The aim of this study was to evaluate the surface topography and the precision measurements of different intraoral and extraoral digital scanners. A reference model of a maxillary arch with four implant analogs was prepared and scanned by three intraoral and two extraoral scanners. The reference model was scanned fifteen times with each digital scanning system, investigating the surface topography and precision measurements for the same-arch and cross-arch measurements. The data was exported to 3D inspection and mesh-processing software (GOM Inspect, Braunschweig, Germany). Statistical analysis was performed using a one-way Analysis of Variance (ANOVA) with the Tukey method for pairwise comparisons. The effect of parameters on generating the surface topography was analyzed by Univariate Linear Regression Analysis. Of the scanner systems evaluated, iTero (IT) exhibited the most number of triangulation points, followed by Trios 3 Shape (TR) and Straumann Cares (SC). There were no significant differences observed in the surface topography when comparing flat and contoured surfaces, the anterior and posterior position, and interproximal areas. For the precision measurement in the same quadrant, no statistical difference was noted between intra- and extraoral scanners. However, the extraoral scanners showed substantially higher precision measurements for the cross-arch measurement. Surface topography did not correlate to precision. Rather, precision correlated with the scanning mechanism. For a quadrant scanning, both intraoral and extraoral scanners are recommended, but extraoral scanners are recommended for a full-arch scanning.

Raw produce has frequently been identified as the source of bacterial pathogens that can cause human illnesses, including listeriosis and salmonellosis. Microbial pathogens may attach and form biofilms on raw fruit surfaces and can be difficult to remove. A cavitation process (injection of bubbles into water) was studied for its effectiveness for removal and inactivation of Listeria monocytogenes and Salmonella Newport from the surfaces of fresh Roma tomatoes and cantaloupes. Individual fruit were separately inoculated with each pathogen, then submerged in a water tank and treated with a bubble flow through an air stone using one airflow rate (0-14 liters/min.) for up to 60 s. As airflow increased, L. monocytogenes reduction on tomato and cantaloupe surfaces increased up to 1.2 and 0.8 log CFU/fruit greater than with water alone (no bubbles), respectively. With a 14 L/min flow rate, Salmonella reduction on tomato and cantaloupe surfaces increased up to 0.9 and 0.7 log CFU/fruit greater than when no bubbles applied, respectively. Also, with the bubble treatments, additional pathogen reduction (detached organisms) was observed in the tank water. Therefore, these bubble streams can be used to enhance the detachment of bacteria from fruit surfaces and to inactivate a proportion of these detached microorganisms. Additionally, recoveries of Salmonella from inoculated Roma tomatoes and cantaloupe were determined for treatment water that contained 50 or 150 ppm sodium hypochlorite. Combining both cavitating bubbles and 150 ppm chlorine in the tank water resulted in greater efficacy of removing or inactivating S. Newport from the surface of cantaloupe (2.9 log CFU) than with cavitation (2.5 log CFU) or chlorine (1.9 log CFU) alone. The physical force of a bubble stream on raw produce can effectively detach and inactivate surface bacteria, and has the potential to reduce antimicrobial chemical use and water use in post-harvest packing operations.

National Security Technologies (NSTec) has developed calibration procedures for X-ray imaging systems. The X-ray sources that are used for calibration are both diode type and diode/fluorescer combinations. Calibrating the X-ray detectors is key to accurate calibration of the X-ray sources. Both energy dispersive detectors and photodiodes measuring total flux were used. We have developed calibration techniques for the detectors using radioactive sources that are traceable to the National Institute of Standards and Technology (NIST). The German synchrotron at Physikalische Technische Bundestalt (PTB) is used to calibrate silicon photodiodes over the energy range from 50 eV to 60 keV.The measurements on X-ray cameras made using the NSTec X-ray sources have included quantum efficiency averaged over all pixels, camera counts per photon per pixel, and response variation across the sensor. The instrumentation required to accomplish the calibrations is described. X-ray energies ranged from 720 eV to 22.7 keV. The X-ray sources produce narrow energy bands, allowing us to determine the properties as a function of X-ray energy. The calibrations were done for several types of imaging devices. There were back illuminated and front illuminated CCD (charge coupled device) sensors, and a CID (charge injection device) type camera. The CCD and CID camera types differ significantly in some of their properties that affect the accuracy of X-ray intensity measurements. All cameras discussed here are silicon based. The measurements of quantum efficiency variation with X-ray energy are compared to models for the sensor structure. Cameras that are not back-thinned are compared to those that are.

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Charge-injection devices (CIDs) are solid-state 2D imaging sensors similar to CCDs, but their distinct architecture makes CIDs more resistant to ionizing radiation.1-3 CID cameras have been used extensively for X-ray imaging at the OMEGA Laser Facility 4,5 with neutron fluences at the sensor approaching 10 9 n/cm 2 (DT, 14 MeV). A CID Camera Xray Imager (CCXI) system has been designed and implemented at NIF that can be used as a rad-hard electronic-readout alternative for time-integrated X-ray imaging. This paper describes the design and implementation of the system, calibration of the sensor for X-rays in the 3 -14 keV energy range, and preliminary data acquired on NIF shots over a range of neutron yields. The upper limit of neutron fluence at which CCXI can acquire useable images is ~ 10 8 n/cm 2 and there are noise problems that need further improvement, but the sensor has proven to be very robust in surviving high yield shots (~ 10 14 DT neutrons) with minimal damage.