Unwinding lines

F. 4.4 Unwinding lines in a SmC sample with a antiparallel and b parallel planar anchoring conditions on the upper and lower substrate. The local director of the SmC phase is represented by a nail. The s5onbols 9 and O correspond to cross sections of +2ti and -2ti disclinations (redrawn after [11])... 

F. 5.32 Striped texture of the lyotropic SmC analog phase in a sample of C50 with a 59 wt% of water at 36 °C and b 32 wt% of formamide at 30 °C. Due to the occurrence of unwinding lines, the pitch p corresponds to the distance between two stripes instead of only one (adapted from [20], Copyright 2013 Wiley-VCH Verlag GmbH Co. KGaA, Weinheim. Reproduced with permission.)... 

Focal conic domains also appear in smectic C phases. Their structure was extensively studied, especially in the ferroelectric SmC materials, where, due to competition between the imiform surface anchoring and the helical structure inside the bulk, periodic arrays of defect lines (so-called unwinding lines) form (Figure 6.12) near the surfaces. The distance between the lines... 

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,...

Figure 28.4 A representation of semiconservative DNA replication. The original double-stranded DNA partially unwinds, bases are exposed, nucleotides line up on each strand in a complementary manner, and two new strands begin to grow. Both strands are synthesized in the same 5 - 3 direction, one continuously and one in fragments.

E Transcription is the process by which RNA is produced to carry genetic information from the nucleus to the ribosomes. A short segment of the DNA double helix unwinds, and complementary ribonucleotides line up to pro-... 

Figure 2(b) represents the potential surface of the identical system, mapped onto the double-cover space [28], The latter is obtained simply by unwinding the encirclement angle < ), from 0 2ti to 0 4ti, such that two (internal) rotations around the Cl are represented as one in the page. The potential is therefore symmetric under the operation Rin defined as an internal rotation by 2n in the double space. To map back onto the single space, one cuts out a 271-wide sector from the double space. This is taken to be the 0 2ti sector in Fig. 2(b), but any 27i-wide sector would be acceptable. Which particular sector has been taken is represented by a cut line in the single space, so in Fig. 2(b) the cut line passes between < ) = 0 and 2n. Since the single space is the physical space, any observable obtained from the total (electronic + nuclear) wave function in this space must be independent of the position of the cut line. 

Fig. 10 Extrusion coating line. 1 Extrusion, 2 unwinding, 3 pretreatment, thickness measurement, temperature control, 4 laminator system, 5 thickness measurement, second pretreatment, 6 winder). (Reproduced with permission from Reifenhauser)...

Replication of DNA is an enzymatic process that starts with the partial unwinding of the double helix. Just before the cell division, the double strand begins to unwind. As the strands separate and bases are exposed, new nucleotides line up on each strand in a complementary fashion, A to T, and C to G. Two new strands now begin to grow, which are complementary to their old template strands. Two new identical DNA double helices are produced in this way, and these two new molecules can then be passed on, one to each daughter cell. As each of the new DNA molecules contains one strand of old DNA, and one new, the process is called semiconservative replication. 

T FIGURE 24.19 DNA replication. A portion of the DNA double helix unwinds, and complementary nucleotides line up for linking to yield two new DNA molecules. Each of the new DNA molecules contains one of the original strands and one new strand. 

The genetic instructions contained in DNA are transcribed into RNA when a small portion of the DNA double helix unwinds and one of the two DNA strands acts as a template for complementary ribonucleotides to line up, a process similar to that of DNA replication (Figure 24.20). The only difference is that uracil (U) rather than thymine lines up opposite adenine. Once completed, the RNA molecule separates from the DNA template, and the DNA rewinds to its stable doublehelix conformation. 

Fig. 22.1. A model of gene silencing. Long, double-stranded RNAs (dsRNAs) are processed into 20-26 nucleotide small interfering RNAs (siRNAs) by Dicer (Step 1). The siRNAs associate with an RNA-induced silencing complex (RISC, Step 2), unwinding and activating in the process (Step 3). The antisense strand of the siRNA guides the RISC to complementary mRNA molecules (Step 4), which are cleaved and destroyed (Step 5). Sense and antisense RNA strands are indicated by thick and thin lines, respectively.

When you have wound a reasonable quantity of polymer break the rope with the forceps and submerge the polymer that you have collected on the rod into a beaker of acetone or alcohol. You can unwind the rope with the forceps (do not handle with your bare hands yet) to make better contact with the wash solvent. Leave the polymer in the solvent for at least an hour, or better, overnight. Remove, rinse with a little fresh solvent, then with watei and dry. At this point the nylon should have absolutely no odor and is safe to handle with your bare hands. Examine the properties of a small length of your sample. Is it strong Does it resemble nylon fishing line ... 

From unwind to rewind rolls, there are a number of rolls over which uncoated and coated substrates travel. They are necessary to guide the web at an accurate position through the line. The rolls are running in ball or other type bearings that are precision ground. They must be kept clean and accurately fitted into the line on sturdy frames. They are kept in a perfect alignment in the line. When the substrate is a very light or a smooth material, it is frequently necessary for several of the rolls to be driven. For paper however, most auxiliary rolls are idlers. 

Figure 18.3 is an extrusion line schematic drawing of tension control equipment for the unwinding substrate. The arrows indicate the motions of the driven tension control rolls and idlers as well as the substrate, and the direction of outward pressure-on the rolls. Figure 18.4 is what is called a flying splice on a double-station-unrolling stand where ... 

Preheater Roll As an example in a coating line a heated roll is installed between a pressure roll and unwind roll. Purpose is to heat the substrate prior to being coated. 

Rothmund-Thomson (Recql 4) proteins. The genes that encode these proteins are altered in human syndromes of the same name. Patients with these diseases are predisposed to different forms of cancer. Cell lines derived from patients with these diseases exhibit chromosome instability and accumulate abnormal replication intermediates. When these helicase proteins are studied in vitro, they can unwind Holliday junction-like structures. A characteristic of many proteins involved in homologous recombination is that they can be visualized as forming subnuclear structures in cells in response to DNA damage. This can be directly visualized using immunofluorescence and the structures that are formed are called foci (see Section 23.8.2). 

Replication of DNA la the process by whkh identical DNA copies arc made and genetic infonnatioit U preserved- This occura when the [>NA douUe helix unwinds, complementaiy deoxyribonurleoiides line up in order, and two new DNA molecules are produced. 

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