Thawing Stage Research Articles

Influence of Soil Salinization on Active Layer Thickness of Frozen Soil

The climate of the Qinghai–Tibet Plateau is distinct. Given the large temperature difference between day and night, drought in perennial years, low rainfall and large evaporation volume, the frozen soil in some areas of the Qinghai–Tibet Plateau will occur in soil salt. The presence of salt in frozen soil salt changes the water thermal characteristics of the frozen soil, which will affect the changes in its activity layer. In this paper, the Beiluhe area of the Qinghai–Tibet Plateau was selected as the research object, and the numerical calculation model of water, heat and salt of salinised frozen soil was established. Considering the influence of salt crystallisation and salt on the freezing temperature of the active layer, the effects of different salt concentrations, water contents and salt type on the temperature of frozen soil and the thickness of the active layer were compared and analysed. Therefore, the salt of soil degenerates frozen soil under the action of sodium chloride and sodium sulphate, and the presence of sodium chloride and sodium sulphate is not conducive to the stability of frozen soil for many years. During soil salinisation, the content of sodium chloride in frozen soil increases; the temperature of permafrost initially decreases and then increases; the initial freezing time of the active layer is postponed in the freezing and cooling stages, the time when the water in the active layer with a salt concentration of 0.2–0.8% was delayed by 21, 32, 54 and 65 days; the temperature of the active layer decreases, which is the opposite in the thawing and heating stages, and the thickness of the active layer increases with the increase in salt concentration. During soil salinisation, the content of sodium sulphate in frozen soil increases; the freezing temperature of the active layer initially decreases and then increases and finally decreases, which is contrary to the temperature of the active layer in the warm season. The thickness of the active layer initially increases (with a maximum increase in 0.82 m) and then decreases and finally increases with the increase in salt concentration. The content of sodium sulphate in frozen soil has little effect on the initial freezing time of the active layer. High water content is conducive to the stability of permafrost. When the content of sodium chloride in frozen soil is constant, the water content increases; the temperature change of frozen soil is smaller; the temperature of the active layer in the warm season is lower; the thickness of the active layer is smaller, and the frozen soil tends to be more stable. When the content of sodium sulphate is constant, the increase in water content generally reduces the warm-season temperature of the active layer and the thickness of the active layer (−6 m the temperature of 30% and 40% water content in −6 m is 0.17 °C and 0.24 °C lower than that of 20% water content). However, analysis of the thickness of the active layer of the frozen soil containing sodium sulphate must combine the influence of water content and freezing temperature.

Effects of freeze-thaw cycles on nutrient removal from bioretention cells

There have been numerous summaries of the runoff purification characteristics of bioretention cells in warm climates. However, little has been done on the effects of freeze-thaw cycles (FTCs) that frequently occur in cold regions on bioretention cell performance. Three experimental columns were constructed to simulate the operation of the bioretention cell under the FTCs. The effects of FTCs on the nutrient removal efficiency of different filling bioretention cells were analyzed. The results showed that the ammonia nitrogen (NH4+-N) concentration in the effluent of the wood chip bioretention cell under the T3 conditions (WBCF) (2.35 mg/L) was significantly higher than that of the wood chip bioretention cell operating at room temperature (WBCR) (0.62 mg/L). The effluent NH4+-N concentration of aluminum sludge bioretention cell (ABCF) (0.096 mg/L) under the FTCs was lower than that of WBCF (0.91 mg/L). Under the T3 condition, the effluent nitrate nitrogen (NO3−-N) and total nitrogen (TN) concentrations of WBCF (5.33 mg/L and 8.86 mg/L) were higher than those of WBCR (5 mg/L and 6.11 mg/L) at room temperature. Under FTCs conditions, both WBCF and ABCF had high NO3−-N removal efficiency (up to 85.87% and 24.75%) at the initial stage of thawing of the filler, and the efficiency gradually decreased with the thawing of the filler. With the increase of FTCs, the NO3−-N removal efficiency of WBCF gradually decreased (always higher than 13.6%), while the removal efficiency of ABCF fluctuated wildly (the removal efficiency was primarily negative). The total phosphorus (TP) concentration in the effluent of WBCF (0.11 mg/L) under the T3 conditions was lower than that of WBCR (0.02 mg/L) at room temperature, and the TP concentration of ABCF (0.021 mg/L) in the effluent under the FTCs was slightly lower than that of WBCF (0.031 mg/L). The FTCs have a more significant impact on removing nitrogen pollutants in runoff, but have little effect on phosphorus. Compared with aluminum sludge, wood chips are more suitable for efficient removal of nitrogen pollutants in runoff under the FTCs. The experimental conclusions can provide a reference for the construction of bioretention cells in cold regions.

