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AbstractAtmospheric freeze-drying (AFD) is a relatively new freeze-drying technology without the need for a vacuum, making it easy to operate and cost-effective. Although there have been studies using AFD to dehydrate solid foods, there is currently no research on using AFD to dehydrate frozen liquids in pharmaceutical vials. In this study, several approaches were evaluated to enhance the atmospheric sublimation of water in pharmaceutical vials. Using −4 °C impinging jet airflow to dry frozen water samples in the vial, it was found that convective action significantly affected the sublimation rate. On this basis, a 3D-printed air-guide model was designed to improve airflow circulation in the vial, and it was found that the drying rate was highest when airflow energy loss was minimized, and airflow velocity at the sample surface was maximized. Additionally, the geometric characteristics of the vial also influenced the sublimation rate; vials with a larger bottom area and shorter height showed the highest sublimation rate. Increasing the vial’s bottom radius from 11 mm to 13 mm, under atmospheric pressure and using cold air at approximately −5 °C, reduced the drying time of 1 g of frozen water from 8.5 h to 6 h; each 5 mm height increase added 0.5 h to the drying time. Using cold air at −10 °C to dry 1 g of frozen water in a 5 mL vial, the combination of ultrasonic-induced energy (at a frequency of 39.46 kHz) and the air-guide model effectively reduced the sublimation time from 7 h to 5 h, compared to using only the air-guide model. However, this technique may be vulnerable to melting at the vial-transducer contact point, should the transducer be directly attached to the vials. [ABSTRACT FROM AUTHOR]

The accumulation of frozen liquid around a central passageway of melt as it flows through a freezing region can make calculations very challenging. To both illustrate and to quantify some of these challenges from freezing, a model equation is developed. It simplifies the solution of Holmes (2007, https://gfd.whoi.edu/wp-content/uploads/sites/18/2018/03/MHolmesGFDReport%5f30151.pdf) for low Reynolds number single component liquid flow through a long tube that has a wall kept at subfreezing temperature. This model equation is used in conjunction with three different upstream configurations, each with parameters expressing their behavior. Analytical and numerical results give the parameters that have criteria for: the freezing of a compressible upstream reservoir that includes oscillatory behavior; the freezing of flow fed through a constriction with a large upstream pressure, just like a dripping water faucet during winter; the evolution of flow in multiple tubes connected by an upstream manifold, where some tubes end up with full flow and others freeze shut. Numerical runs with 1,000 tubes give a formula for the spacing between actively flowing (non‐frozen) tubes over wide ranges of the two upstream parameters (flow rate and manifold resistance). Results have implications in various areas in earth science. Some are: oscillatory and freezing shut criteria for flow of magma from a compressible region, a criterion for wintertime ice accumulation at natural springs, and the spacing between volcanos. Plain Language Summary: The dynamics of liquid flow in an upstream region are considered in conjunction with flow through a freezing region. This is because when liquid flows into a freezing region, the resistance change that arises from the accumulation of solid modifies the upstream pressure and flow rate in both upstream and freezing regions. This study shows examples of three different upstream situations with dynamic interaction between upstream and freezing regions. The interaction leads to complicated results such as oscillations, intense flow channelization in subfreezing surroundings, and complete freezing shut in some portions of the downstream region. Through the use of three examples, the fundamental nature of the interaction between upstream and freezing flows helps to begin to explain the complicated nature of freezing flows in Earth Science. Key Points: A simple model is developed for liquid flow into a freezing tubeThree upstream conditions are considered: compressible, throttled, and multiple tubes fed by a manifoldTimes and locations of freezing are quantified [ABSTRACT FROM AUTHOR]

Repeatable and reliable site-specific preparation of specimens for atom probe tomography (APT) at cryogenic temperatures has proven challenging. A generalized workflow is required for cryogenic specimen preparation including lift-out via focused ion beam and in situ deposition of capping layers, to strengthen specimens that will be exposed to high electric field and stresses during field evaporation in APT and protect them from environment during transfer into the atom probe. Here, we build on existing protocols and showcase preparation and analysis of a variety of metals, oxides, and supported frozen liquids and battery materials. We demonstrate reliable in situ deposition of a metallic capping layer that significantly improves the atom probe data quality for challenging material systems, particularly battery cathode materials which are subjected to delithiation during the atom probe analysis itself. Our workflow design is versatile and transferable widely to other instruments., Competing Interests: Conflict of Interest The authors declare that they have no competing interest., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Microscopy Society of America.)

