Analysis of SiC technology in two-level and three-level converters for aerospace applications

There is a growing need for highly efficient, power dense DC-AC converters to support a number of future more electric aircraft technologies. SiC has been identified as a potential technology to improve the efficiency of these converters. To analyse the semiconductor losses, this paper presents the semiconductor loss equations for the two-level converter (2LC), three-level neutral point clamped converter (3LNPCC) and the three-level T-Type converter (3LTTC). Based on the equations and current datasheet information, it is identified that SiC technology offers significant reductions in losses compared with traditional Si devices. The paper also discusses a number of hybrid device combinations to achieve the benefits of high efficiency in SiC technology and low cost of Si technology. Based on the semiconductor losses the converter efficiencies in the SiC 2LC and the 3LTTCs are about 3-4 % higher than in the Si 2LC for a 42 kW three phase converter operating at a 25 kHz switching frequency

Imaging correlates of molecular signatures in oligodendrogliomas.

Molecular subsets of oligodendroglioma behave in biologically distinct ways. Their locations in the brain, rates of growth, and responses to therapy differ with their genotypes. Retrospectively, we inquired whether allelic loss of chromosomal arms 1p and 19q, an early molecular event and favorable prognostic marker in oligodendrogliomas, were reflected in their appearance on magnetic resonance imaging. Loss of 1p and 19q was associated with an indistinct border on T(1) images and mixed intensity signal on T(1) and T(2). Loss of 1p and 19q was also associated with paramagnetic susceptibility effect and with calcification, a common histopathological finding in oligodendrogliomas. These data encourage prospective evaluation of molecular alterations and magnetic resonance imaging characteristics of glial neoplasms

Climate Ready Great Lakes

The Great Lakes region is predicted to experience significant coastal impacts due to global climate change that are different than impacts being predicted for our ocean coasts. Specialized education, training and community planning are needed to assist Great Lakes coastal communities in adapting to changes resulting from climate change. To help address these needs, students from the University of Michigan’s School of Natural Resources and Environment collaborated with NOAA Great Lakes Regional Collaboration team members and Sea Grant professionals to develop training materials on adaptation to climate change in the Great Lakes region. The project resulted in three educational modules that can be delivered individually or as a unit to prepare local officials to develop climate change adaptation plans for their communities: Module 1: “Climate Impacts: What am I Adapting To?” summarizes recent climate change research results and long-term forecasts for climate change impacts. Module 2: “How do I Develop an Adaptation Plan?” prepares leaders to identify and consider management actions necessary to respond to forecasted changes through climate adaptation plans. Module 3: “What Tools are Available for me to Adapt?” familiarizes leaders with decision tools and science based resources needed to make coastal development, resource protection, and infrastructure decisions that that will shape their communities coastline and keep communities sustainable for the next 50-100 years. These outreach modules were developed to allow use by Sea Grant Program Extension Staff, USDA Extension Staff, Coastal Zone Management Programs, and other trained outreach professionals who work with local community decision makers in the Great Lakes region. Modules were designed to allow for maximum flexibility and adaptability and can easily be modified to include future research and tools that increase the information useful for local decision makers.Master of ScienceNatural Resources and EnvironmentUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/83536/1/Climate Ready Great Lakes_April 18 2011.pd

Liquid crystal dimers and the twist-bend nematic phase: on the role of spacers and terminal alkyl chains.

The synthesis and characterisation of four series of liquid crystal dimers based on benzylideneaniline mesogenic units, and in which the lengths of terminal alkyloxy chains are varied are reported. The series differ in terms of their flexible spacers, namely, heptamethylene, nonamethylene, hexyloxy, and oxypentyloxy chains. The heptamethylene- and nonamethylene-linked dimers both show conventional nematic, N, and twist-bend nematic, NTB, phases with short terminal chains, and smectic behaviour emerges on increasing terminal chain length. This is attributed to increased molecular inhomogeneity driving microphase separation. The dimers containing the shorter heptamethylene spacer show a smectic A phase whereas those with the longer nonamethylene spacer exhibit an anticlinic smectic C phase. Smectic behaviour is not observed for the dimers containing either a hexyloxy spacer which exhibit nematic and twist-bend nematic phases, or with an oxypentyloxy spacer which show only a conventional nematic phase. A general observation is that TNTBN and TNI alternate in the same sense in a homologous series on varying the length of the terminal alkyl chains suggesting that the spatial uniformity of the molecular curvature is an important factor in stabilising the NTB phase. The transitional properties of the four corresponding dimers possessing nitrile terminal substituents are also described. These show enantiotropic nematic phases, and in addition, for those containing either polymethylene or hexyloxy spacers, a twist-bend nematic phase is observed. Differences in the thermal behaviour of the dimers may be attributed largely to changes in molecular shape arising from the nature of the link between the spacer and mesogenic units

