Design and Fabrication of a Polymer FDM Printer Capable of Build Parameter Monitoring and In-Sit Geometric Monitoring Via Photogrammetry

Additive manufacturing, or 3D printing, is a complex process that creates free-form geometric objects by sequentially placing material in a location to construct an object, usually as a layer-by-layer process. One of the most widespread methods is Fused Deposition Modeling (FDM). FDM is used in many of the consumer-grade polymer 3D printers available today. While consumer grade machines are cheap and plentiful, they lack many of the features desired in a machine used for research purposes and are often closed-source platforms. Commercial-grade models are more expensive and are also usually closed-source platforms that do not offer flexibility for modifications often needed for research. This research focuses on the design and fabrication of a machine to be used as a test bed for research in the field of polymer FDM processes. The goal was to create a platform that tightly controls and/or monitors the FDM build parameters so that experiments can be repeated with a known accuracy. The platform offers closed loop position feedback, control of the hot end and bed temperature, and monitoring of environment temperature and humidity. Additionally, the platform is equipped with cameras and a mechanism for in-situ photogrammetry, creating a geometric record of the print throughout the printing process. Through photogrammetry, backtracking and linking of process parameters to observable geometric defects can be achieved. The controls system and instrumentation are built on an open flexible paradigm enabling customization as necessary for future research

Natural History Of Syphilitic Aortitis

No large studies of cardiovascular syphilis at necropsy have been reported since 1964. We examined at necropsy 90 patients who had characteristic morphologic findings of syphilitic aortitis. None had ever undergone cardiovascular surgery. With the exception of 2 cases seen more recently, the hearts and aortas of the 90 patients were examined and categorized by one of us (W.C.R.) from 1966 to 1990. All 90 had extensive involvement of the tubular portion of the ascending aorta by the syphilitic process, which spared the sinuses of Valsalva in all but 4 patients. The aortic arch was also involved in 49 (91%) of 54 patients and the descending thoracic aorta in 47 (90%) of 52 patients. Syphilis was the cause of death in 23 (26%) of the 90 patients. It was secondary to rupture of the ascending or descending thoracic aorta in 12, severe aortic regurgitation leading to heart failure in 10, and severe narrowing of the aortic ostium of the right coronary artery in 1 patient. Of the 40 patients who had undergone serologic testing for syphilis, 28 (70%) had a positive (reactive) finding. Those patients with a negative or nonreactive test or who did not undergo a serologic test for syphilis had morphologic and histologic findings in the aorta at necropsy similar to the findings of those patients who had had a positive serologic test for syphilis. In conclusion, cardiovascular syphilis has not disappeared. In patients with dilated ascending aortas, with or without aortic regurgitation, a serologic test for syphilis is recommended. If the findings are positive or if characteristic morphologic features of cardiovascular syphilis are suspected, irrespective of the results of the serologic tests, antibiotic therapy appears desirable. (C) 2009 Elsevier Inc. All rights reserved. (Am J Cardiol 2009;104:1578-1587)Integrative Biolog

Presence Of A Congenitally Bicuspid Aortic Valve Among Patients Having Combined Mitral And Aortic Valve Replacement

Although bicuspid aortic valve occurs in an estimated 1% of adults and mitral valve prolapse in an estimated 5% of adults, occurrence of the 2 in the same patient is infrequent. During examination of operatively excised aortic and mitral valves because of dysfunction (stenosis and/or regurgitation), we encountered 16 patients who had congenitally bicuspid aortic valves associated with various types of dysfunctioning mitral valves. Eleven of the 16 patients had aortic stenosis (AS): 5 of them also had mitral stenosis, of rheumatic origin in 4 and secondary to mitral annular calcium in 1; the other 6 with aortic stenosis had pure mitral regurgitation (MR) secondary to mitral valve prolapse in 3, to ischemia in 2, and to unclear origin in 1. Of the 5 patients with pure aortic regurgitation, each also had pure mitral regurgitation: in 1 secondary to mitral valve prolapse and in 4 secondary to infective endocarditis. In conclusion, various types of mitral dysfunction severe enough to warrant mitral valve replacement occur in patients with bicuspid aortic valves. A proper search for mitral valve dysfunction in patients with bicuspid aortic valves appears warranted. (C) 2012 Elsevier Inc. All rights reserved. (Am J Cardiol 2012;109:263-271)Integrative Biolog

Perspectives of Dermatology Program Directors on the Impact of Step 1 Pass/Fail.

