Spelling suggestions: "subject:"fluidity"" "subject:"tluidity""
21 |
Membrane fluidity and fatty acids in multiple sclerosis patientsHon, Gloudina Maria January 2009 (has links)
Thesis (DTech (Biomedical Technology))--Cape Peninsula University of Technology, 2009 / Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system
(CNS), which leads to neuronal demyelination, and eventually to oligodendrocyte and axon
loss, with subsequent lesion formation. The wide distribution of lesions in the CNS results in
a variety of clinical features, such as cognitive impairment, vertigo, spasticity, ataxia tremors,
progressive quadriparesis, pain and depression. Currently no cure exists for CNS disorders,
resulting in a decline in quality of life, and an economic burden on society. Metabolic
disturbances, especially lipid metabolic abnormalities, have been implicated in the
development of MS. Although the disease cannot be cured, disease-modifiers, such as
interferon beta, glatiramer acetate and mitoxantrone, as well as fatty acid supplementatlon
have been used to delay the progression of the disease. Membrane fatty acids are
precursors for mediators of inflammation, the eicosanoids, which are produced soon after
stimulation and which regulate a number of inflammatory effects, such as the induction of
fever, vasodilation and production of macrophage- and Iymphocyte-derived cytokines.
Eicosanoids, in contrast to their fatty acid precursors, have a short half-life and are therefore
difficult to measure.
The objective in the present study was to determine the role of fatty acids from South African
MS patients, by measuring the fatty acid composition of phosphatidylcholine (PC),
phosphatidylethanolamine (PE), phosphatidylserine (PS), phosphatidylinositol (PI) and
sphingomyelin (SM) phospholipids in the plasma, red blood cell (RBC) and peripheral blood
mononuclear cell (PBMC) membranes and correlate abnormalities with the neurological
outcome as measured by the Kurtzke Expanded Disability Status Scale (EDSS) and
inflammation assessed by C-reactive protein (CRP). A second objective was to establish
whether possible changes in membrane lipids (phospholipids, fatty acids and cholesterol)
would have an effect on membrane fluidity, and whether this would correlate with the EDSS
and CRP.
The plasma, RBC and PBMC membrane lipid composition from 31 white female patients with
MS and 30 age- and gender-matched control subjects were assessed. Fatty acids were
quanflfied by gas chromatography (GC), phospholipids by colorimetric and cholesterol by
enzymatic assays. Membrane fluidity, as measured by the membrane lipid composition, was
calculated, using previously established formulae, and includes the following: the saturated
nature of the membrane was measured by the phospholipid PC+PS/PE+PS ratio, fluidity and
permeability were measured by the cholesterol concentratlon and the cholesterol to total
phospholipid ratio and membrane deformability was measured by the phospholipid PE to PS
ratio. Membrane fluidity was also measured by the ordered-erystalline-phase to liquidcrystalline-
phase lipid composition, which correlates with the phospholipid PE to PC ratio.
The membrane saturated (SATS) to polyunsaturated fatty acid (PUFA) ratio was further used
as an indication- of the fluidity status of the membranes. CRP was measured in all
participants using a Beckman nephelometer.
In MS, the n-6 fatty acids, particularly C18:2n-6, C20:4n-6 and C22:4n-6, were significantly
decreased in plasma, RBC and/or PBMC membranes. In addition, the relationship between
C20:3n-6 and C20:4n-6 showed a metabolic disturbance in both RBC and PBMC
membranes from patients with MS, as compared to the control group. C20:4n-6 showed
significant inverse correlations with the EDSS and CRP in MS patients, indicating that loss of
these fatty acids from membranes correlated with higher disability as well as with increased
inflammation. There were significant increases in free fatty acids C18:2n-6 and C20:4n-6 in
plasma from MS patients. Saturated fatty acids, SM C14:0 and PI C22:0 were significantly
increased in PBMC membranes from MS patients, and SM C14:0, C16:0 and C20:0 showed
inverse correlations with the Functional System Scores. In contrast, the longer-ehain SATS,
C22:0 and C24:0 showed positive correlations with the Functional System Scores. Red blood
cell membrane fluidity as measured by the SATS to PUFA ratio was significantly higher in
patients than in controls. In patients with CRP ~ 5.00 Ilglml the ratio showed significant
inverse correlation with disease outcome. The saturated nature correlated positively, whilst
the .ordered-erystalline-phase to liquid-crystalline-phase lipid ratio correlated inversely with
the Functional System Scores.
In this study it was consistently shown that C20:4n-6, or its precursor and elongation
products, C18:2n-6 and C22:4n-6 respectively, was lower in plasma, RBC and/or PBMC
membranes from MS patients. Red blood cells lack the desaturase enzymes and depend on
fatty acids sourced from the plasma. Therefore, lower C20:4n-6 in the RBC membranes from
MS patients may be due to depleted plasma stores, or an indication of an increased demand
of this fatty acid elsewhere. Furthermore, this study has demonstrated that lower RBC
C20:4n-6, with an increase in plasma FFA C20:4n6, resulted in worse disease outcome,
perhaps due to the pro-inflammatory effect of eicosanoid production. This. study also
characterized the specific SATS, that is, longer-ehain SATS that may increase the risk of
developing MS, as higher shorter-ehain SATS, C14:0 and C16:0 reflected better disease
outcome, demonstrated by the inverse correlation with the EDSS and FSS. Lastly, this study
has shown that in the presence of uncontrolled inflammation such as in MS, the altered lipid
composition indirectly compromised cell membrane, structure and fluidity, and thereby
contributed to the disease progression in MS patients.
