Cryopreservation Research Articles

The Roles of Ni and Co in Dendritic Growth and Tensile Properties of Fe‐Containing Al–Si–Cu–Zn Scraps under Slow and Fast Solidification Cooling

Studies of Fe‐contaminated Al‐based scraps have drawn attention for years. However, little has been researched about the effects of cobalt (Co) and nickel (Ni) additions to contaminated scraps both under slow solidification (directional solidification, DS) and fast solidification regime (copper mold centrifugal casting, CC). As such, the current study examines a representative low‐alloy Al–Si chemistry from industrial scraps, i.e., the Al–7%Si–0.6%Fe–0.35%Cu–0.25%Zn (% by weight). This alloy is changed independently using Ni and Co. It is observed that a mixture of uneven distributed α and β Fe‐bearing particles prevails for all tested alloys and solidification conditions. The coexistence of both phases agrees with the charts proposed by Gorny's work for the range of secondary dendritic spacing, λ 2, observed. Although the Fe‐containing particles are smaller for fast‐solidified samples, they still maintain the acute morphology and, in some cases, the Chinese script shape. This results in a reduction in ductility of the order of 65% for the nonmodified and Ni‐modified samples considering mean λ 2 varying from 20 μm (DS) to 6.5 μm (CC), despite improvements in mechanical strength. Furthermore, addition of Co results in a higher number of Fe‐based particles within the microstructure. In this case, the largest particle/α‐Al interfacial area results in slightly poor ductility (~6–8%) and higher strength (175–205 MPa), with less ductility loss when DS and CC samples are compared.

MOTILITY AND TOTAL MOTILE COUNT DECLINE OBSERVED WITH A NOVEL MAIL-IN SEMEN CRYOPRESERVATION SYSTEM

To define (1) the freeze-thaw recovery rate from semen samples incubated at shipping temperatures and (2) the effect of delayed cryopreservation (CRYO) on the recovered total motile count (TMC) compared to standard immediate CRYO utilizing a previously validated semen transport system.

Experimental measurements and thermodynamic modeling of freezing points in the systems Na+//Cl−, SO42−, NO3−–H2O and Na+, K+//Cl−, NO3−–H2O

The freezing (eutectic) point data at various water concentrations (95, 85 and 75 wt%) of different solution composition in systems Na+//Cl−, SO42−, NO3−–H2O and Na+, K+//Cl−, NO3−–H2O were studied by cooling curves method. Based on the experimental data, the freezing (eutectic) temperature-solution composition diagrams were constructed, which showed that the freezing point decreased with decreasing water content independent of kinds of salts and also influenced by the solubility of salt. The freezing (eutectic) point of the systems was carried out with extended UNIQUAC model. We compared the performance of the model with the data obtained by the experimental, the present results confirm the model as a good choice to calculate the freezing point considering the processing conditions that no large amount of salt precipitated from the solution. In general, the model accuracy was satisfactory. The results better revealed the relationship between the freezing point and the salt/water content in brine at low temperature, and can offer fundamental data to provide important theoretical guidance for the research of brine cryogenic freezing technology.

Heat transfer modeling of shrimp in tunnel type individual quick freezing system

AbstractCryogenic freezers are commonly used for quick freezing of high‐value food products at a lower temperature. These freezers offer improved overall product quality and reduced dehydration and drip losses. An accurate prediction of heat transfer during the food freezing process is useful in deciding proper production, design, handling procedure, and amount of cryogen required. In this study, computational fluid dynamics (CFD) was used for numerical modeling of heat transfer phenomena in a freezing system during individual quick freezing (IQF) of shrimp. The residence time of shrimp in the developed IQF tunnel freezer was determined using modified Plank's equation and verified by experimentations. Modeling was done in two zones of the freezer: (i) Precooling zone containing cold liquid nitrogen (LN2) vapors that were utilized for precooling of incoming shrimp and (ii) freezing zone where LN2 was sprayed on shrimp before exiting freezer. Simulations of heat transfer in shrimp were performed using the Ansys CFD software at seven different locations of the IQF tunnel freezer. Results revealed that the core temperature of shrimp decreased from 304.5 K to 263 K as it passes through the freezer. In general, as compared to other segments of shrimp, core temperature of shrimp was the highest while the top portion was minimal. Dynamics of velocity distribution, thermal profile, and spray modeling results of cryogen in the freezer supported simulation model of shrimp. Overall, numerical modeling results are consistent (≤5% variation) with experimental values.Practical ApplicationsThe cryogenic freezer is widely preferred to obtain a superior quality of frozen food products owing to minimal defects (cracking and break down), drip loss, and freezing time compared to traditional mechanical freezers. The inefficient utilization of cryogen and handling issues results in a higher cost of food products frozen with IQF technology. Thus, an insight into heat transfer phenomena in cryogenic freezers may lead to improvement in the design, efficient utilization of cryogen, reduction of freezing time, and improvement in overall product quality. In conclusion, these would aid in reducing the cost of the technology.

