Effect of precooling conditions on the ice nucleation temperature and freezing characteristics of semisolid matrices

2021 ◽  
Vol 291 ◽  
pp. 110232
Author(s):  
Young Chan Yun ◽  
Karna Ramachandraiah ◽  
Geun-Pyo Hong
Keyword(s):  
Ice Nucleation ◽  
Nucleation Temperature

scholarly journals Characterization of aerosol particles at Cabo Verde close to sea level and at the cloud level – Part 2: Ice-nucleating particles in air, cloud and seawater

2020 ◽  
Vol 20 (3) ◽  
pp. 1451-1468 ◽  
Author(s):  
Xianda Gong ◽  
Heike Wex ◽  
Manuela van Pinxteren ◽  
Nadja Triesch ◽  
Khanneh Wadinga Fomba ◽  
...  
Keyword(s):  
Sea Level ◽  
Cloud Water ◽  
Ice Nucleation ◽  
Cape Verde ◽  
Nucleation Temperature ◽  
Sea Spray ◽  
Cloud Droplets ◽  
Cabo Verde ◽  
Active Particles ◽  
Sea Surface Microlayer

Abstract. Ice-nucleating particles (INPs) in the troposphere can form ice in clouds via heterogeneous ice nucleation. Yet, atmospheric number concentrations of INPs (NINP) are not well characterized, and, although there is some understanding of their sources, it is still unclear to what extend different sources contribute or if all sources are known. In this work, we examined properties of INPs at Cabo Verde (a.k.a. Cape Verde) from different environmental compartments: the oceanic sea surface microlayer (SML), underlying water (ULW), cloud water and the atmosphere close to both sea level and cloud level. Both enrichment and depletion of NINP in SML compared to ULW were observed. The enrichment factor (EF) varied from roughly 0.4 to 11, and there was no clear trend in EF with ice-nucleation temperature. NINP values in PM10 sampled at Cape Verde Atmospheric Observatory (CVAO) at any particular ice-nucleation temperature spanned around 1 order of magnitude below −15 ∘C, and about 2 orders of magnitude at warmer temperatures (>-12 ∘C). Among the 17 PM10 samples at CVAO, three PM10 filters showed elevated NINP at warm temperatures, e.g., above 0.01 L−1 at −10 ∘C. After heating samples at 95 ∘C for 1 h, the elevated NINP at the warm temperatures disappeared, indicating that these highly ice active INPs were most likely biological particles. INP number concentrations in PM1 were generally lower than those in PM10 at CVAO. About 83±22 %, 67±18 % and 77±14 % (median±standard deviation) of INPs had a diameter >1 µm at ice-nucleation temperatures of −12, −15 and −18 ∘C, respectively. PM1 at CVAO did not show such elevated NINP at warm temperatures. Consequently, the difference in NINP between PM1 and PM10 at CVAO suggests that biological ice-active particles were present in the supermicron size range. NINP in PM10 at CVAO was found to be similar to that on Monte Verde (MV, at 744 m a.s.l.) during noncloud events. During cloud events, most INPs on MV were activated to cloud droplets. When highly ice active particles were present in PM10 filters at CVAO, they were not observed in PM10 filters on MV but in cloud water samples instead. This is direct evidence that these INPs, which are likely biological, are activated to cloud droplets during cloud events. For the observed air masses, atmospheric NINP values in air fit well to the concentrations observed in cloud water. When comparing concentrations of both sea salt and INPs in both seawater and PM10 filters, it can be concluded that sea spray aerosol (SSA) only contributed a minor fraction to the atmospheric NINP. This latter conclusion still holds when accounting for an enrichment of organic carbon in supermicron particles during sea spray generation as reported in literature.

scholarly journals Two-Step Freezing Procedure for Cryopreservation of Rumen Ciliates, an Effective Tool for Creation of a Frozen Rumen Protozoa Bank

