Effects of Glycerol on the Thermal Properties of Phosphate Buffered Saline and Porcine Liver at Subzero Temperatures

2007 ◽  
Author(s):  
Jeung H. Choi ◽  
John C. Bischof
Keyword(s):  
Phase Transition ◽  
Thermal Properties ◽  
Property Values ◽  
Insufficient Data ◽  
Porcine Liver ◽  
Water Ice ◽  
Subzero Temperatures ◽  
Temperature Ranges ◽  
Phase Change Phenomena ◽  
Phosphate Buffered Saline

Improvements in the prediction of thermal behavior during cryosurgery and cryopreservation can help improve the outcome of these cryobiological applications. The accuracy of the models depends on numerous factors including the kinetics and energy release during phase change phenomena and knowledge of thermal properties. Furthermore, connecting the thermal properties to crystalline, amorphous, and other phases adds an important mechanistic dimension that can also improve and direct an outcome. However, insufficient data for thermal properties in the subzero domain result in reliance on property estimations based usually upon tabulated water-ice data or weight averaged values from known materials primarily in temperature ranges above −40 °C [1]. This study focused on expanding the thermal properties database for both solutions and tissues. Results for Phosphate Buffered Saline (PBS) and porcine liver with glycerol at subzero temperatures (−150 ∼ 0 °C) are reported. The shifting of thermal property values due to sample crystallization, amorphous phase transition, and melting is discussed.

Structural aspects of thermal properties of AgCuS compound

2020 ◽  
Vol 34 (05) ◽  
pp. 2050066 ◽  
Author(s):  
Y. I. Aliyev ◽  
Y. G. Asadov ◽  
T. M. Ilyasli ◽  
F. M. Mammadov ◽  
T. G. Naghiyev ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Heat Capacity ◽  
Thermal Properties ◽  
Central Peak ◽  
Orthorhombic Symmetry ◽  
Cubic Symmetry ◽  
Space Group ◽  
Temperature Ranges ◽  
Structural Aspects

The crystal structure and thermal properties of AgCuS compound were investigated at high temperature ranges. It was found that the crystal structure of these compounds has orthorhombic symmetry with Cmcm space group at the normal condition and room temperature. The phase transition to cubic symmetry with Fm3m space group is observed at [Formula: see text] temperature. The endoeffect was observed with a central peak at [Formula: see text] in the differential thermal analysis. The temperature dependence on heat capacity was obtained in the range of [Formula: see text] temperature. Thermodynamic parameters have been determined: enthalpy and heat capacity. The value of enthalpy was calculated according to the temperature of the phase transition.

Effects of a Cryoprotective Agent on Thermal Properties of Solutions at Subzero Temperatures

2004 ◽  
Author(s):  
Jeung Wan Choi ◽  
Bumsoo Han ◽  
John C. Bischof
Keyword(s):  
Thermal Properties ◽  
Specific Heat ◽  
Transfer Model ◽  
Glycerol Concentration ◽  
Specific Heat Data ◽  
Cryoprotective Agent ◽  
Subzero Temperatures ◽  
Measurement Results ◽  
Phosphate Buffered Saline ◽  
Heat Data

The study focuses on evaluating the effects of adding a cryoprotective agent (CPA) on the thermal properties of solutions. Preliminary results for Phosphate Buffered Saline (PBS) with glycerol at subzero temperatures are reported. A Differential Scanning Calorimeter (DSC) was used to measure the specific heat and to observe latent heat release. Cryomicroscopy was performed using a cryostage to control the cooling and heating rate of the sample and visually observe microscopic changes. The specific heat data obtained from the DSC is also used for predicting bulk thermal conductivity by a transient heat transfer model using a thermistor. Thermal properties measurement results show opposing trends prior to and after devitrification and melting events with respect to glycerol concentration.

scholarly journals The Variation Mechanism of Thermal Properties of Loess with Different Water Contents during Freezing

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Xihao Dong ◽  
Shuai Liu ◽  
Yuanxiang Yu
Keyword(s):  
Heat Transfer ◽  
Phase Transition ◽  
Thermal Conductivity ◽  
Heat Capacity ◽  
Thermal Properties ◽  
Water Content ◽  
Volumetric Heat Capacity ◽  
Soil Particles ◽  
Water Ice ◽  
Variation Mechanism

