Beyond neuropathy in hereditary sensory and autonomic neuropathy type V: cognitive evaluation

Background and purpose: Hereditary sensory and autonomic neuropathy ( HSAN) type V is a very rare disorder. It is characterized by the absence of thermal and mechanical pain perception caused by decreased number of small diameter neurons in peripheral nerves. Recent genetic studies have pointed out the aetiological role of nerve growth factor beta, which is also involved in the development of the autonomic nervous system and cholinergic pathways in the brain. HSAN type V is usually reported not to cause mental retardation or cognitive decline. However, a structured assessment of the cognitive pro. le of these patients has never been made. Methods and results: We performed a throughout evaluation of four HSAN type V patients and compared their performance with 37 normal individuals. Our patients showed no cognitive deficits, not even mild ones. Discussion and Conclusions: Although newer mutations on this and related disorders are continuously described, their clinical characterization has been restricted to the peripheral aspects of these conditions. A broader characterization of this rare disorder may contribute to better understand the mechanisms of the nociceptive and cognitive aspects of pain.

Thermal/mechanical simulation and laboratory fatigue testing of an alternative yttria tetragonal zirconia polycrystal core-veneer all-ceramic layered crown design

This study evaluated the stress levels at the core layer and the veneer layer of zirconia crowns (comprising an alternative core design vs. a standard core design) under mechanical/thermal simulation, and subjected simulated models to laboratory mouth-motion fatigue. The dimensions of a mandibular first molar were imported into computer-aided design (CAD) software and a tooth preparation was modeled. A crown was designed using the space between the original tooth and the prepared tooth. The alternative core presented an additional lingual shoulder that lowered the veneer bulk of the cusps. Finite element analyses evaluated the residual maximum principal stresses fields at the core and veneer of both designs under loading and when cooled from 900 degrees C to 25 degrees C. Crowns were fabricated and mouth-motion fatigued, generating master Weibull curves and reliability data. Thermal modeling showed low residual stress fields throughout the bulk of the cusps for both groups. Mechanical simulation depicted a shift in stress levels to the core of the alternative design compared with the standard design. Significantly higher reliability was found for the alternative core. Regardless of the alternative configuration, thermal and mechanical computer simulations showed stress in the alternative core design comparable and higher to that of the standard configuration, respectively. Such a mechanical scenario probably led to the higher reliability of the alternative design under fatigue.

Cognitive behaviour therapy for the management of obsessive-compulsive disorder

Current research reflects conflict regarding best practice in the treatment of obsessive-compulsive disorder (OCD). The. present study reports on the psychological treatment of a 54-year-old woman diagnosed with OCD, and follows the implementation of pharmacological treatment. The study utilises both exposure and response prevention (ERP) and cognitive therapy (CT), although there was no attempt to compare these approaches in an experimental design. Measures of avoiding and neutralising behaviours were taken on three occasions across treatment. Measures were also taken of intrusive thoughts, appraisal of responsibility, and effective challenging, both across treatment and at follow-up. The results indicate that gains were made in addition to those reported following the implementation of medication. The results also suggest that the addition of CT to exposure and response prevention facilitates the extinction of neutralising behaviours.

Step size control for efficient discrete element simulation

The step size determines the accuracy of a discrete element simulation. The position and velocity updating calculation uses a pre-calculated table and hence the control of step size can not use the integration formulas for step size control. A step size control scheme for use with the table driven velocity and position calculation uses the difference between the calculation result from one big step and that from two small steps. This variable time step size method chooses the suitable time step size for each particle at each step automatically according to the conditions. Simulation using fixed time step method is compared with that of using variable time step method. The difference in computation time for the same accuracy using a variable step size (compared to the fixed step) depends on the particular problem. For a simple test case the times are roughly similar. However, the variable step size gives the required accuracy on the first run. A fixed step size may require several runs to check the simulation accuracy or a conservative step size that results in longer run times. (C) 2001 Elsevier Science Ltd. All rights reserved.

A systematic approach to error isolation in computerized wastewater simulation models

Activated sludge models are used extensively in the study of wastewater treatment processes. While various commercial implementations of these models are available, there are many people who need to code models themselves using the simulation packages available to them, Quality assurance of such models is difficult. While benchmarking problems have been developed and are available, the comparison of simulation data with that of commercial models leads only to the detection, not the isolation of errors. To identify the errors in the code is time-consuming. In this paper, we address the problem by developing a systematic and largely automated approach to the isolation of coding errors. There are three steps: firstly, possible errors are classified according to their place in the model structure and a feature matrix is established for each class of errors. Secondly, an observer is designed to generate residuals, such that each class of errors imposes a subspace, spanned by its feature matrix, on the residuals. Finally. localising the residuals in a subspace isolates coding errors. The algorithm proved capable of rapidly and reliably isolating a variety of single and simultaneous errors in a case study using the ASM 1 activated sludge model. In this paper a newly coded model was verified against a known implementation. The method is also applicable to simultaneous verification of any two independent implementations, hence is useful in commercial model development.