Effects of biochar addition on nitrous oxide emission during soil freeze-thaw cycles.

Biochar applied to soil can reduce nitrous oxide (N2O) emissions produced by freeze-thaw processes. Nonetheless, how biochar modification affects N2O emissions during freeze-thaw cycles is not completely clear. In our research, during freeze-thaw cycles, microcosm experiments were conducted to investigate the effects of maize straw biochar (MB) or rice straw biochar (RB) addition on soil N2O emissions under different water conditions. The N2O emissions peaked at the initial stage of thawing in all the soils, and the total N2O emissions were considerably greater in the flooded soils than in the nonflooded soils. Compared with the soils without biochar addition, RB and MB amendments inhibited N2O emissions by 69 and 67%, respectively. Moreover, after biochar addition, the abundance of AOB amoA genes decreased by 9-13%. Biochar addition significantly decreased the content of microbial biomass nitrogen (MBN) in flooded soil during thawing, which was significantly correlated with N2O emissions and nitrification and denitrification communities. The PLS-PM further revealed that biochar can inhibit the production and emission of soil N2O by reducing soil MBN during soil thawing. In addition, soil moisture directly significantly affects N2O emissions and indirectly affects N2O emissions through its influence on soil physicochemical properties. Our results revealed the important function of biochar in decreasing the emission of N2O in flooded soil during freeze-thaw cycles.

High‐resolution stable isotopic signals of ground ice indicate freeze–thaw history in permafrost on the northeastern Qinghai–Tibet Plateau

AbstractUnderstanding the mechanism of formation of ground ice and the freeze–thaw history of permafrost is essential when assessing the future of permafrost in a changing climate. High‐resolution ground ice records, integrating stable isotopes (δ18O, d‐excess, and δ13C), hydrochemistry (EC and pH) data, and cryostratigraphy at a depth of 4.8 m from two contrasting permafrost profiles (P‐1, P‐2) in the Source Area of the Yellow River (SAYR) on the northeastern Qinghai–Tibet Plateau (QTP), were investigated. The results suggested significant depth variations in the stable isotopes and hydrochemistry of the ground ice. The near‐surface ground ice (NSGI) and deep‐layer ground ice (DLGI) were characterized in terms of variations in stable isotopes and known modern active layer data. By synthesizing the measured δ18O and the modeled isotopic fractionation processes during freezing, we suggest that both the NSGI and DLGI in P‐1 were mainly formed by the segregation mechanism during permafrost aggradation. The NSGI in P‐2, however, exhibited quick freezing origins compared with the predominant ice segregation processes for the DLGI. By combining the evolution of various stable isotopes and hydrochemistry with 14C age data, four historical freeze–thaw stages were identified. Specifically, one thawing–refreezing stage (2.8–2.2 m), one freezing aggradation stage (2.2–1.6 m), and two permafrost aggradation–degradation cycle stages (4.8–2.8 m; 1.6–0.7 m) were differentiated, which emphasize the importance of climate‐induced freeze–thaw transitions and differing permafrost aggradation processes on ground ice formation and resultant isotope hydrochemical behaviors. This study is the first to use high‐resolution data in ground ice to interpret the freeze–thaw history of permafrost in the SAYR. These findings are important for further understanding of past permafrost evolution and projected future permafrost degradation trends on the QTP, and provide an alternative method to explore permafrost history.

