Search Results - (Author, Cooperation:L. Courtney)

2012-03-01

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Animals ; Chromosomes, Human, Y/*genetics ; Conserved Sequence/*genetics ; Crossing Over, Genetic/genetics ; *Evolution, Molecular ; Gene Amplification/genetics ; *Gene Deletion ; Humans ; In Situ Hybridization, Fluorescence ; Macaca mulatta/*genetics ; Male ; Models, Genetic ; Molecular Sequence Data ; Pan troglodytes/genetics ; Radiation Hybrid Mapping ; Selection, Genetic/genetics ; Time Factors ; Y Chromosome/*genetics

1600-065X

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

The origin of adaptive immunity in the vertebrates can be traced to the appearance of the ancestral RAG genes in the ancestral jawed vertebrate; however, the innate immune system is more ancient. A central subsystem within innate immunity is the complement system, which has been identified throughout and seems to be restricted to the deuterostomes. The evolutionary history of complement can be traced from the sea urchins (members of the echinoderm phylum), which have a simplified system homologous to the alternative pathway, through the agnathans (hagfish and lamprey) and the elasmobranchs (sharks and rays) to the teleosts (bony fish) and tetrapods, with increases in the numbers of complement components and duplications in complement pathways. Increasing complexity in the complement system parallels increasing complexity in the deuterostome animals. This review focuses on the simplest of the complement systems that is present in the sea urchin. Two components have been identified that show significant homology to vertebrate C3 and factor B (Bf), called SpC3 and SpBf, respectively. Sequence analysis from both molecules reveals their ancestral characteristics. Immune challenge of sea urchins indicates that SpC3 is inducible and is present in coelomic fluid (the body fluids) in relatively high concentrations, while SpBf expression is constitutive and is present in much lower concentrations. Opsonization of foreign cells and particles followed by augmented uptake by phagocytic coelomocytes appears to be a central function for this simpler complement system and important for host defense in the sea urchin. These activities are similar to some of the functions of the homologous proteins in the vertebrate complement system. The selective advantage for the ancestral deuterostome may have been the amplification feedback loop that is still of central importance in the alternative pathway of complement in higher vertebrates. Feedback loop functions would quickly coat pathogens with complement leading to phagocytosis and removal of foreign cells, a system that would be significantly more effective than an opsonin that binds upon contact as a result of simple diffusion. An understanding of the immune response of the sea urchin, an animal that is a good estimator of what the ancestral deuterostome immune system was like, will aid us in understanding how adaptive immunity might have been selected for during the early evolution of the vertebrates and how it might have been integrated into the pre-existing innate immune system that was already in place in those animals.The authors are grateful to Drs Sham Nair and Paul Gross for their critique of the manuscript and helpful suggestions. This work was supported by the National Science Foundation (MCB 9603086).

Electronic Resource

1749-6632

Blackwell Publishing Journal Backfiles 1879-2005

Natural Sciences in General

Electronic Resource

1432-1211

Complement C3 Coelomocyte Evolution Innate Lipopolysaccharide

Springer Online Journal Archives 1860-2000

Biology

Medicine

Abstract. The lower deuterostomes, including the echinoderms, possess an innate immune system that includes a subsystem with similarities to the vertebrate complement system. A homologue of the central component of this system, C3, has recently been identified in the purple sea urchin, Strongylocentrotus purpuratus, and is called SpC3. We determined previously that coelomocytes specifically express the SpC3 gene (Sp064); however, the sea urchin has at least four different types of coelomocytes: amoeboid phagocytes, red spherule cells, colorless spherule cells, and vibratile cells. To determine which of these subpopulations expresses Sp064 and produces SpC3, coelomocytes were separated by discontinuous gradient density centrifugation. Relatively homogenous fractions were obtained consisting of the four major cell types in addition to two types of amoeboid phagocytes with different densities and distinct morphologies. Analysis of proteins from separated cell subpopulations by Western blot and analysis of gene expression by RT-PCR revealed that phagocytes express the gene and contain the protein. Immunolocalization showed that SpC3+ phagocytes are present as subsets of both the low- and high-density subpopulations of phagocytes; however, the subcellular localization of SpC3 is different in these two subpopulations.

