The impact of lyophilization media on fertilization potential of buffalo spermatozoa.

It is one of important design issues in the high-temperature superconducting fault current limiter (HTS-FCL) to estimate how much liquid nitrogen vaporizes during its quench process. This paper describes the small scale experiment about the vaporization of subcooled liquid nitrogen by instantaneous heat generation corresponding to the quench in HTS-FCL. In the experiment, the heat is given liquid nitrogen by Joule heating of the stainless steel strip for the short time of about 100 ms. The time variations of temperature and pressure in the liquid nitrogen test chamber are measured for different subcooling conditions of liquid nitrogen and various heat flux conditions. In addition, the amount of vaporization of liquid nitrogen is calculated from experimental results according to the subcooling of liquid nitrogen. The experimental results show that the vaporization of liquid nitrogen strongly depends on heat flux and subcooling conditions. The amount of vaporization linearly decreases with the increase in the subcooling of liquid nitrogen. The calculation results about the amount of vaporization suggest that the subcooling of more than 20 K is necessary to suppress bubble generation for the heat flux condition of 46 W/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> or more.

610 Method of differential breast tumour diagnostics

The effect of freeze-drying media and storage temperature on ultrastructure and DNA of freeze-dried buffalo bull spermatozoa

Infectious organisms such as hepatitis B were recently shown to survive in liquid nitrogen. To prevent cross-contamination of semen samples via liquid nitrogen, studies were undertaken to evaluate human sperm survival in the vapor phase of liquid nitrogen at -189 degrees C. The study was conducted in 2 separate experiments. In the first experiment, a total of 30 unwashed, fresh semen samples (15 normozoospermic and 15 oligozoospermic) were evaluated for motility, vitality, and morphology after freeze-thaw survival in vaporous (-189 degrees C) and liquid nitrogen (-196 degrees C; control) phases. Similar evaluations were carried out in a second experiment on 27 samples (15 normozoospermic and 12 oligozoospermic) that were previously washed by the swim-up method. Motile sperm recovery rates were significantly different between liquid and vapor phases (unwashed, normozoospermic: 42.76% +/- 3.23% vs 45.52% +/- 4.44%, P < .05; washed, normozoospermic: 34.44% +/- 4.41% vs 37.58% +/- 3.90%, P < .05; unwashed, oligozoospermic: 16.53% +/- 3.34% vs 18.25% +/- 4.36%, P < .05; washed, oligozoospermic: 10.32% +/- 2.54% vs 12.25% +/- 2.81%, P < .05). Recovery rates for motility were much higher for unwashed samples compared with washed semen samples. In all experiments the recovery of normal and live forms showed no significant differences between the vapor and liquid nitrogen storage phases (P > .05). The results demonstrate that both washed and unwashed human sperm survive satisfactorily with good recovery in the vapor of liquid nitrogen and can be recommended for future storage in medically assisted conception programs.

Societal implications of herpes simplex virus (HSV) in semen donors.

Comparison of cryopreserved human sperm in vapor and liquid phases of liquid nitrogen: effect on motility parameters, morphology, and sperm function

Liquid nitrogen vapor is comparable to liquid nitrogen for storage of cryopreserved human sperm: evidence from the characteristics of post-thaw human sperm

Human motile sperm recovery after cryopreservation: freezing in nitrogen vapor vs the direct plunge technique

Optimizing incubation conditions for the preservation of sperm motility in processed semen samples

What is the lowest optimal semen volume for cryopreservation test vials?

Sperm cryosurvival using minimal semen volume in test vial

Suitability of the hypo-osmotic swelling test for assessing the viability of cryopreserved sperm

The goaf is the main disaster area for natural fires in mines, and liquid nitrogen has become an essential medium for fire prevention in goafs due to its excellent cooling and inerting properties.At present, there is no in-depth research on the transport and vaporization of liquid nitrogen after injection into the goaf, and it is impossible to quantitatively evaluate the cooling inerting effect after liquid nitrogen injection. To address the above problems, this project proposes to carry out the following research: to study the effects of different inclination angles on the transport and vaporization of liquid nitrogen and temperature distribution in the loose medium in confined space by monitoring the temperature field changes during the pressure injection of liquid nitrogen in the loose medium in confined space.The results show that the temperature field distribution is very uneven after liquid nitrogen is injected into the loose medium in the restricted space.It is found that the vaporization rate of liquid nitrogen decreases with the increase of diffusion time and diffusion area, and the instantaneous vaporization rate of liquid nitrogen decreases with the larger inclination angle under the same injection position. Compared with the horizontal state, the maximum vaporization rate decreased 84.79% when the maximum inclination angle was 15°, which indicates that the vaporization rate was greatly affected by the inclination angle of the surface. In the vertical direction of the experimental box, the cooling area of liquid nitrogen in the experimental box is mainly concentrated within 0.05 m height from the bottom of the experimental box, and the changes of the “cooling restricted zone” after liquid nitrogen injection into the goaf are further explained during the experiment.It is found that the “cooling restricted zone” mainly exists in the upper part of the goaf, under the inclined condition, and the area increases with the increase of the inclination angle, so the increase of the angle is not conducive to the effective cooling effect of liquid nitrogen.The research results of the project will help to improve the theory of liquid nitrogen fire prevention in mines and provide theoretical support for the fire prevention technology of liquid nitrogen direct injection in goafs.

