116 IMPROVED SURVIVAL BY CRYOPRESERVING RHESUS MACAQUE (MACACA MULATTA) SPERMATOZOA WITH DIRECTIONAL FREEZING TECHNIQUE

2010 ◽  
Vol 22 (1) ◽  
pp. 217 ◽  
Author(s):  
W. Si ◽  
Y. Lu ◽  
X. He ◽  
S. Ji ◽  
Y. Niu ◽  
...  
Keyword(s):  
Rhesus Monkey ◽  
Cooling Rate ◽  
Sperm Motility ◽  
Genetically Engineered ◽  
Human Diseases ◽  
Slow Cooling ◽  
Cooling Rates ◽  
Important Species ◽  
Directional Freezing ◽  
Acrosomal Integrity

A significant increase in nonhuman primate models of human diseases will be expected in the near future since the successes in production of genetically engineered rhesus monkey models of human diseases. Sperm banking can provide an effective way to preserve valuable genetic resources. Our objective was to (1) develop a protocol using directional freezing technique (DFT) for rhesus monkey spermatozoa cryopreservation, which allows precise control of the velocity and the morphology of the ice-front propagation by transferring the tubes loaded with 2 mL sperm samples at a controllable velocity through two separate chambers with controllable temperature settings, and (2) achieve survival rate that was higher than that achieved with conventional freezing technique (CFT), by which sperm samples were cryopreserved in 0.25 mL straws with liquid nitrogen vapor in a styrofoam box. Sperm motility, acrosomal integrity, and in vitro fertilization (IVF) assay were used to assess the function of frozen-thawed spermatozoa. Data were analyzed by ANOVA and Fisher protected LSD test. Experiment 1 was aimed at optimizing the cooling rate using DFT. Tubes were frozen using the multi-thermal gradient freezing device (MTG 516, Harmony CryoCareTM, IMT Ltd.) at fast (16°C/min), medium (12°C/min), and slow (7°C/min) cooling rates, which corresponded to the transferring velocities (2.5, 1.5, and 0.5 mm s-1, respectively). The results showed that spermatozoa frozen at fast and medium cooling rates showed significantly higher frozen-thawed motility than those frozen at slow cooling rate (61% and 59% v. 50%, P < 0.05). However, no difference was observed on sperm acrosomal integrity among the experimental groups (84, 80, and 78%, respectively, P > 0.05). The purposes of Experiment 2 were determined to examine if using DFT at the optimized cooling rate (12°C/min) can improve the cryo-survival of rhesus monkey spermatozoa compared with CFT. Our results showed that spermatozoa cryopreserved by using DFT achieved significantly higher frozen-thawed sperm motility that those cryopreserved by using CFT (64 v. 54%, P < 0.05). However, no difference was observed on acrosomal integrity between spermatozoa cryopreserved by DFT and CFT (84 and 83%, respectively; P > 0.05). The function of spermatozoa cryopreserved by using DFT was further evaluated by IVF. Females were treated with rhFSH twice-daily for 8 days after the onset of menses and following a treatment of hCG injection on Day 9. Cumulus-oocyte complexes were collected by laparoscopic follicular aspiration 32 h later. Of the inseminated oocytes, 79% were fertilized and 90 and 53% of the resulting zygotes developed into 2-cell and blastocysts, respectively. The fertilization rate was lower and the blastocyst rate was slightly higher than our previous report when fresh spermatozoa were used for IVF (94 and 52%, respectively). Our results indicate that spermatozoa of rhesus monkeys can be effectively cryopreserved using DFT in large volume. This finding provided a new and effective way for genetics preservation purposes in this important species.

Assessment of basic seminal characteristics, sperm cryopreservation and heterologous in vitro fertilisation in the fishing cat (Prionailurus viverrinus)

2006 ◽  
Vol 18 (3) ◽  
pp. 373 ◽  
Author(s):  
Khongsak Thiangtum ◽  
William F. Swanson ◽  
JoGayle Howard ◽  
Wanchai Tunwattana ◽  
Dakara Tongthainan ◽  
...  
Keyword(s):  
Sperm Motility ◽  
Sperm Morphology ◽  
Domestic Cat ◽  
Ex Situ ◽  
In Vitro Fertilisation ◽  
Genetic Management ◽  
Slow Cooling ◽  
Breeding Programmes ◽  
Acrosomal Integrity

