X-ray, Electrolytic Conductance, and Dielectric Studies of Bile Salt Micellar Aggregates

Langmuir ◽  
2000 ◽  
Vol 16 (26) ◽  
pp. 10436-10443 ◽  
Author(s):  
Adalberto Bonincontro ◽  
Angelo Antonio D'Archivio ◽  
Luciano Galantini ◽  
Edoardo Giglio ◽  
Francesco Punzo
Keyword(s):  
Bile Salt ◽  
Dielectric Studies ◽  
Electrolytic Conductance ◽  
X Ray ◽  
Micellar Aggregates

scholarly journals Термодинамические свойства оксипентафторида ванадия (IV), (NH-=SUB=-4-=/SUB=-)-=SUB=-3-=/SUB=-VOF-=SUB=-5-=/SUB=-

2020 ◽  
Vol 62 (7) ◽  
pp. 1123
Author(s):  
Е.В. Богданов ◽  
Е.И. Погорельцев ◽  
А.В. Карташев ◽  
М.В. Горев ◽  
М.С. Молокеев ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Photoelectron Spectroscopy ◽  
Single Phase ◽  
Dielectric Studies ◽  
X Ray Diffraction ◽  
X Ray ◽  
Limits Of Stability ◽  
Three Phase ◽  
Temperature Dependences ◽  
Spectroscopy Studies

Abstract The (NH_4)_3VOF_5 crystals have been synthesized and their homogeneity and single-phase structure has been established by the X-ray diffraction, energy dispersive spectroscopy, and X-ray photoelectron spectroscopy studies. The investigations of the temperature dependences of specific heat, entropy, strain, and pressure susceptibility show the occurrence of three phase transitions caused by the structural transformations in the (NH_4)_3VOF_5 crystals. The T – p phase diagram shows the temperature limits of stability of the crystalline phases implemented in (NH_4)_3VOF_5. The optical and dielectric studies disclose the ferroelastic nature of the phase transitions. An analysis of the experimental data together with the data on the isostructural (NH_4)_3VO_2F_4 crystal makes it possible to distinguish the physical properties of oxyfluorides containing vanadium of different valences (IV and V).

scholarly journals Dielectric and Raman studies of Ba0.06(Na1/2Bi1/2)0.94TiO3–NaNbO3 ceramics

2016 ◽  
Vol 34 (2) ◽  
pp. 437-445 ◽  
Author(s):  
Sumit K. Roy ◽  
S. Chaudhuri ◽  
R.K. Kotnala ◽  
D.K. Singh ◽  
B.P. Singh ◽  
...  
Keyword(s):  
Single Phase ◽  
Solid State Reaction Method ◽  
Lead Free ◽  
Orthorhombic Symmetry ◽  
Dielectric Studies ◽  
X Ray Diffraction ◽  
Reaction Method ◽  
X Ray ◽  
New Phase ◽  
Diffusivity Parameter

AbstractIn this work the X-ray diffraction, scanning electron microscopy, Raman and dielectric studies of lead free perovskite (1 – x)Ba0.06(Na1/2Bi1/2)0.94TiO3–xNaNbO3 (0 ⩽ x ⩽ 1.0) ceramics, prepared using a standard solid state reaction method, were investigated. X-ray diffraction studies of all the ceramics suggested the formation of single phase with crystal structure transforming from rhombohedral-tetragonal to orthorhombic symmetry with the increase in NaNbO3 content. Raman spectra also confirmed the formation of solid solution without any new phase. Dielectric studies showed that the phase transition is of diffusive character and diffusivity parameter decreases with increasing NaNbO3 content. The compositional fluctuation was considered to be the main cause of diffusivity.

X-ray, Mössbauer, and dielectric studies of the Co1 − x Ni x Cr2O4 ceramic system

2013 ◽  
Vol 77 (6) ◽  
pp. 663-667 ◽  
Author(s):  
V. M. Cherepanov ◽  
A. A. Bush ◽  
V. Ya. Shkuratov ◽  
K. E. Kamentsev
Keyword(s):  
Dielectric Studies ◽  
Ceramic System ◽  
X Ray

scholarly journals Growth and Characterization of Pure and Doped L-Alanine Tartrate Single Crystals

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
K. Rajesh ◽  
B. Milton Boaz ◽  
P. Praveen Kumar
Keyword(s):  
Single Crystals ◽  
Vickers Microhardness ◽  
Diffraction Method ◽  
Dielectric Studies ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Parameters ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

Single crystals of pure and Lanthanum doped L-Alanine Tartrate were grown by slow evaporation method. The cell parameters were determined using single crystal X-ray diffraction method. To improve the physical properties of the LAT crystal, Lanthanum dopant was added by 2 mol%. ICP studies confirm the presence of Lanthanum in the grown LAT crystal. Transparency range of the crystal was determined using UV-VIS-NIR spectrophotometer. The functional groups of pure and doped LAT crystals were analyzed by FT-IR spectroscopy. Using Vickers microhardness tester, mechanical strength of the material was found. Dielectric studies of pure and doped LAT single crystals were carried out. The doped LAT crystal is found to have efficiency higher than that of pure LAT crystal.