2003 ◽  
Vol 69 (7) ◽  
pp. 3826-3832 ◽  
Author(s):  
E. Nsabimana ◽  
S. Kišidayová ◽  
D. Macheboeuf ◽  
C. J. Newbold ◽  
J. P. Jouany
Keyword(s):  
Liquid Nitrogen ◽  
Ice Nucleation ◽  
Slow Freezing ◽  
Nucleation Temperature ◽  
Subzero Temperature ◽  
Equilibration Time ◽  
Rumen Protozoa ◽  
Ciliate Species ◽  
Freezing Procedure ◽  
Holding Temperature

ABSTRACT The present study aimed at the long-term storage of rumen protozoa as living cells in liquid nitrogen. The two-step or interrupted slow freezing procedure was used to cryopreserve six of the dominant species of rumen ciliates isolated from monofaunated animals, Dasytricha ruminantium, Entodinium caudatum, Epidinium ecaudatum caudatum, Eudiplodinium maggii, Isotricha prostoma, and Polyplastron multivesiculatum. We optimized the first step in the interrupted slow freezing procedure, from the extracellular ice nucleation temperature to the holding temperature, and studied the effects of the cooling rates on survival. In addition to the nature of the cryoprotectant (dimethyl sulfoxide), the equilibration temperature and equilibration time (25°C and 5 min, respectively), and the holding time at subzero temperature (45 min) recommended previously (S. Kišidayová, J. Microbiol. Methods 22:185-192, 1995), we found that a holding temperature of −30°C, a cooling rate from extracellular ice nucleation temperature to holding temperature of between 1.2°C/min and 2.5°C/min, depending on the ciliate, and rumen juice as the freezing and thawing medium markedly improved the survival rate. Survival rates determined after 2 weeks in liquid nitrogen were 100% for Isotricha, 98% for Dasytricha, 85% for Epidinium, 79% for Polyplastron, 63% for Eudiplodinium, and 60% for Entodinium. They were not significantly modified after a period of 1 year in liquid nitrogen. Four of the five ciliate species cryopreserved for 8 months in liquid nitrogen successfully colonized the rumen when inoculated into defaunated animals. These results have made it possible to set up a bank of cryopreserved rumen protozoa.

scholarly journals Ice Nucleation, Freezing Injury, and Colonization of `Totem' Strawberry Flowers with Ice-nucleation-active (INA) Bacteria

1998 ◽  
Vol 123 (2) ◽  
pp. 234-238 ◽  
Author(s):  
Michele R. Warmund ◽  
James T. English
Keyword(s):  
Pseudomonas Syringae ◽  
Ice Nucleation ◽  
Deionized Water ◽  
Freezing Injury ◽  
Nucleation Temperature ◽  
Ice Formation ◽  
Fragaria Ananassa ◽  
Naturally Occurring ◽  
Ina Bacteria ◽  
Wetness Period

INA bacteria were isolated from primary flowers of `Totem' strawberry (Fragaria ×ananassa Duch.) plants that had been previously inoculated with strain Cit 7 of Pseudomonas syringae van Hall or noninoculated to determine their relationship to ice-nucleation temperature and floral injury. Mean ice-nucleation temperature of inoculated and noninoculated flowers was -2.2 and -2.8 °C, respectively. Primary flowers of noninoculated plants survived lower temperatures than those of inoculated plants. In another experiment, noninoculated plants were misted with sterile deionized water and incubated for 0, 12, 24, 36, or 48 hours at 25 °C day/10 °C night, and naturally occurring INA bacteria were isolated from primary flowers. INA bacterial densities increased exponentially with increasing incubation period. The critical wetness period for INA bacteria to establish a sufficient density to increase the likelihood of floral injury at -2.5 °C was 24 hours. Longer wetness periods resulted in higher INA bacterial densities but did not increase the floral mortality rate. Thermal analysis demonstrated that the ice nucleation temperature was associated with strawberry floral injury. Thus, low temperature survival of flowers was adversely affected by moisture for ≥24 h due to the presence of a sufficient density of INA bacteria to incite ice formation and floral injury.

