63 research outputs found
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Altering temperature in a mammalian body
The present application relates to systems and methods for altering temperature in a mammalian body. Optionally, the systems and methods can be used to lower or raise core body temperature of a mammalian subject. Optionally, the systems and methods can be used to lower or raise the temperature of glabrous skin of a mammalian subject.Board of Regents, University of Texas Syste
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Development and Transfer of Innovative Problem Solving Strategies and Related Confidence in Biomedical Engineering
Twenty-nine biomedical engineering (BME) undergraduates participated in a challenge-based instruction biotransport course, offered by the UT Austin BME Department in an accelerated format, at the University of Cambridge. Students’ attitudes toward, and aptitude for solving genuine and complex biomedical problems were assessed throughout the semester through surveys, interviews, observations, and in-class examinations. Students’ aptitude for problem solving improved throughout the semester, in a manner independent of content knowledge development. By the end of the semester, students readily transferred the problem-solving framework, learned within a biotransport context, to solve biomechanics problems. Additionally, we observed significant increases over time in students’ confidence in their ability to complete challenges within and outside of the biotransport domain. We believe that this illustrative case study provides significant quantitative evidence supporting the effectiveness of challenge-based pedagogies for engineering courses.Cockrell School of Engineerin
Measurement and mathematical modeling of thermally induced injury and heat shock protein expression kinetics in normal and cancerous prostate cells.
Abstract Purpose: Hyperthermia can induce heat shock protein (HSP) expression in tumours, which will cause enhanced tumour viability and increased resistance to additional thermal, chemotherapy, and radiation treatments. The study objective was to determine the relationship of hyperthermia protocols with HSP expression kinetics and cell death and develop corresponding computational predictive models of normal and cancerous prostate cell response. Methods: HSP expression kinetics and cell viability were measured in PC3 prostate cancer and RWPE-1 normal prostate cells subjected to hyperthermia protocols of 44 to 60 C for 1 to 30 min. Hsp27, Hsp60, and Hsp70 expression kinetics were determined by western blotting and visualised with immunofluorescence and confocal microscopy. Based on measured HSP expression data, a mathematical model was developed for predicting thermally induced HSP expression. Cell viability was measured with propidium iodide staining and flow cytometry to quantify the injury parameters necessary for predicting cell death following hyperthermia. Results: Significant Hsp27 and Hsp70 levels were induced in both cell types with maximum HSP expression occurring at 16 h post-heating, and diminishing substantially after 72 h. PC3 cells were slightly more sensitive to thermal stress than RWPE-1 cells. Arrhenius analysis of injury data suggested a transition between injury mechanisms at 54 C. HSP expression and injury models were effective at predicting cellular response to hyperthermia. Conclusion: Measurement of thermally induced HSP expression kinetics and cell viability associated with hyperthermia enabled development of thermal dosimetry guidelines and predictive models for HSP expression and cell injury as a function of thermal stress to investigate and design more effective hyperthermia therapies
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The effects of habitat, climate, and Barred Owls on long-term demography of Northern Spotted Owls
Estimates of species' vital rates and an understanding of the factors affecting those parameters over time and space can provide crucial information for management and conservation. We used mark–recapture, reproductive output, and territory occupancy data collected during 1985–2013 to evaluate population processes of Northern Spotted Owls (Strix occidentalis caurina) in 11 study areas in Washington, Oregon, and northern California, USA. We estimated apparent survival, fecundity, recruitment, rate of population change, and local extinction and colonization rates, and investigated relationships between these parameters and the amount of suitable habitat, local and regional variation in meteorological conditions, and competition with Barred Owls (Strix varia). Data were analyzed for each area separately and in a meta-analysis of all areas combined, following a strict protocol for data collection, preparation, and analysis. We used mixed effects linear models for analyses of fecundity, Cormack-Jolly-Seber open population models for analyses of apparent annual survival (ϕ), and a reparameterization of the Jolly-Seber capture–recapture model (i.e. reverse Jolly-Seber; RJS) to estimate annual rates of population change (λ[subscript]RJS) and recruitment. We also modeled territory occupancy dynamics of Northern Spotted Owls and Barred Owls in each study area using 2-species occupancy models. Estimated mean annual rates of population change (λ) suggested that