44 The effect of various cryoprotective agents and slow cooling rate on viability of goat ovarian tissue

2022 ◽  
Vol 34 (2) ◽  
pp. 257
Author(s):  
Y. M. Toishibekov ◽  
A. S. Kazybayeva ◽  
Y. A. Assanova ◽  
T. T. Nurkenov ◽  
D. Y. Toishybek
Keyword(s):  
Cooling Rate ◽  
Ovarian Tissue ◽  
Slow Cooling ◽  
Cryoprotective Agents

42 THE EFFECT OF VARIOUS CRYOPROTECTIVE AGENTS AND SLOW COOLING RATE ON VIABILITY OF SHEEP OVARIAN TISSUE

2017 ◽  
Vol 29 (1) ◽  
pp. 128
Author(s):  
A. S. Seisenbayeva ◽  
Y. M. Toishibekov ◽  
U. I. Iglmanov ◽  
B. A. Valieva
Keyword(s):  
Ovarian Tissue ◽  
Passive Cooling ◽  
Slow Cooling ◽  
Fresh Tissue ◽  
Cryoprotective Agents ◽  
Tissue Sections ◽  
Round Nucleus ◽  
Hematoxylin And Eosin ◽  
Comparative Histology

Priority objects of protection in agrobiocenoses are grades of cultural plants and local breeds of the cultivated animals. The most general criteria for preservation of local breeds are viability, adaptability, a state of health, reproductive abilities, and unique genetic polymorphism at the molecular and morphological levels. Therefore, the aim of this study was to compare the effectiveness of different cryoprotectors on morphology of ovine ovarian tissue cryopreserved by a passive cooling method. Ovarian tissue from 10 indigenous Chuyi breed was transported to the laboratory within 30 min at 32 to 34°C, divided into smaller pieces (2.0 × 1.2 × 1.0 mm), and randomly distributed into 4 groups: (1) control (fresh tissue), (2) pieces after freezing/thawing with 1.5 M ethylene glycol (EG); (3) pieces after freezing/thawing with 1.5 M propanediol (PROH); (4) pieces after freezing/thawing with 1.5 M dimethyl sulfoxide (DMSO). The ovarian pieces were placed in a cryovial and equilibrated sequentially in freezing medium containing 0.25, 0.75, and 1.5 M cryoprotectors with 0.5 M sucrose (5 min each), precooled at 4°C, and stored in a −80°C freezer for 24 h. Then, the cryovials containing the ovarian pieces were placed in liquid nitrogen and stored (for 2 months) until thawing. The ovarian pieces were cultured in vitro for 7 days in TCM-HEPES+ 10% native ovine serum (NOS) (Seisenbayeva et al. 2015 Reprod. Fertil. Dev. 28, 193–194). After 7 days of culture, we evaluated the effects of passive cooling methods with different cryoprotectors on ovarian tissue morphology by light microscopy after hematoxylin and eosin staining of tissue sections. The number of viable and damaged follicles was counted. All morphologically normal primordial, primary, and secondary follicles had healthy and intact oocytes, each containing a round nucleus and clearly visible nucleolus surrounded by well-organised granulosa cells without a pyknotic nucleus. Integrity rate of tissue after treatment was evaluated by Student’s test. In groups 1, 2, 3, and 4, the mean densities of follicles per 1 mm3 was 17.0 ± 4.6a, 16.2 ± 7.2b, 13.0 ± 5.1c, and 11.9 ± 4.8d, respectively (ab, ac, ad P > 0.05). For these groups, respectively, 69.2 ± 8.2%a , 61.7 ± 8.6%b , 52.4 ± 8.8%c and 48.5 ± 8.8%d preantral follicles were morphologically normal (ab, ac, ad P > 0.05). We did not find significant differences between groups. The analysis of comparative histology shows that 1.5 M EG is more effective on viability of ovarian follicles than 1.5 M DMSO or 1.5 M PROH.

scholarly journals Correlation of Processing, Inner Structure, and Part Properties of Injection Moulded Thin-Wall Parts on Example of Polyamide 66

