Science.gov

Sample records for 4d effective couplings

  1. Exploring coupled 4D-Var data assimilation using an idealised atmosphere-ocean model

    NASA Astrophysics Data System (ADS)

    Smith, Polly; Fowler, Alison; Lawless, Amos; Haines, Keith

    2014-05-01

    The successful application of data assimilation techniques to operational numerical weather prediction and ocean forecasting systems has led to an increased interest in their use for the initialisation of coupled atmosphere-ocean models in prediction on seasonal to decadal timescales. Coupled data assimilation presents a significant challenge but offers a long list of potential benefits including improved use of near-surface observations, reduction of initialisation shocks in coupled forecasts, and generation of a consistent system state for the initialisation of coupled forecasts across all timescales. In this work we explore some of the fundamental questions in the design of coupled data assimilation systems within the context of an idealised one-dimensional coupled atmosphere-ocean model. The system is based on the European Centre for Medium-Range Weather Forecasts (ECMWF) Integrated Forecast System (IFS) atmosphere model and a K-Profile Parameterisation (KKP) mixed layer ocean model developed by the National Centre for Atmospheric Science (NCAS) climate group at the University of Reading. It employs a strong constraint incremental 4D-Var scheme and is designed to enable the effective exploration of various approaches to performing coupled model data assimilation whilst avoiding many of the issues associated with more complex models. Working with this simple framework enables a greater range and quantity of experiments to be performed. Here, we will describe the development of our simplified single-column coupled atmosphere-ocean 4D-Var assimilation system and present preliminary results from a series of identical twin experiments devised to investigate and compare the behaviour and sensitivities of different coupled data assimilation methodologies. This includes comparing fully and weakly coupled assimilations with uncoupled assimilation, investigating whether coupled assimilation can eliminate or lessen initialisation shock in coupled model forecasts, and

  2. Coupled Ocean-Atmosphere 4D-Var: Formulation and Sensitivity Analysis Results

    NASA Astrophysics Data System (ADS)

    Ngodock, Hans; Carrier, Matthew; Xu, Liang; Amerault, Clark; Campbell, Tim; Rowley, Clark

    2016-04-01

    The US Navy is currently developing the first coupled ocean-atmosphere four-dimensional variational (4D-Var) data assimilation system to be used for short-term regional forecasting. This project merges the 4D-Var capabilities of the atmospheric component of the Coupled Ocean/Atmospheric Mesoscale Prediction System (COAMPS©) with the Navy Coastal Ocean Model (NCOM) through the Earth System Modeling Framework (ESMF). This will provide the coupled ocean-atmosphere forecast with a fully balanced analysis that accounts for all combined observations in both primary fluids (i.e. ocean and atmosphere). In this present work, the formulation of the system is presented in detail along with a series of adjoint sensitivity analysis results using the coupled ocean-atmosphere adjoint model. The sensitivity of the atmosphere (ocean) to each ocean (atmosphere) model variable is analyzed in detail in order to illustrate the usefulness of this approach in the coupled data assimilation system.

  3. Exploring strategies for coupled 4D-Var data assimilation using an idealised atmosphere-ocean model

    NASA Astrophysics Data System (ADS)

    Smith, Polly; Fowler, Alison; Lawless, Amos

    2015-04-01

    Coupled atmosphere-ocean data assimilation offers a long list of potential benefits, including improved use of near-surface observations, reduction of initialisation shocks in coupled forecasts and generation of a consistent system state for the initialisation of coupled forecasts across all timescales. Strongly-coupled data assimilation presents a significant challenge and so several operational centres are developing weakly-coupled assimilation systems as a first step. Here we use an idealised model framework to assess the expected benefits of moving towards coupled data assimilation in the context of incremental four dimensional variational assimilation (4D-Var). An idealised 1D atmosphere-ocean model system has been built by coupling the European Centre for Medium-Range Weather Forecasts (ECMWF) single-column atmospheric model to a single-column K-Profile Parameterisation (KPP) ocean mixed layer model developed by the National Centre for Atmospheric Science (NCAS) climate group at the University of Reading. The use of these models ensures that the simplified system retains the key elements of coupling processes in a fully coupled ocean-atmosphere model system without being overly complex. The system has the capability to run both strongly- and weakly-coupled assimilations as well as uncoupled atmosphere or ocean only assimilations, thus allowing a systematic comparison of the different strategies for treating the coupled data assimilation problem. We will describe the different coupled incremental 4D-Var data assimilation methodologies and present results from a series of identical twin experiments devised to investigate the behaviour and sensitivities of each approach. Overall, our study demonstrates that significant benefits may be expected from coupled data assimilation. When compared to uncoupled initialisation, coupled assimilation is able to produce more balanced initial analysis fields, thus reducing initialisation shock and its impact on the subsequent

  4. Effect of tumor amplitude and frequency on 4D modeling of Vero4DRT system.

    PubMed

    Miura, Hideharu; Ozawa, Shuichi; Hayata, Masahiro; Tsuda, Shintaro; Yamada, Kiyoshi; Nagata, Yasushi

    2017-01-01

    An important issue in indirect dynamic tumor tracking with the Vero4DRT system is the accuracy of the model predictions of the internal target position based on surrogate infrared (IR) marker measurement. We investigated the predictive uncertainty of 4D modeling using an external IR marker, focusing on the effect of the target and surrogate amplitudes and periods. A programmable respiratory motion table was used to simulate breathing induced organ motion. Sinusoidal motion sequences were produced by a dynamic phantom with different amplitudes and periods. To investigate the 4D modeling error, the following amplitudes (peak-to-peak: 10-40 mm) and periods (2-8 s) were considered. The 95th percentile 4D modeling error (4D-E95%) between the detected and predicted target position (μ + 2SD) was calculated to investigate the 4D modeling error. 4D-E95% was linearly related to the target motion amplitude with a coefficient of determination R(2) = 0.99 and ranged from 0.21 to 0.88 mm. The 4D modeling error ranged from 1.49 to 0.14 mm and gradually decreased with increasing target motion period. We analyzed the predictive error in 4D modeling and the error due to the amplitude and period of target. 4D modeling error substantially increased with increasing amplitude and decreasing period of the target motion.

  5. Coupled 4D-variational physical and biological data assimilation in the California Current System

    NASA Astrophysics Data System (ADS)

    Song, H.; Edwards, C. A.; Moore, A. M.; Fiechter, J.

    2012-12-01

    Coupled physical and biological data assimilation is performed within the California Current System using a 3-dimensional coupled physical-biological model using the four-dimensional variational (4DVar) method and assuming Gaussian and lognormal error distributions for physical and biological variables, respectively. Errors are assumed to be independent, yet variables are coupled by assimilation through adjoint model dynamics. Using a nutrient-phytoplankton-zooplankton-detritus (NPZD) model coupled to an ocean circulation model (the Regional Ocean Modeling System), the coupled data assimilation procedure is evaluated in a twin experiment setting and compared to two related experiments, assimilating physical data only and biological data only. Independent assimilation of physical (biological) data reduces the root-mean-squared error of physical (biological) state variables by more than 56% (46%) on average. However, the improvement in biological (physical) state variables is less than 7% (12%). In contrast, coupled data assimilation shows improvement in both physical and biological components by 57% and 52%, respectively, illustrating the superior performance of the coupled assimilation approach.

  6. Understanding the Dynamics of the Coupled Ring Current Radiation Belt System Using 4D VERB Simulations

    NASA Astrophysics Data System (ADS)

    Shprits, Y.; Kellerman, A. C.; Drozdov, A.; Orlova, K.; Spasojevic, M.

    2014-12-01

    Predicting and understanding the non-linear response of different electron populations in the inner magnetosphere, including ring current and higher energy radiation belts, has been a grand challenge since the beginning of the space age. During this past decade, there have been a number of long-term simulations that used lower energy boundary condition observations around geosynchronous orbit. In this study, we set up observations at around 15 RE and study how the combined convective-diffusive transport can result in the acceleration of keV to relativistic and ultra-relativistic energies. We show that while lower energy radial transport is dominated by the convection, higher energy transport is dominated by the diffusive radial transport. MLT dependent diffusion confidents allow us to study how difference in wave properties at different MLT can influence the dynamics of the particles. Inclusion of adiabatic changes also allows us to study the radial transport that results from pitch-angle scattering and adiabatic changes. We also show that there exists an intermediate range of energies for electrons for which both processes work simultaneously. We show the comparison of the 4D VERB simulations with the Van Allen Probes measurements.

  7. Effects of nozzle types and 2,4-D formulations on spray deposition.

    PubMed

    Contiero, Robinson L; Biffe, Denis F; Constantin, Jamil; de Oliveira, Rubem S; Braz, Guilherme B P; Lucio, Felipe R; Schleier, Jerome J

    2016-12-01

    The objective of this study was to evaluate the effects of nozzle types and 2,4-D formulations on spray deposition on different targets. Two field experiments were carried out in a completely randomized design, and treatments were arranged in a factorial scheme. Species in experiment 1 were Sumatran fleabane (Conyza sumatrensis) and Brazil pusley (Richardia brasiliensis) and in experiment 2 were soybeans (Glycine max) and Benghal dayflower (Commelina benghalensis). For both experiments, the first factor corresponded to spray nozzles with different settings (AD 110.015 - 61 and 105 L ha(-1); AD 015-D - 75 and 146 L ha(-1); XR 110.0202 - 200 L ha(-1); and ADIA-D 110.02 - 208 L ha(-1)) and the second factor consisted of two formulations of 2,4-D (amine and choline). The formulation of 2,4-D choline has contained Colex-D™ Technology. Similar or higher spray deposition was observed on the leaves and artificial targets when using 2,4-D choline as compared to the 2,4-D amine formulation, and these differences in deposition were more evident for nozzles applying lower spray volumes. Deposition was more affected by nozzle type when amine formulation was used, compared to choline formulation.

  8. Pine hollow exclosures: Effect of browsing on an aspen community sprayed with 2,4-D

    Treesearch

    Dale L. Bartos; Roy O. Harniss

    1990-01-01

    The Pine Hollow aspen (Populus tremuloides) exclosures on the Ashley National Forest in eastern Utah were sampled in 1984, 19 years after they were established. The effects of 2,4-D, wildlife, and cattle on plant succession were evaluated. Two exclosures were used to protect the sprayed area from (1) all animal use and (2) only livestock use. A third sprayed area was...

  9. [Effects of EDTA on the Reductive Dechlorination of 2,4-D by Pd/Fe].

    PubMed

    Zhou, Hong-yi; Nie, Ya-zhong; Chen, Yong; Lei, Shuang-jian

    2016-02-15

    In Pd/Fe system, zero-valent iron (ZVI) passivation layer is easily formed on the particle surface during the catalytic reductive dechlorination of chlorinated organics, hindering further dechlorination of target contaminants. In this paper, the passivation layer on the Pd/Fe particle surfaces could be eliminated by the chelation of disodium edetate (EDTA) with Fe2+, Fe3+, making the reductive dechlorination continue. The experiment investigated the effects of EDTA addition manner and dosage, pH, Pd loading and temperature on dechlorination of 2,4-dichlorophenoxyacetic acid (2,4-D) by Pd/Fe. The conclusions can be summarized as follows: (1) Phenoxyacetic acid (PA) generation ratio reached 90. 7% within 20 min with EDTA concentration of 25.0 mmol x L(-1) and flow rate of 20 mL x h(-1), while it was only 74.5% after 210 min in the system without EDTA. (2) The EDTA could chelate the Fe2+ and Fe3+ generated from the process of 2,4-D dechlorination by Pd/Fe, preventing or slowing down the formation of passivation layer, and accelerating the reduction efficiency. (3) The appropriate experimental parameters for 2,4-D removal were as follows: EDTA flow rate of 20 mL x h(-1), CEDTA of 25.0 mmol x L(-1), Pd loading of 0.050%, 200 r x min(-1), pH 4.2 and 30.0 degrees C. The removal percentage of 20.0 mg x L(-1) 2,4-D reached nearly up to 100% within 210 min under these conditions. (4) The intermediates of 2, 4-D catalytic dechlorination included 2-chlorophenoxvacetic acid (2-CPA) and trace 4-chloronhenoxyacetic acid (4-CPA), and the end product was PA.

  10. Unintended effects of the herbicides 2,4-D and dicamba on lady beetles.

    PubMed

    Freydier, Laurène; Lundgren, Jonathan G

    2016-08-01

    Weed resistance to glyphosate and development of new GM crops tolerant to 2,4-dichlorophenoxyacetic acid (2,4-D) and dicamba is expected to lead to increased use of these herbicides in cropland. The lady beetle, Coleomegilla maculata is an important beneficial insect in cropland that is commonly used as an indicator species in safety evaluations of pesticides. Here, we examined the lethal and non-lethal effects of 2,4-D and dicamba active ingredients and commercial formulations to this lady beetle species, and tested for synergistic effects of the herbicides. Second instars of lady beetles were exposed to an experimental treatment, and their mortality, development, weight, sex ratio, fecundity, and mobility was evaluated. Using similar methods, a dose-response study was conducted on 2,4-D with and without dicamba. The commercial formulation of 2,4-D was highly lethal to lady beetle larvae; the LC90 of this herbicide was 13 % of the label rate. In this case, the "inactive" ingredients were a key driver of the toxicity. Dicamba active ingredient significantly increased lady beetle mortality and reduced their body weight. The commercial formulations of both herbicides reduced the proportion of males in the lady beetle population. The herbicides when used together did not act synergistically in their toxicity toward lady beetles versus when the chemistries were used independently. Our work shows that herbicide formulations can cause both lethal and sublethal effects on non-target, beneficial insects, and these effects are sometimes driven by the "inactive" ingredients. The field-level implications of shifts in weed management practices on insect management programs should receive further attention.

  11. Effectiveness of 2,4-D and Picloram as Forestry Herbicides

    Treesearch

    Daniel G. Neary; Parshall B. Bush; Jerry L. Michael; John W. Taylor

    1986-01-01

    Foresters use 2,4-D, alone or in combination with picloram, as often as any herbcide in the South. An active analog of the plant growth hormone indole acetic acid, 2,4-D is used as a In most forest soils in the South where organic matter, moisture, and temperature are adequate, 2,4-D degrades rapidly. Amine and salt tomulations most commonly used in forestry do not...

  12. Quasibound continuum states in SiF4 (D~ 2A1) photoionization: Photoelectron-vibrational coupling

    NASA Astrophysics Data System (ADS)

    Montuoro, Raffaele; Lucchese, Robert R.; Bozek, John D.; Das, Aloke; Poliakoff, E. D.

    2007-06-01

    The authors report a fully vibrationally resolved photoelectron spectroscopy investigation of a nonplanar molecule studied over a range of excitation energies. Experimental results for all four fundamental vibrational modes are presented. In each case significant non-Franck-Condon effects are seen. The vibrational branching ratio for the totally symmetric mode ν1+ is found to be strongly affected by resonant excitation in the SiF4+ (D˜A12) photoionization channel. This is shown to be the result of two distinct shape resonances, which for the first time have been both confirmed by theoretical calculations. Vibrationally resolved Schwinger photoionization calculations are used to understand the vibronic coupling for the photoelectrons, both using ab initio and harmonic vibrational wave functions.

  13. Characterization of the Effects of Semaphorin 4D Signaling on Angiogenesis.

    PubMed

    Zhou, Hua; Yang, Ying-Hua; Basile, John R

    2017-01-01

    The semaphorins and plexins comprise a family of cysteine-rich cell surface and secreted proteins originally shown to control nerve growth and the immune response, but that have recently been implicated in a wide variety of developmental and pathological processes that are influenced by cell adhesion and migration. Along those lines, our group and others have found that Semaphorin 4D (SEMA4D) plays an important role in angiogenesis by promoting chemotaxis of endothelial cells, which express its receptor, Plexin-B1. Indeed, some neoplasms produce SEMA4D along with other pro-angiogenic proteins for the purpose of enhancing blood vessel growth into a developing neoplasm. Here we describe the application of in vitro migration and tubulogenesis assays and the directed in vivo angiogenesis assay (DIVAA) in the measurement of the angiogenic potential of cell-derived and soluble SEMA4D.

  14. New prospective 4D-CT for mitigating the effects of irregular respiratory motion

    NASA Astrophysics Data System (ADS)

    Pan, Tinsu; Martin, Rachael M.; Luo, Dershan

    2017-08-01

    Artifact caused by irregular respiration is a major source of error in 4D-CT imaging. We propose a new prospective 4D-CT to mitigate this source of error without new hardware, software or off-line data-processing on the GE CT scanner. We utilize the cine CT scan in the design of the new prospective 4D-CT. The cine CT scan at each position can be stopped by the operator when an irregular respiration occurs, and resumed when the respiration becomes regular. This process can be repeated at one or multiple scan positions. After the scan, a retrospective reconstruction is initiated on the CT console to reconstruct only the images corresponding to the regular respiratory cycles. The end result is a 4D-CT free of irregular respiration. To prove feasibility, we conducted a phantom and six patient studies. The artifacts associated with the irregular respiratory cycles could be removed from both the phantom and patient studies. A new prospective 4D-CT scanning and processing technique to mitigate the impact of irregular respiration in 4D-CT has been demonstrated. This technique can save radiation dose because the repeat scans are only at the scan positions where an irregular respiration occurs. Current practice is to repeat the scans at all positions. There is no cost to apply this technique because it is applicable on the GE CT scanner without new hardware, software or off-line data-processing.

  15. Comparative effects of the herbicides dicamba, 2,4-D and paraquat on non-green potato tuber calli.

    PubMed

    Peixoto, Franciso P; Gomes-Laranjo, José; Vicente, Joaquim A; Madeira, Victor M C

    2008-07-31

    The effects of the herbicides 1,1'-dimethyl-4,4'-bipyridylium dichloride (paraquat), 3,6-dichloro-2-metoxybenzoic acid (dicamba) and 2,4-dichlorophenoxyacetic acid (2,4-D) on cell growth of non-green potato tuber calli are described. We attempted to relate the effects with toxicity, in particular the enzymes committed to the cellular antioxidant system. Cell cultures were exposed to the herbicides for a period of 4 weeks. Cellular integrity on the basis of fluorescein release was strongly affected by 2,4-D, followed by dicamba, and was not affected by paraquat. However, the three herbicides decreased the energy charge, with paraquat and 2,4-D being very efficient. Paraquat induced catalase (CAT) activity at low concentrations (1 microM), whereas at higher concentrations, inhibition was observed. Dicamba and 2,4-D stimulated CAT as a function of concentration. Superoxide dismutase (SOD) activity was strongly stimulated by paraquat, whereas dicamba and 2,4-D were efficient only at higher concentrations. Glutathione reductase (GR) activity was induced by all the herbicides, suggesting that glutathione and glutathione-dependent enzymes are putatively involved in the detoxification of these herbicides. Paraquat slightly inhibited glutathione S-transferase (GST), whereas 2,4-D and dicamba promoted significant activation. These results indicate that the detoxifying mechanisms for 2,4-D and dicamba may be different from the mechanisms of paraquat detoxification. However, the main cause of cell death induced by paraquat and 2,4-D is putatively related with the cell energy charge decrease.

  16. Digit ratio (2D:4D) and month of birth: A link to the solstitial-melatonin-testosterone effect.

    PubMed

    Szwed, Anita; Kosinska, Magdalena; Manning, John T

    2017-01-01

    Digit ratio (2D:4D) is a sexually dimorphic trait and its determination in utero is influenced by testosterone. The solstitial-melatonin-testosterone hypothesis posits that melatonin inhibits the production of foetal testosterone and melatonin levels are at their lowest in months when light levels are high. We test the relationship between 2D:4D, month-of-birth and light levels. We recruited participants whose year of birth was spread across the 20th Century. 323 Polish men and women. Finger lengths, month-of-birth, mean daylight hours per month in and around Poznan, Poland. Our sample was born between 1907 and 1997. In comparison to late-Spring births, late-Autumn births had low right-left 2D:4D (high prenatal testosterone). Regarding light levels, there were significant relationships between low right 2D:4D and right-left 2D:4D (high prenatal testosterone) and long days at the end of the 1st trimester. These relationships were strongest for participants born in the first half of the 20th Century. Participants born in the late-Autumn and who experienced long days in the 2nd and 3rd prenatal months had low 2D:4D. The effects were strongest for early 20th Century births where photoperiods would be less disrupted by artificial light. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  17. Unintended effects of the herbicides 2,4-D and dicamba on lady beetles

    USDA-ARS?s Scientific Manuscript database

    Weed resistance to glyphosate and development of new GM crops tolerant to 2,4-dichlorophenoxyacetic acid (2,4-D) and dicamba is expected to lead to increased use of these herbicides in cropland. The lady beetle, Coleomegilla maculata is an important beneficial insect in cropland that is commonly use...

  18. Estimation of reservoir fluid saturation from 4D seismic data: effects of noise on seismic amplitude and impedance attributes

    NASA Astrophysics Data System (ADS)

    Souza, Rafael; Lumley, David; Shragge, Jeffrey

    2017-02-01

    Time-lapse (4D) seismic data sets have proven to be extremely useful for reservoir monitoring. Seismic-derived impedance estimates are commonly used as a 4D attribute to constrain updates to reservoir fluid flow models. However, 4D seismic estimates of P-wave impedance can contain significant errors associated with the effects of seismic noise and the inherent instability of inverse methods. These errors may compromise the geological accuracy of the reservoir model leading to incorrect reservoir model property updates and incorrect reservoir fluid flow predictions. To evaluate such errors and uncertainties we study two time-lapse scenarios based on 1D and 3D reservoir model examples, thereby exploring a number of inverse theory concepts associated with the instability and error of coloured inversion operators and their dependence on seismic noise levels. In the 1D example, we show that inverted band-limited impedance changes have a smaller root-mean-square (RMS) error in comparison to their absolute broadband counterpart for signal-to-noise ratios 10 and 5 while for signal-to-noise ratio (S/N)  =  3 both inversion methods present similarly high errors. In the 3D example we use an oilfield benchmark case based on the Namorado Field in Campos Basin, Brazil. We introduce a histogram similarity measure to quantify the impact of seismic noise on maps of 4D seismic amplitude and impedance changes as a function of S/N levels, which indicate that amplitudes are less sensitive to 4D seismic noise than impedances. The RMS errors in the estimates of water saturation changes derived from 4D seismic amplitudes are also smaller than for 4D seismic impedances, over a wide range of typical seismic noise levels. These results quantitatively demonstrate that seismic amplitudes can be more accurate and robust than seismic impedances for quantifying water saturation changes with 4D seismic data, and emphasize that seismic amplitudes may be more reliable to update fluid flow

  19. TU-F-17A-03: A 4D Lung Phantom for Coupled Registration/Segmentation Evaluation

    SciTech Connect

    Markel, D; El Naqa, I; Levesque, I

    2014-06-15

    Purpose: Coupling the processes of segmentation and registration (regmentation) is a recent development that allows improved efficiency and accuracy for both steps and may improve the clinical feasibility of online adaptive radiotherapy. Presented is a multimodality animal tissue model designed specifically to provide a ground truth to simultaneously evaluate segmentation and registration errors during respiratory motion. Methods: Tumor surrogates were constructed from vacuum sealed hydrated natural sea sponges with catheters used for the injection of PET radiotracer. These contained two compartments allowing for two concentrations of radiotracer mimicking both tumor and background signals. The lungs were inflated to different volumes using an air pump and flow valve and scanned using PET/CT and MRI. Anatomical landmarks were used to evaluate the registration accuracy using an automated bifurcation tracking pipeline for reproducibility. The bifurcation tracking accuracy was assessed using virtual deformations of 2.6 cm, 5.2 cm and 7.8 cm of a CT scan of a corresponding human thorax. Bifurcations were detected in the deformed dataset and compared to known deformation coordinates for 76 points. Results: The bifurcation tracking accuracy was found to have a mean error of −0.94, 0.79 and −0.57 voxels in the left-right, anterior-posterior and inferior-superior axes using a 1×1×5 mm3 resolution after the CT volume was deformed 7.8 cm. The tumor surrogates provided a segmentation ground truth after being registered to the phantom image. Conclusion: A swine lung model in conjunction with vacuum sealed sponges and a bifurcation tracking algorithm is presented that is MRI, PET and CT compatible and anatomically and kinetically realistic. Corresponding software for tracking anatomical landmarks within the phantom shows sub-voxel accuracy. Vacuum sealed sponges provide realistic tumor surrogate with a known boundary. A ground truth with minimal uncertainty is thus

  20. An ecological risk assessment of the exposure and effects of 2,4-D acid to rainbow trout (Onchorhyncus mykiss).

    PubMed

    Fairchild, J F; Feltz, K P; Allert, A L; Sappington, L C; Nelson, K J; Valle, J A

    2009-05-01

    Numerous state and federal agencies are increasingly concerned with the rapid expansion of invasive, noxious weeds across the United States. Herbicides are frequently applied as weed control measures in forest and rangeland ecosystems that frequently overlap with critical habitats of threatened and endangered fish species. However, there is little published chronic toxicity data for herbicides and fish that can be used to assess ecological risk of herbicides in aquatic environments. We conducted 96-h flowthrough acute and 30-day chronic toxicity studies with swim-up larvae and juvenile rainbow trout (Onchorhyncus mykiss) exposed to the free acid form of 2,4-D. Juvenile rainbow trout were acutely sensitive to 2,4-D acid equivalent at 494 mg/L (95% confidence interval [CI] 334-668 mg/L; 96-h ALC(50)). Accelerated life-testing procedures, used to estimate chronic mortality from acute data, predicted that a 30-day exposure of juvenile rainbow trout to 2,4-D would result in 1% and 10% mortality at 260 and 343 mg/L, respectively. Swim-up larvae were chronically more sensitive than juveniles using growth as the measurement end point. The 30-day lowest observable effect concentration (LOEC) of 2,4-D on growth of swim-up larvae was 108 mg/L, whereas the 30-day no observable effect concentration (NOEC) was 54 mg/L. The 30-day maximum acceptable toxicant concentration (MATC) of 2,4-D for rainbow trout, determined as the geometric mean of the NOEC and the LOEC, was 76 mg/L. The acute:chronic ratio was 6.5 (i.e., 494/76). We observed no chronic effects on growth of juvenile rainbow trout at the highest concentration tested (108 mg/L). Worst-case aquatic exposures to 2,4-D (4 mg/L) occur when the herbicide is directly applied to aquatic ecosystems for aquatic weed control and resulted in a 30-day safety factor of 19 based on the MATC for growth (i.e., 76/4). Highest nontarget aquatic exposures to 2,4-D applied following terrestrial use is calculated at 0.136 mg/L and resulted in

  1. An ecological risk assessment of the exposure and effects of 2,4-D acid to rainbow trout (Onchorhyncus mykiss)

    USGS Publications Warehouse

    Fairchild, J.F.; Feltz, K.P.; Allert, A.L.; Sappington, L.C.; Nelson, K.J.; Valle, J.A.

    2009-01-01

    Numerous state and federal agencies are increasingly concerned with the rapid expansion of invasive, noxious weeds across the United States. Herbicides are frequently applied as weed control measures in forest and rangeland ecosystems that frequently overlap with critical habitats of threatened and endangered fish species. However, there is little published chronic toxicity data for herbicides and fish that can be used to assess ecological risk of herbicides in aquatic environments. We conducted 96-h flowthrough acute and 30-day chronic toxicity studies with swim-up larvae and juvenile rainbow trout (Onchorhyncus mykiss) exposed to the free acid form of 2,4-D. Juvenile rainbow trout were acutely sensitive to 2,4-D acid equivalent at 494 mg/L (95% confidence interval [CI] 334-668 mg/L; 96-h ALC50). Accelerated life-testing procedures, used to estimate chronic mortality from acute data, predicted that a 30-day exposure of juvenile rainbow trout to 2,4-D would result in 1% and 10% mortality at 260 and 343 mg/L, respectively. Swim-up larvae were chronically more sensitive than juveniles using growth as the measurement end point. The 30-day lowest observable effect concentration (LOEC) of 2,4-D on growth of swim-up larvae was 108 mg/L, whereas the 30-day no observable effect concentration (NOEC) was 54 mg/L. The 30-day maximum acceptable toxicant concentration (MATC) of 2,4-D for rainbow trout, determined as the geometric mean of the NOEC and the LOEC, was 76 mg/L. The acute:chronic ratio was 6.5 (i.e., 494/76). We observed no chronic effects on growth of juvenile rainbow trout at the highest concentration tested (108 mg/L). Worst-case aquatic exposures to 2,4-D (4 mg/L) occur when the herbicide is directly applied to aquatic ecosystems for aquatic weed control and resulted in a 30-day safety factor of 19 based on the MATC for growth (i.e., 76/4). Highest nontarget aquatic exposures to 2,4-D applied following terrestrial use is calculated at 0.136 mg/L and resulted in a

  2. Putting a finger on potential predictors of oral contraceptive side effects: 2D:4D and middle-phalangeal hair.

    PubMed

    Oinonen, Kirsten A

    2009-06-01

    Many women experience emotional or physical side effects when taking oral contraceptives (OCs). Despite the potential impact on women's health and well-being, there are no valid methods to screen women for their risk of OC side effects. The present paper presents the results of two studies where anthropometric indicators of androgen exposure, 2D:4D and middle-phalangeal hair, were examined for their potential as predictors of OC side effects. In study 1, 2D:4D was associated with women's reports of a history of: (a) negative mood side effects; (b) discontinuation due to negative mood side effects; (c) specific mood side effects (i.e., crying, sadness, and altered trust in one's partners) and (d) specific physical side effects (i.e., headaches, fatigue, and decreased sex drive). In study 2, 2D:4D and/or middle-phalangeal hair was/were associated with a reported history of: (a) discontinuation due to negative mood side effects; (b) specific mood-related side effects (i.e., negative mood, disrupted sleep, increased aggression, and altered trust in one's partner) and (c) specific physical side effects (i.e., headaches, decreased menstrual cramps, and increased sex drive/arousal). The general pattern was that adverse OC side effects were experienced by women with lower 2D:4D and fewer middle-phalangeal hairs. Almost all relationships remained significant when response bias was controlled. These results suggest a possible role for prenatal testosterone exposure and both androgen action and sensitivity in women's experience of OC side effects. Furthermore, these two digit measures may be useful predictors of hormonal contraceptive side effects in women.

  3. Effect of heart rate on CT angiography using the enhanced cardiac model of the 4D NCAT

    NASA Astrophysics Data System (ADS)

    Segars, W. P.; Taguchi, K.; Fung, G. S. K.; Fishman, E. K.; Tsui, B. M. W.

    2006-03-01

    We investigate the effect of heart rate on the quality and artifact generation in coronary artery images obtained using multi-slice computed tomography (MSCT) with the purpose of finding the optimal time resolution for data acquisition. To perform the study, we used the 4D NCAT phantom, a computer model of the normal human anatomy and cardiac and respiratory motions developed in our laboratory. Although capable of being far more realistic, the 4D NCAT cardiac model was originally designed for low-resolution imaging research, and lacked the anatomical detail to be applicable to high-resolution CT. In this work, we updated the cardiac model to include a more detailed anatomy and physiology based on high-resolution clinical gated MSCT data. To demonstrate its utility in high-resolution dynamic CT imaging research, the enhanced 4D NCAT was then used in a pilot simulation study to investigate the effect of heart rate on CT angiography. The 4D NCAT was used to simulate patients with different heart rates (60-120 beats/minute) and with various cardiac plaques of known size and location within the coronary arteries. For each simulated patient, MSCT projection data was generated with data acquisition windows ranging from 100 to 250 ms centered within the quiet phase (mid-diastole) of the heart using an analytical CT projection algorithm. CT images were reconstructed from the projection data, and the contrast of the plaques was then measured to assess the effect of heart rate and to determine the optimal time resolution required for each case. The 4D NCAT phantom with its realistic model for the cardiac motion was found to provide a valuable tool from which to optimize CT cardiac applications. Our results indicate the importance of optimizing the time resolution with regard to heart rate and plaque location for improved CT images at a reduced patient dose.

  4. [The effect of the dioxin-containing herbicide 2,4-D on the hormonal status of experimental animals].

