scholarly journals Freezing goat embryos at different developmental stages and quality using ethylene glycol and a slow cooling rate

2018 ◽  
Vol 70 (5) ◽  
pp. 1489-1496 ◽  
Author(s):  
J.F. Fonseca ◽  
R.I.T.P. Batista ◽  
J.M.G. Souza-Fabjan ◽  
M.E.F. Oliveira ◽  
F.Z. Brandão ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Cooling Rate ◽  
Liquid Nitrogen ◽  
Developmental Stages ◽  
Slow Cooling ◽  
Air Bubble ◽  
Frozen Embryos ◽  
Glycol Solution ◽  
Fresh Embryos ◽  
Fresh Transfer

ABSTRACT The efficiency of an alternative freezing protocol for goat embryos of different morphology and quality was tested. Fifty-eight embryos on Day 6-7 stage were transferred as fresh or after freeze-thawing (n=29/group). For freezing, embryos were placed into 1.5M ethylene-glycol solution for 10min. During this time, they were loaded in the central part of 0.25mL straw, separated by air bubble from columns containing PBS/BSA 0.4% plus 20% BFS. Straws were then frozen using a freezing machine from 20ºC to -6ºC at a cooling rate of 3ºC/min, stabilization for 15min (seeding after 5min), from -6 C to -32ºC at 0.6 C/min,and plunged into liquid nitrogen. Frozen embryos were thawed for 30s at 37ºC in a water bath. Embryos subjected to fresh transfer were maintained in holding medium (37ºC). Fresh and frozen-thawed embryos were transferred at day 7 post-estrus to 30 recipients. Kidding and kid born rates were similar (P> 0.05), respectively, for recipients receiving fresh (66.7% or 10/15; 55.2% or 16/29) or frozen-thawed (60% or 9/15; 51.7% or 15/29) embryos. The cryopreservation of goat embryos using slow-freezing protocol and 1.5MEG resulted in similar efficiency rates of fresh embryos.

60 VITRIFICATION AND CONVENTIONAL CRYOPRESERVATION OF EQUINE EMBRYOS

2009 ◽  
Vol 21 (1) ◽  
pp. 130 ◽  
Author(s):  
J. P. Barfield ◽  
R. Sanchez ◽  
E. L. Squires ◽  
G. E. Seidel
Keyword(s):  
Ethylene Glycol ◽  
Liquid Nitrogen ◽  
Animal Health ◽  
Petri Dish ◽  
Water Bath ◽  
Slow Freezing ◽  
Slow Cooling ◽  
Cooling Method ◽  
Frozen Embryos ◽  
Rectal Palpation

Vitrification and conventional cryopreservation are effective methods of preserving equine embryos smaller than 300 μm in diameter. This study was designed to compare pregnancy rates using these methods to cryopreserve embryos of similar size. Sport horse mares approximately 2–20 years old were flushed nonsurgically between Days 6.5 and 7 post-ovulation with 2 L of lactated-Ringers solution (Braun, Melsungen, Germany). Thirty-one embryos were collected, washed 4 times with 1 mL of ViGro® holding medium (Bioniche Animal Health, Bogart, GA), graded for quality, measured for diameter, and blocked into 2 groups (<200 μm, 200 to 300 μm). Embryos were either vitrified with a commercial equine vitrification kit (Bioniche Animal Health) according to the manufacturer’s instructions in 0.25-mL straws or subjected to a slow cooling method. For vitrification, embryos were sequentially transferred to 2 wells containing 0.5 mL of 2 Syngro®-based vitrification solutions (VS1 and VS2) and held for 5 min each. Embryos were incubated in a third vitrification solution (VS3) for 45 s during which time they were loaded into straws. Straws were held in liquid nitrogen-cooled air for 1 min before submersion in liquid nitrogen. For slow freezing, embryos were consecutively placed into 0.5 mL of the following Syngro®-based solutions for 5 min each: 1.8 m glycerol, 1.8 m glycerol + 1.8 m ethylene glycol (EG), and 0.9 m glycerol + 0.9 m EG + 0.5 m galactose. Embryos were loaded into 0.25-mL straws, placed in a chamber pre-cooled to –6°C, and held for 10 min. Straws were seeded after 2 min. The temperature was lowered to –32°C at a rate of 0.5°C min–1. Embryos were then plunged into liquid nitrogen within 3 min of reaching –32°C. For warming vitrified embryos, straws were held in air for 10 s followed by submersion into a 35°C water bath for 20 s. Straws were flicked 5 times to mix the diluent solution with the VS3-containing embryos, which were transferred within 7 min of being thawed. For thawing conventionally frozen embryos, straws were held in air for 10 s followed by submersion into a 35°C water bath for 30 s. Contents of the straw were immediately expelled into a Petri dish, and the embryos were transferred immediately to 0.5 mL of 1.2 m glycerol +1.2 m EG + 0.5 m galactose and held for 5 min. This was followed by a 5-min incubation in 0.5 mL of each of the following solutions: 0.6 m glycerol + 0.6 m EG + 0.5 m galactose, 0.25 m glycerol + 0.25 m EG + 0.5 m galactose, and 0.5 m galactose. After exposure to the last solution, embryos were transferred to Syngro®, loaded into a straw, and immediately transferred into 2-year-old virgin recipients 6 days after ovulation as detected by rectal palpation and ultrasonography. Of the 21 embryos <200 μm collected, 11 were vitrified and 10 frozen slowly. Three of these 11 vitrified embryos and 7 of 10 slow-frozen embryos resulted in Day 16 pregnancies (27 and 70%, respectively). None of the embryos >200 μm resulted in pregnancies in either the vitrification (n = 5) or slow-freeze treatments (n = 4).

