230 research outputs found
Recommended from our members
Topical timolol for treatment of persistent granulation tissue in the setting of severe hidradenitis suppurativa
Hidradenitis suppurativa (HS) is a potentially debilitating dermatological disease that negatively impacts patients' quality of life. Severe cases can be further complicated by persistent granulation tissue at the ostia of sinus tracts, which may prove recalcitrant to standard interventions. Herein we report such a case in which a patient experienced significant improvement from severe HS but was left with persistent granulation tissue that complicated his course of recovery. When standard interventions failed, we elected to begin treatment with topical timolol. After three months, the majority of the granulation tissue had regressed and has remained quiescent after 12 months of follow up. The patient has tolerated the treatment well and continues to use topical timolol daily as needed for flares. We believe that topical timolol can provide a practical and painless alternative to current invasive and expensive therapies for persistent granulation tissue associated with severe HS
Nitrous oxide as a substitute for sulfur hexafluoride in the ANSI/ASHRAE 110 Method of hood performance evaluation
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 39-40).The ANSI/ASHRAE 110 Method is the standard test for laboratory hood containment performance. Sulfur hexafluoride is specified as the gas most suitable for this test and is most commonly used. Sulfur hexafluoride use has potential negative environmental repercussions as it is a potent greenhouse gas with a global warming potential 22,800 times greater per mass than CO₂. The purpose of this study is to evaluate nitrous oxide, a much less environmentally destructive tracer gas, as a potential substitute in the ANSI/ASHRAE 110 Method. In accordance with ANSI standards, flow visualization, face velocity, and tracer gas tests were performed on numerous laboratory hoods of varying design. A mannequin was positioned in front of the center of the hood, and a MIRAN SapphlRe was used to measure the presence of each tracer gas. Direct comparisons of the concentrations of the two gases were dominated by a few high concentrations. For this reason, concentrations of both gases were log1O-transformed for statistical analyses. Laboratory hood dimensions and properties were found to affect the relationship between the gases. The hood area of opening and sash height were found to significantly (p<0.001) affect logjo(SF₆/ N₂O). Average face velocity also significantly (p<0.025) affected the log ratio. Neither gas was an adequate indicator of the behavior of the other. The linear best fit of the logs of the concentration ratio had a slope of 0.858, a y-intercept of 0.434, and an R² of 35.9% indicating a poor correlation. For N₂O to qualify as a substitute for SF6 there would need to be a strong correlation between gas concentrations that was consistent independently of hood conditions. This condition was not met. Nitrous oxide was found to not be a suitable substitute for sulfur hexafluoride in the ANSI/ASHRAE 110 Method.by Eric J. Guffey.S.B
Development Of The EGGS Exam Of GeoloGy Standards To Measure Students’ Understanding Of Common Geology Concepts
Geoscience education researchers have considerable need for criterion-referenced, easy-to-administer, easy-to-score, conceptual surveys for undergraduates taking introductory science survey courses in order for faculty to monitor the learning impacts of innovative teaching. In response, this study establishes the reliability and validity of a 28-item, multiple-choice, pre- and post- EGGS Exam of GeoloGy Standards. EGGS addresses 11 concepts derived from a systematic analysis of the overlapping ideas from national science education reforms: NGSS, AAAS Benchmarks, Earth Science Literacy Principles, and NRC National Science Education Standards. Leveraging best-practices for creating and field-testing items, EGGS emphasizes natural student language over technical scientific vocabulary, leverages illustrations over students’ reading ability, specifically targets students’ misconceptions, and covers the range of topics most geology educators expect general education students to know. EGGS is argued to be valid and reliable with college introductory science survey students based on standard measures, including clinical interviews with students and expert review
Opt-In Project Explores Uncharted Planning Territory in Southwestern NC
“We’re closer to five other state capitals than we are to Raleigh.” That’s a phrase you’re likely to hear within the first five minutes of a conversation with leaders in the far western region of western North Carolina. Although it may sound like a simple observation on geography, the obstacles our isolated location and rugged terrain create for regional planners and economic developers means that any attempt at a collaborative regional vision is likely to strain the limited capacities of existing governments and institutions. This is a difficult task, even in large metropolitan areas with plenty of leaders and resources to draw on. It is doubly so in a sparsely populated, rural region like ours. These challenges are why the Opt-In SWNC visioning initiative is so unique and so important. The initiative’s ambitions are to fill in research gaps, identify opportunities, and test alternative strategies to inform decision-making about economic development, transportation planning and the environment in the far western North Carolina counties
Surveying Geology Concepts In Education Standards For A Rapidly Changing Global Context
Internationally much attention is being paid to which of a seemingly endless list of scientific concepts should be taught to schoolchildren to enable them to best participate in the global economy of the 21st Century. In regards to science education, the concepts framing the subject of geology holds exalted status as core scientific principles in the Earth and space sciences domain across the globe. Economic geology plays a critical role in the global economy, historical geology guides research into predictions related by global climate change, and environmental geology helps policy makers understand the impact of human enterprises on the land, among many other geological sciences-laden domains. Such a situation begs the question of which geology concepts are being advocated in schools. Within the U.S. where there is no nationally adopted curriculum, careful comparative analysis reveals surprisingly little consensus among policy makers and education reform advocates about which geology concepts, if any, should be included in the curriculum. This lack of consensus manifests itself in few traditional or modern geology concepts being taught to U.S. school children
