Freezing Time Research Articles

In-vitro maturation and transplantation of cryopreserved ovary tissue: understanding ovarian longevity

Research questionIs it possible to use experience gained from 24 years of frozen ovarian transplantation, and from recent experience with in-vitro gametogenesis to accomplish simple and robust in-vitro maturation (IVM) of oocytes from human ovarian tissue? DesignA total of 119 female patients between age 2 and 35 years old underwent ovary cryopreservation (as well as in-vitro maturation of oocytes and IVM in the last 13 individuals) over a 24-year period. Up to 22 years later, 17 returned to have their ovary tissue thawed and transplanted back. ResultsEvery woman had a return of ovarian function 5 months after transplant, similar to previous observations. As observed before, anti-Müllerian hormone (AMH) concentration rose as FSH fell 4 months later. The grafts continued to work up to 8 years. Of the 17, 13 (76%) became pregnant with intercourse at least once, resulting in 19 healthy live births, including six live births from three women who had had leukaemia. Of the harvested germinal vesicle oocytes, 35% developed with simple culture media into mature metaphase II oocytes. ConclusionsThe authors concluded the following. First, ovary tissue cryopreservation is a robust method for preserving fertility even for women with leukaemia, without a need to delay cancer treatment. Second, many mature oocytes can often be obtained from ovary tissue with simple media and no need for ovarian stimulation. Third, ovarian stimulation only be necessary for removing the oocyte from the ovary, which can also be accomplished by simple dissection at the time of ovary freezing. Finally, pressure and just eight ‘core genes’ control primordial follicle recruitment and development.

Experimental study on the compression characteristics of soft soil based on low temperature effect

Based on the characteristics of long annual freezing time and short suitable construction period of soft soil in cold region, this paper discusses the feasibility of foundation treatment of soft soil in freezing-thawing layer under freezing condition. The deformation characteristics of soft soil in freezing-thawing layer in Hulunbuir area in China are studied by using two compression test methods, namely, constant temperature and variable load (CTVL) test, variable temperature and variable load (VTVL) test. The compressibility indexes under different temperatures and consolidation pressures are obtained. The research shows that the freezing-thawing soft soil has large compressibility, the maximum strain of CTVL test is 19.89%, and the maximum compression of VTVL test can reach 18.16%. The results of CTVL compression tests show that when the soil temperature is in the range of severe phase change (-1.5℃-0℃), the temperature change has the greatest influence on the compression coefficient of soil. The result of VTVL compression test shows that some additional deformation occurs under the action of low temperature. The additional deformation is further increased when the soil is under high consolidation pressure and in the severe phase change (-1.5℃-0℃).

Experimental investigation of water desalination using freezing technology

The brackish water desalination process by freezing is a developed technology that becomes a practical option for water desalination due to low energy consumption. This study aims to experimentally investigate the major operating parameters of freezing processes such as freezing time and initial brackish water concentration and their impact on the quality of the treated water. Samples of salty water with different concentrations were processed with different freezing times and the input and output quality of the water were investigated. The results showed that high-quality potable water with a concentration of 215 mg/l could be achieved by processing brackish water with an initial concentration of 2240 mg/l, the required power to produce 1 kg of potable water according to EPA standards is 0.11 kWh.

Evaluation of homeopathic medicine in rats subjected to a hypercaloric diet and stress

