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Several continuum methods for torsional analysis of slender perforated cores are described. First, the open section torsionbending theory, which neglects shear deformations, is described. It is then modified to consider shear deformations that become important with increasing lintel stiffness. To avoid the warping incompatibility, of the open section theory when applied to rigid lintel cores, a simple closed box torsionbending theory follows. Then an adaptation of the UmanskyBenscoter theory is presented. Finally, the alternating closed boxopen section model is described. These methods are compared with experimental data, finite element analysis, and the wide column frame analogy. It is concluded that the UmanskyBenscoter theory offers the most realistic modeling for relatively rigid lintel cores for which Bredt's formula becomes a simple alternative with increasing lintel stiffness. The open section theory, due to its simplicity, is adequate for more flexible systems.

A non-homogeneous membrane is a membrane that has variable thickness or material density. Several recent publications deal with the axisymmetric and antisymmetric modes of transverse vibration for a composite doubly connected and solid membrane with constant or variable density. In this paper, exact solutions for both the axisymmetric and antisymmetric modes of circular and annular membranes with any piecewise polynomial variation of the density are given using a power series solution. The dynamic problem is solved exactly using a recurrence relationship up to any accuracy desired, by deriving the dynamic stiffness matrix for circular and annular membrane elements. Many results for linear, parabolic, and cubic variation of complete and annular membranes are solved using the dynamic stiffness method and presented in the Tables.

This work presents a method to find the exact vibration frequencies of beams resting on variable one- and two-parameter elastic foundations. The proposed solution is based on a new method that enables one to find the dynamic stiffness matrix for the member including the effects of the variable foundation stiffness. The natural frequencies of vibrations are found as the frequency that causes the determinant of the stiffness matrix to be equal to zero. Several examples are given and compared to published results to demonstrate the accuracy and flexibility of the method. Copyright 1994, 1999 Academic Press

A stiffness approach is presented for computing the solution of beams on variable Winkler foundation. The solution may be achieved using only a small number of elements along the beam. Accuracy is dependent only on a preset user criterion. A numerical example demonstrates the efficiency and accuracy of the procedure.

Suramin is an investigational drug that has shown therapeutic activity in hormone-refractory metastatic prostate cancer in Phase I/II trials. Dose-limiting neurotoxicity remains the most serious complication of suramin treatment. We performed a prospective study to define the incidence, severity, characteristics, and dose relationships of suramin-induced peripheral neuropathy. Twenty-two patients who received suramin in a Phase-I trial underwent baseline and serial follow-up neurological evaluations consisting of history, examination, nerve conduction studies and quantitative sensory testing (QST). Suramin was administered intravenously in escalating dosages by using a 5-day schedule (repeated monthly), with the dose, determined by a population pharmacokinetic model, to accomplish 30-min post-infusion concentrations of 300 μg ml−1 (cohort I), 350 μg m−1 (cohort II) and 400 μg ml−1 (cohort III). Twelve patients developed a mild, axonal, length-dependent, sensory-motor polyneuropathy. Three other patients developed a subacutely progressive, functionally disabling, demyelinating neuropathy; sural nerve biopsy in two patients showed lymphocytic inflammation. These three patients improved after drug discontinuation and plasmapheresis. Although there was no apparent correlation between the cumulative dose and the severity of the neuropathy, no patient from cohort I, but 88% of patients from cohorts II and III, developed neuropathy. We conclude that when suramin is used at peak concentrations of ⋛350 μg ml−1 its administration is associated with two patterns of neuropathy, a distal axonal neuropathy and an inflammatory demyelinating neuropathy that is partially reversible. Neurological monitoring for development of neuropathy will improve the safety of suramin use in future clinical studies.