Fabrication of a Definitive CAD/CAD Titanium Abutment Prior to Guided Surgery: A Pilot Study

Purpose: The purpose of this prospective comparative study is to determine the possibility of designing a CAD/CAM patient specific abutment that reproducibly predicts the clinical relationship of the abutment/crown interface with the peri-implant mucosal margin. Materials and Methods: Seventeen patients were allocated to 2 groups of subgingival abutment margin depths: 1.5mm and 0.5mm. A surgical guide, custom abutment and provisional crown were fabricated prior to surgery. Implants were placed in 16 participants using a guided surgery protocol. Results: Five of the sixteen abutments had abutment margin exposure at abutment delivery. Four of the five abutment margin exposures occurred at molar sites. Ten out of sixteen provisional crowns fit with zero adjustment. Conclusions: The results of this pilot study suggest that the digital workflow of producing a definitive titanium abutment and milled provisional crown prior to guided surgery is initially successful. Abutment Margin Exposure is more likely in molar sites.Master of Scienc

Comparison of Ejecta Distributions from Normal Incident Hypervelocity Impact on Lunar Regolith Simulant

The National Aeronautics and Space Administration (NASA) is progressing toward long-term lunar habitation. Critical to the design of a lunar habitat is an understanding of the lunar surface environment; of specific importance is the primary meteoroid and subsequent ejecta environment. The document, NASA SP-8013, was developed for the Apollo program and is the latest definition of the ejecta environment. There is concern that NASA SP-8013 may over-estimate the lunar ejecta environment. NASA's Meteoroid Environment Office (MEO) has initiated several tasks to improve the accuracy of our understanding of the lunar surface ejecta environment. This paper reports the results of experiments on projectile impact into powered pumice and unconsolidated JSC-1A Lunar Mare Regolith stimulant (JSC-1A) targets. The Ames Vertical Gun Range (AVGR) was used to accelerate projectiles to velocities in excess of 5 km/s and impact the targets at normal incidence. The ejected particles were detected by thin aluminum foil targets placed around the impact site and angular distributions were determined for ejecta. Comparison of ejecta angular distribution with previous works will be presented. A simplistic technique to characterize the ejected particles was formulated and improvements to this technique will be discussed for implementation in future tests

Model-Based Systems Engineering and F’: Proof of Concept Via the Creation of an On-Orbit Textual Command Parsing Component for the ABEX Mission

The Alabama Burst Energetics eXplorer (ABEX) mission is defining spacecraft architecture, behavior, mission phases, operational states, risks, and requirements in a Model-Based Systems Engineering (MBSE) Integrated Systems Model (ISM) using SysML in Cameo Enterprise Architecture (CEA). The satellite structural design can be exported from CEA as Extensible Markup Language (XML) specifications and imported to F’, an open-source Flight Software (FSW) framework from NASA’s Jet Propulsion Laboratory. F’ contains background components intended to be connected to user-defined components in the XML after it is exported from the ISM; in this work, ABEX is representing F’ background components in SysML Internal Block Diagrams from which the XML is generated. As a proof of concept for this MBSE-centric FSW implementation, the ABEX FSW team has created a Command Reader component from MBSE-generated XML and tested command enaction on a Raspberry Pi breadboard system for three test cases representing on-orbit command triggers

Accuracy of ED Bedside Ultrasound for Identification of gallstones: retrospective analysis of 575 studies

Study Objective: To determine the ability of emergency department (ED) physicians to diagnose cholelithiasis with bedside ultrasound. Methods: ED gallbladder ultrasounds recorded over 37 months were compared to radiology ultrasound interpretation. Results: Of 1,690 ED gallbladder ultrasound scans performed during this period, radiology ultrasound was performed in 575/1690 (34%) cases. ED physician bedside interpretation was 88% sensitive [95% CI, 84-91] and 87% specific [95% CI, 82-91], while positive predictive value (PPV) was 91% [88- 94%] and negative predictive value (NPV) was 83% [78-87%], using radiology interpretation as the criterion reference. Conclusion: ED physician ultrasound of the gallbladder for cholelithiasis is both sensitive and specific

Educational Assessment of Medical Student Rotation in Emergency Ultrasound

Background: Medical student ultrasound education is sparse. In 2002, we began the first medical student rotation in emergency ultrasound. Objective: To evaluate if medical students can learn and retain sonographic skills during a two- or four-week elective. Methods: We gave students an exam on the first and last days of the rotation. Six months later, students took the exam a third time. A control group was used for comparison. Results: Over a 19-month period, we enrolled 45 students (25 on the two-week and 20 on the four-week elective). The four-week student post-test score was significantly better than the two- week posttest score (81% vs. 72%, p=0.003). On the six-month exam, the four-week student post-test score was significantly better than the two-week post-test score (77% vs 69%, p=0.008). The control group did not statistically improve. Conclusion: Medical students can learn bedside ultrasound interpretation with clinical integration and retain the knowledge six months later

The Colombian and Venezuelan republics, with notes on other parts of Central and South America,

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Case of Venezuela : brief concerning the question of boundary between Venezuela and British Guiana /

Mode of access: Internet