bluuebunny/crossref_metadata_2025_split huggingface dataset:
Wave Cycle Design for NOx-Limited Wave Rotor Core Engines for High Speed Propulsion
Authors: Nalim M. Razi , Mocsari Jeffrey C. , Resler Edwin L. 
Published: February 2015

Direct work and pressure exchange between gases can be accomplished by cyclic wave processes in the channels of a wave-rotor, circumventing the limitations of turbo-compressors. A wave-rotor cycle is presented for use as the high-pressure core in a high speed aircraft engine with turbine bypass. The products of a “low-NOx” combustor undergo a large immediate wave-expansion to reach a permissible turbine blade temperature. The wave rotor provides a substantial increase in pressure ratio and peak cycle temperature resulting in high specific power and efficiency.
Approximate analytical methods are employed for initial design and optimization of the cycle. The method of characteristics is then used to compute the detailed time evolution of the flow-field in a wave channel.
Analysis of High Mach 2DCD and SERN Scale Model Test Data
Authors: Hoff G. E. , Whittaker R. W. 
Published: February 2015

This paper presents the results of analysis of scale model cold flow static performance test data for 2DCD and SERN High Mach (4 to 6) nozzle configurations generated under a GE Aircraft Engines Independent Research and Development Program. The testing was conducted at FluiDyne Engineering Corporation in late 1989. For the 2DCD nozzles, throat area, divergent flap length, contour, expansion ratio, and nozzle pressure ratio were parametrically varied and simulated operating conditions from subsonic to Mach 6. SERN nozzle parameters varied included throat area, expansion ramp length, cowl length and cowl divergence angle. Geometrics and nozzle pressure ratios simulated subsonic to Mach 6 operation. Although these tests were conducted statically, i.e., external flow was not simulated, the analysis presented herein addresses design point performance where the internal performance is not expected to be significantly influenced by external flow.
Data from the test program have been examined for comparison with existing GE performance prediction methods. A second objective was to explore generalization of the data for the preparation of prediction methodologies and design guides for future High Mach propulsion system studies. In general, the study results presented in this paper indicate that current GE 2DCD prediction methods do not extrapolate to the High Mach nozzle regime. Also presented are general performance trends as a function of key geometric parameters and potential correlating factors which provide guidelines for the design of future High Mach exhaust systems.
A method for modeling laterally asymmetric proton beamlets resulting from collimation
Authors: Gelover Edgar , Wang Dongxu , Hill Patrick M. , Flynn Ryan T. , Gao Mingcheng , Laub Steve , Pankuch Mark , Hyer Daniel E. 
Published: February 2015

Purpose:To introduce a method to model the 3D dose distribution of laterally asymmetric proton beamlets resulting from collimation. The model enables rapid beamlet calculation for spot scanning (SS) delivery using a novel penumbra‐reducing dynamic collimation system (DCS) with two pairs of trimmers oriented perpendicular to each other.Methods:Trimmed beamlet dose distributions in water were simulated with MCNPX and the collimating effects noted in the simulations were validated by experimental measurement. The simulated beamlets were modeled analytically using integral depth dose curves along with an asymmetric Gaussian function to represent fluence in the beam's eye view (BEV). The BEV parameters consisted of Gaussian standard deviations (sigmas) along each primary axis (σx1,σx2,σy1,σy2) together with the spatial location of the maximum dose (μx,μy). Percent depth dose variation with trimmer position was accounted for with a depth‐dependent correction function. Beamlet growth with depth was accounted for by combining the in‐air divergence with Hong's fit of the Highland approximation along each axis in the BEV.Results:The beamlet model showed excellent agreement with the Monte Carlo simulation data used as a benchmark. The overall passing rate for a 3D gamma test with 3%/3 mm passing criteria was 96.1% between the analytical model and Monte Carlo data in an example treatment plan.Conclusions:The analytical model is capable of accurately representing individual asymmetric beamlets resulting from use of the DCS. This method enables integration of the DCS into a treatment planning system to perform dose computation in patient datasets. The method could be generalized for use with any SS collimation system in which blades, leaves, or trimmers are used to laterally sharpen beamlets.
Thermally Forced Convection over a Mountainous Tropical Island
Authors: Wang Chun-Chih , Kirshbaum Daniel J. 
Published: February 2015

