286 research outputs found

    EIT and diffusion of atomic coherence

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    We study experimentally the effect of diffusion of Rb atoms on Electromagnetically Induced Transparency (EIT) in a buffer gas vapor cell. In particular, we find that diffusion of atomic coherence in-and-out of the laser beam plays a crucial role in determining the EIT resonance lineshape and the stored light lifetime.Comment: 5 pages, 8 figure

    Random walk with barriers: Diffusion restricted by permeable membranes

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    Restrictions to molecular motion by barriers (membranes) are ubiquitous in biological tissues, porous media and composite materials. A major challenge is to characterize the microstructure of a material or an organism nondestructively using a bulk transport measurement. Here we demonstrate how the long-range structural correlations introduced by permeable membranes give rise to distinct features of transport. We consider Brownian motion restricted by randomly placed and oriented permeable membranes and focus on the disorder-averaged diffusion propagator using a scattering approach. The renormalization group solution reveals a scaling behavior of the diffusion coefficient for large times, with a characteristically slow inverse square root time dependence. The predicted time dependence of the diffusion coefficient agrees well with Monte Carlo simulations in two dimensions. Our results can be used to identify permeable membranes as restrictions to transport in disordered materials and in biological tissues, and to quantify their permeability and surface area.Comment: 8 pages, 3 figures; origin of dispersion clarified, refs adde

    Observation of the Peach Fruit Moth, Carposina sasakii, Larvae in Young Apple Fruit by Dedicated Micro-Magnetic Resonance Imaging

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    Infestation of young apple fruits by the larvae of the peach fruit moth, Carposina sasakii Matsumura (Lepidoptera: Carposinidae), was studied by a small dedicated micro-magnetic resonance imaging (MRI) apparatus using the three-dimensional (3D) gradient-echo method and the two-dimensional (2D) and 3D spin-echo methods. Changes from a young larva at 1.8 mm in length to a mature one ready to leave the fruit were observed in relation to the progression of infestation of the fruit tissues. The trace of larva intrusion was demonstrated by a series of sliced images in the 3D image data of an infested fruit, where it entered from outside the calyx, and migrated to near the vasculature around the carpel through the core. The small, dedicated MRI device was proven useful for ecological studies of the growth and movement of insect larvae in their food fruits. It can also be applied to detect the infestation of small fruits by insect larvae

    Увеличение темпов прироста запасов углеводородов с помощью инновационных технологий на примере Омской области

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    Проведен анализ перспектив нефтегазоносности Омской области на основе данных инновационной технологии квантово-оптической фильтрации космоснимков. Приведены физические принципы технологии квантово-оптической фильтрации. На примере Омской области показана эффективность применения технологии квантово-оптической фильтрации при решении задачи повышения темпов прироста запасов углеводородного сырья

    Nontypeable haemophilus influenzae induces sustained lung oxidative stress and protease expression

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    © 2015 King et al. Nontypeable Haemophilus influenzae (NTHi) is a prevalent bacterium found in a variety of chronic respiratory diseases. The role of this bacterium in the pathogenesis of lung inflammation is not well defined. In this study we examined the effect of NTHi on two important lung inflammatory processes 1), oxidative stress and 2), protease expression. Bronchoalveolar macrophages were obtained from 121 human subjects, blood neutrophils from 15 subjects, and human-lung fibroblast and epithelial cell lines from 16 subjects. Cells were stimulated with NTHi to measure the effect on reactive oxygen species (ROS) production and extracellular trap formation. We also measured the production of the oxidant, 3-nitrotyrosine (3-NT) in the lungs of mice infected with this bacterium. NTHi induced widespread production of 3-NT in mouse lungs. This bacterium induced significantly increased ROS production in human fibroblasts, epithelial cells, macrophages and neutrophils; with the highest levels in the phagocytic cells. In human macrophages NTHi caused a sustained, extracellular production of ROS that increased over time. The production of ROS was associated with the formation of macrophage extracellular trap-like structures which co-expressed the protease metalloproteinase-12. The formation of the macrophage extracellular trap-like structures was markedly inhibited by the addition of DNase. In this study we have demonstrated that NTHi induces lung oxidative stress with macrophage extracellular trap formation and associated protease expression. DNase inhibited the formation of extracellular traps

