Freeze Injury Research Articles

American Burn Association Clinical Practice Guidelines on the Treatment of Severe Frostbite.

This Clinical Practice Guideline addresses severe frostbite treatment. We defined severe frostbite as atmospheric cooling that results in a perfusion deficit to the extremities. We limited our review to adults and excluded cold contact or rapid freeze injuries that resulted in isolated devitalized tissue. After developing population, intervention, comparator, outcomes (PICO) questions, a comprehensive literature search was conducted with the help of a professional medical librarian. Available literature was reviewed and systematically evaluated. Recommendations based on the available scientific evidence were formulated through consensus of a multidisciplinary committee. We conditionally recommend the use of rapid rewarming in a 38 to 42°C water bath and the use of thrombolytics for fewer amputations and/or a more distal level of amputation. We conditionally recommend the use of "early" administration of thrombolytics (≤12 hours from rewarming) compared to "later" administration of thrombolytics for fewer amputations and/or a more distal level of amputation. No recommendation could be formed on the use of vascular imaging studies to determine the use of and/or the time to initiate thrombolytic therapy. No recommendation could be formed on the use of intravenous thrombolytics compared to the use of intra-arterial thrombolytics on fewer amputations and/or a more distal level of amputation. No recommendation could be formed on the use of iloprost resulting in fewer amputations and/or more distal levels of amputation. No recommendation could be formed on the use of diagnostic imaging modalities for surgical planning on fewer amputations, a more distal level of amputation, or earlier timing of amputation.

Mechanistic insights into the improvement of yeast viability by adding short-clustered maltodextrin during long-term frozen storage

The formation and growth of ice crystals are widely acknowledged to cause damage to different substances and we found short-clustered maltodextrin (SCMD) could alleviate the quality deterioration of frozen dough in previous research. But how SCMD interacts with dough components such as yeast is poorly understood. Here, we analyze the ice-recrystallization-inhibition (IRI) activity of SCMD and provide mechanistic insights into the improvement of yeast viability by adding SCMD during long-term frozen storage. SCMD had a higher IRI activity compared with DE2 maltodextrin, trehalose and glycerin at the same dosage. Through untargeted metabolomics analysis, SCMD addition proved to be enhancing lipid metabolism, regulating amino acid metabolism and energy metabolism of yeast, making yeast cells possess more similarities to the positive control with minimal freeze injury. In contrast, no significant protective effects were observed with low-concentration trehalose and glycerin. Our reports reveal the cryoprotection mechanism of SCMD from the perspective of the cellular metabolism of yeast, providing the foothold for further exploration of SCMD as a safe and efficient cryoprotectant in different fields. • Short-clustered maltodextrin (SCMD) could change ice-crystal shapes. • SCMD had a higher ice-recrystallization-inhibition (IRI) activity than trehalose and glycerin at the same dosage. • SCMD addition could improve yeast viability and fermentation ability during long-term frozen storage. • SCMD addition enhanced lipid metabolism, regulated amino acid metabolism and energy metabolism of yeast. • SCMD cryoprotection mechanism was proposed.

Studying the thermal resistance of superhydrophobic carbon soot coatings for heat transfer management in cryogenic facilities

Except in microelectronics, food industry and power generation, the accurate temperature control is a fundamental precondition for the sustainable development of cryobiology too, where the partial cryodamage of frozen/thawed biospecies is still unavoidable. Setting favorable cooling and warming rates during cryopreservation helps to mitigate the detrimental intracellular icing and recrystallization, which is accomplishable using superhydrophobic carbon soot, whose thermal resistance however, has not been examined so far. This research introduces the first attempts of quantifying the thermal behavior of three basic categories soot distinguished by morphology, porosity, chemical composition and film thickness. The gradual cooling of six pairs of non-wettable soot coatings reveals that the diffusive thermal transport in their bulk is accompanied by phonon scattering governed predominantly by the pore arrangements, particle size, chemical bonding and interlayer spacing in the material. In turn, the soot incorporating ∼ 50–120 nm-sized nanoparticles, mesopores, moderate surface oxidation and thickness exceeding 50 µm exhibits the greatest capacity to delay the bulk heat conduction, opposite to the empirically established solid-liquid interfacial heat transfer mechanisms of the soot. Thus, merging specific physicochemical features within a single coating, via controlled flame synthesis and alcohol-fluorocarbon functionalization, would facilitate the fabrication of custom cryovials alleviating the two-factor freezing injury.

