Room-temperature ferroelectricity in strained SrTiO3.

Systems with a ferroelectric to paraelectric transition in the vicinity of room temperature are useful for devices. Adjusting the ferroelectric transition temperature (T(c)) is traditionally accomplished by chemical substitution-as in Ba(x)Sr(1-x)TiO(3), the material widely investigated for microwave devices in which the dielectric constant (epsilon(r)) at GHz frequencies is tuned by applying a quasi-static electric field. Heterogeneity associated with chemical substitution in such films, however, can broaden this phase transition by hundreds of degrees, which is detrimental to tunability and microwave device performance. An alternative way to adjust T(c) in ferroelectric films is strain. Here we show that epitaxial strain from a newly developed substrate can be harnessed to increase T(c) by hundreds of degrees and produce room-temperature ferroelectricity in strontium titanate, a material that is not normally ferroelectric at any temperature. This strain-induced enhancement in T(c) is the largest ever reported. Spatially resolved images of the local polarization state reveal a uniformity that far exceeds films tailored by chemical substitution. The high epsilon(r) at room temperature in these films (nearly 7,000 at 10 GHz) and its sharp dependence on electric field are promising for device applications.

Community screening for eye disease by laypersons: the Hoffberger program.

PURPOSE: To describe the results of a community-based eye screening program in Baltimore. DESIGN: Cross-sectional study. METHODS: This was a retrospective study of the results of screening both eyes of 5352 persons who presented at multiple community sites. The screening examination had eight risk factor questions, visual acuity measurement, and a screening field test and was carried out by technicians and lay volunteers. Screened persons (screenees) received a definitive eye examination at no out-of-pocket cost, transportation was offered, and inexpensive eyeglasses were provided if needed. The main outcome measures were the rate of appointment keeping and the eye diseases identified. Telephone interviews were used to assess reasons for missing appointments and satisfaction with visits. RESULTS: Screenees had a median age of 45 years, were 71% black, 59% female, and had estimated median annual family income of 24,000 dollars. Among 1331 screenees who scheduled a definitive examination appointment, 552 (41%) completed the visit. Data on definitive diagnosis was available in 480 out of 552 persons (87%). Reasons given for failing to come for definitive examination were: no appointment given (26%), forgot (20%), lack of transportation (9%), and lack of insurance coverage (6%). Of those who accepted a second visit date after defaulting, only 25% (41/167) appeared. Of 17 persons identified with glaucoma at screening, 4 had previously been diagnosed, but had ceased active care. CONCLUSION: After community screening for eye disease, efforts to provide definitive ophthalmic examination were only modestly effective. Failure of screenees to come for examination and loss to follow up were identified as serious problems.

Augmented bacterial adherence to tracheal epithelial cells is associated with gram-negative pneumonia in an intensive care unit population.

Gram-negative pneumonia is a frequent complication of intubated patients in an intensive care unit (ICU), and the adherence of the bacterial pathogen to the respiratory epithelial surface is thought to be the critical initial step in the infection process. However, the correlation between bacterial adherence to tracheal epithelial cells (TEC) and the acquisition of pneumonia and whether intubation or its duration affects bacterial adherence to TEC is unknown. To examine these factors we initially established that the normal adhesion index range for Pseudomonas aeruginosa strain 492c adherence to TEC was zero to 18.83 cfu/TEC on the basis of the adhesion indices of 12 healthy volunteers and 20 surgical patients undergoing elective bronchoscopy. Forty-two analyses of the adhesion index for P. aeruginosa binding to TEC of 24 ICU patients were performed in this study. Analysis of the data indicated that the adhesion index was not correlated with intubation or the duration of intubation. However, an elevated bacterial adhesion index was significantly (p less than 0.001) correlated with pneumonitis. Pneumonitis was observed in 11 of the 12 patients who had an elevated or augmented bacterial adhesion index, whereas pneumonitis was observed in only one of 12 patients who had a normal adhesion index. The bacterial adhesion index was found to parallel the clinical situation in five patients where three patients developed high adhesion indices and acquired pneumonitis and two patients who initially had pneumonitis and elevated adhesion indices subsequently resolved their pneumonitis, and their adhesion indices fell to within the normal range.

Reinforced heat-processed acrylic resin provisional restorations.

A technique has been described for the fabrication of strong, esthetic, and periodontally considerable provisional restorations. The technique involves cast nonprecious metal frameworks and heat-processed acrylic resin.

Adherence of Pseudomonas aeruginosa to cilia of human tracheal epithelial cells.

Pseudomonas aeruginosa was found to adhere selectively to cilia of human ciliated tracheal epithelial cells (TECs). P. aeruginosa bound in equal numbers to TECs of smokers and nonsmokers, with the mean adhesion index for binding of P. aeruginosa 492c to TECs of healthy individuals (+/- standard deviation) being 6.83 +/- 6.00 bacteria per TEC.