Computer-assisted intervention improves patient-centered diabetes care by increasing autonomy support.

Objective: To determine if a patient-centered, computer-assisted diabetes care intervention increased perceived autonomy support, perceived competence (from self-determination theory), and if these constructs mediated the effect of the intervention on ADA/NCQA recommended diabetes care outcomes. Design: A randomized controlled trial of 866 adult type 2 diabetes patients in heterogeneous primary care settings in Colorado. Main Outcome Measures: Perceived autonomy support, perceived competence, patient satisfaction, glycemic control (HbA1c), ratio of total to HDL cholesterol, diabetes distress, and depressive symptoms. Results: The computer-assisted intervention increased patient perception of autonomy support relative to a computer-based control condition ( p = .05). Change in perceived competence partially mediated the effects of increased autonomy support on the change in lipids, diabetes distress, and depressive symptoms. The construct of autonomy support was found to be separate from that of patient satisfaction. Conclusions: A patient-centered, computer-assisted intervention was effective in improving diabetes self-management outcomes, in part, because it increased patients' perception that their autonomy was supported which changed perceived competence. These findings support the self-determination model for health behavior change and the chronic care model and support the further study of the use of these technologies to motivate patients to improve their health outcomes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Experimental Validation of a Helicopter Autopilot Design using Model-Based PID Control

Autonomous helicopter flight provides a challenging control problem. In order to evaluate control designs, an experimental platform must be developed in order to conduct flight tests. However, the literature describing existing platforms focuses on the hardware details, while little information is given regarding software design and control algorithm implementation. This paper presents the design, implementation, and validation of an experimental helicopter platform with a primary focus on a software framework optimized for controller development. In order to validate the operation of this platform and provide a basis for comparison with more sophisticated nonlinear designs, a PID controller with feedforward gravity compensation is derived using the generally accepted small helicopter model and tested experimentally.     

Investigation of sheet resistance in thin-film mixed-conducting solid oxide fuel cell cathode test cells

Patterned and thin-film electrode experiments are effective in isolating or separating the complex charge and mass transport processes involved in the oxygen reduction reaction within and on the surface of a mixed-conducting solid oxide fuel cell cathode, making it possible to correlate electrochemical performance with electrode geometry, reaction pathway, and limiting steps. Very little information about either the impact of sheet resistance on global response or on effective design of current collector configuration to avoid sheet resistance has been reported to date, however. In this contribution, an empirical numerical model is presented to simulate sheet resistance under various material and catalytic parameters, current collector configurations, and other experimental factors in thin-film, mixed-conducting working electrodes. This model is used to provide general guidance for effective current collector placement by mapping in parameter space. In general, continuous crisscrossing metal lines, deposited through e.g. photolithography, provide the best intra-film current collection while small, regularly spaced discrete contacts, provided by e.g. a metal mesh, provide less efficient intra-film current collection. Most thin-film aspect ratios and current collector configurations can be accommodated without severe intra-film sheet resistance limitation provided the current collectors are spaced appropriately.     

Henrian activity coefficient of As in Cu-Fe mattes and white metal

A transpiration method was used to evaluate the Henrian activity coefficient of As (γ _As ^o ) in Cu-Fe mattes and white metal. Values for the activity coefficient of As (γ _As) have been evaluated as a function of the Cu/Fe molar ratio from 1 to ∞, as a function of the sulfur deficiency (defined as SD=X _s−1/2X _Cu−X _Fe, where X _i is the mole fraction of the ith species) from −0.02 to +0.02 and at temperatures between 1493 and 1573 K. The activity coefficient for arsenic in the matte was found to have a weak dependence on both temperature and the Cu/Fe molar ratio, but a strong dependence on SD. Analysis of γ _As as a function of the trace-element concentration reveals that the activity coefficient is highly dependent on the As content, even at trace concentrations where Henrian behavior is expected. That dependency is attributed to uncertainty in the reported value of the saturation pressure of monatomic arsenic (P _As ^o ) and highlights problems in comparing results and specifying Henrian values for the activity coefficient. A method is presented whereby the impact of P _As ^o on computed values of γ _As is significantly reduced to obtain an approximate Henrian value of the activity coefficient.     

Printed, flexible electrochromic displays using interdigitated electrodes

We describe herein some of our initial studies in pursuit of a simple, economical method of mass producing electrochromic displays. The approach we have taken is to print the display on polymer film utilizing commercially available conductive inks in an interdigitated electrode structure with a conductive metal oxide powder, dispersed in a polymer binder, as the electrode surface. A range of electrochromic materials suitable for use with an aqueous gel electrolyte have been explored and examples presented.     

