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Search Results: 1 - 10 of 2943 matches for " Jessica Ahern "
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Oxidative Stress Decreases Functional Airway Mannose Binding Lectin in COPD
Hai B. Tran, Jessica Ahern, Greg Hodge, Phillip Holt, Melinda M. Dean, Paul N. Reynolds, Sandra Hodge
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0098571
Abstract: We have previously established that a defect in the ability of alveolar macrophages (AM) to phagocytose apoptotic cells (efferocytosis) and pathogens is a potential therapeutic target in COPD. We further showed that levels of mannose binding lectin (MBL; required for effective macrophage phagocytic function) were reduced in the airways but not circulation of COPD patients. We hypothesized that increased oxidative stress in the airway could be a cause for such disturbances. We therefore studied the effects of oxidation on the structure of the MBL molecule and its functional interactions with macrophages. Oligomeric structure of plasma derived MBL (pdMBL) before and after oxidation (oxMBL) with 2,2′-azobis(2-methylpropionamidine)dihyd?rochroride(AAPH) was investigated by blue native PAGE. Macrophage function in the presence of pd/oxMBL was assessed by measuring efferocytosis, phagocytosis of non-typeable Haemophilus influenzae (NTHi) and expression of macrophage scavenger receptors. Oxidation disrupted higher order MBL oligomers. This was associated with changed macrophage function evident by a significantly reduced capacity to phagocytose apoptotic cells and NTHi in the presence of oxMBL vs pdMBL (eg, NTHi by 55.9 and 27.0% respectively). Interestingly, oxidation of MBL significantly reduced macrophage phagocytic ability to below control levels. Flow cytometry and immunofluorescence revealed a significant increase in expression of macrophage scavenger receptor (SRA1) in the presence of pdMBL that was abrogated in the presence of oxMBL. We show the pulmonary macrophage dysfunction in COPD may at least partially result from an oxidative stress-induced effect on MBL, and identify a further potential therapeutic strategy for this debilitating disease.
La Relación y con udio de Hernán Gallegos: glosa, guía y memoria de Nuevo México 1581-1582
Maureen Ahern
Lexis , 2001,
Abstract: No contiene resúmen
Sarah Ahern
Literacy and Numeracy Studies , 2011,
Abstract: EDITED BY ANNE BURNS AND HELEN DE SILVA JOYCE National Centre for English Language Teaching and Research, Macquarie University, Sydney NSW 2005, 77pp, ISBN 1 74138 103 7 This is the most recent book in a series that deals with teaching and learning in the classroom. The specific focus of this book is the explicit support of reading and writing in adult ESL teaching, investigated through classroom projects within the framework of an action research approach. It consists of three sections: the first outlines the theoretical ideas underpinning the book, the second deals with the nature of action research, and the third and longest section presents the participating teachers’ own accounts of their research projects. It is accompanied by a DVD containing excerpts of their classroom teaching.
Images in Emergency Medicine: Traumatic Pneumocephalus
Ahern, Terence
Western Journal of Emergency Medicine : Integrating Emergency Care with Population Health , 2008,
The FDSN Archive at the IRIS Data Management Center
T. Ahern
Annals of Geophysics , 1994, DOI: 10.4401/ag-4202
Abstract: In August of 1990, the IRIS Data Management Center (IRIS DMC) was designated as the first FDSN Data Center. Since that time the IRIS DMC has also come to be known as the FDSN Archive. As the FDSN Archive, all member networks, through their own local Network Data Centers, routinely send data to the IRIS DMC. At the present time we have received data from seven member networks. These include: CNSN (Canada); CDSN (China); GEOSCOPE (France); Graefenberg (Germany); IRIS GSN (U.S.A.); MEDNET (Italy); POSEIDON (Japan). In addition to acting as the FDSN Archive, the IRIS DMC is responsible for archiving and distributing data from several sources. The Global Seismographie Network (GSN) and the Program for Array Seismic Studies of the Continental Lithosphere (PASSCAL) and the Joint Seismic Program (JSP) are three IRIS programs that presently send data to the IRIS DMS. The DMC also archives data from some regional networks in the United States and in the Former Soviet Union (FSU). The DMC is one component of a larger Data Management System (DMS) consisting of several components including two Data Collection Centers (DCCs), one Data Management Center (DMQ, a DMC Host at the University of Washington, a Wave form Quality Center (WQC), and the Moscow Data Analysis Center (MDC) in Russia.