|
22 |
Ver através : da pintura e outras incertezasJob, Renata Corrêa January 2011 (has links)
A pintura como geradora da reflexão sobre as imagens produzidas: da sutileza e da dúvida. Partindo do suporte, tomar o material como determinante de uma visualidade delicada, de vazios, escorridos, vapores e condensações. Imagens que resistem em se mostrar, propostas tímidas, como pontuação de delicadeza em um cotidiano saturado de imagens. O corpo como medida: da ação artística e da fluidez que dela resulta. / Painting as a reflection on generating images produced: the subtlety and doubt. Starting from the support, taking the material as determinant of a visual delicate, empty, drained, vapors and condensations. Images that resist showing off, timid proposals, as score of delicacy on a daily saturated images. The body as measure: from the artistic action and fluidity that it brings.
|
23 |
Sustainable ultra-high performance concrete with incorporating mineral admixtures: Workability, mechanical property and durability under freeze-thaw cyclesGe, W., Liu, W., Ashour, Ashraf, Zhang, z., Li, W., Jiang, H., Sun, C., Qiu, L., Yao, S., Lu, W., Liu, Y. 13 September 2023 (has links)
Yes / This paper evaluates the influence of mineral admixtures partially replacing cement, sea sand replacing quartz, sea water replacing fresh water on ultra-high performance concrete (UHPC). The fluidity and mechanical properties were studied. Besides, the impermeability, chloride resistance and freeze-thaw resistance were investigated. Failure modes, scanning electron microscope (SEM) analysis, mass loss, relative dynamic modulus of elasticity and mechanical properties of UHPCs after freeze-thaw cycles were conducted. The results showed the fluidity of UHPC paste gradually increases with the improvement of water-binder ratio. It is recommended that the water-binder ratio of UHPC be set at 0.19. The fluidity also increases with the improvement of the content of slag, fly ash and water reducer, but decreases with the improvement of silica fume content. The flexural and compressive strengths of UHPC enhance with the improvement of the content of silica fume, but reduce with the improvement of the content of fly ash and slag. The UHPCs made of quartz sand, river sand and sea sand, all, achieve a high strength. UHPCs prepared at standard curing conditions, with or without steel fibers, mixed by artificial seawater and made of sea sand, exhibited excellent impermeability and chloride resistance. The frost resistant grade of all UHPC specimens prepared by standard curing are greater than F500 exhibiting excellent freeze-thaw resistance and sustainability.
|
24 |
Fundamentals and Applications of Enhanced fluidity Liquids for Intact Protein Mass Spectrometry AnalysisSylvester, O'Donnell Pwanahakai January 2022 (has links)
No description available.
|
25 |
Second Life, Second ChanceBeattie, Jessica K. 08 1900 (has links)
This is a collection of two stories, one fiction and one non-fiction, in communication with one another. Both stories explore how trauma can transform a life. In "Tabula Rasa," Mena is unable to recall her past after being beaten and left for dead. She must choose whether to uncover her past or forget it and move forward with her life. Set in a town run by witches, Mena learns that both choices are dangerous. In "Eternal Second," the narrator recounts the aftermath of her husband's suicide. She explores how trauma invades all aspects of her life. In both stories, women must navigate a new life created by the destruction of the old one.
|
26 |
Epithelial Ion Transport and Gastrointestinal Fluid HomeostasisBradford, Emily M. January 2009 (has links)
No description available.
|
27 |
On Inverses and Linear IndependenceMoore, Jeremy S. 26 July 2011 (has links)
No description available.
|
28 |
Understanding the Fluidity of Gender and Sexual Orientation: Developing Culturally Competence Nursing StudentsNovotny, Beth 09 March 2020 (has links)
No description available.
|
29 |
Fluidity in SpaceYang, Ning 09 October 2018 (has links)
Architecture is the will of an epoch translated into space.
-Mies van der Rohe
Architectural space is directly related to enclosure. When inside and outside are dynamically brought together, or when a series of enclosures dymamically collaborate, perhaps one could speaks of fluid space.
Inspired by clouds and water streams - objects in constantly changing form, the architecture in the project seeks to formlate space that could flow similarly but is grounded in the context of a contemporary urban environment. / Master of Architecture
|
30 |
Writing materiality into management and organization studies through and with Luce IrigarayFotaki, M., Metcalfe, B.D., Harding, Nancy H. 04 July 2014 (has links)
Yes / There is increasing recognition in management and organization studies of the
importance of materiality as an aspect of discourse, while the neglect of materiality in
post-structuralist management and organization theory is currently the subject of much
discussion. This article argues that this turn to materiality may further embed gender
discrimination. We draw on Luce Irigaray’s work to highlight the dangers inherent in
masculine discourses of materiality. We discuss Irigaray’s identification of how language
and discourse elevate the masculine over the feminine so as to offer insights into ways
of changing organizational language and discourses so that more beneficial, ethicallyfounded
identities, relationships and practices can emerge. We thus stress a political
intent that aims to liberate women and men from phallogocentrism. We finally take
forward Irigaray’s ideas to develop a feminist écriture of/for organization studies that
points towards ways of writing from the body. The article thus not only discusses how
inequalities may be embedded within the material turn, but it also provides a strategy
that enriches the possibilities of overcoming them from within.
|
Page generated in 0.0473 seconds