Biological diversity is the key to maintaining life. Therefore preservation of biodiversity is important for sustaining a healthy Earth, but it also is immensely valuable tothe health and lifestyle of human society. Today new methods of auxiliary reproductivetechnology allow using them not only for preservation of reproductive potential of theperson, and also for preservation a biodiversity of wild and endangered species of farmanimals. Captive breeding programs, genetic resource banks and artificial reproductivetechniques have been suggested as important tools for conservation. Today, biotechnological methods, such as artificial insemination and transplantation of embryos are welldeveloped and are used in programs of animal husbandry and preservation. Receivingoocytes and embryos requires stimulation of ovaries on what some time depending ona species of animals usually is required. These methods are not acceptable in case ofemergency, and the in vivo received oocytes in smaller quantity do not guarantee themaximum storage of genetic material. Therefore an alternative method of preservation ofgenetic material is the cryopreservation of immature oocytes in the primordial follicleswhich are located in ovary cortex. The procedure of ovarian tissue cryopreservation permits conservation of hundreds of immature oocytes kept within the protective environment of the original ovarian tissue. An important advantage of this technique that thehormonal stimulation is not required in this case. Additionally, because the primordialfollicles are small and have a simple structure, they are much more tolerant to manipulation and to the freeze-thaw procedure compared with the large growing follicles. A keyelement of a good cryopreservation to cell survival is the physiochemical relationshipof heat and water transport between the intra- and extracellular environment. The art ofcryobiology involves the addition of one or more cryoprotectants which generally reduceboth the eutectic and freezing points. Therefore the purpose of this work is identificationof an optimum method of a cryopreservation of sheep‘s ovarian tissue using of variouscryoprotectors. In the present study, the cryopreservation of indigenous Chui population sheep’s ovarian tissue was conducted in vapors of liquid nitrogen at distance of 5cm from surface within 20 minutes with use of various cryoprotectors: 1,5 M dimethylsulfoxide (DMSO), 1,5 M propylene glycol (PG), 1,5 M ethylene glycol (EG) and 1,5 Mglycerol (HL). The analysis of comparative histology studying shows that use 1,5 M PGand 1,5 M DMSO has more effective effect on viability of ovarian follicles, than use 1,5M EG and 1,5 M HL.Key words: dimethyl sulfoxide, ethylene glycol, freezing, follicles, glycerol, ovariantissue, propylene glycol.

Simple SummaryThe germplasm banks of wild species, such as Iberian red deer, are not widespread, mainly due to the difficulties of collecting and cryopreserving reproductive cells. Optimal freezing protocols under field conditions could be a breakthrough for these species. In this study, epididymal sperm was evaluated using two methods of sperm storage during refrigeration (tube and straw); four equilibration periods (0, 30, 60, and 120 min); and four methods of freezing (cryopreservation in liquid nitrogen vapors in a tank (control) or box, freezing in dry ice, or freezing over a metallic plate). The results showed that samples stored in straws during refrigeration produced less apoptotic spermatozoa and more viable spermatozoa withactive mitochondria. A long equilibration period (120 min) yielded a higher percentage of acrosomal integrity. Moreover, there was no difference in sperm quality between freezing in liquid nitrogen vapors in a tank or box. However, a worse quality was obtained when the samples were cryopreserved in dry ice or over a metallic plate compared to the control. Creating germplasm banks of wild species, such as the Iberian red Deer (Cervus elaphus hispanicus) can be challenging. One of the main difficulties is the obtention and cryopreservation of good-quality reproductive cells when the spermatozoa are obtained from epididymides after death. To avoid a loss of seminal quality during transport, developing alternative methods for cooling and freezing sperm samples under field conditions is necessary. The objective of this study was to evaluate the effects of different durations of equilibrium and different techniques of cooling and freezing on Iberian red deer epididymal sperm quality after thawing to optimize the processing conditions in this species. Three experiments were carried out: (I) evaluation of refrigeration in straws or tubes of 15 mL; (II) study of equilibration period (0, 30, 60, or 120 min); and (III) comparison of four freezing techniques (liquid nitrogen vapor in a tank (C), liquid nitrogen vapor in a polystyrene box (B), dry ice (DY), and placing straws on a solid metallic plate floating on the surface of liquid nitrogen (MP)). For all experiments, sperm motility and kinematic parameters, acrosomal integrity, sperm viability, mitochondrial membrane potential, and DNA integrity were evaluated after thawing. All statistical analyses were performed by GLM-ANOVA analysis. Samples refrigerated in straws showed higher values (p ≤ 0.05) for mitochondrial activity and lower values (p ≤ 0.05) for apoptotic cells. Moreover, the acrosome integrity showed significant differences (p ≤ 0.05) between 0 and 120 min, but not between 30 and 60 min, of equilibration. Finally, no significant differences were found between freezing in liquid nitrogen vapors in a tank or in a box, although there was a low quality after thawing when the samples were cryopreserved in dry ice or by placing straws on a solid metallic plate floating on the surface of liquid nitrogen. In conclusion, under field conditions, it would be possible to refrigerate the sperm samples by storing them in straws with a 120 min equilibration period and freezing them in liquid nitrogen vapors in a tank or box.