The Effect of Sodium Dopants on Calcium Polyphosphate Biomaterials

2007 ◽  
Vol 361-363 ◽  
pp. 281-284
Author(s):  
Judy Ue ◽  
R.M. Pilliar ◽  
R.A. Kandel ◽  
Tom W. Coyle ◽  
M.D. Grynpas
Keyword(s):  
Phase Transition ◽  
Thermal Analysis ◽  
Sodium Carbonate ◽  
Sodium Phosphate ◽  
Dopant Concentration ◽  
Neck Formation ◽  
Calcium Polyphosphate ◽  
Phase Transition Temperatures ◽  
Different Temperatures ◽  
Dopant Source

Sodium-doped CPP was synthesized using three dopant sources (sodium carbonate, sodium hydroxide and sodium phosphate). These materials were analyzed by XRD to determine phase composition and by differential thermal analysis to identify phase transition temperatures. Sintering of resulting glass powders showed that both dopant source and dopant concentration affects sinter neck formation and crystallinity. The open porosity of sodium phosphate and sodium carbonate doped samples at 0.1 Na2O/CaO sintered at different temperatures changed significantly. Crystallization of the construct during sintering was noted at temperatures lower than expected.

Temperature dependence of dipalmitoyl phosphatidylcholine monolayer stability

1981 ◽  
Vol 51 (5) ◽  
pp. 1108-1114 ◽  
Author(s):  
J. Goerke ◽  
J. Gonzales
Keyword(s):  
Phase Transition ◽  
Lung Surfactant ◽  
Principal Component ◽  
Water Interface ◽  
Dipalmitoyl Phosphatidylcholine ◽  
Phase Transition Temperatures ◽  
Air Water Interface ◽  
Different Temperatures ◽  
Monolayer Stability ◽  
Isolated Rat

Dipalmitoyl phosphatidylcholine is the principal component of lung surfactant, and knowledge of its behavior as a film spread at the air-water interface is essential for understanding how lung surfactant itself works. We therefore studied the collapse rates of very low surface tension air-water monolayers of dipalmitoyl, dimyristoyl, and palmitoyl-myristoyl phosphatidylcholines at different temperatures. In each case we found that the monolayers abruptly became unstable at temperature 3–4 degree C above their bulk lipid-water phase transition temperatures (Tc). This accords with a comparable increase in Tc occurring in bulk systems subjected to high pressure. These findings are also consistent with the behavior of isolated rat lungs, which have been found to require higher transmural pressures to maintain a given volume on deflation when kept at temperature above the Tc of dipalmitoyl phosphatidylcholine.

The effect of lipid composition, bilayer phase and temperature on the uptake of hematoporphyrin by liposomal membranes

2007 ◽  
Vol 11 (08) ◽  
pp. 577-585 ◽  
Author(s):  
Refael Minnes ◽  
Hana Weitman ◽  
Benjamin Ehrenberg
Keyword(s):  
Phase Transition ◽  
Lipid Vesicles ◽  
Order Parameters ◽  
Effect Of Temperature ◽  
Dramatic Decrease ◽  
Phase Transition Temperatures ◽  
Different Temperatures ◽  
Liposomal Membranes ◽  
Gel Phase ◽  
Different Order

In this study we investigated, spectroscopically, the binding of hematoporphyrin (HP) to non-charged lipid vesicles as a function of temperature and the molecular structure of the phospholipid. The temperature dependence of partitioning was employed to evaluate the thermodynamic parameters of the process. We studied the binding of HP to liposomes composed of different phospholipids: natural lecithin and three chemically defined phosphatidylcholines: dimiristoyl-phosphatidylcholine (DMPC), 1-palmitoyl-2-myristoyl-phosphatidylcholine (PMPC) and 1-stearoyl-2-myristoyl-phosphatidylcholine (SMPC), at different temperatures. The last three lipids differ only in the length of the fatty acid on 1 position of the glycerol backbone. Consequently, they have different phase transition temperatures and different order parameters. For SMPC, PMPC and DMPC, we checked the effect of temperatures above and below the phase transition while for lecithin, whose phase transition temperature is well below 0 °C, only temperatures above the phase transition could be tested. A very distinct effect of the phase transition on the binding constant was observed. Below this temperature a dramatic decrease in the binding was observed as the temperature was increased. Above the phase transition, the effect of temperature declined and the changes were minor compared to the changes observed when the bilayers undergo the solid-gel phase transition. Differences in HP binding to the various bilayers were attributed to the differences in the order parameters of DMPC, PMPC, SMPC and lecithin bilayers.

Liquid Crystals in Binary Systems of Lead Decanoate with Zinc or Cadmium Decanoate

2000 ◽  
Vol 55 (11-12) ◽  
pp. 899-901
Author(s):  
Mirnaya T. A. ◽  
L. S. Sudovtsova ◽  
G. G. Yaremchuk
Keyword(s):  
Phase Transition ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Room Temperature ◽  
Binary Systems ◽  
Crystal Formation ◽  
Liquid Region ◽  
Polarization Microscopy ◽  
Isotropic Liquid ◽  
Phase Transition Temperatures

Abstract The phase transition temperatures were determined by differential thermal analysis and hot stage polarization microscopy between room temperature and the isotropic liquid region for the binary systems of lead (II) decanoate with zinc (II) or cadmium (II) decanoate. The boundaries of the liquid crystal formation in these systems were found.