Defective Lung Macrophage Function in Lung Cancer±Chronic Obstructive Pulmonary Disease (COPD/Emphysema)-Mediated by Cancer Cell Production of PGE2?
Francis C. Dehle, Violet R. Mukaro, Craig Jurisevic, David Moffat, Jessica Ahern, Greg Hodge, Hubertus Jersmann, Paul N. Reynolds, Sandra Hodge
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0061573
Abstract: In chronic obstructive pulmonary disease (COPD/emphysema) we have shown a reduced ability of lung and alveolar (AM) macrophages to phagocytose apoptotic cells (defective ‘efferocytosis’), associated with evidence of secondary cellular necrosis and a resultant inflammatory response in the airway. It is unknown whether this defect is present in cancer (no COPD) and if so, whether this results from soluble mediators produced by cancer cells. We investigated efferocytosis in AM (26 controls, 15 healthy smokers, 37 COPD, 20 COPD+ non small cell lung cancer (NSCLC) and 8 patients with NSCLC without COPD) and tumor and tumor-free lung tissue macrophages (21 NSCLC with/13 without COPD). To investigate the effects of soluble mediators produced by lung cancer cells we then treated AM or U937 macrophages with cancer cell line supernatant and assessed their efferocytosis ability. We qualitatively identified Arachidonic Acid (AA) metabolites in cancer cells by LC-ESI-MSMS, and assessed the effects of COX inhibition (using indomethacin) on efferocytosis. Decreased efferocytosis was noted in all cancer/COPD groups in all compartments. Conditioned media from cancer cell cultures decreased the efferocytosis ability of both AM and U937 macrophages with the most pronounced effects occurring with supernatant from SCLC (an aggressive lung cancer type). AA metabolites identified in cancer cells included PGE2. The inhibitory effect of PGE2 on efferocytosis, and the involvement of the COX-2 pathway were shown. Efferocytosis is decreased in COPD/emphysema and lung cancer; the latter at least partially a result of inhibition by soluble mediators produced by cancer cells that include PGE2.
Space Technology for Decarbonising City Precincts  [PDF]
Jessica Bunning
Journal of Geographic Information System (JGIS) , 2013, DOI: 10.4236/jgis.2013.55042
Abstract: Space technology is a powerful tool for climate research. Satellite data improve knowledge of the human impact on the Planet’s physical geography. Similarly, remote sensing technology enhances understanding of the human impact on rising global carbon emissions. However, so far satellites have been principally limited to measuring the carbon emissions of cities from space. Standing alone, satellite technology is incapable of advancing the goal of decarbonisation. This will be achieved only if cities create local methodologies that significantly enhance the carbon reduction process. There exists enormous potential to bridge remote sensing for earth observation and global environmental change with local action towards decarbonised urban renewal and redevelopment. Satellite remote sensing has the ability to demonstrate if local remedial strategies are succeeding, and assist with planning, developing, and monitoring low and zero carbon infrastructure systems. Satellite-derived data can facilitate informed discussion and decision-making between community stakeholders to deliver low carbon outcomes at the precinct scale. Satellite-based systems can be integrated within the urban fabric to assist climate change mitigation. This paper is based on current work implemented jointly with municipalities to ascertain where within city precincts carbon emissions originate and how they can ultimately be reduced. It presents space technology as an instrumental tool for understanding the carbon impact of citiesin terms of the carbon intensive patterns and processes that shape human society, as well as having great potential for providing end-user products to communities to enhance the process of decarbonising city precincts.
