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Microcrystal electron diffraction (MicroED) has emerged as a powerful technique for unraveling molecular structures from microcrystals too small for X-ray diffraction. However, a significant hurdle arises with plate-like crystals that consistently orient themselves flat on the electron microscopy grid. If the normal of the plate correlates with the axes of the crystal lattice, the crystal orientations accessible for measurement are restricted because the crystal cannot be arbitrarily rotated. This limits the information that can be acquired, resulting in a missing cone of information. We recently introduced a novel crystallization strategy called suspended drop crystallization and proposed that crystals in a suspended drop could effectively address the challenge of preferred crystal orientation. Here we demonstrate the success of the suspended drop approach in eliminating the missing cone in two samples that crystallize as thin plates: bovine liver catalase and the SARS‑CoV‑2 main protease (Mpro). This innovative solution proves indispensable for crystals exhibiting systematic preferred orientations, unlocking new possibilities for structure determination by MicroED.

• Four methods with different cooling rates were applied to the tilapia freezing. • Volatile bases (TBV-N), thiobarbituric acid (TBARS), microstructure were analyzed. • TBV-N, colors parameters and TBARS were statistically significant in all treatments. • Air blast and combined method altered less the texture of fillets after storage time. • Cryogenic freezing showed thermal stress, cracking and tissue quality damaged. The Nile tilapia (Oreochromis niloticus) fillets were frozen with static air (SA) at -20 °C, air blast freezing (AF) at -25 °C, combined method (CM - immersion in liquid nitrogen followed by AF) and cryogenic freezing (CF - immersion in liquid nitrogen). The effects of different freezing methods and of storage time at -18 °C (0, 30, 60 and 90 days) on fillet quality were evaluated. The temperature records were obtained, and the freezing times were determined by monitoring the temperatures of the geometric centers of the fillets. For CF, CM, AF and SA, the freezing times were 5.32, 127, 146 and 268 min, respectively. The quality of the frozen fillets was evaluated by measuring pH, volatile nitrogenous bases (TBV-N), thiobarbituric acid reactive substances (TBARS), and fatty acids and by obtaining a texture profile and performing scanning electron microscopy (SEM). The samples frozen by CF, after storage, had the highest levels of TBV-N because the high freezing rate produced superficial cracks that negatively affected the quality of the fillets. Freezing the samples with SA produced the worst quality indices and the microstructure was visibly damaged, with greater spaces between the fibers left by ice crystals. For all parameters evaluated, freezing with AF and CM resulted in fast freezing rates and better-quality tilapia fillets for 90 days of storage. [Display omitted] [ABSTRACT FROM AUTHOR]

Microcrystal electron diffraction (MicroED) has emerged as a powerful technique for unraveling molecular structures from microcrystals too small for X-ray diffraction. However, a significant hurdle arises with plate-like crystals that consistently orient themselves flat on the electron microscopy grid. If the normal of the plate correlates with the axes of the crystal lattice, the crystal orientations accessible for measurement are restricted because the crystal cannot be arbitrarily rotated. This limits the information that can be acquired, resulting in a missing cone of information. We recently introduced a novel crystallization strategy called suspended drop crystallization and proposed that crystals in a suspended drop could effectively address the challenge of preferred crystal orientation. Here we demonstrate the success of the suspended drop approach in eliminating the missing cone in two samples that crystallize as thin plates: bovine liver catalase and the SARS‑CoV‑2 main protease (Mpro). This innovative solution proves indispensable for crystals exhibiting systematic preferred orientations, unlocking new possibilities for structure determination by MicroED.

In this work, a novel crystal growth method termed suspended drop crystallization has been developed. Unlike traditional methods, this technique involves mixing protein and precipitant directly on an electron microscopy grid without any additional support layers. The grid is then suspended within a crystallization chamber designed in-house, allowing for vapor diffusion to occur from both sides of the drop. A UV-transparent window above and below the grid enables the monitoring of crystal growth via light, UV or fluorescence microscopy. Once crystals have formed, the grid can be removed and utilized for X-ray crystallography or microcrystal electron diffraction (MicroED) directly without having to manipulate the crystals. To demonstrate the efficacy of this method, crystals of the enzyme proteinase K were grown and its structure was determined by MicroED following focused ion beam/scanning electron microscopy milling to render the sample thin enough for cryoEM. Suspended drop crystallization overcomes many of the challenges associated with sample preparation, providing an alternative workflow for crystals embedded in viscous media, sensitive to mechanical stress and/or subject to preferred orientation on electron microscopy grids.