scholarly journals 97 ASSESSMENT OF VIABILITY OF IN VITRO PRODUCED BOVINE EMBRYOS FOLLOWING VITRIFICATION BY CVM OR SLOW FREEZING WITH ETHYLENE GLYCOL AND TRIPLE TRANSFER

2005 ◽  
Vol 17 (2) ◽  
pp. 199 ◽  
Author(s):  
B. Peachey ◽  
K. Hartwich ◽  
K. Cockrem ◽  
A. Marsh ◽  
A. Pugh ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Survival Rates ◽  
Slow Freezing ◽  
High Survival ◽  
Bovine Embryos ◽  
Embryo Survival ◽  
Frozen Embryos ◽  
Morula Stage ◽  
Fresh Embryos

Vitrification has become the method of choice for the preservation of in vitro derived embryos of a number of species, and several methods of vitrification have been developed. One such method, the cryoLogic vitrification method (CVM) yields high survival rates of warmed embryos (Lindemans W et al. 2004 Reprod. Fertil. Dev. 16, 174 abst). In this study, the post-warm viability of bovine IVP embryos following either vitrification using CVM or slow freezing using ethylene glycol (EG) was compared. In addition, the survival of embryos following triple transfer to synchronized recipients was measured and the embryo (“e”) and recipient (“r”) contributions to embryo survival was determined using the “er” model for embryo survival (McMillan WH et al. 1998 Theriogenology 50, 1053–1070). Bovine IVP methods were those of van Wagtendonk et al. 2004 Reprod. Fertil. Dev. 16, 214 (abst). On day 7 of culture (Day 0 = IVF), Grade 1 and 2 embryos that had reached at least the late morula stage were selected for vitrification (20% DMSO, 20% ethylene glycol) or freezing in 1.5 M ethylene glycol + 0.1 M sucrose (0.5°C/min to −35°C). Following storage in LN2 for at least 24 h the embryos were thawed, the cryoprotectant removed, and the embryos cultured for 72 h in mSOF medium under 5% CO2, 7% O2, 88% N2. The number of hatching embryos was recorded at 24-h intervals. In addition, blastocyst and expanded blastocyst embryos were thawed and immediately transferred nonsurgically to recipients (three embryos of the same grade to each recipient) on Day 7 of a synchronized cycle (Day 0 = heat). The recipients were ultrasound-scanned for the presence of, and number of, fetuses on Days 35 and 62, respectively. The invitro assessment of 148 CVM and 230 EG frozen embryos indicated that more vitrified than EG embryos hatched by 72 h (73% vs. 62%; CVM vs. EG, χ2 = 4.5, P < 0.05). Overall, more Grade 1 embryos hatched than Grade 2 (74% vs. 60%, χ2 = 7.2, P < 0.01). CVM embryos (105) were triple-transferred to 35 recipients, and EG embryos (30) were triple-transferred to 10 recipients. Recipient pregnancy rates at Day 62 were 80% and 70%, respectively. Overall embryo survival was 38.5% (41% for CVM and 30% for EG). The overall calculated “e” and “r” values were 0.39 and 1.0 (“e”: 0.42 and 1.0, and “r”: 0.31 and 1.0, respectively, CVM and EG groups). Survival rates of CVM embryos to Day 62 (41%) were slightly lower than that previously obtained for fresh embryos produced using an identical IVP procedure (44% – van Wagtendonk AM 2004).

