Now showing items 6796-6815 of 13762

    • Motivation and Engagement during Visually Guided Behavior

      Ortiz, Alexander V; Aziz, David; Hestrin, Shaul; Univ Arizona, Coll Opt Sci (CELL PRESS, 2020-10-20)
      Animal behavior is motivated by internal drives, such as thirst and hunger, generated in hypothalamic neurons that project widely to many brain areas. We find that water-restricted mice maintain stable, high-level contrast sensitivity and brief reaction time while performing a visual task, but then abruptly stop and become disengaged. Mice consume a significant amount of water when freely provided in their home cage immediately after the task, indicating that disengagement does not reflect cessation of thirst. Neuronal responses of V1 neurons are reduced in the disengaged state, but pupil diameter does not decrease, suggesting that animals' reduced level of arousal does not drive the transition to disengagement. Our findings indicate that satiation level alone does not have an instructive role in visually guided behavior and suggest that animals' behavior is governed by cost-benefit analysis that can override thirst signals.
    • Motivations and methods for the analysis of multi-modality x-ray systems for explosives detection

      Carpenter, Joshua; Ding, Yijun; Hurlock, Ava; Coccarelli, David; Gregory, Christopher; Diallo, Souleymane O.; Ashok, Amit; Gehm, Michael E.; Greenberg, Joel A.; Univ Arizona (SPIE-INT SOC OPTICAL ENGINEERING, 2019-05-14)
      Transmission-based imaging and X-ray diffraction-based material analysis have largely developed independently. However, for a variety of applications ranging from in-vivo soft tissue analysis to concealed explosives detection, it is necessary to realize high-fidelity, spatially-resolved material discrimination. We therefore seek to understand to what degree transmission and X-ray diffraction (XRD) complement one another and can be implemented practically, particularly in the case of explosives detection in aviation security. Using a combination of simulated and experimental data, we identify the relative value of the X-ray signatures available to transmission and XRD measurements, and explore how the measurement fidelity can impact these results.
    • A motor unit-based model of muscle fatigue

      Potvin, Jim R.; Fuglevand, Andrew J.; Univ Arizona, Coll Med, Dept Physiol (PUBLIC LIBRARY SCIENCE, 2017-06-02)
      Muscle fatigue is a temporary decline in the force and power capacity of skeletal muscle resulting from muscle activity. Because control of muscle is realized at the level of the motor unit (MU), it seems important to consider the physiological properties of motor units when attempting to understand and predict muscle fatigue. Therefore, we developed a phenomenological model of motor unit fatigue as a tractable means to predict muscle fatigue for a variety of tasks and to illustrate the individual contractile responses of MUs whose collective action determines the trajectory of changes in muscle force capacity during prolonged activity. An existing MU population model was used to simulate MU firing rates and isometric muscle forces and, to that model, we added fatigue-related changes in MU force, contraction time, and firing rate associated with sustained voluntary contractions. The model accurately estimated endurance times for sustained isometric contractions across a wide range of target levels. In addition, simulations were run for situations that have little experimental precedent to demonstrate the potential utility of the model to predict motor unit fatigue for more complicated, real-worldapplications. Moreover the model provided insight, into the complex orchestration of MU force contributions during fatigue, that would be unattainable with current experimental approaches
    • Mottled Protoplanetary Disk Ionization by Magnetically Channeled T Tauri Star Energetic Particles

      Fraschetti, Federico; Drake, J. J.; Cohen, O.; Garraffo, C.; Univ Arizona, Dept Astron (IOP PUBLISHING LTD, 2018-01-30)
      The evolution of protoplanetary disks is believed to be driven largely by angular momentum transport resulting from magnetized disk winds and turbulent viscosity. The ionization of the disk that is essential for these processes has been thought to be due to host star coronal X-rays but could also arise from energetic particles produced by coronal flares, or traveling shock waves, and advected by the stellar wind. We have performed test-particle numerical simulations of energetic protons propagating into a realistic T. Tauri stellar wind, including a superposed small-scale magnetostatic turbulence. The isotropic (Kolmogorov power spectrum) turbulent component is synthesized along the individual particle trajectories. We have investigated the energy range [0.1-10] GeV, consistent with expectations from Chandra X-ray observations of large flares on T. Tauri stars and recent indications by the Herschel Space Observatory of a significant contribution of energetic particles to the disk ionization of young stars. In contrast with a previous theoretical study finding a dominance of energetic particles over X-rays in the ionization throughout the disk, we find that the disk ionization is likely dominated by X-rays over much of its area, except within narrow regions where particles are channeled onto the disk by the strongly tangled and turbulent magnetic field. The radial thickness of such regions is 5 stellar radii close to the star and broadens with increasing radial distance. This likely continues out to large distances from the star (10 au or greater), where particles can be copiously advected and diffused by the turbulent wind.
    • Mountain‐Block Recharge: A Review of Current Understanding