Strong Hydration Ability of Silk Fibroin Suppresses Formation and Recrystallization of Ice Crystals During Cryopreservation.

The cryopreservation (CP) of cell/tissue is indispensable in medical science. However, the formation of ice during cooling and ice recrystallization/growth in time of thawing present significant risk of cell/tissue damage upon analysis of CP process. Herein, the natural and biocompatible silk fibroin (SF) with regular hydrophobic and hydrophilic domains, were first employed as a cryoprotectant (CPA), to the CP of human bone-derived mesenchymal stem cells (hBMSCs), which has been routinely cyropreserved for cell-based therapies. Addtion of SF can regulate the formation of ice crystals during cooling process because of its strong hydration ability in the comparation to the cryopreservation medium (CM) without SF. Moreover, the devitrification-induced recrystallization/growth of ice during the thawing process is suppressed. Most importantly, the addition of 10 mg mL-1 SF can achieve 81.28% cell viability of cryopreserved hBMSCs as similar as those with the addition of 180 mg mL-1 Ficoll 70 (commercial CPA), and the functions of the cryopreserved hBMSCs are maintained as good as that of the fresh ones. This work is not only significant for meeting the ever-increasing demand of cell therapy, but also trailblazing for designing materials in controlling ice formation and growth during the CP of other cells and tissues.

Comparison of subcutaneous pocket with cryopreservation method for storing autologous bone flaps in developing surgical wound infection after Cranioplasty: A randomized clinical trial

BackgroundFollowing a decompressive craniectomy (DC), the harvested bone flap is stored for future cranioplasty. There are two different methods proposed for bone banking, namely subcutaneous pocketing (SP) in the abdominal wall and cryopreservation (CP) in a refrigerator. This study was designed to evaluate the risk of developing infection in each study group. MethodsIn this randomized clinical trial design, a total of 143 patients underwent a primary decompressive craniectomy. Thereafter, they were randomly allocated into two groups, as SP and CP, and they were then scheduled for a future cranioplasty. Next, 108 patients underwent cranioplasty using an autologous bone flap and then followed-up for 18 months. Some variables, including demographic data, indications for primary DC, rate of post-operative clinical infection, bacterial culture results, the interval between craniectomy and cranioplasty, post-operative hospitalization duration, new morbidities, mortality rate, bone flap resorption rate, and several possible associated risk factors, were also recorded. The obtained data were analyzed by an expert bio-statistician using proper bio-statistical methods. A P value < 0.05 was considered as statistically significant. ResultsFour patients in the cryopreservation group (n = 50) indicated post-operative bone flap infection (8%), which was statistically significant (P = 0.041). Accordingly, all of them were resulted as positive for Methicillin-Resistant-Staphylococcus aureus (MRSA). Using the subcutaneous pocket method, no post-operative infection was observed after cranioplasty. The overall postoperative infection rate was estimated as 4%. The mean of age in the post-operative infection group’s participants was 50.25 years old, and in the non-infected, it was 34.93 years old, which was also significant (P = 0.048). Bone flap resorption (BFR) rate was found to be higher by the use of CP method in comparison to SP technique (p = 0.0001). Of note, no other risk factor was found attributable to a higher BFR rate (p-values > 0.05). ConclusionsOlder age and cryopreservation method at higher storage temperature (-18C˚) may be associated with infection’s development after performing cranioplasty. BFR is more prevalent in the use of CP method rather than SP preservation technique.