Effect of Freeze-Thaw on Mechanical Properties of Loess with Different Moisture Content in Yili, Xinjiang

Various geological disasters such as collapses, landslides, and mudslides occur frequently in Yili, Xinjiang. The loess in this area provides a basis for the occurrence of landslides and other disasters. At the same time, Yili Valley is typically a seasonally frozen soil region. The freeze–thaw cycle is an essential disaster-inducing factor. However, scholars have lain a research emphasis on the material source of the Yili Loess, while lacking a systematic investigation of the degradation mechanism of the soil’s physical and mechanical properties under the freeze–thaw action. Therefore, it is prudent to investigate the changes in mechanical properties of loess in this region under the freeze–thaw cycle. In this study, focusing on a typical loess landslide in Yili, some in situ soil samples were collected to conduct related physical and mechanical tests. According to the maximum dry density and optimum moisture content of the loess in the region, four different groups of soil samples with varying moisture contents were prepared and subjected to different freeze–thaw cycles. The changes of apparent individual characteristics under freeze–thaw cycles were observed, and a consolidated undrained (CU) shear test was carried out to obtain the changes of shear strength indices of loess samples with varying moisture contents under freeze–thaw cycles. The results showed the obvious development of characteristics during freeze–thaw cycles, with the growth of many frost and ice crystals. At the freezing stage, the growth of ice crystals led to hexagonal peeling bodies on the surface layer. At the thawing stage, a rapidly melting network ice crystal pattern imposed a thermal thawing disturbance on the surface rock soil. After multiple freeze–thaw cycles, the soil’s peak strength dropped significantly and the internal friction angle changed slightly, but the cohesion was adversely affected, with frequent fluctuations. The present study enhances the research level of loess’s mechanical and strength properties under freeze–thaw cycles and provides a theoretical foundation for preventing loess landslides in this region.

Motion characteristics and plasma integrity evaluation of Murrah buffalo semen

Buffalo semen collected from Murrah bull were cryopreserved and evaluated for different motility parameter, kinematics and plasma membrane integrity. Buffalo bulls were maintained uniform standard management and nutritional practices. Semen was collected regularly twice a week semen collection schedule from four (04) Murrah bull. Collected semen was immediately transported to laboratory and evaluated for different macroscopic parameter (color, volume and thickness). Fresh semen was then diluted with saline solution and evaluated for sperm concentration, motility, sperm kinematics and morphology. Semen samples that fill all the standard were selected for freezing and diluted with Tris-egg yolk citrate diluter. Diluted semen was equilibrated, cryopreserved and finally evaluated for post thaw sperm quality. Different motility parameter (total, progressive, static and slow motility) varied significantly (p<0.01) irrespective of different freezing stages. Significantly higher progressive sperm motility and viability of buffalo spermatozoa were observed at fresh semen whereas lower progressive sperm motility and viability was found at post thaw stage. Total and progressive motility reduced by 2.5 and 2.12% following equilibration, whereas following cryopreservation, total and progressive motility reduced by 35.7 and 28.51% and static motility increases accordingly (35.4%). Significantly higher plasma membrane integrity of sperm was observed at fresh semen followed by pre freeze and post thaw semen. Following freezing, integrity of plasma membrane reduces at the rate of 10.81% and 26.7% at pre freezing and post thaw stages. Significantly higher average path velocity (VAP), straight line velocity (VSL), curvilinear velocity (VCL), straightness (STR), amplitude of lateral head displacement (ALH) and beat cross frequency (BCF) were found for fresh semen followed by pre-freeze and post-thaw semen. Frozen buffalo semen with higher progressive motility and motion characteristics may be produced if motility losses can be reduced during freezing stage as this stage results higher motility losses. Asian Australas. J. Biosci. Biotechnol. 2022, 7(2), 75-81

