8th Annual NNSA-IRSN PCG on PAS-PP02 and Proposed Action Sheet AS8.
Abstract not provided.
Snell, Mark K.↗
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Texture analysis of placental MRI: can it aid in the prenatal diagnosis of placenta accreta spectrum?
Purpose: To determine if texture analysis can differentiate placenta accreta spectrum (PAS) from normal placenta on MRI. Methods: We performed retrospective image analysis of 80 patients, comprised of 46 patients with PAS and 34 patients without PAS. Histopathology was used as the reference standard. Sagittal single shot fast spin echo T2-weighted MRI sequences acquired from a single institution were analyzed. Placental heterogeneity was quantified using in-house software on a Matlab platform, including the standard deviation of pixel intensity, coefficient of variation, gray-level co-occurrence matrices (GLCM), histogram-oriented gradients (HOG), and fractal analysis with box sizes from 2 to 512. Two-tailed unpaired Student’s t test was used with statistical significance of p < 0.05. Results: PAS was associated with higher values for standard deviation of pixel intensity and fractal analysis at every box size. Fractal analysis at box sizes 256 (p = 0.011) and 32 (p = 0.021), and standard deviation of pixel intensity (p = 0.023) were the most statistically significant. Fractal values at box size 256 for PAS was 0.13 versus 0.090 for patients without PAS, while standard deviation of pixel intensity was 3.7 for PAS versus 2.5 for patients without PAS. No statistically significant association between PAS and GLCM, coefficient of variation, and HOG was found. Conclusion: Statistically significant differences were found between normal and abnormal groups using standard deviation of pixel intensity and fractal analysis.
62 RADIOLOGY AND NUCLEAR MEDICINE↗
The Use of Positrons to Survey Alteration Layers on Synthetic Nuclear Waste Glasses
In order to safeguard society and the environment, understanding radioactive waste glass alteration mechanisms in interactions with solutions and near-field materials, such as Fe, is essential to nuclear waste repository performance assessments. Alteration products are formed at the surface of glasses after reaction with solution. In this study, glass altered in the presence of Fe0 in aqueous solution formed two alteration layers: one embedded with Fe closer to the surface and one without Fe found deeper in the sample. Both layers were found to be thinner than the alteration layer found in glass altered in aqueous solution only. For the first time, Doppler Broadening Positron Annihilation Spectroscopy (DB-PAS) is used to non-destructively characterize the pore structures of glass altered in the presence of Fe0. Advantages and disadvantages of DB-PAS compared to other techniques used to analyze pore structures for altered glass samples are discussed. Ultimately, DB-PAS has shown to be an excellent choice for pore structure characterization for glasses with multiple alteration layers. Monte Carlo modeling predicted positron trajectories through the layers, and helped explain DB-PAS data, which showed that the deeper alteration layer without Fe had a similar composition and pore structure to layers on glass altered in water only.
Doppler Broadening Positron Annihilation Spectrosc↗
A Framework to Delineate Precipitation-Runoff Regimes: Precipitation vs. Snowpack in the Western U.S.
We propose a framework to classify precipitation events accompanied by snow process (precipitation-and-snow, or PAS events) into five regimes, based on the relative contributions of snowpack change and precipitation amount to the runoff response. This framework is applied to a regional climate simulation over the western U.S. to reveal the regions where snow process plays important roles. Over the western U.S., PAS events account for 50-90% of all the precipitation events. About 60-80% of PAS events feature snow accumulation, but snow melting frequently happens in high-elevation areas. Compared with snow accumulation events, snow melting events have a more limited spatial distribution. Different regimes peak in different months between early winter and late spring. Lastly, the impact of atmospheric rivers is investigated. Although accounting for only 2% of the grid-scale precipitation events, atmospheric rivers trigger significant snowmelt and contribute to 20% and 11% of light and heavy snow melting events, respectively.
