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Computing the steady state of multistage counter‐current processes like distillation, extraction, or absorption is the equivalent to finding solutions for large‐scale nonlinear equation systems. The conventional solution techniques are fast and efficient if a good estimation is available, but are prone to fail, and do not provide information about the reason for the failure. This is the main motive to apply reliable methods in solving them. Reliable computations are usually realized with interval methods. A reliable root finding method is presented, based on affine arithmetic (AA), a recently developed linearization technique and interval method. AA is compared here to another linearization technique, the widely known Interval Newton method. The studied examples seem to indicate superiority of the novel method over the traditional one. The comparison is made with a pruning technique not state‐of‐the‐art, but analogous in the two compared methods. AA can be combined with constraint propagation (CP), or linear programming (LP) aided CP, as pruning techniques. The combined techniques, AA/CP and AA/LP are studied and compared. AA/LP proves to be preferable because of its robustness. Short distillation columns are successfully computed with the proposed AA/LP method. © 2008 American Institute of Chemical Engineers AIChE J, 2008

CSP #221 is a randomized multiinstitutional clinical trial to assess the efficacy of 10 d of perioperative total parenteral nutrition (TPN) in reducing morbidity and mortality in malnourished patients undergoing intraperitoneal and/or intrathoracic operations. In this paper a detailed protocol for the clinical efficacy trial is presented primarily as a reference document for use in interpretation of the results of the clinical trial. It is also anticipated, however, that review of this protocol may be useful to other investigators planning future clinical nutrition intervention trials.

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Most clinicians subjectively feel that malnutrition in surgical patients is associated with poor clinical outcome. This overview provides a chronologic review of studies relating poor nutritional status to increased surgical morbidity. Techniques for identifying surgical patients with clinically important nutritional deficits are discussed. Retrospective and/or non-randomized clinical studies evaluating the efficacy of perioperative forced feeding are reviewed. These data suggest a possible role for preoperative nutritional support of selected malnourished surgical candidates and provide the rationale for a large-scale nutrition-intervention clinical trial.