The thermal properties of soils are affected by many factors, such as temperature, water content, and structure. Based on the transient plane source method of thermal physics, the thermal properties of loess with different water content during the freezing process were tested. We analyzed the variation mechanism of thermal properties from the perspective of phase change. Based on the Pore/Particle and Crack Analysis System (PCAS) and theory of heat transfer, we then analyzed the microstructure and heat conduction process of loess. And a calculation model of volumetric heat capacity of frozen soil was presented. The results show that, in the major phase transition zone, the variation of the thermal properties of loess with temperature is the most significant. And the thermal diffusivity increases sharply with the significant increase of thermal conductivity and the rapid decrease of volumetric heat capacity. Moisture content not only increases the thermal conductivity and volume heat capacity of loess but also makes the influence of temperature on the thermophysical parameters more significant. The effect of temperature on thermal properties is mainly due to the change of heat transfer media caused by phase transition of water-ice, followed by the change of thermal properties of heat transfer media such as soil particles, water, ice, and air with temperature. Increasing the water content reduces the contact thermal resistance between soil particles because of the increase in the thickness of the water film on the surface of soil particles and the thermal conductivity of the heat transfer medium between particles, thus changing the thermal properties of soils.

Effect of Palmitoyl Nanogold Particles on the Subzero Thermal Properties of Phosphate Buffered Saline Solutions

2010 ◽  
Vol 1 (2) ◽  
Author(s):  
A. Guha ◽  
R. V. Devireddy
Keyword(s):  
Thermal Properties ◽  
Melting Temperature ◽  
Homogeneous Nucleation ◽  
Nucleation Temperature ◽  
Subzero Temperatures ◽  
Dmso Concentration ◽  
Change Temperature ◽  
Nanogold Particles ◽  
Saline Solutions ◽  
Phosphate Buffered Saline

Extensive studies document the effect of nanoparticles on thermal properties of fluids, such as thermal conductivity, although very few exist at subzero temperatures. The current study reports the effect of 1.4 nm palmitoyl nanogold particles (NPs) on the freezing properties of phosphate buffered saline solutions with the help of a differential scanning calorimeter. The results show that NPs have a complex effect on the two properties of interest, i.e., homogeneous nucleation temperature (Th) and phase change temperature (or the melting temperature, Tm). The homogeneous nucleation temperature was significantly elevated at a concentration of 1 nM/ml NPs with 0.167% (v/v) DMSO, and 3 nM/ml NPs with 0.50% (v/v) DMSO concentration, whereas at the other concentrations (1.2 nM/ml NPs with 0.20% DMSO, 1.5 nM/ml NPs with 0.25% DSMO, and 6 nM/ml NPs with 1% DMSO), it was significantly depressed. A similar phenomenon was also noticed in the measured values of the melting temperature of PBS solutions.

Survival of mouse blastocysts after low-temperature preservation under high pressure

2004 ◽  
Vol 52 (4) ◽  
pp. 479-487 ◽  
Author(s):  
Cs. Pribenszky ◽  
M. Molnár ◽  
S. Cseh ◽  
L. Solti
Keyword(s):  
Phase Transition ◽  
Hydrostatic Pressure ◽  
Low Temperature ◽  
High Hydrostatic Pressure ◽  
Room Temperature ◽  
Freezing Point ◽  
Significant Loss ◽  
Embryo Cryopreservation ◽  
Subzero Temperatures ◽  
Survival Capacity

Cryoinjuries are almost inevitable during the freezing of embryos. The present study examines the possibility of using high hydrostatic pressure to reduce substantially the freezing point of the embryo-holding solution, in order to preserve embryos at subzero temperatures, thus avoiding all the disadvantages of freezing. The pressure of 210 MPa lowers the phase transition temperature of water to -21°C. According to the results of this study, embryos can survive in high hydrostatic pressure environment at room temperature; the time embryos spend under pressure without significant loss in their survival could be lengthened by gradual decompression. Pressurisation at 0°C significantly reduced the survival capacity of the embryos; gradual decompression had no beneficial effect on survival at that stage. Based on the findings, the use of the phenomena is not applicable in this form, since pressure and low temperature together proved to be lethal to the embryos in these experiments. The application of hydrostatic pressure in embryo cryopreservation requires more detailed research, although the experience gained in this study can be applied usefully in different circumstances.

