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

Factors Affecting Hay Supply and Demand in Tennessee

Understanding the interactions between supply and demand for hay is important because of hay’s significance to the agricultural sector and economy, and because hay is an important crop on highly erodible soils. As an example, Tennessee has the most erodible cultivated cropland in the United States (Denton, 2000), nearly half of the state’s current CRP acreage contracts are set to expire in 2007 (U.S. Department of Agriculture, 2006), and hay is one of the most economically important crops produced in the state (U.S. Department of Agriculture, 2004). Cross (1999) attributed the upward trend in Tennessee hay acreage since 1980 to an increasing number of farmers who were searching for alternative production activities, such as hay, pasture and livestock, to replace row crops on erodible soils (U.S. Congress, House of Representatives and Senate, 2002). Hay ranked tenth in value of receipts in Tennessee at $49.25 million in 2006 and cattle and calf production ranked first at$500 million. Hay ranked second in value of production at $262 million in 2003 and averaged$248 million over a five period from 2002 – 2006. Underscoring the importance of hay in Tennessee was the state’s national ranking of fourth in the production of other hay (excluding alfalfa) at 4.25 million tons in 2006 (U.S. Department of Agriculture, 2007). To quantify these supply and demand relationships, one must understand the characteristics of hay markets. Markets are usually localized because of the weight and bulky physical characteristics of hay. Although hay species are not identical, in many livestock production situations most are close substitutes, with the possible exception of alfalfa hay. In Tennessee, alfalfa is a differentiated hay product used mostly by dairy and equine producers. Nevertheless, alfalfa constituted only 2.5% of all hay produced in Tennessee in 2003 (U.S. Department of Agriculture, 2004) and its price tends to move proportionally with other hay prices; thus, for modeling purposes alfalfa and other hay can be aggregated as in Shumway’s (1983) study of Texas field crops and treated as a composite commodity (Nicholson, 2005) called hay. In 2002, 47,000 operations within the state produced forage, while on the demand side, 50,000 operations were involved in beef and dairy production with another 24,000 equine operations (U.S. Department of Agriculture, 2004). Despite the lack of national and state central markets for hay (Cross, 1999), buyers and sellers seem to be aware of the current prices in their area. Word of mouth, a hay directory website (Tennessee Farm Bureau Federation, 2005), and the Farm Facts bulletin (Tennessee Agricultural Statistics Service, 2004) are among the primary outlets for price discovery (Rawls, September 2004). Hay producers are typically assumed to be price takers (Shumway, 1983) because of the large numbers of sellers and buyers; nevertheless, search costs and price differentials can result from the lack of a central market. Even though hay and livestock producers have avenues for price determination in the short run, they have little information about what causes supply and demand for hay to change from year to year. The overall objective of this research was to illustrate how the understanding of hay markets can provide valuable information to hay and livestock producers and agricultural policymakers. Using the Tennessee hay market as an example, the specific objectives were to: 1) determine the factors that influence Tennessee hay supply and quantify their effects, 2) determine the factors that influence Tennessee hay demand and quantify their effects, and 3) briefly illustrate the importance of hay supply and demand information to policymakers. Estimating factors that influence hay supply and demand can help to provide hay and livestock producers with valuable information for making more informed business decisions and policymakers with insight into how proposed agricultural policies might affect hay and livestock producers. To accomplish the objectives, Tennessee hay supply and demand were modeled econometrically, and the coefficients of the models were used to quantify hay acreage, yield, and price responses to the factors that influence the Tennessee hay market. The results were then used to briefly illustrate the potential impacts on the 2008 Tennessee hay price from the retirement of Conservation Reserve Program (CRP) acreage in 2007. Hay acreage proved to be fairly unresponsive to output and input prices in both the short and long runs. The weak response of hay acreage to own and substitute crop prices may result from many hay producers also being cattle producers that harvest their own hay in an effort to guarantee a reliable supply of roughage to feed their herds throughout the winter months. They might be willing to give up potentially higher profits from a production alternative to avert the risk of feed shortages for their cattle. The hay price appeared to be responsive to real per capita income with a price flexibility of 1.55. This finding is reasonable because an increase in real per capita income results in more purchasing power for a typical household. As purchasing power increases, one would expect beef consumption to increase because beef is a normal good (Schroeder and Mark, 1999). Increased beef consumption would positively influence the derived demand for beef production inputs; hence, increased demand for hay. A weak response of hay price to the quantity of hay produced (HPRODt) could be explained by the hay market structure. First, some livestock farmers may produce large amounts of hay for their own livestock, much of which is not sold on the market. These farmers may be able to produce hay at a lower cost than market price, or they may be willing to forgo the potential cost savings from buying hay from an off-farm source to avert the risk of feed shortages for their cattle. Additionally, unlike the market for corn or cattle, the hay market is much less organized and structured. Farmers producing hay for the cash market have no nearby and convenient grain elevator or auction market at which to sell their product. Weak response to changes in hay quantity and price suggests that hay farmers may not be driven solely by the profit motive. Instead, other motives may also enter into their objective functions as utility maximizers.acreage response, derived demand, elasticities, hay, inverse demand function, price flexibilities, yield response, Crop Production/Industries, Demand and Price Analysis, D,

Effect Of Coronary Bypass And Valve Structure On Outcome In Isolated Valve Replacement For Aortic Stenosis

Reports differ regarding the effect of concomitant coronary artery bypass grafting (CABG) in patients who undergo aortic valve replacement (AVR) for aortic stenosis (AS), and no reports have described the effect of aortic valve structure in patients who undergo AVR for AS. A total of 871 patients aged 24 to 94 years (mean 70) whose AVR for AS was their first cardiac operation, with or without first concomitant CABG, were included. Patients who underwent mitral valve procedures were excluded. In comparison with the 443 patients (51%) who did not undergo CABG, the 428 (49%) who underwent concomitant CABG were significantly older, were more often male, had lower transvalvular peak systolic pressure gradients and larger valve areas, had lower frequencies of congenitally malformed aortic valves, had lighter valves by weight, had higher frequencies of systemic hypertension, and had longer stays in the hospital after AVR. Early and late (to 10 years) mortality were similar by propensity-adjusted analysis in patients who did and did not undergo concomitant CABG. Congenitally unicuspid or bicuspid valves occurred in approximately 90% of those aged 21 to 50, in nearly 70% in those aged 51 to 70 years, and in just over 30% in those aged 71 to 95 years. Unadjusted and adjusted survival was significantly higher in patients with unicuspid or bicuspid valves compared to those with tricuspid valves. In conclusion, although concomitant CABG had no effect on the adjusted probability of survival, the type of aortic valve (unicuspid or bicuspid vs tricuspid) significantly affected the unadjusted and adjusted probability of survival. (C) 2012 Elsevier Inc. All rights reserved. (Am J Cardiol 2012;109:1334-1340)Statistic

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