The ceramic injection molding technique was used in the gas-pressure sintering of ultra-fine Si3N4 powder. The feedstock＇s flowability, debinding rate, defect evolution, and microstructural evolution during productio...The ceramic injection molding technique was used in the gas-pressure sintering of ultra-fine Si3N4 powder. The feedstock＇s flowability, debinding rate, defect evolution, and microstructural evolution during production were explored. The results show that the solid volume loading of less than 50vol% and the surfactant mass fraction of 6wt% result in a perfect flowability of feedstock; this feedstock is suitable for injection molding. When the debinding time is 8 h at 40°C, approximately 50% of the wax can be solvent debinded. Defects detected during the preparation are traced to improper injection parameters, mold design, debinding parameters, residual stress, or inhomogeneous composition distribution in the green body. The bulk density, Vickers hardness, and fracture toughness of the gas-pressure-sintered Si3N4 ceramic reach 3.2 g/cm^3, 16.5 GPa, and 7.2 MPa·m^1/2, respectively.展开更多
Effective therapies are urgently needed to stabilize patients with marginally compressible junctional hemorrhage long enough to get them to the hospital alive.Herein,we report injectable and rapidly expandable cryogel...Effective therapies are urgently needed to stabilize patients with marginally compressible junctional hemorrhage long enough to get them to the hospital alive.Herein,we report injectable and rapidly expandable cryogels consisting of polyacrylamide and thrombin(AT cryogels)created by cryo-polymerization for the efficient management of lethal junctional hemorrhage in swine.The produced cryogels have small pore sizes and highly interconnected porous architecture with robust mechanical strength.The cryogels exhibit rapid shape memory properties and prove to be resilient against fatigue.These cryogels also show high water/blood absorption capacity,fast blood clotting effect,and enhanced adhesion of red blood cells and platelets in vitro.Further,in vivo,hemostatic efficacy tests in a lethal swine junctional hemorrhage model suggest that treatment with AT cryogels,especially AT-2 cryogels,achieves the least blood loss and the highest survival rate(100%)compared to currently employed products such as XStat®and combat gauze.The high hemostatic performance of the cryogels may be attributed to highly interconnected porous architecture with small pore size and the use of thrombin as a pro-coagulant agent.Collectively,injectable and rapidly expandable thrombin-decorated polyacrylamide-based cryogels show significant promise as hemostatic material,offering effective management of marginally compressible junctional hemorrhages in prehospital settings.展开更多
基金financially supported by the National Nature Science Foundation of China (Nos. 51102024 and 21276028)
文摘The ceramic injection molding technique was used in the gas-pressure sintering of ultra-fine Si3N4 powder. The feedstock＇s flowability, debinding rate, defect evolution, and microstructural evolution during production were explored. The results show that the solid volume loading of less than 50vol% and the surfactant mass fraction of 6wt% result in a perfect flowability of feedstock; this feedstock is suitable for injection molding. When the debinding time is 8 h at 40°C, approximately 50% of the wax can be solvent debinded. Defects detected during the preparation are traced to improper injection parameters, mold design, debinding parameters, residual stress, or inhomogeneous composition distribution in the green body. The bulk density, Vickers hardness, and fracture toughness of the gas-pressure-sintered Si3N4 ceramic reach 3.2 g/cm^3, 16.5 GPa, and 7.2 MPa·m^1/2, respectively.
基金supported by startup funds from the University of Nebraska Medical Center(UNMC)and Congressionally Directed Medical Research Program(CDMRP)/Peer Reviewed Medical Research Program(PRMRP)FY19 W81XWH2010207 to J.X.M.A.C.We thank the Proteomics&Metabolomics Facility(RRID:SCR_021314),Nebraska Center for Biotechnology at the University of Nebraska-Lincoln for the mass spectrometry analysis.The facility and instrumentation are supported by the Nebraska Research Initiative.
文摘Effective therapies are urgently needed to stabilize patients with marginally compressible junctional hemorrhage long enough to get them to the hospital alive.Herein,we report injectable and rapidly expandable cryogels consisting of polyacrylamide and thrombin(AT cryogels)created by cryo-polymerization for the efficient management of lethal junctional hemorrhage in swine.The produced cryogels have small pore sizes and highly interconnected porous architecture with robust mechanical strength.The cryogels exhibit rapid shape memory properties and prove to be resilient against fatigue.These cryogels also show high water/blood absorption capacity,fast blood clotting effect,and enhanced adhesion of red blood cells and platelets in vitro.Further,in vivo,hemostatic efficacy tests in a lethal swine junctional hemorrhage model suggest that treatment with AT cryogels,especially AT-2 cryogels,achieves the least blood loss and the highest survival rate(100%)compared to currently employed products such as XStat®and combat gauze.The high hemostatic performance of the cryogels may be attributed to highly interconnected porous architecture with small pore size and the use of thrombin as a pro-coagulant agent.Collectively,injectable and rapidly expandable thrombin-decorated polyacrylamide-based cryogels show significant promise as hemostatic material,offering effective management of marginally compressible junctional hemorrhages in prehospital settings.