85 VITRIFICATION IN VIVO OF LARGE EQUINE EMBRYOS AFTER VITRIFICATION OR CULTURE

2006 ◽  
Vol 18 (2) ◽  
pp. 151 ◽  
Author(s):  
L. F. Campos-Chillon ◽  
T. J. Cox ◽  
G. E. Seidel Jr ◽  
E. M. Carnevale
Keyword(s):  
Ethylene Glycol ◽  
Pregnancy Rate ◽  
Liquid Nitrogen ◽  
Slow Cooling ◽  
Small Column

Cryopreservation of large (>300 μm) equine embryos has been unsatisfactory using slow-cooling or vitrification techniques. The objective of the present experiments was to compare three methods for vitrification of large embryos using modified vitrification protocols for equine (Eldridge-Panuska et al. 2005 Theriogenology 63, 1308–1319) and bovine (2003 J. Anim. Sci. 81 Suppl. 1, 143) embryos. For Method 1, embryos (n = 14) 350–550 or 550–750 µm were exposed, respectively to, VS1 [1.4 M glycerol (G) in mPBS] for 5 min or 7 min, moved to VS2 [1.4 M G, 3.6 M ethylene glycol (EG) in mPBS] for 5 min or 7 min, and then transferred to VS3 (3.4 M G, 4.6 M EG in mPBS) for 40 or 60 s. In Method 2, embryos (n = 13) 350–550 or 550–750 μm were exposed, respectively, to VS1 for 10 or 14 min, VS2 for 10 or 14 min and VS3 for 60 or 90 s. Straws (0.25 mL) for Methods 1 and 2 were loaded with two columns of DS (0.5 M galactose in mPBS) and a small column of VS3 containing the embryo. Straws were heat-sealed and deposited in a goblet suspended in liquid N2 and containing vapor for 1 min and then plunged. Straws were warmed in air (24°C) for 10 sec and then in water at 20°C for 10 sec. Straws were shaken to mix the columns; after 3 min, embryos were expelled and re-hydrated in two additional solutions containing 0.3 and 0.15 M galactose for 3 min each. For Method 3, embryos (n = 17) 300–750 μm were placed in 1.5 M EG in mPBS for 5 min; 3 M EG in mPBS for 10 min; 5 M EG in mPBS for 5 min and 7 M EG, 0.5 M galactose, 18% w/v Ficoll 70 in mPBS for less than a minute. The droplet containing an embryo was loaded into a 0.25 mL straw that was preloaded with two columns of DS and followed by a small column of DS. Straws were heat-sealed and plunged vertically, sealed end fist, into liquid nitrogen covering the embryo, then the remainder of the straw was slowly immersed. Straws were warmed in air (24°C) for 10 s and then in water at 37°C for 10 s. Straws were shaken to mix the columns; after 3 min at 37°C, embryos were rehydrated as in Methods 1 and 2. Embryos were transferred nonsurgically to recipients 5 d after ovulation, and pregnancy diagnoses were performed 5 to 9 d after transfers. No embryonic vesicles were observed for embryos vitrified with Methods 1 and 2. The pregnancy rate for embryos vitrified with Method 3 was 35% (6/17) overall, and 55% (6/11) for embryos between 300–400 μm. No pregnancies resulted from embryos >400 μm. More studies are needed to optimize methodologies for dehydration, equilibration, and warming of large equine embryos.