      Markovich, Katherine H.; Manning, Andrew H.; Condon, Laura E.; McIntosh, Jennifer C.; Univ Arizona, Dept Hydrol & Atmospher Sci (American Geophysical Union (AGU), 2019-11-11)
      Mountain‐block recharge (MBR) is the subsurface inflow of groundwater to lowland aquifers from adjacent mountains. MBR can be a major component of recharge but remains difficult to characterize and quantify due to limited hydrogeologic, climatic, and other data in the mountain block and at the mountain front. The number of MBR‐related studies has increased dramatically in the 15 years since the last review of the topic was conducted by Wilson and Guan (2004), generating important advancements. We review this recent body of literature, summarize current understanding of factors controlling MBR, and provide recommendations for future research priorities. Prior to 2004, most MBR studies were performed in the southwestern United States. Since then, numerous studies have detected and quantified MBR in basins around the world, typically estimating MBR to be 5–50% of basin‐fill aquifer recharge. Theoretical studies using generic numerical modeling domains have revealed fundamental hydrogeologic and topographic controls on the amount of MBR and where it originates within the mountain block. Several mountain‐focused hydrogeologic studies have confirmed the widespread existence of mountain bedrock aquifers hosting considerable groundwater flow and, in some cases, identified the occurrence of interbasin flow leaving headwater catchments in the subsurface—both of which are required for MBR to occur. Future MBR research should focus on the collection of high‐priority data (e.g., subsurface data near the mountain front and within the mountain block) and the development of sophisticated coupled models calibrated to multiple data types to best constrain MBR and predict how it may change in response to climate warming.
    • A Mountain‐Front Recharge Component Characterization Approach Combining Groundwater Age Distributions, Noble Gas Thermometry, and Fluid and Energy Transport Modeling

      Markovich, Katherine H.; Condon, Laura E.; Carroll, Kenneth C.; Purtschert, Roland; McIntosh, Jennifer C.; Department of Hydrology and Atmospheric Sciences, University of Arizona (Blackwell Publishing Ltd, 2020-12-11)
      Mountain-front recharge (MFR), or all inflow to a basin-fill aquifer with its source in the mountain block, is an important component of recharge to basin-fill aquifer systems. Distinguishing and quantifying the surface from subsurface components of MFR is necessary for water resource planning and management, particularly as climate change may impact these components in distinct ways. This study tests the hypothesis that MFR components can be distinguished in long-screened, basin-fill production wells by (1) groundwater age and (2) the median elevation of recharge. We developed an MFR characterization approach by combining age distributions in six wells using tritium, krypton-85, argon-39, and radiocarbon, and median recharge elevations from noble gas thermometry combined with numerical experiments to determine recharge temperature lapse rates using flow and energy transport modeling. We found that groundwater age distributions provided valuable information for characterizing the dominant flow system behavior captured by the basin-fill production wells. Tracers indicated the presence of old (i.e., no detectable tritium) water in a well completed in weathered bedrock located close to the mountain front. Two production wells exhibited age distributions of binary mixing between modern and a small fraction of old water, whereas the remaining wells captured predominantly modern flow paths. Noble gas thermometry provided important complementary information to the age distributions; however, assuming constant recharge temperature lapse rates produced improbable recharge elevations. Numerical experiments suggest that surface MFR, if derived from snowmelt, can locally suppress water table temperatures in the basin-fill aquifer, with implications for recharge elevations estimated from noble gas thermometry. © 2020. American Geophysical Union. All Rights Reserved.
    • Movement of Sediment Through a Burned Landscape: Sediment Volume Observations and Model Comparisons in the San Gabriel Mountains, California, USA