Conservation of the fishing cat, a threatened south-east Asian felid, could benefit from effective ex situ genetic management and breeding programmes, including the use of assisted reproduction. The aims of the present study were to: (1) characterise basal seminal traits of fishing cats in Thailand zoos; and (2) investigate the effect of cryopreservation on sperm motility, acrosomal integrity and in vitro function. Seminal traits were evaluated in electroejaculates collected from eight males. Spermatozoa were diluted in n-tris(hydroxymethyl)-methyl-2-aminoethanesulfonic acid Tris (TEST)-yolk buffer (TYB) without glycerol, then diluted further with TYB with glycerol (4% final concentration) at either 25°C or after slow cooling to 5°C and frozen in straws over liquid nitrogen vapour. After thawing, sperm function was assessed by insemination of viable domestic cat oocytes. Fishing cat ejaculates averaged (± s.e.m.) 43.6 ± 14.2 × 106 motile spermatozoa with 33.5 ± 6.8% normal sperm morphology. Semen processing had a negligible effect (P > 0.05) on sperm motility and acrosomal integrity, but values were reduced (P < 0.05) after thawing. All thawed samples fertilised domestic cat oocytes, with 62.1% (36/58) of mature oocytes cleaving. Glycerol addition at 5°C resulted in higher (P < 0.05) post-thaw motility and intact acrosomes than glycerol addition at 25°C. In conclusion, good-quality ejaculates can be obtained from Thai fishing cats and their spermatozoa exhibit adequate function after cryopreservation for in vitro fertilisation procedures.

Slow cooling prevents cold-induced damage to sperm motility and acrosomal integrity in the black-footed ferret (Mustela nigripes)

2007 ◽  
Vol 19 (5) ◽  
pp. 652 ◽  
Author(s):  
R. M. Santymire ◽  
P. E. Marinari ◽  
J. S. Kreeger ◽  
D. E. Wildt ◽  
J. G. Howard
Keyword(s):  
Sperm Motility ◽  
Seminal Plasma ◽  
Artificial Insemination ◽  
Sperm Cryopreservation ◽  
Slow Cooling ◽  
Rapid Cooling ◽  
Mustela Nigripes ◽  
Factors Influencing ◽  
Rate Of Cooling ◽  
Acrosomal Integrity

The endangered black-footed ferret (Mustela nigripes) has benefited from artificial insemination; however, improved sperm cryopreservation protocols are still needed. The present study focused on identifying factors influencing gamete survival during processing before cryopreservation, including: (1) the presence or absence of seminal plasma; (2) temperature (25°C v. 37°C); (3) type of medium (Ham’s F10 medium v. TEST yolk buffer [TYB]); (4) cooling rate (slow, rapid and ultra-rapid); and (5) the presence or absence of glycerol. Seminal plasma did not compromise (P > 0.05) sperm motility or acrosomal integrity. Sperm motility traits were maintained longer (P < 0.05) at 25°C than at 37°C in Ham’s or TYB, but temperature did not affect (P > 0.05) acrosomal integrity. Overall, TYB maintained optimal (P < 0.05) sperm motility compared with Ham’s medium, but Ham’s medium maintained more (P < 0.05) intact acrosomes than TYB. Slow cooling (0.2°C min–1) was optimal (P < 0.05) compared to rapid cooling (1°C min–1), and ultra-rapid cooling (9°C min–1) was found to be highly detrimental (P < 0.05). Results obtained in TYB with 0% or 4% glycerol were comparable (P > 0.05), indicating that 4% glycerol was non-toxic to ferret sperm; however, glycerol failed to ameliorate the detrimental effects of either rapid or ultra-rapid cooling. The results of the present study demonstrate that the damage observed to black-footed ferret spermatozoa is derived largely from the rate of cooling.

scholarly journals Thermal stress, cooling-rate and fictive temperature of silicate melts

2021 ◽  
Vol 176 (10) ◽  
Author(s):  
Sharon L. Webb
Keyword(s):  
Heat Capacity ◽  
Cooling Rate ◽  
Heating Rate ◽  
Calibration Curve ◽  
Silicate Melts ◽  
Internal Stresses ◽  
Heating Rates ◽  
Fictive Temperature ◽  
Slow Cooling ◽  
Cooling Rates

