Nonlinear diffusion and thermo-electric coupling in a two-variable model of cardiac action potential.

This work reports the results of the theoretical investigation of nonlinear dynamics and spiral wave breakup in a generalized two-variable model of cardiac action potential accounting for thermo-electric coupling and diffusion nonlinearities. As customary in excitable media, the common Q10 and Moore factors are used to describe thermo-electric feedback in a 10° range. Motivated by the porous nature of the cardiac tissue, in this study we also propose a nonlinear Fickian flux formulated by Taylor expanding the voltage dependent diffusion coefficient up to quadratic terms. A fine tuning of the diffusive parameters is performed a priori to match the conduction velocity of the equivalent cable model. The resulting combined effects are then studied by numerically simulating different stimulation protocols on a one-dimensional cable. Model features are compared in terms of action potential morphology, restitution curves, frequency spectra, and spatio-temporal phase differences. Two-dimensional long-run simulations are finally performed to characterize spiral breakup during sustained fibrillation at different thermal states. Temperature and nonlinear diffusion effects are found to impact the repolarization phase of the action potential wave with non-monotone patterns and to increase the propensity of arrhythmogenesis.

Active client participation: an examination of self-empowerment in HIV/AIDS case management with women.

Case management has become increasingly popular as a means to alleviate the difficulties associated with accessing health care and social services. However, little information exists regarding models of case management specifically intended for work with HIV-positive women. This article explores the practices currently in use at an HIV/AIDS service agency to further define empowering practices employed by case managers working with HIV-positive women. Although a client's active participation in service plan development and delivery is widely regarded as the pathway to empowerment, findings indicate that "active participation" is not so readily defined; empowerment exists on a dynamic continuum with increasing levels of client participation. A model is presented that demonstrates the relationship of particular behaviors to client self-empowerment. Because the needs of clients with HIV/AIDS are continually fluctuating, and because case managers' behaviors will need to adapt accordingly, this model also incorporates the concept of balance as it pertains to HIV/AIDS case management.

Caregivers of HIV/AIDS patients need care themselves.

AIDS: Family and friends of HIV/AIDS patients are informal caregivers that can provide significant social support and practical assistance for patients. However, social workers and other professionals often fail to take a caregiver's needs into account. Caregivers and AIDS patients can suffer from similar types of grief, stress, and stigmatisms. Caregivers often overcompensate for their stress by taking on duties beyond their physical and emotional limits.^ieng

Effect of taurine supplementation on fat and energy absorption in cystic fibrosis.

In 10 children with cystic fibrosis and persisting steatorrhoea, supplementation with taurine (30-40 mg/kg/day) was given for two months as an adjunct to the usual pancreatic enzyme treatment. A three day fat and energy balance was performed in patients with cystic fibrosis, before and after the supplementation, and in seven healthy controls who did not receive taurine. Faecal fat was measured by a gravimetric method and stool energy was determined using a bomb calorimeter. Patients with cystic fibrosis, before and after taurine, and healthy controls received the same fat and energy intake (calculated by a dietitian). In patients with cystic fibrosis taurine did not produce any improvement of steatorrhoea (mean (SD) faecal fat 8.7 (3.3) v 11.2 (7.0) g/day, respectively before and after the supplementation), of faecal energy loss (0.978 (0.468) v 1.133 (0.539) MJ/day), of faecal fat expressed as percent of fat intake (13.4 (5.6) v 15.1 (9.8)%), and of faecal energy expressed as percent of energy intake (9.9 (3.6) v 11.2 (5.7)%). Healthy controls had significant lower fat (3.5 (2.3) g/day) and energy 0.576 (0.355) MJ/day faecal losses. In conclusion, taurine failed to decrease significantly fat and energy losses. Our study does not support the use of taurine supplementation in the nutritional management of cystic fibrosis.