Five months under ice: biologging reveals behaviour patterns of overwintering freshwater turtles

Winter in temperate regions is characteristically the coldest period of the year. Species in these regions adapt to freezing temperatures with physiological or behavioural mechanisms to mitigate the threats of cold exposure. For aquatic species, taking refuge under the ice minimizes the risk of experiencing freeze injury. The northern map turtle ( Graptemys geographica (LeSueur, 1817)) is one species that overwinters under the ice of lakes and rivers. Here, we observed the behaviour of free-ranging map turtles at a known overwintering site throughout an entire winter using biologgers equipped with tri-axial acceleration, temperature, and depth sensors. We observed that map turtles maintain localized locomotor activity at the overwintering site continuously during the winter. The extent and patterns of locomotor activity and habitat use varied between adult females, adult males, and juvenile females. Adult females were observed at the shallowest depths, coldest temperatures and moved the least, whereas juvenile females were observed at the deepest depths, warmest temperatures and moved the most. All groups remained at temperatures near freezing (0.98–1.39 °C) and at average depths ranging from 1.34 to 1.7 m. These behavioural patterns are consistent with a strategy to survive the winter while remaining aerobic and likely reflect differences in physiological demands.

Manipulating flowering time of Protea ‘Pink Ice’ in Chile to prevent losses by bud freeze injury

Manipulating flowering time of <i>Protea</i> ‘Pink Ice’ in Chile to prevent losses by bud freeze injury

Effect of carbohydrate levels under autumn defoliation on cold tolerance during the subsequent flowering season in pear

Freezing injury to the flowers of deciduous fruit trees is being increasingly emphasized in the context of global warming due to low temperatures in spring. The annual accumulation of nutrients is affected by reserves in the organs during tree growth. In this study, changes in the total carbohydrate (TC), total starch (TS), and soluble solid (SS) content of shoots and changes in cold tolerance and free amino acid (FAA) and free sugar (FS) content of flowers were investigated to determine the effects of carbohydrate and FAA levels on the cold tolerance of pear flowers under autumn defoliation. The freezing injury rate of flowers increased with 50% and 100% defoliation at -2.8 °C. The TC, TS, and SS content in one-year-old shoots decreased after 100% defoliation; the TS content was reduced to one-third. Additionally, the FS and FAA content in flowers at the white-bud stage decreased due to defoliation. In particular, the sorbitol and glutamic acid content decreased after defoliation. These results suggest that maintaining carbohydrate levels is necessary to protect the flowers of pear and other deciduous fruit trees from low temperatures during the flowering season.

Comparison of transcriptome and metabolome analysis revealed differences in cold resistant metabolic pathways in different apple cultivars under low temperature stress

Freezing injury in winter is an important abiotic stress that seriously affects plant growth and development. Deciduous fruit trees resist freezing injury by inducing dormancy. However, different cultivars of the same species have different cold resistance strategies. Little is known about the molecular mechanism of apple trees in response to freezing injury during winter dormancy. Therefore, in this study, 1-year-old branches of the cold-resistant cultivar ‘Hanfu’ (HF) and the cold-sensitive cultivar ‘Changfuji No. 2’ (CF) were used to explore their cold resistance through physiological, biochemical, transcriptomics, and metabolomics analyses. Combining physiological and biochemical data, we found that HF had a stronger osmotic regulation ability and antioxidant enzyme activity than CF, as well as stronger cold resistance. The functional enrichment analysis showed that both cultivars were significantly enriched in pathways related to signal transduction, hormone regulation, and sugar metabolism under freezing stress. In addition, the differentially expressed genes (DEGs) encoding galactinol synthase, raffinose synthase, and stachyose synthetase in raffinose family oligosaccharides (RFOs) metabolic pathways were upregulated in HF, and raffinose and stachyose were accumulated, while their contents in CF were lower. HF accumulated 4-aminobutyric acid, spermidine, and ascorbic acid to scavenge reactive oxygen species (ROS). While the contents of oxidized glutathione, vitamin C, glutathione, and spermidine in CF decreased under freezing stress, consequently, the ability to scavenge ROS was low. Furthermore, the transcription factors apetala 2/ethylene responsive factor (AP2/ERF) and WRKY were strongly induced under freezing stress. In summary, the difference in key metabolic components of HF and CF under freezing stress is the major factor affecting their difference in cold resistance. The obtained results deepen our understanding of the cold resistance mechanism in apple trees in response to freezing injury during dormancy.