      Rengers, F.K.; McGuire, L.A.; Kean, J.W.; Staley, D.M.; Dobre, M.; Robichaud, P.R.; Swetnam, T.; University of Arizona (John Wiley and Sons Inc, 2021)
      Post-wildfire changes to hydrologic and geomorphic systems can lead to widespread sediment redistribution. Understanding how sediment moves through a watershed is crucial for assessing hazards, developing debris flow inundation models, engineering sediment retention solutions, and quantifying the role that disturbances play in landscape evolution. In this study, we used terrestrial and airborne lidar to measure sediment redistribution in the 2016 Fish Fire, in the San Gabriel Mountains in southern California, USA. The lidar areas are in two adjacent watersheds, at spatial scales of 900 m2 to 4 km2, respectively. Terrestrial lidar data were acquired prior to rainfall, and two subsequent surveys show erosional change after rainstorms. Two airborne lidar flights occurred (1) 7 months before, and (2) 14 months after the fire ignition, capturing the erosional effects after rainfall. We found hillslope erosion dominated the overall sediment budget in the first rainy season after wildfire. Only 7% of the total erosion came from the active channel bed and channel banks, and the remaining 93% of eroded sediment was derived from hillslopes. Within the channelized portion of the watershed erosion/deposition could be generally described with topographic metrics used in a stream power equation. Observed sediment volumes were compared with four empirical models and one process-based model. We found that the best predictions of sediment volume were obtained from an empirical model developed in the same physiographic region. Moreover, this study showed that post-wildfire erosion rates in the San Gabriel Mountains attain the same magnitude as millennial time scale bedrock erosion rates. © 2021. The Authors. This article has been contributed to by US Government employees and their work is in the public domain in the USA.
    • Movers and shakers: Bumble bee foraging behavior shapes the dispersal of microbes among and within flowers

      Russell, Avery L.; Rebolleda‐Gómez, María; Shaible, Tierney Marie; Ashman, Tia‐Lynn; Univ Arizona, Entomol & Insect Sci Grad Interdisciplinary Progr (Wiley, 2019-05-17)
      Dispersal is central to the ecology and evolution of spatially structured communities. While flower microbial communities are spatially structured among floral organs, how dispersal vectors distribute microbes among floral organs is unknown. Pollinators are recognized as key microbial vectors, but effects of their different foraging behaviors on transfer dynamics among flowers or different floral organs are not known. We asked how foraging behaviors of a model pollinator (Bombus impatiens) affect acquisition and dispersal of microbes among flower organs. We used monkeyflowers (Mimulus guttatus) to examine dispersal within a natural context and artificial flowers to test how common bee foraging behaviors (nectaring, buzzing, or scrabbling) shaped dispersal of a green fluorescent protein‐labeled bacteria, Pseudomonas fluorescens. Bees acquired 1% of a flower's microbes and dispersed 31% of acquired microbes to the next flower. All bees acquired microbes, and 85% and 76% of bees dispersed microbes to live and artificial flowers, respectively. Microbes acquired from the corolla were mainly deposited on the corolla, followed by the stamens, and least on the nectary/pistil. Bee foraging behavior affected acquisition, with scrabbling for pollen resulting in 23% more microbes acquired than nectaring, and with buzzing for pollen resulting in a 79% slower rate of microbial acquisition relative to scrabbling. Bee foraging behavior also affected deposition but depended on the floral organ: Scrabbling and buzzing for pollen led to greater deposition than nectaring for corolla and stamen but not nectary. Our results have implications for transmission of beneficial and pathogenic microbes among plants and pollinators, and thus the ecology and evolution of floral microbial communities.
    • Moving Beyond Readability Metrics for Health-Related Text Simplification

      Kauchak, David; Leroy, Gondy; Univ Arizona, Eller Coll Management, Management Informat Syst (IEEE COMPUTER SOC, 2016)
      Limited health literacy is a barrier to understanding health information. Simplifying text can reduce this barrier and possibly other known disparities in health. Unfortunately, few tools exist to simplify text with demonstrated impact on comprehension. By leveraging modern data sources integrated with natural language processing algorithms, we are developing the first semi-automated text simplification tool. We present two main contributions. First, we introduce our evidence-based development strategy for designing effective text simplification software and summarize initial, promising results. Second, we present a new study examining existing readability formulas, which are the most commonly used tools for text simplification in healthcare. We compare syllable count, the proxy for word difficulty used by most readability formulas, with our new metric 'term familiarity' and find that syllable count measures how difficult words 'appear' to be, but not their actual difficulty. In contrast, term familiarity can be used to measure actual difficulty.
    • MP470, a novel receptor tyrosine kinase inhibitor, in combination with Erlotinib inhibits the HER family/PI3K/Akt pathway and tumor growth in prostate cancer

