Final design of the beam source for the MITICA injector.

The megavolt ITER injector and concept advancement experiment is the prototype and the test bed of the ITER heating and current drive neutral beam injectors, currently in the final design phase, in view of the installation in Padova Research on Injector Megavolt Accelerated facility in Padova, Italy. The beam source is the key component of the system, as its goal is the generation of the 1 MeV accelerated beam of deuterium or hydrogen negative ions. This paper presents the highlights of the latest developments for the finalization of the MITICA beam source design, together with a description of the most recent analyses and R&D activities carried out in support of the design.

Management of patients needing antibiotic prophylaxis in a dental education setting.

The management of antibiotic prophylaxed (ABX) patients at an educational institution was evaluated to identify areas for improvement. Management criteria, reflecting guidelines to prevent oral-induced hematogenous microbial seeding, were pretested and applied to 1,225 record entries of eighty-five patients needing ABX for dental treatment between 1991 and 1996. Seven hundred twenty-two of the visits had 857 management or documentation problems, including no documentation indicating whether or not patients premedicated (n = 281); incomplete, insufficient, or repeated treatment (n = 214); and preventive concerns (n = 172), among others. The proportion of providers' patient visits with one or more management problems differed significantly (p < 0.001) by provider type, as did the distribution of problem categories (documentation, treatment, preventive, and scheduling concerns p < 0.001; compliance issues p < 0.005). Fifty-one percent of postgraduates' and 39 percent of faculty's record entries omitted patients' ABX status. Improved documentation, outcome measures, and patient, faculty and student education are indicated.

Improving the oral hygiene of institutionalized mentally retarded clients.

PURPOSE: The quality of oral health care of persons with mental retardation has been reported in the literature to be less than that of their normal peers. The purpose of this study, set in a Midwest institution for persons with developmental retardation, was to determine if a change in policy followed by staff training and monitored by an interested third party would improve the oral hygiene of clients living on wards. METHODS: Methods used to train staff in proper toothbrushing were developed. Three living units were randomly selected for study: control, training plus accountability (experimental group I), and training without accountability (experimental group II). The direct care staff of both experimental groups were trained in proper toothbrushing techniques. Staff of the control group received no training. A dental hygienist visited the living unit periodically to evaluate and provide feedback on the plaque index scores taken by the caregivers in both experimental groups. RESULTS: The plaque indexes of group I showed significant improvement over the control group and group II. CONCLUSION: The results of this pilot study support the other findings of higher plaque indexes for residents with mental retardation and that modifying toothbrushing policies and staff training are not as critical to the improvement of the clients' oral hygiene as is the presence of an involved, interested third party.

Sjögren's syndrome: a challenge for dentistry.

Sjögren's syndrome presents dentists with many challenges, from diagnosis to therapy. The secondary effects of xerostomia cause a spectrum of oral problems, including caries, candidal infection, and inflammation of the oral mucosa. The oral signs and symptoms may be the first manifestations of systemic aspects of the disease. Sjögren's syndrome requires both dental and medical management, and a program of home care.

Retention of cemented implant-supported restorations.

PURPOSE: This investigation compared cement failure loads of a gold cylinder luted to a CeraOne titanium abutment (5-mm-high chimney) 24 hours postcementation when either zinc phosphate, Tempbond NE, or Tempbond luting agent was used. MATERIALS AND METHODS: Luting agent (0.01 mL) was applied to the internal aspect of the gold cylinder, and the cylinder was seated with finger pressure followed by a load of 5 kg for 10 minutes. The specimens were stored in 100% humidity at 37 degrees C for 24 hours before a uniaxial tensile force was applied to the gold cylinder by a mechanical testing instrument. A load-displacement chart was plotted and the cement failure load (CFL) calculated in kilograms. CFLs were determined for each luting agent with the access opening for the CeraOne gold screw on the internal of the abutment either unfilled or filled with autopolymerizing resin. RESULTS: A two-way ANOVA and Turkey's HSD revealed that zinc phosphate resulted in significantly higher (p < .05) mean CFLs than Tempbond or Tempbond NE. In general, filling the access opening did not affect mean CFLs for zinc phosphate and Tempbond NE. However, mean CFLs for gold cylinders cemented with Tempbond and a filled access opening were significantly higher than mean CFLs with an unfilled access opening. However, neither the filled nor the unfilled Tempbond group mean CFL was significantly different from either Tempbond NE mean CFL. CONCLUSIONS: Twenty-four hours postcementation, zinc phosphate luting cement significantly enhanced CFLs of a CeraOne gold cylinder luted to a 5-mm CeraOne titanium abutment compared with Tempbond and Tempbond NE. Filling the gold screw access opening of the abutment with autopolymerizing resin only led to higher mean CFLs when Tempbond was used as the luting agent. Filling the access opening had no effect (p > .05) on mean CFLs when Tempbond NE or zinc phosphate was used.

Numerical simulation of the signal and data processing of the HIPPARCOS satellite.

This paper presents a theoretical study of the diffraction pattern which will be obtained with the telescope launched aboard the HIPPARCOS satellite. The output signal is studied by simulating observations of various stars of different spectral types and classes. In the case of very faint stars, the signal will consist of only a few photons during a sampling interval, so that a statistical recovery of the signal will be needed. A simulation of such a signal is described. The last part of this paper deals with the data processing.