Freeze casting offers a tremendous opportunity to obtain bio-inspired synthetic materials that mimic microstructural characteristics of natural materials like bone and nacre. These natural materials display high strength and toughness; properties usually desired in synthetic engineering materials. The freeze casting process involves four basic steps. The ceramic slurry preparation consists of fine ceramic particles that are suspended in a fluid. In the current work, water based kaolin suspensions were prepared varying the volume fraction of ceramic particles. After the ceramic slurry is properly prepared, the slurry is frozen. The solidification process is often performed using directional freezing, which creates laminar pores, providing the microstructural characteristics of the final part. When a crystal is formed the frozen front moves the particles around it, allowing particles to agglomerate around the crystal, creating different types of pores. In the present study, freezing rates were varied. Subsequently, the samples have to be lyophilized in order to sublimate the frozen liquid phase. Sublimation is the transformation of a solid phase directly to the gas phase. As a result the lyophilized sample has a porous structure with a replica of the water crystals formed during freezing. As a final step, sintering of ceramics is performed. Results of the microstructural characteristics of the samples revealed that varying the volume fraction of ceramic particles and freezing rates have a direct influence on the pore characteristics, changing from circular to laminar pores. [ABSTRACT FROM AUTHOR]

The present study was conducted to determine the effects of supplementing α-linolenic acid (ALA) into BioXcell ® extender on post-cooling, post-thawed bovine spermatozoa and post thawed fatty acid composition. Twenty-four semen samples were collected from three bulls using an electro-ejaculator. Fresh semen samples were evaluated for general motility using computer assisted semen analyzer (CASA) whereas morphology and viability with eosin–nigrosin stain. Semen samples extended into BioXcell ® were divided into five groups to which 0, 3, 5, 10 and 15 ng/ml of ALA were added, respectively. The treated samples were incubated at 37 °C for 15 min for ALA uptake by sperm cells before being cooled for 2 h at 5 °C. After evaluation, the cooled samples were packed into 0.25 ml straws and frozen in liquid nitrogen for 24 h before thawing and evaluation for semen quality. Evaluation of cooled and frozen-thawed semen showed that the percentages of all the sperm parameters improved with 5 ng/ml ALA supplement. ALA was higher in all treated groups than control groups than control group. In conclusion, 5 ng/ml ALA supplemented into BioXcell ® extender improved the cooled and frozen-thawed quality of bull spermatozoa. [ABSTRACT FROM AUTHOR]

Abstract: Despite their great potential, gene delivery polyplexes have a number of limitations, including their tendency for aggregation in vivo or upon storage. In previous studies, we could show that hydroxyethyl starch (HES)-decoration of polyplexes reduces aggregation in vitro and in vivo. The current study investigates the ability of HES-decoration to improve the stability of polyplexes upon storage as frozen-liquid or lyophilizate, and uses naked polyplexes or PEGylated ones as controls. For this purpose, freeze-thaw (FT) experiments of the polyplexes were conducted in the presence of standard excipients (glucose, sucrose or trehalose). Dynamic light scattering (DLS) measurements showed that HES-decoration imparted better stability when glucose was used, while both HES and PEG were effective in inhibiting aggregation in the presence of trehalose or sucrose. In contrast, the lyophilized HES-coated polyplexes were more stable than the PEGylated ones as shown by DLS, even after storage for 10 weeks at an elevated temperature. Evaluation of the gene transfer efficiency of the stored samples showed no negative effect of storage, except for the lyophilized naked polyplexes. In general, this study shows that, while both HES- or PEG-coats could prevent aggregation under frozen-liquid storage, the HES-coat resulted in superior protective effect upon lyophilization, with possible advantages for in vivo application. In summary, our developed HES-coats provided effective cryo- and lyoprotection to the DNA polyplexes. [Copyright &y& Elsevier]

Abstract: The detailed vertical compositional and thermal structure of the entire Kohistan arc section is constructed using constraints and 209 plutonic whole rock analyses. The aim is to better understand the nature of the chemical differentiation in the plutonic arc crust at different crustal levels. Results indicate that a distinct difference in character exists between the upper and lower plutonic arc crust. Plutonic rocks in the lower crust have whole-rock chemical characteristics that indicate mineral accumulation and residual melt loss. In these cumulate rocks there is a systematic chemical stratification of decreasing incompatible trace elements with depth (e.g. Rb, K2O). In contrast, the plutonic rocks of the upper crust represent mainly frozen liquids and show no systematic relationship between chemical composition and intrusion depth. These results clearly indicate that magmatic differentiation in the Kohistan arc dominantly occurred in the deeper arc crust consistent with the lower crustal ‘hot zone model’. To understand the role of density barriers for melt stagnation in the crust, and thereby for the observed chemical stratification, the detailed density structure of the plutonic arc crust is compared to melt densities calculated for plutonic rocks with near liquid compositions. Results indicate that melts are consistently less dense than rocks, and there is no evidence for a “neutral buoyancy line” controlling melt emplacement. It is speculated that melt stagnation in the lower arc crust and subsequent chemical differentiation of a felsic upper and mafic lower continental crust is dominantly controlled by temperature and to a lesser extent to density or rheological barriers. [Copyright &y& Elsevier]

Highlights: [•] We show DSC data for melting of ice and cyclohexane in silicon dioxide pores. [•] The data show a broad peak at temperatures lower than the bulk melting temperature. [•] We relate the DSC data to pore sizes by the Gibbs–Thompson equation. [•] We show fits of the model equations to DSC data. [•] A single parameter from the fits gives the local surface energy per confined volume. [ABSTRACT FROM AUTHOR]

