Beacons

A highly active form of manganese dioxide is available from Beacon Chemical Industries, Inc., 33 Richdale Ave., Cambridge, Mass. 02140. 

Incorporation of fluorine into a biological substrate opens a spectral window for viewmg biomolecular structure and dynamics in solution With mmimal background mletference, fluonne NMR can provide clear spectral information for fluorme conlainmg macromolecules, in contrast to an indecipherable mass of signals from proton or carbon NMR Whether the fluonnated unit is termed a probe, tag, marker, or reporter group, its function is the same to act as a beacon of spectral information... 

Feuer, n. fire furnace, hearth, forge light (as for a signal), beacon. 

Lear, L., ed. (1998). Lost Woods The Discovered Writing of Rachel Carson. Boston Beacon Press. 

Daly, H., and Cobb, J. (1989). For the Common Good. Boston Beacon Press. 

Trimethylamine oxide is normally available as a hydrate, and for the present preparation it is necessary to convert it to its anhydrous form. A convenient way of doing this is as follows. A solution of 45.0 g. of trimethylamine oxide dihydrate (supplied by Beacon Chemicals) is dissolved in 300 ml. of warm dimethyl-formamide and placed in a three-necked flask set up for distillation. At atmospheric pressure the flask is heated and solvent distilled off until the boiling point reaches 152-153°. Then the pressure is reduced using a water aspirator, and the remainder of the solvent is distilled. At the end of the distillation the temperature of the bath is slowly raised to 120°. The residual anhydrous trimethylamine oxide (30 g.) can be dissolved in 100 ml. of chloroform and may remain in the same flask for use in the present preparation. 

In order to overcome the requirement of having a bright "natural guide star" (NGS) near an astronomical source, a first generation of laser guide stars (LGS), or laser beacons, has been deployed to produce bright artificial stars from which wavefront distortions can be assessed. LGSs consist of the... 

There are several factors to consider when using a LGS. First, beacons are formed within the earth s atmosphere, near the telescope aperture. As a result, they don t sample the full telescope aperture when focused on object at infin-... 

The power required for a Rayleigh LGS is al00 W per beacon. The trade off between increasing AH to increase the return flux and decreasing it to decrease the spot size, which increases SNR, is given by ... 

Theoretical level populations. Sinee there are population variations on time seale shorter than some level lifetimes, a complete description of the excitation has been modeled solving optical Bloch equations Beacon model, Bellenger, 2002) at CEA. The model has been compared with a laboratory experiment set up at CEA/Saclay (Eig. 21). The reasonable discrepancy when both beams at 589 and 569 nm are phase modulated is very likely to spectral jitter, which is not modeled velocity classes of Na atoms excited at the intermediate level cannot be excited to the uppermost level because the spectral profile of the 569 nm beam does not match the peaks of that of the 589 nm beam. 

Figure 23. Return flux 330nm Measurements at Pierrelatte versus Beacon model ( Bellenger, 2002).

The three main categories of hybridization probes for real-time PCR are (1) cleavage based assays such as TaqMan, (2) displaceable probe assays such as Molecular Beacons and (3) probes which are incorporated directly into primers such as Scorpions. 

Hall, Alfred Rupert. The Scientific Revolution 1500-1800. 2nd ed ed. Boston (MA) Beacon P, 1962. 

Real-time PCR is a quantitative method for measuring amplicons as they are produced by measuring the increase in fluorescence of a dye added to the reaction mixture.12,104,105 Methods using fluorescent reporters, such as SYBR Green,104,106 TaqMan ,107,108 or molecular beacons,9 collect quantitative data at the time when DNA is in the exponential phase of amplification. 

Fortin, N. Y. Mulchandani, A. Chen, W. Use of real-time polymerase chain reaction and molecular beacons for the detection of Escherichia coli 0157 H7. Anal. Biochem. 2001, 289, 281-288. 

Tyagi S, Kramer FR (1996) Molecular beacons probes that fluoresce upon hybridization. Nat Biotechnol 14 303-308... 

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