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  • The effect of pore size on cell adhesion in collagen-GAG scaffolds

    O’Brien, F.J.; Harley, B.A.; Yannas, I.V.; Gibson, L.J. (Elsevier, 2005-02)
    The biological activity of scaffolds used in tissue engineering applications hypothetically depends on the density of available ligands, scaffold sites at which specific cell binding occurs. Ligand density is characterized by the composition of the scaffold, which defines the surface density of ligands, and by the specific surface area of the scaffold, which defines the total surface of the structure exposed to the cells. It has been previously shown that collagen–glycosaminoglycan (CG) scaffolds used for studies of skin regeneration were inactive when the mean pore size was either lower than 20 μm or higher than 120 μm (Proc. Natl. Acad. Sci., USA 86(3) (1989) 933). To study the relationship between cell attachment and viability in scaffolds and the scaffold structure, CG scaffolds with a constant composition and solid volume fraction (0.005), but with four different pore sizes corresponding to four levels of specific surface area were manufactured using a lyophilization technique. MC3T3-E1 mouse clonal osteogenic cells were seeded onto the four scaffold types and maintained in culture. At the experimental end point (24 or 48 h), the remaining viable cells were counted to determine the percent cell attachment. A significant difference in viable cell attachment was observed in scaffolds with different mean pore sizes after 24 and 48 h; however, there was no significant change in cell attachment between 24 and 48 h for any group. The fraction of viable cells attached to the CG scaffold decreased with increasing mean pore size, increasing linearly (R2=0.95, 0.91 at 24 and 48 h, respectively) with the specific surface area of the scaffold. The strong correlation between the scaffold specific surface area and cell attachment indicates that cell attachment and viability are primarily influenced by scaffold specific surface area over this range (95.9–150.5 μm) of pore sizes for MC3T3 cells.
  • Activity at the Michigan Cyber Range

    Adams, Joe
    Joe Adams will update a number of Cyber Range activities, including its use in academic courses, a new set of Range hardware at Northern Michigan University, and a Red Team/Blue Team exercise recently conducted in Grand Rapids and Ann Arbor.
  • Interspecies differences in cancer susceptibility and toxicity.

    Hengstler, J G; Van der Burg, B; Steinberg, P; Oesch, F (1999-11-01)
    One of the most complex challenges to the toxicologist represents extrapolation from laboratory animals to humans. In this article, we review interspecies differences in metabolism and toxicity of heterocyclic amines, aflatoxin B1, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and related compounds, endocrine disrupters, polycyclic aromatic hydrocarbons, tamoxifen, and digitoxin. As far as possible, extrapolations to human toxicity and carcinogenicity are performed. Humans may be more susceptible to the carcinogenic effect of heterocyclic amines than monkeys, rats, and mice. Especially, individuals with high CYP1A2 and 3A4 activities and the rapid acetylator phenotype may be expected to have an increased risk. Striking interspecies variation in susceptibility to aflatoxin B1 carcinogenesis is known, with rats representing the most sensitive and mice the most resistant species, refractory to dietary levels three orders of magnitude higher than rats. An efficient conjugation with glutathione, catalyzed by glutathione S-transferase mYc, confers aflatoxin B1 resistance to mice. Extremely large interspecies differences in TCDD-induced toxicity are known. The guinea pig is the most susceptible mammal known, with an LD50 in the range 1-2 micrograms TCDD/kg, whereas the hamster is the most resistant species with an LD50 greater than 3000 micrograms/kg. A number of experts have pointed out to the fact that humans appear to be less sensitive to TCDD than most laboratory animals. Human exposure to background levels of TCDD is not likely to cause an incremental cancer risk. A clear cause--effect relationship has been shown between environmental endocrine-disrupting contaminants and adverse health effects in wildlife, whereas the effects seem to be less critical for humans. Studies on DNA adduct formation and metabolism of the nonsteroidal antiestrogen tamoxifen indicate that rats and mice are orders of magnitude more susceptible than humans.
  • Metadata interoperability in agricultural learning repositories: An analysis

    Nikos, Manouselis (2010-03-01)
    The rapid evolution of ICT creates numerous opportunities for agricultural education and training. Digital learning resources are organized in online databases called learning repositories, in which people can search, locate, and access resources. In order to facilitate the exchange of information between such repositories, the issue of metadata interoperability is crucial. In this paper, we particularly focus on metadata interoperability of learning repositories with content relevant to agricultural stakeholders. More specifically, we present results from an analysis of implementations of metadata standards in agricultural learning repositories around the world. The results provide useful feedback to the developers of repositories with educational content for agricultural stakeholders, as well as directions for potential harmonization of work in this area.
  • Issues and considerations regarding sharable data sets for recommender systems in technology enhanced learning