For the preservation of horticultural products, the best results in keeping the attributes and quality at a level as close as possible to that of the fresh product are obtained when artificial cold (refrigeration, freezing) is used, unlike other methods. Among the existing freezing methods, freezing with cryogenic agents allows obtaining average linear freezing rates superior to the other methods. The fastest procedure for cooling food products involves the use of liquid nitrogen, which comes into direct contact with the surface of the food product that needs to be frozen. The paper analyzes the quick freezing process of three species of berries, namely blueberries, strawberries and raspberries, using an experimental model of multifunctional quick-freezing equipment - ICR, developed by INMA Bucharest as part of a national research programme. Total times and average linear freezing rates, as well as liquid nitrogen consumptions for each of the three species subjected to freezing, were tracked. Following the analysis of the experimental data, there were found the following: the minimum total freezing time, 498 s, was recorded for blueberries and the maximum total freezing time, 773 s, was recorded for strawberries; for blueberries and strawberries the average linear freezing rates recorded values of 6.32 cm/h and 6.29 cm/h corresponding to a very fast freezing process and for raspberries the average linear freezing rate recorded a value of 1.62 cm/h corresponding to a fast freezing process; liquid nitrogen consumption recorded a minimum value of 6.90 kg for blueberries and a maximum value of 7.20 kg for raspberries. In the case of blueberries, at the end of the freezing process, cracks and fissures of the epidermis and pulp were observed as a result of the thermal shock induced during the very rapid freezing process. [ABSTRACT FROM AUTHOR]

Hydrogels with excellent mechanical performance, transparency and conductivity properties are attracting much attention as novel materials for use in food packaging, chemical substance detection and bioengineering scaffolds. However, integrating good stretchability, transparency and mechanical performance into a single conductive hydrogel is challenging. In this work, stretchable, transparent and conductive composite hydrogels were fabricated from soy hull nanocellulose (NCFs), sodium alginate (SA) and calcium chloride (CaCl 2) using −80 °C cryogenic freezing, hydrogen and ester bond crosslinking and ion crosslinking methods. The prepared composite hydrogels have a three-dimensional network interior and exhibit excellent tensile (∼900 %), viscoelasticity (storage modulus 78.99 kPa), mechanical strength (compression strength 0.59 MPa, tensile strength 0.61 MPa), transmittance (∼90 %) and electrical conductivity (∼2.34 S/cm) properties. The excellent mechanical properties were retained after repeated stretching. Notably, preservation testing showed that the NCFs/SA/CaCl 2 -5 hydrogel could prolong the shelf life of beef by 5 d at 37 °C, Therefore, the NCFs/SA/CaCl 2 -5 hydrogels can be used in food packaging to extend the shelf life of meat products. Meanwhile, this work provides a new method for preparing tough, transparent and conductive nanocellulose hydrogels. [Display omitted] • NCFs/SA/CaCl 2 composite hydrogels were prepared by cryogenic freezing at −80 °C. • The high crosslinking density maintains mechanical stability of the hydrogels. • The composite hydrogels exhibit excellent stretchable, transparent and conductive. • The hydrogels load of 200 g and multiple torsional stretching without fracture. • The hydrogel prolong the shelf life of beef by 5 d at 37 °C. [ABSTRACT FROM AUTHOR]

The incorporation of red raspberries in bakery and dairy products is limited due to the fragility of the berries. This compromises the appearance of the food product due to the bleeding of juice caused by tissue rupture. In this study, we developed vacuum-impregnated dehydrofrozen red raspberries from fresh fruit. Initially, we optimized drying and freezing conditions for red raspberries that were not vacuum impregnated using air drying alone and in combination with osmotic dehydration, followed by air blasting and cryogenic freezing methods. Later, optimal conditions of partial drying and freezing were used for raspberries that were vacuum impregnated with low methoxyl pectin (LMP) at 10 g of pectin kg−1 of solution and calcium chloride (CaCl2 · 2H2O) at 30 g of calcium kg−1 of pectin. Conditions for the vacuum impregnation of raspberries were based on our previous research. The berries were partially dehydrated using hot air (65 °C) until a final water content of 0.65 g of water g−1 of fruit was reached. Next, the berries were placed in glass jars, sealed, and cooled at 4 °C for 2 h. They were then frozen by air blasting and stored for 2 months at −35 °C prior to evaluation. The mechanical properties of the berries, including the maximum force (FM) and gradient (GC), were considered to be suitable indicators of fruit firmness. Results demonstrate that raspberries impregnated with pectin and calcium and then partially dried and frozen have higher FM and GC values than commercially frozen-thawed berries. These dehydrofrozen raspberries show improved structural integrity for use in bakery and dairy products. [ABSTRACT FROM AUTHOR]

Abstract Undersized crawfish have little economic value and are often discarded. Producing crawfish minced meat (CMM) from undersized crawfish and using an appropriate freezing technique may enable an economically viable market. The objective of this research was to evaluate the effect of the energy removal rate using two techniques, cryogenic freezing (CF) and air blast freezing (BF), on CMM’s quality during frozen storage. CMM was separated into two batches; one batch was cryogenically frozen with liquid nitrogen and the other batch was frozen with an air blast freezer. CMM batches were frozen and stored at − 18 °C. They were analyzed for moisture content, color, pH, and lipid oxidation during 180 days of storage. The CMM yield was 64.67% of the total crawfish weight. Cryogenic freezing achieved the highest freezing rate. Cryogenically frozen CMM showed 22% less lipid oxidation than CMM frozen by air blast freezing at 180 days of storage. This study showed that CMM could be mechanically produced from undersized crawfish and freezing techniques with high energy removal rate could better maintain quality attributes for CMM during frozen storage. Graphical abstract