AbstractThe unknown cooling-rate history of natural silicate melts can be investigated using differential scanning heat capacity measurements together with the limiting fictive temperature analysis calculation. There are a range of processes occurring during cooling and re-heating of natural samples which influence the calculation of the limiting fictive temperature and, therefore, the calculated cooling-rate of the sample. These processes occur at the extremes of slow cooling and fast quenching. The annealing of a sample at a temperature below the glass transition temperature upon cooling results in the subsequent determination of cooling-rates which are up to orders of magnitude too low. In contrast, the internal stresses associated with the faster cooling of obsidian in air result in an added exothermic signal in the heat capacity trace which results in an overestimation of cooling-rate. To calculate cooling-rate of glass using the fictive temperature method, it is necessary to create a calibration curve determined using known cooling- and heating-rates. The calculated unknown cooling-rate of the sample is affected by the magnitude of mismatch between the original cooling-rate and the laboratory heating-rate when using the matched cooling-/heating-rate method to derive a fictive temperature/cooling-rate calibration curve. Cooling-rates slower than the laboratory heating-rate will be overestimated, while cooling-rates faster than the laboratory heating-rate are underestimated. Each of these sources of error in the calculation of cooling-rate of glass materials—annealing, stress release and matched cooling/heating-rate calibration—can affect the calculated cooling-rate by factor of 10 or more.

Influence of Cooling Rates on Phase Transitions of Bent-Core Liquid Crystal 1,3-Phenylene-bis[4-(hexylcarboyloxyl)benzylideneamine]

2010 ◽  
Vol 428-429 ◽  
pp. 247-250 ◽  
Author(s):  
Yuan Ming Huang ◽  
Qing Lan Ma ◽  
Bao Gai Zhai
Keyword(s):  
Differential Scanning Calorimetry ◽  
Phase Transitions ◽  
Liquid Crystal ◽  
Optical Microscopy ◽  
Cooling Rate ◽  
Scanning Calorimetry ◽  
Slow Cooling ◽  
Cooling Rates ◽  
Polarized Optical Microscopy ◽  
Fast Cooling

The influence of cooling rate on the phase transitions of a three-benzene-ring containing bent-core liquid crystal 1,3-phenylene-bis[4-(hexylcarboyloxyl)benzylideneamine] has been investigated by means of differential scanning calorimetry and polarized optical microscopy. Our results show that the cooling rates in the second cooling run pose significant effects on the phase transitions of the bent-core liquid crystal despite the cooling rates in the first cooling run pose little effects on the phase transitions. In the second cooling run, the banana phases survived only when the cooling rates were in the range of 14~15oC/min whereas both slow cooling rates which were less than 13oC/min and fast cooling rates which were higher than 16oC/min made the banana phases disappeared.

Achieving the Dual Phase Structure in Low Alloyed Steel with Slow Cooling Rate

2008 ◽  
Vol 575-578 ◽  
pp. 1117-1122
Author(s):  
Tarja Jäppinen ◽  
Seppo Kivivuori
Keyword(s):  
Cooling Rate ◽  
Phase Structure ◽  
Steel Wire ◽  
Optical Microscope ◽  
Carbon Steels ◽  
Alloying Elements ◽  
Dual Phase ◽  
Low Carbon ◽  
Slow Cooling ◽  
Cooling Rates

In steel wire processing it is difficult to reach a homogenous structure throughout the cross-section of the wire particularly in greater diameters. One alternative for producing a homogenous structure is to find a cooling path with a wide transformation temperature range. Fully austenite steel wire rolled at high temperatures can be decomposed into ferritic-martensitic dual phase structure using relatively slow cooling rates. Test materials were low alloyed low carbon steels with variations in alloying elements. Gleeble-1500 thermomechanical simulator was utilised to study the effect of cooling rate on decomposition of austenite after deformation. The microstructures were studied with an optical microscope. In certain low alloyed steels slow cooling rates eliminate the bainite transformation and instead martensite is formed. The final microstructure depends mainly on the carbon content but also on the amount of other alloying elements and their effects on the austenite phase.