Chen, Xiaodong↗
Coiled-coil coactivators play a structural role mediating interactions in hypoxia-inducible factor heterodimerization
The hypoxia-inducible factor complex (HIF-α·aryl hydrocarbon receptor nuclear translocator (ARNT)) requires association with several transcription coactivators for a successful cellular response to hypoxic stress. In addition to the conventional global transcription coactivator CREB-binding protein/p300 (CBP/p300) that binds to the HIF-α transactivation domain, a new group of transcription coactivators called the coiled-coil coactivators (CCCs) interact directly with the second PER-ARNT-SIM (PAS) domain of ARNT (ARNT PAS-B). These less studied transcription coactivators play essential roles in the HIF-dependent hypoxia response, and CCC misregulation is associated with several forms of cancer. To better understand CCC protein recruitment by the heterodimeric HIF transcription factor, we used x-ray crystallography, NMR spectroscopy, and biochemical methods to investigate the structure of the ARNT PAS-B domain in complex with the C-terminal fragment of a coiled-coil coactivator protein, transforming acidic coiled-coil coactivator 3 (TACC3). We found that the HIF-2α PAS-B domain also directly interacts with TACC3, motivating an NMR data-derived model suggesting a means by which TACC3 could form a ternary complex with HIF-2α PAS-B and ARNT PAS-B via β-sheet/coiled-coil interactions. Furthermore, these findings suggest that TACC3 could be recruited as a bridge to cooperatively mediate between the HIF-2α PAS-B·ARNT PAS-B complex, thereby participating more directly in HIF-dependent gene transcription than previously anticipated.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Mechanochemistry of Phosphorus and Arsenic Alloys for Visible and Infrared Photonics
Incorporating few‐layer 2D phosphorus–arsenic alloys (PAs) into optoelectronic devices requires a synthesis technique that allows control of the alloy composition while producing volumes of material suitable for application development such as photodetectors, solar cells, and lasers. With that goal in mind, high‐energy ball milling allows production of both orthorhombic (o‐PAs) and trigonal (t‐PAs) alloys by reacting red phosphorus and metallic arsenic powders. The synthesis follows a two‐step process in which arsenic rapidly reacts with red phosphorus to first produce t‐PAs followed by a slower phase transformation into o‐PAs; synthesis time and overall conversion rate are slightly enhanced by the presence of arsenic. Optical measurements on exfoliated alloys at the few‐layer atomic limit of the 2D PAs reveal emission spanning from the visible (≈1.9 eV) into the near‐infrared region, covering a broad application space. Rapid powder synthesis within a closed system for stochiometric control of the solid‐solution PAs alloys combined with solution‐based exfoliation opens up opportunities for a whole new class of optoelectronic devices based on PA nanomaterials.
Pedersen, Samuel V.↗
The role of protected areas in land use/land cover change and the carbon cycle in the conterminous United States
Protected areas (PAs) cover about 22% of the conterminous United States. Understanding their role on historical land use and land cover change (LULCC) and on the carbon cycle is essential to provide guidance for environmental policies. In this study, we compiled historical LULCC and PAs data to explore these interactions within the terrestrial ecosystem model (TEM). We found that intensive LULCC occurred in the conterminous United States from 1700 to 2005. More than 3 million km2 of forest, grassland and shrublands were converted into agricultural lands, which caused 10,607 Tg C release from land ecosystems to atmosphere. PAs had experienced little LULCC as they were generally established in the 20th century after most of the agricultural expansion had occurred. PAs initially acted as a carbon source due to land use legacies, but their accumulated carbon budget switched to a carbon sink in the 1960s, sequestering an estimated 1,642 Tg C over 1700–2005, or 13.4% of carbon losses in non-PAs. We also find that PAs maintain larger carbon stocks and continue sequestering carbon in recent years (2001–2005), but at a lower rate due to increased heterotrophic respiration as well as lower productivity associated to aging ecosystems. It is essential to continue efforts to maintain resilient, biodiverse ecosystems and avoid large-scale disturbances that would release large amounts of carbon in PAs.
