Surface deterioration of dental materials after simulated toothbrushing in relation to brushing time and load.

OBJECTIVES: (1) To evaluate the changes in surface roughness and gloss after simulated toothbrushing of 9 composite materials and 2 ceramic materials in relation to brushing time and load in vitro; (2) to assess the relationship between surface gloss and surface roughness. METHODS: Eight flat specimens of composite materials (microfilled: Adoro, Filtek Supreme, Heliomolar; microhybrid: Four Seasons, Tetric EvoCeram; hybrid: Compoglass F, Targis, Tetric Ceram; macrohybrid: Grandio), two ceramic materials (IPS d.SIGN and IPS Empress polished) were fabricated according to the manufacturer's instructions and optimally polished with up to 4000 grit SiC. The specimens were subjected to a toothbrushing (TB) simulation device (Willytec) with rotating movements, toothpaste slurry and at three different loads (100g/250g/350g). At hourly intervals from 1h to 10h TB, mean surface roughness Ra was measured with an optical sensor and the surface gloss (Gl) with a glossmeter. Statistical analysis was performed for log-transformed Ra data applying two-way ANOVA to evaluate the interaction between load and material and load and brushing time. RESULTS: There was a significant interaction between material and load as well as between load and brushing time (p<0.0001). The microhybrid and hybrid materials demonstrated more surface deterioration with higher loads, whereas with the microfilled resins Heliomolar and Adoro it was vice versa. For ceramic materials, no or little deterioration was observed over time and independent of the load. The ceramic materials and 3 of the composite materials (roughness) showed no further deterioration after 5h of toothbrushing. Mean surface gloss was the parameter which discriminated best between the materials, followed by mean surface roughness Ra. There was a strong correlation between surface gloss and surface roughness for all the materials except the ceramics. The evaluation of the deterioration curves of individual specimens revealed a more or less synchronous course suspecting hinting specific external conditions and not showing the true variability in relation to the tested material. SIGNIFICANCE: The surface roughness and gloss of dental materials changes with brushing time and load and thus results in different material rankings. Apart from Grandio, the hybrid composite resins were more prone to surface changes than microfilled composites. The deterioration potential of a composite material can be quickly assessed by measuring surface gloss. For this purpose, a brushing time of 10h (=72,000 strokes) is needed. In further comparative studies, specimens of different materials should be tested in one series to estimate the true variability.

Motor Vehicle Accident Fatalities for the Week Ending, January 26, 2007

Record of the Fatalities for Motor Vehicle Accidents in Iowa per week.

Motor Vehicle Accident Fatalities for the Week Ending, December 29, 2006

Record of the Fatalities for Motor Vehicle Accidents in Iowa per week.

Flexible Fuel Vehicle Report, 2007

House File 2754 requires by February 1 of each year the Iowa Department of Transportation shall deliver a report to the governor and legislative services agency regarding flexible fuel vehicles registered in Iowa.

Motor Vehicle Accident Fatalities for the Week Ending, January 19, 2007

Record of the Fatalities for Motor Vehicle Accidents in Iowa per week.

Evaporation from a shallow water table: Diurnal dynamics of measured and simulated water and heat regime at the vicinity of a drying sand surface

Accurate estimates of water losses by evaporation from shallow water tables are important for hydrological, agricultural, and climatic purposes. An experiment was conducted in a weighing lysimeter to characterize the diurnal dynamics of evaporation under natural conditions. Sampling revealed a completely dry surface sand layer after 5 days of evaporation. Its thickness was <1 cm early in the morning, increasing to reach 4?5 cm in the evening. This evidence points out fundamental limitations of the approaches that assume hydraulic connectivity from the water table up to the surface, as well as those that suppose monotonic drying when unsteady conditions prevail. The computed vapor phase diffusion rates from the apparent drying front based on Fick's law failed to reproduce the measured cumulative evaporation during the sampling day. We propose that two processes rule natural evaporation resulting from daily fluctuations of climatic variables: (i) evaporation of water, stored during nighttime due to redistribution and vapor condensation, directly into the atmosphere from the soil surface during the early morning hours, that could be simulated using a mass transfer approach and (ii) subsurface evaporation limited by Fickian diffusion, afterward. For the conditions prevailing during the sampling day, the amount of water stored at the vicinity of the soil surface was 0.3 mm and was depleted before 11:00. Combining evaporation from the surface before 11:00 and subsurface evaporation limited by Fickian diffusion after that time, the agreement between the estimated and measured cumulative evaporation was significantly improved.

