CD++: a toolkit to develop DEVS models

The features of a toolkit for modeling and simulation based on the DEVS formalism are presented. The tool is built as a set of independent software pieces running on different platforms. Not only are the main characteristics of the environment presented, a focus on its use is also considered by inclusion of application examples for a variety of problems. Many models can be defined in an automated fashion, simplifying the construction of new models and easing their verification. The use of this formal approach has allowed the development of safe and cost‐effective simulations, significantly reducing development time. Copyright © 2002 John Wiley & Sons, Ltd.     

Improved column-switching liquid chromatographic method for the determination of the enantiomers of mefloquine

A liquid chromatographic method for the determination of the enantiomers of mefloquine has been improved. The chromatography involved two columns: an achiral cyanopropyl stationary phase for the quantification of (+/-)-mefloquine and a chiral naphthyl-urea stationary phase for the determination of the enantiomeric ratio. Compared with the previous method, which needed two detectors, this one used one detector-integrator to which the two columns are connected alternately by an automated column-switching system. The method is suitable for the quantification (0.05 microgram/ml) of mefloquine and the determination of enantiomeric ratios from 500-microliters plasma samples with ultraviolet detection.     

Cisapride reduces neonatal postoperative ileus: randomised placebo controlled trial

AIM: To assess the efficacy of cisapride in reducing ileus persisting to the tenth postoperative day after neonatal abdominal surgery. METHODS: A prospective, randomised, double blind trial comparing rectal cisapride (1.4-2.3 mg/kg/day) with placebo over seven days was undertaken in 33 neonates. RESULTS: Seven of 12 (58%) patients receiving placebo and eight of 11 (73%) receiving cisapride achieved a first sustained feed during treatment. Of those receiving cisapride, the first sustained feed occurred at 2.3 days (SEM 0.6) compared with 4.7 days (SEM 0.8) with placebo. By the seventh day the mean daily net enteral balance was 69 (SEM 18) ml/kg in the cisapride subgroup and 17 (SEM 8) ml/kg for those receiving placebo. Stool was passed on 6.3 (SEM 0.4) treatment days in the cisapride subgroup compared with 4.1 (SEM 1.0) treatment days in the placebo subgroup. CONCLUSION: Cisapride is effective in neonates with a prolonged ileus after abdominal surgery.     

The synthesis and in vitro characterization of the mucoadhesion and swelling of poly(acrylic acid) hydrogels

Depression is a significant problem in epilepsy. Suicides occur in epileptic patients five times more often than in general population. Material included 34 epileptics with 76 suicidal attempts and 24 patients with no history of suicide. Psychical state was studied with Beck Depression Inventory and Hamilton Depression Rating Scale. In the group with suicidal attempts 65% of patients had depression (54.5% of them had major depression) and in group without suicide attempts depression was noted in 54% (23% with major depression). Patients with depression were divided into two groups: group I with suicidal attempts and group II without history of suicide. In group I more patients were alcohol abusers (50% vs 31%), more were treated because of epilepsy longer than 10 years (59% vs 46%) and more had tonic-clonic seizures (82% vs 46%). In group I, 54% of patients were on polytherapy (more than half of them with fenobarbital). In group II, 31% of epileptics were on polytherapy (no one with fenobarbital). Major depression was significantly more frequent in epileptics with suicidal attempts. The severity of depression may influence the risk of suicide. Major depression may be associated with late age of onset of epilepsy, longer treatment duration, tonic-clonic seizures, polytherapy (mainly with fenobarbital) and alcohol abuse.     