    PubMed

    Gil'manov, A Zh; Galimov, Sh N; Kamilov, F Kh; Davletov, E G; Shchepanskiĭ, V O

    1997-01-01

    The article presents studies of hormonal state in rats under daily or 20-day peroral administration of variable doses of 2,4-D herbicide containing dioxine. Changed levels of thyroid hormones, insulin, cortisol, testosterone and estradiol appeared to be divergent and dose-dependent, proving direct toxic effects of the herbicide in endocrine organs, altered hormonal effects in target organs and disorders of peripheral hormonal metabolism.

  5. Effect of Dissemination of 2,4-Dichlorophenoxyacetic Acid (2,4-D) Degradation Plasmids on 2,4-D Degradation and on Bacterial Community Structure in Two Different Soil Horizons

    PubMed Central

    Dejonghe, Winnie; Goris, Johan; El Fantroussi, Saïd; Höfte, Monica; De Vos, Paul; Verstraete, Willy; Top, Eva M.

    2000-01-01

    Transfer of the 2,4-dichlorophenoxyacetic acid (2,4-D) degradation plasmids pEMT1 and pJP4 from an introduced donor strain, Pseudomonas putida UWC3, to the indigenous bacteria of two different horizons (A horizon, depth of 0 to 30 cm; B horizon, depth of 30 to 60 cm) of a 2,4-D-contaminated soil was investigated as a means of bioaugmentation. When the soil was amended with nutrients, plasmid transfer and enhanced degradation of 2,4-D were observed. These findings were most striking in the B horizon, where the indigenous bacteria were unable to degrade any of the 2,4-D (100 mg/kg of soil) during at least 22 days but where inoculation with either of the two plasmid donors resulted in complete 2,4-D degradation within 14 days. In contrast, in soils not amended with nutrients, inoculation of donors in the A horizon and subsequent formation of transconjugants (105 CFU/g of soil) could not increase the 2,4-D degradation rate compared to that of the noninoculated soil. However, donor inoculation in the nonamended B-horizon soil resulted in complete degradation of 2,4-D within 19 days, while no degradation at all was observed in noninoculated soil during 89 days. With plasmid pEMT1, this enhanced degradation seemed to be due only to transconjugants (105 CFU/g of soil), since the donor was already undetectable when degradation started. Denaturing gradient gel electrophoresis (DGGE) of 16S rRNA genes showed that inoculation of the donors was followed by a shift in the microbial community structure of the nonamended B-horizon soils. The new 16S rRNA gene fragments in the DGGE profile corresponded with the 16S rRNA genes of 2,4-D-degrading transconjugant colonies isolated on agar plates. This result indicates that the observed change in the community was due to proliferation of transconjugants formed in soil. Overall, this work clearly demonstrates that bioaugmentation can constitute an effective strategy for cleanup of soils which are poor in nutrients and microbial activity

  6. Effects of Supplemental Energy on Protein Balance during 4-d Arctic Military Training.

    PubMed

    Margolis, Lee M; Murphy, Nancy E; Martini, Svein; Gundersen, Yngvar; Castellani, John W; Karl, J Philip; Carrigan, Christopher T; Teien, Hilde-Kristin; Madslien, Elisabeth-Henie; Montain, Scott J; Pasiakos, Stefan M

    2016-08-01

    Soldiers often experience negative energy balance during military operations that diminish whole-body protein retention, even when dietary protein is consumed within recommended levels (1.5-2.0 g·kg·d). The objective of this study is to determine whether providing supplemental nutrition spares whole-body protein by attenuating the level of negative energy balance induced by military training and to assess whether protein balance is differentially influenced by the macronutrient source. Soldiers participating in 4-d arctic military training (AMT) (51-km ski march) were randomized to receive three combat rations (CON) (n = 18), three combat rations plus four 250-kcal protein-based bars (PRO, 20 g protein) (n = 28), or three combat rations plus four 250-kcal carbohydrate-based bars daily (CHO, 48 g carbohydrate) (n = 27). Energy expenditure (D2O) and energy intake were measured daily. Nitrogen balance (NBAL) and protein turnover were determined at baseline (BL) and day 3 of AMT using 24-h urine and [N]-glycine. Protein and carbohydrate intakes were highest (P < 0.05) for PRO (mean ± SD, 2.0 ± 0.3 g·kg·d) and CHO (5.8 ± 1.3 g·kg·d), but only CHO increased (P < 0.05) energy intake above CON. Energy expenditure (6155 ± 515 kcal·d), energy balance (-3313 ± 776 kcal·d), net protein balance (NET) (-0.24 ± 0.60 g·d), and NBAL (-68.5 ± 94.6 mg·kg·d) during AMT were similar between groups. In the combined cohort, energy intake was associated (P < 0.05) with NET (r = 0.56) and NBAL (r = 0.69), and soldiers with the highest energy intake (3723 ± 359 kcal·d, 2.11 ± 0.45 g protein·kg·d, 6.654 ± 1.16 g carbohydrate·kg·d) achieved net protein balance and NBAL during AMT. These data reinforce the importance of consuming sufficient energy during periods of high energy expenditure to mitigate the consequences of negative energy balance and attenuate whole-body protein loss.

  7. Effects of quantum noise in 4D-CT on deformable image registration and derived ventilation data

    NASA Astrophysics Data System (ADS)

    Latifi, Kujtim; Huang, Tzung-Chi; Feygelman, Vladimir; Budzevich, Mikalai M.; Moros, Eduardo G.; Dilling, Thomas J.; Stevens, Craig W.; van Elmpt, Wouter; Dekker, Andre; Zhang, Geoffrey G.

    2013-11-01

    Quantum noise is common in CT images and is a persistent problem in accurate ventilation imaging using 4D-CT and deformable image registration (DIR). This study focuses on the effects of noise in 4D-CT on DIR and thereby derived ventilation data. A total of six sets of 4D-CT data with landmarks delineated in different phases, called point-validated pixel-based breathing thorax models (POPI), were used in this study. The DIR algorithms, including diffeomorphic morphons (DM), diffeomorphic demons (DD), optical flow and B-spline, were used to register the inspiration phase to the expiration phase. The DIR deformation matrices (DIRDM) were used to map the landmarks. Target registration errors (TRE) were calculated as the distance errors between the delineated and the mapped landmarks. Noise of Gaussian distribution with different standard deviations (SD), from 0 to 200 Hounsfield Units (HU) in amplitude, was added to the POPI models to simulate different levels of quantum noise. Ventilation data were calculated using the ΔV algorithm which calculates the volume change geometrically based on the DIRDM. The ventilation images with different added noise levels were compared using Dice similarity coefficient (DSC). The root mean square (RMS) values of the landmark TRE over the six POPI models for the four DIR algorithms were stable when the noise level was low (SD <150 HU) and increased with added noise when the level is higher. The most accurate DIR was DD with a mean RMS of 1.5 ± 0.5 mm with no added noise and 1.8 ± 0.5 mm with noise (SD = 200 HU). The DSC values between the ventilation images with and without added noise decreased with the noise level, even when the noise level was relatively low. The DIR algorithm most robust with respect to noise was DM, with mean DSC = 0.89 ± 0.01 and 0.66 ± 0.02 for the top 50% ventilation volumes, as compared between 0 added noise and SD = 30 and 200 HU, respectively. Although the landmark TRE were stable with low noise, the

  8. Development and validation of a capillary electrophoresis method with capacitively coupled contactless conductivity detection (CE-C(4) D) for the analysis of amikacin and its related substances.

    PubMed

    El-Attug, Mohamed Nouri; Adams, Erwin; Van Schepdael, Ann

    2012-09-01

    Amikacin is a semisynthetic aminoglycoside antibiotic derived from kanamycin A that lacks a strong UV absorbing chromophore or fluorophore. Due to the physicochemical properties of amikacin and its related substances, CE in combination with capacitively coupled contactless conductivity detection (CE-C(4) D) was chosen. The optimized separation method uses a BGE composed of 20 mM MES adjusted to pH 6.6 by l-histidine and 0.3 mM CTAB that was added as flow modifier in a concentration below the CMC. Ammonium acetate 20 mg.L(-1) was used as internal standard. 30 kV was applied in reverse polarity on a fused silica capillary (73/48 cm; 75 μm id). The optimized separation was obtained in less than 6 min with good linearity (R(2) = 0.9996) for amikacin base. It shows a good precision expressed as RSD on relative peak areas equal to 0.1 and 0.7% for intraday and interday, respectively. The LOD and LOQ are 0.5 mg.L(-1) and 1.7 mg.L(-1) , respectively.

  9. Dietary olive oil effect on antioxidant status and fatty acid profile in the erythrocyte of 2,4-D- exposed rats

    PubMed Central

    2010-01-01

    Background Oxidative stress produced by reactive oxygen species (ROS) has been linked to the development of several diseases such as cardiovascular, cancer, and neurodegenerative diseases. This study investigates the possible protective effect of extra virgin olive oil (EVOO), lipophilic fraction (OOLF) and hydrophilic fraction (OOHF) on oxidative stress and fatty acid profile of erythrocytes in 2,4-D treated rats. Methods Male Wistar rats were divided randomly into eight groups: control (C), (2,4-D) at a dose of 5 mg/kg b.w., (2,4-D/EVOO) was given 2,4-D plus EVOO, (2,4-D/OOHF) that received 2,4-D plus hydrophilic fraction, (2,4-D/OOLF) treated with 2,4-D plus lipophilic fraction, (EVOO) that received only EVOO, (OOHF) was given hydrophilic fraction and (OOLF) treated with lipophilic fraction. These components were daily administered by gavages for 4 weeks. Results 2,4-D treatment lead to decrease of antioxidant enzyme activities, namely, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR) associated with a higher amount of MDA level. Erythrocyte membranes' fatty acid composition was also significantly modified with 2,4-D exposure. EVOO and hydrophilic fraction supplemented to rats with or not 2,4-D treatment enhanced the antioxidant enzyme activities and reduced the MDA level. However, lipophilic fraction did not show any improvement in oxidative damage induced by 2,4-D in spite its richness in MUFA and vitamins. Conclusion EVOO administered to 2,4-D-treated rats protected erythrocyte membranes against oxidative damage by means of preventing excessive lipid peroxidation to increase the MUFA composition and increase maintaining antioxidants enzymes at normal concentrations. PMID:20738870

  10. Quantum gravity effects on the thermodynamic stability of 4D Schwarzschild black hole

    NASA Astrophysics Data System (ADS)

    El-Menoufi, Basem Kamal

    2017-08-01

    Based on the Euclidean approach, we consider the effects of quantum gravity and mass-less matter on the thermodynamic properties of Schwarzschild black hole. The techniques of effective field theory are utilized to analytically construct the partition function at the one-loop level. Using the non-local heat kernel formalism, the partition function is expressed as a curvature expansion. We extensively discuss the effect of the corrections on the thermodynamic stability. The one-loop free energy shows, remarkably, that a large number of gauge fields is able to render Schwarzschild black hole thermodynamically stable. The black hole mass at which stability is achieved scales as √{N} in Planck units, where N is the number of gauge fields, and is independent of any UV completion of quantum gravity.

  11. Nonperturbative corrections to 4D string theory effective actions from SL(2,Z) duality and supersymmetry.

    PubMed

    Robles-Llana, Daniel; Rocek, Martin; Saueressig, Frank; Theis, Ulrich; Vandoren, Stefan

    2007-05-25

    We find the D(-1)- and D1-brane instanton contributions to the hypermultiplet moduli space of type IIB string compactifications on Calabi-Yau threefolds. These combine with known perturbative and world sheet instanton corrections into a single modular invariant function that determines the hypermultiplet low-energy effective action.

  12. Transient effects of 2,4-dichlorophenoxyacetic acid (2,4-D) exposure on some metabolic and free radical processes in goldfish white muscle.

    PubMed

    Kubrak, Olga I; Atamaniuk, Tetiana M; Husak, Viktor V; Lushchak, Volodymyr I

    2013-09-01

    This study aims to assess effects of 96 h goldfish exposure to 1, 10 and 100 mg/L of the herbicide, 2,4-dichlorophenoxyacetic acid (2,4-D), on metabolic indices and free radical process markers in white muscle of a commercial fish, the goldfish Carassius auratus L. Most oxidative stress markers and antioxidant enzymes were not affected at 2,4-D fish treatment. 2,4-D fish exposure induced the elevated levels of total (by 46% and 40%) and reduced (by 77% and 73%) glutathione in muscles of goldfish of 10 mg/L 2,4-D and recovery (after 100 mg/L of 2,4-D exposure) groups, respectively. However, in muscles of 100 mg/L 2,4-D exposed goldfish these parameters were depleted (by 47% and 64%). None of investigated parameters of protein and carbohydrate metabolisms changed in white muscles of 2,4-D exposed fish, with exception of lactate dehydrogenase activity, which was slightly (by 11-15%) elevated in muscles of goldfish exposed to 10-100 mg/L of 2,4-D, but also recovered. Thus, the short term exposure of goldfish to the selected concentrations of 2,4-D does not substantially affect their white muscle, suggesting the absence of any effect under the environmentally relevant concentrations. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Impact of respiratory motion on variable relative biological effectiveness in 4D-dose distributions of proton therapy.

    PubMed

    Ulrich, Silke; Wieser, Hans-Peter; Cao, Wenhua; Mohan, Radhe; Bangert, Mark

    2017-08-22

    Organ motion during radiation therapy with scanned protons leads to deviations between the planned and the delivered physical dose. Using a constant relative biological effectiveness (RBE) of 1.1 linearly maps these deviations into RBE-weighted dose. However, a constant value cannot account for potential nonlinear variations in RBE suggested by variable RBE models. Here, we study the impact of motion on recalculations of RBE-weighted dose distributions using a phenomenological variable RBE model. 4D-dose calculation including variable RBE was implemented in the open source treatment planning toolkit matRad. Four scenarios were compared for one field and two field proton treatments for a liver cancer patient assuming (α∕β)x = 2 Gy and (α∕β)x = 10 Gy: (A) the optimized static dose distribution with constant RBE, (B) a static recalculation with variable RBE, (C) a 4D-dose recalculation with constant RBE and (D) a 4D-dose recalculation with variable RBE. For (B) and (D), the variable RBE was calculated by the model proposed by McNamara. For (C), the physical dose was accumulated with direct dose mapping; for (D), dose-weighted radio-sensitivity parameters of the linear quadratic model were accumulated to model synergistic irradiation effects on RBE. Dose recalculation with variable RBE led to an elevated biological dose at the end of the proton field, while 4D-dose recalculation exhibited random deviations everywhere in the radiation field depending on the interplay of beam delivery and organ motion. For a single beam treatment assuming (α∕β)x = 2 Gy, D95% was 1.98 Gy (RBE) (A), 2.15 Gy (RBE) (B), 1.81 Gy (RBE) (C) and 1.98 Gy (RBE) (D). The homogeneity index was 1.04 (A), 1.08 (B), 1.23 (C) and 1.25 (D). For the studied liver case, intrafractional motion did not reduce the modulation of the RBE-weighted dose postulated by variable RBE models for proton treatments.

  14. Coulomb Correlations in 4d and 5d Oxides from First Principles - or How Spin-Orbit Materials choose their Effective Orbital Degeneracies.

    PubMed

    Martins, Cyril; Aichhorn, Markus; Biermann, Silke

    2017-03-06

    The interplay of spin-orbit coupling and Coulomb correlations has become a hot topic in condensed matter theory and is especially at stake in 4d and 5d transition metal oxides, like iridates or rhodates. Here, we review recent advances in dynamical mean-field theory(DMFT)-based electronic structure calculations for treating such compounds, introducing all necessary implementation details. We also discuss the evaluation of Hubbard interactions in spin-orbit materials. As an example, we perform DMFT calculations on insulating strontium iridate (Sr2IrO4) and its 4d metallic counterpart strontium rhodate (Sr2RhO4). While a Mott-insulating state is obtained for Sr2IrO4 in its paramagnetic phase, the obtained spectral properties and Fermi surfaces for Sr2RhO4 show excellent agreement with available experimental data. We finally discuss the electronic structure of these two compounds by introducing the notion of effective spin-orbital degeneracy as the key quantity that determines the correlation strength. We stress that effective spin-orbital degeneracy introduces an additional axis into the conventional picture of a phase diagram based on filling and on the ratio of interactions to bandwidth, in analogy with the degeneracy controled Mott transition in d1 perovskites.

  15. Coulomb correlations in 4d and 5d oxides from first principles—or how spin-orbit materials choose their effective orbital degeneracies

    NASA Astrophysics Data System (ADS)

    Martins, C.; Aichhorn, M.; Biermann, S.

    2017-07-01

    The interplay of spin-orbit coupling and Coulomb correlations has become a hot topic in condensed matter theory and is especially important in 4d and 5d transition metal oxides, like iridates or rhodates. Here, we review recent advances in dynamical mean-field theory (DMFT)-based electronic structure calculations for treating such compounds, introducing all necessary implementation details. We also discuss the evaluation of Hubbard interactions in spin-orbit materials. As an example, we perform DMFT calculations on insulating strontium iridate (Sr2IrO4) and its 4d metallic counterpart, strontium rhodate (Sr2RhO4). While a Mott-insulating state is obtained for Sr2IrO4 in its paramagnetic phase, the spectral properties and Fermi surfaces obtained for Sr2RhO4 show excellent agreement with available experimental data. Finally, we discuss the electronic structure of these two compounds by introducing the notion of effective spin-orbital degeneracy as the key quantity that determines the correlation strength. We stress that effective spin-orbital degeneracy introduces an additional axis into the conventional picture of a phase diagram based on filling and on the ratio of interactions to bandwidth, analogous to the degeneracy-controlled Mott transition in d1 perovskites.

  16. Thermal cure effects on electromechanical properties of conductive wires by direct ink write for 4D printing and soft machines

    NASA Astrophysics Data System (ADS)

    Mu, Quanyi; Dunn, Conner K.; Wang, Lei; Dunn, Martin L.; Qi, H. Jerry; Wang, Tiejun

    2017-04-01

    Recent developments in soft materials and 3D printing are promoting the rapid development of novel technologies and concepts, such as 4D printing and soft machines, that in turn require new methods for fabricating conductive materials. Despite the ubiquity of silver nanoparticles (NPs) in the conducting electrodes of printed electronic devices, their potential use in stretchable conductors has not been fully explored in 4D printing and soft machines. This paper studies the effect of thermal cure conditions on conductivity and electro-mechanical behaviors of silver ink by the direct ink write (DIW) printing approach. We found that the electro-mechanical properties of silver wires can be tailored by controlling cure time and cure temperature to achieve conductivity as well as stretchability. For the silver NP ink we used in the experiments, silver wires cured at 80 °C for 10–30 min have conductivity >1% bulk silver, Young’s modulus <100 MPa, yield strain ∼9%, and can retain conductivity up to 300% strain. In addition, under stress controlled cyclic loading/unloading conditions, the resistance of these wires is only about 1.3 times the initial value after the 100th repeat cycle (7.6% maximum strain in the first cycle). Silver wires cured at 120 °C for 10–20 min are more sensitive to strain and have a yield strain of around 6%. These properties indicate that the silver ink can be used to fabricate stretchable electrodes and flex sensors. Using the DIW fabrication method, we printed silver ink patterns on the surface of 3D printed polymer parts, with the future goal of constructing fully 3D printed arbitrarily formed soft and stretchable devices and of applying them to 4D printing. We demonstrated a fully printed functional soft-matter sensor and a circuit element that can be stretched by as much as 45%.

  17. Effects of different concentrations of 2,4-D and BAP on somatic embryogenesis induction in saffron (Crocus sativus L.).

    PubMed

    Rajabpoor, Sh; Azghandi, A V; Saboora, A

    2007-11-01

    To optimize an in vitro protocol for propagation of saffron through somatic embryogenesis, effects of various concentrations of 2,4-D ( 0, 0.25, 0.5, 1, 2, 4 and 8 mg L(-1)) in combination with BAP (0, 0.25, 0.5, 1, 2, 4 and 8 mg L(-1)) were studied. Surface-sterilized corms were cut transversally into equal portions and the upper or lower parts were used separately as explants. All treatments were maintained in the darkness at 24 +/- 2 degrees C. After 70 days, the first globular embryos were observed and the number of embryos on each explant reached to its maximum 3 months after culture. Statistical analysis showed that there were significant differences between treatments regarding the number of embryos induced on each explant. The most effective treatment was 2.0 mg L(-1) 2,4-D + 1.0 mg L(-1) BAP for both types of explant (inducing 6.5 +/- 1.3 and 35.95 +/- 4.9 embryos on each explant for the upper and lower parts, respectively). The average percentages of explants showing embryogenic response were 33.3 and 93.3% for the upper and the lower part of corm tissue respectively in this treatment. Complementary studies are in progress to optimize maturation and germination stages of these somatic embryos.

  18. The effect of different adaptation strengths on image quality and radiation dose using Siemens Care Dose 4D.

    PubMed

    Söderberg, Marcus; Gunnarsson, Mikael

    2010-01-01

    The purpose of this study was to evaluate the effect of different choices of adaptation strengths on image quality and radiation exposure to the patient with Siemens automatic exposure control system called CARE Dose 4D. An anthropomorphic chest phantom was used to simulate the patient and computed tomography scans were performed with a Siemens SOMATOM Sensation 16 and 64. Owing to adaptation strengths, a considerable reduction (26.6-51.5 % and 27.5-49.5 % for Sensation 16 and Sensation 64, respectively) in the radiation dose was found when compared with using a fixed tube current. There was a substantial difference in the image quality (image noise) between the adaptation strengths. Independent of selected adaptation strengths, the level of image noise throughout the chest phantom increased when CARE Dose 4D was used (p < 0.0001). We conclude that the adaptation strengths can be used to obtain user-specified modifications to image quality or radiation exposure to the patient.

  19. Estimation of turbulent kinetic energy using 4D phase-contrast MRI: Effect of scan parameters and target vessel size.

    PubMed

    Ha, Hojin; Hwang, Dongha; Kim, Guk Bae; Kweon, Jihoon; Lee, Sang Joon; Baek, Jehyun; Kim, Young-Hak; Kim, Namkug; Yang, Dong Hyun

    2016-07-01

    Quantifying turbulence velocity fluctuation is important because it indicates the fluid energy dissipation of the blood flow, which is closely related to the pressure drop along the blood vessel. This study aims to evaluate the effects of scan parameters and the target vessel size of 4D phase-contrast (PC)-MRI on quantification of turbulent kinetic energy (TKE). Comprehensive 4D PC-MRI measurements with various velocity-encoding (VENC), echo time (TE), and voxel size values were carried out to estimate TKE distribution in stenotic flow. The total TKE (TKEsum), maximum TKE (TKEmax), and background noise level (TKEnoise) were compared for each scan parameter. The feasibility of TKE estimation in small vessels was also investigated. Results show that the optimum VENC for stenotic flow with a peak velocity of 125cm/s was 70cm/s. Higher VENC values overestimated the TKEsum by up to six-fold due to increased TKEnoise, whereas lower VENC values (30cm/s) underestimated it by 57.1%. TE and voxel size did not significantly influence the TKEsum and TKEnoise, although the TKEmax significantly increased as the voxel size increased. TKE quantification in small-sized vessels (3-5-mm diameter) was feasible unless high-velocity turbulence caused severe phase dispersion in the reference image. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. 4D dose calculation and delivery with interplay effects between respiratory motion and uniform scanning proton beam

    NASA Astrophysics Data System (ADS)

    Zhao, Qingya

    2011-12-01

    Proton radiotherapy has advantages to deliver accurate high conformal radiation dose to the tumor while sparing the surrounding healthy tissue and critical structures. However, the treatment effectiveness is degraded greatly due to patient free breathing during treatment delivery. Motion compensation for proton radiotherapy is especially challenging as proton beam is more sensitive to the density change along the beam path. Tumor respiratory motion during treatment delivery will affect the proton dose distribution and the selection of optimized parameters for treatment planning, which has not been fully addressed yet in the existing approaches for proton dose calculation. The purpose of this dissertation is to develop an approach for more accurate dose delivery to a moving tumor in proton radiotherapy, i.e., 4D proton dose calculation and delivery, for the uniform scanning proton beam. A three-step approach has been carried out to achieve this goal. First, a solution for the proton output factor calculation which will convert the prescribed dose to machine deliverable monitor unit for proton dose delivery has been proposed and implemented. The novel sector integration method is accurate and time saving, which considers the various beam scanning patterns and treatment field parameters, such as aperture shape, aperture size, measuring position, beam range, and beam modulation. Second, tumor respiratory motion behavior has been statistically characterized and the results have been applied to advanced image guided radiation treatment. Different statistical analysis and correlation discovery approaches have been investigated. The internal / external motion correlation patterns have been simulated, analyzed, and applied in a new hybrid gated treatment to improve the target coverage. Third, a dose calculation method has been developed for 4D proton treatment planning which integrates the interplay effects of tumor respiratory motion patterns and proton beam delivery

  1. 2nd to 4th digit ratio (2D:4D) and number of sex partners: evidence for effects of prenatal testosterone in men.

    PubMed

    Hönekopp, Johannes; Voracek, Martin; Manning, John T

    2006-01-01

    The number of sexual partners per individual (NSP) is an important component of sexual behaviour. Here, we report two studies concerning the relationship between a probable negative correlate of prenatal testosterone, the ratio of the length of 2nd and 4th digits (2D:4D), and NSP in men. The right hand 2D:4D ratio appears to be more strongly related to prenatal testosterone than does the left hand. Accordingly we found: (a) in a sample of 99 German heterosexual male undergraduates right hand 2D:4D (but not left hand 2D:4D) was significantly negatively associated with reported lifetime NSP. The relationship between NSP and 2D:4D was independent of free testosterone, but free testosterone also showed a weak positive association with NSP (b) in a sample of 79 heterosexual and 95 homosexual Austrian men we found a significant negative association between right hand 2D:4D (but not left hand 2D:4D) and reported NSP in past year for heterosexual but not for homosexual men. The association in heterosexuals was independent of age, years of education, occupation and relationship status. We conclude that male NSP is likely to be influenced by the long-term organisational effects of prenatal testosterone. The relationship between NSP and 2D:4D appears to be confined to heterosexual men.

  2. [Effect of atrazine, linuron and 2, 4-D amine on various biological properties of a soil sample. I - Field trial].

    PubMed

    Frioni, L

    1981-01-01

    Herbicides have a considerable influence on soil microorganisms and soil biochemistry. These influences are likely to be reflected in soil fertility and plant growth. The effects of atrazine, linuron and 2,4-D amine were studied on soil microflora in a field trial with sorghum in Río Cuarto, Argentina. Atrazine and linuron were applied before sowing and before emergency, and 2-4,-D amine as post-emergence herbicide. Dehydrogenase activity with TTC (tri-Cl-phenyl-tetrazolium) as electron acceptor, nitrogen mineralization by the steam-distillation method (ammonia and nitrate) and enumerations of cellulose-decomposing microorganisms and dinitrogen fixing genus Azotobacter on selective mediums, were studied. The dehydrogenase activity did not show conclusive effects of herbicide action. The small differences at 20 and 71 days after sowing, fluctuated around the control value. The nitrogen mineralization was also barely affected by treatments. At 20 days after sowing, all plots with herbicide accumulated less mineral nitrogen than the control, but only those treated atrazine before emergence (2 kg/ha) differed significantly (5%). At 71 days a small stimulation of nitrification by linuron was observed. These differences disappeared at the end of the trial (3 1/2 months). The microbial population of cellulose decomposers was very sensitive to herbicides. This restriction seems to depend on unfavorable food conditions for these microorganisms in a soil without weeds, or it is due to enzyme inhibition by pesticides. This group was inhibited by all treatments in the same manner at flowering time. The nitrogen fixing Azotobacter, which is stimulated in the rhizosphere of grasses, was not affected by these chemicals.

  3. Effect of respiratory motion on lung counting efficiency using a 4D NURBS-based cardio-torso (NCAT) phantom.

    PubMed

    Tremblay, Marilyn; Kramer, Gary H; Capello, Kevin; Segars, Paul

    2014-12-01

    The Human Monitoring Laboratory (Canada) has looked at parameters (lung volume, lung deposition pattern, etc.) that can affect the counting efficiency of its lung counting system. The calibration of the system is performed using the Lawrence Livermore National Laboratory (LLNL) torso phantom; however, the effect of respiratory motion cannot be accounted for using these phantoms. When measuring an internal deposition in the lungs of a subject, respiration causes a change in the volume of the lungs and the thoracic cavity and introduces a variable distance between the lungs and the detectors. These changes may have an impact on the counting efficiency and may need to be considered during a measurement. In this study, the HML has simulated the respiration motion using a 4D non-uniform rational b-spline (NURBS)-based Cardiac-Torso (NCAT) phantom and determined the impact of that motion on the counting efficiency of their lung counting system during measurement. The respiratory motion was simulated by a 16 timeframe cycled 4D NURBS-based NCAT phantom developed at the Department of Biomedical Engineering and Radiology, University of North Carolina. The counting efficiency of the four germanium detectors comprising the HML lung counting system was obtained using MCNPX version 2.6E for photon energies between 17 and 1,000 keV. The amount of uncertainty due to the breathing motion was estimated by looking at the efficiency bias, which was highest at low photon energies as expected due to attenuation and geometry effects. Also, to reduce the influence of the detectors' positioning, an array was calculated by adding the individual detector tallies for a given energy and timeframe. For photon energies of 40 keV and higher, the array efficiency bias showed an underestimation of about 5%. If compared to other parameters already studied by the HML, this value demonstrates the insignificant impact of the breathing motion.

  4. Tax and Semaphorin 4D Released from Lymphocytes Infected with Human Lymphotropic Virus Type 1 and Their Effect on Neurite Growth.

    PubMed

    Quintremil, Sebastián; Alberti, Carolina; Rivera, Matías; Medina, Fernando; Puente, Javier; Cartier, Luis; Ramírez, Eugenio; Tanaka, Yuetsu; Valenzuela, M Antonieta

    2016-01-01

    Human lymphotropic virus type 1 (HTLV-1) is a retrovirus causing HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), a neurodegenerative central nervous system (CNS) axonopathy. This virus mainly infects CD4(+) T lymphocytes without evidence of neuronal infection. Viral Tax, secreted from infected lymphocytes infiltrated in the CNS, is proposed to alter intracellular pathways related to axonal cytoskeleton dynamics, producing neurological damage. Previous reports showed a higher proteolytic release of soluble Semaphorin 4D (sSEMA-4D) from CD4(+) T cells infected with HTLV-1. Soluble SEMA-4D binds to its receptor Plexin-B1, activating axonal growth collapse pathways in the CNS. In the current study, an increase was found in both SEMA-4D in CD4(+) T cells and sSEMA-4D released to the culture medium of peripheral blood mononuclear cells (PBMCs) from HAM/TSP patients compared to asymptomatic carriers and healthy donors. After a 16-h culture, infected PBMCs showed significantly higher levels of CRMP-2 phosphorylated at Ser(522). The effect was blocked either with anti-Tax or anti-SEMA-4D antibodies. The interaction of Tax and sSEMA-4D was found in secreted medium of PBMCs in patients, which might be associated with a leading role of Tax with the SEMA-4D-Plexin-B1 signaling pathway. In infected PBMCs, the migratory response after transwell assay showed that sSEMA-4D responding cells were CD4(+)Tax(+) T cells with a high CRMP-2 pSer(522) content. In the present study, the participation of Tax-sSEMA-4D in the reduction in neurite growth in PC12 cells produced by MT2 (HTLV-1-infected cell line) culture medium was observed. These results lead to the participation of plexins in the reported effects of infected lymphocytes on neuronal cells.

  5. The effect of 2,4-dichlorophenoxy acid (2,4-D) on peanut when applied during vegetative growth stages

    USDA-ARS?s Scientific Manuscript database

    The development of 2,4-D-resistant cotton and soybean cultivars has created great concern about the potential off-target movement of 2,4-D onto sensitive broadleaf crops. Peanut is often grown in close proximity to cotton and soybean. Therefore, field studies were conducted during 2012 and 2013 at...