Mapping substrate use across a permafrost thaw gradient

Permafrost thaw in northern peatlands is likely to create a positive feedback to climate change, as microbes transform soil carbon (C) into carbon dioxide (CO2) or methane (CH4). While the microbiome's encoded C-processing potential changes with thaw, the impact on substrate utilization and gas emissions is less well characterized. We therefore examined microbial C-cycling dynamics from a partially thawed Sphagnum-dominated bog to a fully thawed sedge-dominated fen in Stordalen Mire (68.35°N, 19.05°E), Sweden. We profiled C substrate utilization diversity and extent by Biolog Ecoplates™, then tested substrate-specific hypotheses by targeted additions (of glucose, the short chain fatty acids (SCFAs) acetate and butyrate, and the organic acids galacturonic acid and p-hydroxybenzoic acid, all at field-relevant concentrations) under anaerobic conditions at 15 °C. In parallel we characterized microbiomes (via 16S rRNA amplicon sequencing and quantitative polymerase chain reaction) and C gas emissions. The fen exhibited a higher substrate use diversity and faster rate of overall substrate utilization than in the bog, based on Biolog Ecoplate™ incubations. Simple glucose additions (akin to a positive control) to peat microcosms fueled fermentation as expected (reflected in enriched fermenter lineages, their inferred metabolisms, and CO2 production), but also showed potential priming of anaerobic phenol degradation in the bog. Addition of SCFAs to bog and fen produced the least change in lineages and in CO2, and modest suppression of CH4 primarily in the fen, attributed to inhibition. Addition of both organic acids greatly increased the CO2:CH4 ratio in the deep peats but had distinct individual gas dynamics and impacts on microbiota. Both organic acids appeared to act as both C source and as a microbial inhibitor, with galacturonic acid also likely playing a role in electron transfer or acceptance. Collectively, these results support the importance of aboveground-belowground linkages - and in particular the role of Sphagnum spp.- in supplying substrates and inhibitors that drive microbiome assembly and C processing in these dynamically changing systems. In addition, they highlight an important temporal dynamic: responses on the short time scale of incubations (which would reflect transition conditions in the field) differ from those evident at the longer scales of habitat transition, in ways consequential to C gas emissions. In the short term, substrate addition response reflected microbiome legacy (e.g., bog communities were slower to process C and better tolerated inhibitors than fen communities) but led to little overall increase in C gas production (and a high skew to CO2). At the longer time scale of bog and fen thaw stages (which are used to represent these systems in models) the concomitant shifts in plants, hydrology and microbiota attenuate microbiome legacy impacts on substrate processing and C gas emissions over time. As habitat transition areas expand under accelerating change, we hypothesize an increased role of microbiome legacy in the landscape overall, leading to a lag in the increase of CH4 emissions expected from fen expansion.

Optimal Terms of Surgical Treatment of Adhesive Capsulitis (Retrospective Study)

Summary. Relevance. Surgical treatment of adhesive capsulitis is infrequent, as the doctor is convinced that this pathology has a staged course and the 'thawing stage' is inevitable in 12-24 months. Unfortunately, this is not always the case.
 Objective: to determine the optimal timing for surgical treatment of adhesive capsulitis.
 Materials and Methods. From 2015 to 2019, we performed 175 arthroscopic surgeries in patients with adhesive capsulitis of the shoulder joint, of which 59 (33.7%) patients were diagnosed with type 2 diabetes. The age of patients ranged from 40 to 70 years. The average age was 55.9±17.2 years. All patients were divided into 2 groups (group 1 – adhesive capsulitis and a history of diabetes, group 2 – adhesive capsulitis). In our study, we retrospectively assessed the function of the shoulder joint on the Constant Shoulder Score and VAS scales before surgery and 12 months after surgery.
 Results. The surgery performed within 100 days in patients with adhesive capsulitis and diabetes mellitus (group 1) when evaluated on the Constant Shoulder Score demonstrates worse results than the surgery performed at a later date (r=0.6; p<0.05); similar results were obtained on the VAS scale (r=0.62; p<0.05). The surgery performed within 100 days in patients with adhesive capsulitis (group 2) shows worse results on the Constant Shoulder Score than the surgery performed at a later date (r=0.775; p<0.05); similar results were obtained on the VAS scale (r=0.57; p<0.05). There is a tendency of less effective results of treatment on the Constant Shoulder Score and the VAS scale in patients of group 2 when performing surgery more than 350 days after the onset of the disease.
 Conclusions. Despite a number of conservative methods of treatment of adhesive capsulitis, timely surgery allows to obtain good treatment results. The optimal period for surgical intervention in adhesive capsulitis ranges from 100 to 350 days from the onset of the disease.

Thawing plateau time indicating the duration of phase transition from ice to water is the strongest predictor for long-term durable pulmonary vein isolation after cryoablation for atrial fibrillation

