611 research outputs found

    If a Tree Falls in a Roadway, Is Anyone Liable?: Proposing the Duty of Reasonable Care for Virginia’s Road-Maintaining Entities

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    This Note considers whether a duty for road-maintaining entities is tenable under Virginia law. It also explores the rationale for imposing differing liabilities between landowners and road-maintaining entities. Part III reviews the various duties other states use with respect to dangerous roadside trees and concludes that the duty of reasonable care is most appropriate for Virginia. Sovereign immunity is a companion issue and is addressed in Part IV. The Part provides a brief overview of the policy arguments for sovereign immunity, before reviewing immunity’s impact at the state, county, and municipal levels. The Part also addresses a government employee’s entitlement to immunity, before considering a potential legislative solution to some of the present difficulties associated with sovereign immunity. Finally, this Note reviews anticipated impacts in the world of litigation as a result of the duty of reasonable care, before addressing the legal and policy arguments of those who say the impact of such a duty would be negative

    Mechanical properties of cancellous bone

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76183/1/AIAA-1971-111-853.pd

    Elementary Teacher Adaptations to Engineering Curricula to Leverage Student and Community Resources

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    This paper addresses an important consideration for promoting equitable engineering instruction: understanding how teachers contextualize curricular materials to draw upon student and community resources. We present a descriptive case study of two 5th grade teachers who co-designed a Next Generation Science Standards (NGSS)-aligned curricular unit that integrated science, engineering, and computational modeling. The five-week project challenged students to redesign their school grounds to reduce water runoff and increase accessibility for students with disabilities. The teachers implemented the project with one Grade 5 class with a large proportion of students having individualized learning plans and cultural backgrounds minoritized in science, technology, engineering, and mathematics fields. Data sources include classroom videos, teacher interviews, and student artifacts. Findings demonstrate how teachers made helpful, important adaptations to contextualize the curriculum unit and draw upon students’ community-based resources. This case highlights the role of the teacher in enacting engineering materials that privilege student and community resources in elementary classrooms. Findings also underscore the importance of teacher customizations to promote equitable, NGSS-based engineering instruction in elementary classrooms

    Structure–activity relationships of the antimicrobial peptide gramicidin S and its analogs: Aqueous solubility, self-association, conformation, antimicrobial activity and interaction with model lipid membranes

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    AbstractGS10 [cyclo-(VKLdYPVKLdYP)] is a synthetic analog of the naturally occurring antimicrobial peptide gramicidin (GS) in which the two positively charged ornithine (Orn) residues are replaced by two positively charged lysine (Lys) residues and the two less polar aromatic phenylalanine (Phe) residues are replaced by the more polar tyrosine (Tyr) residues. In this study, we examine the effects of these seemingly conservative modifications to the parent GS molecule on the physical properties of the peptide, and on its interactions with lipid bilayer model and biological membranes, by a variety of biophysical techniques. We show that although GS10 retains the largely β-sheet conformation characteristic of GS, it is less structured in both water and membrane-mimetic solvents. GS10 is also more water soluble and less hydrophobic than GS, as predicted, and also exhibits a reduced tendency for self-association in aqueous solution. Surprisingly, GS10 associates more strongly with zwitterionic and anionic phospholipid bilayer model membranes than does GS, despite its greater water solubility, and the presence of anionic phospholipids and cholesterol (Chol) modestly reduces the association of both GS10 and GS to these model membranes. The strong partitioning of both peptides into lipid bilayers is driven by a large favorable entropy change opposed by a much smaller unfavorable enthalpy change. However, GS10 is also less potent than GS at inducing inverted cubic phases in phospholipid bilayer model membranes and at inhibiting the growth of the cell wall-less bacterium Acholeplasma laidlawii B. These results are discussed in terms of the comparative antibiotic and hemolytic activities of these peptides

    An empirical approach towards the efficient and optimal production of influenza-neutralizing ovine polyclonal antibodies demonstrates that the novel adjuvant CoVaccine HT(TM) is functionally superior to Freund's adjuvant

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    Passive immunotherapies utilising polyclonal antibodies could have a valuable role in preventing and treating infectious diseases such as influenza, particularly in pandemic situations but also in immunocompromised populations such as the elderly, the chronically immunosuppressed, pregnant women, infants and those with chronic diseases. The aim of this study was to optimise current methods used to generate ovine polyclonal antibodies. Polyclonal antibodies to baculovirus-expressed recombinant influenza haemagglutinin from A/Puerto Rico/8/1934 H1N1 (PR8) were elicited in sheep using various immunisation regimens designed to investigate the priming immunisation route, adjuvant formulation, sheep age, and antigen dose, and to empirically ascertain which combination maximised antibody output. The novel adjuvant CoVaccine HT™ was compared to Freund’s adjuvant which is currently the adjuvant of choice for commercial production of ovine polyclonal Fab therapies. CoVaccine HT™ induced significantly higher titres of functional ovine anti-haemagglutinin IgG than Freund’s adjuvant but with fewer side effects, including reduced site reactions. Polyclonal hyperimmune sheep sera effectively neutralised influenza virus in vitro and, when given before or after influenza virus challenge, prevented the death of infected mice. Neither the age of the sheep nor the route of antigen administration appeared to influence antibody titre. Moreover, reducing the administrated dose of haemagglutinin antigen minimally affected antibody titre. Together, these results suggest a cost effective way of producing high and sustained yields of functional ovine polyclonal antibodies specifically for the prevention and treatment of globally significant diseases.Natalie E. Stevens, Cara K. Fraser, Mohammed Alsharifi, Michael P. Brown, Kerrilyn R. Diener, John D. Haybal
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