  6. Evaluation of Fractional Regional Ventilation Using 4D-CT and Effects of Breathing Maneuvers on Ventilation

    SciTech Connect

    Mistry, Nilesh N.; Diwanji, Tejan; Shi, Xiutao; Pokharel, Sabin; Feigenberg, Steven; Scharf, Steven M.; D'Souza, Warren D.

    2013-11-15

    Purpose: Current implementations of methods based on Hounsfield units to evaluate regional lung ventilation do not directly incorporate tissue-based mass changes that occur over the respiratory cycle. To overcome this, we developed a 4-dimensional computed tomography (4D-CT)-based technique to evaluate fractional regional ventilation (FRV) that uses an individualized ratio of tidal volume to end-expiratory lung volume for each voxel. We further evaluated the effect of different breathing maneuvers on regional ventilation. The results from this work will help elucidate the relationship between global and regional lung function. Methods and Materials: Eight patients underwent 3 sets of 4D-CT scans during 1 session using free-breathing, audiovisual guidance, and active breathing control. FRV was estimated using a density-based algorithm with mass correction. Internal validation between global and regional ventilation was performed by use of the imaging data collected during the use of active breathing control. The impact of breathing maneuvers on FRV was evaluated comparing the tidal volume from 3 breathing methods. Results: Internal validation through comparison between the global and regional changes in ventilation revealed a strong linear correlation (slope of 1.01, R{sup 2} of 0.97) between the measured global lung volume and the regional lung volume calculated by use of the “mass corrected” FRV. A linear relationship was established between the tidal volume measured with the automated breathing control system and FRV based on 4D-CT imaging. Consistently larger breathing volumes were observed when coached breathing techniques were used. Conclusions: The technique presented improves density-based evaluation of lung ventilation and establishes a link between global and regional lung ventilation volumes. Furthermore, the results obtained are comparable with those of other techniques of functional evaluation such as spirometry and hyperpolarized-gas magnetic

  7. A radiobiological analysis of the effect of 3D versus 4D image-based planning in lung cancer radiotherapy.

    PubMed

    Roland, Teboh; Mavroidis, Panayiotis; Gutierrez, Alonso; Goytia, Virginia; Papanikolaou, Niko

    2009-09-21

    Dose distributions generated on a static anatomy may differ significantly from those delivered to temporally varying anatomy such as for abdominal and thoracic tumors, due largely in part to the unavoidable organ motion and deformation effects stemming from respiration. In this work, the degree of such variation for three treatment techniques, namely static conventional, gating and target tracking radiotherapy, was investigated. The actual delivered dose was approximated by planning all the phases of a 4DCT image set. Data from six (n = 6) previously treated lung cancer patients were used for this study with tumor motion ranging from 2 to 10 mm. Complete radiobiological analyses were performed to assess the clinical significance of the observed discrepancies between the 3D and 4DCT image-based dose distributions. Using the complication-free tumor control probability (P+) objective, we observed small differences in P+ between the 3D and 4DCT image-based plans (<2.0% difference on average) for the gating and static conventional regimens and higher differences in P+ (4.0% on average) for the tracking regimen. Furthermore, we observed, as a general trend, that the 3D plan underestimated the P+ values. While it is not possible to draw any general conclusions from a small patient cohort, our results suggest that there exists a patient population in which 4D planning does not provide any additional benefits beyond that afforded by 3D planning for static conventional or gated radiotherapy. This statement is consistent with previous studies based on physical dosimetric evaluations only. The higher differences observed with the tracking technique suggest that individual patient plans should be evaluated on a case-by-case basis to assess if 3D or 4D imaging is appropriate for the tracking technique.

  8. Oscillator strengths and branching fractions of 4d75p-4d75s Rh II transitions

    NASA Astrophysics Data System (ADS)

    Bouazza, Safa

    2017-01-01

    This work reports semi-empirical determination of oscillator strengths, transition probabilities and branching fractions for Rh II 4d75p-4d75s transitions in a wide wavelength range. The angular coefficients of the transition matrix, beforehand obtained in pure SL coupling with help of Racah algebra are transformed into intermediate coupling using eigenvector amplitudes of these two configuration levels determined for this purpose; The transition integral was treated as free parameter in the least squares fit to experimental oscillator strength (gf) values found in literature. The extracted value: <4d75s|r1|4d75p> =2.7426 ± 0.0007 is slightly smaller than that computed by means of ab-initio method. Subsequently to oscillator strength evaluations, transition probabilities and branching fractions were deduced and compared to those obtained experimentally or through another approach like pseudo-relativistic Hartree-Fock model including core-polarization effects.

  9. What a couple of dimensions can do for you: Comparative developmental studies using 4D microscopy--examples from tardigrade development.

    PubMed

    Hejnol, Andreas; Schnabel, Ralf

    2006-04-01

    The development of an organism consists of processes occurring in space and time. To analyze this 4-dimensional development in embryogenesis, an appropriate method should be chosen. We present here a sophisticated method, 4D microscopy (3D time-lapse microscopy), initially developed to analyze the cell lineage of wild-type and mutant embryos of the nematode Caenorhabditis elegans. Our method records the entire development of an embryo and allows detailed analyses of events such as cleavage, cell migration, cell death (apoptosis), and cell differentiation during development. The 4D microscopy system has 3 main parts: a motorized microscope, trigger software, and a database that facilitates the analysis of recordings. Adopting the 4D microscopy technique for uses beyond the analysis of C. elegans makes it possible to discern the cell lineage of other small embryos. Our method fills a gap in the study of the development of diverse organisms that are impossible to observe with fluorescent labeling techniques using single blastomeres. The use of this technique to investigate the development of organisms such as tardigrades, acoelomorphs, rotifers, and gastrotrichs provides fresh insight into the evolution of developmental processes and the phylogenetic relationships between such taxa. Using tardigrade development as an example, we demonstrate that the use of 4D microscopy can reveal new characters and corroborate or disapprove old characters. We discuss the results in the light of recent phylogenetic hypotheses regarding the Arthropoda and their probable sister group, the Cycloneuralia, which together form the Ecdysozoa.

  10. 4-D photoacoustic tomography.

    PubMed

    Xiang, Liangzhong; Wang, Bo; Ji, Lijun; Jiang, Huabei

    2013-01-01

    Photoacoustic tomography (PAT) offers three-dimensional (3D) structural and functional imaging of living biological tissue with label-free, optical absorption contrast. These attributes lend PAT imaging to a wide variety of applications in clinical medicine and preclinical research. Despite advances in live animal imaging with PAT, there is still a need for 3D imaging at centimeter depths in real-time. We report the development of four dimensional (4D) PAT, which integrates time resolutions with 3D spatial resolution, obtained using spherical arrays of ultrasonic detectors. The 4D PAT technique generates motion pictures of imaged tissue, enabling real time tracking of dynamic physiological and pathological processes at hundred micrometer-millisecond resolutions. The 4D PAT technique is used here to image needle-based drug delivery and pharmacokinetics. We also use this technique to monitor 1) fast hemodynamic changes during inter-ictal epileptic seizures and 2) temperature variations during tumor thermal therapy.

  11. 4-D Photoacoustic Tomography

    NASA Astrophysics Data System (ADS)

    Xiang, Liangzhong; Wang, Bo; Ji, Lijun; Jiang, Huabei

    2013-01-01

    Photoacoustic tomography (PAT) offers three-dimensional (3D) structural and functional imaging of living biological tissue with label-free, optical absorption contrast. These attributes lend PAT imaging to a wide variety of applications in clinical medicine and preclinical research. Despite advances in live animal imaging with PAT, there is still a need for 3D imaging at centimeter depths in real-time. We report the development of four dimensional (4D) PAT, which integrates time resolutions with 3D spatial resolution, obtained using spherical arrays of ultrasonic detectors. The 4D PAT technique generates motion pictures of imaged tissue, enabling real time tracking of dynamic physiological and pathological processes at hundred micrometer-millisecond resolutions. The 4D PAT technique is used here to image needle-based drug delivery and pharmacokinetics. We also use this technique to monitor 1) fast hemodynamic changes during inter-ictal epileptic seizures and 2) temperature variations during tumor thermal therapy.

  12. Beneficial effects of the melanocortin analogue Nle4-D-Phe7-α-MSH in acne vulgaris.

    PubMed

    Böhm, M; Ehrchen, J; Luger, T A

    2014-01-01

    α-Melanocyte-stimulating hormone (α-MSH) is a melanocortin peptide that increases skin pigmentation during ultraviolet light-mediated tanning. As α-MSH has been shown to possess anti-inflammatory effects, we assessed the clinical potential of a superpotent α-MSH analogue, afamelanotide (Nle(4)-D-Phe(7)-α-MSH), in patients with acne vulgaris, the most common inflammatory skin disorder. Afamelanotide (16 mg) was given in a phase II open-label pilot study subcutaneously as a sustained-release resorbable implant formulation to 3 patients with mild-to-moderate facial acne vulgaris. Evaluation included lesion count, adverse effects and patient-reported outcome. Monitoring of laboratory parameters included differential blood counts, electrolytes, urine analysis, and liver and kidney function tests. Skin melanin density was measured by reflectance spectrophotometry. The total number as well as the number of inflammatory acne lesions declined in all patients 56 days after the first injection of afamelanotide. Life quality as measured by Dermatology Life Quality Index likewise improved in all 3 patients 56 days after the first injection of afamelanotide. There were no adverse effects except mild and short-term fatigue in one patient. All patients experienced increased pigmentation especially on the face. Clinically relevant changes in laboratory parameters were not detected. Afamelanotide appears to have anti-inflammatory effects in patients with mild-to-moderate acne vulgaris. Future trials are needed to confirm the anti-inflammatory action of this melanocortin analogue in patients with acne vulgaris. © 2012 The Authors. Journal of the European Academy of Dermatology and Venereology © 2012 European Academy of Dermatology and Venereology.

  13. Assessing eco-toxicological effects of industrial 2,4-D acid iso-octylester herbicide on rat pancreas and liver.

    PubMed

    Kalipci, E; Ozdemir, C; Oztas, H

    2013-05-01

    We studied the eco-toxic and carcinogenic effects of a commonly used 2,4-D acid iso-octylester herbicide on rat liver and pancreas. The rats in Group 1 were fed a standard feed and the rats in Group 2 were fed with standard feed to which was added 200 mg/kg/day 2,4-D acid iso-octylester for 16 weeks. Azaserine, 30 mg/kg/body weight, was injected into rats of Groups 3 and 4 to investigate the effects of 2,4-D acid iso-octylester on the development of neoplasms. After feeding the rats with neoplasms in Group 4 with food including 200 mg/kg/day 2,4-D acid iso-octylester for 16 weeks, an autopsy was carried out on all animals. We found that 2,4-D acid iso-octylester caused the formation of atypical cell foci (ACF) in the pancreata and livers of rats. ACF that were formed experimentally by exposure to azaserine had increased diameter, volume and number of atypical cell foci/mm(2) and mm(3) after exposure to 2,4-D acid iso-octylester. Our observations indicated that this herbicide potentially is a cancer initiator.

  14. Endurance running and digit ratio (2D:4D): implications for fetal testosterone effects on running speed and vascular health.

    PubMed

    Manning, John T; Morris, Laura; Caswell, Noreen

    2007-01-01

    There is anatomical and physiological evidence that endurance running (ER), i.e., running one or more kilometers using aerobic metabolism, originated early in the evolution of Homo, and the consequences of early selection for ER may be important in modern Homo. Here we examine ER performance in competitive ER. ER is sex dependent such that men tend to run faster than women, and the influence of sex on ER suggests that it may be modified by testosterone (T). It is shown that a putative proxy for prenatal T, the ratio of the length of the 2nd and 4th digits (2D:4D), is correlated with ER. Thus performance in training for ER was associated with high prenatal T, as measured by low 2D:4D, in both men and women. In cross-country races from 1 to 4 miles, 2D:4D explained about 25% of the variance in both male and female ER. Therefore, speed in ER was dependent on a proxy for prenatal T. 2D:4D correlates with performance in sport and exercises, which test a mix of strength and fitness, but the associations are in general quite weak with 2D:4D accounting for less than 10% of the variance in performance. Our finding that 2D:4D explains about 25% of the variance in ER suggests that prenatal T is important in determining efficiency in aerobic exercise. Early populations of Homo may have been strongly selected for ER and high prenatal T. The implications of this for patterns of predisposition to cardiovascular disease in modern Homo are discussed. Copyright 2007 Wiley-Liss, Inc.

  15. A meta-analysis on the effects of 2,4-D and dicamba drift on soybean and cotton

    USDA-ARS?s Scientific Manuscript database

    Commercial introduction of cultivars of soybean and cotton genetically modified with resistance to the synthetic-auxin herbicides dicamba and 2,4-D will allow these compounds to be used with greater flexibility but may expose susceptible soybean and cotton cultivars to non-target herbicide drift. Fr...

  16. Evaluation of the combined effects of target size, respiratory motion and background activity on 3D and 4D PET/CT images

    NASA Astrophysics Data System (ADS)

    Park, Sang-June; Ionascu, Dan; Killoran, Joseph; Mamede, Marcelo; Gerbaudo, Victor H.; Chin, Lee; Berbeco, Ross

    2008-07-01

    Gated (4D) PET/CT has the potential to greatly improve the accuracy of radiotherapy at treatment sites where internal organ motion is significant. However, the best methodology for applying 4D-PET/CT to target definition is not currently well established. With the goal of better understanding how to best apply 4D information to radiotherapy, initial studies were performed to investigate the effect of target size, respiratory motion and target-to-background activity concentration ratio (TBR) on 3D (ungated) and 4D PET images. Using a PET/CT scanner with 4D or gating capability, a full 3D-PET scan corrected with a 3D attenuation map from 3D-CT scan and a respiratory gated (4D) PET scan corrected with corresponding attenuation maps from 4D-CT were performed by imaging spherical targets (0.5-26.5 mL) filled with 18F-FDG in a dynamic thorax phantom and NEMA IEC body phantom at different TBRs (infinite, 8 and 4). To simulate respiratory motion, the phantoms were driven sinusoidally in the superior-inferior direction with amplitudes of 0, 1 and 2 cm and a period of 4.5 s. Recovery coefficients were determined on PET images. In addition, gating methods using different numbers of gating bins (1-20 bins) were evaluated with image noise and temporal resolution. For evaluation, volume recovery coefficient, signal-to-noise ratio and contrast-to-noise ratio were calculated as a function of the number of gating bins. Moreover, the optimum thresholds which give accurate moving target volumes were obtained for 3D and 4D images. The partial volume effect and signal loss in the 3D-PET images due to the limited PET resolution and the respiratory motion, respectively were measured. The results show that signal loss depends on both the amplitude and pattern of respiratory motion. However, the 4D-PET successfully recovers most of the loss induced by the respiratory motion. The 5-bin gating method gives the best temporal resolution with acceptable image noise. The results based on the 4D

  17. RNA interference-mediated phosphodiesterase 4D splice variants knock-down in the prefrontal cortex produces antidepressant-like and cognition-enhancing effects

    PubMed Central

    Wang, Zhen-Zhen; Zhang, Yi; Liu, Yan-Qin; Zhao, Nan; Zhang, You-Zhi; Yuan, Li; An, Lei; Li, Jing; Wang, Xiao-Yun; Qin, Juan-Juan; Wilson, Steven P; O'Donnell, James M; Zhang, Han-Ting; Li, Yun-Feng

    2013-01-01

    Background and Purpose Phosphodiesterase 4 (PDE4) inhibitors produce potent antidepressant-like and cognition-enhancing effects. However, their clinical utility is limited by the major side effect of emesis, which appears to be PDE4 isoform-specific. Although PDE4D subtype plays the pivotal role in these therapeutic profiles, it is also the primary subtype responsible for emesis. Therefore, the aim of present research was to investigate whether long-form PDE4D variants mediate antidepressant-like and cognition-enhancing effects, but are irrespective with emesis. Experimental Approach In mice microinfused with lentiviral vectors that contained shRNA-mir hairpin structure targeting long-form PDE4Ds into bilateral prefrontal cortices, the tail-suspension and forced-swim tests were used to measure antidepressant-like effects; novel object recognition and Morris water-maze tasks were used to determine cognition-enhancing effects. The emetic potential was assessed by alpha2 adrenergic receptor-mediated anaesthesia, a surrogate measure of emesis. Intracellular cAMP signalling was analysed by time-resolved FRET immunoassay and Western-blot. Dendritic complexity was assessed by Golgi staining. Key Results Microinfusions of lentiviral PDE4D-shRNA down-regulated PDE4D4 and PDE4D5, and imitated the antidepressant-like and cognition-enhancing effects of the prototypical PDE4 inhibitor rolipram. The behavioural effects were related to dendritic complexity and mediated by the increased cAMP signalling. In addition, these effects were not enhanced in the presence of rolipram. Finally, while rolipram shortened the duration of combined anaesthesia, RNA interference-mediated PDE4D knock-down in the prefrontal cortex did not. Conclusion and Implications These data suggest that long-form PDE4Ds, at least PDE4D4 and PDE4D5, may be the promising targets for the development of PDE4 variant-selective inhibitors as the new pharmacotherapies for depressive disorders and neurodegenerative

  18. SU-F-303-13: Initial Evaluation of Four Dimensional Diffusion- Weighted MRI (4D-DWI) and Its Effect On Apparent Diffusion Coefficient (ADC) Measurement

    SciTech Connect

    Liu, Y; Yin, F; Czito, B; Bashir, M; Palta, M; Cai, J; Zhong, X; Dale, B

    2015-06-15

    Purpose: Diffusion-weighted imaging(DWI) has been shown to have superior tumor-to-tissue contrast for cancer detection.This study aims at developing and evaluating a four dimensional DWI(4D-DWI) technique using retrospective sorting method for imaging respiratory motion for radiotherapy planning,and evaluate its effect on Apparent Diffusion Coefficient(ADC) measurement. Materials/Methods: Image acquisition was performed by repeatedly imaging a volume of interest using a multi-slice single-shot 2D-DWI sequence in the axial planes and cine MRI(served as reference) using FIESTA sequence.Each 2D-DWI image were acquired in xyz-diffusion-directions with a high b-value(b=500s/mm2).The respiratory motion was simultaneously recorded using bellows.Retrospective sorting was applied in each direction to reconstruct 4D-DWI.The technique was evaluated using a computer simulated 4D-digital human phantom(XCAT),a motion phantom and a healthy volunteer under an IRB-approved study.Motion trajectories of regions-of-interests(ROI) were extracted from 4D-DWI and compared with reference.The mean motion trajectory amplitude differences(D) between the two was calculated.To quantitatively analyze the motion artifacts,XCAT were controlled to simulate regular motion and the motions of 10 liver cancer patients.4D-DWI,free-breathing DWI(FB- DWI) were reconstructed.Tumor volume difference(VD) of each phase of 4D-DWI and FB-DWI from the input static tumor were calculated.Furthermore, ADC was measured for each phase of 4D-DWI and FB-DWI data,and mean tumor ADC values(M-ADC) were calculated.Mean M-ADC over all 4D-DWI phases was compared with M-ADC calculated from FB-DWI. Results: 4D-DWI of XCAT,the motion phantom and the healthy volunteer demonstrated the respiratory motion clearly.ROI D values were 1.9mm,1.7mm and 2.0mm,respectively.For motion artifacts analysis,XCAT 4D-DWI images show much less motion artifacts compare to FB-DWI.Mean VD for 4D-WDI and FB-DWI were 8.5±1.4% and 108±15

  19. Effect of GA3 and 2,4-D foliar application on the anatomy of date palm (Phoenix dactylifera L.) seedling leaf

    PubMed Central

    Doaigey, Abdullah R.; Al-Whaibi, M.H.; Siddiqui, M.H.; Al Sahli, A.A.; El-Zaidy, M.E.

    2012-01-01

    Two concentrations (10-5M and 10-3M) of both GA3 and 2,4-D were used as foliar spray to evaluate the response of date palm (Phoenix dactylifera L.) cv. Khedri seedlings. They affected some of the anatomical characteristics of the first leaf emerging after the beginning of the spray. The high concentration of GA3 increased the size of the midrib and its vascular bundle numbers. Both low and high concentrations of 2,4-D inhibited the formation of the midrib. 2,4-D in both low and high concentrations decreased the number of vessels in both protoxylem and metaxylem and also decreased their diameters, where as GA3 in low and high concentrations have less effect on the number of vessels and its diameters. GA3 in high concentration increased the number of vascular bundles in 1mm long of the leaf blade, while 2,4-D in low and high concentrations decreased their numbers. 10-3M of 2,4-D increased the size and layers of special hypodermal cells. PMID:23961229

  20. Effect of GA3 and 2,4-D foliar application on the anatomy of date palm (Phoenix dactylifera L.) seedling leaf.

    PubMed

    Doaigey, Abdullah R; Al-Whaibi, M H; Siddiqui, M H; Al Sahli, A A; El-Zaidy, M E

    2013-04-01

    Two concentrations (10-5M and 10-3M) of both GA3 and 2,4-D were used as foliar spray to evaluate the response of date palm (Phoenix dactylifera L.) cv. Khedri seedlings. They affected some of the anatomical characteristics of the first leaf emerging after the beginning of the spray. The high concentration of GA3 increased the size of the midrib and its vascular bundle numbers. Both low and high concentrations of 2,4-D inhibited the formation of the midrib. 2,4-D in both low and high concentrations decreased the number of vessels in both protoxylem and metaxylem and also decreased their diameters, where as GA3 in low and high concentrations have less effect on the number of vessels and its diameters. GA3 in high concentration increased the number of vascular bundles in 1mm long of the leaf blade, while 2,4-D in low and high concentrations decreased their numbers. 10-3M of 2,4-D increased the size and layers of special hypodermal cells.

  1. SU-F-BRD-01: A Novel 4D Robust Optimization Mitigates Interplay Effect in Intensity-Modulated Proton Therapy for Lung Cancer

    SciTech Connect

    Liu, W; Shen, J; Stoker, J; Bues, M; Schild, S; Wong, W; Chang, J; Liao, Z; Wen, Z; Sahoo, N; Herman, M; Mohan, R

    2015-06-15

    Purpose: To compare the impact of interplay effect on 3D and 4D robustly optimized intensity-modulated proton therapy (IMPT) plans to treat lung cancer. Methods: Two IMPT plans were created for 11 non-small-cell-lung-cancer cases with 6–14 mm spots. 3D robust optimization generated plans on average CTs with the internal gross tumor volume density overridden to deliver 66 CGyE in 33 fractions to the internal target volume (ITV). 4D robust optimization generated plans on 4D CTs with the delivery of prescribed dose to the clinical target volume (CTV). In 4D optimization, the CTV of individual 4D CT phases received non-uniform doses to achieve a uniform cumulative dose. Dose evaluation software was developed to model time-dependent spot delivery to incorporate interplay effect with randomized starting phases of each field per fraction. Patient anatomy voxels were mapped from phase to phase via deformable image registration to score doses. Indices from dose-volume histograms were used to compare target coverage, dose homogeneity, and normal-tissue sparing. DVH indices were compared using Wilcoxon test. Results: Given the presence of interplay effect, 4D robust optimization produced IMPT plans with better target coverage and homogeneity, but slightly worse normal tissue sparing compared to 3D robust optimization (unit: Gy) [D95% ITV: 63.5 vs 62.0 (p=0.014), D5% - D95% ITV: 6.2 vs 7.3 (p=0.37), D1% spinal cord: 29.0 vs 29.5 (p=0.52), Dmean total lung: 14.8 vs 14.5 (p=0.12), D33% esophagus: 33.6 vs 33.1 (p=0.28)]. The improvement of target coverage (D95%,4D – D95%,3D) was related to the ratio RMA3/(TVx10−4), with RMA and TV being respiratory motion amplitude (RMA) and tumor volume (TV), respectively. Peak benefit was observed at ratios between 2 and 10. This corresponds to 125 – 625 cm3 TV with 0.5-cm RMA. Conclusion: 4D optimization produced more interplay-effect-resistant plans compared to 3D optimization. It is most effective when respiratory motion is modest

  2. Effect of 2,4-D herbicide (2,4-dichlorophenoxyacetic acid) on oxygen consumption and ammonium excretion of juveniles of Geophagus brasiliensis (Quoy & Gaimard, 1824) (Osteichthyes, Cichlidae).

    PubMed

    Barbieri, Edison

    2009-01-01

    Fish form important fisheries and aquaculture resources worldwide. In Brazil, pearl eartheater (Geophagus brasiliensis) is an important commercially exploited species and is an ideal animal for studying the impairment caused by the effects of herbicides that are often detected in the aquatic environment. The main purpose of the present study was to detect the acute toxicity of 2,4-dichlorophenoxyacetic acid (2,4-D) to G. brasiliensis and investigate its effects on oxygen consumption, ammonium excretion, and the neutral red retention time assay to estimate effects at the cellular level. Such investigations have not been carried out before with this species. First, the acute toxicity of 2,4-D to G. brasiliensis in terms of the 24-, 48-, 72-, and 96-h medium lethal concentration (LC(50)) was calculated to be 45.95, 32.49, 28.28, and 15.16 mg/l, respectively. Furthermore, it was found that exposure of fish to 40 mg/l 2,4-D caused reduction in oxygen consumption and ammonium excretion of 59% and 85%, respectively, in relation to the controls. Mean neutral red retention time assay was significantly lower in comparison with control for organisms exposed to 1, 5, 10, and 40 mg/l 2,4-D. However, the effects at the cellular level were progressive, suggesting that the fish are not able to recover from such increasing effects.

  3. Toxic and genotoxic effects of the 2,4-dichlorophenoxyacetic acid (2,4-D)-based herbicide on the Neotropical fish Cnesterodon decemmaculatus.

    PubMed

    Ruiz de Arcaute, C; Soloneski, S; Larramendy, M L

    2016-06-01

    Acute toxicity and genotoxicity of the 54.8% 2,4-D-based commercial herbicide DMA® were assayed on Cnesterodon decemmaculatus (Pisces, Poeciliidae). Whereas lethal effect was used as the end point for mortality, frequency of micronuclei (MNs), other nuclear abnormalities and primary DNA damage evaluated by the single cell gel electrophoresis (SCGE) assay were employed as end points for genotoxicity. Mortality studies demonstrated an LC50 96 h value of 1008 mg/L (range, 929-1070) of 2,4-D. Behavioral changes, e.g., gathering at the bottom of the aquarium, slowness in motion, slow reaction and abnormal swimming were observed. Exposure to 2,4-D within the 252-756 mg/L range increased the frequency of MNs in fish exposed for both 48 and 96 h. Whereas blebbed nuclei were induced in treatments lasting for 48 and 96 h, notched nuclei were only induced in fish exposed for 96 h. Regardless of both concentration and exposure time, 2,4-D did not induce lobed nuclei and binucleated erythrocytes. In addition, we found that exposure to 2,4-D within the 252-756 mg/L range increased the genetic damage index in treatments lasting for either 48 and 96 h. The results represent the first experimental evidence of the lethal and several sublethal effects, including behavioral alterations and two genotoxic properties namely the induction of MNs and primary DNA strand breaks, exerted by 2,4-D on an endemic organism as C. decemmaculatus.

  4. 4d Spectra from BPS Quiver Dualities

    NASA Astrophysics Data System (ADS)

    Espahbodi, Sam

    We attack the question of BPS occupancy in a wide class of 4d N = 2 quantum field theories. We first review the Seiberg-Witten approach to finding the low energy Wilsonian effective action actions of such theories. In particular, we analyze the case of Gaiotto theories, which provide a large number of non-trivial examples in a unified framework. We then turn to understanding the massive BPS spectrum of such theories, and in particular their relation to BPS quivers. We present a purely 4d characterization of BPS quivers, and explain how a quiver's representation theory encodes the solution to the BPS occupancy problem. Next, we derive a so called mutation method, based on exploiting quiver dualities, to solve the quiver's representation theory. This method makes previously intractable calculations nearly trivial in many examples. As a particular highlight, we apply our methods to understand strongly coupled chambers in ADE SYM gauge theories with matter. Following this, we turn to the general story of quivers for theories of the Gaiotto class. We present a geometric approach to attaining quivers for the rank 2 theories, leading to a very elegant solution which includes a specification of quiver superpotentials. Finally, we solve these theories by an unrelated method based on gauging flavor symmetries in their various dual weakly coupled Lagrangian descriptions. After seeing that this method agrees in the rank 2 case, we will apply our new approach to the case of rank n.

  5. Evaluation of Aortic Stenosis Severity using 4D Flow Jet Shear Layer Detection for the Measurement of Valve Effective Orifice Area

    PubMed Central

    Garcia, Julio; Markl, Michael; Schnell, Susanne; Allen, Bradley; Entezari, Pegah; Mahadevia, Riti; Malaisrie, S Chris; Pibarot, Philippe; Carr, James; Barker, Alex J

    2014-01-01

    Aims The objective of this study was to evaluate the potential of 4D flow MRI to assess valve effective orifice area (EOA) in patients with aortic stenosis as determined by the jet shear layer detection (JSLD) method. Methods and Results An in-vitro stenosis phantom was used for validation and in-vivo imaging was performed in 10 healthy controls and 40 patients with aortic stenosis. EOA was calculated by the JSLD method using standard 2D phase contrast MRI (PC-MRI) and 4D flow MRI measurements (EOAJSLD-2D and EOAJSLD-4D, respectively). As a reference standard, the continuity equation was used to calculate EOA (EOACE) with the 2D PC-MRI velocity field and compared to the EOAJSLD measurements. The in-vitro results exhibited excellent agreement between flow theory (EOA=0.78 cm2) and experimental measurement (EOAJSLD-4D=0.78±0.01 cm2) for peak velocities ranging from 0.9 to 3.7 m/s. In-vivo results showed good correlation and agreement between EOAJSLD-2D and EOACE (r=0.91, p<0.001; bias: −0.01±0.38cm2; agreement limits: 0.75 to −0.77cm2), and between EOAJSLD-4D and EOACE (r=0.95, p<0.001; bias: −0.09±0.26cm2; limits: 0.43 to −0.62cm2). Conclusion This study demonstrates the feasibility of measuring EOAJSLD using 4D flow MRI. The technique allows for optimization of the EOA measurement position by visualizing the 3D vena contracta, and avoids potential sources of EOACE measurement variability. PMID:24865143

  6. Digit ratio (2D:4D) and salivary testosterone, oestradiol and cortisol levels under challenge: Evidence for prenatal effects on adult endocrine responses.

    PubMed

    Crewther, Blair; Cook, Christian; Kilduff, Liam; Manning, John

    2015-08-01

    Digit ratio (2D:4D) is a marker for prenatal sex steroids and a correlate of sporting performance. This association may exist because low 2D:4D is linked to high prenatal levels of testosterone (T) and low oestrogens (E). It was recently suggested that low 2D:4D, and particularly low right-left 2D:4D (or Dr-l), is a marker for T changes in response to physical and aggressive challenges. If correct, this link may in part explain the association between 2D:4D and sports performance. We tested this hypothesis in adults. Three experimental treatments were completed using a randomised, cross-over design; (i) cycle sprints plus an aggressive video (S+V), (ii) aggressive video plus cycle sprints (V+S), and (iii) a control session. 24 healthy adults (12 men and 12 women). Salivary T, oestradiol (E2) and cortisol (C) levels were measured on six occasions across each session and pooled for analysis. The S+V treatment was associated with a rise in T and C levels, and Dr-l was significantly and negatively correlated with T and E2 with these effects confined to men. The right 2D:4D and Dr-l were also negatively correlated with the T/C ratio and Dr-l negatively related to the E2/C ratio in men during the S+V treatment. We suggest that the hormonal responses to a challenge are programmed by prenatal levels of T and E with possible links to sporting performance in adulthood. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  7. 4D volcano gravimetry

    USGS Publications Warehouse

    Battaglia, Maurizio; Gottsmann, J.; Carbone, D.; Fernandez, J.