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): Helse Vest, Norway (LBS), and the Research Council of Norway (SYC). Background Cryoballoon ablation is an important method for pulmonary vein (PV) isolation in treatment of atrial fibrillation (AF). Previous studies have shown that thawing time, but not freezing time or temperature, impacts PV reconnection during long-term follow-up. However, it is unknown whether the entire or only part of the thawing stage plays a critical role. Purposes This study aimed to clarify the relationship between the durability of PV isolation and the time of phase transition from ice to water indicated by thawing plateau (TP) time during a cryoballoon ablation. Methods In this retrospective study, 241 PVs from 71 patients who underwent a repeat AF ablation 526 (IQR: 412, 675) days after a cryoballoon ablation were analyzed. The predictive value of procedural parameters for the durability of PV isolation were evaluated. Definitions of different phases of the temperature-time curve are shown in Figure 1. TP Time is defined as the time from 0 to 10°C inside the balloon in the thawing period (the plateau on the curve). Results Reconnection was observed in 101 (41.9%) PVs of 53 patients (74.6%). Durable PV isolation was associated with significantly longer TP Time compared with PV reconnection (26.0 vs. 11.0 s, P<0.001). The proportion of durable PV isolations increased with TP Time in a dose-proportional manner (Figure 2). The cut point for PV reconnection was TP Time <15 s with a positive predictive value of 82.1% (sensitivity=63.4%, specificity=90.0%) while for durable PV isolation the cut point was TP Time >25 s with a positive predictive value of 84.6% (sensitivity=55.0%, specificity=86.1%). After the analysis of multivariable logistic regression, location of PV (P<0.01), and TP Time (P<0.05) were shown as independent predictors for durable PV isolation. None of nadir temperature, initial cooling time, effective freezing time, initial thawing time, or late warming time was independent predictor. Accumulated TP Time for all PVs showed a positive linear correlation with the plasma level of troponin T (ρ=0.624, P<0.01). Conclusions TP Time is an independent predictor for the durability of PV isolation, and it presents in a dose-proportional manner. TP Time <15 s predicts long-term reconnection while TP Time >25 s predicts durable PV isolation.

Modification of the vacuum-steam thawing method of meat by using the initial stage of sublimation dehydration

Vacuum-steam thawing is one of the methods used for defrosting food, realized in the atmosphere of water vapour under the conditions of reduced pressure. The water vapour formed in vacuum with the temperature of 20 °C fills the defrosting chamber and condenses on the surface of the defrosted product. The condensated steam has the role of thermal energy carried enabling product thawing. The study presents a modification of this method, introducing an additional stage of sublimation-dehydration vacuum steam thawing (SRVST). The study was carried out for different variants of initial sublimation degree (in the range from 0 to 15%) of a slice of pork loin (m. longissimus lumborum) assessing the final effect of the process of vacuum-steam thawing. Thawing kinetics was determined with the SRVST method, degree of sample defrosting and level of their rehydration. Based on the results it was demonstrated that the use of 12% sublimation dehydration of a meat sample enables its complete defrosting (reaching the temperature not exceeding the cryoscopic temperature).

Development of a laboratory method for determination of the quality and freshness of frozen poultry meat

Traceability of poultry meat quality imported into Kazakhstan is an urgent task. To increase their benefits, some suppliers resort to falsification – they misrepresent thawed meat for chilled raw materials or carry out several cycles of freezing-thawing meat. The objective of these studies is to develop reliable methods for determining the quality and freshness of frozen natural semi-finished poultry meat, including the number of cycles of freezing and thawing meat. Dressed broiler chickens developed by the manufacturer from the Russian Federation using gas and electric stunning of poultry were selected as the research objects. A synchronous analysis device was used for thermal analysis in the heating-cooling process. Histomorphological studies were carried out on a microscope with an eyepiece magnification of x7. Histological examination revealed alterations in the structure of re-frozen and thawing lean tissue. The differential scanning calorimetry (DSC) analysis showed that the specific heat of thawing broiler fillets stunned by electric current during the first thawing is 218.8 J/g, at the second 209.5 J/g, and the third 201.4 J/g, and the specific heat of thawing broiler fillets stunned by gas during the first thawing is 176.5 J/g, at the second 171.9 J/g, and the third 162.6 J/g. Samples of broiler fillets stunned by electric current lost about 2.5% at each thawing stage, and with gas stunning 3% of moisture. The obtained results and research methods can be used to establish the falsification of the thermal state of broiler chicken meat by its undeclared freezing-thawing.

