Field Setup

Use the structure of ofe3-[Co(en)3]3+ from Section 17.4 as a starting structure to build oh3-[Co(tmen)3]3+, and refine it with the original MOMEC force field (Setup Files/Force Field/c momec97 parm). 

In contrast to these near field setups, a near-field interferometer of the Talbot-Lau type, does away with the collimation requirement and accepts spatially incoherent molecular beams. Such a scheme is much more compact, rugged and allows a much higher transmission [Clauser 1992],... 

Error detection should be attempted after a few refinement cycles. Erroneous reference data can frequently be detected by a complete failure of a partially refined force field to fit the data point. On the other hand, such failures are even more frequently a result of deficiencies in the functional form. In any case, the error must be corrected before refinement is finalized, either by removal of the offending reference data or by changes in the functional form of the force field. One can easily identify the data points that are most likely to affect the refinement adversely as the largest weighted contributions to the penalty function. All large deviations must be manually scrutinized to elucidate whether they result from data errors or force field deficiencies. If the latter, it should also be estimated whether a failure to reproduce the data point will adversely affect the intended use of the force field (this is not always the case). If so, the force field setup must be modified before continuing otherwise the data point might simply be removed. 

MD simulations have been employed extensively to study the conformational dynamics of the wild-type PrP for a range of species. A wide variety of force fields, setups, and analyses has been used to this end. The majority of studies is performed on human, mouse, or hamster PrP. In all but a few contributions [53-55], simulations include only the protein portion, i.e., the unglycosylated form without membrane anchoring. These simulations therefore present the recombinant PrP (recPrP) that is used for many in vitro studies, usually produced in Escherichia coli. Often, only the structured part of recPrP is simulated. Although most initial MD studies could only capture local dynamics [40—431. some studies were able to shed light on the misfolding process over short timescales ( 10 ns) [56, 57]. More recent studies reporting multiple simulations of 50 ns or more [58, 59], have provided a more comprehensive view of the conformational dynamics. 

Figure 303. Schematic diagram of the Paducah Phase Ila field setup.

Figure 33.9. Field setup of geoelectrical sounding (Schlumberger method).

Field Setup Anodes and cathodes are installed in separate rows parallel to each other. The design of the field setup is based on the following data and parameters ... 

This method uses the dipole field setup by an oscillating magnetic sample in a uniform magnetic field. The sample oscillation is driven by a loudspeaker that vibrates a sample holder rod, the other end of which moves the sample between the magnet poles. A permanent magnet reference sample is vibrated on the same rod. Separate induction coils, oriented with their axes parallel to the vibration monitor to allow phase-sensitive detection, monitor the sample and reference. Only a relatively small sample can be placed fully within a uniform field, but measurements on small single crystals are readily made with this apparatus. Measurements on anisotropic crystals can be made by remounting the crystal to vary the orientation with respect to the sample rod. 

Figure 5.10 Four-pin soil resistivity measurements being made (a) field setup and (b) close-up on the instrument. (Courtesy of Tinker Rasor)...

Photodiodes convert photons into electrical current and are used as power sources as well as photodetectors. Recall that the internal fields setup in the depletion region sweep holes toward the p-region and electrons toward the n-region. Photons above the energy gap absorbed in or near the depletion region produce the electron-hole pairs, which are swept... 

Up into continuous lines of nanodroplets at the lowest fiber diameters. A further consideration of near-field electrospinning is that some physical effects observed in the standard electrospinning differ from the near-field setup, for example, a drop in the electric field strength results in decreased fiber diameter. Chang et al. (2008) describe some of these observed differences however, further research is required to characterize the process completely. 

A scheme of a wide-field miaoscope setup is given in Figure 5 and the basic components (except for the detector) are nearly identical to those in confocal miaoscopy. A wide-field setup consists of an excitation source, an inverted miaoscope, a sensitive 2D auay detector, and elearonics for image acquisition. 

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