Evaluation of toxicity of cryoprotectant to the sperm of mohashol fish, Tor tor (Hamilton) at various concentrations of the salt solution

Cryogenic gene banking is a prime necessity for conserving the genetic constitutes of vulnerable, endangered and critically endangered native and exotic fish species. Cryogenic freezing of fish gametes is the first step to develop such a gene bank. In the study, attempts have been taken to develop a cryogenic freezing protocol of spermatozoa of Mohashol, Tor tor as it is considered as a critically endangered fish species by IUCN. Juvenile and brood fish of Tor tor were collected from the Someshwari River of Netrokona district and domesticated in captive condition at Bangladesh Agricultural University campus. During breeding season, sperms were collected from hormone induced males by stripping. The milt was very sticky. The concentration of sperm was 4.47x1010 cells per ml and pH was 8.6±0.5. To evaluate the toxicity of cryoprotectant, sperm was incubated with DMSO and methanol at 5, 10 and 15% concentrations for a period of 5 to 55 min. The motility of sperm decreased with the increase of cryoprotectant concentration (5, 10 and 15%) and 10% DMSO with Alsever’s solution could be the best combination for cryopreservation of T. tor. sperm at 10 min (83.0±2.74).

Structure and Magnetic Properties of (Pr,Dy)–(Fe,Co)–B Alloys Prepared by Rapid and Slow Melt Cooling

Structure and Magnetic Properties of (Pr,Dy)–(Fe,Co)–B Alloys Prepared by Rapid and Slow Melt Cooling

Closure relations during the plateau emission of Swift GRBs and the fundamental plane

Abstract The Neil Gehrels Swift observatory observes gamma-ray burst (GRB) plateaus in X-rays. We test the reliability of the closure relations through the fireball model when dealing with GRB plateau emissions. We analyze 455 X-ray light curves collected by Swift from 2005 January until 2019 August for which the redshifts are either known or unknown using the phenomenological Willingale 2007 model. Using these fits, we analyze the emission mechanisms and astrophysical environments of these GRBs through the closure relations within the time interval of the plateau emission. Finally, we test the three-dimensional fundamental plane relation (Dainotti relation) which connects the prompt peak luminosity, the time at the end of the plateau (rest frame), and the luminosity at that time, for the GRBs with redshift, concerning groups determined by the closure relations. This allows us to check if the intrinsic scatter σint of any of these groups is reduced compared to previous literature. The most fulfilled environments for the electron spectral distribution, p &amp;gt; 2, are wind slow cooling (SC) and interstellar material (ISM) slow cooling for cases in which the parameter q, which indicates the flatness of the plateau emission and accounts for the energy injection, is 0 and 0.5, respectively, in cases with both known and unknown redshifts. We also find that for short GRBs all ISM environments with q = 0 have the smallest σint = 0.04 ± 0.15 in terms of the fundamental plane relation holding a probability of occurring by chance of p = 0.005. We have shown that the majority of GRBs presenting plateau emission fulfill the closure relations, including the energy injection, with a particular preference for the wind SC environment. The subsample of GRBs that fulfill the given relations can be used as possible standard candles and can suggest a way to reduce the intrinsic scatter of these studied relationships.

Effect of cryogenic freezing on the rheological and calorimetric properties of pasteurized liquid egg yolk

The egg yolk undergoes an irreversible gelation process when freezing to –6 °C or lower. In this experiment, liquid egg yolk (LEY) was frozen in liquid nitrogen and stored at –18 °C for 150 days. The measurement of pH and colour of LEY were performed. The examination of the rheological and calorimetric properties of samples was also carried out. The results indicated that the pH of LEY changed significantly during frozen storage, increasing from 6.37 ± 0.02 to 6.58 ± 0.03 over five months. The colour of the samples also showed a significant change compared to the fresh sample. The rheological properties of the LEY also changed significantly after 1 day of freezing and during frozen storage, with a clear increasing trend of the yield stress. The results of the calorimetric study showed that freezing and frozen storage did not affect the denaturation temperature, however, the denaturation enthalpy was reduced by about half after five months of frozen storage.