Microcrystal electron diffraction (MicroED) has emerged as a powerful technique for unraveling molecular structures from microcrystals too small for X-ray diffraction. However, a significant hurdle arises with plate-like crystals that consistently orient themselves flat on the electron microscopy grid. If the normal of the plate correlates with the axes of the crystal lattice, the crystal orientations accessible for measurement are restricted because the crystal cannot be arbitrarily rotated. This limits the information that can be acquired, resulting in a missing cone of information. We recently introduced a novel crystallization strategy called suspended drop crystallization and proposed that crystals in a suspended drop could effectively address the challenge of preferred crystal orientation. Here we demonstrate the success of the suspended drop approach in eliminating the missing cone in two samples that crystallize as thin plates: bovine liver catalase and the SARS‑CoV‑2 main protease (Mpro). This innovative solution proves indispensable for crystals exhibiting systematic preferred orientations, unlocking new possibilities for structure determination by MicroED., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Milk-derived extracellular vesicles (M-EVs) are low-cost, can be prepared in large quantities, and can cross the gastrointestinal barrier for oral administration. However, the composition of milk is complex, and M-EVs obtained by different extraction methods may affect their oral delivery. Based on this, a new method for extracting M-EVs based on cryogenic freezing treatment (Cryo-M-EVs) is proposed and compared with the previously reported acetic acid treatment (Acid-M-EVs) method and the conventional ultracentrifugation method (Ulltr-M-EVs). The new method simplifies the pretreatment step and achieves 25-fold and twofold higher yields than Acid-M-EVs and Ulltr-M-EVs. And it is interesting to note that Cryo-M-EVs and Acid-M-EVs have higher cellular uptake efficiency, and Cryo-M-EVs present the best transepithelial transport effect. After oral administration of the three M-EVs extracted by three methods in mice, Cryo-M-EVs effectively successfully cross the gastrointestinal barrier and achieve hepatic accumulation, whereas Acid-M-EVs and Ultr-M-EVs mostly reside in the intestine. The M-EVs obtained by the three extraction methods show a favorable safety profile at the cellular as well as animal level. Therefore, when M-EVs obtained by different extraction methods are used for oral drug delivery, their accumulation properties at different sites can be utilized to better deal with different diseases., (© 2024 Wiley‐VCH GmbH.)

Ice creams are solid or cream-like products made from a pasteurized mixture of ingredients by freezing. Their texture can be improved by adding egg products because of the emulsifying properties of lecithin and the stabilizing molecules of egg white. Cryogenic freezing is a direct freezing technique, which results in small microcrystals in the product due to rapid heat extraction at the boiling temperature of -195.8 0 C. Aim of the research was to determine if the positive effects of cryogenic freezing on the crystal structure can be combined with the good emulsifying and stabilizing qualities of eggs. In our study, fruit-flavoured (water-based) and chocolate-flavoured (milk-based) ice cream bases containing no egg, 10% liquid whole egg, egg yolk and egg white were frozen with cryogenic and conventional (ice-cream machine) freezing with continuous foaming. The pH was measured by a pH meter, the objective colour by a chroma meter (CIELab) and dry matter content by drying at 105 0 C to constant weight. Besides, the rheological properties of the bases were examined by a rotary rheometer and the hardness of frozen samples by a texture analyzer. The melting and freezing properties were monitored by melting experiment and differential scanning calorimeter. The evaluation was performed by ANOVA. We found that freezing and the addition of liquid egg products is causing significant changes in the lightness and red-green colour attribute. The melting properties of milk-based ice cream changed significantly due to the addition of egg yolk and whole egg. Amount of non-freezing water didn’t change, but the initial temperature of intense melting increased due to the addition of egg products. Texture of the water-based samples became softer due to the addition of whole egg and egg white. In conclusion, the cryogenic freezing and the addition of egg products have a positive effect on the chocolate ice cream. In case of fruit ice cream samples, the addition of egg helped to improve the consistency, however, further experiments could be done, for example, by increasing the level of foaming, so the amount of bounded air could be increased due to the stabilizing ability of the egg white. [ABSTRACT FROM AUTHOR]

