1,581 research outputs found
Meaningful Chemical Measurements in the Marine Environment - Transition Metals
The following comments present a critical, but not negative, point of view that seeks identification of improved approaches to marine pollution effects studies. The current literature has many examples of the disquiet that the authors experience in reviewing or participating in recent studies. As pointed out by Dayton (1982), in reviewing the proceedings of a symposium: The Shore Environment, Environmental protection programs are increasingly criticized by ecologists, regulatory and management agencies, and private business as being of questionable quality and value. Because regulatory agencies and many ecologists are uncomfortable with the highly probabilistic nature of ecology, there is a tendency, often a legal necessity, for impact studies to be very detailed and specific and to collect reams of data that have no underlying logic and defy generalization or test. This prevents the growth of coastal ecology as a science. It seems interesting and paradoxicaI that the collection of a large amount of data prevents the growth of a particular science, but it seems to be true.https://scholarworks.wm.edu/vimsbooks/1099/thumbnail.jp
Long-term results of cyclosporine-steroid therapy in 131 non-matched cadaveric renal transplants.
One-hundred-and-twenty-eight recipients of 131 consecutive, non-matched cadaver renal allografts were treated with cyclosporine and steroids. They have been followed for 4 to 6 yr. Cumulative patient survival at 1-yr was 92.2% and at 6yr it is 77.8%. Cumulative graft survival at 1-yr was 79.4% and at 6 yr it is 50.0%. After the high-risk 1st yr, the rate of graft loss was even and similar to that reported after the 1st yr for grafts treated with azathioprine and steroids. This indicates that cyclosporine nephrotoxicity has not had an obvious adverse effect on the survival of chronically functioning grafts. The results were better with primary grafting versus retransplantation, but were not significantly influenced by age, diabetes mellitus, or a delayed switch in patients from cyclosporine to azathioprine. We have concluded that cyclosporine-steroid therapy is safe and effective for long-term use after cadaveric renal transplantation
The Chlamydia trachomatis Type III Secretion Chaperone Slc1 Engages Multiple Early Effectors, Including TepP, a Tyrosine-phosphorylated Protein Required for the Recruitment of CrkI-II to Nascent Inclusions and Innate Immune Signaling
Chlamydia trachomatis, the causative agent of trachoma and sexually transmitted infections, employs a type III secretion (T3S) system to deliver effector proteins into host epithelial cells to establish a replicative vacuole. Aside from the phosphoprotein TARP, a Chlamydia effector that promotes actin re-arrangements, very few factors mediating bacterial entry and early inclusion establishment have been characterized. Like many T3S effectors, TARP requires a chaperone (Slc1) for efficient translocation into host cells. In this study, we defined proteins that associate with Slc1 in invasive C. trachomatis elementary bodies (EB) by immunoprecipitation coupled with mass spectrometry. We identified Ct875, a new Slc1 client protein and T3S effector, which we renamed TepP (Translocated early phosphoprotein). We provide evidence that T3S effectors form large molecular weight complexes with Scl1 in vitro and that Slc1 enhances their T3S-dependent secretion in a heterologous Yersinia T3S system. We demonstrate that TepP is translocated early during bacterial entry into epithelial cells and is phosphorylated at tyrosine residues by host kinases. However, TepP phosphorylation occurs later than TARP, which together with the finding that Slc1 preferentially engages TARP in EBs leads us to postulate that these effectors are translocated into the host cell at different stages during C.trachomatis invasion. TepP co-immunoprecipitated with the scaffolding proteins CrkI-II during infection and Crk was recruited to EBs at entry sites where it remained associated with nascent inclusions. Importantly, C. trachomatis mutants lacking TepP failed to recruit CrkI-II to inclusions, providing genetic confirmation of a direct role for this effector in the recruitment of a host factor. Finally, endocervical epithelial cells infected with a tepP mutant showed altered expression of a subset of genes associated with innate immune responses. We propose a model wherein TepP acts downstream of TARP to recruit scaffolding proteins at entry sites to initiate and amplify signaling cascades important for the regulation of innate immune responses to Chlamydia.Fil: Chen, Yi-Shan. University of Duke; Estados UnidosFil: Bastidas, Robert J.. University of Duke; Estados UnidosFil: Saka, Hector Alex. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Córdoba; Argentina. University of Duke; Estados UnidosFil: Carpenter, Victoria K.. Duke University Medical Center; . University of Duke; Estados UnidosFil: Richards, Kristian L.. Miami University; Estados UnidosFil: Plano, Gregory V.. Miami University; Estados UnidosFil: Valdivia, Raphael H.. University of Duke; Estados Unido
A Review of Electronic Devices to Assess Inhaler Technique
Multiple electronic devices exist that provide feedback on the accuracy of patient inhaler technique. Our purpose is to describe the inhaler technique feedback provided by these devices, including specific technique steps measured, how feedback is displayed, target of feedback (patient, provider, researcher), and compatibility with inhaler type (metered-dose inhaler [MDI], diskus, etc.)
Comparison of first pass bolus AIFs extracted from sequential 18F-FDG PET and DSC-MRI of mice.
