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3D printing of a flexible polyurethane elastomer is highly demandable for its potential to revolutionize industries ranging from footwear to soft robotics thanks to its exceptional design flexibility and elasticity performance. Nevertheless, conventional methods like fused deposition modeling (FDM) and vat photopolymerization (VPP) polyurethane 3D printing typically limit material options to thermoplastic or photocurable polyurethanes. In this research, a water-borne polyurethane ink was synthesized for direct ink writing (DIW) 3D printing through the incorporation of cellulose nanofibrils (CNFs), enabling direct printing of complex, monolithic elastomeric structures at room temperature that can maintain the designed structure. Additionally, a solvent-induced fast solidification (SIFS) method was introduced to facilitate room-temperature curing and enhance mechanical properties. The 3D-printed WPU structures demonstrated strong interfacial adhesion, exhibiting high ultimate tensile strength of up to 22 MPa and an elongation at break of 951%. The 3D-printed WPU structures also demonstrated outstanding resilience and durability, capable of enduring more than 100 cycles of compression and tension as well as withstanding vehicle crushing and heavy lifting. This method also shows suitability for 3D printing complex structures such as a vase and an octopus.

Intraorbital arteriovenous fistula is a rare vascular disease characterized by an acquired arteriovenous communication without direct cavernous sinus involvement. Intraorbital arteriovenous fistula may develop slowly and present similarly to other insidious orbitopathies, such as carotid-cavernous fistula. The authors present a case of a superficial temporal artery to superior ophthalmic vein fistula arising in the absence of trauma or prior surgery. This is the first report of a spontaneous intraorbital arteriovenous fistula arising between these vessels and further describes the rare occurrence of intraorbital arteriovenous fistula.The authors report a case of spontaneous superficial temporal artery to superior ophthalmic vein fistula with slowly progressive proptosis treated with embolization.