67 research outputs found

    Attenuation of lung graft reperfusion injury by a nitric oxide donor

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    AbstractObjective: One of the primary features of ischemia-reperfusion injury is reduced production of protective autocoids, such as nitric oxide, by dysfunctional endothelium. Administration of a nitric oxide donor during reperfusion of lung grafts may therefore be beneficial through modulation of vascular tone and leukocyte and platelet function. Methods: Rat lung grafts were flushed with University of Wisconsin solution and reperfused for 1 hour in an ex vivo model incorporating a support animal. Group I grafts (n = 6) were reperfused immediately after explantation, group II (n = 6) and III (n = 5) grafts after 24 hours of storage at 4° C. In group III, glyceryl trinitrate, a nitric oxide donor, was administered during the first 10 minutes of reperfusion at a rate of 200 μg/min. In an additional group (n = 5), 200 μg/min hydralazine was administered instead, to assess the effect of vasodilation alone. Results: Graft function in group II deteriorated compared with that in group I, with significant reduction of graft effluent oxygen tension and blood flow and elevation of pulmonary artery pressure, peak airway pressure, and wet/dry weight ratio. In contrast, in group III, glyceryl trinitrate treatment improved graft function to baseline levels in all these parameters. Administration of hydralazine, meanwhile, produced mixed results with only two out of five grafts functioning at control levels. Conclusions: In this model, administration of glyceryl trinitrate to supplement the nitric oxide pathway in the early phase of reperfusion has a sustained beneficial effect on lung graft function after 24-hour hypothermic storage, probably through mechanisms beyond vasodilation alone. (J Thorac Cardiovasc Surg 1997;113:327-34

    Health care professionals’ experience, understanding and perception of need of advanced cancer patients with cachexia and their families: The benefits of a dedicated clinic.

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    BACKGROUND: Cachexia is defined as the on-going loss of skeletal muscle mass that cannot be fully reversed by conventional nutritional support. It is found in up to 80% of patients with advanced cancer and has profound psycho-social consequences for patients and their families. Previous studies demonstrate that many healthcare professionals receive little formal education in cachexia management leading them to feel that they have limited understanding of the syndrome and cannot intervene effectively. This study aims to examine the value of a dedicated cachexia clinic and its influence on staff understanding and practice. METHODS: An exploratory qualitative study was conducted. The study employed semi-structured interviews with a range of healthcare professionals responsible for designing and delivering cancer care in a large teaching hospital in Australia. This hospital had a dedicated cachexia clinic. RESULTS: In-depth interviews were conducted with 8 healthcare professionals and senior managers. Four themes were identified: formal and informal education; knowledge and understanding; truth telling in cachexia and palliative care; and, a multi-disciplinary approach. Findings show that improved knowledge and understanding across a staff body can lead to enhanced staff confidence and a willingness to address cancer cachexia and its consequences with patients and their families. CONCLUSION: Comparisons with similar previous research demonstrate the advantages of providing a structure for staff to gain knowledge about cachexia and how this can contribute to feelings of improved understanding and confidence necessary to respond to the challenge of cachexia

    Black Hole Complementarity vs. Locality

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    The evaporation of a large mass black hole can be described throughout most of its lifetime by a low-energy effective theory defined on a suitably chosen set of smooth spacelike hypersurfaces. The conventional argument for information loss rests on the assumption that the effective theory is a local quantum field theory. We present evidence that this assumption fails in the context of string theory. The commutator of operators in light-front string theory, corresponding to certain low-energy observers on opposite sides of the event horizon, remains large even when these observers are spacelike separated by a macroscopic distance. This suggests that degrees of freedom inside a black hole should not be viewed as independent from those outside the event horizon. These nonlocal effects are only significant under extreme kinematic circumstances, such as in the high-redshift geometry of a black hole. Commutators of space-like separated operators corresponding to ordinary low-energy observers in Minkowski space are strongly suppressed in string theory.Comment: 32 pages, harvmac, 3 figure

    Residence time distributions in surface transient storage zones in streams : estimation via signal deconvolution