Abstract
Observations from the Dominica Experiment (DOMEX) and cloud-resolving numerical simulations are used to study a thermally forced convection event over the Caribbean island of Dominica on 18 April 2011. A clear diurnal cycle of island thermal forcing and cumulus convection was observed, with cumuli initiating over the southwestern flank of the ridge and deepening as they drifted eastward. Apart from errors in cloud fraction and (notably) precipitation, the simulations verified well against the observations, provided horizontal grid spacings of 500 m or less were used. The simulated flows developed an island-scale solenoidal circulation with an organized and intense updraft over the ridge that focused convective initiation. Sensitivity tests investigated the impacts of topographic forcing, subcloud winds, and cloud–radiative feedbacks on the island-scale horizontal inflow and cloud vertical mass flux. These experiments confirmed that thermal forcing drove the island convection and that the inflow and cloud mass flux were maximized under weak ambient cross-island winds. The simulations also indicated that cloud shading and precipitation each reduced the island inflow by ~20% while cloud latent heat release enhanced it by ~20%. However, precipitation caused a much smaller reduction in cloud mass flux (10%) than did cloud shading (50%) owing to effective secondary convective initiation by subcloud cold pools. Thermodynamic heat-engine theory provided accurate predictions of the simulated solenoidal updraft magnitudes in selected cases. It also provided a simple explanation for the weakening of the simulated thermal circulation in the presence of island orography: a shallower mixed layer reduced the efficiency of the thermal circulation.
Correction of Excessive Precipitation over Steep and High Mountains in a GCM: A Simple Method of Parameterizing the Thermal Effects of Subgrid Topographic Variation
Authors: Chao Winston C. 
Published: February 2015

Abstract
The excessive precipitation over steep and high mountains (EPSM) in GCMs and mesoscale models is due to a lack of parameterization of the thermal effects of subgrid-scale topographic variation. These thermal effects drive subgrid-scale heated-slope-induced vertical circulations (SHVC). SHVC provide a ventilation effect of removing heat from the boundary layer of resolvable-scale mountain slopes and depositing it higher up. The lack of SHVC parameterization is the cause of EPSM. The author has previously proposed a method of parameterizing SHVC, here termed SHVC.1. Although this has been successful in avoiding EPSM, the drawback is that it suppresses convective-type precipitation in the regions where it is applied.
In this article, the author proposes a new method of parameterizing SHVC, here termed SHVC.2. In SHVC.2, the potential temperature and mixing ratio of the boundary layer are changed when used as input to the cumulus parameterization scheme over mountainous regions. This allows the cumulus parameterization to assume the additional function of SHVC parameterization. SHVC.2 has been tested in NASA Goddard’s GEOS-5 GCM. It achieves the primary goal of avoiding EPSM while also avoiding the suppression of convective-type precipitation in the regions where it is applied.
The Role of Temperature Inversions in the Generation of Seasonal and Interannual SST Variability in the Far Northern Bay of Bengal
Authors: Nagura Motoki , Terao Toru , Hashizume Masahiro 
Published: February 2015

