688 research outputs found

    Determination of Anaerobic Threshold by Heart Rate or Heart Rate Variability using Discontinuous Cycle Ergometry

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    International Journal of Exercise Science 7(1) : 45-53, 2014. The purpose was to determine if heart rate (HR) and heart rate variability (HRV) responses would reflect anaerobic threshold (AT) using a discontinuous, incremental, cycle test. AT was determined by ventilatory threshold (VT). Cyclists (30.6±5.9y; 7 males, 8 females) completed a discontinuous cycle test consisting of 7 stages (6 min each with 3 min of rest between). Three stages were performed at power outputs (W) below those corresponding to a previously established AT, one at W corresponding to AT, and 3 at W above those corresponding to AT. The W at the intersection of the trend lines was considered each metric’s “threshold”. The averaged stage data for Ve, HR, and time- and frequency-domain HRV metrics were plotted versus W. The W at the “threshold” for the metrics of interest were compared using correlation analysis and paired-sample t-test. In all, several heart rate-related parameters accurately reflected AT with significant correlations (p≤0.05) were observed between AT W and HR, mean RR interval (MRR), low and high frequency spectral energy (LF and HR, respectively), high frequency peak (fHF), and HFxfHF metrics’ threshold W (i.e., MRRTW, etc.). Differences in HR or HRV metric threshold W and AT for all subjects were less than 14 W. The steady state data from discontinuous protocols may allow for a true indication of steady-state physiologic stress responses and corresponding W at AT, compared to continuous protocols using 1-2 min exercise stages

    Total Synthesis of the Bovine Pancreatic Trypsin Inhibitor (BPTI) and the Protein Diastereomer [Gly37D-Ala]BPTI using Boc Chemistry Solid Phase Peptide Synthesis

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    Bovine pancreatic trypsin inhibitor (BPTI) is a well‐studied model for investigation of protein folding and stability. Here, we report the synthesis and characterization of wild‐type BPTI and a diastereomeric protein analogue [Gly37D‐Ala]BPTI. Each 58‐residue polypeptide chain was made by native chemical ligation of two peptide segments, BPTI[1‐29]‐αthioester and the appropriate version of the Cys30‐58 BPTI peptide segment. Boc chemistry in situ neutralization solid phase synthesis was used to prepare the peptide segment reactants. The resulting full‐length polypeptide chains were folded in a cysteine/cystine redox buffer to give synthetic protein molecules containing three disulfide bonds. The diastereomeric analogue [Gly37D‐Ala]BPTI folded as efficiently as the native protein. Synthetic proteins were characterized by analytical LCMS and by natural‐abundance 1H‐15N HSQC NMR fingerprinting. These results illustrate the power of Boc chemistry peptide synthesis and its utility for the total chemical synthesis of protein molecules

    Using an epiphytic moss to identify previously unknown sources of atmospheric cadmium pollution

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    Urban networks of air-quality monitors are often too widely spaced to identify sources of air pollutants, especially if they do not disperse far from emission sources. The objectives of this study were to test the use of moss bioindicators to develop a fine-scale map of atmospherically-derived cadmium and to identify the sources of cadmium in a complex urban setting.We collected 346 samples of the moss Orthotrichum lyellii from deciduous trees in December, 2013 using a modified randomized grid-based sampling strategy across Portland, Oregon.We estimated a spatial linear model of moss cadmium levels and predicted cadmium on a 50 m grid across the city. Cadmium levels in moss were positively correlated with proximity to two stained-glass manufacturers, proximity to the Oregon– Washington border, and percent industrial land in a 500 m buffer, and negatively correlated with percent residential land in a 500 m buffer. The maps showed very high concentrations of cadmium around the two stained-glass manufacturers, neither of which were known to environmental regulators as cadmium emitters. In addition, in response to our findings, the Oregon Department of Environmental Quality placed an instrumental monitor 120 m from the larger stained-glass manufacturer in October, 2015. The monthly average atmospheric cadmium concentration was 29.4 ng/m3,which is 49 times higher than Oregon\u27s benchmark of 0.6 ng/m3, and high enough to pose a health risk from even short-term exposure. Both stained-glass manufacturers voluntarily stopped using cadmium after the monitoring results were made public, and the monthly average cadmium levels precipitously dropped to 1.1 ng/m3 for stained-glass manufacturer #1 and 0.67 ng/m3 for stained-glass manufacturer #2