Electrical Conductivity and Phase Transition Studies in the ZrO2-CdO System

2012 ◽  
Vol 329 ◽  
pp. 147-157
Author(s):  
Saba Beg ◽  
Sadaf Haneefaa
Keyword(s):  
Phase Transition ◽  
Electrical Conductivity ◽  
Dopant Concentration ◽  
Low Frequency ◽  
Spectral Studies ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
Different Temperatures ◽  
Oxide Ions ◽  
Transition Studies

The Solid Solution of ZrO2: Cdo Was Prepared by the Conventional Solid-State Reaction. Effect of Dopant Concentration on the Electrical Conductivity of ZrO2Was Studied for Different Compositions at Different Temperatures. the Conductivity Increases with the Addition of Cdo due to the Migration of Vacancies. the Conductivity Increases with Rise in Temperature up to 180°C and Thereby Decreases due to the Collapse of Fluorite Framework. A Second Rise in Conductivity at High Temperature beyond 460°C Is due to the Phase Transition of ZrO2from Monoclinic to Tetragonal. DSC, X Ray Powder Diffraction, Impedance Measurements and FTIR Spectral Studies Were Carried Out for Confirming the Doping Effect and Transitions in ZrO2. the Addition of Cdo to Zro2 Shifted the Phase Transition of ZrO2to Higher Temperatures as Confirmed by the DSC Results. the Occurrence of Single Semi Circle with a Low Frequency Inclined Spike Indicates that the Conductivity Is Mainly due to the Movement of Oxide Ions.

scholarly journals Phase Equilibria in the Bi-In-Sn-Zn System. Thermal Analysis vs. Calculations

2017 ◽  
Vol 62 (4) ◽  
pp. 1945-1955
Author(s):  
A. Dębski ◽  
B. Onderka ◽  
W. Gąsior ◽  
T. Gancarz
Keyword(s):  
Phase Transition ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Graphite Crucible ◽  
Temperature Data ◽  
Liquid Alloys ◽  
Constant Ratio ◽  
Phase Transition Temperatures ◽  
Dta Studies ◽  
Good Agreement

AbstractWith the use of the differential thermal analysis (DTA), studies of the phase transitions were conducted for 90 of alloys from the quaternary Bi-In-Sn-Zn system and for the constant ratio of Bi:In and Bi:Sn. The studies were conducted for the alloys prepared from the purity metals (Bi, In, Sn, Zn = 99.999 mas. %) by way of melting in a graphite crucible in a glove-box filled with Ar, in which the impurities level was less than 0.1 ppm. After melting and thorough mixing, the liquid alloys were poured out into a graphite test mold. The phase transition temperature data obtained from the DTA investigations were next confronted with those determined from the calculations based on the binary and ternary optimized thermodynamic parameters available in the literature. It was found that the experimental and the calculated phase transition temperatures were in good agreement.

The structure of membranes and membrane proteins embedded in amorphous ice

1992 ◽  
Vol 50 (1) ◽  
pp. 432-433
Author(s):  
Uwe Lücken ◽  
Joachim Jäger
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Membrane Proteins ◽  
Phase Transition Temperature ◽  
Lipid Vesicles ◽  
Freezing Stress ◽  
Amorphous Ice ◽  
Different Temperatures ◽  
Band Pass ◽  
Lipid Polymorphism

TEM imaging of frozen-hydrated lipid vesicles has been done by several groups Thermotrophic and lyotrophic polymorphism has been reported. By using image processing, computer simulation and tilt experiments, we tried to learn about the influence of freezing-stress and defocus artifacts on the lipid polymorphism and fine structure of the bilayer profile. We show integrated membrane proteins do modulate the bilayer structure and the morphology of the vesicles.Phase transitions of DMPC vesicles were visualized after freezing under equilibrium conditions at different temperatures in a controlled-environment vitrification system. Below the main phase transition temperature of 24°C (Fig. 1), vesicles show a facetted appearance due to the quasicrystalline areas. A gradual increase in temperature leads to melting processes with different morphology in the bilayer profile. Far above the phase transition temperature the bilayer profile is still present. In the band-pass-filtered images (Fig. 2) no significant change in the width of the bilayer profile is visible.

scholarly journals Thermal, ferroelastic, and structural properties near phase transitions of organic–inorganic perovskite type [NH3(CH2)3NH3]CdBr4 crystals

RSC Advances ◽  
2021 ◽  
Vol 11 (29) ◽  
pp. 17622-17629
Author(s):  
Ae Ran Lim
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Thermal Behavior ◽  
Structural Properties ◽  
Structural Dynamics ◽  
Transition Temperatures ◽  
Inorganic Perovskite ◽  
Phase Transition Temperatures ◽  
Perovskite Type

We studied the thermal behavior and structural dynamics of [NH3(CH2)3NH3]CdBr4 near phase transition temperatures.

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