Drag acting

If the relative velocity is sufficiently low, the fluid streamlines can follow the contour of the body almost completely all the way around (this is called creeping flow). For this case, the microscopic momentum balance equations in spherical coordinates for the two-dimensional flow [vr(r, 0), v0(r, 0)] of a Newtonian fluid were solved by Stokes for the distribution of pressure and the local stress components. These equations can then be integrated over the surface of the sphere to determine the total drag acting on the sphere, two-thirds of which results from viscous drag and one-third from the non-uniform pressure distribution (refered to as form drag). The result can be expressed in dimensionless form as a theoretical expression for the drag coefficient ... 

On the other hand, inter-individual differences in a drug s effects may also be observed in the presence of appropriate concentrations of the intended compound at the intended site of action, i.e., be due to differential pharmacodynamics. Here, two conceptually quite different conceptual scenarios may be distinguished that relate to the two principal mechanisms by which drags act etiology-specific and palliative. 

Stolerman IP, Fink R, Jarvik ME (1973) Acute and chronic tolerance to nicotine measured by activity in rats. Psychopharmacologia 30 329-342 Stolerman IP, Pratt JA, Garcha HS, Giardini V, Kumar R (1983) Nicotine cue in rats analysed with drags acting on cholinergic and 5-hydroxytryptamine mechanisms. Neuropharmacology 22 1029-1037... 

Research in the area of antiviral drag synthesis has only recently allowed a significant step to be made in the area of treating diseases caused by herpes simplex virus, and just recently for treating AIDS. These drags act by inhibiting the process of virus cell multiplication. 

The idea that drags act upon receptors began with Langley in 1878 [13], who introduced the term receptive substance [14]. However, the word receptor was introduced later, by Paul Ehrlich [15, 16]. During the first half of the 20th century, several observations highlighted the critical features associated with the... 

This complex barrier has to be crossed by drag molecules via passive diffusion or active transport in order to reach the brain compartment This is required for all drags acting on the central nervous system (CNS). The degree of uptake into the CNS or CSF can be quite different despite the similar mechanism involved in diffusion. This can be explained by the much greater surface of the blood-brain membrane compared to the surface of CSF and/or the existence of specific carrier proteins in the CNS. 

The example of Voltarol Retard, cited in the preceding section, is one of a company which has developed an innovative drag, acting to protect its franchise in that product when patent expiry draws near. Every proprietary product eventually loses its patent exclusivity (usually 20 years after the patent was applied for or granted) and it is then open to any other manufacturer to manufacture and sell the same drag, perhaps under its own brand name. It is, of course, necessary to obtain a license to manufacture and market the... 

FOMN — Ap co-down, particles fall by gravity with drag acting upward ... 

C What is the effect of streamlining on (o) friction drag and (b) pressure drag Does the total drag acting on a body necessarily decrease as a result of sireamlining Explain. 

Since the total frictional drag acting on the molecule must be divided among Ns + beads, the drag coefficient that one must assign to each bead should be inversely proportional to the number of beads Ns used to describe the chain. Hence, l b = N q/ Ns -1-1), where N is the number of monomers in the whole chain, and is the drag coefficient per monomer. Thus, Eq. (3-41) can be rearranged to a form that shows no dependence on Ng (Ferry 1980 Larson 1988) ... 

The experiment was short-lived, however. In the wake of controversy over the "doping" of Americans that prompted the Food and Drag Act of 1906, the federally sponsored project was terminated and the "dope" fields were eradicated, to be occupied years later by the Pentagon. 

On the premise that Americans were addicting themselves simply because they were unaware of the contents of the nostrums they were taking, the Pure Food and Drag Act of 1906 required that all patent medicines shipped across state lines had to list their ingredients if they contained more than a specified amount of opium, morphine, heroin, cocaine, alcohol, chloral hydrate, or cannabis. Three years later, Congress would adopt a second major drag law. This time, however, the impetus for such a law would come from international considerations. 

Later legislation for drag products focused on providing financial incentives to the pharmaceutical industry. The Orphan Drag Act of 1983 (13) stimulated investment in the development of drags to treat rare diseases or conditions affecting fewer that 200,000 persons in the United States. Manufacturers of orphan drag products enjoy seven years of market exclusivity if the products are not patentable... 

Market exclusivity is awarded for certain uses for a drug product, such as to treat or prevent orphan diseases. In this case, the most powerful incentive for a company to develop a product with a small target population is the Orphan Drag Act s market exclusivity clause. 

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