135 IN VITRO DEVELOPMENT OF IN VIVO PRODUCED EMBRYOS FROZEN AT MORULA OR BLASTOCYST STAGES

2008 ◽  
Vol 20 (1) ◽  
pp. 148
Author(s):  
R. Sartori ◽  
G. M. Machado ◽  
M. M. Guardieiro ◽  
M. R. Bastos ◽  
L. Leme ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Liquid Nitrogen ◽  
Zebu Cattle ◽  
Hatching Rate ◽  
Chi Square ◽  
Fluid Medium ◽  
Chi Square Test ◽  
Fresh Embryos

This study was designed to compare cryotolerance between morulae and blastocysts collected from superovulated heifers. Twenty pubertal beef heifers (10 Nelore and 10 crossbred Nelore � Simmental) were superovulated with 100 mg of FSHp (Folltropin-V, Bioniche, Ontario, Canada), and embryos were collected and evaluated 7 days after estrus. Grades 1 and 2 embryos (IETS) were divided into four groups: morulae cryopreserved (MC) in liquid nitrogen (n = 24); blastocysts cryopreserved (BC; n = 19); morulae fresh (MF; n = 23); and blastocysts fresh (BF; n = 18). For freezing, embryos were immersed in ethylene glycol (Ethylene Glycol Freeze Plus with 0.1 m sucrose, Bioniche, Pullman, WA, USA), and a standard protocol (cooling rate of –0.5�C/min) was used. Prior to in vitro culture, embryos were removed from nitrogen, kept at room temperature for 5 s, and put in a water bath at 30�C for 20 s. Within 5 h after recovery, thawed and fresh embryos were washed five times in holding solution (Holding Plus, Bioniche), transferred to synthetic oviduct fluid medium (SOF, Nutricell, Campinas, SP, Brazil), and cultured for 72 h. Embryos were evaluated at 48 and 72 h of culture. After the last evaluation, degenerate and non-hatched embryos were removed from culture, and the remaining embryos were measured by a graduated ocular coupled to the Motic Images Plus 2.0 program. Hatched blastocysts were kept in culture for an additional 48 h for post-hatching development assessment. For post-hatching culture PHD medium (Brand�o DO et al. 2005 Biol. Reprod. 71, 2048–2055) was added into each well, to have a final composition of 50% SOF and 50% SOF PHD. At 120 h of culture (48 h of PHD culture) only morphologically normal blastocysts were measured. Comparison among groups was performed by ANOVA or chi-square test. Data are presented as mean � SEM. After 48 h of culture, hatching rate (%) was significantly lower in cryopreserved (MC = 8.3 and BC = 21.5) than in fresh (MF = 56.5 and BF = 77.8) embryos (P < 0.05). However at 72 h, hatching rate was similar among BC (75.9), MF (78.3), and BF (88.9), being MC (41.7) still lower (P < 0.05). The diameter (µm) of hatched embryos after 72 h of culture was 272.8 � 27.1a (n = 8), 320.6 � 18.6ab (n = 14), 385.3 � 14.2c (n = 17), and 378.0 � 22.0bc (n = 16) for MC, BC, MF, and BF, respectively (a–cP < 0.05). After 120 h of culture, the diameter of MC (379.0 � 39.9; n = 8), although similar to BC (495.4 � 59.6; n = 10), was smaller than MF (509.1 � 36.5; n = 11) and BF (511.8 � 41.2; n = 14). The results of this study with zebu cattle suggest that morulae are less resistant to cryopreservation in liquid nitrogen than blastocysts. Moreover, frozen/thawed embryos, when put in culture, present a slower development compared with fresh embryos. Financial support from CNPq and FAPESP from Brazil.

scholarly journals Comparison of two vitrification methods for cryopreservation of porcine embryos

2011 ◽  
Vol 49 (No. 5) ◽  
pp. 183-189
Author(s):  
J. Říha ◽  
J. Vejnar
Keyword(s):  
Ethylene Glycol ◽  
Liquid Nitrogen ◽  
Artificial Insemination ◽  
Culture Medium ◽  
Calf Serum ◽  
Foetal Calf Serum ◽  
Post Mortem ◽  
Donor Insemination ◽  
Viable Embryo ◽  
Fresh Embryos

