932 resultados para Eklund, Hjalmar Magnus
Resumo:
A new method for determining the temporal evolution of plasma rotation is reported in this work. The method is based upon the detection of two different portions of the spectral profile of a plasma impurity line, using a monochromator with two photomultipliers installed at the exit slits. The plasma rotation velocity is determined by the ratio of the two detected signals. The measured toroidal rotation velocities of C III (4647.4 angstrom) and C VI (5290.6 angstrom), at different radial positions in TCABR discharges, show good agreement, within experimental uncertainty, with previous results (Severo et al 2003 Nucl. Fusion 43 1047). In particular, they confirm that the plasma core rotates in the direction opposite to the plasma current, while near the plasma edge (r/a > 0.9) the rotation is in the same direction. This technique was also used to investigate the dependence of toroidal rotation on the poloidal position of gas puffing. The results show that there is no dependence for the plasma core, while for plasma edge (r/a > 0.9) some dependence is observed.
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High-frequency extensions of magnetorotational instability driven by the Velikhov effect beyond the standard magnetohydrodynamic (MHD) regime are studied. The existence of the well-known Hall regime and a new electron inertia regime is demonstrated. The electron inertia regime is realized for a lesser plasma magnetization of rotating plasma than that in the Hall regime. It includes the subregime of nonmagnetized electrons. It is shown that, in contrast to the standard MHD regime and the Hall regime, magnetorotational instability in this subregime can be driven only at positive values of dln Omega/dlnr, where Omega is the plasma rotation frequency and r is the radial coordinate. The permittivity of rotating plasma beyond the standard MHD regime, including both the Hall regime and the electron inertia regime, is calculated.
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The Velikhov effect leading to magnetorotational instability (MRI) is incorporated into the theory of ideal internal kink modes in a differentially rotating cylindrical plasma column. It is shown that this effect can play a stabilizing role for suitably organized plasma rotation profiles, leading to suppression of MHD (magnetohydrodynamic) instabilities in magnetic confinement systems. The role of this effect in the problem of the Suydam and the m = 1 internal kink modes is elucidated, where m is the poloidal mode number.
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Anisotropy of thermal stresses in confined dusty plasmas is considered. It is shown that in a multi-component low-temperature plasma containing electrons, ions and dust, the complicated dependence of the ion viscosity on ion temperature gradients leads to a plasma equilibrium state with anisotropic pressure. This pressure anisotropy can be of the order of the ion pressure in some limiting cases, in which the ion Larmor radius or the ion mean free path are of the order of the characteristic length of the plasma nonuniformity. For a sufficiently large dust number density, they contribute to the plasma pressure anisotropy and to its spatial dependence. Currently, it is not yet clear whether this equilibrium state is stable or not. Under these conditions, some convective plasma flows can arise in confinement devices. Therefore, this question needs special consideration.
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The one-fluid magnetohydrodynamic (MHD) theory of magnetorotational instability (MRI) in an ideal plasma is presented. The theory predicts the possibility of MRI for arbitrary 0, where 0 is the ratio of the plasma pressure to the magnetic field pressure. The kinetic theory of MRI in a collisionless plasma is developed. It is demonstrated that as in the ideal MHD, MRI can occur in such a plasma for arbitrary P. The mechanism of MRI is discussed; it is shown that the instability appears because of a perturbed parallel electric field. The electrodynamic description of MRI is formulated under the assumption that the dispersion relation is expressed in terms of the permittivity tensor; general properties of this tensor are analyzed. It is shown to be separated into the nonrotational and rotational parts. With this in mind, the first step for incorporation of MRI into the general theory of plasma instabilities is taken. The rotation effects on Alfven waves are considered.
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Low-density lipoprotein (LDL) particles are the major cholesterol-carrying lipoprotein in the human circulation from the liver to peripheral tissues. High levels of LDL-Cholesterol (LDL-C) are known risk factor for the development of coronary artery disease (CAD). The most common approach to determine the LDLC in the clinical laboratory involves the Friedewald formula. However, in certain situations, this approach is inadequate. In this paper we report on the enhancement on the Europium emission band of Europium chlortetracycline complex (CTEu) in the presence of LDL. The emission intensity at 615 nm of the CTEu increases with increasing amounts of LDL. This phenomenon allowed us to propose a method to determine the LDL concentration in a sample composed by an aqueous solution of LDL. With this result we obtained LDL calibration curve, LOD (limit of detection) of 0.49 mg/mL and SD (standard deviation) of 0.003. We observed that CTEu complex provides a wider dynamic concentration-range for LDL determination than that from Eu-tetracycline previously. The averaged emission lifetimes of the CTEu and CTEu with LDL (1.5 mg/mL) complexes were measured as 15 and 46 Its, respectively. Study with some metallic interferents is presented. (C) 2010 Elsevier Inc. All rights reserved.