Role of the endothelium in placental dysfunction after fetal cardiac bypass

BACKGROUND: Fetal cardiac bypass causes placental dysfunction, characterized by increased placental vascular resistance, decreased placental blood flow, hypoxia, and acidosis. Vasoactive factors produced by the vascular endothelium, such as nitric oxide and endothelin 1, are important regulators of placental vascular tone and may contribute to this placental dysfunction. METHODS: To investigate the role of the vascular endothelium in placental dysfunction related to fetal cardiac bypass, we studied 3 groups of fetal sheep. In the first group (n = 7) we determined placental hemodynamic responses before and after bypass to an endothelium-dependent vasodilator (acetylcholine), an endothelium-independent vasodilator (nitroprusside), and endothelin 1. In the second group (n = 8) a nonspecific endothelin receptor blocker (PD 145065) was administered and placental hemodynamic values were measured before and after bypass. In the third group (n = 5) endothelin 1 levels were measured before and after bypass. RESULTS: Before fetal cardiac bypass exogenous endothelin 1 decreased placental blood flow by 9% and increased placental resistance by 9%. After bypass endothelin 1 decreased placental flow by 47% and increased resistance by 106%. There was also a significant attenuation of the placental vascular relaxation response to acetylcholine after bypass, whereas the response to nitroprusside was not significantly altered. In fetuses that received the PD 145065, placental vascular resistance increased significantly less than in control fetuses (28% versus 62%). Similarly, placental blood flow decreased significantly more (from 6. 3 +/- 3.1 to 28.3 +/- 10.4 pg/mL; P =.01) in control fetuses than in fetuses receiving PD 145065 (33% versus 20%). Umbilical venous endothelin 1 levels increased significantly in fetuses exposed to fetal bypass but did not change in control fetuses. CONCLUSIONS: The basal endothelial regulatory mechanisms of placental vascular tone were deranged after fetal cardiac bypass. Endothelin receptor blockade, which substantially reduced postbypass placental dysfunction, and other interventions aimed at preserving endothelial function may be effective means of optimizing fetal outcome after cardiac bypass.     

Endothelin receptor blockade prevents the rise in pulmonary vascular resistance after cardiopulmonary bypass in lambs with increased pulmonary blood flow

BACKGROUND: Children with increased pulmonary blood flow may experience morbidity as the result of increased pulmonary vascular resistance after operations in which cardiopulmonary bypass is used. Plasma levels of endothelin-1, a potent vasoactive substance implicated in pulmonary hypertension, are increased after cardiopulmonary bypass. OBJECTIVES: In a lamb model of increased pulmonary blood flow after in utero placement of an aortopulmonary shunt, we characterized the changes in pulmonary vascular resistance induced by hypothermic cardiopulmonary bypass and investigated the role of endothelin-1 and endothelin-A receptor activation in postbypass pulmonary hypertension. METHODS: In eleven 1-month-old lambs, the shunt was closed, and vascular pressures and blood flows were monitored. An infusion of a selective endothelin-A receptor blocker (PD 156707; 1.0 mg/kg/h) or drug vehicle (saline solution) was then begun 30 minutes before cardiopulmonary bypass and continued for 4 hours after bypass. The hemodynamic variables were monitored, and plasma endothelin-1 concentrations were determined before, during, and for 6 hours after cardiopulmonary bypass. RESULTS: After 90 minutes of hypothermic cardiopulmonary bypass, both pulmonary arterial pressure and pulmonary vascular resistance increased significantly in saline-treated lambs during the 6-hour study period (P <.05). In lambs pretreated with PD 156707, pulmonary arterial pressure and pulmonary vascular resistance decreased (P <. 05). After bypass, plasma endothelin-1 concentrations increased in all lambs; there was a positive correlation between postbypass pulmonary vascular resistance and plasma endothelin-1 concentrations (P <.05). CONCLUSIONS: This study suggests that endothelin-A receptor-induced pulmonary vasoconstriction mediates, in part, the rise in pulmonary vascular resistance after cardiopulmonary bypass. Endothelin-A receptor antagonists may decrease morbidity in children at risk for postbypass pulmonary hypertension. This potential therapy warrants further investigation.     

The effect of dietary Laminaria‐derived laminarin and fucoidan on nutrient digestibility,nitrogen utilisation,intestinal microflora and volatile fatty acid concentration in pigs

BACKGROUND: In experiment 1, 30 boars were assigned to one of five treatments (n = 6): T1, 0 g kg^?1 seaweed extract (SWE); T2, 0.7 g kg^?1 SWE; T3, 1.4 g kg^?1 SWE; T4, 2.8 g kg^?1 SWE and T5, 5.6 g kg^?1 SWE. The extract contained laminarin and fucoidan only and was extracted from Laminaria spp. In experiment 2, 28 boars were assigned, in a 2 × 2 factorial to one of four treatments (n = 7): T1, control; T2, control plus 300 mg laminarin; T3, control plus 240 mg fucoidan; T4, control plus 300 mg laminarin and 240 mg fucoidan kg^?1 diet. RESULTS: In experiment 1 there was a response to SWE on colonic Bifidobacterium spp. (P < 0.01 quadratic), Enterobacterium spp. (quadratic P < 0.05) and on caecal Enterobacterium spp. (quadratic P < 0.05). In experiment 2 there was an interaction (P < 0.05) between laminarin and fucoidan supplementation on Enterobacterium spp. in the proximal and distal colon. Pigs offered laminarin had reduced Enterobacterium spp. compared with pigs offered the control diet. However, the combination of laminarin and fucoidan had increased Enterobacterium spp. compared with alone. Pigs offered diets containing fucoidan had increased Lactobacilli spp. in the proximal colon (P < 0.05) and distal colon (P < 0.001) compared with non‐fucoidan diets. CONCLUSION: Overall, the reductions in intestinal Enterobacterium spp. and increases in Lactobacilli spp. obtained suggest that laminarin and fucoidan may provide a dietary means to improve gut health in pigs. Copyright © 2009 Society of Chemical Industry