Hypoglycaemia and hyperglycaemia are associated with unfavourable outcome in infants with hypoxic ischaemic encephalopathy:a post hoc analysis of the CoolCap Study
Combined 624-nm and 850-nm illumination at low rates leads to enhanced inhibition of Candida albicans
Background: To determine whether combinations of red and infrared light could improve inhibition of Candida albicans and whether combining wavelengths and altering rate of energy delivery could prevent the formation of resistance to light energy.Methods: C. albicans was tested because of the common appearance in human skin and mucous membrane infections. The organism was treated in vitro with a combination of 624-nm (red) and 850-nm (infrared) light emitted from a supraluminous diode (SLD) array. Doses of 9, and 30 J/cm2 were used. Rate of energy delivery was also manipulated. Colony counts were performed and compared to untreated controls using Student t tests and one-way ANOVA with Tukey post hoc analysis.Results: The combination of 624 and 850-nm light energy at 30 J/cm2 was an effective (p ≤ 0.05) inhibitor of C. albicans across all seven stages of the experiment. The combination of 624 and 850-nm wavelengths produced a maximum kill rate [{control – treated / control} X 100] of 76.24% and an average kill rate of 54% across the seven stages of the experiment.Conclusions: A Combination of 624-nm and 850-nm light from an SLD array can inhibit the growth of C. albicans in vitro. Altering delivery rate of the energy can delay resistance formation in this organism.
Sub-lunar Tap Yielding eXplorer (STYX) & Surface Telemetry Operations and Next-generation Excavation System (STONES)
The NASA RASC-AL Moon to Mars competition challenges student teams to develop a lightweight, durable, and hands-off method for extracting water from Martian/lunar subsurface ice layers while mapping soil density profiles. Future interplanetary expeditions are dependent on the availability of clean water and this project aims to accomplish this task. The challenge description enumerates several criteria to be met for successful designs. For further information, the STYX & STONES team conducted research on Cal Poly’s competition project from last year to consider the areas for redesign. As such, the team has utilized the background research from relevant patents and journal articles to consider brainstorming potentially viable solutions. Based on these solutions for each subsystem, the team converged the ideas using a series of decision matrices into a final design direction.
In addition to reviewing the STYX design, several new considerations were made for the scope of this project. Primarily, this year’s team focused on developing a prototype that has the capability of operating in an extraterrestrial environment and thoroughly fulfilling the requirements posed by NASA. To visualize the requirements, the team created a list of customer needs, a House of Quality diagram, and an engineering specifications table. Additionally, the STYX & STONES team discussed the design process it plans to follow including major project milestones. Specifically, the team plans to excel in collecting more than five quarts of water autonomously while successfully identifying the overburden layers – tasks that previous teams have struggled with.
The team’s design direction includes two main components: a masonry drill bit and an auger- heater probe hybrid tool. The masonry drill bit will create a hole in the overburden using the force from a rotary hammer. The heater probe tool will then be moved to align with the hole and be driven into the loosened overburden using the force of a small gear motor. The heater probe will then melt ice using a hot waterjet and deliver water via a peristaltic pump and a two-stage filtration system.
To verify the design, the team completed a multitude of analyses and tests for each subsystem and the prototype as a whole. Through drilling tests, the team found that the rotary hammer and masonry bit can easily cut through all overburden layers while keeping weight on bit (WOB) below 150N. Similarly, the load cells attached to the drill carriage were tested and proven to be accurate at recording WOB data and providing feedback to the controller to monitor WOB. Furthermore, the load cells proved successful at recording accurate WOB data that can be analyzed to determine overburden composition. The pumping system was also tested and was capable of effectively moving water through all filters and delivering fluid to the waterjet. More tests were completed to verify the heater probe tool; these tests included controlling heater temperature, melting ice, expelling water through the waterjet, and removing loose material from the hole.
To verify the design requirements, the team has completed analysis pertaining to each subsystem including the drill, heater probe, frame, and control systems. The team is confident in the drilling
design based on testing and vibrations analysis. In the same manner, the team verified that the 12V peristaltic pump will have enough pressure head rise based on analysis and prototype testing. Using the prototype heater probe as a reference, the team fully characterized the heat transfer parameters of the final design and is confident the auger will be effective considering surrounding debris. Finally, the team tested the water jet design using 120oF water which provided optimistic results that the water jet will significantly expand the melt radius per hole. As a next step, the team will be testing the mechanical and controls systems simultaneously using manufactured parts. The following report details the subsystems and relevant information
- …