The aim of this study was to compare two vitrification methods of porcine perihatching blastocysts with regard to the success of transfer of these embryos to the recipients. Expanded, hatching, or hatched blastocysts were recovered post mortem from superovulated donors in 5.5 to 6.0 days after artificial insemination of donor gilts with homospermic doses. In protocol VS I, the embryos in perihatching developmental stage were equilibrated in a culture medium H-MEMD with 10% v/v of glycerol (1.37M solution of glycerol in medium) for 10 min and placed in a vitrification medium for 1.5 min max. (vitrification medium contained 50% v/v 2M sucrose in tridistilled water, 30% v/v of glycerol, and 20% v/v of foetal calf serum &ndash; FCS). Then they were dropped with micropipette and stored in liquid nitrogen vapour. For protocol VS II, we used H-MEMD culture medium supplemented with 20% v/v of FCS, 25% v/v ethylene glycol, and 25% v/v dimethyl sulphoxide (DMSO). Embryos were equilibrated for 10&nbsp;min in a mixture of the vitrification medium and culture medium (1 : 1), and were kept in the vitrification medium for 1.5&nbsp;minutes. Then they were dropped with micropipette and stored in liquid nitrogen vapour. Embryos were thawed by immersing the drop with the embryo in H-MEMD culture medium with 0.8M sucrose for 10 minutes. After thawing and washing in the medium with sucrose, all embryos were washed three times in a fresh medium and prepared for transfer. Recipients were synchronized either using Regumate-feeding followed by treatment with PMSG and HCG (gilts) or using piglet weaning (sows &ndash; 1st and 2nd parity). Recipients showing standing heat at the time of donor insemination were used for laparoscopic and non-surgical ET on day 5.5&ndash;6.0 of the cycle. The fraction of viable embryo vitrified under VS I or VS II protocol was 85% and 80%, compared to 95% in control fresh embryos (P &gt; 0.05). Pregnancy of recipients was 57.3% (5/7), 67.0% (4/6) for VS I or VS II group and 42.7% (10/23) for control (P &lt; 0.001). We can conclude on the basis of our data that both protocols for vitrification yielded similar results and can be used for cryopreservation of porcine embryos. &nbsp;

scholarly journals 120PREGNANCY RATES RESULTING FROM TRANSFER OF FRESH AND FROZEN HOLSTEIN AND JERSEY EMBRYOS

2004 ◽  
Vol 16 (2) ◽  
pp. 182 ◽  
Author(s):  
R. Steel ◽  
J.F. Hasler
Keyword(s):  
Ethylene Glycol ◽  
Dairy Farms ◽  
Pregnancy Rates ◽  
Embryo Survival ◽  
Embryo Freezing ◽  
Retrospective Comparison ◽  
Frozen Embryos ◽  
Embryo Stage ◽  
In Pregnancy ◽  
Fresh Embryos

Although it has not been documented in published studies, embryo transfer (ET) practitioners have suggested that embryos from Jersey (JE) cattle do not survive freezing as well as embryos from other dairy breeds such as Holsteins (HO). The present study represents a retrospective analysis of pregnancy rates achieved following transfer of fresh and frozen embryos from Jersey and Holstein donors. In addition, a retrospective comparison was made of two different embryo-freezing protocols for each breed of cattle. Embryos were collected nonsurgically 7 to 7.5 days post-estrus from superovulated donors on 57 Holstein and 27 Jersey dairy farms over a 15-year period. Fresh and frozen-thawed embryos were transferred nonsurgically into cows and heifers following either natural or prostaglandin-induced estrus. Embryos were frozen either in 10% glycerol (Gly) or 1.5M ethylene glycol (EG) in 0.25mL straws. Following equilibration, straws were seeded at −6 to −7°C and temperature was maintained for 10 min and then decreased at 0.6°Cper min. Straws were plunged into liquid nitrogen at −32 to −35°C. At thawing, straws were held in the air for 7s and then submerged in 29°C water for 15s. Embryos frozen in EG were transferred immediately following thawing. Embryos frozen in Gly were rehydrated in a standard 3-step Gly-sucrose system prior to being transferred. Pregnancy diagnosis was performed at Days 40 to 90 of gestation. As seen in the Table 1, pregnancy rates were similar for fresh embryos from both HO and JE cattle. Also, there were no differences in pregnancy rates between recipients that received embryos frozen in Gly or EG within donors of either breed. However, JE embryos frozen in either Gly or EG resulted in lower pregnancy rates than did HO embryos frozen in Gly or EG. Embryo stage at freezing was tracked for EG but not Gly embryos. There were no differences in pregnancy rates among morulae, early blastocysts or mid-blastocysts for either HO or JE embryos frozen in EG. The differences in embryo survival may be due to different lipid composition of embryos of the two breeds. Perhaps a more efficacious freezing protocol can be developed for cryopreservation of JE embryos. In conclusion, pregnancy rates with cryopreserved HO embryos were higher than with JE embryos. Table 1

scholarly journals Interferon tau secretion in cattle embryos in vitro fertilized before and after cryopreservation