Introduction: The factors related to obesity are complex, involving biologic, environmental and neuropsychological mechanisms[1-3]. Among the factors which influence the gain of weight, we can consider the stressful factors. Aims: The aim of this experiment was to evaluate the influence of the commercial homeopathic product compound by Fucus vesiculosus 1cH, Thyroidinum 5cH and Calcarea carbonica 5cH (Besomed®) in the gain of weight in animals submitted to hypercaloric diet and stress. Materials and Methods 40 male freshly weaned Wistar rats, ingesting hypercaloric food, were divided into 4 groups, being two groups submitted to stress by standstill, being one group treated and the other one for control (vehicle) and two more groups without stress being one treated and the other one for control. All were given the drink water ad libidum, in blind, for 2 months. The general activity was evaluated by the Open Field method in 2 steps, one after stress and one after 1 month of treatment. The weekly gain of weight was measured during the whole period of treatment. The data were analyzed by the ANOVA method of two ways followed by the Bonferroni test[4], being p≤0,05. Results: The treatment with Besomed® was effective in reducing only the gain of weight in the animals submitted to stress (p≤0,05); the evaluation of general activity in the Open Field showed increase in the time of freezing of these same animals after receiving the stressful stimulus. Discussion: The medicine is used as auxiliary in obesity treatment, and has the same both endogenous highdiluted molecules as the medicine used by similarity, which is the case of Calcarea carbonica, which, among others is indicated for obesity and hyperlipidemia[5], being observed in this study that the homeopathic complex group gained less weight than the other groups. Stress is capable of disturbing the physiological and psychological homeostasia of an individual, and when the stress is caused by standstill, it may induce behavior of the anxious type. There are also studies relating anxiety and feeding behavior in chronically stressed[6] individuals, showing that consuming a hypercaloric diet induces an anxious behavior[7] in male rats. In this study was not observed any change in the motor activity of animals which passed stress, however the time of freezing of the animals which took Besomed® was the lowest (p≤0,05) after stress, if compared to the control groups, demonstrating the absence of an anxious behavior. Conclusion: The medicine evaluated was effective in reducing weight and in inducing an adaptive behavior only in the stressed animals, reducing the evaluated parameters to the same levels observed in the control group.

Modeling study on sessile water droplet during freezing with the consideration of gravity, supercooling, and volume expansion effects

Droplet freezing phenomenon widely exists in many fields, including aerospace, power production, and cryopreservation, etc. Considering the effects of supercooling, gravity and volume expansion, a theoretical model of droplet freezing is developed. A good agreement is found between the predicted results of freezing front radius and height and experiments for both hydrophilic and hydrophobic surfaces. The developed model also shows good performance in predicting freezing times. The average prediction deviation is 7.63%, and more than 93% simulation results show the deviation within ±15%. Gravity has a more obvious influence on final freezing times with the increase of cold plate temperature, contact angle, and droplet volume. For the droplet freezing process under various contact angles and cold plate temperatures, the fastest average temperature change rates inside water droplet are -2.48 °C/s and -1.72 °C/s, respectively. This study is beneficial for the better understanding of the droplet solidification as well as the optimization of refrigeration and defrosting technologies.

Residual Energy Estimation-Based MAC Protocol for Wireless Powered Sensor Networks.

This paper presents a residual energy estimation-based medium access control (REE-MAC) protocol for wireless powered sensor networks (WPSNs) composed of a central coordinator and multiple sensor devices. REE-MAC aims to reduce overhead due to control messages for scheduling the energy harvesting operation of sensor devices and provide fairness for data transmission opportunities to sensor devices. REE-MAC uses two types of superframes that operate simultaneously in different frequency bands: the wireless energy transfer (WET) superframe and wireless information transfer (WIT) superframe. At the beginning of each superframe, the coordinator estimates the change in the residual energy of individual sensor devices caused by their energy consumption and energy harvesting during the previous superframe. It then determines the devices’ charging priorities, based on which it allocates dedicated power slots (DPSs) within the WET superframe. The simulation results demonstrated that REE-MAC exhibits superior performance for the harvested energy, average freezing time, and fairness to existing representative WPSN MAC protocols.

Metabolic reprogramming mediates hippocampal microglial M1 polarization in response to surgical trauma causing perioperative neurocognitive disorders

BackgroundMicroglial polarization toward pro-inflammatory M1 phenotype are major contributors to the development of perioperative neurocognitive disorders (PNDs). Metabolic reprogramming plays an important role in regulating microglial polarization. We therefore hypothesized that surgical trauma can activate microglial M1 polarization by metabolic reprogramming to induce hippocampal neuroinflammation and subsequent postoperative cognitive impairment.MethodsWe used aged mice to establish a model of PNDs, and investigated whether surgical trauma induced metabolic reprograming in hippocampus using PET/CT and GC/TOF–MS based metabolomic analysis. We then determined the effect of the glycolytic inhibitor 2-deoxy-d-glucose (2-DG) on hippocampal microglial M1 polarization, neuroinflammation, and cognitive function at 3 d after surgery.ResultsWe found that surgery group had less context-related freezing time than either control or anesthesia group (P < 0.05) without significant difference in tone-related freezing time (P > 0.05). The level of Iba-1 fluorescence intensity in hippocampus were significantly increased in surgery group than that in control group (P < 0.05) accompanied by activated morphological changes of microglia and increased expression of iNOS/CD86 (M1 marker) in enriched microglia from hippocampus (P < 0.05). PET/CT and metabolomics analysis indicated that surgical trauma provoked the metabolic reprogramming from oxidative phosphorylation to glycolysis in hippocampus. Inhibition of glycolysis by 2-DG significantly alleviated the surgical trauma induced increase of M1 (CD86+CD206−) phenotype in enriched microglia from hippocampus and up-regulation of pro-inflammatory mediators (IL-1β and IL-6) expression in hippocampus. Furthermore, glycolytic inhibition by 2-DG ameliorated the hippocampus dependent cognitive deficit caused by surgical trauma.ConclusionsMetabolic reprogramming is crucial for regulating hippocampal microglial M1 polarization and neuroinflammation in PNDs. Manipulating microglial metabolism might provide a valuable therapeutic strategy for treating PNDs.