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Dietmar Drummer ◽  
Steve Meister
Keyword(s):  
Cooling Rate ◽  
Injection Moulding ◽  
Degree Of Crystallinity ◽  
Process Conditions ◽  
Thin Wall ◽  
Polyamide 66 ◽  
Slow Cooling ◽  
Cooling Conditions ◽  
Internal Structures ◽  
Wall Injection

In micro- and thin-wall injection moulding the process conditions affect the developed internal structures and thus the resulting part properties. This paper investigates exemplarily on polyamide 66 the interactions of different cooling conditions on the morphological and crystalline structures. The investigations reveal that a slow cooling rate of the melt results in a homogeneous morphology and a higher degree of crystallinity and also a favoured crystalline structure. Consequently, the dielectric behaviour and light transmitting part properties are affected.

Viability of ovarian tissue after freezing

1957 ◽  
Vol 147 (929) ◽  
pp. 520-528 ◽  
Keyword(s):  
Systematic Study ◽  
Normal Saline ◽  
Ovarian Tissue ◽  
Cumulus Cells ◽  
Rapid Freezing ◽  
Freezing And Thawing ◽  
Slow Cooling ◽  
Rapid Cooling ◽  
Fertilized Egg ◽  
Cells Cultured

The fertilized egg of the rabbit, obtained from the Fallopian tube, is very sensitive to freezing and thawing, even after treatment with glycerol (Smith 1953). By contrast, the cumulus cells of the follicular granulosa which adhere to the egg after ovulation are much more resistant, and a few survive without any special precautions being taken (Smith 1949). A systematic study of the viability of the cumulus cells cultured after freezing and thawing by various methods (Smith 1953) gave the following results: (1) A majority of the cells survived when suspended in homologous serum, cooled slowly to — 79° C and thawed rapidly at + 40° C. Very few survived rapid freezing. (2) Addition of 15 % glycerol to the suspending medium improved survival after slow cooling but not after rapid cooling. (3) Cells suspended in normal saline failed to survive either slow or rapid cooling. Addition of glycerol promoted some survival after slow cooling. These experiments emphasized the need for slow cooling, already demonstrated with bull spermatozoa, and the superiority of serum over saline as a suspending medium. The addition of glycerol to the medium, though conducive to survival after freezing and thawing, was not as necessary as with spermatozoa.

Enhancing the electrical conductivity of PP/CNT nanocomposites through crystal-induced volume exclusion effect with a slow cooling rate

2020 ◽  
Vol 183 ◽  
pp. 107663 ◽  
Author(s):  
Jun Wang ◽  
Yasamin Kazemi ◽  
Sai Wang ◽  
Mahdi Hamidinejad ◽  
Mayesha B. Mahmud ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Cooling Rate ◽  
Slow Cooling ◽  
Exclusion Effect

scholarly journals Influence of Al and N Content and Cooling Rate on the Characteristics of Complex MnS Inclusions in AHSS

Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1054
Author(s):  
Muhammad Nabeel ◽  
Michelia Alba ◽  
Neslihan Dogan
Keyword(s):  
Cooling Rate ◽  
High Strength Steels ◽  
High Strength ◽  
Slow Cooling ◽  
N Content ◽  
Al Content ◽  
Advanced High Strength Steels ◽  
Cooling Conditions ◽  
Mns Precipitation ◽  
Precipitation Ratio

This study focused on the characteristics of complex MnS inclusions in advanced high strength steels. The effect of metal chemistry (Al and N) and the cooling rate of steel were evaluated by analyzing the inclusions present in five laboratory produced steels. The observed complex MnS inclusions contained Al2O3-MnS, AlN-MnS, and AlON-MnS. An increase in Al content from 0.5% to 6% increased the number of complex MnS inclusions by ~4 times. In comparison, a decrease of ~80% was observed due to the increased N content of steel from <10 ppm to ~50 ppm. MnS precipitation ratio was used to determine the potency of different inclusions forming complex MnS inclusions due to heterogeneous nucleation. It was found that the MnS precipitation ratio of the observed inclusions was related to their misfit with MnS, and it decreased in the order of AlN > AlON > Al2O3. Moreover, it was determined that AlN particles could be easily engulfed at the solidification front relative to Al2O3, which resulted in a higher MnS precipitation ratio for Al2O3 under slow cooling conditions.