2005 ◽  
Vol 57 (6) ◽  
pp. 752-756
Author(s):  
M.C.C. Araújo ◽  
V.R. Vale Filho ◽  
A.M. Ferreira ◽  
W.F. Sá ◽  
J.B. Barreto Filho ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Media Culture ◽  
Bovine Embryos ◽  
Interferon Tau ◽  
Individual Culture ◽  
Frozen Embryos ◽  
Before And After ◽  
The Media ◽  
Fresh Embryos

The effect of cryopreservation in IFN-tau, from bovine embryos produced in vitro was evaluated. Two treated groups (G1= fresh bovine embryos, n=59 and G2= freezed embryos, n=84) were used to study the effect of cryopreservation on IFN-tau secretion. After reaching the blastocyst phase, the embryos were kept on individual culture for additional period of 7 days. On days 3 and 7 after the beginning of embryos cultivation, samples of the media culture were taken for IFN-tau secretion titration. Oocysts taken from follicles ranging from 3 to 5mm in diameter were obtained from ovaries of females at slaughterhouse. The embryos were frozen, after being dehydrated with ethylene glycol (1.8m), conditioned on 0.5ml palletes and frozen. Frozen embryos secreted lower IFN-tau than fresh embryos (P<0.05). At day 7 it was registered higher IFN-tau secretion from trophoblast than at day 3 (P<0.05). The increasing of IFN-tau secretion was observed when the blastocyst began to longed and it was directly related to the embryos development. The synthesis of IFN-tau is related to the capability of development of the blastocyst. Cryopreservation is a method that affects the maternal recognition of pregnancy and the post-freezing embryo development.

Production of bovine cloned embryos with donor cells frozen at a slow cooling rate in a conventional freezer (−20 °C)

Zygote ◽  
2009 ◽  
Vol 17 (4) ◽  
pp. 341-351 ◽  
Author(s):  
Liliana Chacón ◽  
Martha C. Gómez ◽  
Jill A. Jenkins ◽  
Stanley P. Leibo ◽  
Gemechu Wirtu ◽  
...  
Keyword(s):  
Low Temperature ◽  
Cooling Rate ◽  
Liquid Nitrogen ◽  
First Generation ◽  
Blastocyst Stage ◽  
Live Cells ◽  
First Passage ◽  
Slow Cooling ◽  
Donor Cells ◽  
Bovine Oocytes

SummaryUsually, fibroblasts are frozen in dimethyl sulphoxide (DMSO, 10% v/v) at a cooling rate of 1 °C/min in a low-temperature (−80 °C) freezer (LTF) before storage in liquid nitrogen (LN2); however, a LTF is not always available. The purpose of the present study was to evaluate apoptosis and viability of bovine fibroblasts frozen in a LTF or conventional freezer (CF; −20 °C) and their subsequent ability for development to blastocyst stage after fusion with enucleated bovine oocytes. Percentages of live cells frozen in LTF (49.5%) and CF (50.6%) were similar, but significantly less than non-frozen control (88%). In both CF and LTF, percentages of live apoptotic cells exposed to LN2 after freezing were lower (4% and 5%, respectively) as compared with unexposed cells (10% and 18%, respectively). Cells frozen in a CF had fewer cell doublings/24 h (0.45) and required more days (9.1) to reach 100% confluence at the first passage (P) after thawing and plating as compared with cells frozen in a LTF (0.96 and 4.0 days, respectively). Hypoploidy at P12 was higher than at P4 in cells frozen in either a CF (37.5% vs. 19.2%) or in a LTF (30.0% vs. 15.4%). A second-generation cryo-solution reduced the incidence of necrosis (29.4%) at 0 h after thawing as compared with that of a first generation cryo-solution (DMEM + DMSO, 60.2%). The percentage of apoptosis in live cells was affected by cooling rate (CF = 1.9% vs. LFT = 0.7%). Development of bovine cloned embryos to the blastocyst stage was not affected by cooling rate or freezer type.

Electrochemical micromachining of ZrCu-based amorphous alloy in ethylene glycol solution

2021 ◽  
Vol 132 ◽  
pp. 107155
Author(s):  
Hang Yusen ◽  
Yang Tao ◽  
Xu Zhengyang ◽  
Zeng Yongbin
Keyword(s):  
Amorphous Alloy ◽  
Ethylene Glycol ◽  
Electrochemical Micromachining ◽  
Glycol Solution

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.

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