    Hendrik, Drachsler (2010-01-01)
    This paper raises the issue of missing data sets for recommender systems in Technology Enhanced Learning that can be used as benchmarks to compare different recommendation approaches. It discusses how suitable data sets could be created according to some initial suggestions, and investigates a number of steps that may be followed in order to develop reference data sets that will be adopted and reused within a scientific community. In addition, policies are discussed that are needed to enhance sharing of data sets by taking into account legal protection rights. Finally, an initial elaboration of a representation and exchange format for sharable TEL data sets is carried out. The paper concludes with future research needs.
  • Metadata Principles and Practicalities

    Duval, Erik; Hodgins, Wayne; Sutton, Stuart; Weibel, Stuart L.
    The rapid changes in the means of information access occasioned by the emergence of the World Wide Web have spawned an upheaval in the means of describing and managing information resources. Metadata is a primary tool in this work, and an important link in the value chain of knowledge economies. Yet there is much confusion about how metadata should be integrated into information systems. How is it to be created or extended? Who will manage it? How can it be used and exchanged? Whence comes its authority? Can different metadata standards be used together in a given environment? These and related questions motivate this paper. The authors hope to make explicit the strong foundations of agreement shared by two prominent metadata Initiatives: the Dublin Core Metadata Initiative (DCMI) and the Institute for Electrical and Electronics Engineers (IEEE) Learning Object Metadata (LOM) Working Group. This agreement emerged from a joint metadata taskforce meeting in Ottawa in August, 2001. By elucidating shared principles and practicalities of metadata, we hope to raise the level of understanding among our respective (and shared) constituents, so that all stakeholders can move forward more decisively to address their respective problems. The ideas in this paper are divided into two categories. Principles are those concepts judged to be common to all domains of metadata and which might inform the design of any metadata schema or application. Practicalities are the rules of thumb, constraints, and infrastructure issues that emerge from bringing theory into practice in the form of useful and sustainable systems.
  • Test 2

    Author MR; University of West Tipton (2017-10-03)
  • In-home solid fuel use and cardiovascular disease: a cross-sectional analysis of the Shanghai Putuo study

    Lee, Mi-Sun; Hang, Jing-qing; Zhang, Feng-ying; Dai, He-lian; Su, Li; Christiani, David C; Bundy, CL (2014-01-26)
  • In-home solid fuel use and cardiovascular disease: a cross-sectional analysis of the Shanghai Putuo study

    Lee, Mi-Sun; Hang, Jing-qing; Zhang, Feng-ying; Dai, He-lian; Su, Li; Christiani, David C (2013-09-23)
  • Integrating Biophilic Principles and Therapeutic Design Elements in Outdoor Spaces for Children at Tucson Medical Center

    Davidson, Deryn (The University of Arizona., 2013)
    As concern for the health and wellbeing of children grows in a society geared toward a more sedentary lifestyle, many doctors and therapists are pointing to the importance of access to, and time spent interacting with the natural world. The idea of using the restorative properties of nature in healing has been around since ancient times. There is currently a renaissance in the health care industry looking at the importance of incorporating gardens into the design of health care facilities once again. This project proposes to explore the importance for children in health care facilities to have access to the natural world while using the biophilia hypothesis as a framework for design. Furthermore, the benefits of outdoor areas for the families (particularly siblings) of child patients and the staff of the health care facilities was explored. Through the use of literature and case reviews, data was collected and synthesized to determine the elements best used to strengthen the designs for children’s therapeutic environments. Outcomes include three models of therapeutic environments including focus areas for the Tucson Medical Center campus in Tucson, Arizona.
  • New Life Behind Bars - A Prison Retrofit From Prison to Community Resource

    Machado, Micaela (The University of Arizona., 2013)
    Sustainability practices in design development are a common goal in urban settings, especially in an environment such as the arid Southwest U.S. where resources are limited. Here, sunshine and heat are abundant where water resources are low. So, how can we use these circumstances and constraints to our advantage in future designs or in potential retrofits? Institutional establishments with long-term residents, such as prisons, which use a significant amount of resources can reduce their energy, food and water costs by using sustainable practices. These practices can help reduce the costs of prisoner housing and eventually lower costs to tax payers. This project focuses on a hypothetical retrofit of the Wilmot Department of Corrections (Wilmot D.O.C.) prison facility in Tucson, AZ.
  • Natural Heart: Yangchun Lake Suburban Center Master Plan