Electronic Resource

1432-1211

Innate immunity Sea urchin Complement C3 SpC3 Coelomocyte

Springer Online Journal Archives 1860-2000

Biology

Medicine

Abstract. The homologue of the vertebrate complement component C3 that is expressed in the coelomocytes of the purple sea urchin, Strongylocentrotus purpuratus, designated SpC3, was investigated for changes in response to immune challenge or injury. Immunoquiescent animals were used in this study because they have reduced or no detectible SpC3 in their coelomocytes or coelomic fluid (CF). Animals were injected with lipopolysaccharide (LPS) or sterile sea water (SSW, injury control). Changes in the amounts of SpC3 in coelomic fluid and in coelomocytes were then followed over time by Western blots and ELISA. Changes in mRNA from the SpC3 gene (Sp064) were also followed by RT-PCR. Although all animals responded to injury with increased levels of SpC3 in the coelomic fluid, those challenged with LPS had greater amounts of SpC3 in both CF and coelomocytes than those receiving SSW. In most of the animals receiving LPS, initial increases in SpC3 were observed within 1 h post-injection, while the earliest response in the animals receiving SSW was 6 h. The appearance of SpC3 in the coelomocytes was delayed compared to its appearance in CF, and was first detected several days after challenge. Changes in mRNA from the Sp064 gene paralleled the appearance of SpC3 in the coelomic fluid. Increases in the number of coelomocytes per milliliter of CF and in the percentage of coelomocytes that were SpC3+ also occurred after challenge with LPS or in response to injury, with a slightly greater increase in response to LPS. Although the changes in SpC3 were not as great as those identified previously for human C3 expressed in macrophages, the kinetics of the response are similar to that of acute-phase reactants in mammals.

Electronic Resource

2022-05-11

Ranked choice voting (RCV) has become increasing popular in the United States as more cities and states begin allowing voters to rank candidates in order of preference. This change in election system has been linked to increased campaign civility and mobilization, but with little evidence suggesting these benefits lead to increased voter turnout in the general population. This study argues that RCV elections may not increase overall voting but will increase youth voting. Considering young Americans, who have become increasingly pessimistic towards politics and are also heavily reliant on mobilization for participation, this study argues that increased campaign civility and mobilization may work to offset the negative feelings and lack of political engagement that plague young Americans. Using a matched study of individual level voter turnout for seven RCV and fourteen non-RCV local elections from 2013 and 2014, we find that there is no statistical difference in voting rates between RCV and plurality cities for the general public. Yet, in line with our hypotheses, younger voters are more likely to vote in RCV cities. Further, we find that increased contact in RCV elections accounts for a larger portion of the increased voter turnout compared to perceptions of campaign civility. Findings suggest RCV acts as a positive mobilizing force for youth voting through increasing campaign contact.

Politikwissenschaft ; Political science ; campaign civility; mobilization; ranked choice voting; voter turnout; youth voting ; politische Willensbildung, politische Soziologie, politische Kultur ; Political Process, Elections, Political Sociology, Political Culture ; Wahlsystem ; USA ; junger Erwachsener ; Wahlverhalten ; Wahlkampf ; politische Strategie ; electoral system ; United States of America ; young adult ; voting behavior ; election campaign ; political strategy

Zeitschriftenartikel, journal article

article

2022

Chancengleichheit ; Soziale Ungleichheit ; Identität ; Frau ; Geschlechterbeziehung ; Gleichberechtigung ; Geschlechterforschung ; Bildungspolitik ; Schulpolitik ; High School ; Geschlecht ; Geschlechtsdifferenzierung ; Rasse ; Geschichte (Histor) ; Diskriminierung ; Gesetzgebung ; Politik ; Politische Beeinflussung ; Politische Entwicklung ; Soziale Gerechtigkeit ; Sozialpolitik ; Transsexualität ; Frauensport ; Schulsport ; Sport ; Sportgeschichte ; Sportsoziologie ; Collegesport ; Mädchen ; USA