Raw oyster meats may be contaminated with Vibrio parahaemolyticus and Vibrio vulnificus. These Vibrio species have been strongly associated with severe and life-threatening conditions in immunocompromised individuals. Post-harvest treatment, such as freezing, affects Vibrio species present in oyster meats and the quality of oysters. This study (a) determined the effect of freezing rate associated with cryogenic freezing (CF) and air-blast freezing (AB) in the removal of heat load and their effect on oyster meat quality, and (b) determined the decimal reduction time and k (inactivation rate) values of V. vulnificus and V. parahaemolyticus in oyster meats that had undergone either CF or blast-freezing (AB) followed by 60 days of storage at −20 ±1 °C. The freezing times for AB and CF oyster meats were 27.9 ± 0.9 and 1.7 ± 0.5 min, respectively. CF oyster meat had a higher freezing rate and energy removal rate (9.9 ± 0.4 °C/min and 23.7 ± 0.8 J/s, respectively) than AB samples (0.6 ± 0.1 °C/min and 1.3 ± 0.2 J/s, respectively). Microscopic observation of oyster meat tissue showed that the lower freezing rate in AB caused severe deformation of muscle tissue. CF and AB had similar D values in reducing V. vulnificus and V. parahaemolyticus in oyster meats. CF and AB reduced V. vulnificus to nondetectable levels by 30 days of storage, while V. parahaemolyticus was decreased to nondetectable levels within 60 days in CF and AB samples. The TBARS (thiobarbituric-acid-reactive-substances) value for CF oyster meat after six months was 47.7% lower than AB, which demonstrated that a higher freezing rate in CF before storage triggered less lipid oxidation compared to AB during the storage. This study showed that freezing could reduce Vibrio spp. to nondetectable levels during storage, and the freezing rate could influence the quality of oyster meats. • Cryogenic freezing (CF) and blast-freezing (AB) reduce V. vulnificus to nondetectable levels by 30 days of storage. • CF and AB have similar decimal reduction times in reducing V. vulnificus and V. parahaemolyticus in oyster meats. • CF has higher freezing and energy removal rates than AB for freezing oyster meats. • The formation of large ice crystals degrades the quality of oyster meat. [ABSTRACT FROM AUTHOR]

The artificial ground freezing (AGF) method has been used in many geotechnical engineering applications such as temporary excavation support, underpinning and groundwater cutoff. The AGF method utilizes a refrigerant such as liquid nitrogen or brine, circulating through embedded freezing pipes in order to freeze the ground. In this paper, two in-situ cryogenic freezing experiments (i.e., single freezing-pipe test and frozen-wall formation test) were performed using liquid nitrogen to simulate the AGF in a Korean marine clay deposit, in which the freezing rate was evaluated. The thermal conductivity of frozen and unfrozen marine clay was evaluated by performing typical laboratory experiments. In addition, the strength and stiffness of frozen-thawed deposits were comparatively measured by sounding tests (i.e., piezocone penetration test and lateral loading test). The freezing rate of the frozen-wall formation test in the Korean marine clay deposit was approximately twice as high as that of the single freezing pipe test. Compared to the original marine clay deposit, the frozen-thawed marine clay showed a significant reduction in strength and stiffness. [ABSTRACT FROM AUTHOR]

Fresh date fruits, especially Barhi cultivar, are favored and widely consumed at the Khalal maturity stage (first color edible stage). These fruits are seasonal and perishable and there is a need for extending their shelf life. This study evaluates two different freezing methods, namely cryogenic freezing using liquid nitrogen and conventional deep freezing on preserving the quality and stability of date fruits (cv. Barhi) at Khalal maturity stage. Fresh date fruits (cv. Barhi) at Khalal stage were frozen utilizing the two methods. The produced frozen dates were stored under frozen storage conditions for nine months (at −20 °C and −40 °C for the conventional and cryogenic freezing, respectively). Color values, textural properties (hardness, elasticity, chewiness and resilience), and nutrition attributes (enzymes and sugars) for fresh dates before freezing and for the frozen dates were measured every three months during the frozen storage. Color values of the frozen dates were affected by the freezing method and the frozen storage period. There are substantial differences in the quality of the frozen fruits in favor of cryogenic freezing compared to the conventional slow freezing. The results revealed a large disparity between the times of freezing of the two methods. The freezing time accounted to 10 min in the cryogenic freezing method, whereas it was 1800 min for the conventional slow freezing system.

This study was conducted to investigate the potential of cryogenic freezing with liquid nitrogen in the shelf-life extension of northern snakehead (Channa argus) and clarify the effects of temperature fluctuations after freezing on the quality attributes and tissue microstructure during frozen storage. The fish fillets were frozen by three methods including freezing using an ultra-low-temperature freezer (−80°C) to the core temperature of −60°C (T1) or −18°C (T2), or liquid nitrogen (T3) followed by storage at −20°C for five months. Cryogenic freezing with liquid nitrogen postponed the decrease in pH and protein extractability. Temperature fluctuations after freezing might promote the accretion of ice crystals and resulted in the loss of tissue integrity and disorganization of myofibrils. The microstructural changes contributed greatly to the increased thawing loss and decreased resilience, as indicated by the enlarged extracellular spacing and the flakiness of myofibrils. Cryogenic freezing with liquid nitrogen showed no superiority in maintaining the microstructure of northern snakehead fillets, which was supposedly attributed to the cracking in tissue during freezing and the accretion of ice crystals during frozen storage.

