CIDCA   05380
CENTRO DE INVESTIGACION Y DESARROLLO EN CRIOTECNOLOGIA DE ALIMENTOS
Unidad Ejecutora - UE
artículos
Título:
How important are internal temperature gradients in french strwas during freezing of bovine sperm in nitrogen vapor?
Autor/es:
M.V. SANTOS; M. SANSINENA; N. ZARITZKY; J. CHIRIFE
Revista:
CRYO-LETTERS
Editorial:
CRYO LETTERS
Referencias:
Año: 2013 vol. 34 p. 158 - 165
ISSN:
0143-2044
Resumen:
The subject of present work was to predict internal temperature gradients developed during freezing of bovine sperm diluted in extender, packaged in 0.5 ml French plastic straws and suspended in static liquid nitrogen vapor at -100ºC. For this purpose, a mathematical heat transfer model previously developed to predict freezing times (phase change was considered) of semen/extender packaged in straw was extended to predict internal temperature gradients during the cooling/freezing process. Results showed maximum temperature differences between the centre and the periphery of semen/extender "liquid" column was 1.5ºC for an external heat transfer coefficient, h = 15 W/(m2 K), and only 0.5ºC for h = 5 W/(m2 K). It is concluded that if a thermocouple wire were inserted in a 0.5 ml plastic straw to monitor the freezing process in nitrogen vapor, its radial position would have little importance since expected internal gradients may be safely neglected. This finding facilitates the interpretation of freezing rates in 0.5 ml plastic straws immersed in nitrogen vapor over liquid nitrogen, a widely used method for cryopreservation of bovine spermatozoa.