    2008-01-01

    Time-dependent gravimetric measurements can detect subsurface processes long before magma flow leads to earthquakes or other eruption precursors. The ability of gravity measurements to detect subsurface mass flow is greatly enhanced if gravity measurements are analyzed and modeled with ground-deformation data. Obtaining the maximum information from microgravity studies requires careful evaluation of the layout of network benchmarks, the gravity environmental signal, and the coupling between gravity changes and crustal deformation. When changes in the system under study are fast (hours to weeks), as in hydrothermal systems and restless volcanoes, continuous gravity observations at selected sites can help to capture many details of the dynamics of the intrusive sources. Despite the instrumental effects, mainly caused by atmospheric temperature, results from monitoring at Mt. Etna volcano show that continuous measurements are a powerful tool for monitoring and studying volcanoes.Several analytical and numerical mathematical models can beused to fit gravity and deformation data. Analytical models offer a closed-form description of the volcanic source. In principle, this allows one to readily infer the relative importance of the source parameters. In active volcanic sites such as Long Valley caldera (California, U.S.A.) and Campi Flegrei (Italy), careful use of analytical models and high-quality data sets has produced good results. However, the simplifications that make analytical models tractable might result in misleading volcanological inter-pretations, particularly when the real crust surrounding the source is far from the homogeneous/ isotropic assumption. Using numerical models allows consideration of more realistic descriptions of the sources and of the crust where they are located (e.g., vertical and lateral mechanical discontinuities, complex source geometries, and topography). Applications at Teide volcano (Tenerife) and Campi Flegrei demonstrate the

  8. Effects of oral administration of 2,4-dichlorophenoxyacetic acid (2,4-D) on reproductive parameters in male Wistar rats.

    PubMed

    Marouani, Neila; Tebourbi, Olfa; Cherif, Donia; Hallegue, Dorsaf; Yacoubi, Mohamed Tahar; Sakly, Mohsen; Benkhalifa, Moncef; Ben Rhouma, Khemais

    2017-01-01

    The 2,4-dichlorophenoxyacetic acid (2,4-D) is used worldwide in agriculture as a selective herbicide. It has been shown to produce a wide range of adverse effects on the health of both animals and humans from embryotoxicity and teratogenicity to neurotoxicity. In the present study, we have examined the effect of 2,4-D on male reproductive function of rats. Male Wistar rats received daily by force-feeding 100 or 200 mg of 2,4-D/kg body weight for 30 consecutive days. Rats exposed to 100 and 200 mg of 2,4-D/kg showed a significant decrease in body weights only after 24 days of treatment and in relative weights of testis, seminal vesicles and prostate at killing day, when compared with controls. Moreover, a decrease in testosterone and an increase in FSH and LH serum levels were detected in treated rats. Besides, exposure to this herbicide induced pronounced testicular histological alterations with enlarged intracellular spaces, tissue loosening and dramatic loss of gametes in the lumen of the seminiferous tubules. In addition, a decreased motility and a number of epididymal spermatozoa with an increased sperm abnormality rate were found in treated rats in comparison with control. With the highest dose, histological observations of seminal vesicles indicated a considerable decrease of secretions in the lumen, a thinness of the muscle layer surrounding the epithelium with branched mucosal crypts and reduced luminal space. In prostate, the heights of the cells decreased while acinar lumen were enlarged and they lost the typical invaginations. Our results suggest that a subacute treatment of 2,4-D promotes reproductive system toxicity.

  9. The effects of sublethal levels of 2,4-dichlorophenoxyacetic acid herbicide (2,4-D) on feeding behaviors of the crayfish O. rusticus.

    PubMed

    Browne, Amanda M; Moore, Paul A

    2014-08-01

    The widespread use of herbicides across the globe has increased the probability of synthetic chemicals entering freshwater habitats. On entering aquatic habitats, these chemicals target and disrupt both physiological and behavioral functioning in various aquatic organisms. Herbicides, such as 2,4-dichlorophenoxyacetic acid (2,4-D), can have negative impacts on chemoreception because these receptor cells are in direct contact with water-soluble chemicals in the environment. Studies focusing on lethal concentration (LC50) levels may understate the impact of herbicides within aquatic habitats because damage to the chemoreceptors can result in modified behaviors or lack of appropriate responses to environmental or social cues. The purpose of this experiment was to determine whether exposure to sublethal levels of 2,4-D alters the foraging behaviors of crayfish Orconectes rusticus. We hypothesized that crayfish exposed to greater concentrations of 2,4-D would be less successful in locating food or on locating food would consume smaller amounts possibly due to an inability to recognize the food odors in the contaminated waters. Crayfish were exposed to three sublethal levels of 2,4-D for 96 h and placed into a Y-maze system with a fish gelatin food source placed randomly in the right or left arm. Average walking speed, average time spent in the correct arm, and percent consumption were analyzed. Our data show that crayfish were impaired in their ability to forage effectively. These inabilities to locate and consume adequate amounts of food could result in lower body weights and decreased fitness in populations of crayfish exposed to 2,4-D in natural habitats.

  10. From 4d Yang-Mills to 2d ℂℙN - 1 model: IR problem and confinement at weak coupling

    NASA Astrophysics Data System (ADS)

    Yamazaki, Masahito; Yonekura, Kazuya

    2017-07-01

    We study four-dimensional SU( N) Yang-Mills theory on R× T^3=R× {S}_A^1× {S}_B^1× {S}_C^1 , with a twisted boundary condition by a ℤ N center symmetry imposed on S B 1 × S C 1 . This setup has no IR zero modes and hence is free from IR divergences which could spoil trans-series expansion for physical observables. Moreover, we show that the center symmetry is preserved at weak coupling regime. This is shown by first reducing the theory on T^2={S}_A× {S}_B , to connect the model to the two-dimensional ℂℙ N- 1-model. Then, we prove that the twisted boundary condition by the center symmetry for the Yang-Mills is reduced to the twisted boundary condition by the ℤ N global symmetry of ℂℙ N- 1. There are N classical vacua, and fractional instantons connecting those N vacua dynamically restore the center symmetry. We also point out the presence of singularities on the Borel plane which depend on the shape of the compactification manifold, and comment on its implications.

  11. Multivariate genetic analyses of the 2D:4D ratio: examining the effects of hand and measurement technique in data from 757 twin families.

    PubMed

    Medland, Sarah E; Loehlin, John C

    2008-06-01

    The ratio of the lengths of the second to fourth digits of the hand (2D:4D) is a sexually dimorphic trait that has been proposed as a measure of prenatal testosterone exposure and a putative correlate of a variety of later behavioral and physiological outcomes including personality, fitness and sexual orientation. We present analyses of 2D:4D ratios collected from twins (1413 individuals) and their nontwin siblings (328 individuals) from 757 families. In this sample 2D:4D was measured from photocopies using digital calipers, and for a subset of participants, computer-aided measurement. Multivariate modeling of the left- and right-hand measurements revealed significant genetic and environmental covariation between hands. The two methods yielded very similar results, and the majority of variance was explained by factors shared by both measurement methods. Neither common environmental nor dominant genetic effects were found, and the covariation between siblings could be accounted for by additive genetic effects accounting for 80% and 71% of the variance for the left and right hands, respectively. There was no evidence of sex differences in the total variance, nor in the magnitude or source of genetic and environmental influences, suggesting that X-linked effects (such as the previously identified association with the Androgen receptor) are likely to be small. However, there were also nonshared environmental effects specific to each hand, which, in addition to measurement error, may in part explain why some studies within in the literature find effects for the 2D:4D ratio of one hand but not the other.

  12. Effect of surface coordination on 2,4-D sorption by kaolinite from methanol/water mixture.

    PubMed

    Kim, Minhee; Hyun, Seunghun

    2014-05-01

    The application of the cosolvency sorption model to predict the sorption of carboxylic acids in cosolvent systems was found to be problematic. The cause of the discrepancy was investigated by analyzing the solubility (Sm) and sorption (Km, linear sorption coefficient) of the pesticide 2,4-dichlorophenoxyacetic acid (2,4-D) on metal-saturated kaolinites, as a function of methanol volume fraction (fc) and apparent solution pH. The possible formation of a coordination compound during the hydrophilic interaction of 2,4-dichlorophenoxyacetate in methanol-water mixture was identified using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. The Sm of 2,4-dichlorophenoxyacetate increased with increasing fc. Thus, the shift of activity of solute occurred in the liquid phase was not significant for determining the cause of the positive Km-fc relationship. However, Km value of 2,4-dichlorophenoxyacetate on the metal-saturated kaolinite increased log-linearly with fc. The ATR-FTIR results on surface coordination of 2,4-dichlorophenoxyacetate on the metal-saturated kaolinite surface showed that bidentate coordination is more likely to occur instead of a bridging coordination with increasing fc. Therefore, it can be reasonably concluded that the positive Km-fc relationship is due to the charge-related hydrophilic interaction through bidentate coordination of 2,4-dichlorophenoxyacetate, and it increases with increasing positive charge density on the kaolinites, as a function of fc.

  13. 2,4-D abatement from groundwater samples by photo-Fenton processes at circumneutral pH using naturally iron present. Effect of inorganic ions.

    PubMed

    Gutiérrez-Zapata, Héctor M; Rojas, Karen L; Sanabria, Janeth; Rengifo-Herrera, Julián Andrés

    2017-03-01

    This study evaluated, at laboratory scale, if the using iron naturally present (0.3 mg L(-1)) and adding 10 mg L(-1) of hydrogen peroxide was effective to remove 24.3 mgL(-1) of 2,4-dichlorophenoxyacetic acid (2,4-D) from groundwater samples by simulated solar irradiation (global intensity = 300 W m(-2)). Under these conditions, the degradation of 2,4-D reached 75.2 % and the apparition of its main oxidation byproduct 2,4-dichlorophenol (DCP) was observed. On the other hand, pH exhibited an increasing from 7.0 to 8.3 during the experiment. Experiments using Milli-Q water at pH 7.0, iron, and H2O2 concentrations of 0.3 and 10 mg L(-1), respectively, were carried out in order to study the effect of ions such as carbonate species, phosphate, and fluoride in typical concentrations often found in groundwater. Ion concentrations were combined by using a factorial experimental design 2(3). Results showed that carbonates and fluoride did not produce a detrimental effect on the 2,4-D degradation, while phosphate inhibited the process. In this case, the pH increased also from 7.0 to 7.95 and 8.99. Effect of parameters such as pH, iron concentration, and hydrogen peroxide concentration on the 2,4-D degradation by the photo-Fenton process in groundwater was evaluated by using a factorial experimental design 2(3). Results showed that the pH was the main parameter affecting the process. This study shows for the first time that using the photo-Fenton process at circumneutral pH and iron naturally present seems to be a promising process to remove pesticides from groundwater.

  14. Digit ratio (2D:4D) and psychopathic traits moderate the effect of exogenous testosterone on socio-cognitive processes in men.

    PubMed

    Carré, Justin M; Ortiz, Triana L; Labine, Brandy; Moreau, Benjamin J P; Viding, Essi; Neumann, Craig S; Goldfarb, Bernard

    2015-12-01

    Recent evidence suggests that testosterone is negatively correlated with empathic processes in both men and women. Also, administration of testosterone to young women impairs socio-cognitive performance as assessed using the "Reading the Mind in the Eyes Task", especially among those exposed to elevated testosterone concentrations prenatally. However, the extent to which testosterone plays a similar causal role in socio-cognitive abilities in men is currently unknown. Here, using a crossover, double-blind, placebo-controlled, within-subject design, we investigated the extent to which a single administration of testosterone to healthy young men (N=30) would impair socio-cognitive abilities assessed using the "Reading the Mind in the Eyes Task" (RMET). Also, we investigated whether individual differences in 2D:4D ratio and psychopathic traits would moderate the effect of testosterone on task performance. Results indicated that testosterone administration on its own did not impair RMET performance. However, variability in both 2D:4D ratio and psychopathic traits moderated the effect of testosterone on task performance. Specifically, testosterone impaired RMET performance among individuals with relatively low (i.e., masculinized) 2D:4D ratio and among individuals scoring relatively low on the interpersonal/affective facet (i.e., Factor 1) of psychopathy. Our findings highlight the importance of considering theoretically- and empirically-based individual difference factors when attempting to characterize the neuroendocrine mechanisms underlying socio-cognitive processes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Effects of prenatal exposure to 2,4-D/2,4,5-T mixture on postnatal changes in rat brain glutamate, GABA protein, and nucleic acid levels

    SciTech Connect

    Mohammad, F.K.; Omer, V.E.V.

    1988-02-01

    The opportunity of maternal exposure to various chemicals in the work place and the general environments have increased, and the fetus and neonate may be at greater risk than the adult. However, the embryotoxic and teratogenic effects of the chlorinated phenoxy herbicides 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), the main chemicals in Agent Orange, are well documented only in laboratory animals. The brain of the developing fetus is vulnerable to the toxic effects of the phenoxy herbicides which readily cross the placental barrier and distribute into fetal tissues, including brain. Although the neurochemical basis for the behavioral teratogenicity of the phenoxy herbicides is not know, it was recently reported that non-teratogenic doses of a 1:1 mixture of 2,4-D and 2,4,5-T delayed the ontogeny of dopamine and serotonin in the brain of the developing rate. This communication provides further descriptive information about the ontogeny of rat brain nucleic acid, protein, glutamate and ..gamma..-aminobutyrate (GABA) following in utero exposure to non-teratogenic levels of a 1:1 mixture of 2,4-D/2,4,5-T.

  16. The sublethal effects of (2,4-Dichlorophenoxy) acetic acid (2,4-D) on narrow-clawed crayfish (Astacus leptodactylus Eschscholtz, 1823).

    PubMed

    Benli, A Çağlan Karasu; Şahin, Duygu; Sarıkaya, Rabia; Memmi, Burcu Koçak; Dinçel, Aylin Sepici

    2016-12-01

    2,4-D is a widely used phenoxy herbicide, potentially toxic to humans and biota. The objective of the present study was to reveal short term sublethal effects of 2,4-D on narrow-clawed freshwater crayfish (Astacus leptodactylus Eschscholtz, 1823), based on histology, total haemocyte counts, selected haemolymph parameters, and oxidative stress parameters. In the laboratory conditions crayfish specimens were exposed to 9 mg L-1 of 2,4-D for one week. Experiments were conducted under semi-static conditions in 20 L-capacity aquaria where 10 freshwater crayfish were stocked per aquarium. Exposure (experimental) and control groups were used and the experiments were repeated two times. No mortality and behavioural changes were recorded during the experiments. Total haemocyte counts decreased significantly, while haemolymph glucose levels increased (P<0.05), when compared to the control group. Haemolymph levels of calcium, chloride, sodium, potassium, magnesium, total protein, and lactate did not change. Exposure resulted with increased levels of malondialdehyde (MDA) only in hepatopancreas. However, results of gill FOX assay showed a significant decrease in oxidative stress parameters (P<0.05). MDA levels of gill and abdominal muscle tissues and FOX levels of hepatopancreas and abdominal muscle tissues did not change when compared to the control group. Significant histopathological alterations were observed both in hepatopancreas (multifocal deformations in tubule lumen) and gill tissue (melanisation of gill lamella). Exposure of crayfish even to a sublethal concentration of 2,4-D alters histopathology and lipid peroxidation due to stress. Biomarkers studied here seem to be useful for the assessment of adverse/toxic effects of pesticides on non-target, indicator aquatic organisms.

  17. 2,4-D adsorption to biochars: effect of preparation conditions on equilibrium adsorption capacity and comparison with commercial activated carbon literature data.

    PubMed

    Kearns, J P; Wellborn, L S; Summers, R S; Knappe, D R U

    2014-10-01

    Batch isotherm experiments were conducted with chars to study adsorption of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). Chars generated from corncobs, bamboo and wood chips in a laboratory pyrolyzer at 400-700 °C were compared with traditional kiln charcoals collected from villages in S/SE Asia and with activated carbons (ACs). 2,4-D uptake by laboratory chars obtained from bamboo and wood chips after 14 h of pyrolysis at 700 °C, from wood chips after 96 h of pyrolysis at 600 °C, and one of the field-collected chars (basudha) was comparable to ACs. H:C and O:C ratios declined with pyrolysis temperature and duration while surface area increased to >500 m(2)/g. Increasing pyrolysis intensity by increasing temperature and/or duration of heating was found to positively influence adsorption capacity yield (mg(2,4-D/g(feedstock))) over the range of conditions studied. Economic analysis showed that high temperature chars can be a cost-effective alternative to ACs for water treatment applications.

  18. Digit (2D:4D) ratio is associated with muscle mass (MM) and strength (MS) in older adults: possible effect of in utero androgen exposure.

    PubMed

    Halil, Meltem; Gurel, Esin Ileri; Kuyumcu, Mehmet Emin; Karaismailoglu, Serkan; Yesil, Yusuf; Ozturk, Zeynel Abidin; Yavuz, Burcu Balam; Cankurtaran, Mustafa; Ariogul, Servet

    2013-01-01

    Decline in MM and MS with aging, defined as sarcopenia, is related with physical disability, poor quality of life and death. Its mechanisms are not fully understood. Testosterone increases muscle protein synthesis. However, the effects of in utero androgen exposure to MM and MS in older adults have not been studied. In utero androgen exposure is inversely related with 2D:4D ratio. The aim of this study was to investigate the relationship between 2D:4D ratio as an indicator of in utero androgen exposure and MM and MS in elderly patients. A total of 151 older adults were included. Calf-circumference (CC) and skeletal muscle mass index (SMI) were used for the assessment of MM and hand grip strength for the assessment of MS. Mean age ± SD of the patients was 73.72 ± 6.23. Fifty-two (34.4%) of patients were male, 99 (65.6%) were female. Right and left 2D:4D were significantly and negatively correlated with hand grip strength (r=-0.365, p=0.018 and r=-0.434, p=0.005, respectively), CC (r=-0.422, p=0.002 and r=-0.459, p=0.001, respectively) and SMI (r=-0.354, p=0.018 and r=-0.348, p=0.022, respectively) in men. In women, right and left 2D:4D were significantly and negatively correlated with hand grip strength (r=-0.252, p=0.022 and r=-0.234, p=0.033, respectively), CC (r=-0.229, p=0.024 and r=-0.302, p=0.003, respectively) and SMI (r=-0.382, p<0.001 and r=-0.431, p<0.001, respectively). In this study, we found that 2D:4D ratio was significantly and negatively correlated with parameters depicting MM and MS which may suggest the possible role of in utero androgen exposure in the development of MM and MS loss in the elderly. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  19. Single-Event Effect Testing of the Cree C4D40120D Commercial 1200V Silicon Carbide Schottky Diode

    NASA Technical Reports Server (NTRS)

    Lauenstein, J.-M.; Casey, M. C.; Wilcox, E. P.; Kim, Hak; Topper, A. D.

    2014-01-01

    This study was undertaken to determine the single event effect (SEE) susceptibility of the commercial silicon carbide 1200V Schottky diode manufactured by Cree, Inc. Heavy-ion testing was conducted at the Texas A&M University Cyclotron Single Event Effects Test Facility (TAMU). Its purpose was to evaluate this device as a candidate for use in the Solar-Electric Propulsion flight project.

  20. Effect of MLC tracking latency on conformal volumetric modulated arc therapy (VMAT) plans in 4D stereotactic lung treatment

    PubMed Central

    Bedford, James L.; Fast, Martin F.; Nill, Simeon; McDonald, Fiona M.A.; Ahmed, Merina; Hansen, Vibeke N.; Oelfke, Uwe

    2015-01-01

    Background and purpose The latency of a multileaf collimator (MLC) tracking system used to overcome respiratory motion causes misalignment of the treatment beam with respect to the gross tumour volume, which may result in reduced target coverage. This study investigates the magnitude of this effect. Material and methods Simulated superior–inferior breathing motion was used to construct histograms of isocentre offset with respect to the gross tumour volume (GTV) for a variety of tracking latencies. Dose distributions for conformal volumetric modulated arc therapy (VMAT) arcs were then calculated at a range of offsets and summed according to these displacement histograms. The results were verified by delivering the plans to a Delta4 phantom on a motion platform. Results In the absence of an internal target margin, a tracking latency of 150 ms reduces the GTV D95% by approximately 2%. With a margin of 2 mm, the same drop in dose occurs for a tracking latency of 450 ms. Lung V13Gy is unaffected by a range of latencies. These results are supported by the phantom measurements. Conclusions Assuming that internal motion can be modelled by a rigid translation of the patient, MLC tracking of conformal VMAT can be effectively accomplished in the absence of an internal target margin for substantial breathing motion (4 s period and 20 mm peak–peak amplitude) so long as the system latency is less than 150 ms. PMID:26277856

  1. Effectiveness and feasibility of utilizing E4D technology as a teaching tool in a preclinical dental education environment.

    PubMed

    Callan, Richard S; Palladino, Christie L; Furness, Alan R; Bundy, Emily L; Ange, Brittany L

    2014-10-01

    Recent efforts have been directed towards utilizing CAD/CAM technology in the education of future dentists. The purpose of this pilot study was to investigate the feasibility of implementing CAD/CAM technology in instruction on preparing a tooth for restoration. Students at one dental school were assigned access to CAD/CAM technology vs. traditional preparation methods in a randomized, crossover design. In a convenience sample of a second-year class, seventy-six of the seventy-nine students volunteered to participate, for a response rate of 96 percent. Two analyses were performed on this pilot data: a primary effectiveness analysis comparing students' competency exam scores by intervention group (intention-to-treat analysis) and a secondary efficacy analysis comparing competency exam scores among students who reported using CAD/CAM versus those who did not. The effectiveness analysis showed no difference in outcomes by intervention group assignment. While student survey results indicated interest in utilizing the technology, the actual utilization rate was much less than one might anticipate, yielding a sample size that limited statistical power. The secondary analysis demonstrated higher mean competency exam scores for students reporting use of CAD/CAM compared to those who did not use the technology, but these results did not reach statistical significance (p=0.075). Prior research has investigated the efficacy of CAD/CAM in a controlled educational trial, but this study adds to the literature by investigating student use of CAD/CAM in a real-world, self-study fashion. Further studies should investigate ways in which to increase student utilization of CAD/CAM and whether or not increased utilization, with a larger sample size, would yield significant outcomes.

  2. Coupling effects in optical metamaterials.

    PubMed

    Liu, Na; Giessen, Harald

    2010-12-17

    Metamaterials have become one of the hottest fields of photonics since the pioneering work of John Pendry on negative refractive index, invisibility cloaking, and perfect lensing. Three-dimensional metamaterials are required for practical applications. In these materials, coupling effects between individual constituents play a dominant role for the optical and electronic properties. Metamaterials can show both electric and magnetic responses at optical frequencies. Thus, electric as well as magnetic dipolar and higher-order multipolar coupling is the essential mechanism. Depending on the structural composition, both longitudinal and transverse coupling occur. The intricate interplay between different coupling effects in a plasmon hybridization picture provides a useful tool to intuitively understand the evolution from molecule-like states to solid-state-like bands.

  3. Memory-enhancing effects of GEBR-32a, a new PDE4D inhibitor holding promise for the treatment of Alzheimer's disease.

    PubMed

    Ricciarelli, Roberta; Brullo, Chiara; Prickaerts, Jos; Arancio, Ottavio; Villa, Carla; Rebosio, Claudia; Calcagno, Elisa; Balbi, Matilde; van Hagen, Britt T J; Argyrousi, Elentina K; Zhang, Hong; Pronzato, Maria Adelaide; Bruno, Olga; Fedele, Ernesto

    2017-04-12

    Memory loss characterizes several neurodegenerative disorders, including Alzheimer's disease (AD). Inhibition of type 4 phosphodiesterase (PDE4) and elevation of cyclic adenosine monophosphate (cAMP) has emerged as a promising therapeutic approach to treat cognitive deficits. However, PDE4 exists in several isoforms and pan inhibitors cannot be used in humans due to severe emesis. Here, we present GEBR-32a, a new PDE4D full inhibitor that has been characterized both in vitro and in vivo using biochemical, electrophysiological and behavioural analyses. GEBR-32a efficiently enhances cAMP in neuronal cultures and hippocampal slices. In vivo pharmacokinetic analysis shows that GEBR-32a is rapidly distributed within the central nervous system with a very favourable brain/blood ratio. Specific behavioural tests (object location and Y-maze continuous alternation tasks) demonstrate that this PDE4D inhibitor is able to enhance memory in AD transgenic mice and concomitantly rescues their hippocampal long-term potentiation deficit. Of great relevance, our preliminary toxicological analysis indicates that GEBR-32a is not cytotoxic and genotoxic, and does not seem to possess emetic-like side effects. In conclusion, GEBR-32a could represent a very promising cognitive-enhancing drug with a great potential for the treatment of Alzheimer's disease.

  4. Poster — Thur Eve — 30: 4D VMAT dose calculation methodology to investigate the interplay effect: experimental validation using TrueBeam Developer Mode and Gafchromic film

    SciTech Connect

    Teke, T; Milette, MP; Huang, V; Thomas, SD

    2014-08-15

    The interplay effect between the tumor motion and the radiation beam modulation during a VMAT treatment delivery alters the delivered dose distribution from the planned one. This work present and validate a method to accurately calculate the dose distribution in 4D taking into account the tumor motion, the field modulation and the treatment starting phase. A QUASAR™ respiratory motion phantom was 4D scanned with motion amplitude of 3 cm and with a 3 second period. A static scan was also acquired with the lung insert and the tumor contained in it centered. A VMAT plan with a 6XFFF beam was created on the averaged CT and delivered on a Varian TrueBeam and the trajectory log file was saved. From the trajectory log file 10 VMAT plans (one for each breathing phase) and a developer mode XML file were created. For the 10 VMAT plans, the tumor motion was modeled by moving the isocentre on the static scan, the plans were re-calculated and summed in the treatment planning system. In the developer mode, the tumor motion was simulated by moving the couch dynamically during the treatment. Gafchromic films were placed in the QUASAR phantom static and irradiated using the developer mode. Different treatment starting phase were investigated (no phase shift, maximum inhalation and maximum exhalation). Calculated and measured isodose lines and profiles are in very good agreement. For each starting phase, the dose distribution exhibit significant differences but are accurately calculated with the methodology presented in this work.

  5. Evaluation of the effect of respiratory and anatomical variables on a Fourier technique for markerless, self-sorted 4D-CBCT

    NASA Astrophysics Data System (ADS)

    Vergalasova, I.; Cai, J.; Giles, W.; Segars, W. P.; Yin, F. F.

    2013-10-01

    A novel technique based on Fourier transform theory has been developed that directly extracts respiratory information from projections without the use of external surrogates. While the feasibility has been demonstrated with three patients, a more extensive validation is necessary. Therefore, the purpose of this work is to investigate the effects of a variety of respiratory and anatomical scenarios on the performance of the technique with the 4D digital extended cardiac torso phantom. FT-phase and FT-magnitude methods were each applied to identify peak-inspiration projections and quantitatively compared to the gold standard of visual identification. Both methods proved to be robust across the studied scenarios with average differences in respiratory phase <10% and percentage of projections assigned within 10% of the gold standard >90%, when incorporating minor modifications to region-of-interest (ROI) selection and/or low-frequency location for select cases of DA and lung percentage in the field of view of the projection. Nevertheless, in the instance where one method initially faltered, the other method prevailed and successfully identified peak-inspiration projections. This is promising because it suggests that the two methods provide complementary information to each other. To ensure appropriate clinical adaptation of markerless, self-sorted four-dimensional cone-beam CT (4D-CBCT), perhaps an optimal integration of the two methods can be developed.

  6. Effects of Oblique Extension and Inherited Structure Geometry on Transfer Zone Development in Continental Rifts: A 4D Analogue Modeling Approach

    NASA Astrophysics Data System (ADS)

    Zwaan, Frank; Schreurs, Guido

    2015-04-01

    INTRODUCTION Inherited structures in the crust form weak zones along which deformation will focus during rifting. Along-strike connection of rift segments may occur along transfer zones, as observed in East Africa. Previous studies have focused on numerical and analog modeling of transfer zones (e.g. Acocella et al., 1999, Allken et al., 2012). We elaborate upon those by investigating the effects of 1) oblique extension and 2) the geometry of linked and non-linked inherited structures on the development of transfer zones. A further improvement is the use of X-ray Computer Tomography (CT) for detailed internal analysis. METHODS The experimental set-up (see Schreurs & Colleta, 1998) contains two sidewalls with a base of compressed foam and plexiglass bars stacked in between. Decompressing this base results in distributed deformation of the overlying model materials. Deforming the model laterally with a mobile base plate produces the strike-slip components for oblique extension. Divergence velocities are in the order of 5 mm/h, translating to ca. 5 mm/Ma in nature, and 1 cm represents 10 km. A 2 cm thick layer of viscous silicone represents the ductile lower crust and a 2 cm quartz sand layer the brittle upper crust. Inherited structures are created with thin lines of silicon laid down on top of the basal silicone layer. Several models were run in a CT-scanner to reveal the 3D evolution of internal structures with time, hence 4D. RESULTS Localization of deformation along the pre-defined structures works well. The models show that the structural style changes with extension obliquity, from wide rift structures to narrower rifts with internal oblique-slip and finally strike-slip structures. Furthermore, rift offset is an important parameter influencing the occurrence of linkage: increasing rift offset decreases linkage as previously observed by Allken et al. (2012). However, increasing divergence obliquity promotes transfer zone formation, as does the presence of rift

  7. Finger Length Ratio (2D:4D) in Central India and an Attempt to Verify Fraternal Birth Order Effect: A Population Based Cross-Sectional Study.

    PubMed

    Maitra, Arjun; Maitra, Chaitali; Jha, Dilip Kumar; Biswas, Rakesh

    2016-12-01

    A normal physiology of a human being is not mere a series of functions occurring with specific intensities and timing. There are lot of factors that may change the normal physiological activity within normal limits. Finger length ratio is one of the markers of intrauterine androgen exposure and it is debated and contradicted by many authors. Digit ratio varies among the ethnicities. Many Indian studies show that there is considerable difference in finger length ratio in different population. Data regarding Central India was not found on extensive search. To find out the finger length ratio and explore the birth order effect on finger length ratio among the first two successive born in the said population. We conducted a survey on 1500 volunteer persons (800 male and 700 female) over two years of time. We measured the length of the index finger (2D) and ring finger (4D) of both the hands and asked about their birth order history to find out the digit ratio for Central India population and any existing correlation of the same with birth order. T Test and Analysis of Variance (ANOVA) were used for the measure of significance and difference among the groups. The p< 0.05 was considered to be significant. Our study reports that, study population mean for right hand 2D:4D ratio was 0.976 (SD±0.031) and for left hand it was found to be 0.969 (SD±0.035). For males, mean finger length ratio for right hand was 0.967 (SD±0.033) and 0.963 (SD±0.037) for left hand. In females the mean Finger length ratio was 0.982 (SD±0.027) for right hand and 0.974 (SD±0.034) for the left hand respectively. Finger length ratio was found to be significantly less (p=0.03) in males for right hand. No significant (p=0.24) difference was observed for left hand. When assessed fraternal birth order effect among the eldest, second born with elder brother and second born with elder sister groups, no significant (p>0.05) variation for finger length ratio of right and left hands observed in both

  8. Finger Length Ratio (2D:4D) in Central India and an Attempt to Verify Fraternal Birth Order Effect: A Population Based Cross-Sectional Study

    PubMed Central

    Maitra, Chaitali; Jha, Dilip Kumar; Biswas, Rakesh

    2016-01-01

    Introduction A normal physiology of a human being is not mere a series of functions occurring with specific intensities and timing. There are lot of factors that may change the normal physiological activity within normal limits. Finger length ratio is one of the markers of intrauterine androgen exposure and it is debated and contradicted by many authors. Digit ratio varies among the ethnicities. Many Indian studies show that there is considerable difference in finger length ratio in different population. Data regarding Central India was not found on extensive search. Aim To find out the finger length ratio and explore the birth order effect on finger length ratio among the first two successive born in the said population. Materials and Methods We conducted a survey on 1500 volunteer persons (800 male and 700 female) over two years of time. We measured the length of the index finger (2D) and ring finger (4D) of both the hands and asked about their birth order history to find out the digit ratio for Central India population and any existing correlation of the same with birth order. T Test and Analysis of Variance (ANOVA) were used for the measure of significance and difference among the groups. The p< 0.05 was considered to be significant. Results Our study reports that, study population mean for right hand 2D:4D ratio was 0.976 (SD±0.031) and for left hand it was found to be 0.969 (SD±0.035). For males, mean finger length ratio for right hand was 0.967 (SD±0.033) and 0.963 (SD±0.037) for left hand. In females the mean Finger length ratio was 0.982 (SD±0.027) for right hand and 0.974 (SD±0.034) for the left hand respectively. Finger length ratio was found to be significantly less (p=0.03) in males for right hand. No significant (p=0.24) difference was observed for left hand. When assessed fraternal birth order effect among the eldest, second born with elder brother and second born with elder sister groups, no significant (p>0.05) variation for finger length

  9. Basic nanosystems of early 4d and 5d transition metals: Electronic properties and the effect of spin-orbit interaction

    NASA Astrophysics Data System (ADS)

    Bala, Anu; Nautiyal, Tashi; Auluck, Sushil

    2008-07-01

    There are various possibilities for the structure as well as for the growth of nanosystems, particularly of nanowires. The ultimate one-dimensional material—linear chains—are difficult to exploit for applications due to their transient nature. Nonetheless these are a good prototype for studying one-dimensional materials and project the kind of behavior one may expect from ultrathin nanowires. Likewise monolayers are the ultimate two-dimensional materials and their study is helpful in understanding the behavior of two-dimensional materials. We present a theoretical study on basic nanosystems—linear chains and monolayers—of the 4d (Y, Zr, Nb, Mo, and Tc) and 5d (Hf, Ta, W, and Re) transition metals of groups 3-7 by means of an all-electron density functional approach. We have explored all kinds of magnetic configurations: nonmagnetic, ferromagnetic, and antiferromagnetic, by (i) inclusion and (ii) omission of spin-orbit interaction. We find that though this interaction has a marginal effect on nanosystems of 4d transition metals, its impact becomes stronger with lowering of dimensionality. Further it has a significant effect on properties of nanosystems of 5d transition metals as well as those of bulk. It is interesting to note that the monolayers of 5d transition metals seem reluctant to order magnetically despite the general tendency of nanosystems of 4d transition metals and linear chains of 5d transition metals to woo magnetic ordering. The nanosystems with preference for antiferromagnetic ordering are found to be stable at larger nearest-neighbor distances compared to the ferromagnetic and nonmagnetic phases. Specially, antiferromagnetic monolayers of Nb and Mo are predicted to exhibit larger separations with respect to bulk, a feature observed only for some low-dimensional systems. All the monolayers, except Y, are predicted to have a nonmagnetic state almost degenerate with ferromagnetic or antiferromagnetic state. Therefore suitable substrate

  10. Persistence of 2,4-D and its effects on benthic macroinvertebrates following spring treatment of Eurasian Watermilfoil, Myriophyllum spicatum L. in two lakes in southeastern Wisconsin, USA.