The enhanced interest in greater convenience foods has recently led to the expansion of minimally processed potato products. This study investigated the effects of isochoric freezing on pre‐peeled potato cubes, including quality attributes (microstructure, texture, and color), nutritional value (ascorbic acid (AA) content, total phenolic content, and antioxidant capacity), and polyphenol oxidase activity. Isochoric freezing (−3 °C/30 MPa) was compared with isobaric freezing (−3 °C/0.1 MPa) and individual quick freezing followed by frozen storage at −20 °C for 4 weeks. The isochoric sample had lower drip loss and volume shrinkage as well as better preserved texture and microstructure than the other samples. All freezing methods caused an increase in total phenolic content and antioxidant capacity, but a decrease in AA content. Also, all freezing methods caused browning of the thawed potatoes, but isochoric freezing delayed its onset for more than 1 week. Practical Application: Results showed that isochoric freezing of pre‐peeled and cut potatoes caused less freeze damage than isobaric and individual quick freezing, which might find application in the commercial preservation of minimally processed food products. [ABSTRACT FROM AUTHOR]

As bayberry has no peel with active respiration, it is almost impossible to store fresh bayberry in high quality for more than one day. The difficulty of freshness preservation is the biggest problem constraining the bayberry industry. Quick freezing offers a fast freezing rate to decrease the size of the ice crystals, which is an effective way to maintain the quality of bayberry. The freezing point of the bayberry flesh was firstly measured as -0.1 °C by the electrical resistance method. Numerical simulation was utilized to analyze the heat transfer process of bayberry freezing. The results shows that bayberries won't be quickly frozen in a domestic freezer (-18 °C), but can be quickly frozen in a cryogenic freezer. The experiments of the bayberry frozen under different processes (-18, -60, -9 0 and -120 C) were conducted. After freezing and storage under - 1 8 'C for 6 months, the quality of bayberries were studied for the first time, including the thawing loss, pH value, texture, color, macro and micro features. It can be concluded that a faster freezing rate led to a better quality after storage and thawing. The best freezing rate for maintaing the freshness of postharvest bayberry was 8.51 cm/h at -120 °C. [ABSTRACT FROM AUTHOR]

The freezing rate determines the ice crystal size distribution and morphology. Ice crystal characteristics may have a direct impact on the microstructure of food products, providing irreversible cell and tissue damages resulting in quality losses. In this paper, an innovative method was used for imaging and quantifying ice crystals directly in frozen samples of minced beef by X-ray micro-computed tomography. The results were compared to those obtained by X-ray micro-computed tomography on freeze-dried samples. The effects of the integral cooling rate on ice crystal characteristics were studied for various mechanical and cryogenic freezing operating conditions. It was pointed out that crystals become 2.5 times smaller when the freezing temperature goes down from −30 °C to −100 °C. These crystals are also more numerous with a narrower distribution. Fluorescence optical microscopy and electron scanning microscopy were also used to do qualitative analysis. These results confirmed the effect of the freezing temperature on ice crystal sizes. • Frozen beef microstructure was quantified by X-ray micro-computed tomography. • Freeze-dried samples were analyzed using SEM and fluorescence microscopy. • Imaging frozen sample could give more reliable results than imaging freeze-dried ones. • Freezing rates affected ice crystal sizes and numbers. • Due to food thermal resistance, bigger crystals were observed at the center of the product. [ABSTRACT FROM AUTHOR]

Abstract The permeability of coalbed methane (CBM) reservoirs is typically very low and it is challenging and essential to effectively increase coal permeability to maximize CBM recovery. An exploratory study on enhancing coal porosity/permeability using freeze−thaw cycling with liquid nitrogen (LN 2) was conducted. The changes of fracture and porosity in coal with the freeze−thaw treatment using LN 2 were evaluated using nuclear magnetic resonance (NMR). After freeze−thaw treatment, the coal pore size tended to increase and new pores/fissures were generated. The growth rate of the pore size was positively correlated with the LN 2 freezing duration. The effective porosity had a positive correlation with the freezing duration, but the correlation for residual porosity was negative. This means that the volume of irreducible fluid in the coal decreased while the amount of free fluid increased. Scanning electron micrograph studies indicated that the maximum fracture width in the coal samples grew from 5.56 μm at a T freezing = 1 min to 100 μm for T freezing = 60 min, matching the NMR findings. This study provides a scientific basis and guidance for engineering application of freeze−thaw using liquid nitrogen to enhance coalbed methane extraction. Highlights • NMR was used to conduct the evolution of pore structure in coal samples. • Coal pore size and effective porosity increase with increasing LN 2 freezing time. • A method of LN 2 frozen-thawed fracturing for CBM extraction was proposed. [ABSTRACT FROM AUTHOR]

Highlights • A new cryogenic sealing process for the launch and reception of a tunnel shield is proposed. • It freezes the ground water flowing through local low temperature environment. • A full-scale field experiment is designed to validate the feasibility of the sealing process. • Experimental results indicate that the process has a good sealing capacity. Abstract The success of a shield's launch and reception processes for tunnels in sandy grounds with high water tables depends heavily on the ground improvement of the soils within the portal zone. To achieve this, a sealing process based on the cryogenic freezing principle is herein proposed. This process involves using liquid nitrogen as the working fluid to create a cryogenic environment, through which passing underground water would be frozen to create a seal. To confirm the feasibility of this method, full-scale experimental field tests were conducted, which include the design of the experimental device, the experimental process, and preparation of the experimental mud sample. The experimental results indicate that a thermal additive could accelerate the freezing speed, and the frozen device had a good sealing capacity when the hydraulic pressure was over 0.15 MPa. Additional information on the implementation of the feasibility test was also reported. [ABSTRACT FROM AUTHOR]