scholarly journals DC and AC Conductivity, Biosolubility and Thermal Properties of Mg-Doped Na2O–CaO–P2O5 Glasses

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2626
Author(s):  
Natalia Anna Wójcik ◽  
Sharafat Ali ◽  
Jakub Lech Karczewski ◽  
Bo Jonson ◽  
Michał Bartmański ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Saline Solution ◽  
Glass Structure ◽  
Glass Network ◽  
Bioactive Glasses ◽  
Dc And Ac Conductivity ◽  
Impedance Spectroscopy Technique ◽  
Mg Content ◽  
Phosphate Buffered Saline ◽  
Mg Doped

Bioactive glasses have recently been extensively used to replace, regenerate, and repair hard tissues in the human body because of their ability to bond with living tissue. In this work, the effects of replacing Na2O with MgO on the electrical, biosolubility, and thermal properties of the target glass 10Na2O–60P2O5–30CaO (in mol%) were investigated. The electrical properties of the glasses were studied with the impedance spectroscopy technique. At 473 K, DC conductivity values decreased from 4.21 × 10−11 to 4.21 × 10−12 S cm−1 after complete substitution of MgO for Na2O. All samples had a similar activation energy of the DC conduction process ~1.27 eV. Conduction mechanisms were found to be due to hop of ions: Na+, Mg2+, and probable H+. FTIR analysis showed that, as the Mg content increased, the Q2 unit (PO2−) shifted towards higher wavenumbers. The proportion of Q3 unit (P2O5) decreased in the glass structure. This confirmed that the replacement of Na+ by Mg2+ was accompanied by concurrent polymerization of the calcium–phosphate glass network. The biosolubility test in the phosphate-buffered saline solution showed that the magnesium addition enhanced the biosolubility properties of Na2O–CaO–P2O5 glasses by increasing their dissolution rate and supporting forming CaP-rich layers on the surface. The glass transition temperature increased, and thermal stability decreased substantially upon substitution of Na2O by MgO.

scholarly journals Variation of thermal conductivity of DPPC lipid bilayer membranes around the phase transition temperature

2017 ◽  
Vol 14 (130) ◽  
pp. 20170127 ◽  
Author(s):  
Sina Youssefian ◽  
Nima Rahbar ◽  
Christopher R. Lambert ◽  
Steven Van Dessel
Keyword(s):  
Phase Transition ◽  
Thermal Conductivity ◽  
Thermal Properties ◽  
Transition Temperature ◽  
Lipid Bilayer ◽  
Lipid Bilayers ◽  
Phase Transition Temperature ◽  
Temperature Gradients ◽  
Phase Behaviour ◽  
Gel Phase

Given their amphiphilic nature and chemical structure, phospholipids exhibit a strong thermotropic and lyotropic phase behaviour in an aqueous environment. Around the phase transition temperature, phospholipids transform from a gel-like state to a fluid crystalline structure. In this transition, many key characteristics of the lipid bilayers such as structure and thermal properties alter. In this study, we employed atomistic simulation techniques to study the structure and underlying mechanisms of heat transfer in dipalmitoylphosphatidylcholine (DPPC) lipid bilayers around the fluid–gel phase transformation. To investigate this phenomenon, we performed non-equilibrium molecular dynamics simulations for a range of different temperature gradients. The results show that the thermal properties of the DPPC bilayer are highly dependent on the temperature gradient. Higher temperature gradients cause an increase in the thermal conductivity of the DPPC lipid bilayer. We also found that the thermal conductivity of DPPC is lowest at the transition temperature whereby one lipid leaflet is in the gel phase and the other is in the liquid crystalline phase. This is essentially related to a growth in thermal resistance between the two leaflets of lipid at the transition temperature. These results provide significant new insights into developing new thermal insulation for engineering applications.

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