    PubMed

    Harrahy, E A; Edwards, D S; Hedman, C J

    2014-04-01

    The purpose of this study was to determine the persistence of 2,4-dichlorophenoxyacetic acid (2,4-D) applied to two lakes (one mesotrophic and one eutrophic) for the control of Eurasian watermilfoil (EWM), and to determine the impacts of 2,4-D on benthic macroinvertebrates in one of the lakes. One lake was treated with a liquid formulation, and the other with a slow release granular formulation of 2,4-D. Concentrations of 2,4-D in the water column were highest 1 and 2 days post-treatment and declined to below detection limits by 7 and 10 days post-treatment. We observed negative correlations between days post-treatment and taxa richness, and between days post-treatment and abundance of three of 12 taxonomic groups of macroinvertebrates. Lake managers need to balance control of EWM with possible impacts of 2,4-D to nontarget organisms.

  11. Exact Bremsstrahlung and effective couplings

    NASA Astrophysics Data System (ADS)

    Mitev, Vladimir; Pomoni, Elli

    2016-06-01

    We calculate supersymmetric Wilson loops on the ellipsoid for a large class of mathcal{N} = 2 SCFT using the localization formula of Hama and Hosomichi. From them we extract the radiation emitted by an accelerating heavy probe quark as well as the entanglement entropy following the recent works of Lewkowycz-Maldacena and Fiol-Gerchkovitz-Komargodski. Comparing our results with the mathcal{N} = 4 SYM ones, we obtain interpolating functions f ( g 2) such that a given mathcal{N} = 2 SCFT observable is obtained by replacing in the corresponding mathcal{N} = 4 SYM result the coupling constant by f ( g 2). These "exact effective couplings" encode the finite, relative renormalization between the mathcal{N} = 2 and the mathcal{N} = 4 gluon propagator and they interpolate between the weak and the strong coupling. We discuss the range of their applicability.

  12. 4D flow mri post-processing strategies for neuropathologies

    NASA Astrophysics Data System (ADS)

    Schrauben, Eric Mathew

    4D flow MRI allows for the measurement of a dynamic 3D velocity vector field. Blood flow velocities in large vascular territories can be qualitatively visualized with the added benefit of quantitative probing. Within cranial pathologies theorized to have vascular-based contributions or effects, 4D flow MRI provides a unique platform for comprehensive assessment of hemodynamic parameters. Targeted blood flow derived measurements, such as flow rate, pulsatility, retrograde flow, or wall shear stress may provide insight into the onset or characterization of more complex neuropathologies. Therefore, the thorough assessment of each parameter within the context of a given disease has important medical implications. Not surprisingly, the last decade has seen rapid growth in the use of 4D flow MRI. Data acquisition sequences are available to researchers on all major scanner platforms. However, the use has been limited mostly to small research trials. One major reason that has hindered the more widespread use and application in larger clinical trials is the complexity of the post-processing tasks and the lack of adequate tools for these tasks. Post-processing of 4D flow MRI must be semi-automated, fast, user-independent, robust, and reliably consistent for use in a clinical setting, within large patient studies, or across a multicenter trial. Development of proper post-processing methods coupled with systematic investigation in normal and patient populations pushes 4D flow MRI closer to clinical realization while elucidating potential underlying neuropathological origins. Within this framework, the work in this thesis assesses venous flow reproducibility and internal consistency in a healthy population. A preliminary analysis of venous flow parameters in healthy controls and multiple sclerosis patients is performed in a large study employing 4D flow MRI. These studies are performed in the context of the chronic cerebrospinal venous insufficiency hypothesis. Additionally, a

  13. Dosimetric impact of motion in free-breathing and gated lung radiotherapy: A 4D Monte Carlo study of intrafraction and interfraction effects

    PubMed Central

    Seco, Joao; Sharp, Greg C.; Wu, Ziji; Gierga, David; Buettner, Florian; Paganetti, Harald

    2008-01-01

    The purpose of this study was to investigate if interfraction and intrafraction motion in free-breathing and gated lung IMRT can lead to systematic dose differences between 3DCT and 4DCT. Dosimetric effects were studied considering the breathing pattern of three patients monitored during the course of their treatment and an in-house developed 4D Monte Carlo framework. Imaging data were taken in free-breathing and in cine mode for both 3D and 4D acquisition. Treatment planning for IMRT delivery was done based on the free-breathing data with the corvus (North American Scientific, Chatsworth, CA) planning system. The dose distributions as a function of phase in the breathing cycle were combined using deformable image registration. The study focused on (a) assessing the accuracy of the corvus pencil beam algorithm with Monte Carlo dose calculation in the lung, (b) evaluating the dosimetric effect of motion on the individual breathing phases of the respiratory cycle, and (c) assessing intrafraction and interfraction motion effects during free-breathing or gated radiotherapy. The comparison between (a) the planning system and the Monte Carlo system shows that the pencil beam algorithm underestimates the dose in low-density regions, such as lung tissue, and overestimates the dose in high-density regions, such as bone, by 5% or more of the prescribed dose (corresponding to approximately 3–5 Gy for the cases considered). For the patients studied this could have a significant impact on the dose volume histograms for the target structures depending on the margin added to the clinical target volume (CTV) to produce either the planning target (PTV) or internal target volume (ITV). The dose differences between (b) phases in the breathing cycle and the free-breathing case were shown to be negligible for all phases except for the inhale phase, where an underdosage of the tumor by as much as 9.3 Gy relative to the free-breathing was observed. The large difference was due to

  14. Dosimetric impact of motion in free-breathing and gated lung radiotherapy: A 4D Monte Carlo study of intrafraction and interfraction effects

    SciTech Connect

    Seco, Joao; Sharp, Greg C.; Wu Ziji; Gierga, David; Buettner, Florian; Paganetti, Harald

    2008-01-15

    The purpose of this study was to investigate if interfraction and intrafraction motion in free-breathing and gated lung IMRT can lead to systematic dose differences between 3DCT and 4DCT. Dosimetric effects were studied considering the breathing pattern of three patients monitored during the course of their treatment and an in-house developed 4D Monte Carlo framework. Imaging data were taken in free-breathing and in cine mode for both 3D and 4D acquisition. Treatment planning for IMRT delivery was done based on the free-breathing data with the CORVUS (North American Scientific, Chatsworth, CA) planning system. The dose distributions as a function of phase in the breathing cycle were combined using deformable image registration. The study focused on (a) assessing the accuracy of the CORVUS pencil beam algorithm with Monte Carlo dose calculation in the lung, (b) evaluating the dosimetric effect of motion on the individual breathing phases of the respiratory cycle, and (c) assessing intrafraction and interfraction motion effects during free-breathing or gated radiotherapy. The comparison between (a) the planning system and the Monte Carlo system shows that the pencil beam algorithm underestimates the dose in low-density regions, such as lung tissue, and overestimates the dose in high-density regions, such as bone, by 5% or more of the prescribed dose (corresponding to approximately 3-5 Gy for the cases considered). For the patients studied this could have a significant impact on the dose volume histograms for the target structures depending on the margin added to the clinical target volume (CTV) to produce either the planning target (PTV) or internal target volume (ITV). The dose differences between (b) phases in the breathing cycle and the free-breathing case were shown to be negligible for all phases except for the inhale phase, where an underdosage of the tumor by as much as 9.3 Gy relative to the free-breathing was observed. The large difference was due to

  15. Digit ratio (2D:4D), testosterone, cortisol, aggression, personality and hand-grip strength: Evidence for prenatal effects on strength.

    PubMed

    Ribeiro, Evaldo; Neave, Nick; Morais, Rosana Nogueiro; Kilduff, Liam; Taylor, Suzan R; Butovskaya, Marina; Fink, Bernhard; Manning, John T

    2016-09-01

    Digit ratio (2D:4D) is a putative marker for prenatal testosterone and is correlated with performance in many sports. Low 2D:4D has been linked to strength but the evidence is mixed and strength is also influenced by mass, testosterone, and behavioural factors. It has been hypothesised that the 2D:4D-strength correlation may be strongest in challenge conditions when short-term changes occur in steroid hormones. We tested this suggestion in men. We used a cross-over study design with a challenge (an aggressive video of rugby tackles) and control (a blank screen) condition. 89 healthy men. Finger lengths (2nd and 4th for both hands), hand-grip strength (HGS), testosterone (T), cortisol (C), aggression (Buss-Perry Aggression Questionnaire) and personality type (Ten Item Personality Measure). In both conditions participants provided saliva samples (for hormone assays). In the challenge condition there was a highly significant increase in HGS, and modest changes in T, physical aggression and emotional stability. HGS correlated negatively with left hand 2D:4D. In a multiple regression, left hand 2D:4D was negatively related to HGS and emotional stability was positively related to HGS. In the control condition HGS was not correlated with 2D:4D. In a multiple regression, BMI, physical aggression, and emotional stability were significantly related to HGS. 2D:4D is a negative correlate of strength in challenge situations. This finding may in part explain associations between 2D:4D and sports performance. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  16. Anti-inflammatory and anti-oxidant effects of Cardamom (Elettaria repens (Sonn.) Baill) and its phytochemical analysis by 4D GCXGC TOF-MS.

    PubMed

    Kandikattu, Hemanth Kumar; Rachitha, P; Jayashree, G V; Krupashree, K; Sukhith, M; Majid, Abdul; Amruta, Narayanappa; Khanum, Farhath

    2017-07-01

    Elleteria repens is a large cardamom used in the culinary preparations. In the present study, we have evaluated in vitro antioxidant and free radical scavenging activities E. repens hexane extract (ERH) exhibited DPPH and metal chelating activity with IC50 values of 464±28.3μg/ml, 199±7.2μg/ml whereas the reducing power and antioxidant activities are found to be 289±14.6 AAE/mg, 468±22.7 GAE/mg. The observed antioxidant activities could be correlated with metabolites such as polyphenol, flavonoid, and terpenoid group of compounds identified in hexane fraction of E. repens by 4D GCXGC TOF-MS. Further ERH was evaluated for its protective properties against macromolecules such as DNA, protein and lipid damage. The extract showed protection against H2O2 induced DNA damage and inhibited AAPH induced protein oxidation and lipid peroxidation. Moreover, ERH administration to rats at 50 and 100mg/kg inhibited carrageenan-induced paw edema, and down-regulated cytokines such as COX-2, IL-6, and TNF-α and inhibited i-NOS mediated NO generation. E. repens also exhibited antioxidant effects by restoring SOD, catalase, GSH levels and inhibited lipid peroxidation in carrageenan challenged rats. Overall, the results suggest that E. repens may be useful in combating inflammation and oxidative stress. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  17. Finger length ratios (2D:4D) in anthropoids implicate reduced prenatal androgens in social bonding.

    PubMed

    Nelson, Emma; Shultz, Susanne

    2010-03-01

    The second-to-fourth digit ratio (2D:4D) has been proposed as a biomarker reflecting prenatal androgen effects (PAE), such that individuals with lower ratios have experienced higher PAE than those with higher ratios. 2D:4D has been correlated with a number of sex-linked traits in humans such as aggression, promiscuity, and competitiveness. In addition, polygynous societies reportedly have lower 2D:4D (higher PAE) than more monogamous populations. This evidence suggests that PAE may be implicated in the development of sexually selected behaviors in humans. To place 2D:4D research into a broader context, we test the relationship between digit ratios and behavior across nonhuman anthropoids; polygynous species, with higher levels of intrasexual competition, should have more pronounced markers of PAE (lower 2D:4D) than pair-bonded species. Our results accord with those found in humans: 2D:4D is lower in polygynous species and higher (lower PAE) in pair-bonded species. Old World monkeys have low, and relatively invariant 2D:4D (high PAE), which is coupled with high levels of intrasexual competition. This contrasts with higher and more variable ratios in both great apes and New World monkeys. In addition, both male and female ratios decrease with increasing levels of intrasexual competition. Human ratios are intermediate between pair-bonded and more promiscuous hominoids. We propose that PAE may be involved in promoting species characteristic social behavior in anthropoids.

  18. cAMP/PKA/CREB/GLT1 signaling involved in the antidepressant-like effects of phosphodiesterase 4D inhibitor (GEBR-7b) in rats

    PubMed Central

    Liu, Xu; Guo, Haibiao; Sayed, Mohammad Daud SOM; Lu, Yang; Yang, Ting; Zhou, Dongsheng; Chen, Zhongming; Wang, Haitao; Wang, Chuang; Xu, Jiangping

    2016-01-01

    Objectives GEBR-7b, a potential phosphodiesterase 4D inhibitor, has been shown to have memory-enhancing effects in rodents. However, it is still unknown whether GEBR-7b also has the antidepressant-like effects in rats. Herein, we examined the potential of GEBR-7b to attenuate depression-like behaviors in the rat model of depression induced by chronic unpredictable stress (CUS). Next, we also investigated the alterations of cyclic adenosine monophosphate (cAMP), protein kinase A (PKA) catalytic subunit (PKAca), cAMP response element-binding (CREB), and glutamate transporter 1 (GLT1) levels produced by GEBR-7b in the rats model of depression. Methods Effects of GEBR-7b on CUS (35 days)-induced depression-like behaviors were examined by measuring immobility time in the forced swimming test (FST). Hippocampal cAMP levels were examined by enzyme-linked immunosorbent assay, whereas PKAca, phosphorylation of CREB (pCREB), CREB, and GLT1 in the hippocampus of rats were subjected to Western blot analysis. Results CUS exposure caused a depression-like behavior evidenced by the increased immobility time in FST. Depression-like behavior induced by CUS was accompanied by a significant increased GLT, decreased cAMP, PKAca, pCREB activities in hippocampus. However, repeated GEBR-7b administration significantly reversed CUS-induced depression-like behavior and changes of cAMP/PKA/CREB/GLT1 signaling. No alteration was observed in locomotor activity in open field test. Conclusion These findings indicate that GEBR-7b reversed the depression-like behaviors induced by CUS in rats, which is at least in part mediated by modulating cAMP, PKAca, pCREB, and GLT1 levels in the hippocampus of rats, supporting its neuroprotective potential against behavioral and biochemical dysfunctions induced by CUS. PMID:26855578

  19. Symmetries and vanishing couplings in string-derived low energy effective field theory

    SciTech Connect

    Kobayashi, Tatsuo

    2012-07-27

    We study 4D low-energy effective field theory, derived from heterotic string theory on the orbifolds. In particular, we study Abelian and non-Abelian discrete symmetries and their anomalies. Furthermore, stringy computations also provide with stringy coupling selection rules.

  20. The 4D nucleome project.

    PubMed

    Dekker, Job; Belmont, Andrew S; Guttman, Mitchell; Leshyk, Victor O; Lis, John T; Lomvardas, Stavros; Mirny, Leonid A; O'Shea, Clodagh C; Park, Peter J; Ren, Bing; Politz, Joan C Ritland; Shendure, Jay; Zhong, Sheng

    2017-09-13

    The 4D Nucleome Network aims to develop and apply approaches to map the structure and dynamics of the human and mouse genomes in space and time with the goal of gaining deeper mechanistic insights into how the nucleus is organized and functions. The project will develop and benchmark experimental and computational approaches for measuring genome conformation and nuclear organization, and investigate how these contribute to gene regulation and other genome functions. Validated experimental technologies will be combined with biophysical approaches to generate quantitative models of spatial genome organization in different biological states, both in cell populations and in single cells.

  1. Effect of 2,4-Dichlorophenoxyacetic Acid (2,4-D) on PCDD/F Emissions from Open Burning of Biomass

    EPA Science Inventory

    Use of pesticides prior to agricultural burning and overspray onto forests and grasslands prior to fires has been cited as a cause of halogenated organic compound emissions from biomass combustion. Some pesticides such as 2,4-dichlorophenoxyacetic acid (2,4-D) are used in conside...

  2. Effect of 2,4-Dichlorophenoxyacetic Acid (2,4-D) on PCDD/F Emissions from Open Burning of Biomass

    EPA Science Inventory

    Use of pesticides prior to agricultural burning and overspray onto forests and grasslands prior to fires has been cited as a cause of halogenated organic compound emissions from biomass combustion. Some pesticides such as 2,4-dichlorophenoxyacetic acid (2,4-D) are used in conside...

  3. E4D_RT

    SciTech Connect

    2016-03-22

    Time-lapse ERT imaging for monitoring both natural and engineered subsurface processes has advanced rapidly over the past 15-20 years. However, imaging results generally required a significant amount of manual and computational effort, and therefore were not available while the process was occurring. Although the value of real-time imaging was recognized, several obstacles prevented it's implementation. E4D_RT addresses these obstacles by 1) providing specialized algorithms that negate the need for user intervention, thereby automating the time-lapse data processing steps, 2) linking field data collection systems with parallel supercomputing systems via wireless data transfer link, and 3) addressing the computational burdens by utilizing distributed memory supercomputing resources, thereby enabling rapid data processing and imaging results.

  4. Two-phase (low-dose) computed tomography is as effective as 4D-CT for identifying enlarged parathyroid glands.

    PubMed

    Campbell, Michael J; Sicuro, Paul; Alseidi, Adnan; Blackmore, C Craig; Ryan, John A

    2015-02-01

    Four-dimensional computed tomography (4D-CT) is often used for patients with primary hyperparathyroidism and non-definitive localization after Sestamibi scan (MIBI) and ultrasound (US), but may expose patients to unnecessary radiation, typically between 10 and 26 millisieverts (mSv). We hypothesize that a simpler two-phase CT protocol would have a similar sensitivity, specificity and accuracy to those published for 4D-CT, while exposing the patient to less radiation. We reviewed 54 patients with primary hyperparathyroidism and non-definitive localization studies who had a two-phase CT between 2009 and 2012 at our tertiary referral center. The mean radiation dose of two-phase CT over the course of the study was 5.2 mSv (range 3.5 mSv-9.1 mSv). Two-phase CT had a 77% (CI = 65%-86%) sensitivity and an 87% (CI = 73%-95%) specificity to lateralize enlarged parathyroid glands to the correct side of the neck and a 58% (CI = 45%-68%) sensitivity and 91% (CI = 83%-94%) specificity to localize parathyroid tumors to the correct quadrant of the neck. The overall accuracy of two-phase CT to lateralize enlarged parathyroids was 81% (CI = 73%, 88%) and the accuracy to localize enlarged parathyroids was 79% (CI = 73%, 84%). As a second line investigation two-phase CT has a similar sensitivity, specificity and accuracy to those published for 4D-CT in patients with non-localized, enlarged parathyroids with less radiation exposure. Two-phase CT can help localize enlarged parathyroid glands not definitively identified using MIBI and US. Two-phase CT allows clinicians to accurately identify enlarged parathyroid glands while exposing the patient to less radiation than 4D-CT. Copyright © 2015 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.

  5. The effect of resolution on viscous dissipation measured with 4D flow MRI in patients with Fontan circulation: Evaluation using computational fluid dynamics

    PubMed Central

    Cibis, Merih; Jarvis, Kelly; Markl, Michael; Rose, Michael; Rigsby, Cynthia; Barker, Alex J.; Wentzel, Jolanda J.

    2016-01-01

    Viscous dissipation inside Fontan circulation, a parameter associated with the exercise intolerance of Fontan patients, can be derived from computational fluid dynamics (CFD) or 4D flow MRI velocities. However, the impact of spatial resolution and measurement noise on the estimation of viscous dissipation is unclear. Our aim was to evaluate the influence of these parameters on viscous dissipation calculation. Six Fontan patients underwent whole heart 4D flow MRI. Subject-specific CFD simulations were performed. The CFD velocities were down-sampled to isotropic spatial resolutions of 0.5 mm, 1 mm, 2 mm and to MRI resolution. Viscous dissipation was compared between (1) high resolution CFD velocities, (2) CFD velocities down-sampled to MRI resolution, (3) down-sampled CFD velocities with MRI mimicked noise levels, and (4) in-vivo 4D flow MRI velocities. Relative viscous dissipation between subjects was also calculated. 4D flow MRI velocities (15.6±3.8 cm/s) were higher, although not significantly different than CFD velocities (13.8±4.7 cm/s, p=0.16), down-sampled CFD velocities (12.3±4.4 cm/s, p=0.06) and the down-sampled CFD velocities with noise (13.2±4.2 cm/s, p=0.06). CFD-based viscous dissipation (0.81±0.55 mW) was significantly higher than those based on down-sampled CFD (0.25±0.19 mW, p=0.03), down-sampled CFD with noise (0.49±0.26 mW, p=0.03) and 4D flow MRI (0.56±0.28 mW, p=0.06). Nevertheless, relative viscous dissipation between different subjects was maintained irrespective of resolution and noise, suggesting that comparison of viscous dissipation between patients is still possible. PMID:26298492

  6. Respiratory gating and 4-D tomotherapy

    SciTech Connect

    Zhang Tiezhi

    2004-12-01

    Helical tomotherapy is a new intensity-modulated radiotherapy (IMRT) delivery process developed at the University of Wisconsin and TomoTherapy Inc. Tomotherapy may be of advantage in lung cancer treatment due to its rotational delivery mode. As with conventional IMRT delivery, however, intrafraction respiratory motion during a tomotherapy treatment causes unnecessary radiation to the healthy tissue. Possible solutions to these problems associated with intrafraction motion have been studied in this thesis. A spirometer is useful for monitoring breathing because of its direct correlation with lung volume changes. However, its inherent drift prevents its application in long-term breathing monitoring. With calibration and stabilization algorithms, a spirometer is able to provide accurate, long-term lung volume change measurements. Such a spirometer system is most suited for deep inspiration breath-hold (DIBH) treatments. An improved laser-spirometer combined system has also been developed for target tracking in 4-D treatment. Spirometer signals are used to calibrate the displacement measurements into lung volume changes, thereby eliminating scaling errors from daily setup variations. The laser displacement signals may also be used to correct spirometer drifts during operation. A new 4-D treatment technique has been developed to account for intrafraction motion in treatment planning. The patient's breathing and the beam delivery are synchronized, and the target motion/deformation is incorporated into treatment plan optimization. Results show that this new 4D treatment technique significantly reduces motion effects and provides improved patient tolerance.

  7. Evidence for assortative mating on digit ratio (2D:4D), a biomarker for prenatal androgen exposure.

    PubMed

    Voracek, Martin; Dressler, Stefan G; Manning, John T

    2007-07-01

    The second-to-fourth digit ratio (2D:4D) presents an anatomical sex difference in humans. On average, men tend to have lower 2D:4D compared with women. There is fairly strong evidence for a role of the 2D:4D ratio as a biomarker for the organizational (permanent) effects of prenatal testosterone on the brain and behaviour. Recently, an accumulating research programme has shown 2D:4D to be related to a multitude of sex-dependent, hormonally influenced biosocial traits and phenotypes which reach into the domains of ability, behaviour, fertility, health, personality and sexuality. This study investigated the degree of assortative mating (spousal similarity) in a sample of 239 native Austrian couples of parental or grandparental age, all of them having reproduced. Results included: (i) significant spousal correlations of +0.19 and +0.18 for right-hand and left-hand 2D:4D, respectively, and +0.24 for average 2D:4D; (ii) no assortative mating effect on the right-minus-left difference in 2D:4D; (iii) indications consistent with a possible generational decrease of spousal similarity in 2D:4D; (iv) a prevalence of couples with a lower right-hand 2D:4D observed in the husband compared with his wife; and (v) relations of spousal 2D:4D patterns to spousal age differences, such that matings of men with more male-typical trait expressions (namely, a generally low right-hand 2D:4D or showing a lower right-minus-left 2D:4D difference than their wives) implicated larger male-minus-female age differences, i.e. younger wives. It is argued that assortative mating on 2D:4D operates indirectly and may be mediated through the assortment on other, more perceptible, physical traits and psychological phenotypes that entertain associations with 2D:4D and are relevant for courtship and mate choice.

  8. The effect of the glyphosate, 2,4-D, atrazine e nicosulfuron herbicides upon the Edaphic collembola (Arthropoda: Ellipura) in a no tillage system.

    PubMed

    Lins, Vilma S; Santos, Honório R; Gonçalves, Manoel C

    2007-01-01

    The use of herbicides is a common and intensive practice in no tillage systems. The herbicides can influence, directly or indirectly, the population of edaphic arthropods. Collembola is a group that functions as a bio-indicator of soil conditions. The degree of abundance and diversity of Collembola provides the level of soil disturbance provoked by agricultural practices. This experiment was designed to compare the influence of herbicides on the population fluctuation of Collembola in a no-till soil preparation system. The work was conducted in a non irrigated no-till area at the Núcleo Experimental de Ciências Agrárias of the Universidade Federal de Mato Grosso do Sul (UFMS), Campus de Dourados, in soil planted with corn as a surface covering, during the period of December, 2002 to December, 2003. The data were analyzed according to a completely randomized model, in a split plot design. The plots received four types of herbicides: glyphosate, atrazine, 2,4-D and nicosulfuron. A fifth plot did not receive any herbicide (control), for a total of five treatment types. The sub plots were represented by their collection times (10, 20, 30 and 40 days after the herbicide applications). Both the type of herbicide and the time of data sampling influenced the Collembola population fluctuaction. The treatments with atrazine and 2,4-D caused the most reduction of the population of Collembola, depending on the time of application.

  9. Effects of 4D-Var data assimilation using remote sensing precipitation products in a WRF over the complex Heihe River Basin

    NASA Astrophysics Data System (ADS)

    Pan, Xiaoduo; Li, Xin; Cheng, Guodong

    2017-04-01

    Traditionally, ground-based, in situ observations, remote sensing, and regional climate modeling, individually, cannot provide the high-quality precipitation data required for hydrological prediction, especially over complex terrain. Data assimilation techniques are often used to assimilate ground observations and remote sensing products into models for dynamic downscaling. In this study, the Weather Research and Forecasting (WRF) model was used to assimilate two satellite precipitation products (TRMM 3B42 and FY-2D) using the 4D-Var data assimilation method. The results show that the assimilation of remote sensing precipitation products can improve the initial WRF fields of humidity and temperature, thereby improving precipitation forecasting and decreasing the spin-up time. Hence, assimilating TRMM and FY-2D remote sensing precipitation products using WRF 4D-Var can be viewed as a positive step toward improving the accuracy and lead time of numerical weather prediction models, particularly for short-term weather forecasting. Future work is proposed to assimilate a suite of remote sensing data, e.g., the combination of precipitation and soil moisture data, into a WRF model to improve 7-8 day forecasts of precipitation and other atmospheric variables.

  10. Inverse Vernier effect in coupled lasers

    NASA Astrophysics Data System (ADS)

    Ge, Li; Türeci, Hakan E.

    2015-07-01

    In this report we study the Vernier effect in coupled laser systems consisting of two cavities. We show that depending on the nature of their coupling, not only can the "supermodes" formed at overlapping resonances of these two cavities have the lowest thresholds as previously found, leading to lasing at these overlapping resonances and a manifestation of the typical Vernier effect, but also they can have increased thresholds and are hence suppressed, which can be viewed as an inverse Vernier effect. The inverse Vernier effect can also lead to an increased free spectrum range and possibly single-mode lasing, which may explain the experimental findings in several previous studies. We illustrate this effect using two coupled micro-ring cavities and a micro-ring cavity coupled to a slab cavity, and we discuss its relation to the existence of exceptional points in coupled lasers.

  11. 4D scattering amplitudes and asymptotic symmetries from 2D CFT

    NASA Astrophysics Data System (ADS)

    Cheung, Clifford; de la Fuente, Anton; Sundrum, Raman

    2017-01-01

    We reformulate the scattering amplitudes of 4D flat space gauge theory and gravity in the language of a 2D CFT on the celestial sphere. The resulting CFT structure exhibits an OPE constructed from 4D collinear singularities, as well as infinite-dimensional Kac-Moody and Virasoro algebras encoding the asymptotic symmetries of 4D flat space. We derive these results by recasting 4D dynamics in terms of a convenient foliation of flat space into 3D Euclidean AdS and Lorentzian dS geometries. Tree-level scattering amplitudes take the form of Witten diagrams for a continuum of (A)dS modes, which are in turn equivalent to CFT correlators via the (A)dS/CFT dictionary. The Ward identities for the 2D conserved currents are dual to 4D soft theorems, while the bulk-boundary propagators of massless (A)dS modes are superpositions of the leading and subleading Weinberg soft factors of gauge theory and gravity. In general, the massless (A)dS modes are 3D Chern-Simons gauge fields describing the soft, single helicity sectors of 4D gauge theory and gravity. Consistent with the topological nature of Chern-Simons theory, Aharonov-Bohm effects record the "tracks" of hard particles in the soft radiation, leading to a simple characterization of gauge and gravitational memories. Soft particle exchanges between hard processes define the Kac-Moody level and Virasoro central charge, which are thereby related to the 4D gauge coupling and gravitational strength in units of an infrared cutoff. Finally, we discuss a toy model for black hole horizons via a restriction to the Rindler region.