Ultrasonography-guided hydrodissection using platelet-rich plasma or corticosteroid in adhesive capsulitis of the shoulder: A comparative study

Background: Adhesive capsulitis is a condition that presents with pain and progressive limitation of both active and passive shoulder movements. It can be primary or secondary, the latter includes causes such as rotator cuff tear, cardiovascular disease, and diabetes mellitus. The American Shoulder and Elbow Surgeons defines that adhesive capsulitis is a condition of uncertain ethology characterized by a significant restriction of both active and passive shoulder motions that occur in the absence of known intrinsic shoulder disorder. Commonly described as: Stage 1 – Freezing stage, with pain and stiffness lasting around 9 months. Stage 2 – Frozen stage, with persistent stiffness lasting 4–12 months. Stage 3 – Thawing stage, with spontaneous recovery lasting 12–42 months. Ultrasonography (USG)-guided hydrodissection is used for adhesive capsulitis of the shoulder due to its cost-effectiveness and acceptance among patients. As adhesive capsulitis is postulated as an i nflammatory and fibrotic disease, easy treatment with intra-articular corticosteroids (CSs) injection may reduce synovitis, limit the development of capsular fibrosis, and alter the natural history of disease. CS injections are effective for shorter duration, but newer agents such as platelet-rich plasma (PRP) are more effective with no serious side effects. Materials and Methods: In this study, 40 patients were taken of adhesive capsulitis of the shoulder and were divided randomly into two groups. One group received injection PRP and the other group received injection CS. The outcome was recorded. Results: There was a statistically significant reduction in numeric rating scale pain scores in both the groups over a time period of 6 weeks, but the PRP injection was observed to be better in reducing the pain scores when compared to the CS injection after the 6th week (P = 0.037). Initially, the CS injection performed better in the 1st week due to anti-inflammatory action. By the 3rd week, both the injections showed a similar effect. However, at the end of the study period (6 weeks), there was a better reduction in the Shoulder Pain and Disability Index (SPADI) pain scores (P = 0.0057) and SPADI disability scores (P = 0.029) of the group PRP. Conclusion: We concluded that USG-guided hydrodissection with PRP is more effective therapy than CS in terms of reduction of pain and improvement in shoulder function in the treatment of adhesive capsulitis of shoulder.

Cryoprotectant With A Mitochondrial Derived Peptide, Humanin, Improves Post-Thaw Quality Of Buffalo Spermatozoa

BACKGROUND:Semen cryopreservation results in deleterious effects on spermatozoa, including lipid peroxidation and a reduction in the total antioxidant components of seminal plasma. The ultimate outcome of these changes is a reduction in post-thaw semen quality. A mitochondrial derived peptide, humanin, a potent cytoprotective and antioxidant agent was used in the present study.OBJECTIVE:To evaluate the efficacy of a mitochondrial-derived peptide, humanin to improve the post-thaw quality of buffalo spermatozoa.MATERIALS AND METHODS:A total of 18 ejaculates from three Murrah buffalo bulls (n=6 each) were collected. Each ejaculate was divided into four aliquots. The first aliquot was diluted with standard EYTG dilutor (Group I, control), whereas the other three aliquots were diluted with EYTG supplemented with 2 μM (Group II), 5 μM (Group III) and 10 μM humanin (Group IV), respectively. Semen was evaluated for physico-morphological and functional attributes such as progressive motility, viability, abnormality, acrosome integrity, plasmamembrane integrity of fresh samples, pre-freeze and post-thaw stages. Oxidative stress parameters [lipid peroxidation (LPO) and total antioxidant capacity (TAC)] were also measured at the pre-freeze and post-thaw stages.RESULTS:Humanin s upplementation resulted in significantly higher (p≤0.05) post- thaw motility in all treatment groups and, higher (p≤0.05) viability in Groups III and IV in comparison to the control at the post-thaw stage. Spermatozoa with intact acrosome and plasma membran e were higher (p≤0.05) in Groups III and IV as compared to Group s I and II. The LPO levels at the post- thaw stage were found to be lower (p≤0.05) in all treatment groups versus the control group, whereas, higher (p≤0.05) TAC value s were recorded in Groups III and IV in comparison to the control and Group II.CONCLUSION:Humanin supplementation in the extender improved the freezabilty of buffalo spermatozoa.

