Drag discontinuity

Bakke, O.M., Wardell, W.M. and Lasagna, L. (1984). Drag discontinuations in the United Kingdom and United States, 1964-1983 Issues of safety. Clin. Pharmacol. Therapy 35 559-567. 

The solution of this simplest model just obtained brings the credible flow profiles for a duct with symmetric EPRs shown in Fig. 3.2. It can be seen that the velocity distribution varies from a parabolic shape (taking place in the absence of the EPR, A = 0 or <5 = 0) to a very distorted one which depends on the dimensionless density of the penetrable obstruction layer A. The shear stress keeps linear outside the obstruction layer but significantly bends within it. Both kinds of profiles quantitatively correspond to the experimental distributions measured in, for example, laboratory water flumes [231], Phenomenon of drag discontinuity (Chapter 6) can be observed at the top of the EPR that means that the profile r(z) is continuous but not differentiable. 

Figure 6.1 Three regimes of canopy flow. Three scales of turbulence are present. The smallest scale (black circles) is set by the canopy morphology, specifically the diameter of and spacing between individual canopy elements, such as stems and branches. Drag discontinuity at the canopy interface generates a shear-layer that produces vortices via Kelvin-Helmholtz (K-H) instability (shown as solid, black ovals). Boundary layer vortices are present above the canopy (dashed gray). When H/h is small the water surface constrains the boundary layer eddy scale.

Abdominal pain, esophagitis, nausea, vomiting, diarrhea, skin rash, and blood dyscrasias may be seen with the use of the lincosamides. These drag s also can cause pseudomembranous colitis, which may range from mild to very severe Discontinuing the drag may relieve mild symptoms of pseudomembranous colitis. 

Like the other anti-infectives, bacterial or fungal superinfections and pseudomembranous colitis (see Chap. 7) may occur with the use of these drags. The administration of the aminoglycosides may result in a hypersensitivity reaction, which can range from mild to severe and in some cases can be life threatening. Mild hypersensitivity reactions may only require discontinuing the drug, whereas the more serious reactions require immediate treatment. 

RISK FOR INEFFECTIVE TISSUE PERFUSION RENAL When the patient is taking a drag tiiat is potentially toxic to die kidneys, die nurse must carefully monitor fluid intake and output. In some instances, die nurse may need to perform hourly measurements of die urinary output. Periodic laboratory tests are usually ordered to monitor the patient s response to therapy and to detect toxic drag reactions. Seram creatinine levels and BUN levels are checked frequentiy during the course of therapy to monitor kidney function. If the BUN exceeds 40 mg dL or if the serum creatinine level exceeds 3 mg cIL, the primary health care provider may discontinue the drug therapy or reduce the dosage until renal function improves. 

Frequently seen adverse reactions to dragp with anticholinergic activity include dry mouth, blurred vision, dizziness, mild nausea, and nervousness. These may become less pronounced as therapy progresses. Other adverse reactions may include skin rash, urticaria (hives), urinary retention, dysuria, tachycardia, muscle weakness, disorientation, and confusion. If any of these reactions are severe, the drug may be discontinued for several days and restarted at a lower dosage, or a different antiparkinsonism drag may be prescribed. 

Drag interactions Live virus and live bacteria vaccines should not be administered to a patient receiving an immunosuppressive chemotherapeutic agent. At least three months should elapse between the discontinuation of chemotherapy and vaccination with a live vaccine. 

Observations of further solute-atom drag effects have been reviewed [2, 13], A number of effects measured as a function of driving pressure, temperature, and solute concentration appear to follow the general trends indicated in Fig. 13.6. The approximate nature of the model makes some discrepancies unsurprising. In Fig. 13.9, the discontinuous increases in boundary mobility as the temperature is increased are presumably caused by successive detachments of portions of a solute-atom atmosphere that exerted a drag on the boundaries. 

The implant consists of a tablet-shaped ganciclovir reservoir. The drag is initially completely coated with poly(vinyl alcohol) (PVA) and then coated with a discontinuous film of hydrophobic, dense poly (ethylene-co-vinyl acetate) (EVA). Both polymers are nonerodible and hydrophobic (the PVA used in the implant is cross-linked and/or high molecular weight, to ensure it does not dissolve when exposed to water). The entire assembly is coated again with PVA to which a suture tab made of PVA is attached (Figure 4.5). 

Huee antimalarial drags have polycyclic ring systems (Fig. 9-10) in common. The flrst is the common tetracycline anti biotic, doxycycline. The second is one of the newer drags luticated for malaria, halofantrine. The third is the discontinued agent used in the South Pacific, aminoacridine. 

Figure 6.9 Velocity profile in and above a submerged canopy. In the upper portion of the canopy flow is predominantly driven by turbulent stress, which penetrates downward into the canopy over attenuation scale (aCD) l. Below this flow is driven by potential gradients due to bed- or pressure gradients. At the top of the canopy the discontinuity in drag generates a mixing-layer. Above this the profile transitions to a logarithmic boundary layer profile.

As discussed earlier, the velocity profile near the top of the canopy is characterized by a region of strong shear arising from the discontinuity in drag. In this region the... 

Figure 6.11 The discontinuity in drag at the top of the canopy (z = h) creates a shear layer of width tml. The velocity difference across the layer is AU = U2 - U1. The layer penetrates downward into the canopy a distance Se from the canopy top.

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