Working model

Comprehensive Organic Synthesis, Vol. 6, Trost, B.M. Flemming, I. (Eds.), Perga-mon Press, New York, 1991. 

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Fig. 1.1. A fully working model, one- sixth full size, of a steam traction engine of the type used on many forms a hundred years ago. The model con pull on automobile on a few litres of water and a handful of cool. But it is also a nice example of materials selection and design.

Design creates the conceptual solution and development transforms the solution into a fully working model. 

To prove that a particular design of a perpetual motion machine will not work can be vei y time consuming, and the predictable negative result has never been worth the effort. Therefore, the U.S. Patent Office has a policy to not examine applications covering perpetual motion machines unless the applicant furnishes a working model. 

In 1797, Trevithick married Jane Hai vey, lost his father, Richard, Sr., and made his first working models of high pressure engines. His wife was of the established engineering and foundiyi family of Hayle. 

This working model would be the framework for the interpretation of all subsequent biochemical, spectroscopic, and molecular biological studies on this unknown protein. The discovery of a putative [6Fe-6S] protein may have been a surprise to some, but its existence in... 

Fig. 2. Modulation of the RseA activity a working model. In the absence of non-native proteins in the periplasm, is bound to the RseA anti-sigma factor this binding is stabilized by RseB, a co-anti-sigma factor, in the periplasm. Upon accumulation of non-native proteins within the periplasm, RseB is released followed by dissociation of which interacts with RNA polymerase core enzyme to initiate transcription of the heat shock genes of the sigma-E regulon...

Fig. 3. Modulation of the activity of HrcA a working model. It is assumed that HrcA repressor synthesized de novo or dissociated from its operator is present in an inactive form unable to interact with its operator. Through interaction with the GroE chaperone machine, inactive HrcA is converted into its active form...

Simulation is best described as the process of translating a real system into a working model in order to run experiments. A simulation does not duplicate a system rather it is an abstraction of reality using mathematics to express cause-and-effect relationships that determine the behavior of the system. Hence the representation displayed on a computer may not always be pictori-ally similar to the real system, and, if it is, then it must be regarded as an added bonus. Software for computer simulation is often customized and based on that developed in academia. There are not many commercial packages available for pharmaceutical formulation. 

Fig. 1. UV-Vis absorption spectra of the precatalyst Scheme 2. Possible working model for the HKR chiral Co(salen) and monomer and dimer complex. of terminal epoxides catalyzed by C0-AIX3...

Fig. 2. Working model for the tertiary structure of the H -ATPase. See text for details.

Further considerations here do not depend critically on the accuracy of the working model of Fig. 2. Indeed, the interdomain cleft may as well be at the side of the molecule near the surface of the membrane as can be imagined from inspection of the structures proposed by Taylor et al. [75] and Stokes and Green [76] for the Ca -ATPase. It is only important to stipulate that the molecule contains at least two domains and a cluster of membrane-embedded helices. 

State B has the same spectrum as HbCO. This analysis for the TR spectra of Figure 3.35 enables the component difference spectra for the Rdeox Rs> Rt> and T intermediates to be determined and these spectra are shown in Figure 3.37. These difference TR spectra, in conjunction with other data for these intermediates, enables a working model for the allosteric reaction coordinate in the HbCO photocycle to be developed as shown in Figure 3.38 and the reader is referred to reference 156 for details. Photolysis of HbCO (A) results in the geminate state, B, where forces are stored in the heme and these forces subsequently lead to rotation of the E and helices that then breaks the interhelical H-bonds in the Rdeoxy intermediate. These H-bonds become restored in the Rs intermediate and subsequently produce a hinge contact formation in the Rj intermediate that is then followed by formation of the switch contact to result in the T intermediate. ... 

While the working model for the allosteric reaction coordinate for the HbCO photocycle deduced from the TR data is only a partial description of a very complex process, it does provide new insight into this process and demonstrates that there are distinct intermediates along the R to T reaction pathway. ... 

The authors proposed the scheme shown in Figure 3.47 as a working model based on the main products observed in aqueous and non-aqueous solvents. 

The working model for polyenes is essentially one-dimensional, with kinetic energies... 

The implimentation of quantum statistical ensemble theory applied to physically real systems presents the same problems as in the classical case. The fundamental questions of how to define macroscopic equilibrium and how to construct the density matrix remain. The ergodic theory and the hypothesis of equal a priori probabilities again serve to forge some link between the theory and working models. 

At the end of the nineteenth century chemistry was at the cutting edge as a theoretically well-founded experimental science. The most advanced and controversial physical theories of the day had their origin in chemical research, which concerned itself with all aspects related to the nature and constitution of matter. The theories of electrons (sic), atoms and molecules were the working models of practising chemists. Optical activity, like other forms of spectroscopy in its infancy, was the pursuit of analytical chemistry. 

Fry SC, Miller JG. Toward a working model of the growing plant cell wall. Phenolic cross-linking reactions in the primary cell walls of dicotyledons. American Chemical Society, Washington, DC, 1989. 

In the actual (working) model (see Fig. 6.2), the levels become closer as the vibrational number increases. It is this anharmonicity that allows the overtones to exist. The equation describing this phenomenon is... 

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