40Ar/39Ar and K–Ar age constraints on shear zone evolution, southern Taltson magmatic zone, northeastern Alberta

1995 ◽  
Vol 32 (3) ◽  
pp. 281-291 ◽  
Author(s):  
H. E. Plint ◽  
M. R. McDonough
Keyword(s):  
Cooling Rate ◽  
Shear Zone ◽  
High Grade ◽  
Slow Cooling ◽  
Rapid Cooling ◽  
Deformational History ◽  
The Mean ◽  
Exhumation Rates ◽  
Northeastern Alberta ◽  
Age Constraints

New 40Ar/39Ar analyses of hornblende, muscovite, biotite, and K-feldspar constrain the timing of deformation and cooling of the southern Taltson magmatic zone, which underwent lower granulite to upper amphibolite grade deformation, in part synchronous with voluminous 1.99–1.92 Ga magmatism. New data are combined with existing K–Ar dates into a regional cooling framework to provide thermotemporal constraints on the deformational history. 40Ar/39Ar hornblende ages of ca. 1900 Ma are interpreted to record relatively rapid cooling following ductile thrusting on the Andrew Lake shear zone, and younger anatectic magmatism. These data, with published K–Ar and U–Pb data, support relatively rapid cooling of the Taltson magmatic zone from monazite closure temperature of 725 °C at ca. 1930 Ma to 525 °C at ca. 1900 Ma. Cooling rate estimates are about 7 °C/Ma, which suggests moderate exhumation rates during the high-grade part of the deformational history. A muscovite 40Ar/39Ar plateau age of 1803 ± 11 Ma is consistent with the mean muscovite K–Ar age of 1792 Ma, indicating regional cooling through about 350 °C at ca. 1800 Ma. 40Ar/39Ar ages from magmatic biotite of 1856 and 1799 Ma also suggest slow cooling during greenschist grade deformation, which can be no older than ca. 1860 Ma. A K-feldspar 40Ar/39Ar age of 1681 Ma provides a lower limit for the time of greenschist grade deformation. Cooling rate estimates during amphibolite to greenschist grade deformation are 1.75–2.25 °C/Ma.

Quench Brittleness of 12%Cr Martensitic Heat-Resistant Steel

2011 ◽  
Vol 479 ◽  
pp. 8-12 ◽  
Author(s):  
Gang Yang ◽  
Zheng Dong Liu ◽  
Shi Chang Cheng ◽  
Mu Xin Yang
Keyword(s):  
Impact Toughness ◽  
Cooling Rate ◽  
Microstructural Characterization ◽  
Temper Brittleness ◽  
Resistant Steel ◽  
Slow Cooling ◽  
Continuous Precipitation ◽  
Heat Resistant Steel ◽  
Heat Resistant ◽  
The Impact

The mechanism of brittleness due to slow cooling during quenching was experimentally investigated in 12% Cr martensitic heat resistant steel. The mechanical property tests and microstructural characterization by SEM、TEM and XRD were conducted. The results showed the impact toughness would decrease with the slowing of cooling rate during quenching, and the low cooling rate within the temperature range from 820 to 660 °C played a significant effect on the impact toughness . Different from the mechanism of temper brittleness, the main causes of embrittlement due to the slow cooling upon quenching were both the continuous precipitation of M23C6 along prior austenite grain boundaries during the process of slow cooling and that of M2C along prior residual austenite film during tempering, and this kind of quench brittleness was nonreversal.

Membrane Transport Properties of Equine and Macaque Ovarian Tissues Frozen in Mixtures of Dimethylsulfoxide and Ethylene Glycol

2007 ◽  
Vol 129 (5) ◽  
pp. 688-694 ◽  
Author(s):  
A. Kardak ◽  
S. P. Leibo ◽  
R. Devireddy
Keyword(s):  
Ethylene Glycol ◽  
Water Transport ◽  
Ovarian Tissue ◽  
Membrane Properties ◽  
Tissue Samples ◽  
Cryoprotective Agents ◽  
Tissue Sections ◽  
Ovarian Cells ◽  
Subzero Temperatures ◽  
Best Fit