Betula alnoides Admixed with Castanopsis hystrix or Cunninghamia lanceolata from Two Reforestation Case Studies in Southeast China

Background: There was no literature showed superior provenance or clone of B. alnoides selected for the development of southern Fujian, as well as no suitable reforestation mixed pattern for B. alnoides developed for preventing the trunk pests effectively. It is significant to select an optimal reforestation pattern for B. alnoides to be expanded in southern Fujian. Methods: The tissue-cultured seedlings of Betula alnoides were introduced to south-east China for reforestation mixed pattern tests. B. alnoides was admixed with Castanopsis hystrix with five patterns at Wanshiqing Area and admixed with Cunninghamia lanceolata with four patterns at Beijing Area. A sample plot of 20 m × 30 m was set in each experimental treatment and each tree was investigated in the sample plot, including tree height (m), DBH (cm), pests and diseases and freeze injury. Result: The effects of the pure forest were better than that of the cluster mixed forest in tree height. The cluster mixed pattern was not beneficial to the tree height growth of B. alnoides and DBH growth of C. lanceolata in early stage. The average annual growth of B. alnoides in tree height, DBH and individual volume achieved 2.2-2.5 m, 2.8-3.0 cm and 0.0061-0.0074 m3, respectively.

Pediatric Environmental Cold Injuries.

Cold weather injuries are relevant concerns for children during winter sports and outdoor activities. To mitigate the risk of cold injury in this high-risk population, providers can educate parents on proper outdoor attire as well as the added risks of wind and water exposure. There are 2 types of environmental cold injuries: freezing injuries and nonfreezing injuries. Frostbite is a freezing injury from direct contact with cold air or surfaces. The extent of injury depends on the depth to which the freezing extends. Treatment involves rewarming the frozen tissue with warm water baths and considering analgesia. Hypothermia is a nonfreezing cold injury, and it can occur even when ambient temperatures are above freezing. When there is a decrease in the body's core temperature, hypothermia progresses from mild to severe symptoms. Treatment of hypothermia is threefold but is also dependent on the core body temperature, as colder core temperatures will require more aggressive warming techniques. Hypothermia treatment involves passive protection from further heat loss (ie, removing wet clothing), which helps the body to warm itself. Treatment also involves active external rewarming wherein a heat source, such as a heated blanket, is used to increase body temperature. Active internal rewarming is the delivery of heat inside the patient's body, such as warmed intravenous fluids.

Preparation of Poly(vinyl Alcohol) Microparticles for Freeze Protection of Sensitive Fruit Crops.

Poly(vinyl alcohol) (PVA) displays ice recrystallization inhibition (IRI) properties as many antifreeze proteins found in cold tolerant organisms. The molecular architecture and composition (molecular weight and distribution of pendant OH and acetate groups) have been studied to improve the antifreezing properties of PVA, suggesting that the molecular architecture of PVA plays an important role in IRI activity. The present work deals with the preparation of PVA microparticles using an alkaline treatment. The effect of PVA molecular weight on the morphology and antifreezeing properties of PVA microparticles was investigated. The antifreezeing property of PVA microparticles on the susceptibility of flower bud tissues to freeze damage was also evaluated. The alkaline treatment of an aqueous PVA solution produced stable polymer chain aggregates with spherical shapes. The average size of the PVA microparticles increased significantly with the increasing molecular weight of the PVA macromolecule precursor. The PVA microparticles inhibited the growth of ice crystals and blocked ice growth at concentrations as low as 0.01 % w/v. The effect of impeding ice crystal growth by preventing the joining of adjacent ice crystals is attributed to the larger size of the PVA particles adsorbed on the ice surface compared to the aggregated PVA macromolecules in saline solution. The thermal hysteresis activity of PVA macromolecules and microparticles was not detected by differential scanning calorimetry analysis. The PVA microparticles reduced the incidence of freeze injuries in flower bud tissues by 55% and their application, considering the low toxicity of PVA, has a high potential for freeze protection in fruit crops.