    Using an epiphytic moss to identify previously unknown sources of atmospheric cadmium pollution

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    Urban networks of air-quality monitors are often too widely spaced to identify sources of air pollutants, especially if they do not disperse far from emission sources. The objectives of this study were to test the use of moss bioindicators to develop a fine-scale map of atmospherically-derived cadmium and to identify the sources of cadmium in a complex urban setting.We collected 346 samples of the moss Orthotrichum lyellii from deciduous trees in December, 2013 using a modified randomized grid-based sampling strategy across Portland, Oregon.We estimated a spatial linear model of moss cadmium levels and predicted cadmium on a 50 m grid across the city. Cadmium levels in moss were positively correlated with proximity to two stained-glass manufacturers, proximity to the Oregon– Washington border, and percent industrial land in a 500 m buffer, and negatively correlated with percent residential land in a 500 m buffer. The maps showed very high concentrations of cadmium around the two stained-glass manufacturers, neither of which were known to environmental regulators as cadmium emitters. In addition, in response to our findings, the Oregon Department of Environmental Quality placed an instrumental monitor 120 m from the larger stained-glass manufacturer in October, 2015. The monthly average atmospheric cadmium concentration was 29.4 ng/m3,which is 49 times higher than Oregon\u27s benchmark of 0.6 ng/m3, and high enough to pose a health risk from even short-term exposure. Both stained-glass manufacturers voluntarily stopped using cadmium after the monitoring results were made public, and the monthly average cadmium levels precipitously dropped to 1.1 ng/m3 for stained-glass manufacturer #1 and 0.67 ng/m3 for stained-glass manufacturer #2

    A Multi-Scale Approach to Airway Hyperresponsiveness: From Molecule to Organ

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    Airway hyperresponsiveness (AHR), a characteristic of asthma that involves an excessive reduction in airway caliber, is a complex mechanism reflecting multiple processes that manifest over a large range of length and time scales. At one extreme, molecular interactions determine the force generated by airway smooth muscle (ASM). At the other, the spatially distributed constriction of the branching airways leads to breathing difficulties. Similarly, asthma therapies act at the molecular scale while clinical outcomes are determined by lung function. These extremes are linked by events operating over intermediate scales of length and time. Thus, AHR is an emergent phenomenon that limits our understanding of asthma and confounds the interpretation of studies that address physiological mechanisms over a limited range of scales. A solution is a modular computational model that integrates experimental and mathematical data from multiple scales. This includes, at the molecular scale, kinetics, and force production of actin-myosin contractile proteins during cross-bridge and latch-state cycling; at the cellular scale, Ca2+ signaling mechanisms that regulate ASM force production; at the tissue scale, forces acting between contracting ASM and opposing viscoelastic tissue that determine airway narrowing; at the organ scale, the topographic distribution of ASM contraction dynamics that determine mechanical impedance of the lung. At each scale, models are constructed with iterations between theory and experimentation to identify the parameters that link adjacent scales. This modular model establishes algorithms for modeling over a wide range of scales and provides a framework for the inclusion of other responses such as inflammation or therapeutic regimes. The goal is to develop this lung model so that it can make predictions about bronchoconstriction and identify the pathophysiologic mechanisms having the greatest impact on AHR and its therapy

    The Identification and Verification of Hazardous Convective Cells Over Oceans Using Visible and Infrared Satellite Observations

