Lifting-line theory for subsonic axial compressor rotors

July 1972Includes bibliographical references (leaf 25)The three-dimensional compressible vortex theory of an axial compressor rotor or ducted fan is extended by relating blade loading to blade geometry in the lifting-line approximation. The resulting integral equation, which is valid up to high subsonic Mach numbers, is solved for both design and off-design problems. It is shown that three-dimensional effects must be taken into account, for rotors with non-uniform spanwise loading, in order to obtain accurate predictions of flow angles and other performance parameters.This Research carried out in the Gas Turbine Laboratory, M.I.T., supported by NASA Lewis Research Center, under Grant No. NGL 22-009-38

Energy Conversion Research

Contains reports on three research projects.U. S. Air Force (Research and Technology Division) under Contract AF33(615)-3489 with the Air Force Aero Propulsion Laboratory, Wright-Patterson Air Force Base, Ohi

Comparison of three dimensional quasi-linear large swirl theory with measured outflow from a high-work compressor rotor

September 1975Includes bibliographical references (page 37)A three-dimensional perturbation theory for incompressible strongly swirling flow in an annulus is applied to predict the outflow from a high-work compressor rotor (1)(2). A comparison of the analytical result with the experimental result is presented. The theory treats inviscid, incompressible flow through a highly loaded blade row in a long annular duct with uniform inlet. Trailing vorticity is shed from each blade which is represented by a lifting line of bound vorticity. The flow field between successive sheets of vorticity is assumed to be irrotational. The theoretical results are compared to data obtained in the M.I.T. Blowdown Compressor Test Facility (3). The mean circulation distribution is estimated from the mean pitchwise Mach number obtained from the experiment. The agreement of the predicted mean axial and radial velocity with the experimental results represents one confirmation of the theory. The pitchwise-varying velocity are evaluated by the theory at an axial distance of .02 tip radius which corresponds to the probe position if the lifting line is placed slightly ahead, but almost along the trailing edge of the blade. The theory predicts well the pitchwise variation of the velocity due to the effect of shed vorticity which results from the spanwise variation of circulation. The effect is pronounced near the blade tips. Corrections of the theory due to compressibility are omitted here, but will be available shortly.Research supported by the Air Office of Scientific Research under Grant AFOSR-75-278

Energy Conversion Research

Contains research objectives and reports on three research projects.U. S. Air Force (Research and Technology Division) under Contract AF33(615)-1083 with the Air Force Aero Propulsion Laboratory, Wright-Patterson Air Force Base, Ohi

Calculation of a self-consistent, low frequency electrostatic field in the drift-kinetic approximation

July 1977Includes bibliographical references (pages 22-23)We derive an asymptotic series in [omega]p -2 , the inverse-square plasma frequency, for the self-consistent, low frequency electrostatic field in tori. The derivation is consistent with the drift-kinetic ordering and may be used in either instability or equilibrium calculations. We find that in a time-dependent formalism, the electric field is completely determined to first order in a drift-kinetic expansion.Research supported by the Energy Research and Development Administration under contract with Union Carbide Corporation and under contract at M.I.T EX-76-A-01-229

Plasma Magnetohydrodynamics and Energy Conversion

Contains reports on seven research projects.U. S. Air Force (Aeronautical Systems Division) under Contract AF33 (615)-1083 with the Air Force Aero Propulsion Laboratory, Wright-Patterson Air Force Base, OhioNational Science Foundation (Grant GK-57

Plasma Dynamics

Contains research objectives and summary of research.U.S. Atomic Energy Commission (Contract AT(11-1)-3070)National Science Foundation (Grant GK-37979X)National Science Foundation (Grant GK-28282X1

A Landscapeâ Based Classification of Fish Assemblages in Sampled and Unsampled Lakes

We related fish species patterns and landscapeâ scale environmental data from 216 Michigan lakes to identify repeatable types of fish assemblages, identify environmental factors related to assemblage types, and classify fish assemblages in unsampled lakes. Multivariate regression tree modeling of fish species abundances identified six assemblage types that were explained by degreeâ days during the iceâ free period, lake surface area, and mean lake surface temperature. Warmwater species dominated southern lakes, while coolwater and coldwater species had higher abundances in northern lakes. Coolwater species were present in large southern lakes, whereas warmwater species were excluded from northern lakes that had low mean surface temperatures or low degreeâ days. These results suggest that patterns of lake fish assemblages are shaped by differences in climate as well as lakeâ specific differences in surface temperature regimes and in vertical availability of coldwater and coolwater habitats. Because we related fish patterns to readily available landscapeâ level data, our approach can be used to characterize fish assemblages in all lakes across broad geographic extents.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142256/1/tafs0414.pd

Noroviruses Co-opt the Function of Host Proteins VAPA and VAPB for Replication via a Phenylalanine-Phenylalanine-Acidic-Tract-Motif Mimic in Nonstructural Viral Protein NS1/2.

