High Freezing Resistance Research Articles

Relationships between freezing resistance and biochemicals in grapevine buds and canes: Different soluble carbohydrates accumulate in several cultivars during cold acclimation

Owing to recent warming trends during the growing season, wine grapevine (Vitis vinifera) production has increased in subarctic areas such as Hokkaido. However, high freezing resistance remains essential for grapevines due to the severe winter temperatures in these regions. Here, we investigated the seasonal variation in freezing resistance, as well as the water, soluble carbohydrate, proline, and total phenolic content (TPC) in the buds and canes of two V. vinifera cultivars and a Vitis riparia hybrid, Maeve. We found that freezing resistance in the buds and canes increased from fall to winter, with Maeve exhibiting higher freezing resistance than the V. vinifera cultivars during both seasons. Maeve experienced a faster rate of deacclimation, leading to comparable spring freezing resistance among all cultivars. The water content in the buds and canes of all three cultivars decreased during the fall, with Maeve showing an earlier reduction compared to the others. Most soluble carbohydrates increased in winter and decreased in spring. Notably, Maeve, which had higher winter freezing resistance, accumulated more sucrose in its buds and a higher concentration of soluble carbohydrates, particularly monosaccharides, in its canes compared to the other two cultivars. Proline and TPC levels were not linked to freezing resistance. Grapevine buds and canes appeared to accumulate soluble carbohydrates, especially monosaccharides, during winter, while reducing water content in fall to enhance freezing resistance. This study suggests that grapevine cultivars in Hokkaido may utilize different types of soluble carbohydrates to improve the freezing resistance of their buds and canes.

Efficient and cold-tolerant moisture-enabled power generator combining ionic diode and ionic hydrogel.

The ionic diode structure has become one of the attractive structures in the field of moisture-based power generation. However, existing devices still suffer from poor moisture trapping, low surface charge, and inefficient ion separation, resulting in low output power. Moreover, water freezes at low temperatures (<0 °C), limiting the ionic diode structure to generate electricity in cold environments. In this paper, a moisture-enabled power generator has been designed and fabricated, which assembles a negatively charged ionic hydrogel film and a positively charged anodized aluminum oxide (AAO) film to construct a heterojunction. The hydrogel polymer network is modified with a large number of sulfonate groups that dissociate to provide nanoscale pores with high surface charge to improve the rectification ratio. And the lithium chloride (LiCl) salt with high hydration ability is added to the hydrogel as a moisture-trapping and anti-freezing component. Usually salt ions reduce the Debye length, so that the ion transport is finally not controlled by the electric double layer (EDL) and the rectification fails. Interestingly, due to the natural affinity of the hydrogel polymer network for LiCl, LiCl is locked on the hydrogel side and does not easily enter the AAO pores to change the distribution of EDL within the nanochannel. As a result, the device rectification ratio is almost independent of the amount of LiCl addition, demonstrating an excellent balance of high output power and high freeze resistance. Ultimately, the device exhibits excellent power generation performance in the -20 °C to 60 °C temperature range and 15% to 93% RH humidity range. Typically, under high humidity (93% RH) at room temperature (25 °C), it provides an open-circuit voltage of 1.25 V and a short-circuit current of 300 μA cm-2, with an on-load output power of up to 71.35 μW cm-2. Under medium humidity (50% RH) at low temperature (-20 °C), it provides an open-circuit voltage of 1.11 V and a short-circuit current of 15 μA cm-2.

High water-retaining, antifreeze micro-supercapacitor without encapsulation for all-weather

The development of portable electronics puts forward new challenges for miniaturization of energy storage devices to match them. Micro-supercapacitors (MSCs) with significant advantages have attracted increasing attention recently. MSCs are usually encapsulated in practical use to ensure a stable performance due to uncertainty of electrolyte in open system, even quasi-solid electrolyte such as hydrogels electrolyte which gradually dries once exposed to air for a few hours or freezes in cold environment. Herein, we demonstrate a high water-retaining and antifreeze micro-supercapacitor (AW-MSC) without encapsulation adaptable to all-weather for the first time. Ion conductive hydrogel through copolymerizing sulfobetaine methacrylate and sodium acrylate acts as electrolyte after soaking by lithium chloride aqueous solution. The resultant polyelectrolyte exhibits an outstanding water holding capacity even in simulated dry desert climate (lower than 20% relative humidity) and high freeze resistance in cold environment (under −20 °C). Consequently, the assembled AW-MSC without encapsulation exhibits the capacitance retention above 85.0% after 32 days in either severe cold, drought, or high heat environments, superior to those MSCs-based on hydrogels reported previously. In various harsh simulation scenarios, the AW-MSC connected in series can steadily power an electronic watch for a long time.

