Influence of molecular architecture on the dewetting of thin polystyrene films

The control of dewetting for thin polymer films is a technical challenge and of significant academic interest. We have used polystyrene nanoparticles to inhibit dewetting of high molecular weight, linear polystyrene, demonstrating that molecular architecture has a unique effect on surface properties. Neutron reflectivity measurements were used to demonstrate that the nanoparticles were uniformly distributed in the thin (ca. 40 nm) film prior to high temperature annealing, yet after annealing, they were found to separate to the solid substrate, a silanized silicon wafer. Dewetting was eliminated when the nanoparticles separated to form a monolayer or above while below this surface coverage the dewetting dynamics was severely retarded. Blending linear polystyrene of similar molecular weight to the polystyrene nanoparticle with the high molecular weight polystyrene did not eliminate dewetting.

The hot can: ICD failure presenting as severe shoulder pain

We describe a patient whose presentation of ICD generator failure was excruciating shoulder pain lasting 3 hours. This painful episode prompted evaluation and subsequent generator replacement. Destructive analysis of the explanted device revealed a short circuit of three battery filter capacitors, which resulted in the battery "dumping" its full energy very rapidly, since the impedance across the battery terminal was < 1 ohm. The duration of the painful episode was equal to the estimated ICD battery life under this low impedance condition.

Outcomes of a cardiovascular nutrition counseling program in African-Americans with elevated blood pressure or cholesterol level

OBJECTIVE

To evaluate a cardiovascular nutrition education package designed for African-American adults with a wide range of literacy skills.

DESIGN

Comparison of a self-help group and a full-instruction group; each group received nutrition counseling and clinical monitoring every 4 months.

SUBJECTS

Three hundred thirty African-American adults, aged 40 to 70 years, with elevated cholesterol level or high blood pressure were randomly assigned to the self-help or full-instruction group; 255 completed the 12-month follow-up.

INTERVENTIONS

Counseling to reduce intake of dietary fat, cholesterol, and sodium was based on Cardiovascular Dietary Education System (CARDES) materials, which included food-picture cards, a nutrition guide (self-help and full-instruction group), a video and audiotape series, and 4 classes (full-instruction group only).

MAIN OUTCOME MEASURES

Changes in lipid levels and blood pressure after 12 months.

STATISTICAL ANALYSES PERFORMED

Primary analyses consisted of repeated-measures analysis of variance to examine effects of time and randomization group on outcomes.

RESULTS

Total cholesterol and low-density lipoprotein cholesterol level decreased by 7% to 8% in the self-help and full-instruction groups of men and women (P < .01). The ratio of total cholesterol to high-density lipoprotein cholesterol (HDL-C) decreased in both groups of women and in the men in the full-instruction group (P < .01). In full-instruction and self-help participants with elevated blood pressure at baseline, systolic blood pressure decreased by 7 to 11 mm Hg and diastolic blood pressure decreased by 4 to 7 mm Hg (P < .01). Outcomes did not differ by literacy scores but were positively related to the reported initial frequency of using CARDES materials.

APPLICATIONS/CONCLUSIONS

These results suggest that periodic nutrition counseling based on CARDES materials used for home study can enhance management of lipid levels and blood pressure in African-American outpatients.

Literacy assessment in a cardiovascular nutrition education setting

We assessed functional literacy of hypercholesterolemic or hypertensive African Americans (n = 339) prior to their participation in a nutrition education program. A word pronunciation and recognition test using 20 common cardiovascular or nutrition terms was first developed based on correlations with standardized reading achievement test scores, then administered to program participants. Nearly half (48%) had word recognition scores equivalent to a < or = 8th grade reading level. Lower scores were associated with less education, lower income, unemployment, heavier work activity if employed, less healthy diets, history of heart disease or diabetes, and higher depression scores (all P < 0.01); several of these associations were independent of education. The educational materials were geared to a 5th to 8th grade reading level. However, when both audiotaped and printed instruction were provided, individuals with reading scores < or = 8th grade preferentially used the tapes. This brief and relatively unobtrusive literacy assessment may help to identify persons who can benefit most from audiovisual approaches to cardiovascular nutrition education.