Granular shear flow dynamics and forces: experiment and continuum theory.

We analyze the main features of granular shear flow through experimental measurements in a Couette geometry and a comparison to a locally Newtonian, continuum model of granular flow. The model is based on earlier hydrodynamic models, adjusted to take into account the experimentally observed coupling between fluctuations in particle motion and mean-flow properties. Experimentally, the local velocity fluctuations are found to decrease more slowly with distance from the shear surface than the velocity. This can be explained by an effective viscosity that diverges more rapidly as the random-close-packing density is approached than is predicted by Enskog theory for dense hard-sphere systems. Experiment and theory are in good agreement, especially for the following key features of granular flow: The flow is confined to a small shear band, fluctuations decay approximately exponentially away from the sheared wall, and the shear stress is approximately independent of the shear velocity. The functional forms of the velocity and fluctuation profiles predicted by the model agree with the experimental results.

Computerized relational database for monitoring clozapine therapy.

The use of a computerized relational database to satisfy the patient-monitoring requirements of clozapine's manufacturer at an Oregon state psychiatric facility is described. The pharmacy department designed a computerized system to efficiently manage the patient-monitoring requirements of clozapine's manufacturer. A relational database program allows information in database files to be readily retrieved and organized into standardized or customized reports. These reports provide white blood cell (WBC) counts to the drug's manufacturer, patient discharge information to other clozapine providers, psychiatric test results to treating physicians, financial data to hospital administration, and other key data related to the facility's clozapine treatment system. The computerized system minimized the additional workload required to dispense clozapine, decreased the cost of clozapine by $234,441 compared with the cost under the closed distribution system, and provided for comprehensive clinical monitoring. Between May 1991 and October 1992, 168 clozapine recipients were monitored; pharmacists notified physicians about 86 patients not meeting WBC-count criteria. The use of a computerized relational database enabled a state psychiatric hospital to efficiently manage the burden of monitoring clozapine recipients.

Impact of clozapine on medication use in a state hospital.

Medical records of 90 consecutive patients who started clozapine were reviewed to see how this drug is being used with other psychotropic medications and to evaluate what impact it has had on the drug regimens of these patients. Data from up to 6 months before to 12 months after clozapine's initiation was included. The percent of patients receiving medications for antipsychotic side effects decreased from 86% 6 months prior to clozapine to 13% 12 months after. The use of benzodiazepines decreased from 43% to 23% during this time period as did lithium use from 57% to 17%. While 28% of the patients were receiving carbamazepine prior to starting clozapine, no patients remained on this drug concurrently with clozapine. The average number of psychiatric medications per patient decreased from 3.39 +/- 1.37 6 months prior to clozapine to 1.61 +/- .83 at month 12. Concern for drug interactions along with clozapine's reduced incidence of extrapyramidal side effects and increased efficacy contributed to the reduction in medication use observed.