The rate at which equine and macaque ovarian tissue sections are first cooled from +25°Cto+4°C has a significant effect on the measured water transport when the tissues are subsequently frozen in 0.85M solutions of glycerol, dimethylsulfoxide (DMSO), or ethylene glycol (EG). To determine whether the response of ovarian tissues is altered if they are suspended in mixtures of cryoprotective agents (CPAs), rather than in solutions of a single CPA, we have now measured the subzero water transport from ovarian tissues that were suspended in mixtures of DMSO and EG. Sections of freshly collected equine and macaque ovaries were suspended either in a mixture of 0.9M EG plus 0.7M DMSO (equivalent to a mixture of ∼5%v∕v of EG and DMSO) or in a 1.6M solution of only DMSO or only EG. The tissue sections were cooled from +25°Cto+4°C and then frozen to subzero temperatures at 5°C∕min. As the tissues were being frozen, a shape-independent differential scanning calorimeter technique was used to measure water loss from the tissues and, consequently, the best fit membrane permeability parameters (Lpg and ELp) of ovarian tissues during freezing. In the mixture of DMSO+EG, the respective values of Lpg and ELp for equine tissue first cooled at 40°C∕min between +25°C and +4°C before being frozen were 0.15μm∕minatm and 7.6kcal∕mole. The corresponding Lpg and ELp values for equine tissue suspended in 1.6M DMSO were 0.12μm∕minatm and 27.2kcal∕mole; in 1.6M EG, the values were 0.06μm∕minatm and 21.9kcal∕mole, respectively. For macaque ovarian tissues suspended in the mixture of DMSO+EG, the respective values of Lpg and ELp were 0.26μm∕minatm and 26.2kcal∕mole. Similarly, the corresponding LLg and ELp values for macaque tissue suspended in 1.6M DMSO were 0.22μm∕minatm and 31.4kcal∕mole; in 1.6M EG, the values were 0.20μm∕minatm and 27.9kcal∕mole. The parameters for both equine and macaque tissue samples suspended in the DMSO+EG mixture and first cooled at 0.5°C∕min between +25°C and +4°C were very similar to the corresponding values for samples cooled at 40°C∕min. In contrast, the membrane parameters of equine and macaque samples first cooled at 0.5°C∕min in single-component solutions were significantly different from the corresponding values for samples cooled at 40°C∕min. These results show that the membrane properties of ovarian cells from two species are different, and that the membrane properties are significantly affected both by the solution in which the tissue is suspended and by the rate at which the tissue is cooled from +25°Cto+4°C before being frozen. These observations suggest that these variables ought to be considered in the derivation of methods to cryopreserve ovarian tissues.

Connectivity and flux pinning improvements in Ag-clad BSCCO-2223 tapes produced by changes in the cooling rate

1997 ◽  
Vol 12 (11) ◽  
pp. 2997-3008 ◽  
Author(s):  
J. A. Parrell ◽  
D. C. Larbalestier ◽  
G. N. Riley ◽  
Q. Li ◽  
W. L. Carter ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Critical Temperature ◽  
Cooling Rate ◽  
Flux Pinning ◽  
Irreversibility Field ◽  
Superconducting Properties ◽  
Temperature Transition ◽  
Slow Cooling ◽  
Reaction Heat ◽  
Final Reaction

The rate at which Ag-clad (Bi, Pb)2Sr2Ca2Cu3Ox tapes are cooled from their final reaction heat treatment influences both the intergranular connectivity and intragranular flux pinning strength of the polycrystalline filaments. As the cooling rate from 825 °C to 730 °C in 7.5% O2 was decreased over a range of 5 °C/min to 0.005 °C/min, Jc (77 K, 0 T) increased from ∼8 to ∼24 kA/cm2, and the irreversibility field increased from, ∼120 to, ∼200 mT. The Jc (4.2 K, 0 T) increased in a similar fashion. Cooling slowly also sharpened the critical temperature transition and increased the critical onset temperature from 107 K to 109 K. These improvements in the superconducting properties occurred despite partial decomposition of the (Bi, Pb)2Sr2Ca2Cu3Ox phase into non-superconducting impurity phases during the slow cooling. A microstructural basis for these multiple effects is described.

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