New Minimally Invasive and Tailor-Made Strategy for Cryoballoon Ablation in Patients With Paroxysmal Atrial Fibrillation

The optimal dosage for cryoballoon ablation (CBA) of atrial fibrillation (AF) is still unknown. This study aimed to evaluate the clinical implications of a reduction in the freezing duration to <180 seconds during CBA guided by the time to the target temperature. This study enrolled 325 consecutive paroxysmal AF patients who underwent CBA. It was a retrospective observational study in a single centre. It compared 164 patients who underwent a tailor-made CBA procedure (group T) with 161 who had a standard CBA procedure (group S). In group T, the freezing duration was reduced to 150 seconds when the temperature reached ≤ -40 °C within 40 seconds. Furthermore, it was reduced to 120 seconds when it reached ≤ -50 °C within 60 seconds. In the other patients, the freezing duration was 180 seconds, except for excessive freezing of ≤ -60 °C and/or emergent situations while monitoring the oesophageal temperature, and for phrenic nerve injury, as in group S. In group T, 89 patients (83%) underwent CBA with a reduction in the freezing duration. The total freezing time for each pulmonary vein was significantly shorter in group T than group S, and the total procedure time in group T decreased by an average of 4 minutes compared with group S. The rate of requiring additional radio frequency ablation following the CBA was significantly lower in group T than group S. The AF-free survival rate during the follow-up period (median, 366 days) was similar between the two groups. The safety and efficacy of the new CBA strategy were non-inferior to the standard procedure.

Optimize Initial Freezing Time of Transbronchial Cryobiopsy for the Diagnosis of Interstitial Lung Disease: A Prospective Randomized Parallel Group Study

Background: Transbronchial cryobiopsy (TBCB) is increasingly being identified as a potential alternative for the diagnosis of interstitial lung disease (ILD). The specimen size of TBCB is positively related to the freezing time. However, the proper initial freezing time for the clinical application of TBCB in ILD remains unknown. Methods: A prospective randomized parallel group study was employed to investigate ILD patients with unclear diagnosis, who were admitted to the First Affiliated Hospital of Guangzhou Medical University from May 2019 to October 2020 and required TBCB. All patients were randomly divided into 4 groups according to the different freezing times of TBCB: 3 s, 4 s, 5 s, and 6 s groups. All operations were performed under intravenous anesthesia with endotracheal intubation, 60–65 bar pressure of freezing gas source, and 1.9-mm cryoprobe. Compare differences among groups in specimen size, complications, pathological diagnosis efficiency, and multidisciplinary discussion (MDD) diagnostic efficiency. Results: A total of 100 patients were recruited and randomly assigned into 4 groups (n = 25 each group). The specimen sizes of TBCB in ILD were positively correlated with the freezing time (r = 0.639, p < 0.05). None of the patients experienced Grade 3 severe bleeding. Pneumothorax occurred in 1 patient in the 4 s, 5 s, and 6 s groups, respectively. The diagnostic yield of MDD in the 3 s, 4 s, 5 s, and 6 s groups were 64%, 88%, 88%, and 96%, respectively (p < 0.05), but showing no significant differences among 4 s, 5 s, and 6 s groups. Conclusions: The specimen size and diagnostic efficiency of TBCB in ILD increased with a longer freezing time. When the freezing gas pressure is 60–65 bar, we recommended 4 s as the initial freezing time of TBCB, and this time is associated with high diagnostic efficiency and low incidence of complications.