Women in sport & physical activity journal, Bd. 30 (2022) H. 2, S. 71-84, 1063-6161

1938-1581

English

article

2005

Bildungsgeschichte ; Hochschulgeschichte ; Geschichte (Histor) ; Aufhebung ; Bürgerrechtsbewegung ; Rassentrennung ; Universität ; 20. Jahrhundert ; Baptist ; Schwarzer ; South Carolina ; USA

History of higher education annual, (2005) H. 23, S. 23-48, 0737-2698

English

Literaturangaben S. 43-48

2018-02-20

Wiley-Blackwell

2045-7758

Biology

2018-06-27

American Physical Society (APS)

1098-0121

1095-3795

Physics

Dynamics, dynamical systems, lattice effects

2018-06-13

Institute of Physics (IOP)

1748-9318

1748-9326

Biology

Energy, Environment Protection, Nuclear Power Engineering

2018-08-15

American Chemical Society (ACS)

0006-2960

1520-4995

Biology

Chemistry and Pharmacology

2018-09-13

Nature Publishing Group (NPG)

2041-1723

Biology

Chemistry and Pharmacology

Natural Sciences in General

Physics

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

The quantum trajectory method (QTM) is extended to the dynamics of electronic nonadiabiatic collisions. Equations of motion are first derived for the probability density, velocity, and action function for wave packets moving on each of the coupled electronic potential surfaces. These discretized equations are solved in the Lagrangian (moving with the fluid) picture to give the trajectory dynamics of fluid elements evolving on each potential surface. This trajectory method is fully quantum mechanical and does not involve "trajectory surface hopping." The method is applied to nonadiabiatic collision models involving two coupled electronic states. The quantum trajectory results are in excellent agreement with solutions computed (using space-fixed grid methods) directly from the time-dependent Schrödinger equation. © 2001 American Institute of Physics.

Electronic Resource

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

Complete sets of quadratic and cubic force constants calculated for four isotopomers of dioxirane (CH2OO) are used to estimate vibration-rotation interaction contributions to observed values of rotational constants (B″), thereby yielding empirical estimates of the corresponding equilibrium values (Be). At the highest levels of theory, least-squares refinements of atomic coordinates to both the empirical Be values and the associated isotope shifts yield consistent sets of structural parameters. Recommended values are re(CO)=1.3846±0.0005 Å; re(OO)=1.5133±0.0005 Å; re(CH)=1.0853±0.0015 Å and θe(HCH)=117.03±0.20°. Semidiagonal quartic force constants (in the normal coordinate representation) also calculated for CH2OO are used to estimate anharmonic contributions to the fundamental vibrational frequencies. Arguments based on the latter set of results support those made in a previous theoretical study and clearly show that two infrared features assigned to dioxirane in a matrix-isolation experiment must be due to a different carrier. © 1998 American Institute of Physics.

Electronic Resource

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

The quantum trajectory method (QTM) is applied to nonadiabatic electronic transitions. Equations of motion in a Lagrangian framework are derived for the probability density, velocity, position, and action functions for a discretized wave packet moving along coupled potential energy surfaces. In solving these equations of motion, we obtain agreement with exact quantum results computed by solving the time-dependent Schrödinger equation on a space-fixed grid. On each of the coupled potential energy surfaces, the dynamics of the trajectories is fully quantum mechanical, i.e., there are no "surface–hopping transitions." We present a detailed analysis of the QTM results including density changes, complex oscillations of the wave functions, phase space analysis, and a detailed discussion of the forces that contribute to the evolution the trajectories. © 2002 American Institute of Physics.

Electronic Resource

1365-2761

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Medicine

Electronic Resource

0010-7565

General, Interdisciplinary

0010-7565

General, Interdisciplinary

0010-7565

General, Interdisciplinary