An H-minimax approach to the design of robust control systems

A realistic feedback design problem is posed based on the minimization of a weighted combination of the sensitivity and complementary sensitivity matrices. A solution is obtained which makes use of the recently proposed methods for minimizing the sensitivity function alone.     

Primary carcinoma of duodenum--a case report

The toad gallbladder epithelium is much more selective than that of the rabbit especially as to the permeability of two molecules like urea and thiourea. These observations can probably be attributed to different permeation mechanisms of the 2 molecules. Neither active transport nor solvent drag can explain these phenomena. 10(-4) M phloretin strongly inhibits urea movement, but does not alter either thiourea fluxes or isotonic net water transport: these results suggest that a specific mechanism is involved in urea movement. The urea transport shows saturation kinetic which is consistent with the presence of a facilitated mechanism.     

Relative strength of scleral tunnel incisions with internal corneal lips constructed in cadaver eyes

We constructed scleral tunnel wounds with internal corneal lips and sutureless closures in ten cadaver eyes without previous intraocular surgery. Each wound differed in width, total incision length, and internal corneal lip size. At a low and high range of initial intraocular pressure (IOP, 10 to 15 mm Hg or 20 to 25 mm Hg), we compared the wounds' resistance to leakage during application of external pressure. A square wound with a 4.0 mm width and 4.0 mm overall length, including a 1.5 mm corneal lip, had the optimum wound dimensions. These produced a stable incision that resisted leakage at external pressures up to 525 pounds per square inch equally well at both IOP ranges. Leakage occurred at lower external pressures for wounds with greater width, smaller corneal lips, or wound widths that were greater than wound lengths; such wounds were also more prone to leakage at the low IOP range. When constructed properly and adequately, the 4.0 mm wide scleral tunnel incision with 1.5 mm internal corneal lip is a strong and safe wound for sutureless cataract surgery.