Experimental analysis of freezing process of stationary food samples inside a hydrofluidisation freezing chamber

• A hydrofluidisation freezing process was experimentally investigated. • A heat transfer coefficient for hydrofluidisation freezing was calculated. • Experiments were performed for various food samples. • Heat transfer coefficient for considered experimental setup exceeded 2000 W · m − 2 K − 1 . • Freezing time for hydrofluidisation freezing and immersion freezing was quantified. Food freezing technologies are one of the most important methods commonly used for food preservation and shelf life extension. In addition to the process effectiveness, modern food freezing techniques should guarantee the high quality of the products after freezing. The hydrofluidisation freezing (HF) is a promising technology that offers short freezing times and high energy efficiency. The heat transfer coefficient (HTC) typical for that method significantly exceeds the HTCs for similar immersion freezing (IF) or popular air-blast freezing. On the other hand, the literature focused on the experimental investigation of the HF is fairly limited. Therefore, the experimental investigation of the laboratory scale HF unit is presented in this paper. The experimental campaign was conducted for the various stationary samples immersed in the HF chamber. A copper sample was used to evaluate the HTC for the investigated system. According to the gathered results the HTC achieved for the investigated HF was equal to 2 941 W · m − 2 K − 1 . In addition, the freezing time for cocktail tomato, blueberry, potato and plum was experimentally determined. The potato samples of various sizes were used to analyse the freezing time for the IF and HF methods. The results of that analysis showed that the freezing time for the HF setup was almost two times shorter for all considered sample sizes. Nevertheless, the freezing time reduction related to the HF employment decreased with the increase of the sample sizes.

Investigations of water droplet impact and freezing on a cold substrate with the Lattice Boltzmann method

A multiphase Lattice Boltzmann model with phase change is presented for studying droplet impact and solidification on an airfoil. The proposed model combines a pseudo-potential multiphase model and a thermal single-component phase change model. These two models are verified separately. The pseudo-potential model with the Peng–Robinson equation of state is used to simulate large density ratios of multiphase flows. The thermal model is based on the total enthalpy and allows the phase change without using an iterative methodology. The coupling is made through the immersed moving boundary method that handles the solid–liquid interface. The generalization for curved surfaces is introduced through to a novel extrapolation method at boundaries. The effects of surface wettability, static contact angle and initial velocity of the droplet on the evolution of solid fraction and total freezing time are discussed and compared to other simulation and experimental works.

Evaluation of Transbronchial Lung Cryobiopsy Freezing Time, Biopsy Size, Histological Quality, and Incidence of Complication: A Prospective Clinical Trial

Background: Transbronchial cryobiopsy (TBCB), a novel way of obtaining a specimen of lung tissue using a flexible cryoprobe, can obtain large lung biopsies without crush artifacts. The freezing time of TBCB was empirically selected from 3 to 7 s in the previous studies. However, no consensus has yet been reached regarding the optimal freezing time used in TBCB. Objectives: The primary endpoint was biopsy size in different freezing times. The secondary endpoints included sample histological quality, diagnostic confidence, and complications in different freezing times. Methods: Patients who were suspected of DPLD requiring histopathological examination for further evaluation were enrolled in this study. Distinct biopsies were obtained by using different freezing times increased from 3 to 6 s sequentially. Samples were reviewed by 2 external expert pathologists. Results: A total of 33 patients were enrolled, and 143 transbronchial cryobiopsies were taken in this trial. An average of 4.33 samples were taken from each patient. The mean biopsy size of different freezing times from 3 to 6 s was 9.10 ± 4.37, 13.23 ± 5.83, 16.26 ± 5.67, and 18.83 ± 7.50 mm², respectively. A strong correlation between freezing time and biopsy size was observed (r = 0.99, p < 0.01). Statistically significant difference of biopsy size was detected in the freezing time of 3 s versus 4 s (p < 0.01) and 4 s versus 5 s (p = 0.02), but not in the freezing time of 5 s versus 6 s (p = 0.10). Overall bleeding in different freezing times from 3 to 6 s was 53.33%, 67.50%, 89.47%, and 77.14%, respectively. A significantly higher overall bleeding was observed when the freezing time exceeded 4 s (RR = 1.67, p < 0.01). Pneumothorax occurred in 4 cases (12.12%). One lethal case (3.03%) was noted 25 days after TBCB. Lung parenchyma was preserved well in all cryobiopsy samples. Thirty-one (93.94%) patients’ histopathological findings were identified as sufficient to establish a CRP diagnosis. There was no statistical difference in diagnostic confidence between different freezing times. Conclusion: A longer freezing time was associated with a larger size of the biopsy sample but a higher risk of bleeding. The optimal transbronchial cryobiopsy freezing time is 3–4 s, which is easily achievable and provides an adequate biopsy size whilst creating a safety threshold from complications.

