Browsing by Author "Lu, Y"

Now showing 1 - 6 of 6
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    Common Genetic Variants near the Brittle Cornea Syndrome Locus ZNF469 Influence the Blinding Disease Risk Factor Central Corneal Thickness
    (PLoS Genetics, 2010-05-13) Lu, Y; Dimasi, DP; Hysi, PG; Hewitt, AW; Burdon, KP; Toh, T; Ruddle, JB; Li, YJ; Mitchell, P; Healey, PR; Montgomery, GW; Hansell, N; Spector, TD; Martin, NG; Young, TL; Hammond, CJ; Macgregor, S; Craig, JE; Mackey, DA
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    Evidence that SOX2 overexpression is oncogenic in the lung.
    (PLoS One, 2010-06-10) Lu, Y; Futtner, C; Rock, JR; Xu, X; Whitworth, W; Hogan, BL; Onaitis, MW
    BACKGROUND: SOX2 (Sry-box 2) is required to maintain a variety of stem cells, is overexpressed in some solid tumors, and is expressed in epithelial cells of the lung. METHODOLOGY/PRINCIPAL FINDINGS: We show that SOX2 is overexpressed in human squamous cell lung tumors and some adenocarcinomas. We have generated mouse models in which Sox2 is upregulated in epithelial cells of the lung during development and in the adult. In both cases, overexpression leads to extensive hyperplasia. In the terminal bronchioles, a trachea-like pseudostratified epithelium develops with p63-positive cells underlying columnar cells. Over 12-34 weeks, about half of the mice expressing the highest levels of Sox2 develop carcinoma. These tumors resemble adenocarcinoma but express the squamous marker, Trp63 (p63). CONCLUSIONS: These findings demonstrate that Sox2 overexpression both induces a proximal phenotype in the distal airways/alveoli and leads to cancer.
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    Geometric ergodicity of Langevin dynamics with Coulomb interactions
    Lu, Y; Mattingly, JC
    This paper is concerned with the long time behavior of Langevin dynamics of {\em Coulomb gases} in $\mathbf{R}^d$ with $d\geq 2$, that is a second order system of Brownian particles driven by an external force and a pairwise repulsive Coulomb force. We prove that the system converges exponentially to the unique Boltzmann-Gibbs invariant measure under a weighted total variation distance. The proof relies on a novel construction of Lyapunov function for the Coulomb system.
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    No-Holdback allocation rules for continuous-time assemble-to-order systems
    (Operations Research, 2010-05-01) Lu, Y; Song, JS; Zhao, Y
    This paper analyzes a class of common-component allocation rules, termed no-holdback (NHB) rules, in continuous-review assemble-to-order (ATO) systems with positive lead times. The inventory of each component is replenished following an independent base-stock policy. In contrast to the usually assumed first-come-first-served (FCFS) component allocation rule in the literature, an NHB rule allocates a component to a product demand only if it will yield immediate fulfillment of that demand. We identify metrics as well as cost and product structures under which NHB rules outperform all other component allocation rules. For systems with certain product structures, we obtain key performance expressions and compare them to those under FCFS. For general product structures, we present performance bounds and approximations. Finally, we discuss the applicability of these results to more general ATO systems. © 2010 INFORMS.
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    Sensorimotor learning during a marksmanship task in immersive virtual reality
    (Frontiers in Psychology, 2018-01-15) Appelbaum, Lawrence Gregory; Clements, Jillian; Khanna, Rajan; Kopper, Regis; Lu, Y; Potter, Nicholas; Rao, Hrishikesh; Sommer, Marc A; Zielinski, David
    Sensorimotor learning refers to improvements that occur through practice in the performance of sensory-guided motor behaviors. Leveraging novel technical capabilities of an immersive virtual environment, we probed the component kinematic processes that mediate sensorimotor learning. Twenty naïve subjects performed a simulated marksmanship task modeled after Olympic Trap Shooting standards. We measured movement kinematics and shooting performance as participants practiced 350 trials while receiving trial-by-trial feedback about shooting success. Spatiotemporal analysis of motion tracking elucidated the ballistic and refinement phases of hand movements. We found systematic changes in movement kinematics that accompanied improvements in shot accuracy during training, though reaction and response times did not change over blocks. In particular, we observed longer, slower, and more precise ballistic movements that replaced effort spent on corrections and refinement. Collectively, these results leverage developments in immersive virtual reality technology to quantify and compare the kinematics of movement during early learning of full body sensorimotor orienting.
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    The continuous analysis of nitrate and ammonium in aerosols by the steam jet aerosol collector (SJAC): extension and validation of the methodology
    (ATMOSPHERIC ENVIRONMENT, 2001) Slanina, J; ten Brink, HM; Otjes, RP; Even, A; Jongejan, P; Khlystov, A; Waijers-Ijpelaan, A; Hu, M; Lu, Y
    Classical methodology based on the application of filters for sampling, followed by extraction and analysis, introduces severe artifacts for semi-volatile compounds like ammonium nitrate. These filter methods do not meet the requirements for the assessment of the impact of aerosols on acidification, air quality and especially on the radiative balance, in terms of required speed, detection limits and selectivity. These artifacts are avoided by using a steam jet aerosol collector sampler, based on scavenging of aerosols by droplet formation, in combination with on-line analytical techniques such as ion-chromatography for nitrate and membrane separation followed by conductivity detection for ammonium. The SJAC sampler combines very low blanks with high efficiency of collection of particles. The ammonium detector and the IC system, based on 1-point internal standard calibration in combination with correction for curved calibration graphs, enables detection of ammonium and nitrate at background conditions, the detection limit is about 0.02 mug m(-3) of ammonium and nitrate. Accuracy is, depending on ambient concentration, in the order of 5-10\% relative, at a range of 0.05-50 mug m(-3). The: time resolution is 15-120min, depending on required detection limit, and is short enough for continuously monitoring the chemical composition of aerosols. Quality assurance and quality control experiments and intercomparison experiments with classical filter methods, thermo-denuder systems, denuder difference methods and other continuous monitoring techniques have shown that the results are reliable. The instrument has successfully been employed in field campaigns in Europe and the US. (C) 2001 Elsevier Science Ltd. All rights reserved.