lower in SBF. Although levels of NEFAs were not determined in this study, LC-MS scan data from pooled SBF versus plasma samples lend support to the notion that NEFAs are more abundant in SBF. Furthermore, plasma and SBF samples could successfully be discrimi- nated with an OPLS-DA model, and a subsequent VIP analysis identified several DG and LPC species that were significantly under- or overrepresented in SBF. Our analyses cannot exclude that the differences in lipid pro- files between plasma and SBF are artefacts of the fluid collection or lipid extraction (i.e., that lipolysis is stimu- lated by the blister formation per se), or that lipids are metabolized to a greater extent during extraction from SBF compared to plasma. Future studies should aim to resolve these questions using microneedle systems to extract pure dermal interstitial fluid.

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Disposition and effect of intra-articularly administered dexamethasone on lipopolysaccharide induced equine synovitis

Disposition and effect of intra-articularly administered dexamethasone on lipopolysaccharide induced equine synovitis

The pharmacokinetic model fitted to experimental syn- ovial fluid dexamethasone data satisfactory mimicked the data and no major bias or model misspecifications were suspected (Figs. 3 and 4). Quantitative information about synovial fluid and plasma disposition of dexamethasone was provided (Table  2). To our knowledge, the dexa- methasone concentration–time course in synovial fluid has not previously been reported. In plasma, the total clearance, the central and peripheral volume of distribu- tion and the initial and terminal half-lives were consist- ent with the literature [8, 21, 29, 30]. Dexamethasone was removed from the joint when synovial fluid was col- lected and possibly by enzymatic breakdown in the joint. The cumulative amount directly removed from the joint was 0.5–2.1% of the administered dose. This a suggest a systemic bioavailability around 98–99.5% for dexameth- asone after IA injection in the inflamed joint, which is consistent with the bioavailability of dexamethasone after IA-administration in the healthy carpal joint [8]. The very low value for k el indicate that the half-life of dexametha-

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Fluid volume control during short term space flight and implications for human performance

Fluid volume control during short term space flight and implications for human performance

They found a 9 % increase in plasma protein concentration on flight day 1, and a 17 % reduction in plasma volume by 22 h of flight. This agrees with the early in-flight hemoconcentration seen by others (Kirsch et al., 1984) and establishes that plasma volume contraction occurs quickly in microgravity. This hemoconcentration probably results from increased upper- body vascular pressures in microgravity (Parazynski et al., 1991) and perhaps reduced interstitial pressures (Estenne et al., 1992); both factors would encourage transcapillary fluid filtration into upper-body interstitial spaces, and substantial filtration can occur in minutes (Watenpaugh et al., 1992). The early hemoconcentration is all the more notable given the probable concomitant tissue fluid reabsorption from the legs into the circulation (Thornton et al., 1992). Although some protein may leave the circulation early in flight, the increased plasma protein concentration on flight day 1 does not support extravasation of protein as a primary mechanism for early in- flight net capillary filtration and plasma volume contraction. Increased plasma protein concentration increases plasma colloid osmotic pressure and, therefore, opposes capillary filtration.

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Failure to detect an effect of prolactin on pulmonary surfactant and adrenal steroids in fetal sheep and rabbits

Failure to detect an effect of prolactin on pulmonary surfactant and adrenal steroids in fetal sheep and rabbits

Recent reports have indicated an association between low cord prolactin (PRL) and the occurrence of respiratory distress syndrome in premature infants, and it is reported that PRL administration increases the lecithin content of fetal rabbit lung. We administered 1 mg ovine PRL to 32 rabbit fetuses on day 24 of gestation and evaluated lung phospholipid synthesis and content on day 26. Compared with diluent-injected littermates, PRL had no effect on the rate of choline incorporation into lecithin, tissue content of phospholipid and disaturated lecithin, or plasma corticoids. However, both choline incorporation and corticoids were increased in all animals undergoing surgery compared with unoperated controls. We also infused PRL (1 mg/day, i.v.) into three fetal sheep continuously over five periods of 5-8 days. Although supraphysiologic concentrations of PRL were achieved in plasma and amniotic fluid, there was no effect of this treatment on the flux of tracheal fluid surfactant or on plasma concentrations of corticoids of dehydroepiandrosterone sulfate. Thus, in this study, we failed to detect either a stimulation of the surfactant system or an adreno-corticotropic effect by PRL as previously postulated. This suggests that the relationship between PRL and respiratory distress sundrome is an indirect association.