Spotted Owl populations declined from 1.2% to 8.4% per year depending on the study area. The weighted mean estimate of λ for all study areas was 0.962 (± 0.019 SE; 95% CI: 0.925–0.999), indicating an estimated range-wide decline of 3.8% per year from 1985 to 2013. Variation in recruitment rates across the range of the Spotted Owl was best explained by an interaction between total winter precipitation and mean minimum winter temperature. Thus, recruitment rates were highest when both total precipitation (29 cm) and minimum winter temperature (−9.5°C) were lowest. Barred Owl presence was associated with increased local extinction rates of Spotted Owl pairs for all 11 study areas. Habitat covariates were related to extinction rates for Spotted Owl pairs in 8 of 11 study areas, and a greater amount of suitable owl habitat was generally associated with decreased extinction rates. We observed negative effects of Barred Owl presence on colonization rates of Spotted Owl pairs in 5 of 11 study areas. The total amount of suitable Spotted Owl habitat was positively associated with colonization rates in 5 areas, and more habitat disturbance was associated with lower colonization rates in 2 areas. We observed strong declines in derived estimates of occupancy in all study areas. Mean fecundity of females was highest for adults (0.309 ± 0.027 SE), intermediate for 2-yr-olds (0.179 ± 0.040 SE), and lowest for 1-yr-olds (0.065 ± 0.022 SE). The presence of Barred Owls and habitat covariates explained little of the temporal variation in fecundity in most study areas. Climate covariates occurred in competitive fecundity models in 8 of 11 study areas, but support for these relationships was generally weak. The fecundity meta-analysis resulted in 6 competitive models, all of which included the additive effects of geographic region and annual time variation. The 2 top-ranked models also weakly supported the additive negative effects of the amount of suitable core area habitat, Barred Owl presence, and the amount of edge habitat on fecundity. We found strong support for a negative effect of Barred Owl presence on apparent survival of Spotted Owls in 10 of 11 study areas, but found few strong effects of habitat on survival at the study area scale. Climate covariates occurred in top or competitive survival models for 10 of 11 study areas, and in most cases the relationships were as predicted; however, there was little consistency among areas regarding the relative importance of specific climate covariates. In contrast, meta-analysis results suggested that Spotted Owl survival was higher across all study areas when the Pacific Decadal Oscillation (PDO) was in a warming phase and the Southern Oscillation Index (SOI) was negative, with a strongly negative SOI indicative of El Niño events. The best model that included the Barred Owl covariate (BO) was ranked 4th and also included the PDO covariate, but the BO effect was strongly negative. Our results indicated that Northern Spotted Owl populations were declining throughout the range of the subspecies and that annual rates of decline were accelerating in many areas. We observed strong evidence that Barred Owls negatively affected Spotted Owl populations, primarily by decreasing apparent survival and increasing local territory extinction rates. However, the amount of suitable owl habitat, local weather, and regional climatic patterns also were related to survival, occupancy (via colonization rate), recruitment, and, to a lesser extent, fecundity, although there was inconsistency in regard to which covariates were important for particular demographic parameters or across study areas. In the study areas where habitat was an important source of variation for Spotted Owl demographics, vital rates were generally positively associated with a greater amount of suitable owl habitat. However, Barred Owl densities may now be high enough across the range of the Northern Spotted Owl that, despite the continued management and conservation of suitable owl habitat on federal lands, the long-term prognosis for the persistence of Northern Spotted Owls may be in question without additional management intervention. Based on our study, the removal of Barred Owls from the Green Diamond Resources (GDR) study area had rapid, positive effects on Northern Spotted Owl survival and the rate of population change, supporting the hypothesis that, along with habitat conservation and management, Barred Owl removal may be able to slow or reverse Northern Spotted Owl population declines on at least a localized scale.Keywords: Northern Spotted Owl,
occupancy,
population change,
Strix varia,
Strix occidentalis caurina,
fecundity,
Barred Owl,
surviva
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Freezing/perfusion microscope stage
This invention relates to a microscope stage assembly for use in combination with magnification apparatus. The stage assembly includes a support assembly, temperature control assembly and fluid control assembly. The stage assembly provides for continuous visual observation of an object being magnified while at the same time controlling the thermal and fluid environment of the object. Physical and chemical changes to an object can be viewed continuously.Board of Regents, University of Texas Syste
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