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    Author Posting. © American Geophysical Union, 2011. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Water Resources Research 47 (2011): W05509, doi:10.1029/2010WR009959.Little is known about the impact of surface transient storage (STS) zones on reach-scale transport and the fate of dissolved nutrients in streams. Exchange with these locations may influence the rates of nutrient cycling often observed in whole-stream tracer experiments, particularly because they are sites of organic matter collection and lower flow velocities than those observed in the thalweg. We performed a conservative stream tracer experiment (slug of dissolved NaCl) in the Ipswich River in northeastern Massachusetts and collected solute tracer data both in the thalweg and adjacent STS zones at three locations in a fifth-order reach. Tracer time series observed in STS zones are an aggregate of residence time distributions (RTDs) of the upstream transport to that point (RTDTHAL) and that of the temporary storage within these zones (RTDSTS). Here we demonstrate the separation of these two RTDs to determine the RTDSTS specifically. Total residence times for these individual STS zones range from 4.5 to 7.5 h, suggesting that these zones have the potential to host important biogeochemical transformations in stream systems. All of the RTDSTS show substantial deviations from the ideal prescribed by the two-state (mobile/immobile) mass transfer equations. The deviations indicate a model mismatch and that parameter estimation based on the mass transfer equations will yield misleading values.This research was funded by the National Science Foundation, grants DEB 06-14350 and EAR 07- 49035, and DOE grant DE-FG02-07ER15841

    Representing the function and sensitivity of coastal interfaces in earth system models

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    © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Ward, N. D., Megonigal, J. P., Bond-Lamberty, B., Bailey, V. L., Butman, D., Canuel, E. A., Diefenderfer, H., Ganju, N. K., Goni, M. A., Graham, E. B., Hopkinson, C. S., Khangaonkar, T., Langley, J. A., McDowell, N. G., Myers-Pigg, A. N., Neumann, R. B., Osburn, C. L., Price, R. M., Rowland, J., Sengupta, A., Simard, M., Thornton, P. E., Tzortziou, M., Vargas, R., Weisenhorn, P. B., & Windham-Myers, L. Representing the function and sensitivity of coastal interfaces in earth system models. Nature Communications, 11(1), (2020): 2458, doi:10.1038/s41467-020-16236-2.Between the land and ocean, diverse coastal ecosystems transform, store, and transport material. Across these interfaces, the dynamic exchange of energy and matter is driven by hydrological and hydrodynamic processes such as river and groundwater discharge, tides, waves, and storms. These dynamics regulate ecosystem functions and Earth’s climate, yet global models lack representation of coastal processes and related feedbacks, impeding their predictions of coastal and global responses to change. Here, we assess existing coastal monitoring networks and regional models, existing challenges in these efforts, and recommend a path towards development of global models that more robustly reflect the coastal interface.Funding for this work was provided by Pacific Northwest National Laboratory (PNNL) Laboratory Directed Research & Development (LDRD) as part of the Predicting Ecosystem Resilience through Multiscale Integrative Science (PREMIS) Initiative. PNNL is operated by Battelle for the U.S. Department of Energy under Contract DE-AC05-76RL01830. Additional support to J.P.M. was provided by the NSF-LTREB program (DEB-0950080, DEB-1457100, DEB-1557009), DOE-TES Program (DE-SC0008339), and the Smithsonian Institution. This manuscript was motivated by discussions held by co-authors during a three-day workshop at PNNL in Richland, WA: The System for Terrestrial Aquatic Research (STAR) Workshop: Terrestrial-Aquatic Research in Coastal Systems. The authors thank PNNL artist Nathan Johnson for preparing the figures in this manuscript and Terry Clark, Dr. Charlette Geffen, and Dr. Nancy Hess for their aid in organizing the STAR workshop. The authors thank all workshop participants not listed as authors for their valuable insight: Lihini Aluwihare (contributed to biogeochemistry discussions and development of concept for Fig. 3), Gautam Bisht (contributed to modeling discussion), Emmett Duffy (contributed to observational network discussions), Yilin Fang (contributed to modeling discussion), Jeremy Jones (contributed to biogeochemistry discussions), Roser Matamala (contributed to biogeochemistry discussions), James Morris (contributed to biogeochemistry discussions), Robert Twilley (contributed to biogeochemistry discussions), and Jesse Vance (contributed to observational network discussions). A full report on the workshop discussions can be found at https://www.pnnl.gov/publications/star-workshop-terrestrial-aquatic-research-coastal-systems

    A COL17A1 Splice-Altering Mutation Is Prevalent in Inherited Recurrent Corneal Erosions