Ultrafast X-ray probing of water structure below the homogeneous ice nucleation temperature

Nature ◽  
2014 ◽  
Vol 510 (7505) ◽  
pp. 381-384 ◽  
Author(s):  
J. A. Sellberg ◽  
C. Huang ◽  
T. A. McQueen ◽  
N. D. Loh ◽  
H. Laksmono ◽  
...  
Keyword(s):  
Water Structure ◽  
Ice Nucleation ◽  
Nucleation Temperature ◽  
X Ray

scholarly journals Effect of the expression of aquaporins 1 and 3 in mouse oocytes and compacted eight-cell embryos on the nucleation temperature for intracellular ice formation

Reproduction ◽  
2011 ◽  
Vol 142 (4) ◽  
pp. 505-515 ◽  
Author(s):  
Shinsuke Seki ◽  
Keisuke Edashige ◽  
Sakiko Wada ◽  
Peter Mazur
Keyword(s):  
Plasma Membrane ◽  
Plasma Membranes ◽  
Cell Types ◽  
Ice Nucleation ◽  
Nucleation Temperature ◽  
Ice Formation ◽  
Mouse Oocytes ◽  
Intracellular Ice Formation ◽  
Intracellular Ice ◽  
Mature Mouse

The occurrence of intracellular ice formation (IIF) is the most important factor determining whether cells survive a cryopreservation procedure. What is not clear is the mechanism or route by which an external ice crystal can traverse the plasma membrane and cause the heterogeneous nucleation of the supercooled solution within the cell. We have hypothesized that one route is through preexisting pores in aquaporin (AQP) proteins that span the plasma membranes of many cell types. Since the plasma membrane of mature mouse oocytes expresses little AQP, we compared the ice nucleation temperature of native oocytes with that of oocytes induced to express AQP1 and AQP3. The oocytes were suspended in 1.0 M ethylene glycol in PBS for 15 min, cooled in a Linkam cryostage to −7.0 °C, induced to freeze externally, and finally cooled at 20 °C/min to −70 °C. IIF that occurred during the 20 °C/min cooling is manifested by abrupt black flashing. The mean IIF temperatures for native oocytes, for oocytes sham injected with water, for oocytes expressing AQP1, and for those expressing AQP3 were −34, −40, −35, and −25 °C respectively. The fact that the ice nucleation temperature of oocytes expressing AQP3 was 10–15 °C higher than the others is consistent with our hypothesis. AQP3 pores can supposedly be closed by low pH or by treatment with double-strandedAqp3RNA. However, when morulae were subjected to such treatments, the IIF temperature still remained high. A possible explanation is suggested.

Relation between freezing temperature and length of conifer needles

1968 ◽  
Vol 46 (10) ◽  
pp. 1211-1213 ◽  
Author(s):  
Shosuke Kaku ◽  
R.W. Salt
Keyword(s):  
Water Content ◽  
Cell Walls ◽  
Freezing Temperature ◽  
Ice Nucleation ◽  
Nucleation Temperature ◽  
Nucleation Sites ◽  
Conifer Needles ◽  
Increasing Function

The relationships between freezing temperature (or supercooling) and length, weight, and water content of Pinus and Cedrus needles were investigated. Freezing temperature was an increasing function of each of these three variables. When Pinus needles were cut proximally to uniform length (50 mm), supercooling was unaffected by either weight or water content. Thus, ice nucleation temperature was an increasing function of the length of needles, or, more precisely, of the length of the stele, or, still more precisely, of the number of water-conducting capillary units contributing to that length, but ultimately of the number and quality of favorable nucleation sites contained therein. It is suggested that nucleation takes place at sites associated with the cell walls and not on nucleators suspended in the water.

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