Evaluation of energy absorption of new concepts of aircraft composite subfloor intersections

Forty-one composite aircraft subfloor intersection specimens were tested to determine the effects of geometry and material on the energy absorbing behavior, failure characteristics, and post-crush structural integrity of the specimens. The intersections were constructed of twelve ply + or - 45 sub 6 laminates of either Kevlar 49/934 or AS-4/934 graphite-epoxy in heights of 4, 8, and 12 inches. The geometry of the specimens varied in the designs of the intersection attachment angle. Four different geometries were tested

A Study of Visual Fixation

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Electron tomography of late stages of FcRn-mediated antibody transcytosis in neonatal rat small intestine

The neonatal Fc receptor (FcRn) transports maternal immunoglobulin (IgG) across epithelia to confer passive immunity to mammalian young. In newborn rodents, FcRn transcytoses IgG from ingested milk across the intestinal epithelium for release into the bloodstream. We used electron tomography to examine FcRn transport of Nanogold-labeled Fc (Au-Fc) in neonatal rat jejunum, focusing on later aspects of transport by chasing Au-Fc before fixation. We observed pools of Au-Fc in dilated regions of the lateral intercellular space (LIS), likely representing exit sites where Au-Fc accumulates en route to the blood. Before weaning, the jejunum functions primarily in IgG transport and exhibits unusual properties: clathrin-rich regions near/at the basolateral LIS and multivesicular bodies (MVBs) expressing early endosomal markers. To address whether these features are related to IgG transport, we examined LIS and endocytic/transcytotic structures from neonatal and weaned animals. Weaned samples showed less LIS-associated clathrin. MVBs labeled with late endosomal/lysosomal markers were smaller than their neonatal counterparts but contained 10 times more internal compartments. These results are consistent with hypotheses that clathrin-rich basolateral regions in neonatal jejunum are involved in IgG exocytosis and that MVBs function in IgG transport while FcRn is expressed but switch to degradative functions after weaning, when the jejunum does not express FcRn or transport IgG

Structure of a Pheromone Receptor-Associated MHC Molecule with an Open and Empty Groove

Neurons in the murine vomeronasal organ (VNO) express a family of class Ib major histocompatibility complex (MHC) proteins (M10s) that interact with the V2R class of VNO receptors. This interaction may play a direct role in the detection of pheromonal cues that initiate reproductive and territorial behaviors. The crystal structure of M10.5, an M10 family member, is similar to that of classical MHC molecules. However, the M10.5 counterpart of the MHC peptide-binding groove is open and unoccupied, revealing the first structure of an empty class I MHC molecule. Similar to empty MHC molecules, but unlike peptide-filled MHC proteins and non-peptide–binding MHC homologs, M10.5 is thermally unstable, suggesting that its groove is normally occupied. However, M10.5 does not bind endogenous peptides when expressed in mammalian cells or when offered a mixture of class I–binding peptides. The F pocket side of the M10.5 groove is open, suggesting that ligands larger than 8–10-mer class I–binding peptides could fit by extending out of the groove. Moreover, variable residues point up from the groove helices, rather than toward the groove as in classical MHC structures. These data suggest that M10s are unlikely to provide specific recognition of class I MHC–binding peptides, but are consistent with binding to other ligands, including proteins such as the V2Rs

Analysis of the Space Shuttle Orbiter skin panels under simulated hydrodynamic loads

The Space Shuttle orbiter skin panels were analyzed under pressure loads simulating hydrodynamic loads to determine their capability to sustain a potential ditching and to determine pressures that typically would produce failures. Two Dynamic Crash Analysis of Structures (DYCAST) finite element models were used. One model was used to represent skin panels (bays) in the center body, while a second model was used to analyze a fuselage bay in the wing region of the orbiter. From an assessment of the DYCAST nonlinear computer results, it is concluded that the probability is extremely high that most, if not all, of the lower skin panels would rupture under ditching conditions. Extremely high pressure loads which are produced under hydrodynamic planning conditions far exceed the very low predicted failure pressures for the skin panels. Consequently, a ditching of the orbiter is not considered to have a high probability of success and should not be considered a means of emergency landing unless no other option exists