Time-dependent master equation simulation of complex elementary reactions in combustion: Application to the reaction of (CH2)-C-1 with C2H2 from 300-2000 K

Computational simulations of the title reaction are presented, covering a temperature range from 300 to 2000 K. At lower temperatures we find that initial formation of the cyclopropene complex by addition of methylene to acetylene is irreversible, as is the stabilisation process via collisional energy transfer. Product branching between propargyl and the stable isomers is predicted at 300 K as a function of pressure for the first time. At intermediate temperatures (1200 K), complex temporal evolution involving multiple steady states begins to emerge. At high temperatures (2000 K) the timescale for subsequent unimolecular decay of thermalized intermediates begins to impinge on the timescale for reaction of methylene, such that the rate of formation of propargyl product does not admit a simple analysis in terms of a single time-independent rate constant until the methylene supply becomes depleted. Likewise, at the elevated temperatures the thermalized intermediates cannot be regarded as irreversible product channels. Our solution algorithm involves spectral propagation of a symmetrised version of the discretized master equation matrix, and is implemented in a high precision environment which makes hitherto unachievable low-temperature modelling a reality.

Using clusters of computers for large QU-GENE simulation experiments

The QU-GENE Computing Cluster (QCC) is a hardware and software solution to the automation and speedup of large QU-GENE (QUantitative GENEtics) simulation experiments that are designed to examine the properties of genetic models, particularly those that involve factorial combinations of treatment levels. QCC automates the management of the distribution of components of the simulation experiments among the networked single-processor computers to achieve the speedup.

The future of cognitive and behavioral therapies in the prevention and early management of psychosis: Opportunities and risks

Behavioral and cognitive interventions for people with psychosis have a long and distinguished history, although the evidence for their application to young people remains limited. We anticipate that the next decades will show substantial research into psychological intervention for this population. Important targets will include the management of environmental stressors, reduction of substance misuse, and promotion of early treatment. Psychological management of positive symptoms, depression, and suicidal behavior will continue to be critical objectives. Important secondary prevention goals will be the retention of cognitive functioning, vocational options, social skills, and social network support, including appropriate family support. We expect primary prevention to include both universal programs and interventions for adolescents at particularly high risk. Technical innovations will include increasing use of Internet-based intervention and behavior cueing devices. Pressures for intervention brevity will continue, as will problems with the systematic delivery of effective procedures.

A simulation model for analysing patient activity in dermatology

We developed a general model to assess patient activity within the primary and secondary health-care sectors following a dermatology outpatient consultation. Based on observed variables from the UK teledermatology trial, the model showed that up to 11 doctor-patient interactions occurred before a patient was ultimately discharged from care. In a cohort of 1000 patients, the average number of health-care visits was 2.4 (range 1-11). Simulation analysis suggested that the most important parameter affecting the total number of doctor-patient Interactions is patient discharge from care following the initial consultation. This implies that resources should be concentrated in this area. The introduction of teledermatology (either realtime or store and forward) changes the values of the model parameters. The model provides a quantitative tool for planning the future provision of dermatology health-care.

Outpatient cognitive behavioural therapy programme for alcohol dependence impact of naltrexone use on outcome

Objective: Cognitive-behavioural therapy (CBT) has been effectively used in the treatment of alcohol dependence. Clinical studies report that the anticraving drug naltrexone, is a useful adjunct to treatment. Currently, few data are available on the impact of adding this medication to programmes in more typical, outpatient, and rehabilitation settings. The objective of this study was to examine the impact on outcome of adding naltrexone to an established outpatient alcohol rehabilitation program which employed CBT. Method: Fifty patients participated in an established 12-week, outpatient, 'contract'-based alcohol abstinence programme which employed CBT. They also received naltrexone 50 mg orally daily (CBT + naltrexone). Outcomes were compared with 50 historical, matched controls, all of whom participated in the same programme without an anticraving medication (CBT alone). All patients met DSM-IV criteria for alcohol dependence. Results: Programme attendance across the eight treatment sessions was lower in the CBT alone group (p < 0.001). Relapse to alcohol use occurred sooner and more frequently in the CBT alone group (p < 0.001). Rehabilitation programme completion at 12 weeks was 88% (CBT + naltrexone) compared with 36% for (CBT alone) (p < 0.001). Alcohol abstinence at 12 weeks was 76% (CBT + naltrexone) compared with 18% (CBT alone) (p < 0.001). Conclusion: When employing the same outpatient rehabilitation programme and comparing outcomes using matched historical controls, the addition of naltrexone substantially improves programme attendance, programme completion and reported alcohol abstinence. In a typical outpatient programme, naltrexone addition was associated with significantly improved programme participation, better outcomes and was well tolerated.