Influence of temperature-time crystallization conditions on PP + ZrO2 charge state and electret properties

PP + ZrO2 polymer nanocomposites obtained through different temperature-time modes of crystallization and exposed to electrothermopolarization were studied in this paper. Even though the preparation method of nanocomposite samples was the same, their lifetimes and surface charge density were different. It was investigated that nanocomposite obtained by slow-cooling (SC) conditions has high stability but low surface charge density. It was also revealed that the dependence of relaxation time of the electret state on the percentage content of filler has a nonmonotonic character. The change of the thickness of the interphase layer of nanocomposite depending on cooling rate is explained by the change of the supramolecular structure of the polymer and the interphase interaction among the components of the nanocomposite. It was considered that the change of the thickness of the interphase layer of the nanocomposite depending on the intensity of the electric field during electrothermopolarization due to the difference in charge accumulation during the polarization process.

Nitrogen vapor immersion: An accessible alternative for honey bee (Apis mellifera L.) semen cryopreservation

Semen cryopreservation is a valuable conservation tool and is often used in livestock species to accelerate artificial selection of desirable traits. Recently, semen cryopreservation has been successfully introduced to honey bees, bolstering trait selection for breeders and aiding conservation efforts for threatened bee populations. Current cryopreservation methods use slow-programmable freezing to achieve long-term storage of honey bee germplasm. However, the equipment necessary for this method is costly and time consuming to use, making it less accessible to breeders and researchers. We tested two cost and time efficient alternatives to slow-programmable freezing, vitrification and vapor immersion using two freezing devices, the CryoLock and microdialysis tube. Semen was preserved in either 20, 40, or 60% dimethyl sulfoxide (Me2SO). The post-thaw sperm viability (% living sperm) and subjective motility (0–5 scale) of these techniques were compared to those of slow-programmable frozen semen and non-frozen controls. Semen frozen in microdialysis tubes produced higher motility and sperm viability than semen frozen with the CryoLock device. The same trend was observed between vapor immersion and vitrification, with vapor immersion proving superior. Vapor immersed semen dialyzed with 20% Me2SO produced statistically similar sperm motility (4 ± 0.41) and viability (73.51% ± 5.56%) to slow-programmable freezing (4.25 ± 0.25, 80.61% ± 4.20%) and the non-frozen control (4.5 ± 0.28, 93.39% ± 0.90%). Optimization of the dialysis process and freezing rate may further increase the post-thaw sperm quality. Nonetheless, these results show promise for an effective replacement to slow-programmable freezing that maintains high sperm quality while increasing accessibility.

Slow Hot-Carrier Cooling Enabled by Uniformly Arranging Different-n-Value Nanoplates in Quasi-2D Perovskites through Long-Range Orbit-Orbit Interaction toward Enhancing Photovoltaic Actions.

This paper reports a slow hot-carriers cooling process enabled by uniformly arranging different-n-value nanoplates in quasi-2D perovskites (PEA2MAn-1PbnI3n+1). Here, the energetic carriers are slowly relaxing from 1.743 to 1.688 eV within the time window of 91.7 ps, shown in transient absorption (TA) dynamics. It verifies an unusual long-order electron-lattice coupling to slow down the relaxation of hot carriers, generating long-lived energetic carriers in quasi-2D perovskites. Furthermore, the long-range orbit-orbit interaction is established through orbital polarizations between excited carriers, identified by polarization-dependent photocurrent. This indicates that the long-range orbit-orbit interaction provides the necessary condition to enable the unusual long-order electron-lattice coupling, causing a slow hot-carrier cooling effect through the energy-momentum dispersion curvature within the crystalline lattice. Interestingly, with the slow hot-carrier cooling and long-range orbit-orbit interaction, the quasi-2D perovskite demonstrates superior carrier transport shown by high fill-factor values (>80%) with reduced photovoltaic loss in solar cells at all different carrier densities.