Validation of a Simple Two-Point Method To Assess Restaurant Compliance with Food Code Cooling Rates

2020 ◽  
Vol 84 (1) ◽  
pp. 6-13
Author(s):  
MATTHEW J. IGO ◽  
NICOLE HEDEEN ◽  
DONALD W. SCHAFFNER
Keyword(s):  
Cooling Rate ◽  
Screening Tool ◽  
Point Method ◽  
Cooling Curves ◽  
Simple Linear Regression ◽  
Point Model ◽  
Slow Cooling ◽  
Cooling Rates ◽  
Novel Method ◽  
Almost All

ABSTRACT Outbreaks from improperly cooled foods continue to occur despite clearly described Food Code cooling guidelines. It is difficult for regulators to enforce these guidelines because they are typically in an establishment for less than the 6 h needed to document proper cooling. Prior research proposed using a novel method to estimate cooling rates based on two time-temperature points, but this method has not yet been validated. Time-temperature profiles of 29 different foods were collected in 25 different restaurants during cooling. Cooling curves were divided into two categories: typical (21 foods) and atypical (eight foods) prior to further analysis. Analysis of the typical cooling curves used simple linear regression to calculate cooling rates. The atypical cooling profiles were studied using Monte Carlo simulations of the cooling rate. Almost all linearized typical cooling curves had high (&gt;0.90) R2 values. Six foods with typical cooling profiles that did not pass Food Code cooling times were correctly identified by the two-point model as having slow cooling rates. Three foods that did not pass Food Code cooling times were identified by the two-point model as having marginal cooling rates. Ten of 12 foods identified by the two-point model as having acceptable cooling rates met Food Code cooling times. Most (six of eight) foods that were considered to have atypical cooling curves failed to meet the Food Code cooling times. The two-point model was also able to determine whether these foods would fail based on Food Code guidelines depending upon the simulation criteria used. Our data show that food depth has a strong influence on cooling rate. Containers with a food depth ≥7.6 cm (3 in.) were more likely to have cooling rates slower than the U.S. Food and Drug Administration Model Food Code cooling rate. This analysis shows that the two-point method can be a useful screening tool to identify potential cooling rate problems during a routine restaurant inspection visit. HIGHLIGHTS

The survival of Escherichia coli from freeze–thaw damage: permeability barrier damage and viability

1975 ◽  
Vol 21 (11) ◽  
pp. 1724-1732 ◽  
Author(s):  
Peter H. Calcott ◽  
Robert A. MacLeod
Keyword(s):  
Escherichia Coli ◽  
Cooling Rate ◽  
Permeability Barrier ◽  
Freezing And Thawing ◽  
Slow Cooling ◽  
Cooling Rates ◽  
Rate Range ◽  
Permeability Damage ◽  
Extent Of Damage ◽  
Glucose 6 Phosphate Dehydrogenase

The effect of cooling rate and subsequent warming rate on survival of lactose-limited Escherichia coli was investigated. As previously reported, in the slow cooling rate range, a peak of survival was noted at 8 °C/min with survival decreasing as the cooling rate was increased or decreased from this value. Minimal survival was noted at 100 °C/min; increasing the cooling rate above 100 °C/min increased survival. At cooling rates greater than 200 °C/min, the survival became dependent on subsequent warming rates.Permeability damage, as measured by release of UV-absorbing material, potassium and β-galactosidase, and increased accessibility of glucose-6-phosphate dehydrogenase to its substrates, was dependent on the cooling rate when cells were frozen in either water or saline. For cooling rates less than about 8 °C/min, there was minimal permeability damage to cells frozen in water. However, at rates greater than this value, damage and viability were related; the lower the viability the more the damage to the permeability barrier. The relationship was strengthened by the observations that protectants which increased survival reduced damage as well and that at ultrarapid cooling rates where survivals were dependent on warming rates, the extent of damage was likewise dependent on the warming rate.Saline frozen cells were damaged by freezing and thawing more than comparable water-frozen cells over the whole cooling rate range. At cooling rates less than 8 °C/min, frozen in water, permeability damage of cells frozen in saline increased as the cooling rate decreased. As the cooling rate was increased from 8 °C/min, the damage increased as viability decreased.The relevance of these findings to the two-factor hypothesis of cell death is discussed.

Effect of Cooling Rate on Glass Formation for Some Oxynitride Glasses

2007 ◽  
Vol 554 ◽  
pp. 25-30 ◽  
Author(s):  
Wynette Redington ◽  
Murt Redington ◽  
Stuart Hampshire
Keyword(s):  
Cooling Rate ◽  
Glass Formation ◽  
Resistance Furnace ◽  
Slow Cooling ◽  
Cooling Rates ◽  
X Ray ◽  
Glass Forming ◽  
Wide Range ◽  
Fast Cooling ◽  
Nd Systems

Rapid cooling rates and quenching have traditionally been associated with glass formation. Hampshire et al. [1] investigated oxynitride glasses cooled in a tungsten resistance furnace at approximately 200oC/min and found that fast cooling rates were only important near the limits of the glass-forming region. In the current work on various M-Si-Al-O-N (M=Y, La, Yb, Nd) systems, it was found that even at a relatively slow cooling rate glass formation was still possible for a wide range of compositions. Different cooling rates were investigated to determine the minimum cooling rate at which a glass will form. Quantitative X-ray analysis of melted compositions indicated the relative amounts of amorphous phase and crystalline phase.