The Norovirus genus contains important human pathogens, but the role of host pathways in norovirus replication is largely unknown. Murine noroviruses provide the opportunity to study norovirus replication in cell culture and in small animals. The human norovirus nonstructural protein NS1/2 interacts with the host protein VAMP-associated protein A (VAPA), but the significance of the NS1/2-VAPA interaction is unexplored. Here we report decreased murine norovirus replication in VAPA- and VAPB-deficient cells. We characterized the role of VAPA in detail. VAPA was required for the efficiency of a step(s) in the viral replication cycle after entry of viral RNA into the cytoplasm but before the synthesis of viral minus-sense RNA. The interaction of VAPA with viral NS1/2 proteins is conserved between murine and human noroviruses. Murine norovirus NS1/2 directly bound the major sperm protein (MSP) domain of VAPA through its NS1 domain. Mutations within NS1 that disrupted interaction with VAPA inhibited viral replication. Structural analysis revealed that the viral NS1 domain contains a mimic of the phenylalanine-phenylalanine-acidic-tract (FFAT) motif that enables host proteins to bind to the VAPA MSP domain. The NS1/2-FFAT mimic region interacted with the VAPA-MSP domain in a manner similar to that seen with bona fide host FFAT motifs. Amino acids in the FFAT mimic region of the NS1 domain that are important for viral replication are highly conserved across murine norovirus strains. Thus, VAPA interaction with a norovirus protein that functionally mimics host FFAT motifs is important for murine norovirus replication.IMPORTANCE Human noroviruses are a leading cause of gastroenteritis worldwide, but host factors involved in norovirus replication are incompletely understood. Murine noroviruses have been studied to define mechanisms of norovirus replication. Here we defined the importance of the interaction between the hitherto poorly studied NS1/2 norovirus protein and the VAPA host protein. The NS1/2-VAPA interaction is conserved between murine and human noroviruses and was important for early steps in murine norovirus replication. Using structure-function analysis, we found that NS1/2 contains a short sequence that molecularly mimics the FFAT motif that is found in multiple host proteins that bind VAPA. This represents to our knowledge the first example of functionally important mimicry of a host FFAT motif by a microbial protein

Trans-Ethnic Mapping of BANK1 Identifies Two Independent SLE-Risk Linkage Groups Enriched for Co-Transcriptional Splicing Marks

BANK1 is a susceptibility gene for several systemic autoimmune diseases in several populations. Using the genome-wide association study (GWAS) data from Europeans (EUR) and African Americans (AA), we performed an extensive fine mapping of ankyrin repeats 1 (BANK1). To increase the SNP density, we used imputation followed by univariate and conditional analysis, combinedwith a haplotypic and expression quantitative trait locus (eQTL) analysis. The data from Europeans showed that the associated region was restricted to a minimal and dependent set of SNPs covering introns two and three, and exon two. In AA, the signal found in the Europeans was split into two independent effects. All of the major risk associated SNPs were eQTLs, and the risks were associated with an increased BANK1 gene expression. Functional annotation analysis revealed the enrichment of repressive B cell epigenomicmarks (EZH2 and H3K27me3) and a strong enrichment of splice junctions. Furthermore, one eQTL located in intron two, rs13106926, was found within the binding site for RUNX3, a transcriptional activator. These results connect the local genome topography, chromatin structure, and the regulatory landscape of BANK1 with co-transcriptional splicing of exon two. Our data defines a minimal set of risk associated eQTLs predicted to be involved in the expression of BANK1 modulated through epigenetic regulation and splicing. These findings allow us to suggest that the increased expression of BANK1 will have an impact on B-cell mediated disease pathways.The work presented in this paper has been supported by the Ministerio de Economía y Competitividad, Spain (SAF2016-78631-P), partly co-financed by FEDER funds of the European Union, the Gustaf den V:e-80-års Fond and the Swedish Association against Rheumatism to M.E.A-R. In addition, this work was financed by the NIH P01 grant P01-AI-083194 to C.D.L., J.B.H., R.K., and M.E.A-R. JBH: NIH grants: R01 AI024717, U01 HG00866, P30 AR070549 and U01 AI130830 and the US Department of Veterans Affairs: I01 BX001834.C.D.L.: Center for Public Health Genomics. R.K.: NIH grant R01-AR33062. J.A.J.: NIH grants U54GM104938, P30AR053483