Effects of chill unit accumulation and temperature on woody plant deacclimation kinetics.

Woody perennials in temperate climates develop cold hardiness in the fall (acclimation) and lose cold hardiness in the spring (deacclimation) to survive freezing winter temperatures. Two main factors known to regulate deacclimation responses are dormancy status and temperature. However, the progression of deacclimation responses throughout the dormant period and across a range of temperatures is not well described. More detailed descriptions of dormancy status and temperature, as factors regulating deacclimation, are necessary to understand the timing and magnitude of freeze injury risks for woody perennials in temperate climates. In this study, we modeled deacclimation responses in cold‐climate interspecific hybrid grapevine cultivars throughout the dormant period by integrating chill accumulation and temperature through the concept of deacclimation potential. We evaluated deacclimation and budbreak under multiple temperature treatments and chill unit accumulation levels using differential thermal analysis (DTA) and bud forcing assays. Deacclimation responses increased continuously following logistic trends for both increasing chill unit accumulation and increasing temperature. There are optimal temperatures where deacclimation rates increased but changes in deacclimation rates diminished below and above these temperatures. The cumulative chill unit range where deacclimation potential increased overlapped with the transition from endo‐ to ecodormancy. Therefore, deacclimation potential could provide a quantitative method for describing dormancy transitions that do not rely on the visual evaluation of budbreak. This information provides a more detailed understanding of when and how deacclimation contributes to increased risks by freezing injury. In addition, our descriptions could inform improvements to models predicting cold hardiness, dormancy transitions, and spring phenology.

Influence of estradiol deficiency on the acute inflammatory response following a traumatic skeletal muscle injury

Abstract Estradiol (E2) influences the inflammatory response. Research has shown that skeletal muscle chemokine mRNA expression and neutrophil infiltration after a traumatic freeze injury are blunted in ovariectomized mice treated with placebo compared to E2-treated mice. How E2 deficiency alters the acute muscle inflammatory response is unclear with potential mechanisms including alterations in the number of circulating leukocytes, leukocyte chemotaxis, and/or muscle chemokine expression. To investigate these possibilities, female C57BL/6J mice underwent a sham or ovariectomy (OVX) surgery, 21–28 d later tibialis anterior (TA) muscles were freeze injured. TA muscles and blood were collected 24 h post injury. Total white blood cell (149%) and monocytes (427%) were elevated in OVX compared to Sham mice but there was no difference in the neutrophil counts (p≥0.64). To determine if E2 deficiency impacts leukocyte chemotaxis, isolated leukocytes from bone marrow of non-injured Sham or OVX mice were placed in a transwell migration assay. OVX leukocytes had greater chemotaxis towards CXCL1 (37%), CXCL2 (43%), and CXCL5 (27%) than Sham. To examine if E2 deficiency alters muscle CXCL1 and CXCL5 protein content contributing to chemotaxis, ELISA assays were performed. Surprisingly, muscle CXCL1 and CXCL5 contents were similar between OVX and Sham. Collectively, mice lacking E2 have relatively high blood leukocytes and chemotaxis suggesting a greater acute inflammatory response which appears not to be driven by changes in muscle chemokine expression. Additional studies need to consider possible negative regulators of the acute inflammatory response in OVX muscle. Supported by DAL and GW (R01AG031743 &amp; R01AG062899), and SLM (T32AR007612)

Detection of pear freezing injury by non-destructive X-ray scanning technology

During storage and long-distance refrigerated transport, low temperatures may lead to invisible freezing injury, which lowers the overall fruit quality and shortens storage time. As a result, nondestructive evaluation of freezing injury is necessary to evaluate the quality of fruit. The freezing injury of pear Xinli No.7 was experimentally investigated using X-ray technology and scanning electron microscope (SEM). It was found that the gray value of the freezing region in the X-ray image of pear was higher than that of the healthy region, based on which the freezing injury could be distinguished nondestructively. Besides, the area of the freezing region increased linearly with the decrease of the freezing temperature and the gray value increased monotonically when the freezing time increases. Based on the observation of the micro-structure of the freezing pear using an electron microscope, the variation of the gray value is due to the changes of the cavities formed by ice crystals, increasing with the degree of freezing injury. This study explored the X-ray images to determine the severity of pear freezing injury and revealed the mechanism of X-ray variation caused by freezing injury, which is conducive to determining the freezing time and temperature for the purpose of preservation, reducing storage cost and optimizing long-distance refrigerated transportation.