Lu, Xiaoliang↗
Formation of a repressive complex in the mammalian circadian clock is mediated by the secondary pocket of CRY1
The basic helix-loop-helix PAS domain (bHLH-PAS) transcription factor CLOCK:BMAL1 (brain and muscle Arnt-like protein 1) sits at the core of the mammalian circadian transcription/translation feedback loop. Precise control of CLOCK:BMAL1 activity by coactivators and repressors establishes the ~24-h periodicity of gene expression. Formation of a repressive complex, defined by the core clock proteins cryptochrome 1 (CRY1):CLOCK:BMAL1, plays an important role controlling the switch from repression to activation each day. Here in this paper, we show that CRY1 binds directly to the PAS domain core of CLOCK: BMAL1, driven primarily by interaction with the CLOCK PAS-B domain. Integrative modeling and solution X-ray scattering studies unambiguously position a key loop of the CLOCK PAS-B domain in the secondary pocket of CRY1, analogous to the antenna chromophore-binding pocket of photolyase. CRY1 docks onto the transcription factor alongside the PAS domains, extending above the DNA-binding bHLH domain. Single point mutations at the interface on either CRY1 or CLOCK disrupt formation of the ternary complex, highlighting the importance of this interface for direct regulation of CLOCK:BMAL1 activity by CRY1.
60 APPLIED LIFE SCIENCES↗
Atheroma Niche-Responsive Nanocarriers for Immunotherapeutic Delivery
Nanomedicine is a promising, noninvasive approach to reduce atherosclerotic plaque burden. However, drug delivery is limited without the ability of nanocarriers to sense and respond to the diseased microenvironment. Here, nanomaterials are developed from peptide amphiphiles (PAs) that respond to the increased levels of matrix metalloproteinases 2 and 9 (MMP2/9) or reactive oxygen species (ROS) found within the atherosclerotic niche. A pro-resolving therapeutic, Ac2-26, derived from annexin-A1 protein, is tethered to PAs using peptide linkages that cleave in response to MMP2/9 or ROS. By adjusting the molar ratios and processing conditions, the Ac2-26 PA can be co-assembled with a PA containing an apolipoprotein A1-mimetic peptide to create a targeted, therapeutic nanofiber (ApoA1-Ac226 PA). The ApoA1-Ac2-26 PAs demonstrate release of Ac2-26 within 24 h after treatment with MMP2 or ROS. The niche-responsive ApoA1-Ac2-26 PAs are cytocompatible and reduce macrophage activation from interferon gamma and lipopolysaccharide treatment, evidenced by decreased nitric oxide production. Interestingly, the linkage chemistry of ApoA1-Ac2-26 PAs significantly affects macrophage uptake and retention. Taken together, these findings demonstrate the potential of PAs to serve as an atheroma niche-responsive nanocarrier system to modulate the inflammatory microenvironment, with implications for atherosclerosis treatment.
60 APPLIED LIFE SCIENCES↗
Equatorial coordination of uranyl: Correlating ligand charge donation with the O yl -U-O yl asymmetric stretch frequency
In uranyl coordination complexes, UO 2 (L) n 2+ , uranium in the formally dipositive [O=U=O] 2+ moiety is coordinated by n neutral organic electron donor ligands, L. The extent of ligand electron donation, which results in partial reduction of uranyl and weakening of the U=O bonds, is revealed by the magnitude of the red-shift of the uranyl asymmetric stretch frequency, ν 3 . This phenomenon appears in gas-phase complexes in which uranyl is coordinated by electron donor ligands: the ν 3 red-shift increases as the number of ligands and their proton affinity (PA) increases. Because PA is a measure of the enthalpy change associated with a proton-ligand interaction, which is much stronger and of a different nature than metal ion-ligand bonding, it is not necessarily expected that ligand PAs should reliably predict uranyl-ligand bonding and the resulting ν 3 red-shift. In this study, ν 3 was measured for uranyl coordinated by ligands with a relatively broad range of PAs, revealing a surprisingly good correlation between PA and ν 3 frequency. From computed ν 3 frequencies for bare UO 2 cations and neutrals, it is inferred that the effective charge of uranyl in UO 2 (L) n 2+ complexes can be reduced to near zero upon ligation by sufficiently strong charge-donor ligands. The basis for the correlation between ν 3 and ligand PAs, as well as limitations and deviations from it, are considered. It is demonstrated that the correlation evidently extends to a ligand that exhibits polydentate metal ion coordination.