Cathepsin L involved in the freezing resistance of murine normal hatching embryos and dormant embryos

The cryopreservation of mammalian embryos is an important technology in embryo engineering. The discovery and application of the embryo's own high freezing resistance factors are the main methods to improve the utilization of mammalian embryos in cryopreservation. Cathepsin L gene expression in the frozen and thawed dormant embryos displayed a significant difference from those normal hatched ones. The aim of the present study was to dig out the potential role of Cathepsin L in anti-freezing capacity of murine blastocysts by investigating the location and expression of Cathepsin L in frozen and thawed both activated and dormant hatching blastocysts. Different concentrations of Cathepsin L recombinant protein and E-64d were then respectively added into the embryo cryoprotectant and pre-cryo culture medium. Our results found that down-regulation of Cathepsin L improves the freezing resistance of murine normal hatching embryos by reducing apoptosis. Cathepsin L inhibitors can be used to improve the efficiency of cryopreservation and recovery of blastocysts in vitro. Our study provides a theoretical basis for the further development and application of Cathepsin L.

Mechanism of Overwintering in Trees.

Boreal trees possess very high freezing resistance, which is induced by short-day length and low temperatures, in order to survive severe subzero temperatures in winter. During autumn, cooperation of photoreceptors and circadian clock system perceiving photoperiod shortening results in growth cessation, dormancy development, and first induction of freezing resistance. The freezing resistance is further enhanced by subsequent low temperature during seasonal cold acclimation with concomitant changes in various morphological and physiological features including accumulation of sugars and late embryogenesis abundant proteins. The mechanism of adaptation to freezing temperatures differs depending on the type of tissue in boreal trees. For example, bark, cambium, and leaf cells tolerate freezing-induced dehydration by extracellular freezing, whereas xylem parenchyma cells avoid intracellular freezing by deep supercooling. In addition, dormant buds in some trees respond by extraorgan freezing. Boreal trees have evolved overwintering mechanisms such as dormancy and high freezing resistance in order to survive freezing temperatures in winter.

Cryopreservation of very low numbers of spermatozoa from male patients undergoing infertility treatment using agarose capsules

This study tried to cryopreserve low numbers of spermatozoa from men undergoing infertility treatments by inserting into agarose capsules. The capsules were transferred into a drop of cryoprotectant solution and injected 3-4 motile spermatozoa that were selected by the swim-up method by conventional intracytoplasmic sperm injection. These capsules were put on a Cryotop® and frozen in liquid nitrogen vapor, and then submerged into liquid nitrogen and subsequently thawed and recovered. The motile spermatozoa in the capsules were counted. Eventually, we cryopreserved 2142 motile spermatozoa in 702 agarose capsules from 26 male patients and 1356 (63%) spermatozoa maintained their motility after thawing. The spermatozoa motility rates after thawing (MRAT) ranged from 20.0% (5/25) to 95.1% (58/61) among patients. The median MRAT was 68.3% (interquartile range 46.1-75.7). The total number of motile spermatozoa collected by swim-up method strongly correlated with MRAT (r=0.746). It was possible to cryopreserve spermatozoa from male patients undergoing infertility treatment using agarose capsules. However, there were wide differences in MRAT among patients. It seems the spermatozoa from semen where there were many motile spermatozoa may have higher freezing resistance. Further studies using this method in cryptozoospermic semen, testicular and epididymal spermatozoa are required.

Summer Freezing Resistance: A Critical Filter for Plant Community Assemblies in Mediterranean High Mountains.

