In this study a combined analysis of osmotic injury and cytotoxic effect useful for the optimization of the cryopreservation process of a cell suspension is carried out. The case of human Mesenchymal Stem Cells (hMSCs) from Umbilical Cord Blood (UCB) in contact with dimethyl sulfoxide (DMSO) acting as Cryo‐Protectant Agent (CPA) is investigated from the experimental as well as the theoretical perspective. The experimental runs are conducted by suspending the cells in hypertonic solutions of DMSO at varying osmolality, system temperature, and contact times; then, at room temperature, cells are pelleted by centrifugation and suspended back to isotonic conditions. Eventually, cell count and viability are measured by means of a Coulter counter and flow‐cytometer, respectively. Overall, a decrease in cell count and viability results when DMSO concentration, temperature, and contact time increase. A novel mathematical model is developed and proposed to interpret measured data by dividing the cell population between viable and nonviable cells. The decrease of cell count is ascribed exclusively to the osmotic injury caused by expansion lysis: excessive swelling causes the burst of both viable as well as nonviable cells. On the other hand, the reduction of cell viability is ascribed only to cytotoxicity which gradually transforms viable cells into nonviable ones. A chemical reaction engineering approach is adopted to describe the dynamics of both phenomena: by following the kinetics of two chemical reactions during cell osmosis inside a closed system it is shown that the simultaneous reduction of cell count and viability may be successfully interpreted. The use of the Surface Area Regulation (SAR) model recently proposed by the authors allows one to avoid the setting in advance of fixed cell Osmotic Tolerance Limits (OTLs), as traditionally done in cryopreservation literature to circumvent the mathematical simulation of osmotic injury. Comparisons between experimental data and theoretical simulations are provided: first, a nonlinear regression analysis is performed to evaluate unknown model parameters through a best‐fitting procedure carried out in a sequential fashion; then, the proposed model is validated by full predictions of system behavior measured at operating conditions different from those used during the best‐fit procedure.

Liquid metals and metallic alloys often exist as metastable phases or can be undercooled below their equilibrium melting point. The Traditional CALPHAD (CALculation of PHAse Diagrams) approach struggles to accurately model these metastable conditions, which are important in rapid quenching techniques like additive manufacturing, and to understand glass formation or oxidation phenomena occurring in the liquid phase during nuclear and high-temperature aerospace applications. On the contrary, the third-generation CALPHAD models have the potential to accurately describe metastable phase diagrams to provide better predictions of molten phase behavior under non-equilibrium conditions. The latter approach is utilized in this study to achieve a more accurate description of the thermodynamic properties of elemental Nb and Zr, with a particular focus on their liquid phases. By incorporating available first-principles data, the representation of the liquid state is improved for both elements, capturing the peculiar behavior of the heat capacity in a wide temperature range. These improvements enable a more reliable prediction of phase stability and liquidus boundaries in the Nb-Zr system. A partial re-assessment of the Nb-Zr binary phase diagram is also conducted with refined predictions of liquidus boundaries that align well with experimental data.

The paper discusses the impact of cell size on cytotoxicity and expansion lysis during the osmotic excursions resulting from the contact of hMSCs from UCB with Me2SO. It builds upon the mathematical model recently presented by the authors, which pertains to a population of cells with uniform size. The objective is to enhance the model's relevance by incorporating the more realistic scenario of cell size distribution, utilizing a Population Balance Equations approach. The study compares the capability of the multiple-sized model to the single-sized one to describe system behavior experimentally measured through cytofluorimetry and Coulter counter when, first, suspending hMSCs in hypertonic solutions of Me2SO (at varying osmolality, system temperature, and contact times), and then (at room temperature) pelleting by centrifugation before suspending the cells back to isotonic conditions. Simulations demonstrate that expansion lysis and cytotoxic effect are not affected by cell size for the specific system hMSCs/Me2SO, thus confirming what was found so far by the authors through a single-size model. On the other hand, simulations show that, when varying the adjustable parameters of the model that are expected to change from cell to cell lineages, expansion lysis is sensitive to cell size, while cytotoxicity is not, being mainly influenced by external CPA concentration and contact duration. More specifically, it is found that smaller cells suffer expansion lysis more than larger ones. The findings suggest that different cells from hMSCs may require a multiple-sized model to assess cell damage during osmotic excursions in cryopreservation.

In situ resource utilization (ISRU) and in situ fabrication and repair (ISFR) are critical research and technological paradigms for future space exploration. They aim to reduce reliance on Earth-supplied materials by utilizing resources available on celestial bodies, while enabling on-site fabrication and repair through the use and processing of local resources. ISRU and ISFR are strongly interconnected, with the shared objective of enabling more sustainable and autonomous long-duration missions to the Moon, Mars, and beyond. This work presents a comprehensive and critical review of scientific and patent literature published primarily between 2010 and 2025, complemented by selected earlier seminal contributions for context. The analysis provides an integrated perspective on major technological developments, key challenges, and emerging research directions in low-gravity and microgravity environments.