8,490 research outputs found
CONSUMERS' VALUATION OF INSECTICIDE USE RESTRICTIONS: AN APPLICATION TO APPLES
Economic assessments of pesticide regulations typically focus on producer impacts and generally ignore possible changes in product demand. These changes may be nonnegligible if real and/or perceived product attributes change. We measure consumersÂ’' willingness to pay (WTP) for the elimination of one insecticide and also a whole group of insecticides in apple production using a multiple-round Vickrey auction. The data are analyzed using nonparametric statistical tests and a double-hurdle model. Our findings show that consumer perceptions of product attributes change if pesticides are removed from production, and this is reflected in WTP changes. WTP is shown to be income elastic.Consumer/Household Economics, Crop Production/Industries,
Archaeological Testing of Proposed Sewer Line Location at Mission San Jose
In April 1984 archaeologists from the Center for Archaeological Research, The University of Texas at San Antonio, excavated a backhoe trench outside the west wall of Mission San José. The purpose of the investigation was to determine if a proposed sewer line for the San Antonio 201 Wastewater Facilities Improvements Project would affect any major historic or prehistoric resources. A stone-lined well was found that was constructed sometime after the secularization of the mission in 1893 and continued in use, first as a well and later as a privy pit, until ca. 1940. Because of the likelihood of stratified deposits of 19th century artifacts within the well fill, the site is recommended for archaeological excavation
Destabilization of α-helical structure in solution improves bactericidal activity of antimicrobial peptides: Opposing effects on bacterial and viral targets
We have previously examined the mechanism of antimicrobial peptides on the outer membrane of vaccinia virus. Here we show that the formulation of peptides LL37 and magainin-2B amide in polysorbate 20 (Tween-20™) results in greater reductions in virus titre than formulation without detergent, and the effect is replicated by substitution of polysorbate 20 with high ionic strength buffer. In contrast, formulation with polysorbate 20 or high ionic strength buffer has the opposite effect on bactericidal activity of both peptides, resulting in lesser reductions in titre for both gram-positive and gram-negative bacteria. Circular dichroism spectroscopy shows that the differential action of polysorbate 20 and salt on the virucidal and bactericidal activities correlates with the α-helical content of peptide secondary structure in solution, suggesting that the virucidal and bactericidal activities are mediated through distinct mechanisms. The correlation of a defined structural feature with differential activity against a host-derived viral membrane and the membranes of both gram-positive and gram-negative bacteria suggests that overall helical content in solution under physiological conditions is an important feature for consideration in the design and development of candidate peptide-based antimicrobial compounds
Reduced Fas ligand-expressing splenic CD5+ B lymphocytes in severe collagen-induced arthritis
Abstract
Introduction
The objective was to study immune regulation in a mouse model of rheumatoid arthritis that exhibits considerable heterogeneity of disease activity.
Methods
T-cell receptor transgenic mice, in which nearly all CD4+ T cells recognize a single peptide of type II collagen, were immunized with collagen and observed for development of arthritis for 4 weeks. At 28 days post-immunization, splenocytes were analyzed by flow cytometry and in vitro assays for markers of immune activation and regulation.
Results
Disease severities ranging from 0 to 12 (on a 12-point scale) were observed. Among splenic lymphocyte populations, only the CD5+ B-cell subset displayed a decrease in relative numbers as arthritis severity increased. Splenic CD5+ B cells expressed higher levels of Fas ligand (FasL) than did CD4+ T cells or CD5- B cells in all mice, and antigen-dependent T-cell death correlated with higher levels of CD5+ B cells in cocultures. Ratios of interleukin (IL)-17 to interferon-gamma production were higher in antigen-driven cultures of splenocytes from severely arthritic mice compared to mildly or nonarthritic mice. A correlation was established between the reduced production of IL-17 in antigen-driven T-cell/B-cell cocultures and FasL, but not IL-10. Confirmation of the direct killing effect of B cells on T cells was demonstrated using an antigen-specific T hybridoma cell line.
