Tchen

Kumar, A., Tchen, P., Roullet, F., and Cohen, J. (1988) Nonradioactive labeling of synthetic oligonucleotide probes with terminal deoxynucleotidyl transferase. Anal. Biochem. 169, 376-382. 

Analysis of the details of the pathway was helped by the discovery by Nancy Bucher (1953) that cholesterol synthesis took place in cell-free post-mitochondrial supernatants. ATP, Mg2+ and NAD+ were required. Tchen and Bloch extended these findings to show that squalene could be formed anaerobically but the conversion of squalene to cholesterol was oxygen dependent, the oxygen of the intermediate lanosterol being derived from 8C>2 not H2180. It therefore became possible to focus either on the conversion of acetate to squalene or on the latter s cyclization to the sterol. 

A variety of statistical models are available for predictions of multiphase turbulent flows [85]. A large number of the application oriented investigations are based on the Eulerian description utilizing turbulence closures for both the dispersed and the carrier phases. The closure schemes for the carrier phase are mostly limited to Boussinesq type approximations in conjunction with modified forms of the conventional k-e model [87]. The models for the dispersed phase are typically via the Hinze-Tchen algebraic relation [88] which relates the eddy viscosity of the dispersed phase to that of the carrier phase. While the simplicity of this model has promoted its use, its nonuniversality has been widely recognized [88]. 

Cox (C5) and Tchen (Tl) also obtained expressions for the drag on slender cylinders and ellipsoids which are curved to form rings or half circles. The advantages of prolate spheroidal coordinates in dealing with slender bodies have been demonstrated by Tuck (T2). Batchelor (Bl) has generalized the slender body approach to particles which are not axisymmetric and Clarke (C2) has applied it to twisted particles by considering a surface distribution rather than a line distribution. 

The second general approach is based on extension of the creeping flow result, as in earlier sections. Corrsin and Lumley s modification (Cll) of the equation proposed by Tchen (Tl) allows Eq. (11-43) to be generalized as... 

The minus sign indicates that the force is in the opposite direction of the pressure gradient [Tchen, 1947]. The significance of this force is evident, for example, when a shock wave propagates through a gas-solid suspension. 

Tchen, C. M. (1947). Mean Value and Correlation Problems Connected with the Motion of Small Particles in a Turbulent Field. Ph.D. Dissertation. Delft University, Netherlands. 

Here we present the derivation of the transport coefficients due to diffusion of discrete particles in a homogeneous turbulent flow. Although the Hinze-Tchen model was developed in a more general form for general particle-fluid multiphase flows, we introduce this model only for the cases of gas-solid flows. Some assumptions for this model are the following ... 

The dynamic behavior of discrete particles in turbulence can be described by the BBO equation [Basset, 1888 Boussinesq, 1903 and Oseen, 1927] for the slow motion of a spherical particle in a fluid at rest. This equation was extended by Tchen (1947) to the case of a fluid moving with time-dependent velocity as... 

For the Reynolds number range typical of drag reduction (Re 105), / is about 0.02 from the Moody chart (see Fig. 11.7). The typical turbulent intensity of gas in a pipe flow is about 5 percent. Using the Hinze-Tchen model (see 5.3.4.1), the ratio of the velocity fluctuation of the particles to that of the gas may be given by Eq. (5.196) as... 

Tchen, T.T. (1958). Mevalonic kinase purification and properties. J Biol Chem 233 1100-1103. 

Kumar A, Tchen P, Roullet F, Cohen J. Nonradioactive labeling of synthetic ohgonucletide probes with terminal deoxynucleotidyl transferase. Analyt. Biochem. 1988 169 376-382. 

Tchen,P., Fuchs, R.P.P., Sage, E, andLeng,M. (1984) Chemically modified nucleic acids as immunodetectable probes in hybridisation experiments Proc Natl Acad Set. USA 81, 3466-3470. 

Fiffure J02. Actions tchen you and your friend are held up,... 

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