To test for on target toxicity of a new chemical entity, it is important to have comparable binding affinities of the compound in the target proteins from humans and the test species. To evaluate our myeloid cell leukemia-1 (Mcl-1) inhibitors, we tested them against rodent Mcl-1 and found a significant loss of binding affinity when compared to that seen with human Mcl-1. To understand the affinity loss, we used sequence alignments and structures of human Mcl-1/inhibitor complexes to identify the important differences in the amino acid sequences. One difference is human L246 (F226 in rat, F227 in mouse) in the ligand binding pocket. Mutating rat F226 to a Leu restores affinity, but the mouse F227L mutant still has a ligand affinity that is lower than that of human Mcl-1. Another mutation of mouse F267, located ∼12 Å from the ligand pocket, to the human/rat cysteine, F267C, improved the affinity and combined with F227L resulted in a mutant mouse protein with a binding affinity similar to that of human Mcl-1. To help understand the structural components of the affinity loss, we obtained an X-ray structure of a mouse Mcl-1/inhibitor complex and identified how the residue changes reduced compound complementarity. Finally, we tested Mcl-1 of other preclinical animal models (canine, monkey, rabbit, and ferret) that are identical to humans in terms of these two residues and found that their Mcl-1 bound our compounds with affinities comparable to that of human Mcl-1. These results have implications for understanding ligand selectivity for similar proteins and for the interpretation of preclinical toxicology studies with Mcl-1 inhibitors.

High-entropy alloys (HEAs), such as the Cantor alloy, are considered for various structural applications owing to their excellent corrosion resistance and high strength at low temperatures, typically below −70 °C, including cryogenic conditions. However, during metalworking, introducing stresses and grain refinement can reduce the corrosion resistance of HEAs. Recrystallization heat treatment relieves these stresses and homogenizes the grain structure, thereby restoring their corrosion resistance and physical properties. However, inadequate heat treatment can result in a microstructure in which coarse and refined grains coexist; thus, the corrosion resistance is diminished and the physical properties are compromised. Therefore, a proper heat treatment is essential for achieving the desired corrosion resistance and mechanical properties of HEAs. In this study, a cold-rolled high-entropy Cantor alloy was subjected to heat treatment for various durations, and the conditions were analyzed. The microstructure and electrochemical behavior were examined. The results indicated that the grains coarsened after a heat treatment time of 5 min and the residual stresses decreased for 15 min. The potential increased from −0.20 to −0.09 V, whereas the resistance of the passive layer increased from 39 to 56 kΩ. These findings confirm that in the Cantor alloy, residual stress reduction and recrystallization begin after 5 min of heat treatment at 1100 °C, which contributes to the recovery of corrosion resistance. The corrosion resistance of the Cantor alloy can be effectively controlled through heat treatment. This underscores the importance of optimizing the heat treatment process in the manufacturing of Cantor alloys.

Li-ion batteries are at risk of explosions caused by fires, primarily because of the high energy density of Li ions, which raises the temperature. Battery cases are typically made of plastic, aluminum, or SAF30400. Although plastic and aluminum aid weight reduction, their strength and melting points are low. SAF30400 offers excellent strength and corrosion resistance but suffers from work hardening and low high-temperature strength at 700 °C. Additionally, Ni used for plating has a low current density of 25% international copper alloy standard (ICAS). SAF2507 is suitable for use as a Li-ion battery case material because of its excellent strength and corrosion resistance. However, the heterogeneous microstructure of SAF2507 after casting and processing decreases the corrosion resistance, so it requires solution heat treatment. To address these issues, in this study, SAF2507 (780 MPa, 30%) is solution heat-treated at 1100 °C after casting and coated with Ag (ICAS 108.4%) using physical vapor deposition (PVD). Ag is applied at five different thicknesses: 0.5, 1.0, 1.5, 2.0, and 2.5 μm. The surface conditions and electrochemical properties are then examined for each coating thickness. The results indicate that the PVD-coated surface forms a uniform Ag layer, with electrical conductivity increasing from 1.9% ICAS to 72.3% ICAS depending on the Ag coating thickness. This enhancement in conductivity can improve Li-ion battery safety on charge and use. This result is expected to aid the development of advanced Li-ion battery systems in the future.