      Qi, Wenqing; Cooke, Larry; Stejskal, Amy; Riley, Christopher; Croce, Kimiko; Saldanha, Jose; Bearss, David; Mahadevan, Daruka; Arizona Cancer Center, the University of Arizona, Tucson, AZ 85724, USA; National Institute for Medical Research, Mill Hill, London, UK; et al. (BioMed Central, 2009)
      BACKGROUND:Prostate cancer is a common disease in men and at present there is no effective therapy available due to its recurrence despite androgen deprivation therapy. The epidermal growth factor receptor family (EGFR/HER1, HER2/neu and HER3)/PI3K/Akt signaling axis has been implicated in prostate cancer development and progression. However, Erlotinib, an EGFR tyrosine kinase inhibitor, has less effect on proliferation and apoptosis in prostate cancer cell lines. In this study, we evaluate whether MP470, a novel receptor tyrosine kinase inhibitor alone or in combination with Erlotinib has inhibitory effect on prostate cancer in vitro and in vivo.METHODS:The efficacy of MP470 or MP470 plus Erlotinib was evaluated in vitro using three prostate cancer cell lines by MTS and apoptosis assays. The molecular mechanism study was carried out by phosphorylation antibody array, immunoblotting and immunohistochemistry. A LNCaP mouse xenograft model was also used to determine the tumor growth inhibition by MP470, Erlotinib or the combination treatments.RESULTS:MP470 exhibits low muM IC50 in prostate cancer cell lines. Additive effects on both cytotoxicity and induction of apoptosis were observed when LNCaP were treated with MP470 in combination with Erlotinib. This combination treatment completely inhibited phosphorylation of the HER family members (HER1, 2, 3), binding of PI3K regulatory unit p85 to HER3 and downstream Akt activity even after androgen depletion. Furthermore, in a LNCaP mouse xenograft model, the MP470-Erlotinib combination produced 30-65% dose-dependent tumor growth inhibition (TGI).CONCLUSION:We propose that MP470-Erlotinib targets the HER family/PI3K/Akt pathway and may represent a novel therapeutic strategy for prostate cancer.
    • MR Imaging Biomarkers to Monitor Early Response to Hypoxia-Activated Prodrug TH-302 in Pancreatic Cancer Xenografts

      Zhang, Xiaomeng; Wojtkowiak, Jonathan W.; Martinez, Gary V.; Cornnell, Heather H.; Hart, Charles P.; Baker, Amanda F.; Gillies, Robert; Univ Arizona, Arizona Canc Ctr (Public Library of Science, 2016-05-26)
      TH-302 is a hypoxia-activated prodrug known to activate selectively under the hypoxic conditions commonly found in solid tumors. It is currently being evaluated in clinical trials, including two trials in Pancreatic Ductal Adenocarcinomas (PDAC). The current study was undertaken to evaluate imaging biomarkers for prediction and response monitoring of TH-302 efficacy in xenograft models of PDAC. Dynamic contrast-enhanced (DCE) and diffusion weighted (DW) magnetic resonance imaging (MRI) were used to monitor acute effects on tumor vasculature and cellularity, respectively. Three human PDAC xenografts with known differential responses to TH-302 were imaged prior to, and at 24 h and 48 hours following a single dose of TH-302 or vehicle to determine if imaging changes presaged changes in tumor volumes. DW-MRI was performed at five b-values to generate apparent diffusion coefficient of water (ADC) maps. For DCE-MRI, a standard clinically available contrast reagent, Gd-DTPA, was used to determine blood flow into the tumor region of interest. TH-302 induced a dramatic decrease in the DCE transfer constant (K-trans) within 48 hours after treatment in the sensitive tumors, Hs766t and Mia PaCa-2, whereas TH-302 had no effect on the perfusion behavior of resistant SU. 86.86 tumors. Tumor cellularity, estimated from ADC, was significantly increased 24 and 48 hours after treatment in Hs766t, but was not observed in the Mia PaCa-2 and SU. 86.86 groups. Notably, growth inhibition of Hs766t was observed immediately (day 3) following initiation of treatment, but was not observed in Mia-PaCa-2 tumors until 8 days after initiation of treatment. Based on these preclinical findings, DCE-MRI measures of vascular perfusion dynamics and ADC measures of cell density are suggested as potential TH-302 response biomarkers in clinical trials.
    • Mrk 1239: A Type-2 Counterpart of Narrow-line Seyfert-1?