• The compressive properties of ECC after freeze–thaw damage were explored at −18 °C. • The prestress was assumed to be provided by the effective frost heave stress. • The prestressed compressive strength model of ECC in a freezing state was derived. • The effective strength of ECC in a freezing state was predicted and analyzed. Engineered cementitious composite (ECC) is characterized by excellent strain-hardening properties and strong crack-control abilities. However, in the freezing-thawing environment of some cold regions, the concrete materials, including ECC, are subject to varying degrees of freeze–thaw (FT) damage. This paper investigates the impacts of the cryogenic freezing environment on the evolutionary mechanism of the pore structure and compressive properties of ECC. A nuclear magnetic resonance (NMR) T 2 spectrum experiment and uniaxial compression experiment at −18 °C were conducted on ECC with 0 to 300 freeze–thaw cycles (FTs). The results indicated that, as the number of FTs increased, the distribution curves of the NMR T 2 spectrum exhibited three peaks. Meanwhile, the drop rate of the compressive stress–strain curves in the freezing state was less than that in the thawing state, and the compressive strength, elastic modulus, and peak strain in the freezing state were higher than those in the thawing state, respectively. Based on the elastic mechanics theory and experimental analysis, the pore frost heave stress equivalence and cryogenic freezing strength equivalence were proposed, and the prestressed compressive strength model of ECC with FT damage in the cryogenic freezing state was developed. It was found that the model prediction results were well consistent with the experimental values. [ABSTRACT FROM AUTHOR]

Freeze-thaw and earthquake are significant factors for the stability and failure of moraine soil slopes in high-altitude cold and strong earthquake area. The cryogenic freezing (CF) and heat thawing (HT) of moraine soil slopes were completed by using a self-designed constant-temperature test chamber, and several shaking table tests under different seismic intensity were carried out. In these tests, the displacement and acceleration responses were recorded by the non-contact measurement system and accelerometers, and the slope dynamic responses were clarified by the displacement, acceleration and energy. The results showed that: (1) the seismic responses of the CF slope are larger than that of the HT slope. (2) The failure process of the CF slope under earthquakes could be summarized into three phases: elastic deformation phase with seismic magnitude <0.4 g, brittle failure phase with seismic magnitude from 0.4 g to 0.8 g, and failure slip phase with seismic magnitude >0.8 g. (3) The failure mode of the HT slope is characterized by the overall collapse of loose moraine soil, and the particle size of the collapsed moraine soil redistributes during the sliding process. The failure mode of CF slope is a frozen block landslide with the soil-ice interface as the sliding surface. (4) The peak acceleration of the input wave, slope surface and elevation have amplification effect on the slope dynamic response, and the top of slope surface is the main deformation and failure area. (5) Reinforcement measures such as soil improvement of slope surface, weight reduction at slope top and backpressure at slope toe, heat pipes are recommended for moraine soil slopes in cold and strong earthquake area. Such findings may provide scientific basis for the damage state identification and seismic reinforcement of moraine soil slopes in alpine and strong earthquake areas. • Seismic responses of cryogenic-freezing slopes are larger than that of heat-thawing slopes • Failure processes of CF slopes include elastic deformation, brittle failure and failure slip phases • Failure modes include overall collapse of loose moraine soil and frozen block landslide • Peak acceleration, slope surface and elevation amplify slope dynamic response • Reinforcement measures for moraine-soil slopes are recommended [ABSTRACT FROM AUTHOR]

In this work, a novel crystal growth method termed suspended drop crystallization has been developed. Unlike traditional methods, this technique involves mixing protein and precipitant directly on an electron microscopy grid without any additional support layers. The grid is then suspended within a crystallization chamber designed in-house, allowing for vapor diffusion to occur from both sides of the drop. A UV-transparent window above and below the grid enables the monitoring of crystal growth via light, UV or fluorescence microscopy. Once crystals have formed, the grid can be removed and utilized for X-ray crystallography or microcrystal electron diffraction (MicroED) directly without having to manipulate the crystals. To demonstrate the efficacy of this method, crystals of the enzyme proteinase K were grown and its structure was determined by MicroED following focused ion beam/scanning electron microscopy milling to render the sample thin enough for cryoEM. Suspended drop crystallization overcomes many of the challenges associated with sample preparation, providing an alternative workflow for crystals embedded in viscous media, sensitive to mechanical stress and/or subject to preferred orientation on electron microscopy grids., (open access.)