Regulation of phenylpropanoid metabolism during moderate freezing and post-freezing recovery in Dendrobium officinale

ABSTRACT Freezing injury is a major environmental limiting factor affecting plant yield and geographical distribution. Little is known about the regulation of phenylpropanoid metabolism during freezing (FT) and post-freezing recovery (FR). Dendrobium officinale is a valuable medicinal plant and hypersensitive to low temperature, especially freezing in winter. Here, we used metabolomics and transcriptomics analyses to reveal the regulation of of phenylpropanoid metabolism during FT and FR in D. officinale. Most anthocyanin and flavonol significantly increased during FR, including quercetin 3-O-glucoside (Q3G) and cyanidin 3-O-sophoroside (C3S) increased 104.6-fold and 66.8-fold in FR vs. CK. Transcriptomics analyses revealed the expression levels of flavonoid 3′- hydroxylase (F3`H) and flavonol synthase (FLS), which were related to an increase in quercetin derivatives. Six phytohormone-related GO terms were enriched during FT and FR. Four genes were significantly affected by FT and FR, including MYB97, MYB39, fructosyltransferase, and zinc finger transcript factor. Four GA response-related genes, 2-oxoglutarate-dependent dioxygenases, were specially induced during freezing stress. Moreover, jasmonic acid (JA) and salicylic acid (SA) were significantly increased during FT, and only SA decreased during FR. This study provided understanding of phenylpropanoid metabolism under freezing stress and will be useful for enhancing freezing tolerance via molecular breeding in D. officinale.

基于主成分-聚类分析的不同水分冬小麦晚霜冻害评价

<p id="C3">To investigate the effect of low temperature at jointing stage on wheat physiological metabolism under different water conditions, a comprehensive physiological index is constructed to accurately evaluate the degree of freezing injury, which is of great significance to agricultural loss reduction, efficiency increase and macro management. Irrigation (W1) and no irrigation (W0) treatments were carried out one week before low temperature treatment using the weak-spring Yanzhan 4110 and Lankao 198, semi-winter Zhengmai 366 and Fengdecun 21 as the experimental materials. At the female and male ear differentiation stages, potted wheat was moved to the low temperature simulation room for low temperature treatment with six levels of normal (CK), -2℃ (T1), -4℃ (T2), -6℃ (T3), -8℃ (T4), and -10℃ (T5), respectively. The physiological indexes and fluorescence parameters were measured on the second day after treatment, and wheat yield was harvested at maturity stage. The results revealed that different varieties, water and low temperature stress, and their interactions had significant effects on wheat physiological indexes and fluorescence parameters at jointing stage. With the aggravation of low temperature stress, leaf water content, chlorophyll a content and fluorescence parameters <italic>q</italic>_p, <italic>F</italic>_v/<italic>F</italic>_m, and <italic>F</italic>_v/<italic>F</italic>_o showed the continuous downward trends, the contents of soluble protein, proline, soluble sugar, and SOD activity first increased and then decreased, but the content of MDA demonstrated the opposite trend. Irrigation treatment alleviated the influence of low temperature stress on plant physiological metabolism, and the effect of low temperature on semi-winter varieties was relatively lower. Four independent comprehensive indexes were transformed by the principal component analysis, which reflected 88.55% of the original information, and the physiological comprehensive index of freezing injury (FICEI) was constructed. The depth of color in heat map indicated the darker the color, the greater the performance degree of indicators. According to the FIPCI value, the freezing injury was divided into five levels, which was consistent with the yield loss rate. Especially under T3 treatment, the yield loss rate of each variety reduced by 30.4%-44.0% under no irrigation, reduced by 21.0%-29.2% under irrigation treatment. Under the same irrigation condition, yield loss rate of different varieties was LK198&gt;YZ4110&gt;ZM366&gt;FDC21, and the yield loss rate of semi-winter varieties was lower than that of weak spring varieties. According to the results of heat map clustering and the yield of each treatment, the yield loss rate was less than 10% for CK and T1, 10%-30% for W0T2, W1T2 and W1T3, 30%-50% for W0T3 and W1T4, more than 50% for W0T4, W0T5 and W1T5. Irrigating before low temperature was conducive to alleviating the damage caused by low temperature stress and reducing the yield loss. Physiological comprehensive freezing injury index and model constructed by principal component-cluster analysis can accurately evaluate the degree of wheat late frost damage, and provide scientific basis for yield recovery and decision-making management after disaster.