Kuwait: Az Zour delayed again

The litterbags with different mesh sizes (0.125, 1.000 and 3.000 mm) were placed on the forest floor in October 2010, and collected after each of the three stages in the freeze-thaw season (OF: the onset of freezing stage; DF: the deeply frozen stage; and TS: the thawing stage). Over the whole freeze-thaw period, 14.01% ± 1.26, 20.64% ± 1.61 and 30.89% ± 0.70 of N released from fir litter in the litterbags with 0.125, 1.000 and 3.000 mm, respectively. The contributions of meso- and macro-fauna to N releases were 21.45% ± 3.80 and 33.18% ± 5.39, respectively. Macro-fauna contributed more to N releases than meso-fauna regardless of decomposition stages in the freeze-thaw period. Compared with other stages in the freeze-thaw period, higher contributions of both macro- and meso-fauna were observed at DF stage, and the lower contributions at TS stage. The results suggested that soil fauna have a great contribution to N releases during litter decomposition in the freeze-thaw period, but the contribution was significantly affected by temperature dynamics and the body size of soil fauna.

Improving Ground Heat Flux Estimation: Considering the Effect of Freeze/Thaw Process on the Seasonally Frozen Ground

AbstractAn inadequate understanding of the changes in water and heat of the soil is likely a potential reason for the nonclosure of the surface energy balance. During the freeze/thaw period, the large volumetric heat capacity of ice and the latent heat of soil ice phase change had a specific influence on the estimation of ground heat flux (G0). However, the effects of the freeze/thaw process on G0 estimation were not well quantified using field observations. The improvements of G0 estimation by adding the soil ice heat storage (Δsice) and the latent heat of soil ice phase change (ΔsLH) were evaluated during the freeze/thaw period at two sites (Madoi and Maqu) on the eastern Tibetan Plateau. During the freeze/thaw period, both Δsice and ΔsLH had important influences on the reasonable determination of G0. Adding ΔsLH increased G0 at the daytime peak by 34.4 W/m2 (Madoi) and 9.3 W/m2 (Maqu). During the completely frozen stage, the contributions of Δsice to G0 ice + LH (adding both Δsice and ΔsLH) were higher than those during other freeze/thaw stages at both sites, and ΔsLH also made a significant contribution to G0 ice + LH. Therefore, the daily freeze/thaw cycles cannot be ignored during the completely frozen stage in the estimation of G0. The G0 ice + LH approach improved the G0 estimation more than G0 ice (adding Δsice) approach during the freezing and thawing stages. The improvements of G0 estimations increased the energy closure status and reduced the daily average of imbalance.

Thermolability of factor VIII in donor fresh frozen blood plasma

A criterion of the quality of fresh frozen blood plasma (FFP) is the activity of clotting factor VIII (FVIII).Aim — to identify technological barriers in the study of FVIII thermolability and to describe the requirements for experiments, providing new knowledge about the thermolability of this factor.Basic information. An analysis of domestic and foreign publications devoted to the study of the mechanisms responsible for reducing the value of FVIII activity in donor blood plasma from the moment of donation to the moment of transfusion was carried out. Data on the decrease in FVIII activity at various stages of work with blood plasma are presented. An analysis of methods for preparing samples for studying changes in the values of FVIII in donor blood plasma was performed. The existence of contradictory conclusions about the infl uence on the change in FVIII at the thawing stage of various values of the effects on FFP and poor knowledge of the change in the indicator at the stage of heating to the transfusion temperature after the end of the phase transition in the samples was established. The fundamental differences in the methods of preparing and conducting experiments in previous works are determined. Methods for increasing the reliability of experimental results for studying the thermal lability of FVIII are proposed.

Phase behavior of poloxamer 188 in frozen aqueous solutions – Influence of processing conditions and cosolutes

The aim of the study is to investigate the thermal behavior of poloxamer 188 (P188) in binary (P188-water) and ternary (P188-trehalose-water) solutions during freezing and thawing. The thermal behavior of P188 in frozen (binary and ternary) systems was characterized by differential scanning calorimetry (DSC) and low-temperature X-ray powder diffractometry (XPRD) as a complementary technique. The influence of processing conditions (cooling rate, annealing) and a noncrystallizing co-solute (addition of trehalose) on the behavior of P188 was evaluated during freezing as well as thawing. In rapidly cooled (10 °C/min) aqueous binary solutions, P188 (10% w/v) was retained in the amorphous state. At slower cooling rates (0.5–5 °C/min), the extent of crystallization depended on the cooling rate. In ternary P188-trehalose-water systems (P188 4% w/v, trehalose 0–10% w/v), a concentration dependent inhibition of P188 crystallization was observed with increasing trehalose concentration. However, irrespective of trehalose concentration, annealing resulted in P188 crystallization. The presence of trehalose as well as the processing conditions (cooling rate and annealing) influenced the physical state of P188 at different stages of freezing and thawing. As the cooling rate decreased, the extent of P188 crystallization progressively increased. In presence of trehalose (≥4.0% w/v) crystallization of P188 (4.0% w/v) was inhibited and this effect could be reversed by annealing. Depending on the intended application, the physical form of P188 could be modulated, by annealing even in presence of a noncrystallizing solute.