X-Ray and Dielectric Studies of the Phase Transitions in Pb(Yb1/2Nb1/2)O3-PbTiO3Ceramics

1995 ◽  
Vol 34 (Part 1, No. 9B) ◽  
pp. 5449-5452 ◽  
Author(s):  
Hoon Lim ◽  
Hyo Jin Kim ◽  
Woong Kil Choo
Keyword(s):  
Phase Transitions ◽  
Dielectric Studies ◽  
X Ray

scholarly journals Influence of cation order on the dielectric properties of (1 – x)Pb(Sc0:5Nb0:5)O3-xPb(Yb0:5Nb0:5)O3 ceramics

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Barbara Garbarz-Glos ◽  
Wojciech Bąk ◽  
Maija Antonova ◽  
Anna Kalvane ◽  
Czesław Kajtoch ◽  
...  
Keyword(s):  
Relaxor Ferroelectric ◽  
Solid State Reactions ◽  
Dielectric Studies ◽  
X Ray Diffraction ◽  
X Ray ◽  
Broadband Dielectric Spectroscopy ◽  
Cation Order ◽  
Ceramic Samples ◽  
All Ceramic ◽  
Diffuse Phase

AbstractCeramic lead niobates and their solid solutions (1 – x)Pb(Sc0:5Nb0:5)O3 – xPb(Yb0:5Nb0:5)O3 were synthesized by solid state reactions from oxides. The structure of investigated samples was characterized by X-ray diffraction (XRD). Dielectric studies of the ceramics were performed by means of broadband dielectric spectroscopy at the temperature ranging from 600 K to 140 K. For all ceramic samples a diffuse phase transition as well as relaxor ferroelectric behavior were observed.

Interconversions of lipid aggregates in rat and model bile

1991 ◽  
Vol 260 (1) ◽  
pp. G70-G79 ◽  
Author(s):  
T. E. Little ◽  
S. P. Lee ◽  
H. Madani ◽  
E. W. Kaler ◽  
K. Chinn
Keyword(s):  
Bile Salt ◽  
Total Lipid ◽  
Mixed Micelles ◽  
Relative Proportion ◽  
Gel Permeation Chromatography ◽  
Cholesterol Content ◽  
Biliary Fistula ◽  
Micellar Aggregates ◽  
Lipid Aggregates ◽  
Model Bile

The dynamic interchange of cholesterol and the phase transition between nonmicellar and micellar aggregates in rat and model bile were characterized with gel-permeation chromatography, quasi-elastic light scattering, turbidity measurements, and by radiolabeling lipid aggregates in bile. Cholesterol partitioned into either the micellar or nonmicellar phases independent of the lipid aggregate structure. In model bile, increasing bile salt concentrations led to a decrease in the relative proportion of nonmicellar aggregates beginning at 5 mM taurocholate (TC), while the relative cholesterol content of the nonmicellar fraction increased from 1.0 to 2.7 +/- 2.0 (means +/- SD). In rats, creation of a biliary fistula resulted in a decrease of bile salts from 41 to 4 mM. Mixed micelles increased from 25 to 120 A in radius, while nonmicellar aggregates increased from 180 to 800 A in radius. Addition of TC to model bile (cholesterol:lecithin = 1:1) vesicles with total lipid concentrations less than 7 mM yielded a progressive shift of vesicles (450 A) to mixed micelles (30 A). For mixtures with higher total lipid concentrations, addition of TC promoted substantial vesicle aggregation and resulted in formation of a third phase containing lipid aggregates larger in size than the initial vesicles. These results suggest that rapid exchange of cholesterol occurs in bile and that significant remodeling of vesicles can occur. These alterations in vesicles include both enrichment in cholesterol content and formation of larger aggregates during increases in bile salt concentration.

Distribution and partitioning of cholesterol and beta-sitosterol in micellar bile salt solutions

1987 ◽  
Vol 253 (3) ◽  
pp. G268-G273
Author(s):  
K. Chijiiwa
Keyword(s):  
Bile Salt ◽  
Aqueous Phase ◽  
Brush Border Membrane ◽  
Monomer Concentration ◽  
Direct Interaction ◽  
Similar Amount ◽  
Micellar Solutions ◽  
Salt Solutions ◽  
Micellar Aggregates ◽  
Everted Jejunal Sacs

The distribution of cholesterol and beta-sitosterol in micellar bile salt solutions was studied using an ultrafiltration technique to separate micellar aggregates from monomers present in the intermicellar aqueous phase. The partitioning and the rates of influx across the brush-border membrane of these two sterols from micellar solutions were determined using polyethylene discs and everted jejunal sacs, respectively. Micellar solubilities of cholesterol and beta-sitosterol were not significantly different, whereas the monomer concentration of beta-sitosterol in the intermicellar aqueous phase was significantly lower than that of cholesterol [0.21 +/- 0.02 microM for beta-sitosterol and 25.0 +/- 2.71 (SE) microM for cholesterol, P less than 0.001]. There was no difference in the partitioning nor was there a difference in the rates of influx between cholesterol and beta-sitosterol from micellar solutions containing a similar amount of the two sterols. It is concluded that monomer concentration of beta-sitosterol in the intermicellar aqueous phase is extremely low compared with that of cholesterol, but their partitioning and rates of influx across the membrane are similar. This is primarily attributable to a much higher membrane/monomer partition coefficient of beta-sitosterol than cholesterol and to a direct interaction between micelle and membrane.

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