Blueberry bud freeze damage detection using optical sensors: Identification of spectral features through hyperspectral imagery

BACKGROUND: Highbush blueberry (Vaccinium corymbosum), the species primarily grown in the state of Washington, U.S., is relatively cold hardy. However, low temperatures in winter and early spring can still cause freeze damage to the buds. OBJECTIVE: This study explored hyperspectral imaging (HSI) for detecting freeze induced bud damage. Blueberry buds (c.v. Duke) were collected over two seasons and tested in the laboratory to detect damage at four typical phenological stages. METHODS: The HSI data was acquired via line scan HSI system with spectral wavelength ranging from 517 to 1729 nm for buds grouped into either normal or injured mortalities. The successive projection algorithm was employed for pertinent feature wavelength selection. Analysis of variance and linear regression were then applied for evaluating sensitivity of feature wavelengths. RESULTS: Overall, five salient wavelengths (706, 723, 872, 1384, and 1591 nm) were selected to detect bud freeze injury. A quadratic discriminant analysis method-based analysis verified reliability of these five wavelengths in bud damage detection with overall accuracy in the ranges of 64 to 82%for the test datasets of each stage in two seasons. CONCLUSIONS: This study indicated potential of optical sensing to identify the injured buds using five salient wavelengths.

A method for obtaining field wheat freezing injury phenotype based on RGB camera and software control

BackgroundLow temperature freezing stress has adverse effects on wheat seedling growth and final yield. The traditional method to evaluate the wheat injury caused by the freezing stress is by visual observations, which is time-consuming and laborious. Therefore, a more efficient and accurate method for freezing damage identification is urgently needed.ResultsA high-throughput phenotyping system was developed in this paper, namely, RGB freezing injury system, to effectively and efficiently quantify the wheat freezing injury in the field environments. The system is able to automatically collect, processing, and analyze the wheat images collected using a mobile phenotype cabin in the field conditions. A data management system was also developed to store and manage the original images and the calculated phenotypic data in the system. In this experiment, a total of 128 wheat varieties were planted, three nitrogen concentrations were applied and two biological and technical replicates were performed. And wheat canopy images were collected at the seedling pulling stage and three image features were extracted for each wheat samples, including ExG, ExR and ExV. We compared different test parameters and found that the coverage had a greater impact on freezing injury. Therefore, we preliminarily divided four grades of freezing injury according to the test results to evaluate the freezing injury of different varieties of wheat at the seedling stage.ConclusionsThe automatic phenotypic analysis method of freezing injury provides an alternative solution for high-throughput freezing damage analysis of field crops and it can be used to quantify freezing stress and has guiding significance for accelerating the selection of wheat excellent frost resistance genotypes.

Hyperbaric Oxygen Therapy with Iloprost Improves Digit Salvage in Severe Frostbite Compared to Iloprost Alone