Microwave-vacuum-assisted drying of pretreated cranberries: Drying kinetics, bioactive compounds and antioxidant activity

This study focused on the effects of microwave-vacuum-assisted drying on the drying kinetics, bioactive compounds and antioxidant activity of whole cranberries subjected to different pretreatments, i.e. sonication, sonication combined with convective freezing, microwave-vacuum pretreatment, microwave-vacuum pretreatment combined with convective freezing, convective freezing and cryogenic freezing. Compared to hot air convective drying, microwave-vacuum-assisted drying shortened the drying time by 54%. The application of microwaves in the final stage of drying allowed to obtain drying rates 17 times higher than in the convective initial stage. Berries dried by microwave-vacuum-assisted drying were characterized by higher contents of polyphenols (from 22.14 ± 0.49 to 27.51 ± 0.56 mg GAE/g DM), flavonoids (from 2.65 ± 0.05 to 3.79 ± 0.11 mg CAE/g DM), anthocyanins (from 0.75 ± 0.10 to 2.22 ± 0.10 mg Cy-3G/g DM), antioxidant activity (from 33.03 ± 0.72 to 47.67 ± 0.39 mg TE/g DM) and a more desirable overall appearance than fruits after hot air convective drying. Among different initial treatments, freezing provided the best results in terms of drying time. Sonication gave the best results for the retention of bioactive components, antioxidant activity and the overall appearance of dried fruits.

Effects of carbohydrate content in seeds on the germination and viability after cryopreservation

This article is devoted to the study of the influence of cryopreservation on the preservation of sowing qualities of seeds of representatives of the genus Picea: P. asperata (Rough spruce) and P. pungens (Spiny spruce). As an alternative shock method of cryopreservation, the method of step-by-step 3-step temperature reduction was used 1 stage +4 °C, 2 stage –18 °C, 3 stage –196 °C liquid nitrogen. Additionally, the effect of 4 time intervals (1 hour, 24 hours, 72 hours and 168 hours) of step freezing on seed quality was investigated. To explain the results by photometry, the total carbohydrate content of the seeds is determined before the 3rd freezing step (cryo interaction). The analysis of the results of germination showed that the seeds of the studied species respond in different directions to the step cryo freezing. So, seeds of P. asperata germination in all tree experimental variants are higher on 4–32 % than in the control variant; and the maximum results are revealed in the variant with time intervals of 168 hours. For P. pungens seeds, the germination rates in experimental variants were on 18–22 % lower than in the control; and the largest germination rate of seeds among experimental variations are revealed in variant with interval 24 hours. The determination of the total carbohydrate content of the tested seeds at different cryogenic freezing intervals found that this indicator varied significantly depending on the time interval. The lowest values of total carbohydrates are found in variation with a time interval — 24 hours. The maximum total carbohydrate content is determined in a variation with a time interval — 1 hour. Correlation analysis between seed germination indices and total carbohydrate content established a high relationship between these indices. So, for P. asperata, the value of the Pearson coefficient was 0.86, and for P. pungens seeds — 0.91.

Cryogenic suspension design for a kilometer-scale gravitational-wave detector

We report the mirror suspension design for large-scale cryogenic gravitational wave telescope, KAGRA, during bKAGRA phase 1. Mirror thermal noise is one of the fundamental noises for room-temperature gravitational-wave detectors such as Advanced LIGO and Advanced Virgo. Thus, reduction of thermal noise is required for further improvement of their sensitivity. One effective approach for reducing thermal noise is to cool the mirrors. There are many technical challenges that must be overcome to cool the mirrors, such as cryocooler induced vibrations, thermal drift in suspensions, and reduction in duty cycling due to the increased number of potential failure mechanisms. Our mirror suspension has a black coating that makes radiative cooling more efficient. For conduction cooling, we developed ultra high purity aluminum heat links, which yield high thermal conductivity while keeping the spring constant sufficiently small. A unique inclination adjustment system, called moving mass, is used for aligning the mirror orientation in pitch. Photo-reflective displacement sensors, which have a large range, are installed for damping control on marionette recoil mass and intermediate recoil mass. Samarium cobalt magnets are used for coil-magnet actuators to prevent significant change of magnetism between room temperature and cryogenic temperature. In this paper, the design of our first cryogenic payload and its performance during bKAGRA phase 1 are discussed.

