From a Poincar�� plot, two non-linear parameters SD1 and SD2 can be calculated :SD1=12Var(xn+1?xx)(1)SD2=2SDNN2?12SD12(2)where selleck chem x represents the HHI or RRI sequences, symbol Var is the variance of the differences in successive RRI or HHI, SDNN is the standard deviation of the RRIs or HHIs. SD1 represents short Inhibitors,Modulators,Libraries term beat-to-beat variability of the data and SD2 is long term beat-to-beat variability.3.3. Statistical AnalysisTo assess how similar HRV parameters derived from heartbeat compared with those derived from the ECG, one-way ANOVA wa
The variation of viscoelastic properties of a polymer material during its crystallization is important information in the design of a variety of polymer processing equipments.
For instance, the property change has a key role in the design of a mold for an injection molding machine, but the property measurement is difficult while the polymer crystallizes.A quartz crystal resonator is composed of a thin quartz crystal sandwiched between two metal electrodes that establish an alternating Inhibitors,Modulators,Libraries electric field across the crystal, causing vibrational motion of the crystal. The motion is characterized with the resonant frequency and admittance of the resonator, and the characteristic is sensitive to the changes of mass and physical property of an overlayer on its electrode. Because the resonator is so sensitive, it can sense a variety of changes in micro-scale at the electrode interface. In polymerization, the rheological properties of a reactant and product mixture vary continuously as the polymerization Inhibitors,Modulators,Libraries proceeds.
The resonator has been implemented in the monitoring of a UV photopolymerization by measuring its resonant resistance . The nucleation and crystal formation in a cooling crystallization have also been investigated Inhibitors,Modulators,Libraries with the quartz crystal resonator [2,3].The resonant frequency and admittance of the resonator can be interpreted to the changes of mass and viscoelasticity of an overlayer at its electrode interface. Reed et al.  presented a physical description of a viscoelastically loaded resonator for either very thick viscous fluids or very thin elastic overlayers. Buttry and Ward  gave an extensive review of the quart crystal resonator including basic principles of an AT-cut resonator and relation of the mechanical system composed of a spring, mass and a damper to the electrical circuit of resistance, inductance and capacitance.
Nwankwo and Durning  provided an impedance analysis of the resonator for very thick viscoelastic fluids. Kim et al.  demonstrated the applicability of a specially designed GSK-3 resonator system to monitor the change of viscoelastic property of thin polymer films selleck bio subjected to temperature variation. When a PMMA/PVAc blend was coated on the one side of the resonator, the resonant frequency decreased accompanying hysteresis with the increased temperature.