Abstract: For the geochemical investigation of extraterrestrial surfaces laser-induced breakdown spectroscopy (LIBS) has been suggested as a powerful analytical tool, and is part of the payload on NASA’s rover Curiosity, which reached Mars in August 2012. Apart from soil in general, LIBS is capable of analyzing ice and salts within the soil. This study demonstrates the feasibility of LIBS for investigating and differentiating between different salts by applying three multivariate analysis (MVA) techniques. The focus was on the capability of the MVA techniques for LIBS data to discriminate between sulfates and chlorides with cations of the same kind as pure pressed pellets and in frozen salt solutions. Two data sets of LIBS spectra of eight different salts (CaCl2, CaSO4, KCl, K2SO4, MgCl2, MgSO4, NaCl, Na2SO4), pure and as frozen salt solutions, were acquired in a dedicated simulation chamber under martian atmospheric conditions. With principal components analysis (PCA) both data sets were analyzed with the aim of dividing the spectra of the ices into groups and revealing the most important lines in the spectra for discrimination and identification of the type of salt. PCA performance is improved by selecting the most relevant lines with emphasis on the sulfur and chlorine lines and additionally averaging the spectra before analysis. Moreover, a subsequent PCA with a subset of data can improve the discrimination ability for a sulfate and a chloride with the same type of cation. Soft independent modeling of class analogy (SIMCA) and partial least squares discriminant analysis (PLS-DA) were performed for both data sets. While SIMCA worked well for the pressed salt samples, its application to the spectra of the frozen salt solutions was not successful. A local PLS-DA of the LIBS spectra of salts with the same cation is capable of distinguishing sulfate and chloride. [Copyright &y& Elsevier]

Metallic glasses and their descendants, the so-called bulk metallic glasses (BMGs), can be regarded as frozen liquids with a high resistance to crystallization. The lack of a conventional structure turns them into a material exhibiting near-theoretical strength, low Young''s modulus and large elasticity. These unique mechanical properties can be only obtained when the metallic melts are rapidly cooled to bypass the nucleation and growth of crystals. Most of the commonly known and used processing routes, such as casting, melt spinning or gas atomization, have intrinsic limitations regarding the complexity and dimensions of the geometries. Here, it is shown that selective laser melting (SLM), which is usually used to process conventional metallic alloys and polymers, can be applied to implement complex geometries and components from an Fe-base metallic glass. This approach is in principle viable for a large variety of metallic alloys and paves the way for the novel synthesis of materials and the development of parts with advanced functional and structural properties without limitations in size and intricacy. [Copyright &y& Elsevier]

Abstract: We computed a Lennard-Jones frozen liquid with a free surface using classical molecular dynamics. The structure factor curves on the free surface of this sample were calculated for different depths knowing that we have periodic boundary conditions on the other parts of the sample. The resulting structure factor curves show an horizontal shift of their first peak depending on how deep in the sample the curves are computed. We analyze our resulting curves in the light of spatial correlation functions during melting. The conclusion is that the differences between bulk and surface are quite small during melting and that at the end of melting, only the very surface happens to be less dense than the bulk. This result is intrinsic to the shape of the Lennard-Jones potential and does not depend on any other parameter. [Copyright &y& Elsevier]

We establish the conditions for the frozen path approximation for turbulent transport in a class of nonmixing Gaussian flows with long-range correlation. We identify the regimes of fractional Brownian motion limit as well as the Brownian motion limit. [ABSTRACT FROM AUTHOR]

In previous experiments, we have shown that spaceflight can alter leukocyte and lymphocyte population distributions and mitogen-induced cytokine expression. We hypothesize that these changes are a result of flight-induced physiological and psychological stress. On July 8, 2011, age- and weight-matched, female C57BL/6J mice were placed into Animal Enclosure Modules (AEMs) and flown on the Space Shuttle Atlantis (STS-135) for 13 days ( N = 6–7). Ground controls were housed at the Space Life Science Laboratory (SLSL) at Kennedy Space Center (KSC). Ground AEM control mice were placed into the same hardware used in flight and environmental parameters such as temperature and CO2 levels were matched as closely as possible based on 48 h delayed telemetry data ( N = 12–13). Vivarium control mice were housed in regular shoebox cages ( N = 4). Mice were euthanized and dissected within 3–5 h of landing. Adrenals were removed, snap frozen in liquid N2, and shipped on ice back to Loma Linda University via overnight courier for analysis. Although corticosterone levels were slightly elevated in spaceflight mice, with a corresponding decrease in phosphorylated adrenocorticotropic hormone (ACTH) levels, these changes were not enough to reach significance. Similarly, there were no significant changes in catecholamine levels. This suggests that there is no significant impact of spaceflight on stress pathways. However, closer examination of the data indicates that the circadian rhythm may have masked the overall effect of spaceflight. [ABSTRACT FROM AUTHOR]