Conclusions
Reduced numbers of splenic FasL+ CD5+ B cells correlated with increasing arthritis severity and decreased T-cell death in a T-cell receptor transgenic mouse model of collagen-induced arthritis. These 'killer' B cells may provide a novel mechanism for inducing T-cell death as a treatment for arthritis.http://deepblue.lib.umich.edu/bitstream/2027.42/112538/1/13075_2009_Article_2632.pd
Astronomical CCD Imaging at UMR: An Interim Report
Progress towards the modernization and update of the UMR observatory through the implementation of astronomical CCD technology is detailed. Preliminary image data is presented, specifically: globular cluster M13 and the lunar surface. An evaluation of the Santa Barbara Instrument Group’s (SBIG) ST-6 CCD camera is presented; bias frames, dark frames, and flat-fields are all examined. A custom optical assembly for instrument focusing and housing BVRI photometry and RGB colorimetry filters is described. The ST60PS data acquisition program, provided by SBIG, is reviewed. Additional work towards the development of a custom image processing utility program is mentioned. Finally, optical telescope collimation and polar alignment issues are discussed
Avirulent Uracil Auxotrophs Based on Disruption of Orotidine-5′-Monophosphate Decarboxylase Elicit Protective Immunity to Toxoplasma gondii
The orotidine-5\u27-monophosphate decarboxylase (OMPDC) gene, encoding the final enzyme of the de novo pyrimidine biosynthesis pathway, was deleted using Toxoplasma gondii KU80 knockouts to develop an avirulent nonreverting pyrimidine auxotroph strain. Additionally, to functionally address the role of the pyrimidine salvage pathway, the uridine phosphorylase (UP) salvage activity was knocked out and a double knockout of UP and OMPDC was also constructed. The nonreverting DeltaOMPDC, DeltaUP, and DeltaOMPDC DeltaUP knockout strains were evaluated for pyrimidine auxotrophy, for attenuation of virulence, and for their ability to elicit potent immunity to reinfection. The DeltaUP knockout strain was replication competent and virulent. In contrast, the DeltaOMPDC and DeltaOMPDC DeltaUP strains were uracil auxotrophs that rapidly lost their viability during pyrimidine starvation. Replication of the DeltaOMPDC strain but not the DeltaOMPDC DeltaUP strain was also partially rescued in vitro with uridine or cytidine supplementation. Compared to their hypervirulent parental type I strain, the DeltaOMPDC and DeltaOMPDC DeltaUP knockout strains exhibited extreme attenuation in murine virulence (approximately 8 logs). Genetic complementation of the DeltaOMPDC strain using a functional OMPDC allele restored normal replication and type I parental strain virulence phenotypes. A single immunization of mice with either the live critically attenuated DeltaOMPDC strain or the DeltaOMPDC DeltaUP knockout strain effectively induced potent protective immunity to lethal challenge infection. The avirulent nonreverting DeltaOMPDC and DeltaOMPDC DeltaUP strains provide new tools for the dissection of the host response to infection and are promising candidates for safe and effective Th1 vaccine platforms that can be easily genetically engineered
Enhancing Nonprofit Governance through Better Information Flow to Directors
To counteract the ability of a nonprofit’s chief executive officer to control information reaching the board of directors, we recommend that a nonprofit board consider requiring leaders of the organization’s various functions to provide operational reports directly to the board on at least an annual basis. Additionally, we recommend that a board discuss these reports directly with management members, preferably without the participation of the CEO. Implementing such a protocol should strengthen the board’s ability to make decisions based on information from sources in addition to that of the CEO, improve the directors’ ability to independently evaluate members of the management team, and increase the directors’ understanding of the nonprofit’s activities and performance
Building the Brazilian Academic Genealogy Tree
Along the history, many researchers provided remarkable contributions to
science, not only advancing knowledge but also in terms of mentoring new
scientists. Currently, identifying and studying the formation of researchers
over the years is a challenging task as current repositories of theses and
dissertations are cataloged in a decentralized way through many local digital
libraries. Following our previous work in which we created and analyzed a large
collection of genealogy trees extracted from NDLTD, in this paper we focus our
attention on building such trees for the Brazilian research community. For
this, we use data from the Lattes Platform, an internationally renowned
initiative from CNPq, the Brazilian National Council for Scientific and
Technological Development, for managing information about individual
researchers and research groups in Brazil
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