    Wang, Yuxin (The University of Arizona., 2013)
    Urbanization in China is rapidly improving with the economic growth. But the development that ignores environment has caused lots of environmental problems in Chinese cities, especially the large ones. As the capital of Hubei Province, Wuhan is the fifth among China cities for its size and its economic production. Because of extreme urbanization and high dense population in Wuhan city, some significant issues have been constantly emerged: lack of adequate wastewater management and water resources protection, urgent need for efficient solution to sludge treatment and disposal, serious urban flooding because of the natural flow or urban lakes and streams restriction, degradation of water quality, and so on. These issues have been seriously impacted the quality life in the city. Along with the urbanization, the conflicts between urban development and ecosystem are inescapable. How can urban development balance environmental sensitivity to support ecological health in the vulnerable urban ecosystem and mitigate the problems in the city? This project tries to redesign a master plan for Yangchun Lake sub-urban center in Wuhan city and find suitable ways to mitigate these problems with attention to the environmental, functional, economic, social and aesthetics aspects of the proposed solutions. The design will balance the urban development and environmental protection, support and enhance the development of a new ecological urban center.
  • Revitalization of Alleys - creating safe, social and green networks in central Tucson

    Zhao, Kexin (The University of Arizona., 2013)
    Alleys are underutilized corridors that can potentially provide many valuable uses in cities. Alleys can be used for multiple purposes during the day and night: conventional functions, dog walking, water harvesting, art display and as renewable energy showcases, to name a few. In addition, they can become welcoming and popular linear gathering spaces. On a grander scale, they can be used as networks and connections between destinations. This project proposes to evaluate the current challenges and opportunities of alleys in central Tucson, to create multiple design templates for safe, social, and green alleys, and to enhance the connectivity to Tucson Modern Streetcar Areas.
  • Theory and Design Considerations of a Saline Ecological Landscape: A constructive method to reduce brine waste volume

    Bresdin, Cylphine (The University of Arizona., 2013)
    Pertinent abiotic and biotic factors and their interdependencies necessary to comprehend the ecology of saline systems are investigated and evaluated. A designed saline ecosystem is proposed as a constructive method to reduce waste volume. Landscape pattern is investigated as the vehicle for an evapotranspiration induced directional saline gradient. A demonstration site is used to explore conceptual design application of the idea of ecosystem pattern consisting of a linear sequence of ecotopes, each displaying its own ecological community in relation to salinity range and site context. Biota is relinquished to self-organization. Potential for research use of the ecosystem is illustrated.
  • Identifying Potential Candidate SNP's and Genes Linked to Handedness for Future Study

    Takyar, Ankit (The University of Arizona., 2012)
    The goal was to identify genes for future study that might be linked to handedness for potential candidate gene study. We were able to find 3 major genes through statistically analyzing SNP data within a Genome-wide association Statistical Analysis tool, PLINK. 27 SNPs were chosen based on P-values of below .001, further analysis was done to these 27 SNPs to figure out their gene locus. Using NCBI we found 21 SNPs were within a gene locus. A total of 16 genes were found from the 21 SNPs that were located within a gene locus. Three extra genes were examined since they were located in a gene of interest CTNNA2. The genes found were further screened for high expression in subcortical regions and that have been implicated in neural function or brain development. Out of the 17 genes determined, IRAK2, NRG1, and CTNNA2 adhered to the criteria for screening.
  • Antifungal Compounds Produced in Antagonistic Competition Between Marine Fungi

    Tariq, Muhammad Buchan (The University of Arizona., 2012)
    Competition among fungi has been characteristic of antibiotic relationships between microbes, leading to the discovery of novel antimicrobial compounds. This study observed such antagonistic relationships between marine fungi isolated from coral off the coast of Woods Hole, Massachusetts. Competition assays were conducted on these fungal isolates against two chosen competing species on PDA plates. Three fungal isolates were observed to release antifungal compounds inhibiting the growth of the competing species. Methanol extracts were taken from each of the three fungal isolates and ¹H and ¹³C NMR spectra obtained. The three fungi were shown to produce antifungal compounds, not observed in previous studies. 14 fractions were obtained from subjecting the methanol extracts from each of the three fungi to chromatography. The final step remains to test these fractions for antifungal activity leading to the isolation and identification of the antifungal compounds.

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