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    PurposeCorneal dystrophies are a genetically heterogeneous group of disorders. We previously described a family with an autosomal dominant epithelial recurrent erosion dystrophy (ERED). We aimed to identify the underlying genetic cause of ERED in this family and 3 additional ERED families. We sought to characterize the potential function of the candidate genes using the human and zebrafish cornea.DesignCase series study of 4 white families with a similar ERED. An experimental study was performed on human and zebrafish tissue to examine the putative biological function of candidate genes.ParticipantsFour ERED families, including 28 affected and 17 unaffected individuals.MethodsHumanLinkage-12 arrays (Illumina, San Diego, CA) were used to genotype 17 family members. Next-generation exome sequencing was performed on an uncle–niece pair. Segregation of potential causative mutations was confirmed using Sanger sequencing. Protein expression was determined using immunohistochemistry in human and zebrafish cornea. Gene expression in zebrafish was assessed using whole-mount in situ hybridization. Morpholino-induced transient gene knockdown was performed in zebrafish embryos.Main Outcome MeasuresLinkage microarray, exome analysis, DNA sequence analysis, immunohistochemistry, in situ hybridization, and morpholino-induced genetic knockdown results.ResultsLinkage microarray analysis identified a candidate region on chromosome chr10:12,576,562–112,763,135, and exploration of exome sequencing data identified 8 putative pathogenic variants in this linkage region. Two variants segregated in 06NZ–TRB1 with ERED: COL17A1 c.3156C→T and DNAJC9 c.334G→A. The COL17A1 c.3156C→T variant segregated in all 4 ERED families. We showed biologically relevant expression of these proteins in human cornea. Both proteins are expressed in the cornea of zebrafish embryos and adults. Zebrafish lacking Col17a1a and Dnajc9 during development show no gross corneal phenotype.ConclusionsThe COL17A1 c.3156C→T variant is the likely causative mutation in our recurrent corneal erosion families, and its presence in 4 independent families suggests that it is prevalent in ERED. This same COL17A1 c.3156C→T variant recently was identified in a separate pedigree with ERED. Our study expands the phenotypic spectrum of COL17A1 disease from autosomal recessive epidermolysis bullosa to autosomal dominant ERED and identifies COL17A1 as a key protein in maintaining integrity of the corneal epithelium

    The Swift X-ray Telescope

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    The Swift Gamma-Ray Explorer is designed to make prompt multiwavelength observations of Gamma-Ray Bursts (GRBs) and GRB afterglows. The X-ray Telescope (XRT) enables Swift to determine GRB positions with a few arcseconds accuracy within 100 seconds of the burst onset. The XRT utilizes a mirror set built for JET-X and an XMM/EPIC MOS CCD detector to provide a sensitive broad-band (0.2-10 keV) X-ray imager with effective area of > 120 cm^2 at 1.5 keV, field of view of 23.6 x 23.6 arcminutes, and angular resolution of 18 arcseconds (HPD). The detection sensitivity is 2x10^-14 erg cm^-2 s^-1 in 10^4 seconds. The instrument is designed to provide automated source detection and position reporting within 5 seconds of target acquisition. It can also measure the redshifts of GRBs with Fe line emission or other spectral features. The XRT operates in an auto-exposure mode, adjusting the CCD readout mode automatically to optimize the science return for each frame as the source intensity fades. The XRT will measure spectra and lightcurves of the GRB afterglow beginning about a minute after the burst and will follow each burst for days or weeks.Comment: 36 pages, 24 figure

    Separation of river network–scale nitrogen removal among the main channel and two transient storage compartments

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    Author Posting. © American Geophysical Union, 2011. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Water Resources Research 47 (2011): W00J10, doi:10.1029/2010WR009896.Transient storage (TS) zones are important areas of dissolved inorganic nitrogen (DIN) processing in rivers. We assessed sensitivities regarding the relative impact that the main channel (MC), surface TS (STS), and hyporheic TS (HTS) have on network denitrification using a model applied to the Ipswich River in Massachusetts, United States. STS and HTS connectivity and size were parameterized using the results of in situ solute tracer studies in first- through fifth-order reaches. DIN removal was simulated in all compartments for every river grid cell using reactivity derived from Lotic Intersite Nitrogen Experiment (LINX2) studies, hydraulic characteristics, and simulated discharge. Model results suggest that although MC-to-STS connectivity is greater than MC-to-HTS connectivity at the reach scale, at basin scales, there is a high probability of water entering the HTS at some point along its flow path through the river network. Assuming our best empirical estimates of hydraulic parameters and reactivity, the MC, HTS, and STS removed approximately 38%, 21%, and 14% of total DIN inputs during a typical base flow period, respectively. There is considerable uncertainty in many of the parameters, particularly the estimates of reaction rates in the different compartments. Using sensitivity analyses, we found that the size of TS is more important for DIN removal processes than its connectivity with the MC when reactivity is low to moderate, whereas TS connectivity is more important when reaction rates are rapid. Our work suggests a network perspective is needed to understand how connectivity, residence times, and reactivity interact to influence DIN processing in hierarchical river systems.This work was supported by the National Science Foundation through DEB- 0614282, BCS-0709685 and the Plum Island Long Term Ecological Research site (NSF OCE-0423565)

    Act now against new NHS competition regulations: an open letter to the BMA and the Academy of Medical Royal Colleges calls on them to make a joint public statement of opposition to the amended section 75 regulations.

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