Iron-Silicate Glassy Films by Sol-Gel Conversion Induced by Rapid Thermal Processing

1998 ◽  
Vol 525 ◽  
Author(s):  
René E. Van De Leest ◽  
Fred Roozeboom
Keyword(s):  
Cooling Rate ◽  
Thermal Processing ◽  
Sol Gel ◽  
Rapid Thermal Processing ◽  
Iron Silicate ◽  
Precursor Film ◽  
Vibration Band ◽  
Slow Cooling ◽  
Cooling Rates ◽  
Oh Groups

ABSTRACTThe sol-gel system iron triethoxide - tetraethylorthosilicate (TEOS) with the Fe/Si atomic ratio ranging from 0 to 1 has been investigated. Our study leads to the conclusion that the annealing method of the hydrolyzed precursor film determines the type of solid film formed. Annealing by Rapid Thermal Processing (RTP) with its high heating and cooling rates yields amorphous, glassy iron silicate films. These films result from polycondensation reactions between Si-OH and Fe-OH groups of the hydrolyzed precursors forming Fe-O-Si and Si-O-Si bonds. These bonds show a characteristic vibration band in FTIR spectra, which is most intense for Fe/Si = 1, and shifts for increasing Fe/Si ratio from 1073 down to 965 cm-1.The iron silicate film with Fe/Si =1 obtained by RTP displays an optical absorption band around 320 nm, which indicates that Fe3+-ions have a tetrahedral coordination similar to the Si4+-ions in Si02 and glass with tetrahedrally coordinated silicon and iron ions linked by bridging oxygen atoms. The films, typically 0.1 μm thick, annealed by RTP have a smooth, mechanically hard surface. This glassy structure can be formally presented as FeSiOx. Conventional furnace heating with low heating/cooling rates yields nanocrystalline films with predominantly Si-O-Si bonding in grains with sizes below 40 nm. More structural and chemical investigation is needed to elucidate the details of the structure and the formation mechanism of the amorphous compound, but we can conclude that the cooling rate has a direct effect on the degree of non-crystallinity of the compound. The high cooling rate of RTP will retain the Fe-O-Si bonds formed in a state of inequilibrium, and “quench” them in an amorphous, metastable glass compound, whereas slow cooling gives rise to nanocomposite film formation.

The effect of cooling rate on crystallization behavior and tensile properties of CF/PEEK composites

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Guangming Dai ◽  
Lihua Zhan ◽  
Chenglong Guan ◽  
Minghui Huang
Keyword(s):  
Cooling Rate ◽  
Crystallization Temperature ◽  
Crystallization Behavior ◽  
Crystalline Polymer ◽  
Scanning Calorimetry ◽  
Nonisothermal Crystallization ◽  
Cooling Rates ◽  
Control Range ◽  
Temperature Range ◽  
Transverse Tensile

Abstract In this study, the differential scanning calorimetry (DSC) tests were performed to measure the nonisothermal crystallization behavior of carbon fiber reinforced polyether ether ketone (CF/PEEK) composites under different cooling rates. The characteristic parameters of crystallization were obtained, and the nonisothermal crystallization model was established. The crystallization temperature range of the material at different cooling rates was predicted by the model. The unidirectional laminates were fabricated at different cooling rates in the crystallization temperature range. The results showed that the crystallization temperature range shifted to a lower temperature with the increase of cooling rate, the established nonisothermal crystallization model was consistent with the DSC test results. It is feasible to shorten the cooling control range from the whole process to the crystallization range. The crystallinity and transverse tensile strength declined significantly with the increase of the cooling rate in the crystallization temperature range. The research results provided theoretical support for the selection of cooling conditions and temperature control range, which could be applied to the thermoforming process of semi-crystalline polymer matrixed composites to improve the manufacturing efficiency.

Sign in / Sign up

Export Citation Format

Share Document