Resumo:
BACKGROUND Oxidized lipoproteins and antioxidized low-density lipoprotein (anti-oxLDL) antibodies (Abs) have been detected in plasma in response to blood pressure (BP) elevation, suggesting the participation of the adaptive immune system. Therefore, treatment of hypertension may act on the immune response by decreasing oxidation stimuli. However, this issue has not been addressed. Thus, we have here analyzed anti-oxLDL Abs in untreated (naive) hypertensive patients shortly after initiation of anti hypertensive therapeutic regimens. METHODS Titers of anti-oxLDL Abs were measured in subjects with recently diagnosed hypertension on stage 1 (n = 94), in primary prevention of coronary disease, with no other risk factors, and naive of anti hypertensive medication at entry. Subjects were randomly assigned to receive perindopril, hydrochlorothiazide (HCTZ), or indapamide (INDA) for 12 weeks, with additional perindopril if necessary to achieve BP control. Abs against copper-oxidized LDL were measured by enzyme-linked immunosorbent assay. RESULTS Twelve-week antihypertensive treatment reduced both office-based and 24-h ambulatory BP measurements (P < 0.0005). The decrease in BP was accompanied by reduction in thiobarbituric acid-reactive substances (TBARS) (P < 0.05), increase in anti-oxLDL Ab titers (P < 0.005), and improvement in flow-mediated dilation (FMD) (P < 0.0005), independently of treatment. Although BP was reduced, we observed favorable changes in anti-oxLDL titers and FMD. CONCLUSIONS We observed that anti-oxLDL Ab titers increase after antihypertensive therapy in primary prevention when achieving BP targets. Our results are in agreement with the concept that propensity to oxidation is increased by essential hypertension and anti-oxLDL Abs may be protective and potential biomarkers for the follow-up of hypertension treatment.
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Low-density lipoprotein (LDL) is known as `bad` cholesterol. If too much LDL circulates in the blood it can be retained in the walls of the arteries, causing atherosclerosis. In this paper we showed an alternative method to quantify LDL using the europium tetracycline (EuTc) indicator. The optical properties of the EuTc complex were investigated in aqueous solutions containing LDL. An enhancement was observed of the europium luminescence in the solutions with LDL compared those without the lipoprotein. A method to quantify the amount of LDL in a sample, based on EuTc enhanced luminescence, is proposed. The enhancement mechanism is also discussed. Copyright (C) 2009 John Wiley & Sons, Ltd.
Resumo:
Low-Density Lipoprotein (LDL), often known as ""bad cholesterol"" is one of the responsible to increase the risk of coronary arterial diseases. For this reason, the cholesterol present in the LDL particle has become one of the main parameters to be quantified in routine clinical diagnosis. A number of tools are available to assess LDL particles and estimate the cholesterol concentration in the blood. The most common methods to quantify the LDL in the plasma are the density gradient ultracentrifugation and nuclear magnetic resonance (NMR). However, these techniques require special equipments and can take a long time to provide the results. In this paper, we report on the increase of the Europium emission in Europium-oxytetracycline complex aqueous solutions in the presence of LDL. This increase is proportional to the LDL concentration in the solution. This phenomenum can be used to develop a method to quantify the number of LDL particles in a sample. A comparison between the performances of the oxytetracycline and the tetracycline in the complexes is also made.
Resumo:
Background: Recently, there has been an increasing in the impact of oral health on atherosclerosis and subsequent cardiovascular disease. The aim of this study is to investigate the association between chronic periodontitis and cardiovascular risk markers. Methods: Forty patients with periodontitis and 40 healthy gender-, body mass index-, and age-matched individuals were compared by measuring total cholesterol, high-density lipoprotein, low-density lipoprotein, triglycerides, levels of cytokines, antibodies against oxidized low-density lipoprotein, thiobarbituric acid reactive substances, total and differential white blood cell counts, and the non-linear index of refraction. Results: The levels of triglycerides and high-density lipoprotein in periodontitis patients were significantly higher and lower, respectively (P=0.002 and P=0.0126), compared to controls. Total cholesterol, low-density lipoprotein, and lipid peroxide levels were the same in both groups (P = 0.2943, P = 0.1284, and P = 0.067, respectively). Interleukin (IL)-6 and -8, antibodies against oxidized low-density lipoprotein, and leukocyte and neutrophil counts were significantly higher in periodontitis patients (P<0.05). The value of the non-linear index of refraction of low-density lipoprotein solutions was higher in the controls (P = 0.015) compared to individuals with periodontitis. Conclusion: Our results confirmed and further strengthened the suggested association between coronary artery disease and periodontitis. J Periodontol 2009;80:378-388.
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Neodymium based fluorescence presents several advantages in comparison to conventional rare earth or enzyme-substrate based fluorescence emitting sources (e.g.Tb, HRP). Based on this fact we have herein explored a Nd-based fluoroimmunoassay. We efficiently detected the presence of an oxidized low-density lipoprotein (oxLDL) in human plasma a well-known marker for cardiovascular diseases, which causes around 30% of deaths worldwide. Conventional fluoroimmunoassay uses time-resolved luminescence techniques, with detection in the visible range, to eliminate the fluorescence background from the biological specimens. By using an immunoassay based on functionalized Y(2)O(3):Nd(3+) nanoparticles, where the excitation and emission processes in the Nd(3+) ion occur in the near-infrared (NIR) region, we have succeeded in eliminating the interferences from the biological fluorescence background, avoiding the use of time-resolved techniques. This yields higher emission intensity from the Nd(3+)-nanolabels and efficient detection of anti-oxidized low-density lipoproteins (anti-oxLDL) by Y(2)O(3):Nd(3+)-antibody-antigen conjugation, leading to a novel biolabeling method. (C) 2010 Elsevier B.V. All rights reserved.
