Comparative Study of Single Opening&Closing and Continuous Pulsatile Flow Valve Tester.

Purpose: The purpose is to demonstrate the difference in closing volume fraction between the single opening&closing valve tester (SOCVT) and continuous pulsatile flow valve tester (CPFVT).

Methods: A comparative study was conducted in four hemodynamic conditions selected from the ISO 5840 on the four mitral valve states: normal annulus, 40% annulus dilation, 60% annulus dilation, and repaired valve with a clip device in both the SOCVT and CPFVT. The closing volume fractions were compared and errors calculated in the 16 cases.

A Single-opening&closing Valve Tester for Direct Measurement of Closing Volume of the Heart Valve.

Purpose: The objective of this study was to develop a novel single opening&closing pulsatile flow in-vitro valve tester for direct measurement of closing volume of the heart valve.

Methods: A single opening&closing valve tester was composed of a piston pump, valve mounting chamber, reservoir, measurement and control system. The piston pump was used to drive a valve to open and close with dictated flow which comprised three phases of accelerated, constant, and decelerated flow with six slopes.

Thermo-responsive and compression properties of TEMPO-oxidized cellulose nanofiber-modified PNIPAm hydrogels.

In this study, TEMPO-oxidized bamboo cellulose nanofibers (TO-CNF) with anionic carboxylate groups on the surfaces were in-situ incorporated into poly(N-isopropylacrylamide) (PNIPAm) matrix to improve its thermo-responsive and mechanical properties during the polymerization. The microstructure, swelling behaviors, and compressive strength of resultant PNIPAm composite hydrogels with varying contents of TO-CNFs (0-10wt%) were then examined, respectively. Modified hydrogels exhibited the similar light transparency to pure PNIPAm one due to the formation of semi-IPN structure between PNIPAm and TO-CNF.