    Validation of the psychometric properties of the health-promoting lifestyle profile in a sample of Taiwanese women

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    PURPOSE: To examine the preliminary psychometric properties of the Chinese health-promoting lifestyle profile II (HPLP II) among Taiwanese women. METHODS: We conducted a secondary analysis of cross-sectional data from 137 middle-aged women in southern Taiwan. HPLP II reliability was estimated with Cronbach's alpha coefficient, and concurrent validity was estimated with Pearson's correlation between the HPLP II, the World Health Organization's abbreviated Quality of Life assessment (WHOQOL-BREF), perceived health, and demographic variables. Confirmatory factor analysis (CFA) evaluated construct validity. RESULTS: Initial CFA using a six-factor measurement model aligned with the original HPLP II, excepting the factor loading of one subsequently excluded item. CFA of the revised 51-item HPLP II yielded a good estimate of fit. Correlations between the revised instrument and the six subscales were acceptable >0.7. The Cronbach's alpha coefficient surpassed 0.7 for the revised instrument and six subscales ranged from 0.71 to 0.91. The relationships between the 51-item instrument, perceived health, WHOQOL-BREF domain scores, and demographic variables were also significantly positive. CONCLUSIONS: The revised HPLP II scale is appropriate to measure the health-promoting lifestyles of Taiwanese women.published_or_final_versionSpringer Open Choice, 21 Feb 201

    How Accessible Was Information about H1N1 Flu? Literacy Assessments of CDC Guidance Documents for Different Audiences

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    We assessed the literacy level and readability of online communications about H1N1/09 influenza issued by the Centers for Disease Control and Prevention (CDC) during the first month of outbreak. Documents were classified as targeting one of six audiences ranging in technical expertise. Flesch-Kincaid (FK) measure assessed literacy level for each group of documents. ANOVA models tested for differences in FK scores across target audiences and over time. Readability was assessed for documents targeting non-technical audiences using the Suitability Assessment of Materials (SAM). Overall, there was a main-effect by audience, F(5, 82) = 29.72, P<.001, but FK scores did not vary over time, F(2, 82) = .34, P>.05. A time-by-audience interaction was significant, F(10, 82) = 2.11, P<.05. Documents targeting non-technical audiences were found to be text-heavy and densely-formatted. The vocabulary and writing style were found to adequately reflect audience needs. The reading level of CDC guidance documents about H1N1/09 influenza varied appropriately according to the intended audience; sub-optimal formatting and layout may have rendered some text difficult to comprehend

    Rapid Detection of Infestation of Apple Fruits by the Peach Fruit Moth, Carposina sasakii Matsumura, Larvae Using a 0.2-T Dedicated Magnetic Resonance Imaging Apparatus

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    Infestation of harvested apple fruits by the peach fruit moth (Carposina sasakii Matsumura) was studied using a dedicated magnetic resonance imaging (MRI) apparatus equipped with a 0.2-T permanent magnet. Infested holes on the three-dimensional (3-D) images tracked ecological movements of peach fruit moth larvae within the food fruits, and thus in their natural habitat. Sensitive short solenoid coil and surface coil detectors were devised to shorten measurement times. The short solenoid coil detected infestation holes at a rate of 6.4 s per image by the single-slice 2-D measurement. The multi-slice 2-D measurement provided six slice images of a fruit within 2 min taken by the two detectors. These results indicate that the 0.2-T MRI apparatus allows one to distinguish sound fruits from infested ones, and also as a means for plant protection and the preservation of natural ecological systems in foreign trade
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