Characterizing middle and secondary preservice teachers' change in inferential reasoning

Title from PDF of title page (University of Missouri--Columbia, viewed on October 18, 2012).The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file.Dissertation advisor: Dr. James E. TarrVita.Ph. D. University of Missouri--Columbia 2011."May 2011"This study characterizes how a cohort of 33 middle and secondary mathematics preservice teachers' inferential reasoning changed while enrolled in a statistics course designed for future teachers. Changes in inferential reasoning from pre- to postassessments are analyzed and further elucidated by midcourse clinical interviews conducted with a stratified random sample of 12 participants. Using a modified SOLO taxonomy (Biggs & Collis, 1982, 1989), the average dominant level of inferential reasoning for the cohort shifted from Unistructural to Multistructural over the course. While 58% of all participants increased their level of inferential reasoning, growth wasmore pronounced for secondary preservice teachers. A relationship between informal and formal approaches to inferential tasks was determined as 80% of levels assigned to formal inferential task responses were concordant with the dominant informal inferential reasoning level. Classification of course tasks revealed an increased demand for adaptive reasoning with the introduction of formal inferential methods.Includes bibliographical reference

The preservation of atmospheric nitrate in snow at Summit, Greenland

There is great interest in using nitrate NO3 isotopic composition in ice cores to track the history of precursor nitrogen oxides (NOx = NO + NO2) in the atmosphere. Nitrate NO3 however can be lost from the snow by surface processes, such as photolysis back to NOx upon exposure to sunlight, making it difficult to interpret records of NO3 as a tracer of atmospheric NOx loading. In a campaign consisting of two field seasons (May–June) at Summit, Greenland, high temporal frequency surface snow samples were collected and analyzed for the oxygen isotopic composition of NO3. The strong, linear relationship observed between the oxygen isotopes of NO3 in both 2010 and 2011, is difficult to explain in the presence of significant post depositional processing of NO3 unless several unrelated variables change in concert. Therefore, the isotopic signature of NO3 in the snow at Summit is most feasibly explained as preserved atmospheric NO3 deposition

Review of Tobacco Policies on University of California Campuses

Background and Purpose: College and university tobacco control programs have historically neglected cessation. In 2012, the University of California Office of the President (UCOP) released a Smoke and Tobacco Free policy that became effective in January 2014. The policy provided for a comprehensive education and outreach campaign that included resources and referrals for cessation. We sought to determine whether all University of California (UC) campuses met UCOP standards. Methods: We reviewed the Smoke & Tobacco Free policies created by UCOP and posted at ten UC campuses, searched the tobacco free websites of each campus for cessation resources, and contacted tobacco-free task forces. Results: We found that all UC campuses met the UCOP standard by addressing tobacco cessation in their campus policies. The provision of cessation services and resources was limited and varied substantially by campus, and no campuses reported collecting data on the use of cessation programs. Conclusion: Consistent with concerns that college and university tobacco policies neglect cessation, UC campuses mentioned tobacco cessation resources and programs but did not provide consistent services. These campuses also did not report on the use of tobacco cessation resources, making it difficult to assess the effects of offering different types of cessation programs

An overview of the crash dynamics failure behavior of metal and composite aircraft structures

An overview of failure behavior results is presented from some of the crash dynamics research conducted with concepts of aircraft elements and substructure not necessarily designed or optimized for energy absorption or crash loading considerations. Experimental and analytical data are presented that indicate some general trends in the failure behavior of a class of composite structures that includes fuselage panels, individual fuselage sections, fuselage frames, skeleton subfloors with stringers and floor beams without skin covering, and subfloors with skin added to the frame stringer structure. Although the behavior is complex, a strong similarity in the static/dynamic failure behavior among these structures is illustrated through photographs of the experimental results and through analytical data of generic composite structural models

Cholesterol hemi­methanol solvate

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73458/1/S1600536801020487.pd