Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 30 for “"gel phase"”.
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Gel phase transition and molecular recognition
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 1997.
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Microscopic and Spectroscopic Investigation Of: I. Copper-Additive Systems in Electroplating Bath. II. Supported Phospholipid Bilayer Systems
Second, soft imaging mode of AFM and phase modulated ellipsometry are used to observe the phase transition process of supported lipid bilayer systems with and without the influence of other macromolecules. Addition of a weak polyelectrolyte, poly(methacrylic acid) (PMA), to a supported phospholipid …
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Probing Biological Systems at the Single Molecule Level: Studies of the Homophilic Binding of the Neural Cell Adhesion Molecule (Ncam) and Phase Dependent Lipid Anchorage Strength
… the anchorage strength of lipids in fluid versus gel lipid layers was probed to determine how temperature affects the adhesion properties between adjacent lipid molecules. From this study we have shown that it takes almost three times the force to extract a lipid from a gel phase lipid layer as …
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Effects of varying ethanol and water concentrations as a gold nanoparticle gel solvent
… contain the nanoparticles is that of a chemical gel. The nanoparticles for use in these studies do not require a polymer base in order to form a gel phase. However, a concrete analysis of the transition temperature between the gel and liquid phases had yet to be performed. The work performed in …
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Phase Behavior, Fluid Structure, and Slow Dynamics in Polymer -Colloid Mixtures: Novel Liquid State Theory and Its Applications
… over length scales of D-10D in the fluid phase. The theory captures the non-monotonic changes in the local cage order parameter S(k* ≈ 7 D) with increasing polymer concentrations. Accurate, no adjustable parameter predictions of the fluid structure are combined with a single particle …
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Interactions of Inorganic Mercury and Inorganic Cadmium with Biomimetic and Complex Biological Membranes and their Influence on Membrane Packing and Size
… The effect of these metals on the fluidity and phase transition (Tm) of biomimetic and polar extract membranes was investigated using Laurdan Generalized Polarization (GP) and Dynamic Light Scattering (DLS). Hg2+ and Cd2+ electrostatically target and induce rigidity in membranes containing …
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Local Viscosity and Environment on the Nanometer Scale
… of the pluronic polymer which shows sol to gel phase transition was compared to the bulk viscosity near the transition temperature and the local viscosity change is much smaller than bulk viscosity. With the combination of dielectric measurement, the motion of polymer chains and local …
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NMR studies of bio-systems at high pressure
… the pressure range from 1 bar to 5 kbar. The phase diagram was constructed, structure and dynamics of the bilayers were examined. The pressure dependence of the dynamic and conformational characteristics were studied using $\sp{31}$P NMR spectroscopy at 50$\sp\circ$C over the pressure range …
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Phase Behavior, Structure, and Properties of Colloidal Microsphere-Nanoparticle Mixtures
The phase behavior, structure, and properties of binary mixtures of negligibly charged colloidal microspheres were studied for two size ratios of 95 and 197 at pH = 1.5. In the absence of nanoparticle additions, the system spontaneously assembled into a colloidal gel whose strength increased with …
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Spatial correlation of lipid phase fluctuations in model membranes studied with two-photon fluorescence microscopy
The temporal dynamics of lipid phase fluctuations and the spatial organization of model lipid membranes was studied using Two-photon excitation fluorescence microscopy. Lipid membranes of different composition were reconstituted in Giant Unilamellar Vesicles (GUVs) and labeled with the environment …
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Microstructure and Mechanics of Poly(n-Isopropylacrylamide) Based Responsive Fluids
… swellable poly(N-isopropylacrylamide) microgels has been studied. The strength and range of the colloidal interparticle interactions are manipulated by controlling the temperature dependent size of the poly( N-isopropylacrylamide) microgels. We first characterize the temperature and …
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The Tansmembrane Associations of HIV-1 Vpu and its Human Targets
… role of the lipid bilayer, specifically lipid phase and hydrophobic thickness, on TM domain assembly within the Vpu-target system. We show that thicker membranes and gel phase lipids non-specifically promote associations of Vpu and its targets without affecting secondary structure. The …
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Origin and development of internal stresses during polymerization of composite resins
… process. Two stages can be distinguished: pre-gel and post-gel. Because stiffness develops after the gel-point, only the post-gel phase plays a role in the development of polymerization stresses. An enhanced strain gage method is developed to determine the dynamic post-gel linear contraction. …
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Biphasic Nanoparticle Inks for Direct Write Assembly of Three-Dimensional Periodic Structures
… between repulsive glasses and attractive gels, yet the scaling of their elastic properties with respect to volume fraction is dominated by the gel phase. By contrast, their compressive yield stress exhibits a volume fraction dependence that varies systematically between that observed for …
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The Influence of Amorphous, Sub-Micrometer Silica Particles in Cement Pastes and Mortars with Very Low Water-to-Cement Ratios (Ultra-High Performance Concrete)
… pozzolanic reaction to calcium–silicate–hydrate phases (C–S–H phases) and/or due to a heterogeneous nucleation of C–S–H phases from alite hydration on silica surfaces (seeding effect). Herein, the influence of the reactivity of silica has been rarely considered. Furthermore, the incorporation of …
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Intermediate phases of surfactant - water mixtures
Intermediate phases in two non-ionic polyoxyethylene surfactantiD20 systems - nonaethylene glycol mono (1 1-oxa-14,18,22,26-tetramethylheptacosyl) ether (C30E09) and hexaethylene glycol n-hexadecyl ether (C15E05) have been studied. Both systems have a rhombohedral mesh phase with the space group …
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Morphology-Property Relationships in Polymers: Poly(vinyl Chloride) and Polybutene-1 (Polyvinyl)
… and type of crystals. Four PVC/solvent gels (PVC/Dimethyl phthalate, PVC/Bromobenzene, PVC/Dioxane and PVC/Dichloroethane) were characterized. The crystal melting temperatures in the gels were found to be different from the gel melting temperatures. The melting enthalpy of these gels are …
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Structure and dynamics of plant cell walls and membrane peptides from solid-state NMR
… arrangement of these macromolecules has been largely elusive due to the lack of high-resolution and sitespecific characterization techniques. Here, we introduce SSNMR to investigate the interactions of macromolecules in ¹³C-labeled plant primary cell walls with minimal treatment. Our …
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Corticosteroid-Encapsulated Nanoparticles in Thermoreversible Gels for the Amelioration of Choroidal Neovascularization in Age-Related Macular Degeneration
… (PLGA-PEG) nanoparticles in thermoreversible gels as localized sustained intraocular drug delivery. We prepared stable and reproducible corticosteroid-encapsulated nanoparticles in thermoreversible gels to inhibit vascular endothelial growth factor (VEGF) overexpression characteristic of …
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Model Membranes Study the Lipid-Reactivity of HIV-1 Antibodies and Vaccine Antigen
… Next, we focused on mimicking the lipid phase organization (i.e., domain formation) of native membranes by using supported lipid bilayers (SLBs). We used simple SLB compositions to model the liquid-disordered (Ld) and gel phases. To model the HIV-1 envelope, we used a complex SLB …
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