      Pan, X.; Zhou, H.; Yang, C.; Sun, L.; Smith, P.S.; Ji, T.; Jiang, N.; Jiang, P.; Liu, W.; Lu, H.; et al. (IOP Publishing Ltd, 2021)
      We present new spectrophotometric and spectropolarimetric observations of Mrk 1239, one of the 8 prototypes that defines type-1 narrow-line Seyfert galaxies (NLS1s). Unlike the other typical NLS1s though, a high degree of polarization (P ∼ 5.6%) and red optical-IR (g-W 4 = 12.35) colors suggest that Mrk 1239 is more similar to type-2 active galactic nuclei like NGC 1068. Detailed analysis of spectral energy distribution in the UV-optical-IR yields two components from the nucleus: a direct and transmitted component that is heavily obscured (E B-V ≈ 1.6), and another indirect and scattered one with mild extinction (E B-V ∼ 0.5). Such a two-light-paths scenario is also found in previous reports based on the X-ray data. Comparison of emission lines and the detection of He i∗λ10830 BAL at [-3000, -1000] km s-1 indicates that the obscuring clouds are at physical scale between the sublimation radius and that of the narrow emission line regions. The potential existence of powerful outflows is found as both the obscurer and scatterer are outflowing. Similar to many other type-2s, jet-like structure in the radio band is found in Mrk 1239, perpendicular to the polarization angle, suggesting polar scattering. We argue that Mrk 1239 is very probably a type-2 counterpart of NLS1s. The identification of 1 out of 8 prototype NLS1s as a type-2 counterpart implies that there can be a substantial amount of analogs of Mrk 1239 misidentified as type-1s in the optical band. Properties of these misidentified objects are going to be explored in our future works. © 2021. The American Astronomical Society. All rights reserved..
    • MSSM at future Higgs factories

      Li, H.; Song, H.; Su, S.; Su, W.; Yang, J.M.; Department of Physics, University of Arizona (IOP Publishing Ltd, 2021)
      In this work, we study the implications of Higgs precision measurements at future Higgs factories for the MSSM parameter space, focusing on the dominant stop sector contributions. We perform a multi-variable fit to both the signal strength for various Higgs decay channels at Higgs factories and the Higgs mass. The χ 2 fit results show sensitivity to mA, tan β, stop mass parameter m SUSY, and the stop left-right mixing parameter Xt. We also study the impact of the Higgs mass prediction on the MSSM and compare the sensitivities of different Higgs factories. © 2021Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Sciences and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.
    • MTGO: PPI Network Analysis Via Topological and Functional Module Identification

      Vella, Danila; Marini, Simone; Vitali, Francesca; Di Silvestre, Dario; Mauri, Giancarlo; Bellazzi, Riccardo; Univ Arizona Hlth Sci, Inst Ctr Biomed Informat & Biostat BIO5 (NATURE PUBLISHING GROUP, 2018-04-03)
      Protein-protein interaction (PPI) networks are viable tools to understand cell functions, disease machinery, and drug design/repositioning. Interpreting a PPI, however, it is a particularly challenging task because of network complexity. Several algorithms have been proposed for an automatic PPI interpretation, at first by solely considering the network topology, and later by integrating Gene Ontology (GO) terms as node similarity attributes. Here we present MTGO - Module detection via Topological information and GO knowledge, a novel functional module identification approach. MTGO let emerge the bimolecular machinery underpinning PPI networks by leveraging on both biological knowledge and topological properties. In particular, it directly exploits GO terms during the module assembling process, and labels each module with its best fit GO term, easing its functional interpretation. MTGO shows largely better results than other state of the art algorithms (including recent GO-based ones) when searching for small or sparse functional modules, while providing comparable or better results all other cases. MTGO correctly identifies molecular complexes and literature-consistent processes in an experimentally derived PPI network of Myocardial infarction. A software version of MTGO is available freely for non-commercial purposes at
    • Mucinous adenocarcinoma of the endometrium with metastasis to the clitoral glans after pelvic exenteration for radiation resistant vaginal cuff recurrence