Summary: Cryogenic transmission electron microscopy of high‐pressure freezing (HPF) samples is a well‐established technique for the analysis of liquid containing specimens. This technique enables observation without removing water or other volatile components. The HPF technique is less used in scanning electron microscopy (SEM) due to the lack of a suitable HPF specimen carrier adapter. The traditional SEM cryotransfer system (PP3000T Quorum Laughton, East Sussex, UK; Alto Gatan, Pleasanton, CA, USA) usually uses nitrogen slush. Unfortunately, and unlike HPF, nitrogen slush produces water crystal artefacts. So, we propose a new HPF specimen carrier adapter for sample transfer from HPF system to cryogenic‐scanning electronic microscope (Cryo‐SEM). The new transfer system is validated using technical two applications, a stearic acid in hydroxypropyl methylcellulose solution and mice myocardium. Preservation of samples is suitable in both cases. Cryo‐SEM examination of HPF samples enables a good correlation between acid stearic liquid concentration and acid stearic occupation surface (only for homogeneous solution). For biological samples as myocardium, cytoplasmic structures of cardiomyocyte are easily recognized with adequate preservation of organelle contacts and inner cell organization. We expect this new HPF specimen carrier adapter would enable more SEM‐studies using HPF. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effects of convectional (F) and cryogenic (N) freezing, as well as convective drying (C) temperatures of 60, 70, 80 and 90 °C on the physical, morphological and thermal properties of cranberries. Convectional (F) freezing induced considerable texture modification and cell structure disruption, whereas cryogenic (N) freezing led to freeze cracking. Depending on pretreatment and drying conditions, convective drying of whole cranberries lasted from 5 to 195 h. Freezing significantly increased the rate of moisture removal in the first stage of drying, and it shortened drying time by up to 43%. Convectional freezing combined with hot air drying at a low temperature (60 °C) induced minimal changes in the surface structure of dried samples and produced fruits whose overall appearance was similar to that of unprocessed berries. Cryogenic freezing combined with hot air convective drying contributed to the greatest changes in the properties of cranberries. An increase in air temperature from 60 to 70, 80 and 90 °C shortened the drying time of cranberries by up to 69-97%. However, the increase in drying air temperature was accompanied by structural changes in cranberries. [ABSTRACT FROM AUTHOR]

Electron beam (e-beam) treatment of tool steel surfaces has been available for several decades as an approach to create hard surface layers on tool steels. The e-beam process produces ultrafine grain sizes through ultra-rapid cooling of the melt layer, which helps with improving wear resistance to increase the service life of tools. However, its implementation in many applications has been limited by the accompanying residual tensile stresses in the surface layer, which is undesirable and may lead to premature fracture. Here we report the utilization of cryogenic freezing after e-beam treatment to reduce the residual tensile stress. The e-beamed specimen contained high levels of retained austenite in the surface layer. The cryogenic treatment converted the retained austenite into martensite, and the corresponding volume expansion reduced the peak tensile residual stress by 28%, which makes it a promising method to expand the applications of e-beamed tool steel. [ABSTRACT FROM AUTHOR]

Blueberries are a widely consumed fruit known for their high antioxidant content. Due to their short shelf life at refrigerated temperatures, they can be frozen or dried to overcome perishability limitations. Liquid nitrogen pretreatment may be able to increase the permeability of blueberries’ skin, thereby amplifying the effects of osmotic dehydration through increased transfer of moisture and solids. This study evaluated the effects of liquid nitrogen pretreatment on osmotic dehydration and the resulting physicochemical properties of cryogenically frozen blueberries. Blueberries were immersed in liquid nitrogen (− 196 °C) for 10 s and then thawed. Pretreated and un-pretreated samples were placed in a 60°Brix sucrose solution (40 °C) for 8 h, followed by cryogenic freezing. Liquid nitrogen pretreated blueberries experienced greater moisture loss and solids gain than un-pretreated samples after osmotic dehydration, while having similar anthocyanin and total phenolic contents. This study demonstrated that liquid nitrogen pretreatment facilitates water and sugar diffusion in blueberries during osmotic dehydration while maintaining nutritional quality. [ABSTRACT FROM AUTHOR]

This study was conducted to investigate the potential of cryogenic freezing with liquid nitrogen in the shelf-life extension of northern snakehead (Channa argus) and clarify the effects of temperature fluctuations after freezing on the quality attributes and tissue microstructure during frozen storage. The fish fillets were frozen by three methods including freezing using an ultra-low-temperature freezer (−80°C) to the core temperature of −60°C (T1) or −18°C (T2), or liquid nitrogen (T3) followed by storage at −20°C for five months. Cryogenic freezing with liquid nitrogen postponed the decrease in pH and protein extractability. Temperature fluctuations after freezing might promote the accretion of ice crystals and resulted in the loss of tissue integrity and disorganization of myofibrils. The microstructural changes contributed greatly to the increased thawing loss and decreased resilience, as indicated by the enlarged extracellular spacing and the flakiness of myofibrils. Cryogenic freezing with liquid nitrogen showed no superiority in maintaining the microstructure of northern snakehead fillets, which was supposedly attributed to the cracking in tissue during freezing and the accretion of ice crystals during frozen storage. [ABSTRACT FROM AUTHOR]