Assessing freezing community response and whether freezing resistance is related to other functional traits is essential for understanding alpine community assemblages, particularly in Mediterranean environments where plants are exposed to freezing temperatures and summer droughts. Thus, we characterized the leaf freezing resistance of 42 plant species in 38 plots at Sierra de Guadarrama (Spain) by measuring their ice nucleation temperature, freezing point (FP), and low-temperature damage (LT50), as well as determining their freezing resistance mechanisms (i.e., tolerance or avoidance). The community response to freezing was estimated for each plot as community weighted means (CWMs) and functional diversity (FD), and we assessed their relative importance with altitude. We established the relationships between freezing resistance, growth forms, and four key plant functional traits (i.e., plant height, specific leaf area, leaf dry matter content (LDMC), and seed mass). There was a wide range of freezing resistance responses and more than in other alpine habitats. At the community level, the CWMs of FP and LT50 responded negatively to altitude, whereas the FD of both traits increased with altitude. The proportion of freezing-tolerant species also increased with altitude. The ranges of FP and LT50 varied among growth forms, and only leaf dry matter content was negatively correlated with freezing-resistance traits. Summer freezing events represent important abiotic filters for assemblies of Mediterranean high mountain communities, as suggested by the CWMs. However, a concomitant summer drought constraint may also explain the high freezing resistance of species that thrive in these areas and the lower FD of freezing resistance traits at lower altitudes. Leaves with high dry matter contents may maintain turgor at lower water potential and enhance drought tolerance in parallel to freezing resistance. This adaptation to drought seems to be a general prerequisite for plants found in xeric mountains.

Fast acclimation of freezing resistance suggests no influence of winter minimum temperature on the range limit of European beech

Low temperature extremes drive species distribution at a global scale. Here, we assessed the acclimation potential of freezing resistance in European beech (Fagus sylvaticaL.) during winter. We specifically asked (i) how do beech populations growing in contrasting climates differ in their maximum freezing resistance, (ii) do differences result from genetic differentiation or phenotypic plasticity to preceding temperatures and (iii) is beech at risk of freezing damage in winter across its distribution range. We investigated the genetic and environmental components of freezing resistance in buds of adult beech trees from three different populations along a natural large temperature gradient in north-western Switzerland, including the site holding the cold temperature record in Switzerland. Freezing resistance of leaf primordia in buds varied significantly among populations, with LT50values (lethal temperature for 50% of samples) ranging from -25 to -40 °C, correlating with midwinter temperatures of the site of origin. Cambial meristems and the pith of shoots showed high freezing resistance in all three populations, with only a trend to lower freezing resistance at the warmer site. After hardening samples at -6 °C for 5 days, freezing resistance of leaf primordia increased in all provenances by up to 4.5 K. After additional hardening at -15 °C for 3 days, all leaf primordia were freezing resistant to -40 °C. We demonstrate that freezing resistance ofF. sylvaticahas a high ability to acclimate to temperature changes in winter, whereas the genetic differentiation of freezing resistance among populations seems negligible over this small geographic scale but large climatic gradient. In contrast to the assumption made in most of the species distribution models, we suggest that absolute minimum temperature in winter is unlikely to shape the cold range limit of beech. We conclude that the rapid acclimation of freezing resistance to winter temperatures allows beech to track changing climatic conditions, especially during unusually warm winters interrupted by very cold weather.

The Effect of Additives Including Metakaolin on the Freeze Resistance of Concrete

With the help of research studies on the freeze resistance of concrete with complex additives containing metakaolin it is found that its optimum amount with microsilica and plasticizing agents can provide concrete with high freeze resistance of F11000 and more. The use of metakaolin – superplasticizing admixture contributes to a slight increase of freeze resistance of concrete only due to the consolidation of its structure as a result of increasing the degree of hydration of main minerals of concrete С3S and β-С2S under the influence of metakaolin. It is proved that the optimal amount of metakaolin together with superplasticizing admixture helps to form the phase composition of cement stone from highly basic hydrosilicates and stable hydroaluminates. The use of overdosed metakaolin leads to appearance of a great number of metastable hydroaluminates in the cement stone which makes it inefficient for the production of freeze-proof concrete.

HSP90 expression correlation with the freezing resistance of bull sperm

To date, there has been little improvement in cryopreservation of bull sperm due to lack of understanding of the freezing mechanisms. Therefore, this study set out to investigate expression levels of fertility-associated proteins in bull sperm, and in particular the relationship between the 90 kDa heat-shock protein (HSP90) and the sperm characteristics after freezing-thawing. Semen was collected from eight Holstein bulls by artificial vagina. Characteristics of these fresh semen, including sperm motility, morphology, viability and concentration, were evaluated. Sperm quality was also assessed after freezing-thawing. Eight ejaculates were divided into two groups based on freezing resistance and sperm motility. Sperm proteins were extracted and sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) analysis and western blotting were performed. SDS-PAGE results showed that there was substantial diversity in 90 kDa proteins in the frozen-thawed sperm and HSP90 was confirmed as one of the 90 kDa proteins by western blot. This study indicated that HSP90 expression correlated positively with sperm quality. The amount of expressed 90 kDa proteins in the high freezing resistance (HFR) group was significantly higher than that in the low freezing resistance (LFR) group (P < 0.05). Thus, higher expression of HSP90 could probably lead to the higher motility and freezing resistance of sperm found after freezing-thawing. Therefore, we concluded that level of HSP90 expression could be used to predict reliably and simply the freezing resistance of bull sperm.