Fabrication of phase change microcapsules and their applications to anti-icing coating

Phase change materials (PCMs) have been used for energy storage within a wide range of applications. However, they are scarcely used in the field of anti-icing of glass insulators in transmission lines under glaze ice (the icing temperature is 0∼-5 °C). Herein, we prepared phase change microcapsules (MPCMs) and applied them to permanent room temperature vulcanized (PRTV) silicon rubber to prepare anti-icing coating on glass. The n-tetradecane and nucleating agent were used to obtain a requirable phase change temperature. The MPCMs in the coating released latent heat when the temperature dropped from 2.25 to -4.73 °C, which was consistent with the temperature of glaze icing. Furthermore, MPCMs roughened the coating surface and imparted superhydrophobic to the coating. Compared with PRTV coating, the prepared MPCM/PRTV coating extended the freezing time of water droplets from 1381 to 3432 s. Additionally, the MPCMs in the coating could absorb and release energy repeatedly and maintain intactness without cracking during icing/melting cycles, and the anti-icing/deicing performance of the MPCM/PRTV coating demonstrated durability. The heat storage and release of the MPCM/PRTV coating is driven by the temperature difference, thus, we define this coating as having a “temperature switch” effect. The prepared coating shows potential anti-icing applications for glass insulators under glaze ice where the temperature fluctuates within the phase transition temperature range of this coating.

Determination of technological parameters of rock freezing systems based on the condition of maintaining design thickness of ice wall

Artificial freezing ensures the formation of a temporary ice wall around the shaft under construction, which prevents groundwater penetration into the shaft and increases the strength of rocks around the unsupported walls of the shaft until the permanent support is erected. The purpose of the study is to carry out thermotechnical calculation of ice wall with subsequent theoretical analysis of changing ice wall thickness with shifting to the passive freezing stage. The idea of the study is to determine these technological parameters based on the condition of maintaining the design ice wall thickness at the stage of passive freezing. The methodology and results of thermotechnical calculation of ice wall for the clay layer as applied to the case of the shafts under construction of a potash mine in the Republic of Belarus are presented. The thermal calculation of the ice wall was carried out numerically in the ANSYS software package using the finite element method. The findings of the numerical multiparameter modeling allowed theoretical analysis of ice wall thickness decrease with shifting to the passive freezing stage with higher brine temperature. The decrease in ice wall thickness was studied both during normal operation of the freezing station and at emergency operation mode caused by the failure of one of the freezing columns. Special attention in the analysis was paid to studying the influence of the duration of the active freezing stage and the distance between the columns on the decrease in the ice wall thickness. When analyzing changes in ice wall thickness at different distances between the freezing columns, it was found that the most common column spacing in the range from 1.1 to 1.3 m requires observing restrictions on the duration of active freezing to prevent a critical decrease in ice wall thickness during the passive freezing stage or decreasing the distance between the freezing columns. In this case, preservation of positive dynamics of ice wall thickness growth is ensured. For the clay layer considered in the study and the distance between the columns from 1.1 to 1.3 m, the minimum time of active freezing is also about 4.3 months. As a result of the analysis, the technological parameters of the freezing system (duration of the active freezing stage and the distance between the freezing columns) were determined, at which the ice wall thickness at the passive freezing stage did not become lower than the minimum permissible values calculated based on the strength and creep conditions.