  12. 4D scattering amplitudes and asymptotic symmetries from 2D CFT

    DOE PAGES

    Cheung, Clifford; de la Fuente, Anton; Sundrum, Raman

    2017-01-25

    We reformulate the scattering amplitudes of 4D at space gauge theory and gravity in the language of a 2D CFT on the celestial sphere. The resulting CFT structure exhibits an OPE constructed from 4D collinear singularities, as well as infinite-dimensional Kac-Moody and Virasoro algebras encoding the asymptotic symmetries of 4D at space. We derive these results by recasting 4D dynamics in terms of a convenient foliation of flat space into 3D Euclidean AdS and Lorentzian dS geometries. Tree-level scattering amplitudes take the form of Witten diagrams for a continuum of (A)dS modes, which are in turn equivalent to CFT correlatorsmore » via the (A)dS/CFT dictionary. The Ward identities for the 2D conserved currents are dual to 4D soft theorems, while the bulk-boundary propagators of massless (A)dS modes are superpositions of the leading and subleading Weinberg soft factors of gauge theory and gravity. In general, the massless (A)dS modes are 3D Chern-Simons gauge fields describing the soft, single helicity sectors of 4D gauge theory and gravity. Consistent with the topological nature of Chern-Simons theory, Aharonov-Bohm effects record the \\tracks" of hard particles in the soft radiation, leading to a simple characterization of gauge and gravitational memories. Soft particle exchanges between hard processes define the Kac-Moody level and Virasoro central charge, which are thereby related to the 4D gauge coupling and gravitational strength in units of an infrared cutoff. Lastly, we discuss a toy model for black hole horizons via a restriction to the Rindler region.« less

  13. Dynamic effects of magnetic multilayer interlayer coupling

    SciTech Connect

    Pechan, M.J.; Xu, J. . Dept. of Physics); Kelly, D.M.; Schuller, I.K. . Dept. of Physics)

    1993-11-01

    Coupling between magnetic layers in multilayer samples gives rise to dynamic effects which are manifest as anomalous modes in ferromagnetic resonance (FMR) spectra. According to the model presented, antiferromagnetic (ferromagnetic) coupling would produce such modes on the high (low) field side of the uniform FMR mode. Anomalous modes, observed in Fe/Cu and Fe/Cr multilayer samples, are analyzed to obtain coupling constants as a function of nonmagnetic layer thickness. The modes are shown to arise from 180 out-of-phase interlayer magnetization precession. The coupling is observed to be antiferromagnetic in all samples and to be an order of magnitude greater in the Cr system than in the Cu.

  14. Chimera states: Effects of different coupling topologies

    NASA Astrophysics Data System (ADS)

    Bera, Bidesh K.; Majhi, Soumen; Ghosh, Dibakar; Perc, Matjaž

    2017-04-01

    Collective behavior among coupled dynamical units can emerge in various forms as a result of different coupling topologies as well as different types of coupling functions. Chimera states have recently received ample attention as a fascinating manifestation of collective behavior, in particular describing a symmetry breaking spatiotemporal pattern where synchronized and desynchronized states coexist in a network of coupled oscillators. In this perspective, we review the emergence of different chimera states, focusing on the effects of different coupling topologies that describe the interaction network connecting the oscillators. We cover chimera states that emerge in local, nonlocal and global coupling topologies, as well as in modular, temporal and multilayer networks. We also provide an outline of challenges and directions for future research.

  15. Interface effect in coupled quantum wells

    SciTech Connect

    Hao, Ya-Fei

    2014-06-28

    This paper intends to theoretically investigate the effect of the interfaces on the Rashba spin splitting of two coupled quantum wells. The results show that the interface related Rashba spin splitting of the two coupled quantum wells is both smaller than that of a step quantum well which has the same structure with the step quantum well in the coupled quantum wells. And the influence of the cubic Dresselhaus spin-orbit interaction of the coupled quantum wells is larger than that of a step quantum well. It demonstrates that the spin relaxation time of the two coupled quantum wells will be shorter than that of a step quantum well. As for the application in the spintronic devices, a step quantum well may be better than the coupled quantum wells, which is mentioned in this paper.

  16. Adaptive 4D volume perfusion CT of lung cancer: effects of computerized motion correction and the range of volume coverage on measurement reproducibility.

    PubMed

    Lee, Sang Min; Lee, Hyun-Ju; Kim, Jung Im; Kang, Mi-Jin; Goo, Jin Mo; Park, Chang Min; Im, Jung-Gi

    2013-06-01

    The purpose of this study was to determine whether measurement reproducibility can be improved using computerized motion correction and whole-tumor coverage in adaptive 4D perfusion CT of lung cancer. Perfusion CT covering the entire z-axis of a mass was performed of 40 patients with lung cancer. Each perfusion CT study was performed in 93.5 seconds and included 17 repeated dynamic CT scans obtained using the Adaptive 4D Spiral mode. Tumor blood flow (BF), blood volume (BV), and permeability were measured in four different manners: in the entire tumor (whole-tumor coverage) without the use of motion correction; in the entire tumor with motion correction; in a small volume of interest (VOI) of tumor without motion correction; and in a small VOI with motion correction. Intra- and interobserver reproducibility were assessed through Bland-Altman analyses. The 95% limits of intraobserver reproducibility for BF, BV, and permeability were as follows: -52.1% to 48.0%, -22.4% to 27.8%, and -33.2% to 38.5%, respectively, in the whole tumor without motion correction; -53.3% to 45.6%, -17.7% to 20.6%, and -31.5% to 37.0% in the whole tumor with motion correction; -107.8% to 97.4%, -98.3% to 93.7%, and -132.3% to 100.7% in a small VOI of tumor without motion correction; and -74.9% to 98.6%, -74.5% to 88.1%, and -109.8% to 114.1% in a small VOI with motion correction. The 95% limits of interobserver reproducibility for BF, BV, and permeability were as follows: -57.0% to 62.5%, -36.8% to 52.6%, and -47.7% to 66.0%, respectively, in the whole tumor without motion correction; -55.7% to 55.8%, -25.8% to 42.0%, and -35.3% to 46.7% in the whole tumor with motion correction; -146.6% to 165.1%, -117.1% to 137.7%, and -143.2% to 149.8% in a small VOI of tumor without motion correction; and -106.2% to 133.6%, -99.5% to 122.4%, and -108.6% to 170.0% in a small VOI of tumor with motion correction. Overall, the best reproducibility was obtained when measurements were obtained in the entire

  17. 4-D OCT in Developmental Cardiology

    NASA Astrophysics Data System (ADS)

    Jenkins, Michael W.; Rollins, Andrew M.

    Although strong evidence exists to suggest that altered cardiac function can lead to CHDs, few studies have investigated the influential role of cardiac function and biophysical forces on the development of the cardiovascular system due to a lack of proper in vivo imaging tools. 4-D imaging is needed to decipher the complex spatial and temporal patterns of biomechanical forces acting upon the heart. Numerous solutions over the past several years have demonstrated 4-D OCT imaging of the developing cardiovascular system. This chapter will focus on these solutions and explain their context in the evolution of 4-D OCT imaging. The first sections describe the relevant techniques (prospective gating, direct 4-D imaging, retrospective gating), while later sections focus on 4-D Doppler imaging and measurements of force implementing 4-D OCT Doppler. Finally, the techniques are summarized, and some possible future directions are discussed.

  18. Evidence of apoptotic effects of 2,4-D and butachlor on walking catfish, Clarias batrachus, by transmission electron microscopy and DNA degradation studies.

    PubMed

    Ateeq, Bushra; Farah, M Abul; Ahmad, Waseem

    2006-01-25

    Apoptosis or programmed cell death is characterized morphologically by chromatin condensation, cell shrinkage, fragmentation of the nucleus and cytoplasm, and consequently formation of apoptotic bodies. It has also been best characterized by the cleavage of DNA into nucleosomal size fragments of 180-200 bp or multiples of the same. Contrary to this, under extreme conditions, the cells were found to show adaptive response to apoptosis and unable to regulate their own death; necrosis is therefore predominantly observed. In the present study, we showed induction of apoptosis in Clarias batrachus due to sublethal concentration of 2,4-D and butachlor at multiple exposure time. The first phase of the study involved light microscopy (LM) and transmission electron microscopy (TEM) for ultrastructural abnormalities of the germinal tissues. While, in the second phase of the study, DNA degradation of blood and hepatic tissue was resolved on agarose gel electrophoresis. In histopathological studies, large numbers of stage II oocytes were noted for nuclear blebbing irrespective of the test chemical. Some of the butachlor-exposed oocytes showed vacuolation and electron dense cytoplasm along with thickened nuclear envelope, having close association with the lysosomes on the cytoplasmic side. Some oocytes undergo nuclear blebbing having inner dense core and translucent cytoplasm. Leydig cells were slightly hypertrophied and few appeared pycnotic, a process involving necrotic changes in which the cell nuclei were characterized by rounding up and condensation resulting in hyperchromatic staining or pycnosis. In testicular tissue, spermatogonial nuclei had irregular large clumps of heterochromatin adjoining the nuclear membrane indicating initial stage of apoptotic cell death. Electrophoretic separation resulted in a ladder pattern of blood DNA and smear like pattern of hepatic DNA. These results indicate that the above herbicides are able to induce apoptosis both at molecular as

  19. Experimental validation of a 4D elastic registration algorithm.

    PubMed

    Leung, Corina; Hashtrudi-Zaad, Keyvan; Foroughi, Pezhman; Abolmaesumi, Purang

    2008-01-01

    This paper presents an extensive validation study of an elastic registration algorithm for dynamic 3D ultrasound images (also known as a 4D image). The registration algorithm uses attribute vectors from both a fixed and previous moving images to perform feature-based alignment of a series of images. The 4D method reduces computational requirements and increases the effective search space for the location of corresponding features, resulting in enhanced registration speed when compared to a static 3D registration technique. Experimental analysis revealed up to 32% improvement in speed when using the 4D method, which makes the algorithm attractive for real-time applications.

  20. Advances in 4D radiation therapy for managing respiration: part I - 4D imaging.

    PubMed

    Hugo, Geoffrey D; Rosu, Mihaela

    2012-12-01

    Techniques for managing respiration during imaging and planning of radiation therapy are reviewed, concentrating on free-breathing (4D) approaches. First, we focus on detailing the historical development and basic operational principles of currently-available "first generation" 4D imaging modalities: 4D computed tomography, 4D cone beam computed tomography, 4D magnetic resonance imaging, and 4D positron emission tomography. Features and limitations of these first generation systems are described, including necessity of breathing surrogates for 4D image reconstruction, assumptions made in acquisition and reconstruction about the breathing pattern, and commonly-observed artifacts. Both established and developmental methods to deal with these limitations are detailed. Finally, strategies to construct 4D targets and images and, alternatively, to compress 4D information into static targets and images for radiation therapy planning are described.

  1. Controlled Source 4D Seismic Imaging

    NASA Astrophysics Data System (ADS)

    Luo, Y.; Morency, C.; Tromp, J.

    2009-12-01

    Earth's material properties may change after significant tectonic events, e.g., volcanic eruptions, earthquake ruptures, landslides, and hydrocarbon migration. While many studies focus on how to interpret observations in terms of changes in wavespeeds and attenuation, the oil industry is more interested in how we can identify and locate such temporal changes using seismic waves generated by controlled sources. 4D seismic analysis is indeed an important tool to monitor fluid movement in hydrocarbon reservoirs during production, improving fields management. Classic 4D seismic imaging involves comparing images obtained from two subsequent seismic surveys. Differences between the two images tell us where temporal changes occurred. However, when the temporal changes are small, it may be quite hard to reliably identify and characterize the differences between the two images. We propose to back-project residual seismograms between two subsequent surveys using adjoint methods, which results in images highlighting temporal changes. We use the SEG/EAGE salt dome model to illustrate our approach. In two subsequent surveys, the wavespeeds and density within a target region are changed, mimicking possible fluid migration. Due to changes in material properties induced by fluid migration, seismograms recorded in the two surveys differ. By back propagating these residuals, the adjoint images identify the location of the affected region. An important issue involves the nature of model. For instance, are we characterizing only changes in wavespeed, or do we also consider density and attenuation? How many model parameters characterize the model, e.g., is our model isotropic or anisotropic? Is acoustic wave propagation accurate enough or do we need to consider elastic or poroelastic effects? We will investigate how imaging strategies based upon acoustic, elastic and poroelastic simulations affect our imaging capabilities.

  2. Dual coupling effective band model for polarons

    NASA Astrophysics Data System (ADS)

    Marchand, Dominic J. J.; Stamp, Philip C. E.; Berciu, Mona

    2017-01-01

    Nondiagonal couplings to a bosonic bath completely change polaronic dynamics, from the usual diagonally coupled paradigm of smoothly varying properties. We study, using analytic and numerical methods, a model having both diagonal Holstein and nondiagonal Su-Schrieffer-Heeger (SSH) couplings. The critical coupling found previously in the pure SSH model, at which the k =0 effective mass diverges, now becomes a transition line in the coupling constant plane—the form of the line depends on the adiabaticity parameter. Detailed results are given for the quasiparticle and ground-state properties, over a wide range of couplings and adiabaticity ratios. The new paradigm involves a destabilization, at the transition line, of the simple Holstein polaron to one with a finite ground-state momentum, but with everywhere a continuously evolving band shape. No "self-trapping transition" exists in any of these models. The physics may be understood entirely in terms of competition between different hopping terms in a simple renormalized effective band theory. The possibility of further transitions is suggested by the results.

  3. Coupling effect on the Berry phase

    NASA Astrophysics Data System (ADS)

    Tian, Lijing; Yang, Zhi; Shi, Q. W.; Li, Qunxiang; Wang, X. P.

    2016-11-01

    The Berry phase has universal applications in various fields. Here, we explore the coupling effect on the Berry phase of a two-level system adiabatically driven by a rotating classical field and interacting with a single quantized mode. Our simulations clearly reveal that the Berry phase change is quadratic proportional to the coupling constant if it is less than the level spacing between neighboring instantaneous eigenstates. Remarkably, if the nearest neighbouring level spacing is comparable with the coupling constant, this simple quadratic dependence is lost. Around this resonance, the Berry phase can be significantly tuned by slightly adjusting the parameters, such as the coupling constant, the frequency of the quantized mode, and the transition frequency. These numerical results, agreeing well with the perturbation theory calculations, provide an alternative approach to tune the Berry phase near the resonance, which is useful in quantum information science, i.e. designing quantum logic gates.

  4. Acceleration effect of coupled oscillator systems

    NASA Astrophysics Data System (ADS)

    Aonishi, Toru; Kurata, Koji; Okada, Masato

    2002-04-01

    We have developed a curved isochron clock (CIC) by modifying the radial isochron clock to provide a clean example of the acceleration (deceleration) effect. By analyzing a two-body system of coupled CICs, we determined that an unbalanced mutual interaction caused by curved isochron sets is the minimum mechanism needed for generating the acceleration (deceleration) effect in coupled oscillator systems. From this we can see that the Sakaguchi and Kuramoto (SK) model, which is a class of nonfrustrated mean field model, has an acceleration (deceleration) effect mechanism. To study frustrated coupled oscillator systems, we extended the SK model to two oscillator associative memory models, one with symmetric and the other with asymmetric dilution of coupling, which also have the minimum mechanism of the acceleration (deceleration) effect. We theoretically found that the Onsager reaction term (ORT), which is unique to frustrated systems, plays an important role in the acceleration (deceleration) effect. These two models are ideal for evaluating the effect of the ORT because, with the exception of the ORT, they have the same order parameter equations. We found that the two models have identical macroscopic properties, except for the acceleration effect caused by the ORT. By comparing the results of the two models, we can extract the effect of the ORT from only the rotation speeds of the oscillators.

  5. Optimized PET imaging for 4D treatment planning in radiotherapy: the virtual 4D PET strategy.

    PubMed

    Gianoli, Chiara; Riboldi, Marco; Fontana, Giulia; Giri, Maria G; Grigolato, Daniela; Ferdeghini, Marco; Cavedon, Carlo; Baroni, Guido

    2015-02-01

    The purpose of the study is to evaluate the performance of a novel strategy, referred to as "virtual 4D PET", aiming at the optimization of hybrid 4D CT-PET scan for radiotherapy treatment planning. The virtual 4D PET strategy applies 4D CT motion modeling to avoid time-resolved PET image acquisition. This leads to a reduction of radioactive tracer administered to the patient and to a total acquisition time comparable to free-breathing PET studies. The proposed method exploits a motion model derived from 4D CT, which is applied to the free-breathing PET to recover respiratory motion and motion blur. The free-breathing PET is warped according to the motion model, in order to generate the virtual 4D PET. The virtual 4D PET strategy was tested on images obtained from a 4D computational anthropomorphic phantom. The performance was compared to conventional motion compensated 4D PET. Tests were also carried out on clinical 4D CT-PET scans coming from seven lung and liver cancer patients. The virtual 4D PET strategy was able to recover lesion motion, with comparable performance with respect to the motion compensated 4D PET. The compensation of the activity blurring due to motion was successfully achieved in terms of spill out removal. Specific limitations were highlighted in terms of partial volume compensation. Results on clinical 4D CT-PET scans confirmed the efficacy in 4D PET count statistics optimization, as equal to the free-breathing PET, and recovery of lesion motion. Compared to conventional motion compensation strategies that explicitly require 4D PET imaging, the virtual 4D PET strategy reduces clinical workload and computational costs, resulting in significant advantages for radiotherapy treatment planning.

  6. Los Alamos National Laboratory 4D Database

    SciTech Connect

    Atencio, Julian J.

    2014-05-02

    4D is an integrated development platform - a single product comprised of the components you need to create and distribute professional applications. You get a graphical design environment, SQL database, a programming language, integrated PHP execution, HTTP server, application server, executable generator, and much more. 4D offers multi-platform development and deployment, meaning whatever you create on a Mac can be used on Windows, and vice-versa. Beyond productive development, 4D is renowned for its great flexibility in maintenance and modification of existing applications, and its extreme ease of implementation in its numerous deployment options. Your professional application can be put into production more quickly, at a lower cost, and will always be instantly scalable. 4D makes it easy, whether you're looking to create a classic desktop application, a client-server system, a distributed solution for Web or mobile clients - or all of the above!

  7. 4D superfield reduction of 5D orbifold SUGRA and heterotic M-theory

    NASA Astrophysics Data System (ADS)

    Paccetti Correia, Filipe; Schmidt, Michael G.; Tavartkiladze, Zurab

    2006-09-01

    We present a detailed study of the reduction to 4D of 5D supergravity compactified on the S/Z orbifold. For this purpose we develop and employ a recently proposed N=1 conformal superfield description of the 5D supergravity couplings to Abelian vector and hypermultiplets. In particular, we obtain a unique relation of the "radion" to chiral superfields as in global 5D SUSY and we can embed the universal hypermultiplet into this formalism. In our approach, it is transparent how the superconformal structure of the effective 4D actions is inherited from the one of the original 5D supergravity. We consider both ungauged and gauged 5D supergravities. This includes compactifications in unwarped geometries, generalizations of the supersymmetric Randall-Sundrum (RS) model as well as 5D heterotic M-theory. In the unwarped case, after obtaining the effective Kähler potentials and superpotentials, we demonstrate that the tree-level 4D potentials have flat and/or tachyonic directions. One-loop corrections to the Kähler potential and gaugino condensation are presented as suitable tools for moduli stabilization to be discussed in subsequent work. Turning to the RS-like models, we obtain a master formula for the Kähler potential for an arbitrary number of vector and hyper moduli, which we evaluate exactly for special cases. Finally, we formulate the superfield description of 5D heterotic M-theory and obtain its effective 4D description for the universal ( h=1) case, in the presence of an arbitrary number of bulk 5-branes. We present, as a check of our expressions, time-dependent solutions of 4D heterotic M-theory, which uplift to 5D solutions generalizing the ones recently found in [W. Chen, Z.-W. Chong, G.W. Gibbons, H. Lü, C.N. Pope, Hořava-Witten stability: Eppur si muove, Nucl. Phys. B 732 (2006) 118, hep-th/0502077].

  8. 4D flow imaging with MRI

    PubMed Central

    Stankovic, Zoran; Allen, Bradley D.; Garcia, Julio; Jarvis, Kelly B.

    2014-01-01

    Magnetic resonance imaging (MRI) has become an important tool for the clinical evaluation of patients with cardiovascular disease. Since its introduction in the late 1980s, 2-dimensional phase contrast MRI (2D PC-MRI) has become a routine part of standard-of-care cardiac MRI for the assessment of regional blood flow in the heart and great vessels. More recently, time-resolved PC-MRI with velocity encoding along all three flow directions and three-dimensional (3D) anatomic coverage (also termed ‘4D flow MRI’) has been developed and applied for the evaluation of cardiovascular hemodynamics in multiple regions of the human body. 4D flow MRI allows for the comprehensive evaluation of complex blood flow patterns by 3D blood flow visualization and flexible retrospective quantification of flow parameters. Recent technical developments, including the utilization of advanced parallel imaging techniques such as k-t GRAPPA, have resulted in reasonable overall scan times, e.g., 8-12 minutes for 4D flow MRI of the aorta and 10-20 minutes for whole heart coverage. As a result, the application of 4D flow MRI in a clinical setting has become more feasible, as documented by an increased number of recent reports on the utility of the technique for the assessment of cardiac and vascular hemodynamics in patient studies. A number of studies have demonstrated the potential of 4D flow MRI to provide an improved assessment of hemodynamics which might aid in the diagnosis and therapeutic management of cardiovascular diseases. The purpose of this review is to describe the methods used for 4D flow MRI acquisition, post-processing and data analysis. In addition, the article provides an overview of the clinical applications of 4D flow MRI and includes a review of applications in the heart, thoracic aorta and hepatic system. PMID:24834414

  9. Confinement Driven by Scalar Field in 4d Non Abelian Gauge Theories

    SciTech Connect

    Chabab, Mohamed

    2007-01-12

    We review some of the most recent work on confinement in 4d gauge theories with a massive scalar field (dilaton). Emphasis is put on the derivation of confining analytical solutions to the Coulomb problem versus dilaton effective couplings to gauge terms. It is shown that these effective theories can be relevant to model quark confinement and may shed some light on confinement mechanism. Moreover, the study of interquark potential, derived from Dick Model, in the heavy meson sector proves that phenomenological investigation of tmechanism is more than justified and deserves more efforts.

  10. 4D DSA reconstruction using tomosynthesis projections

    NASA Astrophysics Data System (ADS)

    Buehler, Marc; Slagowski, Jordan M.; Mistretta, Charles A.; Strother, Charles M.; Speidel, Michael A.

    2017-03-01

    We investigate the use of tomosynthesis in 4D DSA to improve the accuracy of reconstructed vessel time-attenuation curves (TACs). It is hypothesized that a narrow-angle tomosynthesis dataset for each time point can be exploited to reduce artifacts caused by vessel overlap in individual projections. 4D DSA reconstructs time-resolved 3D angiographic volumes from a typical 3D DSA scan consisting of mask and iodine-enhanced C-arm rotations. Tomosynthesis projections are obtained either from a conventional C-arm rotation, or from an inverse geometry scanning-beam digital x-ray (SBDX) system. In the proposed method, rays of the tomosynthesis dataset which pass through multiple vessels can be ignored, allowing the non-overlapped rays to impart temporal information to the 4D DSA. The technique was tested in simulated scans of 2 mm diameter vessels separated by 2 to 5 cm, with TACs following either early or late enhancement. In standard 4D DSA, overlap artifacts were clearly present. Use of tomosynthesis projections in 4D DSA reduced TAC artifacts caused by vessel overlap, when a sufficient fraction of non-overlapped rays was available in each time frame. In cases where full overlap between vessels occurred, information could be recovered via a proposed image space interpolation technique. SBDX provides a tomosynthesis scan for each frame period in a rotational acquisition, whereas a standard C-arm geometry requires the grouping of multiple frames.

  11. GL4D: a GPU-based architecture for interactive 4D visualization.

    PubMed

    Chu, Alan; Fu, Chi-Wing; Hanson, Andrew J; Heng, Pheng-Ann

    2009-01-01

    This paper describes GL4D, an interactive system for visualizing 2-manifolds and 3-manifolds embedded in four Euclidean dimensions and illuminated by 4D light sources. It is a tetrahedron-based rendering pipeline that projects geometry into volume images, an exact parallel to the conventional triangle-based rendering pipeline for 3D graphics. Novel features include GPU-based algorithms for real-time 4D occlusion handling and transparency compositing; we thus enable a previously impossible level of quality and interactivity for exploring lit 4D objects. The 4D tetrahedrons are stored in GPU memory as vertex buffer objects, and the vertex shader is used to perform per-vertex 4D modelview transformations and 4D-to-3D projection. The geometry shader extension is utilized to slice the projected tetrahedrons and rasterize the slices into individual 2D layers of voxel fragments. Finally, the fragment shader performs per-voxel operations such as lighting and alpha blending with previously computed layers. We account for 4D voxel occlusion along the 4D-to-3D projection ray by supporting a multi-pass back-to-front fragment composition along the projection ray; to accomplish this, we exploit a new adaptation of the dual depth peeling technique to produce correct volume image data and to simultaneously render the resulting volume data using 3D transfer functions into the final 2D image. Previous CPU implementations of the rendering of 4D-embedded 3-manifolds could not perform either the 4D depth-buffered projection or manipulation of the volume-rendered image in real-time; in particular, the dual depth peeling algorithm is a novel GPU-based solution to the real-time 4D depth-buffering problem. GL4D is implemented as an integrated OpenGL-style API library, so that the underlying shader operations are as transparent as possible to the user.

  12. Semaphorin 4D Promotes Skeletal Metastasis in Breast Cancer

    PubMed Central

    Yang, Ying-Hua; Buhamrah, Asma; Schneider, Abraham; Lin, Yi-Ling; Zhou, Hua; Bugshan, Amr; Basile, John R.

    2016-01-01

    Bone density is controlled by interactions between osteoclasts, which resorb bone, and osteoblasts, which deposit it. The semaphorins and their receptors, the plexins, originally shown to function in the immune system and to provide chemotactic cues for axon guidance, are now known to play a role in this process as well. Emerging data have identified Semaphorin 4D (Sema4D) as a product of osteoclasts acting through its receptor Plexin-B1 on osteoblasts to inhibit their function, tipping the balance of bone homeostasis in favor of resorption. Breast cancers and other epithelial malignancies overexpress Sema4D, so we theorized that tumor cells could be exploiting this pathway to establish lytic skeletal metastases. Here, we use measurements of osteoblast and osteoclast differentiation and function in vitro and a mouse model of skeletal metastasis to demonstrate that both soluble Sema4D and protein produced by the breast cancer cell line MDA-MB-231 inhibits differentiation of MC3T3 cells, an osteoblast cell line, and their ability to form mineralized tissues, while Sema4D-mediated induction of IL-8 and LIX/CXCL5, the murine homologue of IL-8, increases osteoclast numbers and activity. We also observe a decrease in the number of bone metastases in mice injected with MDA-MB-231 cells when Sema4D is silenced by RNA interference. These results are significant because treatments directed at suppression of skeletal metastases in bone-homing malignancies usually work by arresting bone remodeling, potentially leading to skeletal fragility, a significant problem in patient management. Targeting Sema4D in these cancers would not affect bone remodeling and therefore could elicit an improved therapeutic result without the debilitating side effects. PMID:26910109

  13. Semaphorin 4D Promotes Skeletal Metastasis in Breast Cancer.

    PubMed

    Yang, Ying-Hua; Buhamrah, Asma; Schneider, Abraham; Lin, Yi-Ling; Zhou, Hua; Bugshan, Amr; Basile, John R

    2016-01-01

    Bone density is controlled by interactions between osteoclasts, which resorb bone, and osteoblasts, which deposit it. The semaphorins and their receptors, the plexins, originally shown to function in the immune system and to provide chemotactic cues for axon guidance, are now known to play a role in this process as well. Emerging data have identified Semaphorin 4D (Sema4D) as a product of osteoclasts acting through its receptor Plexin-B1 on osteoblasts to inhibit their function, tipping the balance of bone homeostasis in favor of resorption. Breast cancers and other epithelial malignancies overexpress Sema4D, so we theorized that tumor cells could be exploiting this pathway to establish lytic skeletal metastases. Here, we use measurements of osteoblast and osteoclast differentiation and function in vitro and a mouse model of skeletal metastasis to demonstrate that both soluble Sema4D and protein produced by the breast cancer cell line MDA-MB-231 inhibits differentiation of MC3T3 cells, an osteoblast cell line, and their ability to form mineralized tissues, while Sema4D-mediated induction of IL-8 and LIX/CXCL5, the murine homologue of IL-8, increases osteoclast numbers and activity. We also observe a decrease in the number of bone metastases in mice injected with MDA-MB-231 cells when Sema4D is silenced by RNA interference. These results are significant because treatments directed at suppression of skeletal metastases in bone-homing malignancies usually work by arresting bone remodeling, potentially leading to skeletal fragility, a significant problem in patient management. Targeting Sema4D in these cancers would not affect bone remodeling and therefore could elicit an improved therapeutic result without the debilitating side effects.

  14. Combined convective and diffusive simulations: VERB-4D comparison with 17 March 2013 Van Allen Probes observations: VERB-4D

    DOE PAGES

    Shprits, Yuri Y.; Kellerman, Adam C.; Drozdov, Alexander Y.; ...

    2015-11-19

    Our study focused on understanding the coupling between different electron populations in the inner magnetosphere and the various physical processes that determine evolution of electron fluxes at different energies. Observations during the 17 March 2013 storm and simulations with a newly developed Versatile Electron Radiation Belt-4D (VERB-4D) are presented. This analysis of the drift trajectories of the energetic and relativistic electrons shows that electron trajectories at transitional energies with a first invariant on the scale of ~100 MeV/G may resemble ring current or relativistic electron trajectories depending on the level of geomagnetic activity. Simulations with the VERB-4D code including convection,more » radial diffusion, and energy diffusion are presented. Sensitivity simulations including various physical processes show how different acceleration mechanisms contribute to the energization of energetic electrons at transitional energies. In particular, the range of energies where inward transport is strongly influenced by both convection and radial diffusion are studied. Our results of the 4-D simulations are compared to Van Allen Probes observations at a range of energies including source, seed, and core populations of the energetic and relativistic electrons in the inner magnetosphere.« less

  15. Combined convective and diffusive simulations: VERB-4D comparison with 17 March 2013 Van Allen Probes observations: VERB-4D

    SciTech Connect

    Shprits, Yuri Y.; Kellerman, Adam C.; Drozdov, Alexander Y.; Spence, Harlan E.; Reeves, Geoffrey D.; Baker, Daniel N.

    2015-11-19

    Our study focused on understanding the coupling between different electron populations in the inner magnetosphere and the various physical processes that determine evolution of electron fluxes at different energies. Observations during the 17 March 2013 storm and simulations with a newly developed Versatile Electron Radiation Belt-4D (VERB-4D) are presented. This analysis of the drift trajectories of the energetic and relativistic electrons shows that electron trajectories at transitional energies with a first invariant on the scale of ~100 MeV/G may resemble ring current or relativistic electron trajectories depending on the level of geomagnetic activity. Simulations with the VERB-4D code including convection, radial diffusion, and energy diffusion are presented. Sensitivity simulations including various physical processes show how different acceleration mechanisms contribute to the energization of energetic electrons at transitional energies. In particular, the range of energies where inward transport is strongly influenced by both convection and radial diffusion are studied. Our results of the 4-D simulations are compared to Van Allen Probes observations at a range of energies including source, seed, and core populations of the energetic and relativistic electrons in the inner magnetosphere.

  16. Shadow-driven 4D haptic visualization.

    PubMed

    Zhang, Hui; Hanson, Andrew

    2007-01-01

    Just as we can work with two-dimensional floor plans to communicate 3D architectural design, we can exploit reduced-dimension shadows to manipulate the higher-dimensional objects generating the shadows. In particular, by taking advantage of physically reactive 3D shadow-space controllers, we can transform the task of interacting with 4D objects to a new level of physical reality. We begin with a teaching tool that uses 2D knot diagrams to manipulate the geometry of 3D mathematical knots via their projections; our unique 2D haptic interface allows the user to become familiar with sketching, editing, exploration, and manipulation of 3D knots rendered as projected imageson a 2D shadow space. By combining graphics and collision-sensing haptics, we can enhance the 2D shadow-driven editing protocol to successfully leverage 2D pen-and-paper or blackboard skills. Building on the reduced-dimension 2D editing tool for manipulating 3D shapes, we develop the natural analogy to produce a reduced-dimension 3D tool for manipulating 4D shapes. By physically modeling the correct properties of 4D surfaces, their bending forces, and their collisions in the 3D haptic controller interface, we can support full-featured physical exploration of 4D mathematical objects in a manner that is otherwise far beyond the experience accessible to human beings. As far as we are aware, this paper reports the first interactive system with force-feedback that provides "4D haptic visualization" permitting the user to model and interact with 4D cloth-like objects.

