Stannsoporfin

Given that electronic components often undergo intricate thermal and mechanical loads during operation, comprehensively understanding lead-free solder, particularly solder based on [Formula: see text]-Sn, in various complex load conditions, plays a crucial role in ensuring the structural integrity and functional reliability of integrated circuits. Therefore, investigating the mechanical properties and fracture behavior of [Formula: see text]-Sn as a solder material holds paramount importance. In this study, we performed molecular dynamics simulations using the modified embedded atom method to investigate the mechanical properties and crack propagation of single-crystal [Formula: see text]-Sn under different strain rates. The research findings demonstrate that as the strain rate increases, the single-crystal [Formula: see text]-Sn exhibits elevated yield strength, fracture strength, and strain, while the elastic modulus decreases. Under higher strain rates, the relationship between dislocation density and strain rate in single-crystal [Formula: see text]-Sn is quantitatively elucidated. The substantial increase in internal dislocation density imparts conspicuous strain hardening to the material, rendering plastic deformation more challenging. This observation sheds light on the microscale mechanism of strain hardening at the atomic level. Our results shall facilitate a deeper investigation into the mechanical behavior of single-crystal [Formula: see text]-Sn while also paving the path for optimizing the design and application of lead-free solder materials in the electronics industry.

Warm ischemia time (WIT) and ischemia–reperfusion injury are limiting factors for vascularized composite allograft (VCA) transplantation. Subnormothermic machine perfusion (SNMP) has demonstrated the potential to extend WIT in organ transplantation. This study evaluates the effect of SNMP on VCA viability after prolonged WIT.

Rat hindlimbs underwent WIT for 30, 45, 60, 120, 150, or 210 min, followed by 3-h SNMP. Monitoring of perfusion parameters and outflow determined the maximum WIT compatible with limb viability after SNMP. Thereafter, 2 groups were assessed: a control group with inbred transplantation (Txp) after 120 min of WIT and an experimental group that underwent WIT + SNMP + Txp. Graft appearance, blood gas, cytokine levels, and histology were assessed for 21 d.

Based on potassium levels, the limit of WIT compatible with limb viability after SNMP is 120 min. Before this limit, SNMP reduces potassium and lactate levels of WIT grafts to the same level as fresh grafts. In vivo, the control group presented 80% graft necrosis, whereas the experimental group showed no necrosis, had better healing (P = 0.0004), and reduced histological muscle injury (P = 0.012). Results of blood analysis revealed lower lactate, potassium levels, and calcium levels (P = 0.048) in the experimental group. Both groups presented an increase in interleukin (IL)-10 and IL-1b/IL-1F2 with a return to baseline after 7 to 14 d.

Our study establishes the limit of WIT compatible with VCA viability and demonstrates the effectiveness of SNMP in restoring a graft after WIT ex vivo and in vivo, locally and systemically.