Abstract
The northern Bay of Bengal is characterized by freshwater supply from the Ganges and Brahmaputra Rivers. The resulting shallow haline stratification and thick barrier layer lead to temperature inversions in fall and winter, that is, cool surface water overlaying warm subsurface water. This study examines sea surface temperature (SST) variability off Bangladesh and shows that temperature inversions play an essential role in generating seasonal and interannual SST variability there. Two satellite SST datasets reveal that the magnitude of SST variability has a local peak near the coast of Bangladesh on seasonal and interannual time scales. Output from a high-resolution ocean general circulation model, which is validated by satellite SST and Argo float observations, is used to calculate the mixed layer heat budget. Results show that inverted temperature profiles lead to SST warming on the seasonal time scale via heat exchange at the bottom of the mixed layer, which balances climatological atmospheric cooling in fall and winter. On interannual time scales, surface heat flux tends to damp SST variability, whereas heat exchange at the base of the mixed layer contributes to the growth of SST anomalies. SST off Bangladesh tends to be anomalously high in the year after an El Niño event and in the year of negative Indian Ocean dipole and La Niña events. The atmospheric circulations related to these climate modes force anomalous Ekman pumping, which advects more subsurface warm water to the surface in fall and winter, resulting in anomalous mixed layer warming. The deepening of the mixed layer entrains more subsurface warm water, which also contributes to anomalous warming.
Data-Enabled Field Experiment Planning, Management, and Research Using Cyberinfrastructure
Authors: Demir Ibrahim , Conover Helen , Krajewski Witold F. , Seo Bong-Chul , Goska Radosław , He Yubin , McEniry Michael F. , Graves Sara J. , Petersen Walter 
Published: February 2015

AbstractIn the spring of 2013, NASA conducted a field campaign known as Iowa Flood Studies (IFloodS) as part of the Ground Validation (GV) program for the Global Precipitation Measurement (GPM) mission. The purpose of IFloodS was to enhance the understanding of flood-related, space-based observations of precipitation processes in events that transpire worldwide. NASA used a number of scientific instruments such as ground-based weather radars, rain and soil moisture gauges, stream gauges, and disdrometers to monitor rainfall events in Iowa. This article presents the cyberinfrastructure tools and systems that supported the planning, reporting, and management of the field campaign and that allow these data and models to be accessed, evaluated, and shared for research. The authors describe the collaborative informatics tools, which are suitable for the network design, that were used to select the locations in which to place the instruments. How the authors used information technology tools for instrument monitoring, data acquisition, and visualizations after deploying the instruments and how they used a different set of tools to support data analysis and modeling after the campaign are also explained. All data collected during the campaign are available through the Global Hydrology Resource Center (GHRC), a NASA Distributed Active Archive Center (DAAC).
An engineered micropattern to reduce bacterial colonization, platelet adhesion and fibrin sheath formation for improved biocompatibility of central venous catheters
Authors: May Rhea M , Magin Chelsea M , Mann Ethan E , Drinker Michael C , Fraser John C , Siedlecki Christopher A , Brennan Anthony B , Reddy Shravanthi T 
Published: February 2015

AbstractBackgroundCatheter‐related bloodstream infections (CRBSIs) and catheter‐related thrombosis (CRT) are common complications of central venous catheters (CVC), which are used to monitor patient health and deliver medications. CVCs are subject to protein adsorption and platelet adhesion as well as colonization by the natural skin flora (i.e. Staphylococcus aureus and Staphylococcus epidermidis). Antimicrobial and antithrombotic drugs can prevent infections and thrombosis‐related complications, but have associated resistance and safety risks. Surface topographies have shown promise in limiting platelet and bacterial adhesion, so it was hypothesized that an engineered Sharklet micropattern, inspired by shark‐skin, may provide a combined approach as it has wide reaching anti‐fouling capabilities. To assess the feasibility for this micropattern to improve CVC‐related healthcare outcomes, bacterial colonization and platelet interactions were analyzed in vitro on a material common for vascular access devices.MethodsTo evaluate bacterial inhibition after simulated vascular exposure, micropatterned thermoplastic polyurethane surfaces were preconditioned with blood proteins in vitro then subjected to a bacterial challenge for 1 and 18 h. Platelet adhesion was assessed with fluorescent microscopy after incubation of the surfaces with platelet‐rich plasma (PRP) supplemented with calcium. Platelet activation was further assessed by monitoring fibrin formation with fluorescent microscopy after exposure of the surfaces to platelet‐rich plasma (PRP) supplemented with calcium in a flow‐cell. Results are reported as percent reductions and significance is based on t‐tests and ANOVA models of log reductions. All experiments were replicated at least three times.ResultsBlood and serum conditioned micropatterned surfaces reduced 18 h S. aureus and S. epidermidis colonization by 70% (p ≤ 0.05) and 71% (p < 0.01), respectively, when compared to preconditioned unpatterned controls. Additionally, platelet adhesion and fibrin sheath formation were reduced by 86% and 80% (p < 0.05), respectively, on the micropattern, when compared to controls.ConclusionsThe Sharklet micropattern, in a CVC‐relevant thermoplastic polyurethane, significantly reduced bacterial colonization and relevant platelet interactions after simulated vascular exposure. These results suggest that the incorporation of the Sharklet micropattern on the surface of a CVC may inhibit the initial events that lead to CRBSI and CRT.
Effects of ferumoxytol on quantitative PET measurements in simultaneous PET/MR whole-body imaging: a pilot study in a baboon model
Authors: Borra Ronald JH , Cho Hoon-Sung , Bowen Spencer L , Attenberger Ulrike , Arabasz Grae , Catana Ciprian , Josephson Lee , Rosen Bruce R , Guimaraes Alexander R , Hooker Jacob M 
Published: February 2015