Gibson, John K.↗
1‐Formyl‐7‐hydroxy‐6,7‐dihydro‐5 H ‐pyrrolizine (9‐CHO‐DHP) ‐ A Biologically Proximate Pyrrolic Metabolite of Carcinogenic Pyrrolizidine Alkaloids
Pyrrolizidine alkaloids (PAs) are phytochemical constituents of more than 6000 plant species worldwide; approximately half of the PAs are hepatotoxic, genotoxic, and carcinogenic. Because of their wide exposure and carcinogenicity, the International Programme on Chemical Safety (IPCS) concluded that PAs are a threat to human health and safety. We recently determined that the metabolic activation pathway of PA‐induced liver tumor initiation is mediated by a set of four (±)‐6,7‐dihydro‐7‐hydroxy‐1‐hydroxymethyl‐5H‐pyrrolizine (DHP)‐derived DNA adducts, and proposed that these DHP‐DNA adducts are potential biomarkers of PA exposure and liver tumor initiation. To validate the generality of this metabolic activation pathway and DHP‐DNA adducts as biomarkers, it is important to identify the spectrum of reactive metabolites associated with this metabolic activation pathway. Segall et al. ( Drug Metab. Disposit. , 12, 68–71, 1984) reported that 1‐formyl‐7‐hydroxy‐6,7‐dihydro‐5 H ‐pyrrolizine (9‐CHO‐DHP) is a metabolite formed from the mouse liver microsomal metabolism of senecionine. In this present study, we examined the metabolism of six hepatocarcinogenic PAs (riddelliine, senecionine, monocrotaline, senkirkine, intermedine, and heliotrine) and one non‐carcinogenic PA (platphylline) by human, rat, and mouse liver microsomes. 9‐CHO‐DHP was found as a common metabolite from the metabolism of the six hepatotoxic PAs, but not from platphylline. Incubation of 9‐CHO‐DHP in HepG2 cells and A549 cells resulted in the formation of the same set of DHP‐DNA adducts, as assessed by both LC/MS SRM mode and selected ion monitoring analyses through comparison to synthetic standards. In the incubation medium of HepG2 cells, both DHP and 7‐cysteine‐DHP were identified. These metabolites have previously shown to be capable of binding to cellular DNA to produce DHP‐DNA adducts. Thus, when incubated with HepG2 cells, 9‐CHO‐DHP was metabolized to the reactive metabolites DHP and 7‐cysteine‐DHP, metabolites associated with the DHP‐DNA adduct formation. These results indicate that 9‐CHO‐DHP is a DNA proximate metabolite of hepatotoxic PAs and further support the generality of this metabolic activation pathway mediated by the formation of these DHP‐DNA adducts. [This abstract is not an official U.S. Food and Drug Administration (FDA) guidance or policy statement. No offcial support or endorsement by the U.S. FDA is intended or should be inferred. The authors declare no competing financial interest.] Support or Funding Information This research was supported in part by appointment (X.H.) to the Postgraduate Research Program at the NCTR administered by the Oak Ridge Institute for Science and Education through an interagency agreement between the U.S. Department of Energy and the FDA. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .
Xia, Qingsu↗
Application of Remote Sensing for Ex-Ante Decision Support and Evaluating Impact
Deforestation is an environmental stressor that dramatically threatens biodiversity while having adverse, deep-rooted socioeconomic impacts. Interventions to address deforestation require considerable long-term investments; therefore, assessing their impact is crucial. The UN Convention on Biological Diversity encourages establishing Protected Areas (PAs) as a strategy to conserve biodiversity, secure ecosystem services, support local livelihoods, and reduce climate change impacts. The Global Environment Facility (GEF) has supported the conservation and management of PAs, yet site accessibility and data availability present challenges in assessing PAs using traditional evaluation methods. We present a novel application of satellite Earth observations for evaluating the effectiveness and impact of PAs as a deforestation mitigation strategy. Geospatial analysis and ecological forecasting methodologies provide an efficient way to quantify land cover change, estimate above-ground carbon stock, and evaluate ecosystem services provided by the PAs ex-ante. We demonstrate the value of a geospatial approach through evaluation of GEF-supported PAs in Kenya.
Remote sensing↗
Aircraft noise prediction program propeller analysis system IBM-PC version user's manual version 2.0
The IBM-PC version of the Aircraft Noise Prediction Program (ANOPP) Propeller Analysis System (PAS) is a set of computational programs for predicting the aerodynamics, performance, and noise of propellers. The ANOPP-PAS is a subset of a larger version of ANOPP which can be executed on CDC or VAX computers. This manual provides a description of the IBM-PC version of the ANOPP-PAS and its prediction capabilities, and instructions on how to use the system on an IBM-XT or IBM-AT personal computer. Sections within the manual document installation, system design, ANOPP-PAS usage, data entry preprocessors, and ANOPP-PAS functional modules and procedures. Appendices to the manual include a glossary of ANOPP terms and information on error diagnostics and recovery techniques.
Nolan, Sandra K.↗
Pseudo Aircraft Systems - A multi-aircraft simulation system for air traffic control research
Pseudo Aircraft Systems (PAS) is a computerized flight dynamics and piloting system designed to provide a high fidelity multi-aircraft real-time simulation environment to support Air Traffic Control research. PAS is composed of three major software components that run on a network of computer workstations. Functionality is distributed among these components to allow the system to execute fast enough to support real-time operation. PAS workstations are linked by an Ethernet Local Area Network, and standard UNIX socket protocol is used for data transfer. Each component of PAS is controlled and operated using a custom designed Graphical User Interface. Each of these is composed of multiple windows, and many of the windows and sub-windows are used in several of the components. Aircraft models and piloting logic are sophisticated and realistic and provide complex maneuvering and navigational capabilities. PAS will continually be enhanced with new features and improved capabilities to support ongoing and future Air Traffic Control system development.
Weske, Reid A.↗
A Users Guide for the NASA ANOPP Propeller Analysis System
The purpose of this report is to document improvements to the Propeller Analysis System of the Aircraft Noise Prediction Program (PAS-ANOPP) and to serve as a users guide. An overview of the functional modules and modifications made to the Propeller ANOPP system are described. Propeller noise predictions are made by executing a sequence of functional modules through the use of ANOPP control statements. The most commonly used ANOPP control statements are discussed with detailed examples demonstrating the use of each control statement. Originally, the Propeller Analysis System included the angle-of-attack only in the performance module. Recently, modifications have been made to also include angle-of-attack in the noise prediction module. A brief description of PAS prediction capabilities is presented which illustrate the input requirements necessary to run the code by way of ten templates. The purpose of the templates are to provide PAS users with complete examples which can be modified to serve their particular purposes. The examples include the use of different approximations in the computation of the noise and the effects of synchrophasing. Since modifications have been made to the original PAS-ANOPP, comparisons of the modified ANOPP and wind tunnel data are also included. Two appendices are attached at the end of this report which provide useful reference material. One appendix summarizes the PAS functional modules while the second provides a detailed discussion of the TABLE control statement.