      Mogor, Odinaka; Hargrave, Emily; Rush, Demarreta; Hatch, Kenneth; Univ Arizona, Dept Pathol (ELSEVIER SCIENCE INC, 2019-02-01)
      Mucinous adenocarcinoma of the endometrium (MACE) is a rare subtype of endometrial adenocarcinoma that often presents a significant diagnostic challenge due to its variation from the conventional morphologic appearance of endometrioid epithelium. This case report is of a woman who has survived 4 years after pelvic exenteration and subsequent vulvectomy for recurrent MACE.
    • Mucosa-Associated Lymphoid Tissue Lymphoma of the Larynx

      Rizvi, Omar; Nielsen, Tyson; Bearelly, Shethal; Univ Arizona, Dept Otolaryngol (HINDAWI LTD, 2020-08)
      Background. Mucosa-associated lymphoid tissue (MALT) lymphomas are a subtype of non-Hodgkin lymphoma stemming from marginal zone B-cells. In this case report, we present two patients with an extremely rare localization of MALT lymphoma to the larynx.Methods. Case 1 is of a 78-year-old male presenting with a six-month history of progressive hoarseness with a past medical history significant for marginal zone lymphoma of the right orbit. Diagnosis was confirmed with a biopsy for extranodal marginal zone B-cell lymphoma of MALT type. An FDG-PET scan was done but did not show any sign of FDG avid malignancy, including at the primary site. Case 2 is a 60-year-old female presenting with one year of worsening throat discomfort, intermittent cough, and dyspnea with exertion. Pathology confirmed a diagnosis of extranodal marginal zone B-cell lymphoma of MALT type.Results. Case 1 was treated with low-dose radiation at 4 Gy delivered over two fractions of 2 Gy each. Upon completion of radiation treatment, he reported a resolution of his hoarseness and normalization of his voice. A four-month follow-up in May 2018 with flexible nasolaryngoscopy revealed a normal exam with fully mobile vocal folds bilaterally and no evidence of left false vocal fold submucosal mass. At seven months following treatment, the patient died unexpectedly of unknown causes. Case 2 was treated with radiation at 30 Gy in 15 fractions over the course of one month. Following completion of radiation therapy, she had improvement of her sore throat, nausea, dysphagia, dysgeusia, and dry mouth. At 21-month follow-up, she had no evidence of disease.Conclusion. This case report demonstrates that MALT lymphoma can present with much more benign and subtle symptoms. This highlights the importance of clinicians to keep broad differentials and consider MALT lymphomas in the setting of laryngeal masses.
    • Mucus plugs in patients with asthma linked to eosinophilia and airflow obstruction.

      Dunican, Eleanor M; Elicker, Brett M; Gierada, David S; Nagle, Scott K; Schiebler, Mark L; Newell, John D; Raymond, Wilfred W; Lachowicz-Scroggins, Marrah E; Di Maio, Selena; Hoffman, Eric A; et al. (AMER SOC CLINICAL INVESTIGATION INC, 2018-03-01)
      The link between mucus plugs and airflow obstruction has not been established in chronic severe asthma, and the role of eosinophils and their products in mucus plug formation is unknown. In clinical studies, we developed and applied a bronchopulmonary segment-based scoring system to quantify mucus plugs on multidetector computed tomography (MDCT) lung scans from 146 subjects with asthma and 22 controls, and analyzed relationships among mucus plug scores, forced expiratory volume in 1 second (FEV1), and airway eosinophils. Additionally, we used airway mucus gel models to explore whether oxidants generated by eosinophil peroxidase (EPO) oxidize cysteine thiol groups to promote mucus plug formation. Mucus plugs occurred in at least 1 of 20 lung segments in 58% of subjects with asthma and in only 4.5% of controls, and the plugs in subjects with asthma persisted in the same segment for years. A high mucus score (plugs in ≥ 4 segments) occurred in 67% of subjects with asthma with FEV1 of less than 60% of predicted volume, 19% with FEV1 of 60%-80%, and 6% with FEV1 greater than 80% (P < 0.001) and was associated with marked increases in sputum eosinophils and EPO. EPO catalyzed oxidation of thiocyanate and bromide by H2O2 to generate oxidants that crosslink cysteine thiol groups and stiffen thiolated hydrogels. Mucus plugs are a plausible mechanism of chronic airflow obstruction in severe asthma, and EPO-generated oxidants may mediate mucus plug formation. We propose an approach for quantifying airway mucus plugging using MDCT lung scans and suggest that treating mucus plugs may improve airflow in chronic severe asthma.
    • Mudflow Modeling in the Copiapo Basin, Chile