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Sample Preparation In Bioanalysis: A Review

Sample Preparation In Bioanalysis: A Review

Able to remove the unwanted plasma proteins from plasma fluid samples prior to analysis Protein precipitation plates can be used in a wide range of aqueous and organic sample preparation including total drug analysis and sample preparation prior to HPLC or LCMS/MS Protein precipitation plates are compatible with small volume of solvent Protein precipitation plate contains hydrophobic PTFE membrane as a prefilter removes the unwanted precipitated proteins prior to analysis By using the new protein precipitate filter plate, precipitating solvent is added first followed by the plasma sample. This method does not require any mixing. Generally these plates are fitted to 96 well extraction plates. This new process showed 90% removal of plasma proteins when compare to the old method 60-65%

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The elimination half-life of crystalloid fluid is shorter in female than in male volunteers: a retrospective population kinetic analysis

The elimination half-life of crystalloid fluid is shorter in female than in male volunteers: a retrospective population kinetic analysis

The present evaluation shows that the plasma volume expansion and the rate of elimination after infusion of a standardized volume of crystalloid fluid cannot be as- sumed to be equal in males and females. Gender appar- ently constitutes a bias in mixed cohorts of volunteers where the kinetics of crystalloid fluid is studied. For good, most of the previously performed studies have in- cluded one gender only. Although less desired in the present report, only one gender was included in each of the seven studies included here. However, all experi- ments were planned and supervised by the author, and during the past 20 years, great care has been taken to perform them in the same highly standardized fashion. The results can therefore be taken to design and power a prospective trial to confirm the observations. The physiological responses to fluid, both with regard to cen- tral hemodynamics and water-retaining hormones, should then be patterned and used as time-varying co- variates in a fluid volume kinetic analysis of the same type as the present one.

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Continuous glucose control in the ICU: report of a 2013 round table meeting

Continuous glucose control in the ICU: report of a 2013 round table meeting

Interstitial fluid glucose is generally measured with subcutaneous probes, often inserted on the abdominal wall or upper arm. Interstitial fluid glucose levels depend on the rate of glucose diffusion from plasma to the inter- stitial fluid and the rate of uptake by subcutaneous tissue cells; hence, they are influenced by blood flow, the meta- bolic rate of adjacent cells, capillary permeability, degree of hydration or edema, and so on, all of which may be altered in critically ill patients [18]. Several subcutaneous devices have been tested in critically ill patients and have been shown to have good agreement with reference arter- ial and venous samples [12,22-24]. Moreover, similar ac- curacy has been reported in critically ill patients with and without shock requiring norepinephrine therapy [22], and in cardiac surgery versus non-critically ill patients [25,26]. Nevertheless, the accuracy of interstitial fluid monitoring needs to be further investigated, in particular in unstable patients. One concern with subcutaneous interstitial fluid probes is the tissue trauma created during insertion, such that measurements may be less accurate for several hours after insertion. There is a time lag between change in blood glucose and that measured in the interstitial fluid, which is, however, unlikely to result in ineffective treat- ment in case of an emerging hypo- or hyperglycemic event [27-30]. The clinical relevance of this time-lag needs to be contrasted against current practice with a typical delay of 5 to 10 minutes to take the sample and to measure glu- cose on an analyzer.