AbstractBackgroundSimultaneous PET/MR imaging depends on MR-derived attenuation maps (mu-maps) for accurate attenuation correction of PET data. Currently, these maps are derived from gradient-echo-based MR sequences, which are sensitive to susceptibility changes. Iron oxide magnetic nanoparticles have been used in the measurement of blood volume, tumor microvasculature, tumor-associated macrophages, and characterizing lymph nodes. Our aim in this study was to assess whether the susceptibility effects associated with iron oxide nanoparticles can potentially affect measured18F-FDG PET standardized uptake values (SUV) through effects on MR-derived attenuation maps.MethodsThe study protocol was approved by the Institutional Animal Care and Use Committee. Using a Siemens Biograph mMR PET/MR scanner, we evaluated the effects of increasing concentrations of ferumoxytol and ferumoxytol aggregates on MR-derived mu-maps using an agarose phantom. In addition, we performed a baboon experiment evaluating the effects of a single i.v. ferumoxytol dose (10 mg/kg) on the liver, spleen, and pancreas18F-FDG SUV at baseline (ferumoxytol-naïve), within the first hour and at 1, 3, 5, and 11 weeks.ResultsPhantom experiments showed mu-map artifacts starting at ferumoxytol aggregate concentrations of 10 to 20 mg/kg. Thein vivobaboon data demonstrated a 53% decrease of observed18F-FDG SUV compared to baseline within the first hour in the liver, persisting at least 11 weeks.ConclusionsA single ferumoxytol dose can affect measured SUV for at least 3 months, which should be taken into account when administrating ferumoxytol in patients needing sequential PET/MR scans.Advances in knowledge1. Ferumoxytol aggregates, but not ferumoxytol alone, produce significant artifacts in MR-derived attenuation correction maps at approximate clinical dose levels of 10 mg/kg.2. When performing simultaneous whole-body18F-FDG PET/MR, a single dose of ferumoxytol can result in observed SUV decreases up to 53%, depending on the amount of ferumoxytol aggregates in the studied tissue.Implications for patient careAdministration of a single, clinically relevant, dose of ferumoxytol can potentially result in changes in observed SUV for a prolonged period of time in the setting of simultaneous PET/MR. These potential changes should be considered in particular when administering ferumoxytol to patients with expected future PET/MR studies, as ferumoxytol-induced SUV changes might interfere with therapy assessment.
The human β-amyloid precursor protein: biomolecular and epigenetic aspects
Authors: Nguyen Khue Vu 
Published: February 2015