Glutathione and catalase provide overlapping defenses for protection against hydrogen peroxide in the yeast Saccharomyces cerevisiae

Glutathione (GSH) is an abundant and ubiquitous low-molecular-weight thiol which has proposed roles in many cellular processes including protection against the deleterious effects of reactive oxygen species. Our experiments have addressed the role of GSH in protection against hydrogen peroxide in the yeast Saccharomyces cerevisiae, and have shown that GSH and catalase provide overlapping defense systems. GSH appears to be the primary antioxidant for protection against hydrogen peroxide since mutants lacking GSH (gsh1) or glutathione reductase (glr1) are sensitive, whereas, strains lacking catalase A (cta1) or catalase T (ctt1) are unaffected in resistance to this oxidant. Furthermore, following treatment with hydrogen peroxide, the levels of oxidized, protein-bound and extracellular GSH were all increased at the expense of intracellular GSH. However, there are two lines of evidence that indicate catalases are required in the absence of GSH; firstly, strains that lack both catalase A and T accumulate increased levels of oxidized glutathione following treatment with hydrogen peroxide; and secondly, deletion of catalase genes exacerbates the hydrogen peroxide sensitivity of glr1 and gsh1 mutants.     

DW-RBAC: A formal security model of delegation and revocation in workflow systems

One reason workflow systems have been criticized as being inflexible is that they lack support for delegation. This paper shows how delegation can be introduced in a workflow system by extending the role-based access control (RBAC) model. The current RBAC model is a security mechanism to implement access control in organizations by allowing users to be assigned to roles and privileges to be associated with the roles. Thus, users can perform tasks based on the privileges possessed by their own role or roles they inherit by virtue of their organizational position. However, there is no easy way to handle delegations within this model. This paper tries to treat the issues surrounding delegation in workflow systems in a comprehensive way. We show how delegations can be incorporated into the RBAC model in a simple and straightforward manner. The new extended model is called RBAC with delegation in a workflow context (DW-RBAC). It allows for delegations to be specified from a user to another user, and later revoked when the delegation is no longer required. The implications of such specifications and their subsequent revocations are examined. Several formal definitions for assertion, acceptance, execution and revocation are provided, and proofs are given for the important properties of our delegation framework.     

Algorithms for anomaly detection of traces in logs of process aware information systems

This paper discusses four algorithms for detecting anomalies in logs of process aware systems. One of the algorithms only marks as potential anomalies traces that are infrequent in the log. The other three algorithms: threshold, iterative and sampling are based on mining a process model from the log, or a subset of it. The algorithms were evaluated on a set of 1500 artificial logs, with different profiles on the number of anomalous traces and the number of times each anomalous traces was present in the log. The sampling algorithm proved to be the most effective solution. We also applied the algorithm to a real log, and compared the resulting detected anomalous traces with the ones detected by a different procedure that relies on manual choices.     

ST-Audit: guideline-based automatic auditing of electronic patient records

This work presents the ST-Audit system that audits a patient record for conformance to a particular clinical guideline. The system uses ST-Guide which models a guideline as a set of states and transitions. The audit system tries to find a path in the state/transition diagram that corresponds to the actions taken by the physician, taking into consideration issues such as the unavailability of all the data needed to evaluate the transitions. The system was used to audit an outpatient clinic regarding their procedure for hypertension treatment (using the VI JNC guideline for hypertension), and the results of the number of non-compliant actions were presented and discussed. A follow up auditing showed a small but statistically significant reduction on the number of non-compliant actions for patients treated after the first audit.     

Saving Sergeant Buske. An account of remarkable valor and amazing survival from the records of the 65th General Hospital, a Duke University Army Reserve Unit of World War II

BACKGROUND: Attentional processes are assumed to play an important role in the maintenance of illness anxiety, although empirical support is relatively scarce. METHODS: The present study explores the relationship between selective attention (i.e. private body consciousness and symptom reporting), intensive concentration (i.e. attentional control and sustained attention), and illness anxiety in 57 non-clinical subjects. RESULTS: Zero-order and multiple correlations suggest that illness anxiety is significantly related to cognitive failures in everyday life and private body consciousness and to a lesser extent to symptom reporting. CONCLUSION: It is concluded that illness anxiety can be partly predicted from specific attentional variables. However, specific operationalizations of attentional parameters seems to determine the existence and magnitude of these relations.