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Simulation of Radial Variation of Neutral Atoms on Edge Plasma of Small Size Divertor Tokamak

Simulation of Radial Variation of Neutral Atoms on Edge Plasma of Small Size Divertor Tokamak

directed towards the X-point has been observed in the scrape off layer (SOL) on several tokomaks [3,4]. The simulation with B2SOLPS [5-7], UEDGE [6] and EDGE2D [8] reproduced rotation in the same direction. However, recent work on small size divertor tokamak indicates that the poloidal distribution of neutral has essential influence on L-H transition threshold power. Moreover, gas puff increased the plasma temperature, plasma density and radial electric field in the edge plasma of this tokamak. Therefore, in the present paper modeling of the impact of gas (neutral) puff on tokamak edge plasma is performed by means of the B2SOLPS0.5.2D fluid transport code for NBI shots for small size divertor tokamak. The impact of gas (neutral) puff on plasma parameters, plasma heat fluxes and radial electric field are investigated.

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HISTOLOGICAL AND IMMUNOHISTOCHEMICAL STUDY OF PANCREATIC ISLET BETA CELLS OF DIABETIC RATS TREATED WITH ORAL VANADYL SULPHATE

HISTOLOGICAL AND IMMUNOHISTOCHEMICAL STUDY OF PANCREATIC ISLET BETA CELLS OF DIABETIC RATS TREATED WITH ORAL VANADYL SULPHATE

day) after three months VS treatment. Thus STZ injec­ tion largely increased plasma glucose and fluid intake levels and VS treatment returned both of these diabetic signs (hyperglycemia and polydipsia) to normal levels. Diabetic animals responded to the VS treatment with two sensitivities; while the large majority of the diabetic ani­ mals displayed stable normoglycemic values, others showed fluctuatin g values and then found stable normoglycemia. One animal remained hyperglycemic even after long-term treatment.

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“Essential” hypernatremia due to ineffective osmotic and intact volume regulation of vasopressin secretion

“Essential” hypernatremia due to ineffective osmotic and intact volume regulation of vasopressin secretion

A physiological explanation for sustained hyperosmolality was sought in a patient with histiocytosis. During 23 days of observation with only sodium intake regulated at 100 mEq daily, elevation (mean 310 mOsm/kg of water) and fluctuation (range 298-323) of the fasting plasma osmolality were recorded. The presence of endogenous vasopressin was indicated by the patient's ability to concentrate the urine to as high as 710 mOsm/kg of water with a creatinine clearance of 84 cc/min, and by dilution of the urine in response to alcohol. The failure of increasing fluid intake to as high as 6.2 liters daily to lower the plasma osmolality indicated that deficient fluid intake was not solely responsible for the elevated plasma osmolality. Hypertonic saline infusion during water diuresis resulted in the excretion of an increased volume of dilute urine. The water diuresis continued despite a rise in plasma osmolality from 287 to 339. An isotonic saline infusion initiated during hydropenia resulted in a water diuresis which continued despite a rise in the plasma osmolality from 303 to 320. Stable water diuresis induced during recumbency by either oral ingestion of water or

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Parotid fluid cortisol and cortisone

Parotid fluid cortisol and cortisone

However parotid fluid cortisol plus cortisone rose from 0.8 to 2.6 µg/100 ml after ACTH and to only 2.2 after estrogen. This rise resembled that of the plasma dialyzable cortisol (control 0.4, ACTH 1.8, estrogen 1.2 µg/100 ml) rather than the increase in total plasma cortisol which was over twice as high after estrogen as after ACTH. Thus parotid fluid

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JC Virus Quasispecies Analysis Reveals a Complex Viral Population Underlying Progressive Multifocal Leukoencephalopathy and Supports Viral Dissemination via the Hematogenous Route

JC Virus Quasispecies Analysis Reveals a Complex Viral Population Underlying Progressive Multifocal Leukoencephalopathy and Supports Viral Dissemination via the Hematogenous Route