AbstractBeta-amyloid precursor protein (APP) is a membrane-spanning protein with a large extracellular domain and a much smaller intracellular domain. APP plays a central role in Alzheimer’s disease (AD) pathogenesis: APP processing generates β-amyloid (Aβ) peptides, which are deposited as amyloid plaques in the brains of AD individuals; point mutations and duplications ofAPPare causal for a subset of early-onset familial AD (FAD) (onset age <65 years old). However, these mutations in FAD represent a very small percentage of cases (∼1%). Approximately 99% of AD cases are nonfamilial and late-onset, i.e., sporadic AD (SAD) (onset age >65 years old), and the pathophysiology of this disorder is not yet fully understood. APP is an extremely complex molecule that may be functionally important in its full-length configuration, as well as the source of numerous fragments with varying effects on neural function, yet the normal function of APP remains largely unknown. This article provides an overview of our current understanding of APP, including its structure, expression patterns, proteolytic processing and putative functions. Importantly, and for the first time, my recent data concerning its epigenetic regulation, especially in alternative APP pre-mRNA splicing and in the control of genomic rearrangements of theAPPgene, are also reported. These findings may provide new directions for investigating the role of APP in neuropathology associated with a deficiency in the enzyme hypoxanthine-guanine phosphoribosyltransferase (HGprt) found in patients with Lesch-Nyhan syndrome (LNS) and its attenuated variants (LNVs). Also, these findings may be of significance for research in neurodevelopmental and neurodegenerative disorders in which the APP gene is involved in the pathogenesis of diseases such as autism, fragile X syndrome (FXS) and AD, with its diversity and complexity, SAD in particular. Accurate quantification of various APP-mRNA isoforms in brain tissues is needed, and antisense drugs are potential treatments.
Impact of Coil Geometry on Magnetohydrodynamic Flow in Liquid Aluminium and Its Relevance to Inclusion Separation by Electromagnetophoresis
Authors: Kennedy Mark William , Bakken Jon Arne , Aune Ragnhild Elizabeth 
Published: February 2015

AbstractMagnetohydrodynamic (MHD) flow will be produced in liquid aluminium by gradients in the Lorentz forces created by the interactions of induced currents and the time-varying magnetic field of an induction coil. The magnitude of the velocity field is driven by the curl of the Lorentz forces. Practical coils are “Short” and produce magnetic fields having both lower flux densities and Lorentz forces than very “Long” or infinite coils. Unlike infinite coils, the magnetic fields of “Short” coils contain both axial and radial components, which vary with position and thereby produce powerful MHD mixing. When such a coil is used with the objective of achieving non-conductive particle migration in a liquid metal by electromagnetophoresis, the obtained mixing effects can be highly detrimental. In the present study different coil geometries and induced Lorentz forces with resulting MHD mixing are modelled (COMSOL®4.4), and the obtained Lorentz forces compared to analytical results.
Alsatian versus Standard German: Regional Language Bilingual Primary Education in Alsace
Authors: Harrison Michelle Anne 
Published: February 2015

Abstract
This article examines the current situation of regional language bilingual primary education in Alsace and contends that the regional language presents a special case in the context of France. The language comprises two varieties: Alsatian, which traditionally has been widely spoken, and Standard German, used as the language of reference and writing. The advantages of learning Standard German have been highlighted by language-in-education policy-makers: as well as being the written form of the regional language, German is promoted as the most widely spoken language in the European Union, the language of neighbouring countries, an asset in the search for employment and an aid to learning another powerful language in our increasingly globalized world, namely English. Nevertheless, Alsatian can be, and in some cases is being, employed in the classroom, although it remains in a minority position in comparison to Standard German. Based on original research undertaken in the region, the article aims to explore current classroom practices, which are sometimes found to be incongruous with official language-in-education policy. It analyses the language attitudes of parents and considers the effect of these attitudes on the promotion of Alsatian and Standard German. Practices and attitudes in city and small town locations are compared to evaluate the influence of urban and peri-urban settings. As the transmission of Alsatian is no longer guaranteed in the home, the article investigates whether the school can promote this traditional, non-standardized regional variety alongside the dominant standard languages, and whether parents wish for this to happen.