Phosphorus rather than nitrogen regulates ecosystem carbon dynamics after permafrost thaw

Ecosystem carbon (C) dynamics after permafrost thaw depends on more than just climate change since soil nutrient status may also impact ecosystem C balance. It has been advocated that nitrogen (N) release upon permafrost thaw could promote plant growth and thus offset soil C loss. However, compared with the widely accepted C-N interactions, little is known about the potential role of soil phosphorus (P) availability. We combined 3-year field observations along a thaw sequence (constituted by four thaw stages, i.e., non-collapse and 5, 14, and 22years since collapse) with an in-situ fertilization experiment (included N and P additions at the level of 10gN m-2 year-1 and 10gPm-2 year-1 ) to evaluate ecosystem C-nutrient interactions upon permafrost thaw. We found that changes in soil P availability rather than N availability played an important role in regulating gross primary productivity and net ecosystem productivity along the thaw sequence. The fertilization experiment confirmed that P addition had stronger effects on plant growth than N addition in this permafrost ecosystem. These two lines of evidence highlight the crucial role of soil P availability in altering the trajectory of permafrost C cycle under climate warming.

The establishment of primary cell culture from canine mammary gland tumor

BACKGROUND: In dogs, an insufficient variety of cell lines commercially available or difficulties in obtaining the existing cell lines developed from various studies results in a limited number of cytotoxicity and related molecular studies integrated with clinical practice. Hence, the doses of many drugs or supportive treatments used in canine tumor cases are adjusted based on studies in humans. OBJECTIVE: A cell line was established from a benign mixed tumor of the canine mammary gland. METHODS: Following surgical removal of the tumor, mechanical dissociation, and PBS washing, a culture process of the tumor cells was performed, including the passaging, freezing, and thawing stages. After several passages, the morphological characteristics of the cells at the logarithmic growth phase were observed under a phase-contrast microscope. RESULTS: The microscopy of the cells cultured on plastic dishes revealed monolayer colonies. The average passage time, which was 5–6 days in the first three passages, decreased to 2–3 days after the third passage. Microscopic examination of tumor cells revealed an adherent, stellated, and spindle-shaped structure. CONCLUSIONS: No difference was observed in the viability and morphology of the cells thawed even after the long period of freezing (∼18 months). The different canine cell lines can provide promising molecular applications that can be adapted into practical clinics in veterinary science.

Variations in active layer soil hydrothermal dynamics of typical wetlands in permafrost region in the Great Hing’an Mountains, northeast China

The freeze–thaw process of active layer can alter soil hydrothermal dynamics and plays an important role in the stability of permafrost ecosystem, particularly under the background of permafrost degradation resulting from climate warming. Wetlands in permafrost regions are considered to be symbiotic with permafrost. However, despite being the principal region of high-latitude permafrost in China, research on the freeze–thaw process in wetland in the Great Hing’an Mountains is limited. In this study, soil temperature and moisture data (from September 2018 to August 2020) collected from shrub and forest swamp observational sites in the Great Hing’an Mountains were used to analyze the freeze–thaw process and soil hydrothermal dynamics. The effect of wetland types on the freeze–thaw process and the coupling characteristics of soil temperature and moisture were discussed. The results demonstrated that the thawing process of active layer was unidirectional, while the freezing was bidirectional, and the thawing process took much longer than freezing process. The distribution of temperature and moisture of active layer varied in different stage of freeze–thaw process, yet similar trends were exhibited in different wetland types during the same freeze–thaw stage. The annual average temperature of forest swamp was higher than that of shrub swamp for all soil depths, while the annual average water content of forest swamp was lower than that of shrub swamp. A significant non-linear correlation was observed between moisture and temperature of each soil layer.