INTRODUCTION: The shift of Step 1 to Pass/Fail has generated several questions and concerns about obtaining residency positions among allopathic and osteopathic students alike. Determining the perspectives of Dermatology Program Directors in regards to post-Step 1 Pass/Fail is critical for students to better prepare for matching into dermatology. METHODS: After receiving Institutional Review Board (IRB) exemption status, the program directors were chosen from 144 Accreditation Council for Graduate Medical Education (ACGME) and 27 American Osteopathic Association (AOA) Dermatology programs using contact information from their respective online website databases. An eight-item survey was constructed on a three-point Likert scale, one free text response, and four demographic questions. The anonymous survey was sent out over the course of three weeks with weekly individualized reminder requests for participation. RESULTS: A total of 54.54% of responders had Letters of Recommendation in their top 3. Forty-five percent of responders had Completed Audition Rotation at Program in their top 3. And, 38.09% of responders had USMLE Step 2 CK Scores in their top 3. CONCLUSION: Approximately 50% of responders agreed that all medical students will have more difficulty matching dermatology. Based on the survey study, Dermatology program directors want to focus more on letters of recommendation, audition rotations, and Step 2 CK scores. Because each field seems to prioritize different aspects of an application, students should attempt to gain as much exposure to different fields such as through research and shadowing to narrow down their ideal specialties. Consequently, the student will have more time to tailor their applications to what residency admissions are looking for

College students and cyberbullying: how social media use affects social anxiety and social comparison

Cyberbullying is defined as aggression intending to inflict harm on others by electronic communication technologies. Cyberbullying has become more common as social media has grown and is accompanied by negative mental health consequences. Research on cyberbullying and mental health in adolescents suggests cyberbullying victimization moderates the relationship between social comparison and social anxiety, but little is known about this phenomenon in college students. Therefore, the objective of this study was to explore the relationship between cyberbullying, social anxiety, and social comparison amongst college students. A convenience sample of 486 undergraduate students from southern Texas and northern Ohio completed a PyschData survey that assessed social anxiety, social comparison, experiences with be a cyberbullying victim, perpetrator, or both. We found that social anxiety was associated with cyberbullying victimization and perpetration; however, social comparison was not. Cyberbullying victimization was not a moderator between social comparison and anxiety, suggesting that unlike adolescence, college students\u27 experiences with these constructs may be unique to their developmental level

Percent body fat estimations in college men using field and laboratory methods: A three-compartment model approach

Background: Methods used to estimate percent body fat can be classified as a laboratory or field technique. However, the validity of these methods compared to multiple-compartment models has not been fully established. The purpose of this study was to determine the validity of field and laboratory methods for estimating percent fat (%fat) in healthy college-age men compared to the Siri three-compartment model (3C). Methods: Thirty-one Caucasian men (22.5 ± 2.7 yrs; 175.6 ± 6.3 cm; 76.4 ± 10.3 kg) had their %fat estimated by bioelectrical impedance analysis (BIA) using the BodyGram™ computer program (BIA-AK) and population-specific equation (BIA-Lohman), near-infrared interactance (NIR) (Futrex® 6100/XL), four circumference-based military equations [Marine Corps (MC), Navy and Air Force (NAF), Army (A), and Friedl], air-displacement plethysmography (BP), and hydrostatic weighing (HW). Results: All circumference-based military equations (MC = 4.7% fat, NAF = 5.2% fat, A = 4.7% fat, Friedl = 4.7% fat) along with NIR (NIR = 5.1% fat) produced an unacceptable total error (TE). Both laboratory methods produced acceptable TE values (HW = 2.5% fat; BP = 2.7% fat). The BIA-AK, and BIA-Lohman field methods produced acceptable TE values (2.1% fat). A significant difference was observed for the MC and NAF equations compared to both the 3C model and HW (p < 0.006). Conclusion: Results indicate that the BP and HW are valid laboratory methods when compared to the 3C model to estimate %fat in college-age Caucasian men. When the use of a laboratory method is not feasible, BIA-AK, and BIA-Lohman are acceptable field methods to estimate %fat in this population

Interventions in measles outbreaks: the potential reduction in cases associated with school suspension and vaccination interventions

Background: Measles is resurgent in the US, with more cases in 2019 than any year since 1992. Many of the cases were concentrated in three outbreaks in New York and Washington states, where local governments enacted intervention strategies in an attempt to limit the spread of measles. Regulations differed by location, suggesting guidance on the optimal interventions may be beneficial. Methods: We simulate the daily interactions of the populations of six metropolitan areas of Texas, US, using an agent-based model. The real-life vaccination rates of each school in these metropolitan areas are applied to simulated equivalents. A single case of measles is introduced to the population and the resulting number of cases counted. A range of public health interventions, focused on suspending unvaccinated students and mandatory vaccinations, were simulated during measles outbreaks and the reduction in the number of measles cases, relative to no intervention, recorded. Interventions were simulated only in schools with measles cases and in all schools in each metropolitan area. Results: Suspending unvaccinated students from school was associated with the greatest reduction in measles cases. In a plausible worst-case outbreak scenario, the number of cases is forecast to reduce by 68-96%. Interventions targeting all schools in a metropolitan area is not found to be associated with fewer measles cases than only targeting schools with measles cases, at 2018 vaccination rates. Targeting all schools also increases the cumulative number of school days missed by suspended students by a factor of 10-100, depending on the metropolitan area, compared to targeting only schools with measles cases. If vaccination rates drop 5% in the schools which are under-vaccinated in 2018, metropolitan area-wide interventions are forecast to be associated with fewer cases than school-specific interventions. Conclusions: Interventions that are quickly implemented and widely followed may reduce the size of measles outbreaks by up 96%. If vaccination rates continue to fall in Texas, metropolitan area-wide interventions should be considered in the event of an outbreak