Opportunistic infection of oligodendrocytes by human JC polyomavirus may result in the development of progressive multifocal encephalopathy in immunocompromised individuals. Neurotropic JC virus generally harbors reorganized noncoding control region (NCCR) DNA interspersed on the viral genome between early and late coding genes. By applying 454 sequencing on NCCR DNA amplified from body fluid samples (urine, plasma, and cerebrospinal fluid [CSF]) from 19 progressive multifocal leukoencephalopathy (PML) patients, we attempted to reveal the composition of the JC polyomavirus population (the quasispe- cies, i.e., the whole of the consensus population and minor viral variants) contained in different body compartments and to bet- ter understand intrapatient viral dissemination. Our data demonstrate that in the CSF of PML patients, the JC viral population is often a complex mixture composed of multiple viral variants that contribute to the quasispecies. In contrast, urinary JC virus highly resembled the archetype virus, and urine most often did not contain minor viral variants. It also appeared that archetype JC virus could sporadically be identified in PML patient brain, although selection of rearranged JC virus DNA was favored. Com- parison of the quasispecies from different body compartments within a given patient suggested a strong correlation between the viral population in plasma and CSF, whereas the viral population shed in urine appeared to be unrelated. In conclusion, it is shown that the representation of viral DNA in the CSF following the high-level DNA replication in the brain underlying PML has hitherto been much underestimated. Our data also underscore that the hematogenous route might play a pivotal role in viral dissemination from or toward the brain.

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Urea based osmoregulation in the developing embryo of oviparous cartilaginous fish (Callorhinchus milii): contribution of the extraembryonic yolk sac during the early developmental period

Urea based osmoregulation in the developing embryo of oviparous cartilaginous fish (Callorhinchus milii): contribution of the extraembryonic yolk sac during the early developmental period

Earlier studies demonstrated considerable amounts of urea in the early-stage embryonic body of several cartilaginous fishes (Needham and Needham, 1930). Read (Read, 1968b) further elucidated that the urea concentrations in embryos and yolks are nearly equal in oviparous skate R. binoculata, and that the urea concentration in the embryos is within the range of urea levels in body fluid of adult elasmobranchs throughout development. In the present study, we directly measured the urea concentration in the embryonic body fluid (blood plasma); the composition of embryonic body fluid was similar to that in adult fish, suggesting that the elephant fish embryo has an ability to retain urea in its body from the early developmental period. To our knowledge, only a few earlier studies have provided evidence that the developing embryo of oviparous cartilaginous fish produces urea. Read (Read, 1968a) demonstrated that embryos of R. binoculata have OTC and ARG activities, and that those enzyme activities were increased as development proceeded. More recently, research using R. erinacea showed the presence of CPSIII, OTC, ARG and GS activities in 4 and 8 month old embryos (Steele et al., 2004). In elephant fish, we detected the embryonic expression of mRNAs encoding a series of OUC enzymes (GS1, GS2, CPSIII, OTC and ARG2) from stage 28, in which the external gill starts to extend from the gill slits, and found that the abundance of those transcripts was markedly increased as the hatching stage approached. The change in

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Rheological behavior of human blood in uniaxial extensional flow

Rheological behavior of human blood in uniaxial extensional flow

sample, the temporal evolution of the filament diameter shows a small elasto-capillary region (0.18 < t /ms ≤ 0.24 in air and 0.67 < t /ms ≤ 0.76 in oil), in which the filament presents a quasi-cylindrical shape (cf. Fig. 4b1 and 4b2) and the extensional relaxation time can be estimated. Near breakup (t ≥ 0.28 ms in air and t ≥ 0.95 ms in silicone oil), the filament at the top and bottom ends thins faster than at the central region, which eventually leads to the formation of a single central droplet. Although the breakup of the plasma filament looks similar to that of a Newtonian fluid, the thin tails close to the top and bottom plates, indicated by the arrow in Figure 4b1 and 4b2, suggest a slight viscoelastic behavior of human plasma. A similar filament shape was observed in the filament thinning and breakup of weakly elastic fluids, in which the formation of a tail indicates that viscoelasticity acts against the breakup by increasing the breakup time [36,37]. Nevertheless, the very weak viscoelastic character of human plasma seen here contrasts with previous observations of Brust et al. [19]. The differences in the human plasma behavior in extensional flow between these two works may perhaps be attributed to the different experimental conditions used in both investigations, such as the concentration of anticoagulant used in blood collection.

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