Thermal cycling process

Section 4.3), which had to be replenished at every new cycle, the application of heat-stable polymerases from organisms such as Thermus aquations (Taq polymerase), Pyrococcus woesii (Pwo polymerase), Pyrococcus juriosus (Pfu polymerase), or Thermococcus litoralis (Vent polymerase) facilitated automation of the thermal cycling process. 

Figure 14 (A) Schematic of a chip for flow-through PCR. Three well-defined zones are kept at 95, 77, and 60°C by means of thermostated copper blocks. The sample is hydrostatically pumped through a single channel etched into the glass chip. The channel passing through the three temperature zones defines the thermal cycling process. (B) Layout of the device used in the study. The device has three inlets on one side of the device and an outlet on the opposite side. Only two inlets were used, one carrying the sample, the other bringing a constant buffer flow. The chip incorporates 20 identical cycles, except for the first one, which includes a threefold increase in DNA melting time. (Reprinted with permission from Ref. 98.)...

The ability of topoisomerase V to bind and unlink DNA at high temperature makes it extremely useful for thermal cycling processes. In PCR or DNA sequencing topological constraints and strong secondary stmctures in DNA may inhibit normal enzymatic processes. 

Beyond a certain number of cycles there was stabilization in the mechanical properties. After the thermal cycling process was concluded the bars were measured for their Modulus of Rupture using a 3-point bend test method, with a span of 40mm between the suf rts and a crosshead speed of O.Smm/min (Tinius Olsen (Surrey, England) machine, model H25KS). This value of MOR was compared to the value for as-sintered samples. 

Zhang Y, Xia C (2010) A durability model for solid oxide fuel cell electrodes in thermal cycle processes. J Power Sources 195 6611-6618... 

Fig. 4.57. Hysteresis in the course of relative length change Al/l during a thermal cycling process of Zerodur , temperature rate = 1.25 K/min...

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