Cement is one of the most widely used structural materials and serves as the primary component of concrete. Among the various types, Portland cement is the most commonly utilized due to its excellent strength and corrosion resistance. Recently, efforts have been made to incorporate various functional additives into Portland cement to impart new properties; however, studies on the resulting changes in corrosion resistance remain insufficient. While the existing research has largely focused on impurities in cement, systematic studies on the effects of interstitial elements on the crystallization and electrochemical behavior of cement are scarce. This study investigates the influence of carbon (C) addition on the crystallographic structure and electrochemical properties of Portland cement. C concentrations from 0 to 10 wt.% were added. The microstructure and crystallographic structure with different C concentrations were analyzed using FE-SEM and XRD. The bonding characteristics of cement components according to the C composition were measured using XPS, hardness was measured using Vickers hardness, and electroconductivity was calculated using a 4-point probe. The electrochemical behavior was evaluated according to the ASTM G 61 standards through OCP, EIS, and potentiodynamic polarization tests. As the composition of C increased, the number of voids and cracks decreased, while the electrical conductivity increased from 1.7 × 10⁻⁴ to 4.3 × 10⁻². Additionally, the resistance tended to decrease with the increase in C composition. Therefore, the concentration of C needs to be controlled depending on the required function of the cement.

Portland cement is a critical material widely used in the construction industry, where its crystallization and microstructure are key factors determining its physical and mechanical properties. This study investigated the effect of sulfur on the crystallization and microstructure of Portland cement. Sulfur acts as either an additive or an impurity during the cement production process, influencing the crystal size, distribution, and microstructure formation of major hydration products such as C₃S (tricalcium silicate), C₂S (dicalcium silicate), C₃A (tricalcium aluminate), and C₄AF (tetracalcium aluminoferrite). Through quantitative and qualitative evaluation using XRD, SEM, and EPMA analytical techniques, this study examined changes in the hydration characteristics, crystal structure, and microstructure of Portland cement with varying sulfur concentrations. The results revealed that increased sulfur content promotes the crystal growth of C₃A and the formation of ettringite, which alters the density of the structure during the early stages of hydration and affects its long-term strength properties. These findings suggest that controlling the sulfur content plays a significant role in optimizing the performance and durability of Portland cement. This study highlights the potential for developing high-performance cement by regulating sulfur levels during the production process, contributing to advancements in construction materials.

Portland cement is one of the most widely used construction materials employed in both large-scale structures and everyday applications. Although various materials are often added during production to enhance their performance, NaCl can be introduced in the process for various reasons. Despite this issue, existing studies lack sufficient quantitative data on the effects of NaCl on cement properties. Therefore, this study aims to investigate the physical and chemical degradation mechanisms in cement containing NaCl. Cement specimens were prepared by mixing cement, water, and NaCl, followed by stirring at 60 rpm and curing at room temperature for seven days. Microstructural changes as a function of the NaCl concentration were analyzed using scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Electrochemical properties were evaluated via open-circuit potential (OCP) measurements, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization tests. The results indicate that increasing the NaCl concentration leads to the formation of fine precipitates, the degradation of the cement matrix, and the reduced stability of major hydration products. Furthermore, the electrochemical analysis revealed that higher NaCl concentrations weaken the passive layer on the cement surface, resulting in an increased corrosion rate from 1 × 10⁻⁷ to 4 × 10⁻⁷ on the active polarization of the potentiodynamic polarization curve. Additionally, the pitting potential (E_pit) decreased from 0.73 V to 0.61 V with an increasing NaCl concentration up to 3 wt.%. This study quantitatively evaluates the impact of NaCl on the durability of Portland cement and provides fundamental data to ensure the long-term stability of cement structures in chloride-rich environments.