Fresh date fruits, especially Barhi cultivar, are favored and widely consumed at the Khalal maturity stage (first color edible stage). These fruits are seasonal and perishable and there is a need for extending their shelf life. This study evaluates two different freezing methods, namely cryogenic freezing using liquid nitrogen and conventional deep freezing on preserving the quality and stability of date fruits (cv. Barhi ) at Khalal maturity stage. Fresh date fruits (cv. Barhi ) at Khalal stage were frozen utilizing the two methods. The produced frozen dates were stored under frozen storage conditions for nine months (at −20 °C and −40 °C for the conventional and cryogenic freezing, respectively). Color values, textural properties (hardness, elasticity, chewiness and resilience), and nutrition attributes (enzymes and sugars) for fresh dates before freezing and for the frozen dates were measured every three months during the frozen storage. Color values of the frozen dates were affected by the freezing method and the frozen storage period. There are substantial differences in the quality of the frozen fruits in favor of cryogenic freezing compared to the conventional slow freezing. The results revealed a large disparity between the times of freezing of the two methods. The freezing time accounted to 10 min in the cryogenic freezing method, whereas it was 1800 min for the conventional slow freezing system. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effects of stepwise dry/wet-aging and freezing method on quality attributes of beef loins. Paired loins ( M. Longissimus lumborum ) from eight carcasses were assigned to either stepwise dry/wet-aging (carcass dry-aging for 10 days then further wet-aging for 7 days in vacuum bags) or carcass dry-aging only for 17 days. Then, each loin was divided into three sections for freezing (never-frozen, blast or cryogenic freezing). Stepwise dry/wet-aged loin had lower purge/drip loss and shear force than conventionally dry-aged loin ( P < 0.05), but similar color and sensory characteristics ( P > 0.05). The cryogenic freezing resulted in a significant decrease in shear force values and a significant improvement in water-holding capacity (WHC). These findings indicate that the stepwise dry/wet-aging coupled with cryogenic freezing could provide beneficial impacts to the local meat industry by providing equivalent quality attributes as conventional dry-aging and improving WHC of frozen/thawed meat, while reducing the time needed for dry-aging. [ABSTRACT FROM AUTHOR]

A combination of steam-venting packaging and microwave cooking may be used to inactivate Vibrio vulnificus and Vibrio parahaemolyticus in oyster meat. This study investigated temperature and pressure profiles in the headspace of a steam venting package with the steam-generated inside of the package resulting from microwave heating. To determine steam venting time to inactivate pathogens, fresh oyster meat (Crassostrea virginica) was inoculated with either Vibrio vulnificus or Vibrio parahaemolyticus , cryogenically frozen (−20 °C), and packaged in microwavable trays in 50 and 100 g portions. Trays were film sealed with nitrogen in the headspace and stored in a freezer for 12 h. The film acted as a barrier against rapid moisture loss and promoted even temperature distribution in the oyster meat. Steam venting occurred due to steam pressure generated inside the package. Venting was used to prevent overheating. Data collection of temperature and pressure inside the package during microwaving was performed in a Microwave Workstation using fiber optic temperature and fiber optic pressure sensors. Temperature and pressure profiles showed that after 10 s of heating, the temperature of the oyster meat was the same both internally and upon the surface. The venting time in the 100 g package took 1.53 times longer than in the 50 g package, while the venting pressure was 52% lower than in the 50 g package. After 50 s and 60 s of microwave cooking at 100% power on 50 g and 100 g of oyster meat, respectively, total inactivation of both pathogens was achieved. The study demonstrated the steam venting package, and microwave heating could provide even heating, prevent overheating, and inactivate pathogens. • Steam venting package and microwave heating provided even heating in oyster meat. • Optical fiber sensing is an excellent tool for temperature measurement during microwave heating. • Steam venting package and microwave heating inactivate pathogens in less than 1 min. • Steam venting package film prevented moisture loss in oyster meat during microwaving. [ABSTRACT FROM AUTHOR]

Radiofrequency-assisted nitrogen cryogenic freezing previously proposed was optimized to increase meat quality. Continuous cryogenic (CCF, for 2.5 min) and pulsed cryogenic (PCF, 3 s pulse with 10 s interval for 10 min) freezing were set up. CCF and PCF were then combined with radiofrequency (RF) pulses to set up RF-CCF (10 s 2 kV RF pulse with 20 s interval during 2.5 min of continuous N 2 flow) and RF-PCF (30 s 2 kV RF pulse with 60 s interval, during 3 s nitrogen pulse with 10 s interval for 10 min). These processes were compared with slow (SF) and blast (BF) freezing. Meat quality (i.e. , microstructure, drip loss, color, firmness) decreased in the order RF-PCF ≥ PCF > RF-CCF > BF > SF > CCF, indicating that nitrogen pulsing considerably reduced tissue damages and its combination with RF was crucial to further preserve tissue integrity. RF-PCF could be adapted to different matrices by tuning processing conditions. • Radiofrequency (RF) nitrogen cryogenic freezing of meat was optimized by a pulsing approach. • Nitrogen pulsing during meat freezing reduced tissue damage. • RF pulsing was modulated to guarantee homogeneous cryogenic freezing of meat. • Combining nitrogen pulses with RF was crucial to preserve meat microstructure. [ABSTRACT FROM AUTHOR]

Highlights: [•] Approximate methods for freezing time are compared with results of numerical methods. [•] The comparison included low moisture content, low freezing point foods and cryogenic temperatures. [•] Pham’s (1984) method was most accurate, followed by Pham’s (1986) method. [•] Correction factors are found to allow Pham’s methods to be used in all cases. [•] Mascheroni and Calvelo’s three-stage approach is vindicated. [ABSTRACT FROM AUTHOR]