An Experimental Study of Microbial Fuel Cells for Electricity Generating: Performance Characterization and Capacity Improvement  [PDF]
Jessica Li
Journal of Sustainable Bioenergy Systems (JSBS) , 2013, DOI: 10.4236/jsbs.2013.33024

This paper studies the electricity generating capacity of microbial fuel cells (MFCs). Unlike most of MFC research, which targets the long term goals of renewable energy production and wastewater treatment, this paper considers a niche application that may be used immediately in practice, namely powering sensors from soils or sediments. There are two major goals in this study. The first goal is to examine the performance characteristics of MFCs in this application. Specifically we investigate the relationship between the percentage of organic matter in a sample and the electrical capacity of MFCs fueled by that sample. We observe that higher percentage of organic matter in a sample results in higher electricity production of MFCs powered by that sample. We measure the thermal limits that dictate the temperature range in which MFCs can function, and confirm that the upper thermal limit is 40℃. The new observation is that the lower thermal limit is -5℃, which is lower than 0℃ reported in the literature. This difference is important for powering environmental sensors. We observe that the electricity production of MFCs decreases almost linearly over a period of 10 days. The second goal is to determine the conditions under which MFCs work most efficiently to generate electricity. We compare the capacity under a variety of conditions of sample types (benthic mud, top soil, and marsh samples), temperatures (0℃, 40℃, and room temperature), and sample sizes (measuring 3.5 cm × 3.5 cm × 4.6 cm, 10.2 cm × 10.2 cm × 13.4 cm, and 2.7 cm × 2.7 cm × 3.8 cm), and find that the electricity capacity is greatest at 0℃, powered by benthic mud sample with the largest chamber size. What seems surprising is that 0℃ outperforms both room temperature and benthic mud sample outperforms marsh sample, which appears to be richer in organic matter. In addition, we notice that although the largest chamber size produces the greatest capacity, it suffers

Control Schemes to Reduce Risk of Extinction in the Lotka-Volterra Predator-Prey Model  [PDF]
Jessica Li
Journal of Applied Mathematics and Physics (JAMP) , 2014, DOI: 10.4236/jamp.2014.27071

The Lotka-Volterra predator-prey model is widely used in many disciplines such as ecology and economics. The model consists of a pair of first-order nonlinear differential equations. In this paper, we first analyze the dynamics, equilibria and steady state oscillation contours of the differential equations and study in particular a well-known problem of a high risk that the prey and/or predator may end up with extinction. We then introduce exogenous control to reduce the risk of extinction. We propose two control schemes. The first scheme, referred as convergence guaranteed scheme, achieves very fine granular control of the prey and predator populations, in terms of the final state and convergence dynamics, at the cost of sophisticated implementation. The second scheme, referred as on-off scheme, is very easy to implement and drive the populations to steady state oscillation that is far from the risk of extinction. Finally we investigate the robustness of these two schemes against parameter mismatch and observe that the on-off scheme is much more robust. Hence, we conclude that while the convergence guaranteed scheme achieves theoretically optimal performance, the on-off scheme is more attractive for practical applications.

TRPA1 Is a Polyunsaturated Fatty Acid Sensor in Mammals
Arianne L. Motter, Gerard P. Ahern
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0038439
Abstract: Fatty acids can act as important signaling molecules regulating diverse physiological processes. Our understanding, however, of fatty acid signaling mechanisms and receptor targets remains incomplete. Here we show that Transient Receptor Potential Ankyrin 1 (TRPA1), a cation channel expressed in sensory neurons and gut tissues, functions as a sensor of polyunsaturated fatty acids (PUFAs) in vitro and in vivo. PUFAs, containing at least 18 carbon atoms and three unsaturated bonds, activate TRPA1 to excite primary sensory neurons and enteroendocrine cells. Moreover, behavioral aversion to PUFAs is absent in TRPA1-null mice. Further, sustained or repeated agonism with PUFAs leads to TRPA1 desensitization. PUFAs activate TRPA1 non-covalently and independently of known ligand binding domains located in the N-terminus and 5th transmembrane region. PUFA sensitivity is restricted to mammalian (rodent and human) TRPA1 channels, as the drosophila and zebrafish TRPA1 orthologs do not respond to DHA. We propose that PUFA-sensing by mammalian TRPA1 may regulate pain and gastrointestinal functions.
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