Accurate kinetic modelling of in vivo physiological function using positron emission tomography (PET) requires determination of the tracer time-activity curve in plasma, known as the arterial input function (AIF). The AIF is usually determined by invasive blood sampling methods, which are prohibitive in murine studies due to low total blood volumes. Extracting AIFs from PET images is also challenging due to large partial volume effects (PVE). We hypothesise that in combined PET with magnetic resonance imaging (PET/MR), a co-injected bolus of MR contrast agent and PET ligand can be tracked using fast MR acquisitions. This protocol would allow extraction of a MR AIF from MR contrast agent concentration-time curves, at higher spatial and temporal resolution than an image-derived PET AIF. A conversion factor could then be applied to the MR AIF for use in PET kinetic analysis. This work has compared AIFs obtained from sequential DSC-MRI and PET with separate injections of gadolinium contrast agent and 18F-FDG respectively to ascertain the technique's validity. An automated voxel selection algorithm was employed to improve MR AIF reproducibility. We found that MR and PET AIFs displayed similar character in the first pass, confirmed by gamma variate fits (p<0.02). MR AIFs displayed reduced PVE compared to PET AIFs, indicating their potential use in PET/MR studies.This work was funded by an MRC studentship and travel to PSMR 2013 was funded by the EU COST action for PET/MR.This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.nima.2013.08.07
Water in a Changing World
Life on earth depends on the continuous flow of materials through the air, water, soil, and food webs of the biosphere. The movement of water through the hydrological cycle comprises the largest of these flows, delivering an estimated I 10,000 cubic kilometers (km^\u3e of water to the land each year as snow and rainfall. Solar energy drives the hydrological cycle, vaporizing water from the surface of oceans, lakes, and rivers as well as from soils and plants (evapotranspiration). Water vapor rises into the atmosphere where it cools, condenses, and eventually rains down anew. This renewable freshwater supply sustains life on the land, in estuaries, and in the freshwater ecosystems of the earth
A quantum sensing metrology for magnetic memories
Magnetic random access memory (MRAM) is a leading emergent memory technology
that is poised to replace current non-volatile memory technologies such as
eFlash. However, the scaling of MRAM technologies is heavily affected by
device-to-device variability rooted in the stochastic nature of the MRAM
writing process into nanoscale magnetic layers. Here, we introduce a
non-contact metrology technique deploying Scanning NV Magnetometry (SNVM) to
investigate MRAM performance at the individual bit level. We demonstrate
magnetic reversal characterization in individual, < 60 nm sized bits, to
extract key magnetic properties, thermal stability, and switching statistics,
and thereby gauge bit-to-bit uniformity. We showcase the performance of our
method by benchmarking two distinct bit etching processes immediately after
pattern formation. Unlike previous methods, our approach unveils marked
differences in switching behaviour of fully contacted MRAM devices stemming
from these processes. Our findings highlight the potential of nanoscale quantum
sensing of MRAM devices for early-stage screening in the processing line,
paving the way for future incorporation of this nanoscale characterization tool
in the semiconductor industry
Spacecraft Standardization Through Nuclear Power
A conceptual design study showed that standardized, shuttle-launched spacecraft serving many space missions and a wide variety of orbital conditions could be designed around the use of nuclear electric power systems. One spacecraft design was based on the use of from one to three radioisotope thermoelectric generators (RTG) to provide up to 450 watts of electrical power. A second design based on a Brayton cycle alternator fueled by up to three of the same RTG heat sources meets power requirements from 5000 to 2000 watts. Both spacecraft provide adequate weight, volume, and mounting surfaces for most of the payloads anticipated in the 1980 decade. A key to the broad applicability of the designs is the use of waste heat from the radioisotope heat sources to provide a benign environment for all internal equipment in all orbits with minimal spacecraft changes. Economic analysis indicated that the development cost of such spacecraft would be amortized over very few missions, with significant savings thereafter. There are three copies in the file
Pasts and pagan practices: moving beyond Stonehenge
Theorizing the past is not restricted to archaeology and interpretations of 'past' both influence and are themselves constituted within politicized understandings of self, community and in certain instances, spirituality. 'The past in the imagination of the present' is appropriated, variously, to give meaning to the present or to justify actions and interpret experiences. Summer solstice at Stonehenge, with an estimated 21,000 celebrants in 2005, is only the most publicized appropriation (by pagans and other adherents of alternative spirituality and partying) of a 'sacred site'; and conflicts and negotiations occurring throughout Britain are represented in popular and academic presentations of this 'icon of Britishness'. This paper presents work from the Sacred Sites, Contested Rites/Rights Project (http://www.sacredsites.org.uk) project, a collaboration of archaeology and anthropology informed by pagan and alternative approaches and standpoints investigating and theorizing discourse and practice of heritage management and pagan site users. Whether in negotiations around the Stonehenge solstice access or in dealing with numerous other sites, boundaries between groups or discourses are not clearly drawn - discursive communities merge and re-emerge. But clearly 'past' and 'site' are increasingly important within today's Britain, even as television archaeology increases its following, and pagan numbers continue to grow.</p
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