  17. 2,4-D and IAA Amino Acid Conjugates Show Distinct Metabolism in Arabidopsis

    PubMed Central

    Eyer, Luděk; Vain, Thomas; Pařízková, Barbora; Oklestkova, Jana; Barbez, Elke; Kozubíková, Hana; Pospíšil, Tomáš; Wierzbicka, Roksana; Kleine-Vehn, Jürgen; Fránek, Milan; Strnad, Miroslav; Robert, Stéphanie

    2016-01-01

    The herbicide 2,4-D exhibits an auxinic activity and therefore can be used as a synthetic and traceable analog to study auxin-related responses. Here we identified that not only exogenous 2,4-D but also its amide-linked metabolite 2,4-D-Glu displayed an inhibitory effect on plant growth via the TIR1/AFB auxin-mediated signaling pathway. To further investigate 2,4-D metabolite conversion, identity and activity, we have developed a novel purification procedure based on the combination of ion exchange and immuno-specific sorbents combined with a sensitive liquid chromatography-mass spectrometry method. In 2,4-D treated samples, 2,4-D-Glu and 2,4-D-Asp were detected at 100-fold lower concentrations compared to 2,4-D levels, showing that 2,4-D can be metabolized in the plant. Moreover, 2,4-D-Asp and 2,4-D-Glu were identified as reversible forms of 2,4-D homeostasis that can be converted to free 2,4-D. This work paves the way to new studies of auxin action in plant development. PMID:27434212

  18. Modeling robust QSAR 3: SOM-4D-QSAR with iterative variable elimination IVE-PLS: application to steroid, azo dye, and benzoic acid series.

    PubMed

    Bak, Andrzej; Polanski, Jaroslaw

    2007-01-01

    In the current paper we present a receptor-independent 4D-QSAR method based on self-organizing mapping (SOM-4D-QSAR) and in particular focus on its pharmacophore mapping ability. We use a novel stochastic procedure to verify the predictive ability of the method for a large population of 4D-QSAR models generated. This systematic study was conducted on a series of benzoic acids, azo dyes, and steroids that bind aromatase. We show that the 4D-QSAR method coupled with IVE-PLS provides a very stable and predictive modeling technique. The method enables us to identify the molecular motifs contributing the most to the fiber-dye affinity and the aromatase enzyme binding activity of the steroid. However, the method appeared much less effective for the benzoic acid series, in which the efficacy was limited by electronic effects strictly correlated to a single conformer.

  19. 4D-Var Developement at GMAO

    NASA Technical Reports Server (NTRS)

    Pelc, Joanna S.; Todling, Ricardo; Akkraoui, Amal El

    2014-01-01

    The Global Modeling and Assimilation Offce (GMAO) is currently using an IAU-based 3D-Var data assimilation system. GMAO has been experimenting with a 3D-Var-hybrid version of its data assimilation system (DAS) for over a year now, which will soon become operational and it will rapidly progress toward a 4D-EnVar. Concurrently, the machinery to exercise traditional 4DVar is in place and it is desirable to have a comparison of the traditional 4D approach with the other available options, and evaluate their performance in the Goddard Earth Observing System (GEOS) DAS. This work will also explore the possibility for constructing a reduced order model (ROM) to make traditional 4D-Var computationally attractive for increasing model resolutions. Part of the research on ROM will be to search for a suitably acceptable space to carry on the corresponding reduction. This poster illustrates how the IAU-based 4D-Var assimilation compares with our currently used IAU-based 3D-Var.

  20. Theoretical constraints on the Higgs effective couplings.

    SciTech Connect

    Low, I.; Rattazzi, R.; Vichi, A.; High Energy Physics; Northwestern Univ; EPFL

    2010-04-01

    We derive constraints on the sign of couplings in an effective Higgs Lagrangian using prime principles such as the naturalness principle, global symmetries, and unitarity. Specifically, we study four dimension-six operators, {Omicron}{sub H}, {Omicron}{sub y}, {Omicron}{sub g}, and {Omicron}{sub {gamma}} which contribute to the production and decay of the Higgs boson at the Large Hadron Collider (LHC), among other things. Assuming the Higgs is a fundamental scalar, we find: (1) the coefficient of {Omicron}{sub H} is positive except when there are triplet scalars, resulting in a reduction in the Higgs on-shell coupling from their standard model (SM) expectations if no other operators contribute, (2) the linear combination of {Omicron}{sub H} and {Omicron}{sub y} controlling the overall Higgs coupling to fermion is always reduced, (3) the sign of {Omicron}{sub g} induced by a new colored fermion is such that it interferes destructively with the SM top contribution in the gluon fusion production of the Higgs, if the new fermion cancels the top quadratic divergence in the Higgs mass, and (4) the correlation between naturalness and the sign of {Omicron}{sub {gamma}} is similar to that of {Omicron}{sub g}, when there is a new set of heavy electroweak gauge bosons. Next considering a composite scalar for the Higgs, we find the reduction in the on-shell Higgs couplings persists. If further assuming a collective breaking mechanism as in little Higgs theories, the coefficient of {Omicron}{sub H} remains positive even in the presence of triplet scalars. In the end, we conclude that the gluon fusion production of the Higgs boson is reduced from the SM rate in all composite Higgs models. Our study suggests a wealth of information could be revealed by precise measurements of the Higgs couplings, providing strong motivations for both improving on measurements at the LHC and building a precision machine such as the linear collider.

  1. Mapping motion from 4D-MRI to 3D-CT for use in 4D dose calculations: A technical feasibility study

    SciTech Connect

    Boye, Dirk; Lomax, Tony; Knopf, Antje

    2013-06-15

    variable breathing patterns to show the effect of possible irregular breathing on active scanned proton therapy. Using a 4D-CT(MRI), including motion irregularities, resulted in significantly different proton dose distributions. Conclusions: The authors have demonstrated that motion information from 4D-MRI can be used to generate realistic 4D-CT data sets on the basis of a single static 3D-CT data set. 4D-CT(MRI) presents a novel approach to test the robustness of treatment plans in the circumstance of patient motion.

  2. 3D/4D sonography - any safety problem.

    PubMed

    Pooh, Ritsuko K; Maeda, Kazuo; Kurjak, Asim; Sen, Cihat; Ebrashy, Alaa; Adra, Abdallah; Dayyabu, Aliyu Labaran; Wataganara, Tuangsit; de Sá, Renato Augusto Moreira; Stanojevic, Milan

    2016-03-01

    Gray-scale image data are processed in 3D ultrasound by repeated scans of multiple planes within a few seconds to achieve one surface rendering image and three perpendicular plane images. The 4D image is achieved by repeating 3D images in short intervals, i.e. 3D and 4D ultrasound are based on simple B-mode images. During 3D/4D acquisition, a fetus in utero is exposed by ultrasound beam for only a few seconds, and it is as short as real-time B-mode scanning. Therefore, simple 3D imaging is as safe as a simple B-mode scan. The 4D ultrasound is also as safe as a simple B-mode scan, but the ultrasound exposure should be shorter than 30 min. The thermal index (TI) and mechanical index (MI) should both be lower than 1.0, and the ultrasound study is regulated by the Doppler ultrasound if it is combined with simple 3D or 4D ultrasound. Recently, some articles have reported the functional changes of animal fetal brain neuronal cells and liver cell apoptosis with Doppler ultrasound. We discuss cell apoptosis by ultrasound in this report. Diagnostic ultrasound safety is achieved by controlling the output pulse and continuous ultrasound waves using thermal and mechanical indices, which should be <1.0 in abdominal and transvaginal scan, pulsed Doppler, as well as 3D and 4D ultrasound. The lowest spatial peak temporal average (SPTA) intensity of the ultrasound to suppress cultured cell growth is 240 mW/cm2, below which no ultrasound effect has been reported. An ultrasound user must be trained to recognize the ultrasound bioeffects; thermal and mechanical indices, and how to reduce these when they are higher than 1.0 on the monitor display; and guide the proper use of the ultrasound under the ALARA principle, because the user is responsible for ensuring ultrasound safety.

  3. 2,4-D removal via denitrification using volatile fatty acids.

    PubMed

    He, X; Wareham, D G

    2011-01-01

    Many countries have waters contaminated with both herbicides and nitrates; however, information is limited with respect to removal rates for combined nitrate and herbicide elimination. This research investigates the removal of 2,4-D via denitrification, with a particular emphasis on the effect of adding naturally generated volatile fatty acids (VFAs). The acids were produced from an acid-phase anaerobic digester with a mean VFA concentration of 3153±801 mg/L (as acetic acid). Initially, 2,4-D degrading bacteria were developed in an SBR fed with both sewage and 2,4-D (30-100 mg/L). Subsequent denitrification batch tests demonstrated that the specific denitrification rate increased from 0.0119±0.0039 using 2,4-D alone to 0.0192±0.0079 g NO₃-N/g VSS per day, when 2,4-D was combined with natural VFAs from the digester. Similarly, the specific 2,4-D consumption rate increased from 0.0016±0.0009 using 2,4-D alone to 0.0055±0.0021 g 2,4-D/g VSS per day, when using 2,4-D plus natural VFAs. Finally, a parallel increase in the percent 2,4-D removal was observed, rising from 28.33±11.88 using 2,4-D alone to 54.17±21.89 using 2,4-D plus natural VFAs.

  4. Interactive animation of 4D performance capture.

    PubMed

    Casas, Dan; Tejera, Margara; Guillemaut, Jean-Yves; Hilton, Adrian

    2013-05-01

    A 4D parametric motion graph representation is presented for interactive animation from actor performance capture in a multiple camera studio. The representation is based on a 4D model database of temporally aligned mesh sequence reconstructions for multiple motions. High-level movement controls such as speed and direction are achieved by blending multiple mesh sequences of related motions. A real-time mesh sequence blending approach is introduced, which combines the realistic deformation of previous nonlinear solutions with efficient online computation. Transitions between different parametric motion spaces are evaluated in real time based on surface shape and motion similarity. Four-dimensional parametric motion graphs allow real-time interactive character animation while preserving the natural dynamics of the captured performance.

  5. Digit ratio (2D:4D) in homosexual and heterosexual men from Austria.

    PubMed

    Voracek, Martin; Manning, John T; Ponocny, Ivo

    2005-06-01

    Neurohormonal theories of sexual orientation emphasize the organizational effects of testosterone on the developing brain. A recent suggestion, that the ratio of the length of the 2nd and 4th digits (2D:4D) is negatively correlated with prenatal testosterone, has led to a number of studies of 2D:4D in homosexual and heterosexual men and women. The results have been mixed. In comparison to heterosexual men, mean 2D:4D in gay men has been reported to be hypermasculinized (lower 2D:4D), hypomasculinized (higher 2D:4D), or to show no significant difference. Here, we report mean 2D:4D in Austrian homosexual and heterosexual men. We found no significant difference between means for homosexual and heterosexual 2D:4D, with values for both falling between 0.96 to 0.97. There are now 6 reports of 2D:4D in heterosexual and homosexual men. Considering Caucasian men, the studies from the United States show low heterosexual mean 2D:4D, and homosexual mean 2D:4D is higher or similar to that of heterosexuals. The European studies show high heterosexual mean 2D:4D, and comparisons with homosexuals reveal the latter to have lower or similar mean 2D:4D to that of heterosexuals. We discuss these results in relation to the suggestion that mean 2D:4D in heterosexual men differs across populations but mean 2D:4D in homosexuals shows less geographical variation (the "uniform mean hypothesis"). It is concluded that more data are required to clarify whether or not there is a 2D:4D effect for sexual orientation in men.

  6. 4D CT lung ventilation images are affected by the 4D CT sorting method

    PubMed Central

    Yamamoto, Tokihiro; Kabus, Sven; Lorenz, Cristian; Johnston, Eric; Maxim, Peter G.; Diehn, Maximilian; Eclov, Neville; Barquero, Cristian; Loo, Billy W.; Keall, Paul J.

    2013-01-01

    Purpose: Four-dimensional (4D) computed tomography (CT) ventilation imaging is a novel promising technique for lung functional imaging. The current standard 4D CT technique using phase-based sorting frequently results in artifacts, which may deteriorate the accuracy of ventilation imaging. The purpose of this study was to quantify the variability of 4D CT ventilation imaging due to 4D CT sorting. Methods: 4D CT image sets from nine lung cancer patients were each sorted by the phase-based method and anatomic similarity-based method, designed to reduce artifacts, with corresponding ventilation images created for each method. Artifacts in the resulting 4D CT images were quantified with the artifact score which was defined based on the difference between the normalized cross correlation for CT slices within a CT data segment and that for CT slices bordering the interface between adjacent CT data segments. The ventilation variation was quantified using voxel-based Spearman rank correlation coefficients for all lung voxels, and Dice similarity coefficients (DSC) for the spatial overlap of low-functional lung volumes. Furthermore, the correlations with matching single-photon emission CT (SPECT) ventilation images (assumed ground truth) were evaluated for three patients to investigate which sorting method provides higher physiologic accuracy. Results: Anatomic similarity-based sorting reduced 4D CT artifacts compared to phase-based sorting (artifact score, 0.45 ± 0.14 vs 0.58 ± 0.24, p = 0.10 at peak-exhale; 0.63 ± 0.19 vs 0.71 ± 0.31, p = 0.25 at peak-inhale). The voxel-based correlation between the two ventilation images was 0.69 ± 0.26 on average, ranging from 0.03 to 0.85. The DSC was 0.71 ± 0.13 on average. Anatomic similarity-based sorting yielded significantly fewer lung voxels with paradoxical negative ventilation values than phase-based sorting (5.0 ± 2.6% vs 9.7 ± 8.4%, p = 0.05), and improved the correlation with SPECT ventilation regionally. Conclusions

  7. Evaluation of a novel 4D in vivo dosimetry system

    SciTech Connect

    Cherpak, A.; Ding, W.; Hallil, A.; Cygler, J. E.

    2009-05-15

    A prototype of a new 4D in vivo dosimetry system capable of simultaneous real-time position monitoring and dose measurement has been developed. The radiation positioning system (RADPOS) is controlled by a computer and combines two technologies: MOSFET radiation detector coupled with an electromagnetic positioning device. Special software has been developed that allows sampling position and dose either manually or automatically in user-defined time intervals. Preliminary tests of the new device include a dosimetric evaluation of the detector in {sup 60}Co, 6 MV, and 18 MV beams and measurements of spatial position stability and accuracy. In addition, the effect of metals and other materials on the performance of the positioning system has been investigated. Results show that the RADPOS system can measure in-air dose profiles that agree, on average, within 3%-5% of diode measurements for the energies tested. The response of the detector is isotropic within 1.6% (1 SD) with a maximum deviation of {+-}4.0% over 360 deg. The maximum variation in the calibration coefficient over field sizes from 6x6 to 25x25 cm{sup 2} was 2.3% for RADPOS probe with the high sensitivity MOSFET and 4.6% for the probe with the standard sensitivity MOSFET. Of the materials tested, only aluminum, lead, and brass caused shifts in the RADPOS read position. The magnitude of the shift varied between materials and size of the material sample. Nonmagnetic stainless steel (Grade 304) caused a distortion of less than 2 mm when placed within 10 mm of the detector; therefore, it can provide a reasonable alternative to other metals if required. The results of the preliminary tests indicate that the device can be used for in vivo dosimetry in {sup 60}Co and high-energy beams from linear accelerators.

  8. Detection of 2,4-dichlorophenoxyacetic acid (2,4-D) residues in neonates breast-fed by 2,4-D exposed dams.

    PubMed

    Stürtz, N; Evangelista de Duffard, A M; Duffard, R

    2000-01-01

    Knowing early nutritional status have been shown to be an important factor in determining the activity level of rats later in life, we studied offspring of dams which had received 50, 70 or 700 mg/kg of 2,4-Dichlorophenoxyacetic acid (2,4-D) during nursing. Neonatal tissues and the stomach content (milk) were examined up to 16 post natal days to detect body and organs weight alterations and 2,4-D residues after 2,4-D maternal dosing every-other-day, from post natal day 1. We detected 2,4-D residues in stomach content, blood, brain and kidney of 4-day-old neonates breast-fed by 2,4-D exposed mothers and onward. 2,4-D residues were dose- and exposure-time-dependent. The highest dose impaired body growth, as well as low tissue weights and diminished stomach contents. Levels of 2,4-D residues in stomach content, blood, kidney and brain of post natal rats (age PD 4-PD 16) fed through lactation from dams treated with 2,4-D demonstrated that 2,4-D was transferred to the neonates and the diminished body and tissues weight during this developmental period could be due to a diminished milk intake or/and to the direct 2,4-D toxic effect. Besides, when the herbicide treatment (100 mg 2,4-D/kg) was withdrawn from the dams, 2,4-D residues remained in the stomach content of neonates for at least one week. This fact indicated that dams continued depurating the herbicide through their milk.

  9. Digit ratio (2D:4D) and sprinting speed in boys.

    PubMed

    Manning, J T; Hill, M R

    2009-01-01

    Digit ratio (2D:4D), a putative correlate of prenatal testosterone, has been found to relate to performance in sport and athletics such that low 2D:4D (high prenatal testosterone) correlates with high performance. Speed in endurance races is strongly related to 2D:4D, and may be one factor that underlies the link between sport and 2D:4D, but nothing is known of the relationship between 2D:4D and sprinting speed. Here we show that running times over 50 m were positively correlated with 2D:4D in a sample of 241 boys (i.e. runners with low 2D:4D ran faster than runners with high 2D:4D). The relationship was also found for 50 m split times (at 20, 30, and 40 m) and was independent of age, BMI, and an index of maturity. However, associations between 2D:4D and sprinting speed were much weaker than those reported for endurance running. This suggests that 2D:4D is a relatively weak predictor of strength and a stronger predictor of efficiency in aerobic exercise. We discuss the effect sizes for relationships between 2D:4D and sport and target traits in general, and identify areas of strength and weakness in digit ratio research.

  10. 4D MR imaging using robust internal respiratory signal

    NASA Astrophysics Data System (ADS)

    Hui, CheukKai; Wen, Zhifei; Stemkens, Bjorn; Tijssen, R. H. N.; van den Berg, C. A. T.; Hwang, Ken-Pin; Beddar, Sam

    2016-05-01

    The purpose of this study is to investigate the feasibility of using internal respiratory (IR) surrogates to sort four-dimensional (4D) magnetic resonance (MR) images. The 4D MR images were constructed by acquiring fast 2D cine MR images sequentially, with each slice scanned for more than one breathing cycle. The 4D volume was then sorted retrospectively using the IR signal. In this study, we propose to use multiple low-frequency components in the Fourier space as well as the anterior body boundary as potential IR surrogates. From these potential IR surrogates, we used a clustering algorithm to identify those that best represented the respiratory pattern to derive the IR signal. A study with healthy volunteers was performed to assess the feasibility of the proposed IR signal. We compared this proposed IR signal with the respiratory signal obtained using respiratory bellows. Overall, 99% of the IR signals matched the bellows signals. The average difference between the end inspiration times in the IR signal and bellows signal was 0.18 s in this cohort of matching signals. For the acquired images corresponding to the other 1% of non-matching signal pairs, the respiratory motion shown in the images was coherent with the respiratory phases determined by the IR signal, but not the bellows signal. This suggested that the IR signal determined by the proposed method could potentially correct the faulty bellows signal. The sorted 4D images showed minimal mismatched artefacts and potential clinical applicability. The proposed IR signal therefore provides a feasible alternative to effectively sort MR images in 4D.

  11. Dynamic nonlinear thermal optical effects in coupled ring resonators

    NASA Astrophysics Data System (ADS)

    Huang, Chenguang; Fan, Jiahua; Zhu, Lin

    2012-09-01

    We investigate the dynamic nonlinear thermal optical effects in a photonic system of two coupled ring resonators. A bus waveguide is used to couple light in and out of one of the coupled resonators. Based on the coupling from the bus to the resonator, the coupling between the resonators and the intrinsic loss of each individual resonator, the system transmission spectrum can be classified by three different categories: coupled-resonator-induced absorption, coupled-resonator-induced transparency and over coupled resonance splitting. Dynamic thermal optical effects due to linear absorption have been analyzed for each category as a function of the input power. The heat power in each resonator determines the thermal dynamics in this coupled resonator system. Multiple "shark fins" and power competition between resonators can be foreseen. Also, the nonlinear absorption induced thermal effects have been discussed.

  12. 4D electron microscopy: principles and applications.

    PubMed

    Flannigan, David J; Zewail, Ahmed H

    2012-10-16

    achievable with short intense pulses containing a large number of electrons, however, are limited to tens of nanometers and nanoseconds, respectively. This is because Coulomb repulsion is significant in such a pulse, and the electrons spread in space and time, thus limiting the beam coherence. It is therefore not possible to image the ultrafast elementary dynamics of complex transformations. The challenge was to retain the high spatial resolution of a conventional TEM while simultaneously enabling the temporal resolution required to visualize atomic-scale motions. In this Account, we discuss the development of four-dimensional ultrafast electron microscopy (4D UEM) and summarize techniques and applications that illustrate the power of the approach. In UEM, images are obtained either stroboscopically with coherent single-electron packets or with a single electron bunch. Coulomb repulsion is absent under the single-electron condition, thus permitting imaging, diffraction, and spectroscopy, all with high spatiotemporal resolution, the atomic scale (sub-nanometer and femtosecond). The time resolution is limited only by the laser pulse duration and energy carried by the electron packets; the CCD camera has no bearing on the temporal resolution. In the regime of single pulses of electrons, the temporal resolution of picoseconds can be attained when hundreds of electrons are in the bunch. The applications given here are selected to highlight phenomena of different length and time scales, from atomic motions during structural dynamics to phase transitions and nanomechanical oscillations. We conclude with a brief discussion of emerging methods, which include scanning ultrafast electron microscopy (S-UEM), scanning transmission ultrafast electron microscopy (ST-UEM) with convergent beams, and time-resolved imaging of biological structures at ambient conditions with environmental cells.

  13. Active origami by 4D printing

    NASA Astrophysics Data System (ADS)

    Ge, Qi; Dunn, Conner K.; Qi, H. Jerry; Dunn, Martin L.

    2014-09-01

    Recent advances in three dimensional (3D) printing technology that allow multiple materials to be printed within each layer enable the creation of materials and components with precisely controlled heterogeneous microstructures. In addition, active materials, such as shape memory polymers, can be printed to create an active microstructure within a solid. These active materials can subsequently be activated in a controlled manner to change the shape or configuration of the solid in response to an environmental stimulus. This has been termed 4D printing, with the 4th dimension being the time-dependent shape change after the printing. In this paper, we advance the 4D printing concept to the design and fabrication of active origami, where a flat sheet automatically folds into a complicated 3D component. Here we print active composites with shape memory polymer fibers precisely printed in an elastomeric matrix and use them as intelligent active hinges to enable origami folding patterns. We develop a theoretical model to provide guidance in selecting design parameters such as fiber dimensions, hinge length, and programming strains and temperature. Using the model, we design and fabricate several active origami components that assemble from flat polymer sheets, including a box, a pyramid, and two origami airplanes. In addition, we directly print a 3D box with active composite hinges and program it to assume a temporary flat shape that subsequently recovers to the 3D box shape on demand.

  14. Supercurrent anomalies in 4d SCFTs

    NASA Astrophysics Data System (ADS)

    Papadimitriou, Ioannis

    2017-07-01

    We use holographic renormalization of minimal N=2 gauged supergravity in order to derive the general form of the quantum Ward identities for 3d N=2 and 4d N=1 superconformal theories on general curved backgrounds, including an arbitrary fermionic source for the supercurrent. The Ward identities for 4d N=1 theories contain both bosonic and fermionic global anomalies, which we determine explicitly up to quadratic order in the supercurrent source. The Ward identities we derive apply to any superconformal theory, independently of whether it admits a holographic dual, except for the specific values of the a and c anomaly coefficients, which are equal due to our starting point of a two-derivative bulk supergravity theory. We show that the fermionic anomalies lead to an anomalous transformation of the supercurrent under rigid supersymmetry on backgrounds admitting Killing spinors, even if all superconformal anomalies are numerically zero on such backgrounds. The anomalous transformation of the supercurrent under rigid supersymmetry leads to an obstruction to the Q-exactness of the stress tensor in supersymmetric vacua, and may have implications for the applicability of localization techniques. We use this obstruction to the Q-exactness of the stress tensor, together with the Ward identities, in order to determine the general form of the stress tensor and R-current one-point functions in supersymmetric vacua, which allows us to obtain general expressions for the supersymmetric Casimir charges and partition function.

  15. 4D geomorphological evolution of intertropical islands

    NASA Astrophysics Data System (ADS)

    Pastier, Anne-Morwenn; Bezos, Antoine; Husson, Laurent; Pedoja, Kevin; Arias, Camilo; Elliot, Mary; Lacroix, Pascal; Imran, Andi Muhammad

    2017-04-01

    Coral reef terraces record joint variations of sea level and surface elevation. U/Th ratings on corals along with topographic/bathymetric profiles and eustatic reconstitutions allow to locally determine the vertical rate of ground motion, while numerical modelling of reef sequences allows to unravel the processes controlling the architecture of sequences, and high-resolution DEMs facilitates the detailed mapping of the sequences of reef terraces. Alltogether, these methods allow to extrapolate the local vertical rates towards an unprecedented resolution for 4D kinematics. We applied our method to uplifting islands of the tectonically active Buton Archipelago, SE Sulawesi, Indonesia. The area undergoes a general uplift revealed by the ubiquitous occurrence of uplifted and folded reef sequences. We dated some 40 samples using U/Th, acquired sonar and dGPS profiles, and constructed high-res DEMs (Pleiades). Local vertical rates (from 0.2 to 0.28 mm/yr) were determined. Detailed geomorphological mapping of the lateral variations of the terraces are converted into time and space variations of uplift rates. Extrapolating the higher, undated terraces permits to reconstruct the overall 4D geomorphology history over the last Ma. In turns, these results give a unique view on the structural kinematics.

  16. SEMA4D compromises blood-brain barrier, activates microglia, and inhibits remyelination in neurodegenerative disease.

    PubMed

    Smith, Ernest S; Jonason, Alan; Reilly, Christine; Veeraraghavan, Janaki; Fisher, Terrence; Doherty, Michael; Klimatcheva, Ekaterina; Mallow, Crystal; Cornelius, Chad; Leonard, John E; Marchi, Nicola; Janigro, Damir; Argaw, Azeb Tadesse; Pham, Trinh; Seils, Jennifer; Bussler, Holm; Torno, Sebold; Kirk, Renee; Howell, Alan; Evans, Elizabeth E; Paris, Mark; Bowers, William J; John, Gareth; Zauderer, Maurice

    2015-01-01

    Multiple sclerosis (MS) is a chronic neuroinflammatory disease characterized by immune cell infiltration of CNS, blood-brain barrier (BBB) breakdown, localized myelin destruction, and progressive neuronal degeneration. There exists a significant need to identify novel therapeutic targets and strategies that effectively and safely disrupt and even reverse disease pathophysiology. Signaling cascades initiated by semaphorin 4D (SEMA4D) induce glial activation, neuronal process collapse, inhibit migration and differentiation of oligodendrocyte precursor cells (OPCs), and disrupt endothelial tight junctions forming the BBB. To target SEMA4D, we generated a monoclonal antibody that recognizes mouse, rat, monkey and human SEMA4D with high affinity and blocks interaction between SEMA4D and its cognate receptors. In vitro, anti-SEMA4D reverses the inhibitory effects of recombinant SEMA4D on OPC survival and differentiation. In vivo, anti-SEMA4D significantly attenuates experimental autoimmune encephalomyelitis in multiple rodent models by preserving BBB integrity and axonal myelination and can be shown to promote migration of OPC to the site of lesions and improve myelin status following chemically-induced demyelination. Our study underscores SEMA4D as a key factor in CNS disease and supports the further development of antibody-based inhibition of SEMA4D as a novel therapeutic strategy for MS and other neurologic diseases with evidence of demyelination and/or compromise to the neurovascular unit.

  17. Dynamic aperture effects due to linear coupling

    SciTech Connect

    Parzen, G.

    1991-01-01

    The coupling introduced by the random a{sub 1} can produce considerable distortion of the betatron motion. For a given initial x{sub o}, x{sub o}{prime}, y{sub o}, y{sub o}{prime}, the maximum x and the maximum y for the subsequent motion can be considerably larger when coupling is present. The maximum x and y can be used as a measure of the betatron distortion. One effect of this betatron distortion shows up in the dynamic aperture, in a loss in the stability limit, A{sub SL}, found by tracking. The betatron distortion causes the particle to move further out in the magnets, where it sees stronger non-linear fields. Previous tracking showed a loss in A{sub SL} due to random a{sub 1} and b{sub 1}. It was noticed then that the loss in A{sub SL} was associated with a betatron motion distortion which was primarily a linear effect. For a given initial x, x{prime}, y, y{prime} the x{sub max} and y{sub max} in the high-{Beta} magnets were considerably larger for those random a{sub 1} distributions which produced the smaller A{sub SL}. The studies described in this report show that the stability limit, A{sub SL}, depends on the starting location around the ring. This variation in A{sub SL} around the ring can be correlated with the variation in the betatron distortion for particles starting at different places around the ring. It is proposed that the average of the A{sub SL} found by starting at each of the QF, the focusing quadrupoles in the arcs, can be taken as a measure of the dynamic aperture. It is found that the average A{sub SL} is reduced by about 15% by the random a{sub 1} multipoles expected in RHIC.

  18. Advances in 4D radiation therapy for managing respiration: part II - 4D treatment planning.

    PubMed

    Rosu, Mihaela; Hugo, Geoffrey D

    2012-12-01

    The development of 4D CT imaging technology made possible the creation of patient models that are reflective of respiration-induced anatomical changes by adding a temporal dimension to the conventional 3D, spatial-only, patient description. This had opened a new venue for treatment planning and radiation delivery, aimed at creating a comprehensive 4D radiation therapy process for moving targets. Unlike other breathing motion compensation strategies (e.g. breath-hold and gating techniques), 4D radiotherapy assumes treatment delivery over the entire respiratory cycle - an added bonus for both patient comfort and treatment time efficiency. The time-dependent positional and volumetric information holds the promise for optimal, highly conformal, radiotherapy for targets experiencing movements caused by respiration, with potentially elevated dose prescriptions and therefore higher cure rates, while avoiding the uninvolved nearby structures. In this paper, the current state of the 4D treatment planning is reviewed, from theory to the established practical routine. While the fundamental principles of 4D radiotherapy are well defined, the development of a complete, robust and clinically feasible process still remains a challenge, imposed by limitations in the available treatment planning and radiation delivery systems.

  19. Advances in 4D Radiation Therapy for Managing Respiration: Part II – 4D Treatment Planning

    PubMed Central

    Rosu, Mihaela; Hugo, Geoffrey D.