Resumo:
Banverket Trafik has a responsibility to make sure that the companies who traffic the Swedish railroad have the correct information about the status of the railroad. One of Banverket Trafiks information systems (Opera) presents the train’s actual position on a map and provides the user with physical information about the trains. Due to increasing demands on the information systems, Banverket Trafik needs to update the present system architecture in order to manage the increasing demands on map graphics and map functions. This paper analysis the information system Opera on the basis of theory and support of methods and discuss problems and demands for Opera. Further we investigate three GIS products to se if they meet the demands. Information about the products was gathered from both supplier and independent users to get a just picture of the products potentials. This paper comprises a suggestion of new system architecture that meet these needs. The suggested system architecture is capable of handling the map graphics and the map’s functions of more than one information system. Hopefully more than one information system will use the suggested system architecture as a map service.
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I dagens näringsliv är effektiv kommunikation och informationsutbyte mellan företag en förutsättning för verksamheten. Näringslivet utmärks av förändring; företag köps upp, företag slås samman, företag samarbetar i projektform. Behovet av att integrera varandras informationssystem står i paritet med ovanstående förändringar. Ett stort problem med systemintegration är variationsrikedomen mellan informationssystemen, beträffande teknisk plattform och programspråk. Webservices erbjuder metoder att enkelt integrera olika informationssystem med varandra.I rapporten beskrivs hur webservices implementeras och vilka tekniska komponenter som ingår, samt de fördelar som webservicetekniken ger. Uppdraget från Sogeti, Borlänge var att designa och implementera en prototyp, i vilken klientapplikationer i Java och VB.NET integreras med varandra genom webservices i respektive programspråk. För analys och design har metoden UML använts. Slutsatsen av rapporten är att Java och VB.NET kan kommunicera med varandra genom webserviceteknik. Dock är integrationen mellan de två programspråken inte okomplicerad. Detta leder till slutsatsen att webservicetekniken måste standardiseras för att få ordentligt genomslag som teknik för systemintegration mellan olika programspråk.
Resumo:
Pojkar och flickor ses ofta som två homogena och två var för sig ensamt verkande grupper. Det är uppsatsförfattarnas främsta mål att illustrera problemen vilka uppstår av ett oproblematiserat könskategoriserande och istället sätta individen i fokus. Syftet med denna uppsats är att, utifrån en fallstudie, problematisera kategorisering av människor inom forskning och låta könskategorisering agera exempel på en allmän problematik. Intresset hos uppsatsförfattarna ligger på att komma bort från en mekanisk förståelse av kön där målet med uppsatsen är insikt snarare än statisk analys.Frågorna vilka ställts för att konkretisera syftet är följande:-Hur agerar och reagerar läraren på olika störningsmoment i klassrummet?-I vilken utsträckning är pojkars och flickors aktivitet, enligt fallstudien, störningsmoment i klassrummet? -Är det i de undersökta klassrumssituationerna ett fåtal elever vilka tillkännager sig ofta eller är det många elever vilka tillkännager sig sällan?En fallstudie beslutades vara den mest lämpade metoden vid genomförandet av undersökningen och som metod inom fallstudien har uppsatsförfattarna använt sig av observationer. Observationerna vilka gjordes var så kallade strukturerade observationer. I vårt fall avses strukturerade observationer som observationer vilka utgår från i förväg utarbetade kategorier. Observationerna genomfördes i en nionde klass och en årskurs tre-klass på gymnasiet.Resultaten visade att flickorna som samlad kategori gav sig tillkänna i mycket högre utsträckning än pojkarna, men samtidigt gick det utläsa att det var några flickor vilka avsevärt höjde medelvärdet för könsgruppen. Samma förhållande förelåg hos pojkarna, där det var ett fåtal vilka tillkännagav sig i mycket högre utsträckning än resterande. Detta innebar att de elever vilka aldrig eller sällan gav sig tillkänna med rätt icke torde kategoriseras in under en grupp för vilken resultatet av granskningen för dem inte är karakteristiskt. I de undersökta och observerade klasserna visade det sig att 10 % av eleverna stod för 60 % av den totala mängd störande tillkännagivanden i klassrumssituationerna. Detta innebär att övriga elever icke bör beskyllas för att ha bidragit till en eventuell störning i klassrummet. Det är sålunda rimligt att sluta sig till att det finns faror med kategorisering av människor, då elever i negativ mening kan påverkas både socialt och pedagogiskt. Dessa slutsatser går även att applicera på och dra slutsatser kring kategorisering av människor i allmänhet.