      Valdes-Pineda, Rodrigo; Valdes, Juan B.; Garcia-Chevesich, Pablo; Univ Arizona, Dept Hydrol & Atmospher Sci (UNIV POLITECNICA VALENCIA, 2017-04-28)
      Extreme precipitation events that occurred between March 24 and March 26 of 2015 in the region of the Atacama Desert (26-29 degrees S) left around 30000 victims, being one of the biggest events over the past 50 years, with total a cost of reconstruction of about 1.5 billion dollars. The mudflows which increased during the flashflood inundated much of the city of Copiapo and Tierra Amarilla. This manuscript aims to model the mudflow of March 2015 in the Rio Copiapo, specifically in the towns of Copiapo and Tierra Amarilla. The modeling process is performed using the Rapid Mass Movement Simulation Model (RAMMS) that allows modeling the dynamics of the mudflow in two dimensions, only using the topographic features of the modeling domain. Calibration of the model was carried out successfully using data from inundation heights captured around the city after the 2015 event. A detailed analysis of the hydrometeorological event is carried out using satellite images obtained from Multi-satellite Precipitation Analysis (TMPA), and pluviometric and hydrographic data available in the Copiapo River basin. The simulation of the flood is reproduced with maps of inundation heights associated with two modeling scenarios. The maximum flood heights are ultimately used for developing risk maps at both sites. According to our results, the RAMMS model is an appropriate tool for modeling mudflow and mapping flood risk to improve hydrological risk management in arid and semiarid basins of Chile.
    • Mueller matrix maps of dichroic filters reveal polarization aberrations

      Heath, James; Kupinski, Meredith; Douglas, Ewan; Hart, Kira; Breckinridge, James; Wyant College of Optical Science, University of Arizona; Steward Observatory, University of Arizona (SPIE, 2020-12-22)
      Dichroic filters are used by instrument designers to split a field of view into different optical paths for simultaneous measurement of different spectral bands. Quantifying the polarization aberrations of a dichroic is relevant for predicting the incident polarization states downstream, which could affect the performance of diffraction limited systems. One important application is the fore-optics of exoplanet imaging coronagraphs. In this work, the polarization properties of the Edmund #69-205 650 nm roll-off dichroic are measured using a rotating retarder Mueller matrix imaging polarimeter. The polarization properties of this commercial dichroic are compared at normal and 45° angle of incidence. The normal incidence measurements verify the instrument calibration since no polarization aberrations were observed. Transmission measurements at 680 nm and 45° yield a 2.9 rad magnitude of retardance and 0.95 diattenuation. Effectively, at 630 nm the dichroic is a λ/4 waveplate with a horizontal fast-axis.
    • Multi-angle VECSEL cavities for dispersion control and multi-color operation

      Baker, Caleb; Scheller, Maik; Laurain, Alexandre; Yang, Hwang-Jye; Ruiz Perez, Antje; Stolz, Wolfgang; Addamane, Sadhvikas J.; Balakrishnan, Ganesh; Jones, R. Jason; Moloney, Jerome V.; et al. (SPIE-INT SOC OPTICAL ENGINEERING, 2017-02-22)
      We present a novel Vertical External Cavity Surface Emitting Laser (VECSEL) cavity design which makes use of multiple interactions with the gain region under different angles of incidence in a single round trip. This design allows for optimization of the net, round-trip Group Delay Dispersion (GDD) by shifting the GDD of the gain via cavity fold angle while still maintaining the high gain of resonant structures. The effectiveness of this scheme is demonstrated with femtosecond-regime pulses from a resonant structure and record pulse energies for the VECSEL gain medium. In addition, we show that the interference pattern of the intracavity mode within the active region, resulting from the double-angle multifold, is advantageous for operating the laser in CW on multiple wavelengths simultaneously. Power, noise, and mode competition characterization is presented.