Initial experience and follow up on the PolarX cryoablation system compared to the established Arctic Front cryoablation system in PVI ablations

Abstract Introduction Pulmonary vein isolation (PVI) with cryoablation was shown to be comparable to radiofrequency ablation (RF) in terms of safety and outcome for patients with atrial fibrillation (AF), so that both techniques are recommended equally by the current guidelines. A new cryoablation system PolarX® was introduced in 2020. We analysed the first patients, who underwent ablation with the new system with respect to procedural and safety outcome and evaluated the freedom from arrhythmia occurrence in the first 6 months compared to patients treated with the established Arctic Front Advance® cryoablation system. Methods We included the consecutive 44 patients who underwent cryoablation with the new PolarX® cryoablation system (28mm) and 24 patients who underwent cryoablation with the established Arctic Front Advance® cryoablation system (28mm) for paroxysmal AF. We retrospectively analysed baseline characteristics, procedural- and safety data. In 5 patients of each group an additional high-density 3D-mapping was performed, evaluating the scar-area after cryoablation in both groups (figure 1A+B). After 6 months the freedom of AF (by 7d-Holter-ECG) was evaluated in both groups. Results Baseline, procedural characteristics and results are listed in table 1. Mean total procedure duration (“door-to-door-time”) was significantly shorter in the PolarX group compared to the Arctic-Front group (136±34min vs. 163±43min; p&amp;lt;0.05). Number of freezes required to achieve isolation of all pulmonary veins (PVs) and cumulative freezing time was comparable in both groups. Minimal achieved temperatures were significantly lower in the PolarX group vs. ArcticFront group. The scar-area analyzed by 3D-mapping post ablation did not differ in the two groups. Complication rates as well as clinical outcome (freedom from AF) were low and did not differ in the Kaplan-Meier analysis (table 1; figure 1C). Conclusion Based on these initial results, cryoablation with the PolarX cryoballoon seems to be comparably effective and safe, with a significantly shorter procedure time and significantly lower achieved temperatures. Nevertheless, future controlled trials with a longer follow-up period will be necessary to evaluate long-term effectiveness. Funding Acknowledgement Type of funding sources: None.

Freezing characteristics in finned LDPE spherical capsule

The current research examines the findings of the freezing features of PCM in an LDPE spherical capsule fitted with and without fins. De-ionized water is used as phase change material to store energy in form of latent heat. Four fins of length 14mm are inserted in LDPE spherical capsule of same dimension. The effect of fins on the freezing time has been analyzed at various heat transfer fluid temperatures. The experimental results indicated that 50% of the mass of PCM has frozen in 21% and 16% of freezing time with the help of fins when compared to LDPE capsule without fins at -6°C and -9°C bath temperatures. There is not a significant reduction in total freezing time for LDPE spherical capsule with inclusion of fins at all the bath temperatures. A marginal increase in surface heat flux value is observed in case of LDPE finned spherical capsule. Along with heat transfer enhancers, the container material’s thermal conductivity is critical in increasing the freezing rate of PCM.

Potential use of smart coatings for icephobic applications: A review

The formation, adhesion, and accumulation of ice on surfaces can cause both economic and safety issues related to, for example, reduced efficiency in energy generation, increased energy consumption, as well as mechanical and electrical failures. Smart icephobic coatings have attracted significant attention because of their responsive behaviors to external stimuli. Such coatings on exposed surfaces can respond to changes in surrounding environmental conditions or stimuli, such as temperature, electrical and magnetic fields, and pH. Several smart icephobic coatings have been developed; most aim to reduce ice adhesion, decrease the temperature of ice nucleation, and delay freezing time. This review presents recent scientific progress in the realm of smart icephobic coatings. Although these approaches offer a great potential in applications requiring icephobic surface behavior, most related research remains in the early stages and requires more thorough investigation.

Combined Approach of Compression Molding and Magnetic Attraction to Micropatterning of Magnetic Polydimethylsiloxane Composite Surfaces with Excellent Anti-Icing/Deicing Performance.

