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Freezing point
About: Freezing point is a research topic. Over the lifetime, 10563 publications have been published within this topic receiving 175858 citations.
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TL;DR: In this article, the authors used mouse embryos to examine the feasibility of obtaining high survival following vitrification of both the intra and extracellular solutions and report that in properly controlled conditions embryos seem to survive in high proportions after cryopreservation in the absence of ice.
Abstract: The failure of complex mammalian organs, such as the kidney, to function following freezing to low temperatures is thought to be due largely to mechanical disruption of the intercellular architecture by the formation of extracellular ice. Classical approaches to the avoidance of ice formation through the imposition of ultra-rapid cooling and warming rates or by gradual depression of the equilibrium freezing point during cooling to -80 degrees C have not been adequate. An alternative approach relies on the ability of highly concentrated aqueous solutions of cryoprotective agents to supercool to very low temperatures. At sufficiently low temperatures, these solutions become so viscous that they solidify without the formation of ice, a process termed vitrification. When embryo suspensions are cryopreserved using conventional procedures, this supercooling behaviour allows intracellular vitrification, even in the presence of extracellular ice. We have therefore used mouse embryos to examine the feasibility of obtaining high survival following vitrification of both the intra- and extracellular solutions and report here that in properly controlled conditions embryos seem to survive in high proportions after cryopreservation in the absence of ice.
1,545 citations
TL;DR: In this article, the viscosity of the liquid normal paraffins can be accurately defined as a simple function of relative free space except for values in the neighborhood of the freezing points of each compound.
Abstract: In this paper it is shown that the viscosity of the liquid normal paraffins can be accurately defined as a simple function of relative free‐space except for values in the neighborhood of the freezing points of each compound A novel method of extrapolating the specific volumes of this family of compounds to absolute zero is described which permits the calculation of reliable values of the relative free‐space from density dataAn expression of the same form as the author's function, but in which temperature rather than free‐space is the primary variable (the so‐called Andrade equation), fails to reproduce the viscosity of n‐heptadecane over the same range of temperatures within the limits of the known accuracy of the measurements
1,495 citations
University of Alaska Fairbanks1, Marine Biological Laboratory2, University of Colorado Boulder3, Middlebury College4, United States Geological Survey5, Michigan State University6, San Diego State University7, Colorado State University8, Monash University9, University of Delaware10, Cold Regions Research and Engineering Laboratory11, National Oceanic and Atmospheric Administration12, California State University San Marcos13, United States Forest Service14, University of Alaska Anchorage15
TL;DR: In this article, the authors present a broad array of evidence that illustrates con- vincingly; the Arctic is undergoing a system-wide response to an altered climatic state.
Abstract: The Arctic climate is changing. Permafrost is warming, hydrological processes are chang- ing and biological and social systems are also evolving in response to these changing conditions. Knowing how the structure and function of arctic terrestrial ecosystems are responding to recent and persistent climate change is paramount to understanding the future state of the Earth system and how humans will need to adapt. Our holistic review presents a broad array of evidence that illustrates con- vincingly; the Arctic is undergoing a system-wide response to an altered climatic state. New extreme and seasonal surface climatic conditions are being experienced, a range of biophysical states and pro- cesses influenced by the threshold and phase change of freezing point are being altered, hydrological and biogeochemical cycles are shifting, and more regularly human sub-systems are being affected. Importantly, the patterns, magnitude and mechanisms of change have sometimes been unpredictable or difficult to isolate due to compounding factors. In almost every discipline represented, we show
1,315 citations
TL;DR: In this paper, the vapour pressure of ice and supercooled water is reviewed with an emphasis on atmospheric applications, and various parametrizations are given for the vapor pressure, molar heat capacity, and latent heat of both ice and liquid water.
Abstract: The vapour pressures of ice and supercooled water are reviewed with an emphasis on atmospheric applications. Parametrizations are given for the vapour pressure, molar heat capacity, and latent heat of vaporization of both ice and liquid water. For ice, the experimental vapour pressure data are in agreement with a derivation from the Clapeyron equation. Below 200 K cubic ice may affect the vapour pressure of ice both in the atmosphere and in the laboratory. All of the commonly used parametrizations for the vapour pressure of supercooled water are extrapolations that were not originally intended for use below the freezing point. In addition, the World Meteorological Organization definition of the vapour pressure of supercooled water contains an easily overlooked typographical error. Recent data on the molar heat capacity of supercooled water are used to derive its vapour pressure. Nevertheless, the uncertainty is such that measurements of the deliquescence and freezing behaviour of aerosol particles are beginning to be limited by uncertainties in the thermodynamics of supercooled water. Copyright © 2005 Royal Meteorological Society
1,171 citations
TL;DR: The hypothesis is advanced that cryopreserved mammalian spermatozoa are in a state resembling capacitation, which accounts for their relatively reduced longevity and their readiness to undergo egg penetration without incubation.
Abstract: New research on the cooling and cryopreservation of mammalian spermatozoa is reviewed in the context of the older literature. Cryoinjury to a variety of cell organelles is regarded as being due to the two major stresses of cryopreservation, i.e., the change in temperature, and the formation and dissolution of ice and its consequences. Since the cryopreservation process involves departure of the cells from and return to body temperature, both cold shock and warm shock are included as potential stresses to be considered, as well as the stages involving cooling below the freezing point of the medium. The causes of cryoinjury are reconsidered and new concepts concerning the influence of osmotic stress are presented. Heterogeneity of the sperm population is discussed in the context of the success with which spermatozoa can be cryopreserved between and within ejaculates and individuals. The functional state of frozen and thawed spermatozoa is examined on the basis of published results of structural and functional tests of sperm competence. The hypothesis is advanced that cryopreserved mammalian spermatozoa are in a state resembling capacitation, which accounts for their relatively reduced longevity and their readiness to undergo egg penetration without incubation. The importance of this to the utilization of cryopreserved spermatozoa is examined, and proposals are made for new avenues of research to overcome these problems.
1,091 citations