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    Three algorithms based on geostationary visible and infrared (IR) observations are used to identify convective cells that do (or may) present a hazard to aviation over the oceans. The performance of these algorithms in detecting potentially hazardous cells is determined through verification with Tropical Rainfall Measuring Mission (TRMM) satellite observations of lightning and radar reflectivity, which provide internal information about the convective cells. The probability of detection of hazardous cells using the satellite algorithms can exceed 90% when lightning is used as a criterion for hazard, but the false-alarm ratio with all three algorithms is consistently large (40%), thereby exaggerating the presence of hazardous conditions. This shortcoming results in part from the algorithms’ dependence upon visible and IR observations, and can be traced to the widespread prevalence of deep cumulonimbi with weak updrafts but without lightning over tropical oceans, whose origin is attributed to significant entrainment during ascent

    High-Frequency InAIAs/InGaAs Metal-Insulator-Doped Semiconductor Field-Effect Transistors (MIDFETs) for Telecommunications

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    Contains an introduction and a report on one research project.Charles S. Draper Laboratories, Inc. Contract DL-H-418488Fujitsu LaboratoriesJoint Services Electronics Program Contract DAAL03-89-C-0001Joint Services Electronics Program Contract DAAL03-92-C-0001Texas Instrument

    A metastasis biomarker (MetaSite Breast™ Score) is associated with distant recurrence in hormone receptor-positive, HER2-negative early-stage breast cancer

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    Metastasis is the primary cause of death in early-stage breast cancer. We evaluated the association between a metastasis biomarker, which we call "Tumor Microenviroment of Metastasis" (TMEM), and risk of recurrence. TMEM are microanatomic structures where invasive tumor cells are in direct contact with endothelial cells and macrophages, and which serve as intravasation sites for tumor cells into the circulation. We evaluated primary tumors from 600 patients with Stage I-III breast cancer treated with adjuvant chemotherapy in trial E2197 (NCT00003519), plus endocrine therapy for hormone receptor (HR)+ disease. TMEM were identified and enumerated using an analytically validated, fully automated digital pathology/image analysis method (MetaSite Breast™), hereafter referred to as MetaSite Score (MS). The objectives were to determine the association between MS and distant relapse free interval (DRFI) and relapse free interval (RFI). MS was not associated with tumor size or nodal status, and correlated poorly with Oncotype DX Recurrence Score (r = 0.29) in 297 patients with HR+/HER2- disease. Proportional hazards models revealed a significant positive association between continuous MS and DRFI (p = 0.001) and RFI (p = 0.00006) in HR+/HER2- disease in years 0-5, and by MS tertiles for DRFI (p = 0.04) and RFI (p = 0.01), but not after year 5 or in triple negative or HER2+ disease. Multivariate models in HR+/HER- disease including continuous MS, clinical covariates, and categorical Recurrence Score ( 30) showed MS is an independent predictor for 5-year RFI (p = 0.05). MetaSite Score provides prognostic information for early recurrence complementary to clinicopathologic features and Recurrence Score.Breast Cancer Research Foundatio

    Some physical and mechanical characterization of Tunisian planted Eucalytus loxophleba and Eucalyptus salmonophloia woods

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    After the independence in 1957 and with the support of the FAO117, Eucalyptus species were planted in Tunisia in different arboreta throughout the country for close observation and adaptation to climate and soil. The objective of this study is to evaluate the physical and mechanical properties of two species planted in marginal area in Sousse (arboretum El Hanya) in the east of Tunisia (Eucalytus loxophleba and Eucalyptus salmonophloia). The moisture content, specific gravity and volumetric shrinkage were measured. The Mechanical tests were performed to evaluate the hardness, the static bending and the resistance to compression parallel to fiber direction. Preliminary results showed that Eucalytusloxophleba and Eucalyptus salmonophloia have a low dimensional stability. During the drying period, woods showed signs of collapses. On the other hand, both species were highly resistant to compression strength while they were lower on the static bending. Eucalytus loxophleba and Eucalyptus salmonophloia characteristics established within this study were similar to other Eucalyptus species from Tunisia, Morocco, Australia and Brazil. This wood may be used in furniture, structural material and/or biomass energy. (Résumé d'auteur
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