Switching "on" and "off" the adhesion in stimuli-responsive elastomers.

The present work aims at the preparation of dry adhesives with switchable bonding properties by using the reversible nature of the [4πs+4πs] cycloaddition of anthracenes. Photo-responsive hydrogenated carboxylated nitrile butadiene rubber with photo-responsive pendant anthracene groups is prepared by one-pot synthesis. The formation of 3D networks relies on the photodimerization of the anthracene moieties upon UV exposure (λ > 300 nm). Controlled cleavage of the crosslink sites is achieved by either deep UV exposure (λ = 254 nm) or thermal dissociation at 70 °C. The kinetics of the optical and thermal cleavage routes are compared in thin films using UV-vis spectroscopy and their influence on the reversibility of the network is detailed. Going from thin films to free standing samples the modulation of the network structure and thermo-mechanical properties over repeated crosslinking and cleavage cycles are characterized by low-field NMR spectroscopy and dynamic mechanical analysis. The applicability of the stimuli-responsive networks as adhesives with reversible bonding properties is demonstrated. The results evidence that the reversibility of the crosslinking reaction enables a controlled switching "on" and "off" of adhesion properties. The recovery of the adhesion force amounts to 75 and 80% for photo- and thermal dissociation, respectively. Spatial control of adhesion properties is evidenced by adhesion force mapping experiments of photo-patterned films.

Quality of care at a children's hospital: the parent's perspective.

OBJECTIVES: To develop a measure of parental perceptions of pediatric inpatient quality of care, to identify processes of care that influence these perceptions, and to describe these perceptions of care. DESIGN: An interdisciplinary team modified an existing measure of inpatient care for adults using focus groups and expert review. The resulting survey was administered by telephone. SETTING: Tertiary care pediatric hospital. PATIENTS: Trained telephone interviewers obtained reports from parents of children discharged from the hospital during specified months. This report is based on the answers to 122 questions provided by 3622 (77%) of 4724 parents who responded when surveyed from 1991 through 1995. MAIN OUTCOME MEASURES: Parents provided reports about specific clinical experiences, overall ratings of care, and patient demographic and illness characteristics 2 weeks after patient discharge from the hospital. The analysis classified reports about pediatric care as either problems or not problems. Problems in different areas of care were averaged to create scores for the dimensions. RESULTS: Parents most often noted problems related to hospital discharge planning (18%) and pain management (18%) and less often reported problems concerning communication about surgery (10%) or transmission of information to children (6%). Problems in communication between clinicians and parents correlated most strongly with overall quality ratings by parents (r=0.59). Parents' specific reports of problems with care accounted for 42% of the variation in their overall assessments of the inpatient care experience. CONCLUSIONS: Parental assessment of inpatient pediatric care rests heavily on the quality of communication between the clinician and parent. Specific processes of care strongly influence overall assessments. Such reports could be used to focus the quality-improvement activities of hospitals and increase the accountability of providers of care to children and families.

Sensitivity of patient report of care to organizational change.

Patient report of care is a popular outcome measure believed to be sensitive to nursing care and institutional changes that effect the delivery of nursing care. However, data collected over a 5-year period of organizational change in a pediatric teaching hospital showed no change in parent report of care. The authors discuss possible reasons for the absence of change and caution readers that patient report of care should not be the sole measure of the effect of restructuring on patients.

Biotransformation of ellipticine into 5-formyl ellipticine by Choisya ternata strains.

Sixteen Choisya ternata strains of same genotypic origin were examined for their capacities to biotransform ellipticine. Four strains were able to convert the drug into 5-formylellipticine with good yields. The reaction occurred only in agar medium and was different from ellipticine bioconversion by microorganisms or mammals.