Background and Objectives: Frostbite is a freezing injury that can lead to amputation. Current treatments include tissue rewarming followed by thrombolytic or vasodilators. Hyperbaric oxygen (HBO) therapy might decrease the rate of amputation by increasing cellular oxygen availability to the damaged tissues. The SOS-Frostbite study was implemented in a cross-border program among the hyperbaric centers of Geneva, Lyon, and the Mont-Blanc hospitals. The objective was to assess the efficacy of HBO + iloprost among patients with severe frostbite. Materials and Methods: We conducted a multicenter prospective single-arm study from 2013 to 2019. All patients received early HBO in addition to standard care with iloprost. Outcomes were compared to a historical cohort in which all patients received iloprost alone between 2000 and 2012. Inclusion criteria were stage 3 or 4 frostbite and initiation of medical care <72 h from frostbite injury. Outcomes were the number of preserved segments and the rate of amputated segments. Results: Thirty patients from the historical cohort were eligible and satisfied the inclusion criteria, and 28 patients were prospectively included. The number of preserved segments per patient was significantly higher in the prospective cohort (mean 13 ± SD, 10) compared to the historical group (6 ± 5, p = 0.006); the odds ratio was significantly higher by 45-fold (95%CI: 6-335, p < 0.001) in the prospective cohort compared to the historical cohort after adjustment for age and delay between signs of freezing and treatment start. Conclusions: This study demonstrates that the combination of HBO and iloprost was associated with higher benefit in patients with severe frostbite. The number of preserved segments was two-fold higher in the prospective cohort compared to the historical group (mean of 13 preserved segments vs. 6), and the reduction of amputation was greater in patients treated by HBO + iloprost compared with the iloprost only.

A Review of Methods and Techniques for Detecting Frost on Plant Surfaces

Severe frost usually has adverse impacts on agricultural production, resulting in crop freeze injury, poor crop yield, and crop quality reduction. Timely and accurate detection of frost plays an important role in cold damage warnings, prevention, and control. Current frost detection methods mostly use physical properties such as light, electricity, and heat, or the judge and quantify using environmental factors such as temperature and wind speed. However, it is difficult to detect and accurately identify the frosting phenomenon in real time during field trials because of the complex environment, different plant types, and interference by many factors during observation. To provide an overview of the analytical tools for scientists, researchers, and product developers, a review and comparative analysis of the available literature on frost mechanisms, correlations, and characteristics are presented in this study. First, the mechanisms of the frost formation process, frost level, and the significance of detection, are introduced. Then, the methods and techniques used to measure frost on plant surfaces are synthetically classified and further compared. Moreover, the key points and difficulties are summarized and discussed. Finally, some constructive methods of frost detection are proposed to improve the frost detection process.

Physiological and biochemical responses of strawberry crown and leaf tissues to freezing stress

BackgroundIn northern Iran and other cold regions, winter freezing injury and resultant yield instability are major limitations to strawberry production. However, there is scarcity of information on the physiological and biochemical responses of strawberry cultivars to freezing stress. This study aimed to investigate the physiological and biochemical responses of strawberry cultivars (Tennessee Beauty, Blakemore, Kurdistan, Queen Elisa, Chandler, Krasnyy Bereg, and Yalova) to different freezing temperature treatments (− 5, − 10, − 15, − 20, and − 25 °C) under controlled conditions.ResultsAll measured physiological and biochemical features were significantly affected by the interaction effect between low temperatures and cultivars. Tennessee Beauty showed the highest RWC at − 25 °C. The highest Fv/Fm was observed in Queen Elisa. Krasnyy Bereg had the least freezing injury (FI) in crown and leaf, while Yalova and Chandler showed the highest crown and leaf FI, respectively. At − 20 to − 25 °C, the highest carbohydrates contents of crown and leaf were noted in Blakemore and Krasnyy Bereg cultivars, respectively. The Yalova showed the highest protein content in both crown and leaf tissues at − 25 °C. The Tennessee Beauty and Blackmore cultivars showed the highest proline in crowns and leaves at − 15 °C, respectively. The highest ThioBarbituric Acid Reactive Substances (TBARS) contents in the crown and leaf were observed in Kurdistan and Queen Elisa, respectively. Queen Elisa and Krasnyy Bereg cultivars showed SOD and POD peaks in the crown at − 15 °C, respectively.ConclusionFreezing stress was characterized by decreased Fv/Fm and RWC, and increased FI, TBARS, total carbohydrates, total proteins, proline content, and antioxidant enzyme activity. The extent of changes in above mentioned traits was cultivar dependent. FI and TBARS were the best traits among destructive parameters for evaluating freezing tolerance. Moreover, maximum quantum yield of PSII (Fv/Fm index), as non-destructive parameters, showed a significant efficiency in rapid assessment for screening of freezing tolerant strawberry cultivars. The cultivars Krasnyy Bereg, Queen Elisa, and Kurdistan were the most tolerant cultivars to freezing stress. These cultivars can be used as parents in breeding programs to develop new freezing tolerant cultivars.