Unwind

All of the steps from the unwinding of the original DNA double helix to the super coiling of the new DNAs are catalyzed by enzymes... 

The two strands begin to unwind Each strand will become a template for construction of its complement... 

As the strands unwind the pyrimidine and purine bases become exposed Notice that the bases are exposed m the 3 — 5 direction in one strand and m the 5 — 3 direction m the other... 

Fig. 9. Extmsion coating A, unwinding of substrate B, pressure roU C, chill roU D, die E, stripper roU F, edge trimmer and G, windup of coated...

Fig. 11. Wke-coatiag line A, unwinding of wine (payoff) B, stiaightenei C, pieheatei D, extrudei E, watei trough F, tester G, capstan (puUer) and H,...

Measuring rollers unwind and measure the precise length of packaging material at constant velocity. 

Vinyl backed packaging tapes are quite popular in Europe. The vinyl backing is commonly manufactured using a calendering process. Printability and smooth unwind of the tape rolls are amongst the desirable features of these tapes. 

Release coatings are important components of pressure sensitive adhesive (PSA) products such as tapes and labels [1]. Release materials are coated onto the backside of PSA tape backings (often called low adhesion backsizes or LABs in this form) to provide the desired tape roll unwind force. They are also coated onto various substrates to form release liners for PSA products such as labels and transfer tapes. Typically the thickness of the release coating is less than 1 p,m, and often times less than 0.1 jLm. Release coatings can be thought of as the PSA delivery system, providing a controlled unwind or release force and protecting the adhesive from contamination and unintentional contact until it is applied. 

Some additional requirements of the release coating may include the ability to write, print, or paint onto it, to provide quiet or smooth unwind, or to exhibit low coefficient of friction. There is also a trend towards the use of solventless release materials in the form of waterbased or 100% solids coatings. 

Figure 12.16), can insert between the stacked base pairs of DNA. The bases are forced apart to accommodate these so-called intercalating agents, causing an unwinding of the helix to a more ladderlike structure. The deoxyribose-phosphate backbone is almost fully extended as successive base pairs are displaced 0.7 nm from one another, and the rotational angle about the helix axis between adjacent base pairs is reduced from 36° to 10°. 

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