The accumulation of ice and contaminants on the surface of composite insulators will cause high energy consumption or even major hazards to power systems. In this work, the polydimethylsiloxane (PDMS) silicone rubber was modified by surface micropatterning and material compositing. Highly crosslinked poly(cyclotriphosphazene-co-4,4'-sulfonyldiphenol) (PZS) was used to directly coat ferroferric oxide (Fe3O4) nanoparticles. The obtained core-shell Fe3O4@PZS microspheres were loaded with carbon nanotubes (CNTs) to get CNTs/Fe3O4@PZS as the photothermal magnetic filler. The PDMS/CNTs/Fe3O4@PZS surfaces with micronscale truncated cones were prepared via a combined method of compression molding and magnetic attraction. The 1H,1H,2H,2H-perfluorodecyltrichlorosilane-coated template and magnetic field can increase the height of the microstructure to ∼76 μm and maintain the contact angle of microstructured PDMS/CNTs/Fe3O4@PZS surfaces at a high level (∼152°). Compared with the flat PDMS surface, the micronscale truncated cones extend the freezing time from 4.5 to 11.5 min and also undermine the ice adhesion strength from ∼25 to ∼17 kPa for the microstructured PDMS/CNTs/Fe3O4@PZS surface. The temperature of the PDMS/CNTs/Fe3O4@PZS surface molded with magnetic attraction increases linearly with time and the internal magnetic fillers and achieves 280 °C in 10 s. The efficiency of temperature rise is increased by ∼46%, and hence the entire frozen water droplet can melt within 20 s. The strategy combining active deicing with passive anti-icing undoubtedly promotes the development of high efficiency anti-icing materials and can be applied on insulators to prevent icing flashover.

Interactions of Noradrenergic, Glucocorticoid and Endocannabinoid Systems Intensify and Generalize Fear Memory Traces

Systemic administration of drugs that activate the noradrenergic or glucocorticoid system potentiates aversive memory consolidation and reconsolidation. The opposite happens with the stimulation of endocannabinoid signaling under certain conditions. An unbalance of these interacting neurotransmitters can lead to the formation and maintenance of traumatic memories, whose strength and specificity attributes are often maladaptive. Here we aimed to investigate whether originally low-intensity and precise contextual fear memories would turn similar to traumatic ones in rats systemically administered with adrenaline, corticosterone, and/or the cannabinoid type-1 receptor antagonist/inverse agonist AM251 during consolidation or reconsolidation. The high dose of each pharmacological agent evaluated significantly increased freezing times at test in the conditioning context one and nine days later when given alone post-acquisition or post-retrieval. Their respective low dose produced no relative changes when given separately, but co-treatment of adrenaline with corticosterone or AM251 and the three drugs combined, but not corticosterone with AM251, produced results equivalent to those mentioned initially. Neither the high nor the low dose of adrenaline, corticosterone, or AM251 altered freezing times at test in a novel, neutral context two and ten days later. In contrast, animals receiving the association of their low dose exhibited significantly higher freezing times than controls. Together, the results indicate that newly acquired and destabilized threat memory traces become more intense and generalized after a combined interference acting synergistically and mimicking that reported in patients presenting stress-related psychiatric conditions.

Behavioral and Brain Structural Changes in Kindled Rats Induced by Coriaria Lactone/Pentylenetetrazol.

Epilepsy is a common chronic neurological disease that is characterized by spontaneous seizures. It is commonly comorbid with behavioral and mood disorders. No studies have yet examined the behavioral or structural brain changes associated with coriaria lactone (CL)-induced and pentylenetetrazol (PTZ)-induced kindlings. This study examined whether the increased seizure susceptibility induced by CL/PTZ is accompanied by behavioral impairments and aimed to identify associated structural brain changes. Kindling models were induced using CL and PTZ, with 10 rats in each group. After successful kindling, rats were subjected to brain structural imaging using T2-weighted imaging and underwent behavioral tests, namely, the open field test, water maze tasks, and contextual fear conditioning. Voxel-based morphometry was then used to identify possible brain structural changes associated with kindling and/or behaviors. Support-vector machine learning was also applied for the integrative analysis of behavioral changes and structural brain imaging. In the open field test, both the CL (P = 0.04) and PTZ groups (P = 0.002) spent more time in the central area than the control group. Only the PTZ group (50.29 ± 29.56 s) showed a freezing time that was significantly less than that of the control group (94.8 ± 41.04 s; P = 0.024, Tukey's HSD-corrected) in contextual fear conditioning, which is suggestive of impaired fear-associated learning ability. Furthermore, brain imaging analysis revealed that the gray matter volume (GMV) of the hippocampus changed in both the CL and PTZ groups when compared to control. The support-vector machine learning model indicated that the retrosplenial dysgranular and primary somatosensory cortices were associated with both of the mentioned kindling models. Furthermore, the support-vector regression model results indicated that kindling-associated GMV changes can be used to predict general exploratory activity in the open field test. In conclusion, this is the first study to report greater general exploratory activity in a CL-induced kindling model. Moreover, the general exploratory activity in the open field test can be predicted by the GMV of brain regions associated with kindling.