Nguygen, L. Cathy↗
The effects of some polyamine biosynthetic inhibitors on growth and morphology of phytopathogenic fungi
We have studied the effects of two polyamine biosynthetic inhibitors, alpha-difluoromethylornithine (DFMO) and alpha-difluoromethylarginine (DFMA), and of polyamines (PAs), alone and in combination, on mycelial growth and morphology of four phytopathogenic fungi: Botrytis sp, B. cinerea, Rhizoctonia solani and Monilinia fructicola. The inhibitors were added to a Czapek agar medium to get final concentrations of 0.1, 0.5 and 1.0 mM. DFMO and DFMA, suicide inhibitors of ornithine decarboxylase (ODC) and arginine decarboxylase (ADC) respectively, inhibited mycelial growth strongly; the effect was generally more pronounced with DFMA than with DFMO, but each fungus had its own response pattern. The addition of the PAs putrescine (Put) and spermidine (Spd) to the culture medium resulted in a promotion of growth. In Botrytis sp and Monilinia fructicola exposed to inhibitors plus PAs, mycelial growth was actually increased above control values. Mycelial morphology was altered and cell size dramatically reduced in plates containing inhibitors alone, whereas with PAs alone, or in combination with inhibitors, morphology was normal, but cell length and diameters increased considerably. These results suggest that PAs are essential for growth in fungal mycelia. The inhibition caused by DFMA may be due to its arginase-mediated conversion to DFMO.
NASA Discipline Plant Biology↗
Power, Avionics and Software - Phase 1.0:
This report describes Power, Avionics and Software (PAS) 1.0 subsystem integration testing and test results that occurred in August and September of 2013. This report covers the capabilities of each PAS assembly to meet integration test objectives for non-safety critical, non-flight, non-human-rated hardware and software development. This test report is the outcome of the first integration of the PAS subsystem and is meant to provide data for subsequent designs, development and testing of the future PAS subsystems. The two main objectives were to assess the ability of the PAS assemblies to exchange messages and to perform audio testing of both inbound and outbound channels. This report describes each test performed, defines the test, the data, and provides conclusions and recommendations.
Communiocations↗
Supervised Autonomous Assembly to Create and Evolve Persistent Assets
Supervised autonomous assembly (SAA) will create a paradigm shift in the planning and design of future persistent assets (PAs), both in near zero-g environments and on planetary surfaces. SAA refers to an autonomy approach that has the benefits of autonomous assembly as well as the benefits provided by a supervisor (operator) who is available to resolve unexpected situations. SAA provides both increased design freedom as well as reduced programmatic risk. SAA enables evolution of future PAs over decades as in-space operations transition from single purpose missions to creation of PAs, such as laboratories and experimental stations which more closely resembling terrestrial laboratories that can easily adapt and evolve to new missions leveraging repeated visits to the PA. The ability to evolve enables PAs to rapidly respond to changing objectives resulting from new questions as our understanding improves. A recently initiated National Aeronautics and Space Administration (NASA) project in the Space Technology Mission Directorate (STMD) Game Changing Development (GCD) Program called the Precision Assembled Space Structure (PASS), leverages the advantages of SAA to develop technologies that enable efficient creation and evolution of hexagonal topologies; both planar (example: fuel depots) and curved (examples: telescopes and shelters). PASS will be used to provide context for the philosophy and concepts discussed as well as the decision and selections made. PASS objectives are: a) Develop confidence in SAA and on-orbit servicing, assembly and manufacturing (OSAM) technologies by executing a test campaign that uses a path-to-flight autonomous precision assembly process directly applicable to future space telescopes. b) Test autonomous technologies including automated path planning and error recovery, to emphasize a robust approach that relies on generic robots and special purpose tools. c) Validate critical component models using a digital twin that includes the assembled primary mirror support structure and assembly process. A digital twin is a high-fidelity simulation of the asset capable of predicting the on-orbit performance. The paper concludes after identifying the critical need for a modest assembly flight experiment to validate and develop confidence in the SAA paradigm, thus accelerating adoption of the benefits described. SAA is a game changing paradigm that enhances the ability of an organization to infuse new technology through rapid evolution of PAs while leveraging OSAM technologies.
Structural Modeling↗