Preservation of fruit genetic resources in Germany

The preservation of fruit genetic resources has a long-lasting tradition in Germany. It dates back to the early decades of the 20th century. Ever since, a multitude of cultivars of different fruit crop species is preserved in federal and state governmental institutions as well as in communities and towns, non-governmental organizations, and by private individuals. The German Fruit Genebank has been established as a decentralized network with the aim to coordinate the preservation in the different germplasm collections in Germany to minimize the risk of losing cultivars of fruit species and therefore to maintain a part of the cultural heritage. Currently, the German Fruit Genebank is composed of six species-specific networks consisting of 48 different collections. In addition to the cultivar collections, the Fruit genebank of the Institute of Breeding Research on Fruit Crops, Dresden-Pillnitz includes collections of crop wild relatives of the fruit species important for fruit production in Central Europe. Special emphasis is given on the genera Malus and Fragaria representing 46 and 22 taxa respectively. These accessions are valued for their diverse alleles but also for their specific genotypes. Different cryopreservation protocols were elaborated. For Fragaria a protocol combining vitrification with cold acclimation and for Malus a protocol based on dormant winter buds can now be realistically used to build up a Cryo bank as a duplicate collection. Based on the results provided, a combination of the traditional ex situ conservation approach and cryopreservation approach has a great potential to improve conservation of fruit genetic resources contributing to the National Program for Genetic Resources of Agricultural and Horticultural Crops in Germany.

Slow Cooling and Fast Reinflation for Hot Jupiters

Abstract The unexpectedly large radii of hot Jupiters are a longstanding mystery whose solution will provide important insights into their interior physics. Many potential solutions have been suggested, which make diverse predictions about the details of inflation. In particular, although any valid model must allow for maintaining large planetary radii, only some allow for radii to increase with time. This reinflation process would potentially occur when the incident flux on the planet is increased. In this work, we examine the observed population of hot Jupiters to see if they grow as their parent stars brighten along the main sequence. We consider the relation between radius and other observables, including mass, incident flux, age, and fractional age (age over main-sequence lifetime), and show that main-sequence brightening is often sufficient to produce detectable reinflation. We further argue that these provide strong evidence for the relatively rapid reinflation of giant planets, and discuss the implications for proposed heating mechanisms. In our population analysis we also find evidence for a “delayed cooling effect,” wherein planets cool and contract far more slowly than expected. While not capable of explaining the observed radii alone, it may represent an important component of the effect. Finally, we identify a weak negative relationship between stellar metallicity and planet radius that is presumably the result of enhanced planetary bulk metallicity around metal-rich stars and has important implications for planet formation theory.

Cryogenic Bubbling Purification of Vegetable Oils from Impurities

The device, the principle of operation and the test results of the apparatus for cryogenic freezing of oils designed to isolate impurities characterized by a high-melting state under atmospheric environmental parameters are considered. It was found that in the mode of extracting wax substances and phospholipids with an average rate of bubbling nitrogen vapor through an oil layer w = 2.2 m/sec, the best results for extracting impurities of wax substances and phospholipid compounds with a high-melting structure are obtained. At a higher rate of bubbling nitrogen vapor through an oil layer (w = 2.5 m/sec or more), the freezing process is carried out with a high cooling rate, which adversely affects the nature of the high-quality agglomeration of high molecular weight impurities containing waxy and phospholipid fractions, and the final filtrate of frozen-out oil does not fully meet the requirements of the standard for physicochemical parameters.

Research on Risk Early Warning for the Cryogenic Freezing Rain and Snow Disaster

With the impact of global climate change on extreme weather and the rapid expansion of human activity range, the cryogenic freezing rain and snow disaster is becoming more frequent, bringing quite adverse effects on transportation, electric power and other industries, thus seriously affecting social and economic development and people’s daily life. Implementation of risk early warning is one of the most effective means to prevent the cryogenic freezing rain and snow disaster. This paper, taking Guizhou Province as an example, studies the early warning technology and method for the cryogenic freezing rain and snow disaster based on the demand for prevention of the cryogenic freezing rain and snow disaster, and considering meteorological factors, topography, social economy, power transportation and other factors. On this basis, the weight of risk factors is determined by subjective weighting method, the risk early warning model for the cryogenic freezing rain and snow disaster based on AHP is constructed, and the four-level risk early warning indexes are determined. Trial application is realized in Guizhou Province.