Room-temperature exciton storage in elongated semiconductor nanocrystals.

The excited state of colloidal nanoheterostructures consisting of a spherical CdSe nanocrystal with an epitaxially attached CdS rod can be perturbed effectively by electric fields. Field-induced fluorescence quenching coincides with a conversion of the excited state species from the bright exciton to a metastable trapped state (dark exciton) characterized by a power-law luminescence decay. The conversion is reversible so that up to 10% of quenched excitons recombine radiatively post turn-off of a 1 micro s field pulse, increasing the delayed luminescence by a factor of 80. Excitons can be stored for up to 10(5) times the natural lifetime, opening up applications in optical memory elements.

NO-mediated alterations in skeletal muscle nutritive blood flow and lactate metabolism in fibromyalgia.

UNLABELLED: The purpose of these investigations was to determine if differences exist in skeletal muscle nutritive blood flow and lactate metabolism in women with fibromyalgia (FM) compared to healthy women (HC); furthermore, to determine if differences in nitric oxide-mediated systems account for any detected alterations in blood flow and lactate metabolism and contribute to exertional fatigue in FM. FM (n = 8) and HC (n = 8) underwent a cycle ergometry test of aerobic capacity, a muscle biopsy for determination of nitric oxide synthase (eNOS, nNOS, iNOS) content, and microdialysis for investigation of muscle nutritive blood flow and lactate metabolism. During prolonged (3h) resting conditions, the ethanol outflow/inflow ratio (inversely related to blood flow) increased in FM over time compared to HC (P < 0.05). FM also exhibited a reduced nutritive blood flow response to aerobic exercise (P < 0.05). There was an increase in dialysate lactate in response to acetylcholine in FM, and to sodium nitroprusside in both groups, with a greater rise in dialysate lactate in FM (P < 0.05). The iNOS protein content was higher in FM and was negatively correlated with total exercise time (r(2) = 0.462, P < 0.05). IN CONCLUSION: (1) There is reduced nutritive flow response to aerobic exercise and reduced maximal exercise time in FM that might relate to higher iNOS protein content and contribute to exertional fatigue in FM; (2) The increased dialysate lactate in FM in response to stimulation of NOS or a nitric oxide donor suggest that FM may be more sensitive than HC to the suppressive effect of nitric oxide on oxidative phosphorylation.

Effect of patient reminder/recall interventions on immunization rates: A review.

CONTEXT: Immunization rates for children and adults remain below national goals. While experts recommend that health care professionals remind patients of needed immunizations, few practitioners actually use reminders. Little is known about the effectiveness of reminders in different settings or patient populations. OBJECTIVES: To assess the effectiveness of patient reminder systems in improving immunization rates, and to compare the effectiveness of different types of reminders for a variety of patient populations. DATA SOURCES: A search was performed using MEDLINE, EMBASE, PsychINFO, Sociological Abstracts, and CAB Health Abstracts. Relevant articles, as well as published abstracts, conference proceedings, and files of study collaborators, were searched for relevant references. STUDY SELECTION AND DATA EXTRACTION: English-language studies involving patient reminder/recall interventions (using criteria established by the Cochrane Collaboration) were eligible for review if they involved randomized controlled trials, controlled before-after studies, or interrupted time series, and measured immunization rates. Of 109 studies identified, 41 met eligibility criteria. Studies were reviewed independently by 2 reviewers using a standardized checklist. Results of studies are expressed as absolute percentage-point changes in immunization rates and as odds ratios (ORs). Studies with similar characteristics of patients or interventions were pooled (random effects model). DATA SYNTHESIS: Patient reminder systems were effective in improving immunization rates in 33 (80%) of the 41 studies, irrespective of baseline immunization rates, patient age, setting, or vaccination type. Increases in immunization rates due to reminders ranged from 5 to 20 percentage points. Reminders were effective for childhood vaccinations (OR, 2.02; 95% confidence interval [CI], 1.49-2.72), childhood influenza vaccinations (OR, 4. 25; 95% CI, 2.10-8.60), adult pneumococcus or tetanus vaccinations (OR, 5.14; 95% CI, 1.21-21.78), and adult influenza vaccinations (OR, 2.29; 95% CI, 1.69-3.10). While reminders were most effective in academic settings (OR, 3.33; 95% CI, 1.98-5.58), they were also highly effective in private practice settings (OR, 1.79; 95% CI, 1. 45-2.22) and public health clinics (OR, 2.09; 95% CI, 1.42-3.07). All types of reminders were effective (postcards, letters, and telephone or autodialer calls), with telephone reminders being most effective but costliest. CONCLUSIONS: Patient reminder systems in primary care settings are effective in improving immunization rates. Primary care physicians should use patient reminders to improve immunization delivery. JAMA. 2000;284:1820-1827.