Soc4425G: Concussion Legacy Foundation Media Creation

Concussion Legacy Foundation Center (CLFC) aims to educated youth in Ontario about concussion awareness and prevention. Our Community Engaged Learning task was to create social media content that would engage and educate youth about concussion in a fun and relevant way. Through the use of a popular social media platform, research, and personal testimonies from youth on their knowledge and interests our group was able to create several videos that inform youths ages 9-14 years old about concussions in a brief, engaging, humorous and fun way

Three-dimensional organotypic co-culture model of intestinal epithelial cells and macrophages to study Salmonella enterica colonization patterns

Three-dimensional models of human intestinal epithelium mimic the differentiated form and function of parental tissues often not exhibited by two-dimensional monolayers and respond to Salmonella in key ways that reflect in vivo infections. To further enhance the physiological relevance of three-dimensional models to more closely approximate in vivo intestinal microenvironments encountered by Salmonella, we developed and validated a novel three-dimensional co-culture infection model of colonic epithelial cells and macrophages using the NASA Rotating Wall Vessel bioreactor. First, U937 cells were activated upon collagen-coated scaffolds. HT-29 epithelial cells were then added and the three-dimensional model was cultured in the bioreactor until optimal differentiation was reached, as assessed by immunohistochemical profiling and bead uptake assays. The new co-culture model exhibited in vivo-like structural and phenotypic characteristics, including three-dimensional architecture, apical-basolateral polarity, well-formed tight/adherens junctions, mucin, multiple epithelial cell types, and functional macrophages. Phagocytic activity of macrophages was confirmed by uptake of inert, bacteria-sized beads. Contribution of macrophages to infection was assessed by colonization studies of Salmonella pathovars with different host adaptations and disease phenotypes (Typhimurium ST19 strain SL1344 and ST313 strain D23580; Typhi Ty2). In addition, Salmonella were cultured aerobically or microaerobically, recapitulating environments encountered prior to and during intestinal infection, respectively. All Salmonella strains exhibited decreased colonization in co-culture (HT-29-U937) relative to epithelial (HT-29) models, indicating antimicrobial function of macrophages. Interestingly, D23580 exhibited enhanced replication/survival in both models following invasion. Pathovar-specific differences in colonization and intracellular co-localization patterns were observed. These findings emphasize the power of incorporating a series of related three-dimensional models within a study to identify microenvironmental factors important for regulating infection

Children's Transport Built Environments: A Mixed Methods Study of Associations between Perceived and Objective Measures and Relationships with Parent Licence for Independent Mobility in Auckland, New Zealand.

Children's independent mobility is declining internationally. Parents are the gatekeepers of children's independent mobility. This mixed methods study investigates whether parent perceptions of the neighbourhood environment align with objective measures of the neighbourhood built environment, and how perceived and objective measures relate to parental licence for children's independent mobility. Parents participating in the Neighbourhood for Active Kids study (n = 940) answered an open-ended question about what would make their neighbourhoods better for their child's independent mobility, and reported household and child demographics. Objective measures of the neighbourhood built environment were generated using geographic information systems. Content analysis was used to classify and group parent-reported changes required to improve their neigbourhood. Parent-reported needs were then compared with objective neighbourhood built environment measures. Linear mixed modelling examined associations between parental licence for independent mobility and (1) parent neighbourhood perceptions; and (2) objectively assessed neighbourhood built environment features. Parents identified the need for safer traffic environments. No significant differences in parent reported needs were found by objectively assessed characteristics. Differences in odds of reporting needs were observed for a range of socio-demographic characteristics. Parental licence for independent mobility was only associated with a need for safer places to cycle (positive) and objectively assessed cycling infrastructure (negative) in adjusted models. Overall, the study findings indicate the importance of safer traffic environments for children's independent mobility

Life-history and spatial determinants of somatic growth dynamics in Komodo dragon populations

Somatic growth patterns represent a major component of organismal fitness and may vary among sexes and populations due to genetic and environmental processes leading to profound differences in life-history and demography. This study considered the ontogenic, sex-specific and spatial dynamics of somatic growth patterns in ten populations of the world\u27s largest lizard the Komodo dragon (Varanus komodoensis). The growth of 400 individual Komodo dragons was measured in a capture-mark-recapture study at ten sites on four islands in eastern Indonesia, from 2002 to 2010. Generalized Additive Mixed Models (GAMMs) and information-theoretic methods were used to examine how growth rates varied with size, age and sex, and across and within islands in relation to site-specific prey availability, lizard population density and inbreeding coefficients. Growth trajectories differed significantly with size and between sexes, indicating different energy allocation tactics and overall costs associated with reproduction. This leads to disparities in maximum body sizes and longevity. Spatial variation in growth was strongly supported by a curvilinear density-dependent growth model with highest growth rates occurring at intermediate population densities. Sex-specific trade-offs in growth underpin key differences in Komodo dragon life-history including evidence for high costs of reproduction in females. Further, inverse density-dependent growth may have profound effects on individual and population level processes that influence the demography of this species