Tweezers

Particles can be manipulated in suspension using strongly focused laser beams ( optical tweezers ) [25] or magnetic fields [26] and by collecting statistics on tire particle movements using video microscopy, infonnation on the particle interactions can be obtained. 

Grier D G 1997 Optioal tweezers in oolloid and interfaoe soienoe Curr. Op. Coiioid interface Sc/. 2 264-70... 

Nishizaka T, Miyata H, Yoshikawa H, Ishiwata S and Kinosita K 1995 Unbinding force of a single motor molecule of muscle measured using optical tweezers Nature 377 251-4... 

Experimental techniques based on the application of mechanical forces to single molecules in small assemblies have been applied to study the binding properties of biomolecules and their response to external mechanical manipulations. Among such techniques are atomic force microscopy (AFM), optical tweezers, biomembrane force probe, and surface force apparatus experiments (Binning et al., 1986 Block and Svoboda, 1994 Evans et ah, 1995 Israelachvili, 1992). These techniques have inspired us and others (see also the chapters by Eichinger et al. and by Hermans et al. in this volume) to adopt a similar approach for the study of biomolecules by means of computer simulations. 

Kellermayer et aJ., 1997] Kellermayer, M., Smith, S., Granzier, H., and Bustamante, C. Folding-unfolding transition in single titin modules characterized with laser tweezers. Science. 276 (1997) 1112-1116... 

Occasionally an optically inactive sample of tartaric acid was obtained Pasteur noticed that the sodium ammonium salt of optically inactive tartaric acid was a mixture of two mirror image crystal forms With microscope and tweezers Pasteur carefully sep arated the two He found that one kind of crystal (m aqueous solution) was dextrorota tory whereas the mirror image crystals rotated the plane of polarized light an equal amount but were levorotatory... 

Optical storage disks Optical storage media Optical switches Optical trapping Optical tweezers Optical wave guides... 

Germanium [7440-56-4] M 72.6, m 937 , 925-975 , b 2700 , d 5.3. Copper contamination on the surface and in the bulk of single crystals of Ge can be removed by immersion in molten alkali cyanide under N2. The Ge was placed in dry cyanide powder in a graphite holder in a quartz or porcelain boat. The boat was then inserted into a heated furnace which, after a suitable time, was left to cool to room temperature. At 750°, a 1mm thickness requires about Imin, whereas 0.5cm needs about half hour. The boat was removed and the samples were taken out with plastic-coated tweezers, carefully rinsed in hot water and dried in air [Wang J Phys Chem 60 45 7956]. 

Although experimental studies of DNA and RNA structure have revealed the significant structural diversity of oligonucleotides, there are limitations to these approaches. X-ray crystallographic structures are limited to relatively small DNA duplexes, and the crystal lattice can impact the three-dimensional conformation [4]. NMR-based structural studies allow for the determination of structures in solution however, the limited amount of nuclear overhauser effect (NOE) data between nonadjacent stacked basepairs makes the determination of the overall structure of DNA difficult [5]. In addition, nanotechnology-based experiments, such as the use of optical tweezers and atomic force microscopy [6], have revealed that the forces required to distort DNA are relatively small, consistent with the structural heterogeneity observed in both DNA and RNA. 

There shall be no smoking or eating in the weighing area. All filters will be handled with tongs or tweezers. Do not handle the filters with bare hands. 

Molecular Tweezers of Light Take the Measure of a Muscle Fiber s Force... 

Pinzette,/. forceps, tweezers, nippers, pincers. Pionier, m. pioneer (Mil.) engineer, -spreng-mittel, n, engineer explosive. 

Zange, /. (pair of) tongs pincers, nippers, forceps, pliers, tweezers. 

Working carefully with tweezers, Pasteur was able to separate the crystal into two piles, one of "right-handed" crystals and one of "left-handed" crys tals like those shown in Figure 9.6. Although the original sample, a 50 50 mix lure of right and left, was optically inactive, solutions of the crystals from eacl of the sorted piles were optically active, and their specific rotations were equa in amount but opposite in sign. 

Extraction and purification of polynoidin (Nicolas et al., 1982). Specimens of Harmothoe lunulata were collected near Roscoff, Brittany, in France, and were anaesthetized with 0.1 mM tricaine in seawater. The scales were carefully removed with tweezers, and washed several times with seawater to remove tricaine. Then the scales were stored in liquid nitrogen until they were used. 

In 50 mL of perchloroethylene is dissolved 1.5 mL of sebacyl chloride 2.2 g of hexamethylenediamine and 4.0 g of sodium carbonate are dissolved in 50 mL water. The aqueous solution is placed carefully on the perchloroethylene solution in a 200-rnL tail-form beaker or similar vessel (Fig. 3.17). A film is immediately formed at the interface. The film is grasped with tweezers and raised as a rope of continuously forming polymer film. The rope is guided over two glass rods with a 1-mm drop. With this setup, speeds up of 5 m/min can be attained for 8 min. 

This is a case of optically active materials arising from inactive materials. However, it may be argued that an optically active investigator is required to use the tweezers. Perhaps a hypothetical human being constructed entirely of inactive molecules would be unable to tell the difference between left-and right-handed crystals. 

Figure 29, Assembly for micro-ultrafiltration. The tweezers hold the Millipore filter, cut from the strip. The washers are shown be-low the tweezers. In the center, the top and bottom portion of the filter and washer are shown aligned with the Allen screw. An Alien...

The prepared flattened section is inserted into a glass sleeve shaped to fit, and the glass is fused on to the metal, pinched with tweezers and strongly heated. The seal must be carefully annealed. With soft glasses the copper glass interface is coloured red, while with harder glasses the colour is more of a yellowish red. 

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