Investigation Into the Timeliness of the Death Notification to the Surviving Spouse of a Motor Vehicle Accident Victim, 2005

Report: #05-02 Kirke C. Quinn, Attorney for Jo Anne Holland, first contacted the Ombudsman by letter dated January 2, 2004. Quinn also addressed his letter to the Governor’s Office, Iowa State Patrol (ISP), and Iowa Department of Public Safety (DPS). Quinn characterized his letter as a complaint against ISP regarding “the method and manner of reporting the death of Ross Holland to his surviving spouse.” According to Quinn, Mrs. Holland “went through hours of misery as a result of the patrol’s inattention to a tragic situation.” On January 7, 2004, the Ombudsman asked ISP Major Gary Hoskins, Supervisor of Field Operations, how ISP and DPS intended to respond to Mr. Quinn’s letter. Major Hoskins stated he would refer Quinn’s letter of complaint to DPS’ Professional Standards Bureau (PSB) for investigation and response. After speaking with Major Hoskins, the Ombudsman told Mr. Quinn that DPS would do an internal investigation and if he were not satisfied with the results he could contact the Ombudsman again. On March 29, 2004, Mr. Quinn contacted the Ombudsman and stated he was not satisfied with DPS’ response. Quinn stated he would send a copy of the response to the Ombudsman, along with a letter stating his outstanding issues and concerns. In his letter to the Ombudsman, dated May 5, Quinn simply stated: “Please find enclosed [a] copy of the letter received from the Department of Public Safety. We think this is an absolute outrage. We welcome your input.”

Motor Vehicle Accident Fatalities for the Week Ending, February 9, 2007

Record of the Fatalities for Motor Vehicle Accidents in Iowa per week.

Motor Vehicle Accident Fatalities for the Week Ending, February 16, 2007

Record of the Fatalities for Motor Vehicle Accidents in Iowa per week.

Motor Vehicle Accident Fatalities for the Week Ending, March 2, 2007

Record of the Fatalities for Motor Vehicle Accidents in Iowa per week.

Motor Vehicle Accident Fatalities for the Week Ending, February 23, 2007

Record of the Fatalities for Motor Vehicle Accidents in Iowa per week.

Combined transesophageal and surface MRI provides optimal imaging in aortic atherosclerosis.

OBJECTIVE: Surface magnetic resonance imaging (MRI) for aortic plaque assessment is limited by the trade-off between penetration depth and signal-to-noise ratio (SNR). For imaging the deep seated aorta, a combined surface and transesophageal MRI (TEMRI) technique was developed 1) to determine the individual contribution of TEMRI and surface coils to the combined signal, 2) to measure the signal improvement of a combined surface and TEMRI over surface MRI, and 3) to assess for reproducibility of plaque dimension analysis. METHODS AND RESULTS: In 24 patients six black blood proton-density/T2-weighted fast-spin echo images were obtained using three surface and one TEMRI coil for SNR measurements. Reproducibility of plaque dimensions (combined surface and TEMRI) was measured in 10 patients. TEMRI contributed 68% of the signal in the aortic arch and descending aorta, whereas the overall signal gain using the combined technique was up to 225%. Plaque volume measurements had an intraclass correlation coefficient of as high as 0.97. CONCLUSION: Plaque volume measurements for the quantification of aortic plaque size are highly reproducible for combined surface and TEMRI. The TEMRI coil contributes considerably to the aortic MR signal. The combined surface and TEMRI approach improves aortic signal significantly as compared to surface coils alone. CONDENSED ABSTRACT: Conventional MRI aortic plaque visualization is limited by the penetration depth of MRI surface coils and may lead to suboptimal image quality with insufficient reproducibility. By combining a transesophageal MRI (TEMRI) with surface MRI coils we enhanced local and overall image SNR for improved image quality and reproducibility.

Motor Vehicle Accident Fatalities for the Week Ending, March 9, 2007

Record of the Fatalities for Motor Vehicle Accidents in Iowa per week.

Motor Vehicle Accident Fatalities for the Week Ending, March 16, 2007

Record of the Fatalities for Motor Vehicle Accidents in Iowa per week.

Oligopotent stem cells are distributed throughout the mammalian ocular surface.

The integrity of the cornea, the most anterior part of the eye, is indispensable for vision. Forty-five million individuals worldwide are bilaterally blind and another 135 million have severely impaired vision in both eyes because of loss of corneal transparency; treatments range from local medications to corneal transplants, and more recently to stem cell therapy. The corneal epithelium is a squamous epithelium that is constantly renewing, with a vertical turnover of 7 to 14 days in many mammals. Identification of slow cycling cells (label-retaining cells) in the limbus of the mouse has led to the notion that the limbus is the niche for the stem cells responsible for the long-term renewal of the cornea; hence, the corneal epithelium is supposedly renewed by cells generated at and migrating from the limbus, in marked opposition to other squamous epithelia in which each resident stem cell has in charge a limited area of epithelium. Here we show that the corneal epithelium of the mouse can be serially transplanted, is self-maintained and contains oligopotent stem cells with the capacity to generate goblet cells if provided with a conjunctival environment. Furthermore, the entire ocular surface of the pig, including the cornea, contains oligopotent stem cells (holoclones) with the capacity to generate individual colonies of corneal and conjunctival cells. Therefore, the limbus is not the only niche for corneal stem cells and corneal renewal is not different from other squamous epithelia. We propose a model that unifies our observations with the literature and explains why the limbal region is enriched in stem cells.