Study on High Freeze-Resistance of Concrete

In this paper, the freeze-resistance of concrete is studied for the special requirements of the engineering. Through the analysis of the damage mechanism of concrete’s freezing and thawing; researching the effect on freeze-resistance of concrete when to be mixed into active mineral ingredients additive and admixture; proposing the right mix proportioning to fit the request of project; making a good result by testing the property of mixture and the mechnical property of concrete as well as its freeze-resistance.

Freezing resistance varies within the growing season and with elevation in high‐Andean species of central Chile

Predicted increases in the length of the growing season as a result of climate change may more frequently expose high-elevation plants to severe frosts. Understanding the ability of these species to resist frosts during the growing season is essential for predicting how species may respond to changes in temperature regimes. Here, we assessed the freezing resistance of 24 species from the central Chilean Andes by determining their low temperature damage (LT(50)), ice nucleation temperature (NT), freezing point (FP) and freezing resistance mechanism (i.e. avoidance or tolerance). The Andean species were found to resist frosts from -8.2 to -19.5 degrees C during the growing season, and freezing tolerance was the most common resistance mechanism. Freezing resistance (LT(50)) varied within the growing season, decreasing towards the end of this period in most of the studied species. However, the FP showed the opposite trend. LT(50) increased with elevation, whilst FP was lower in plants from lower elevations, especially late in the growing season. Andean species have the potential to withstand severe freezing conditions during the growing season, and the aridity of this high-elevation environment seems to play an important role in determining this high freezing resistance.

Fluorosiloxane sealants for aviation industry

Properties of sealants based on fluorosiloxane oligomers are considered. It is shown that polysibxanes containing the γ-trifluoropropyl radical can be applied in practice as the base for sealants. It is established that the flexibility of the siloxane chain is responsible for high freeze resistance, while large values of the energy of polar-Si-O-bond allow us to obtain materials with high thermal stability. Mechanical and technological properties of fluorosiloxane sealants are reported, and their advantages relative to materials on the basis of organofluoric rubbers are shown. The domains of the applicability of sealants for surface and interjoint sealing are discussed. It is shown that sealants based on fluorosiloxane oligomers are characterized by adequate stability to prolonged action of different fuels and are widely used in the aircraft construction.

Synthesis and study of the properties of aromatic fluorine-containing copolyamides

Low-temperature polycondensation in the amide-salt system N-methyl-2-pyrrolidone+LiCl has been used to synthesize mixed polyamides based on terephthalic acid and mixtures of m- or p-phemylenediamine with β-hydroperfluoroethyoxy-2,4-phenylenediamine. The concentration of the fluorinated diamine was varied from 0 to 100 mole %. The thermal and hydrolytic stability, the solubility of the polyamides and the properties of films were studied. It was established that the mixed polyamides began to lose weight in the temperature region 653–663 K. The introduction of the fluorinated substituent into the polyamide macrochain increases the hydrolytic stability in an acidic medium and the polymers' solubility is also raised. The unoriented films have a high freeze-resistance and satisfactory strength properties.

Freezing Resistance of Alpine Plants

During the growing season alpine plants on Mt. Kurodake (1,984 m) in the Taisetsu mountain range in Hokkaido, Japan, survived freezing to only —5° to —7°C. Even after exposure to 0° and —3°C for 2 weeks, the resistance to freezing of these plants increased only slightly. During the winter, however, most alpine plants studied survived freezing at temperatures below —30°. Salix pauciflora, Diapensia lapponica, mosses, an lichens resisted freezing down to —70°C. They also retained viability after immersion in liquid nitrogen following prefreezing at —30°C. Furthermore, there did not appear to be an essential difference in the hardening effect between willows growing in high mountains and in low altitudes in Hookaido. Alpine plants may be characterized by their dwarf form, short growth period, and high freezing resistance of subterranean stems, crowns, and roots.