    2014-01-01

    The development of 4D CT imaging technology made possible the creation of patient models that are reflective of respiration-induced anatomical changes by adding a temporal dimension to the conventional 3D, spatial-only, patient description. This had opened a new venue for treatment planning and radiation delivery, aimed at creating a comprehensive 4D radiation therapy process for moving targets. Unlike other breathing motion compensation strategies (e.g. breath-hold and gating techniques), 4D radiotherapy assumes treatment delivery over the entire respiratory cycle – an added bonus for both patient comfort and treatment time efficiency. The time-dependent positional and volumetric information holds the promise for optimal, highly conformal, radiotherapy for targets experiencing movements caused by respiration, with potentially elevated dose prescriptions and therefore higher cure rates, while avoiding the uninvolved nearby structures. In this paper, the current state of the 4D treatment planning is reviewed, from theory to the established practical routine. While the fundamental principles of 4D radiotherapy are well defined, the development of a complete, robust and clinically feasible process still remains a challenge, imposed by limitations in the available treatment planning and radiation delivery systems. PMID:22796324

  20. Motion4D-library extended

    NASA Astrophysics Data System (ADS)

    Müller, Thomas

    2011-06-01

    The new version of the Motion4D-library now also includes the integration of a Sachs basis and the Jacobi equation to determine gravitational lensing of pointlike sources for arbitrary spacetimes.New version program summaryProgram title: Motion4D-libraryCatalogue identifier: AEEX_v3_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEEX_v3_0.htmlProgram obtainable from: CPC Program Library, Queen's University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 219 441No. of bytes in distributed program, including test data, etc.: 6 968 223Distribution format: tar.gzProgramming language: C++Computer: All platforms with a C++ compilerOperating system: Linux, WindowsRAM: 61 MbytesClassification: 1.5External routines: Gnu Scientic Library (GSL) (http://www.gnu.org/software/gsl/)Catalogue identifier of previous version: AEEX_v2_0Journal reference of previous version: Comput. Phys. Comm. 181 (2010) 703Does the new version supersede the previous version?: YesNature of problem: Solve geodesic equation, parallel and Fermi-Walker transport in four-dimensional Lorentzian spacetimes. Determine gravitational lensing by integration of Jacobi equation and parallel transport of Sachs basis.Solution method: Integration of ordinary differential equations.Reasons for new version: The main novelty of the current version is the extension to integrate the Jacobi equation and the parallel transport of the Sachs basis along null geodesics. In combination, the change of the cross section of a light bundle and thus the gravitational lensing effect of a spacetime can be determined. Furthermore, we have implemented several new metrics.Summary of revisions: The main novelty of the current version is the integration of the Jacobi equation and the parallel transport of the Sachs basis along null geodesics. The corresponding set of equations readd2xμdλ2=-Γρ

  1. Phosphodiesterase 4D gene polymorphisms in sudden sensorineural hearing loss.

    PubMed

    Chien, Chen-Yu; Tai, Shu-Yu; Wang, Ling-Feng; Hsi, Edward; Chang, Ning-Chia; Wang, Hsun-Mo; Wu, Ming-Tsang; Ho, Kuen-Yao

    2016-09-01

    The phosphodiesterase 4D (PDE4D) gene has been reported as a risk gene for ischemic stroke. The vascular factors are between the hypothesized etiologies of sudden sensorineural hearing loss (SSNHL), and this genetic effect might be attributed for its role in SSNHL. We hypothesized that genetic variants of the PDE4D gene are associated with susceptibility to SSNHL. We conducted a case-control study with 362 SSNHL cases and 209 controls. Three single nucleotide polymorphisms (SNPs) were selected. The genotypes were determined using TaqMan technology. Hardy-Weinberg equilibrium (HWE) was tested for each SNP, and genetic effects were evaluated according to three inheritance modes. We carried out sex-specific analysis to analyze the overall data. All three SNPs were in HWE. When subjects were stratified by sex, the genetic effect was only evident in females but not in males. The TT genotype of rs702553 exhibited an adjusted odds ratio (OR) of 3.83 (95 % confidence interval = 1.46-11.18) (p = 0.006) in female SSNHL. The TT genotype of SNP rs702553 was associated with female SSNHL under the recessive model (p = 0.004, OR 3.70). In multivariate logistic regression analysis, TT genotype of rs702553 was significantly associated with female SSNHL (p = 0.0043, OR 3.70). These results suggest that PDE4D gene polymorphisms influence the susceptibility for the development of SSNHL in the southern Taiwanese female population.

  2. ICT4D: A Computer Science Perspective

    NASA Astrophysics Data System (ADS)

    Sutinen, Erkki; Tedre, Matti

    The term ICT4D refers to the opportunities of Information and Communication Technology (ICT) as an agent of development. Research in that field is often focused on evaluating the feasibility of existing technologies, mostly of Western or Far East Asian origin, in the context of developing regions. A computer science perspective is complementary to that agenda. The computer science perspective focuses on exploring the resources, or inputs, of a particular context and on basing the design of a technical intervention on the available resources, so that the output makes a difference in the development context. The modus operandi of computer science, construction, interacts with evaluation and exploration practices. An analysis of a contextualized information technology curriculum of Tumaini University in southern Tanzania shows the potential of the computer science perspective for designing meaningful information and communication technology for a developing region.

  3. Soft Route to 4D Tomography

    NASA Astrophysics Data System (ADS)

    Taillandier-Thomas, Thibault; Roux, Stéphane; Hild, François

    2016-07-01

    Based on the assumption that the time evolution of a sample observed by computed tomography requires many less parameters than the definition of the microstructure itself, it is proposed to reconstruct these changes based on the initial state (using computed tomography) and very few radiographs acquired at fixed intervals of time. This Letter presents a proof of concept that for a fatigue cracked sample its kinematics can be tracked from no more than two radiographs in situations where a complete 3D view would require several hundreds of radiographs. This 2 order of magnitude gain opens the way to a "computed" 4D tomography, which complements the recent progress achieved in fast or ultrafast computed tomography, which is based on beam brightness, detector sensitivity, and signal acquisition technologies.

  4. The digit ratio (2D:4D) in China: A meta-analysis.

    PubMed

    Xu, Yin; Zheng, Yong

    2015-01-01

    To explore the 2D:4D in China (mainland and Taiwan) and to analyze the influences of ethnicity, digit measurement methods, age, and latitude on Chinese 2D:4D. We here conducted a meta-analysis of the results of 28 studies. A total of 112 independent samples and 19,093 participants were included. The sex difference in left 2D:4D only approached significance when outliers were removed (P = 0.078), whereas the right 2D:4D was significantly lower in males compared to females, showing that the magnitude of sex difference was greater for the right hand than for the left hand. No significant differences were found in the 2D:4D between Han and ethnic minorities. The 2D:4D of samples measured using indirect digit measurement tended to be lower than in samples measured using direct digit measurement. Moreover, there were no effects of age and latitude on the 2D:4D in China. We concluded that the sex differences in Chinese 2D:4D are consistent with the results from western studies, and that genetic pool differences rather than latitude-related environmental variables affect the 2D:4D in China. In addition, 2D:4D measurements obtained by different digit measurement techniques should not be combined within one study, or used together in comparative studies. © 2014 Wiley Periodicals, Inc.

  5. The Relationship Between Digit Ratio (2D:4D) and Sexual Orientation in Men from China.

    PubMed

    Xu, Yin; Zheng, Yong

    2016-04-01

    We examined the relationship between 2D:4D digit ratio and sexual orientation in men from China and analyzed the influences of the components used to assess sexual orientation and the criteria used to classify individuals as homosexual on this relationship. A total of 309 male and 110 female participants took part in a web-based survey. Our results showed that heterosexual men had a significantly lower 2D:4D than heterosexual women and exclusively homosexual men had a significantly higher left 2D:4D than heterosexual men whereas only exclusively homosexual men had a significantly higher right 2D:4D than heterosexual men when sexual orientation was assessed via sexual attraction. The left 2D:4D showed a significant positive correlation with sexual identity, sexual attraction, and sexual behavior, and the right 2D:4D showed a significant positive correlation with sexual attraction. The effect sizes for differences in 2D:4D between homosexual and heterosexual men varied according to criteria used to classify individuals as homosexual and sexual orientation components; the more stringent the criteria (scores closer to the homosexual category), the larger the effect sizes; further, sexual attraction yielded the largest effect size. There were no significant effects of age and latitude on Chinese 2D:4D. This study contributes to the current understanding of the relationship between 2D:4D and male sexual orientation.

  6. The role of semaphorin 4D in tumor development and angiogenesis in human breast cancer

    PubMed Central

    Jiang, Hongchao; Chen, Ceshi; Sun, Qiangming; Wu, Jing; Qiu, Lijuan; Gao, Change; Liu, Weiqing; Yang, Jun; Jun, Nie; Dong, Jian

    2016-01-01

    Background Semaphorin 4D (Sema4D) is highly expressed in certain types of tumors and functions in the regulation of tumor angiogenesis and growth. However, it is still not clear regarding the roles of Sema4D in breast cancer. This study was designed to explore the effects of Sema4D on proliferation, cell cycle progression, apoptosis, invasion, migration, tumor growth, and angiogenesis in breast cancer. Materials and methods The expression level of Sema4D was investigated in MCF10A, 184A1, HCC1937, MDA-MB-468, MDA-MB-231, Hs578T, BT474, MCF-7, and T47D breast cancer cell lines by Western blotting analysis. Sema4D downregulation or overexpression was established by infection with lentiviruses-encoding Sema4D short hairpin RNA (shRNA) or Sema4D. To evaluate the effects of Sema4D on cell proliferation, cell cycle progression, apoptosis, invasion, and migration of MDA-MB-231 and MDA-MB-468 cells, methods including MTT assay, flow cytometry, wound healing assay, and transwell experiments were applied. BALB/c nude mice were injected with MDA-MB-231 cells, which were respectively infected with lentiviruses-encoding Sema4D, Sema4D shRNA, and GFP, followed by tumor angiogenesis assay. Results Sema4D was expressed at higher levels in breast cancer cell lines compared with the normal human breast epithelial cell lines, especially in MDA-MB-231 and MDA-MB-468 cells. Cell proliferation ability was remarkably inhibited in Sema4D downregulated condition, whereas the proportions of cells in the G0/G1 phase and apoptosis increased in MDA-MB-231 and MDA-MB-468 cells. In addition, the invasion and migration abilities of these cells were obviously reduced. Xenograft growth as well as angiogenesis was inhibited when infected with lentiviruses-encoding Sema4D shRNA in vivo. Conclusion Downregulation of Sema4D had notable influence on cell proliferation ability, invasion, migration, and apoptosis of both MDA-MB-231 and MDA-MB-468 cells. Furthermore, infection with lentiviruses

  7. Finger length ratio (2D:4D) in left- and right-handed males.

    PubMed

    Stoyanov, Zlatislav; Marinov, Miroslav; Pashalieva, Irina

    2009-01-01

    The finger length ratio (2D:4D) is a biomarker for the prenatal levels of testosterone. The prenatal effects of testosterone on the development of brain hemispheres are considered as a key factor in the etiology of left-handedness. We tested whether 2D:4D correlates with the type of handedness in males (18 right-handers and 18 left-handers). Right hand 2D:4D, left hand 2D:4D, average 2D:4D, and the difference between right and left 2D:4D (D(r-l)) were compared. The value of D(r-l) in left-handers was significantly lower than D(r-l) in right-handers. This result can be interpreted as proof that left-handers were subjected to higher levels of testosterone in utero.

  8. Opening the Black Box of ICT4D: Advancing Our Understanding of ICT4D Partnerships

    ERIC Educational Resources Information Center

    Park, Sung Jin

    2013-01-01

    The term, Information and Communication Technologies for Development (ICT4D), pertains to programs or projects that strategically use ICTs (e.g. mobile phones, computers, and the internet) as a means toward the socio-economic betterment for the poor in developing contexts. Gaining the political and financial support of the international community…

  9. Opening the Black Box of ICT4D: Advancing Our Understanding of ICT4D Partnerships

    ERIC Educational Resources Information Center

    Park, Sung Jin

    2013-01-01

    The term, Information and Communication Technologies for Development (ICT4D), pertains to programs or projects that strategically use ICTs (e.g. mobile phones, computers, and the internet) as a means toward the socio-economic betterment for the poor in developing contexts. Gaining the political and financial support of the international community…

  10. Effects of diversity and coupling on transport properties of globally coupled active Brownian particles

    NASA Astrophysics Data System (ADS)

    Wu, Dan; Zhu, Shiqun

    2013-03-01

    Based on recent work [B. Lindner and E. M., Nicola, Phys. Rev. Lett. 101 (2008) 190603], the transport of N globally coupled Brownian motors with diversity is investigated. By applying the mean-field approximation, the effects of the diversity disturbance and the coupling strength on the transport of the coupled system are discussed both theoretically and numerically. It is found that the diversity reduces the diffusion dramatically for small bias and increases the diffusion gradually for large bias. The collective motion shows a resonant dependence on the coupling strength in a region of small bias.

  11. Entropy of 4D extremal black holes

    NASA Astrophysics Data System (ADS)

    Johnson, Clifford V.; Khuri, Ramzi R.; Myers, Robert C.

    1996-02-01

    We derive the Bekenstein-Hawking entropy formula for four-dimensional Reissner-Nordström extremal black holes in type II string theory. The derivation is performed in two separate (T-dual) weak coupling pictures. One uses a type IIB bound state problem of D5- and D1-branes, while the other uses a bound state problem of D0- and D4-branes with macroscopic fundamental type IIA strings. In both cases, the D-brane systems are also bound to a Kaluza-Klein monopole, which then yields the four-dimensional black hole at strong coupling.

  12. The effect of coupling line loss in microstrip to dielectric resonator coupling

    NASA Technical Reports Server (NTRS)

    Hearn, C. P.; Bradshaw, E. S.; Trew, R. J.

    1990-01-01

    The interaction between a dielectric resonator and a microstrip transmission line is fundamentally a field phenomenon. However, the model of Figure 1b widely is used to represent the arrangement in Figure 1a, and predicts the behavior encountered in practice. The microstrip line of length l = n(lambda)/4 between the input and coupling planes and the lambda/4 open-circuit stub usually is assumed to be lossless. This paper considers the effect of coupling line loss on the unloaded-Q and coupling coefficient beta of the combination. It shows that transmission line loss can cause the decrease in unloaded-Q that has been observed to occur with tight coupling, and limits the coupling coefficient to a much lower value than would be obtained with a lossless coupling line.

  13. Chaos in a 4D dissipative nonlinear fermionic model

    NASA Astrophysics Data System (ADS)

    Aydogmus, Fatma

    2015-12-01

    Gursey Model is the only possible 4D conformally invariant pure fermionic model with a nonlinear self-coupled spinor term. It has been assumed to be similar to the Heisenberg's nonlinear generalization of Dirac's equation, as a possible basis for a unitary description of elementary particles. Gursey Model admits particle-like solutions for the derived classical field equations and these solutions are instantonic in character. In this paper, the dynamical nature of damped and forced Gursey Nonlinear Differential Equations System (GNDES) are studied in order to get more information on spinor type instantons. Bifurcation and chaos in the system are observed by constructing the bifurcation diagrams and Poincaré sections. Lyapunov exponent and power spectrum graphs of GNDES are also constructed to characterize the chaotic behavior.

  14. Second to fourth digit ratio (2D:4D) and testosterone in men.

    PubMed

    Manning, J T; Wood, S; Vang, E; Walton, J; Bundred, P E; van Heyningen, C; Lewis-Jones, D I

    2004-09-01

    To investigate the relationship between 2D:4D and testosterone in men attending an infertility clinic and men drawn from the general population. Data on 2D:4D and testosterone from two samples were collected: (1) 43 men attending an infertility clinic, and (2) 51 men drawn from the general population without regard to fertility. In sample (1) there were negative associations between 2D:4D and testicular function, and men with lower 2D:4D in their right compared to left hand had higher testosterone levels than men with higher 2D:4D in their right compared to left hand. Sample (2) showed no significant associations between 2D:4D or side differences in 2D:4D and testosterone. Adult levels of testosterone may be related to aspects of 2D:4D in samples which contain men with compromised testicular function, but not in men from normative samples. Associations between 2D:4D and fertility-associated traits probably arise from early organisational effects of testosterone rather than from activational effects of current testosterone.

  15. Orbital-selective singlet dimer formation and suppression of double exchange in 4d and 5d systems

    NASA Astrophysics Data System (ADS)

    Streltsov, Sergey; Cao, Gang; Khomskii, Daniel

    One of the main mechanisms of ferromagnetic ordering in conducting materials is the double exchange (DE). It is usually supposed in DE model that the Hund's coupling JH is much larger than electron hopping t; in this case one stabilizes the state with maximum spin per pair of ions, which finally leads to ferromagnetism in bulk systems. We show that in the dimerized 4 d / 5 d transition metal oxides for which JH is reduced and t is in contrast enhanced, another situation is possible, when formation of the spin-singlets on delocalized orbitals is more favorable. This leads to suppression of the DE and to a strong decrease of the total spin. The model calculations using the dynamical mean-field theory show that this effect survives even in the extended systems, not only for dimers. Such a situation is realized, e.g., in Y5Mo2O12, CrO2 under pressure and in many other 4 d / 5 d based materials. Another mechanism, which may suppress DE and which is also typical for 4 d / 5 d compounds is the spin-orbit coupling (SOC). We show on the example of Ba5AlIr2O11, that in this system it is the combination of molecular-orbital formation and SOC that strongly decreases magnetic moment on Ir. Civil Research and Development Foundation via FSCX-14-61025-0.

  16. Spatiotemporal directional analysis of 4D echocardiography

    NASA Astrophysics Data System (ADS)

    Angelini-Casadevall, Elsa D.; Laine, Andrew F.; Takuma, Shin; Homma, Shunichi

    2000-12-01

    Speckle noise corrupts ultrasonic data by introducing sharp changes in an echocardiographic image intensity profile, while attenuation alters the intensity of equally significant cardiac structures. These properties introduce inhomogeneity in the spatial domain and suggests that measures based on phase information rather than intensity are more appropriate for denoising and cardiac border detection. The present analysis method relies on the expansion of temporal ultrasonic volume data on complex exponential wavelet-like basis functions called Brushlets. These basis functions decompose a signal into distinct patterns of oriented textures. Projected coefficients are associated with distinct 'brush strokes' of a particular size and orientation. 4D overcomplete brushlet analysis is applied to temporal echocardiographic values. We show that adding the time dimension in the analysis dramatically improves the quality and robustness of the method without adding complexity in the design of a segmentation tool. We have investigated mathematical and empirical methods for identifying the most 'efficient' brush stroke sizes and orientations for decomposition and reconstruction on both phantom and clinical data. In order to determine the 'best tiling' or equivalently, the 'best brushlet basis', we use an entorpy-based information cost metric function. Quantitative validation and clinical applications of this new spatio-temporal analysis tool are reported for balloon phantoms and clinical data sets.

  17. Quantum dissipative effect of one dimension coupled anharmonic oscillator

    SciTech Connect

    Sulaiman, A.; Zen, Freddy P.

    2015-04-16

    Quantum dissipative effect of one dimension coupled anharmonic oscillator is investigated. The systems are two coupled harmonic oscillator with the different masses. The dissipative effect is studied based on the quantum state diffusion formalism. The result show that the anharmonic effect increase the amplitude but the lifetime of the oscillation depend on the damping coefficient and do not depend on the temperature.

  18. Familial digit ratio (2D:4D) associations in a general population sample from Wales.

    PubMed

    Richards, Gareth; Bellin, Wynford; Davies, William

    2017-09-01

    The relative length of the second and fourth fingers (2D:4D) may be a sex-linked correlate of prenatal androgen exposure. However, the nature of the sex-linkage is controversial, with evidence for both X- and Y-linkage of the 2D:4D phenotype. To examine transgenerational effects relating to sex-linkage. In addition, assortative mating on 2D:4D was considered, as well as associations between 2D:4D and age and sex. A family study was conducted. Parents and offspring completed a demographic questionnaire, and digit ratios were calculated from photocopies of participants' hands. We recruited and phenotyped 585 individuals attending a cultural festival in Wales. 2D:4D information was available for 47 mother-son dyads, 70 mother-daughter dyads, 31 father-son dyads and 30 father-daughter dyads. Correlations between 2D:4D of parents and children, as well as between mothers and fathers were conducted. 2D:4D was also examined in relation to age and sex. There was a sex difference in 2D:4D (males4D, but no significant correlation between mother and son ratios, nor between father and offspring ratios. The overall pattern of correlations (with emphasis on father-son dyads) was not supportive of Y-linkage. There was a positive correlation between 2D:4D and age in children, and a negative correlation between 2D:4D and age in adults, and no evidence of assortative mating. Our data are consistent with the notion of 2D:4D as a sexually-dimorphic, mildly age-sensitive, and transgenerationally-transmitted trait that is more likely to be X- than Y-linked. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  19. Simultaneous motion estimation and image reconstruction (SMEIR) for 4D cone-beam CT

    SciTech Connect

    Wang, Jing; Gu, Xuejun

    2013-10-15

    Purpose: Image reconstruction and motion model estimation in four-dimensional cone-beam CT (4D-CBCT) are conventionally handled as two sequential steps. Due to the limited number of projections at each phase, the image quality of 4D-CBCT is degraded by view aliasing artifacts, and the accuracy of subsequent motion modeling is decreased by the inferior 4D-CBCT. The objective of this work is to enhance both the image quality of 4D-CBCT and the accuracy of motion model estimation with a novel strategy enabling simultaneous motion estimation and image reconstruction (SMEIR).Methods: The proposed SMEIR algorithm consists of two alternating steps: (1) model-based iterative image reconstruction to obtain a motion-compensated primary CBCT (m-pCBCT) and (2) motion model estimation to obtain an optimal set of deformation vector fields (DVFs) between the m-pCBCT and other 4D-CBCT phases. The motion-compensated image reconstruction is based on the simultaneous algebraic reconstruction technique (SART) coupled with total variation minimization. During the forward- and backprojection of SART, measured projections from an entire set of 4D-CBCT are used for reconstruction of the m-pCBCT by utilizing the updated DVF. The DVF is estimated by matching the forward projection of the deformed m-pCBCT and measured projections of other phases of 4D-CBCT. The performance of the SMEIR algorithm is quantitatively evaluated on a 4D NCAT phantom. The quality of reconstructed 4D images and the accuracy of tumor motion trajectory are assessed by comparing with those resulting from conventional sequential 4D-CBCT reconstructions (FDK and total variation minimization) and motion estimation (demons algorithm). The performance of the SMEIR algorithm is further evaluated by reconstructing a lung cancer patient 4D-CBCT.Results: Image quality of 4D-CBCT is greatly improved by the SMEIR algorithm in both phantom and patient studies. When all projections are used to reconstruct a 3D-CBCT by FDK, motion

  20. Ultrafast Elemental and Oxidation-State Mapping of Hematite by 4D Electron Microscopy.

    PubMed

    Su, Zixue; Baskin, J Spencer; Zhou, Wuzong; Thomas, John M; Zewail, Ahmed H

    2017-04-05

    We describe a new methodology that sheds light on the fundamental electronic processes that occur at the subsurface regions of inorganic solid photocatalysts. Three distinct kinds of microscopic imaging are used that yield spatial, temporal, and energy-resolved information. We also carefully consider the effect of photon-induced near-field electron microscopy (PINEM), first reported by Zewail et al. in 2009. The value of this methodology is illustrated by studying afresh a popular and viable photocatalyst, hematite, α-Fe2O3 that exhibits most of the properties required in a practical application. By employing high-energy electron-loss signals (of several hundred eV), coupled to femtosecond temporal resolution as well as ultrafast energy-filtered transmission electron microscopy in 4D, we have, inter alia, identified Fe(4+) ions that have a lifetime of a few picoseconds, as well as associated photoinduced electronic transitions and charge transfer processes.

  1. Meson thermalization by baryon injection in D4/D6 model

    NASA Astrophysics Data System (ADS)

    Rezaei, Z.

    2016-12-01

    We study meson thermalization in a strongly coupled plasma of quarks and gluons using AdS/CFT duality technique. Four dimensional large-Nc QCD is considered as a theory governing this quark-gluon plasma (QGP) and D4/D6-brane model is chosen to be its holographic dual theory. In order to investigate meson thermalization, we consider a time-dependent change of baryon number chemical potential. Thermalization in gauge theory side corresponds to horizon formation on the probe flavor brane in the gravity side. The gravitational dual theory is compactified on a circle that the inverse of its radius is proportional to energy scale of dual gauge theory. It is seen that increase of this energy scale results in thermalization time dilation. In addition we study the effect of magnetic field on meson thermalization. It will be seen that magnetic field also prolongs thermalization process by making mesons more stable.

  2. Computer simulation of the coupling slots effects for on-axis coupled accelerating structures.

    NASA Astrophysics Data System (ADS)

    Salakhoutdinov, A. F.; Shvedunov, V. I.

    1997-05-01

    The presence of coupling elements in accelerating structures leads to the violation of axial symmetry of accelerating field and it may cause displacement, defocusing and non-linear distortion of phase space. As a result the growth of transverse emittance occures. From the other hand, these effects may be used for designing of RF- focusing accelerating structure for electron accelerators of various types. The numerical simulation of electrodynamical properties of on-axis coupled accelerating structure taking into account the coupling slots have been made. The characteristics of fields excited within the coupling cell have been investigated. The numerical estimations of various multipolarity components of transverse forces acting upon a particle inside the coupling cell have been achieved.

  3. Examination marks of male university students positively correlate with finger length ratios (2D:4D).

    PubMed

    Romano, Maria; Leoni, Barbara; Saino, Nicola

    2006-02-01

    Intersexual and intrasexual variation in second to fourth digit length (2D:4D) in humans may result from differential exposure to fetal testosterone. 2D:4D predicts several physiological, psychological and performance traits in adulthood. These relationships may reflect the 'pleiotropic' effects of testosterone on development of digits and diverse organ systems, which are expressed in adulthood. We hypothesized that 2D:4D also predicts academic success of students. 2D:4D of right hand positively predicted examination marks of males from two three-year degree courses (TYDCs). Marks of females did not covary with 2D:4D. Males from the two TYDCs differed in 2D:4D. The present results thus add to the rapidly accumulating literature on 2D:4D showing correlations with phenotypic traits in humans. If testosterone affects 2D:4D and intellectual performance, our results suggest that testosterone levels are under stabilizing selection because of effects on performance traits documented in previous studies and antagonistic effects on intellectual performance (present study).

  4. 17 CFR 260.4d-8 - Content.

    Code of Federal Regulations, 2010 CFR

    2005-04-01

    ... 17 Commodity and Securities Exchanges 3 2005-04-01 2005-04-01 false Content. 260.4d-8 Section 260.4d-8 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION (CONTINUED) GENERAL RULES AND REGULATIONS, TRUST INDENTURE ACT OF 1939 Rules Under Section 304 § 260.4d-8 Content. (a)...

  5. 17 CFR 260.4d-8 - Content.

    Code of Federal Regulations, 2010 CFR

    2012-04-01

    ... 17 Commodity and Securities Exchanges 3 2012-04-01 2012-04-01 false Content. 260.4d-8 Section 260.4d-8 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION (CONTINUED) GENERAL RULES AND REGULATIONS, TRUST INDENTURE ACT OF 1939 Rules Under Section 304 § 260.4d-8 Content. (a)...

  6. 17 CFR 260.4d-8 - Content.

    Code of Federal Regulations, 2010 CFR

    2011-04-01

    ... 17 Commodity and Securities Exchanges 3 2011-04-01 2011-04-01 false Content. 260.4d-8 Section 260.4d-8 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION (CONTINUED) GENERAL RULES AND REGULATIONS, TRUST INDENTURE ACT OF 1939 Rules Under Section 304 § 260.4d-8 Content. (a)...

  7. 17 CFR 260.4d-8 - Content.

    Code of Federal Regulations, 2010 CFR

    2000-04-01

    ... 17 Commodity and Securities Exchanges 3 2000-04-01 2000-04-01 false Content. 260.4d-8 Section 260.4d-8 Commodity and Securities Exchanges GENERAL RULES AND REGULATIONS, TRUST INDENTURE ACT OF 1939 Rules Under Section 304 § 260.4d-8 Content. (a) Each application for an order under section 304(d)...

  8. Loop-corrected Virasoro symmetry of 4D quantum gravity

    NASA Astrophysics Data System (ADS)

    He, T.; Kapec, D.; Raclariu, A.; Strominger, A.

    2017-08-01

    Recently a boundary energy-momentum tensor T zz has been constructed from the soft graviton operator for any 4D quantum theory of gravity in asymptotically flat space. Up to an "anomaly" which is one-loop exact, T zz generates a Virasoro action on the 2D celestial sphere at null infinity. Here we show by explicit construction that the effects of the IR divergent part of the anomaly can be eliminated by a one-loop renormalization that shifts T zz .

  9. Heritability of digit ratio (2D:4D) in rhesus macaques (Macaca mulatta).

    PubMed

    Nelson, Emma; Voracek, Martin

    2010-01-01

    The second-to-fourth digit ratio (2D:4D) is a putative biomarker for prenatal androgen effects, which has been widely employed to study androgenic-programming effects on shaping sex-linked traits and behaviours in humans. This approach is now increasingly applied to non-human species. Heritability studies of 2D:4D in both humans and zebra finches indicate substantial genetic contributions to the expression of this trait. This study examines the heritability of 2D:4D in rhesus macaques, based on the resemblance of mother-infant dyads, to see how these compare with human values. Results suggest that familial resemblance in 2D:4D is also strong in rhesus monkeys. Heritability estimates were within the range of estimates from human studies. These preliminary results suggest that the strength of heritability of 2D:4D may generalize across taxa.

  10. [Dechlorination degradation of 2,4-D by nanoscale Fe3O4].

    PubMed

    Fang, Guo-Dong; Si, You-Bin

    2010-06-01

    Reductive transformation of 2,4-Dichlorophenoxyacetic acid (2,4-D) by nanoscale Fe3O4 was studied, and the effects of 2,4-D initial concentration, the dosage of nanoscale Fe3O4, pH and temperature on degradation rate of 2,4-D were investigated. The results showed that 48% 2,4-D with initial concentration of 10 mg/L was transformed within 48 h in the presence of 300 mg/L nanoscale Fe3O4. The degradation of 2,4-D was a reductive dechlorination process, and the concentration of chloride ion increased sharply with the degration of the 2,4-D. Disappearance of parent species and formation of reaction intermediates and products were analyzed by LC/MS. The transformation of 2,4-D followed a primary pathway of its complete reduction to phenol and a secondary pathway of sequential reductive hydrogenolysis to 2,4-dichlorophenol (2,4-DCP), 4-chlorophenol (4-CP) or 2-chlorophenol (2-CP) and phenol. The degradation equations of 2,4-D by nanoscale Fe3O4 conformed to pseudo-first-order kinetics, and the reaction rate constant (K) of 4-CP, 2,4-DCP and phenol were 0.0043 h(-1), 0.0026 h(-1) and 0.0032 h(-1), respectively. The degradation rate increased with an increase in initial concentration of 2,4-D from 0 mg/L to 10 mg/L, and increasing the dosage of nanoscale Fe3O4 from 0 mg/L to 300 mg/L. The pH of reaction solution significantly influenced reductive degradation of 2,4-D, and the optimum pH value was 3.0. Besides, high temperature could improve dechlorination rate of 2,4-D.

  11. Recurrent selection with reduced 2,4-D amine doses results in the rapid evolution of 2,4-D herbicide resistance in wild radish (Raphanus raphanistrum L.).

    PubMed

    Ashworth, Michael B; Walsh, Michael J; Flower, Ken C; Powles, Stephen B

    2016-11-01

    When used at effective doses, weed resistance to auxinic herbicides has been slow to evolve when compared with other modes of action. Here we report the evolutionary response of a herbicide-susceptible population of wild radish (Raphanus raphanistrum L.) and confirm that sublethal doses of 2,4-dichlorophenoxyacetic acid (2,4-D) amine can lead to the rapid evolution of 2,4-D resistance and cross-resistance to acetolactate synthase (ALS)-inhibiting herbicides. Following four generations of 2,4-D selection, the progeny of a herbicide-susceptible wild radish population evolved 2,4-D resistance, increasing the LD50 from 16 to 138 g ha(-1) . Along with 2,4-D resistance, cross-resistance to the ALS-inhibiting herbicides metosulam (4.0-fold) and chlorsulfuron (4.5-fold) was evident. Pretreatment of the 2,4-D-selected population with the cytochrome P450 inhibitor malathion restored chlorsulfuron to full efficacy, indicating that cross-resistance to chlorsulfuron was likely due to P450-catalysed enhanced rates of herbicide metabolism. This study is the first to confirm the rapid evolution of auxinic herbicide resistance through the use of low doses of 2,4-D and serves as a reminder that 2,4-D must always be used at highly effective doses. With the introduction of transgenic auxinic-herbicide-resistant crops in the Americas, there will be a marked increase in auxinic herbicide use and therefore the risk of resistance evolution. Auxinic herbicides should be used only at effective doses and with diversity if resistance is to remain a minimal issue. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  12. Spin-orbit coupled potential energy surfaces and properties using effective relativistic coupling by asymptotic representation

    NASA Astrophysics Data System (ADS)

    Ndome, Hameth; Eisfeld, Wolfgang

    2012-08-01

    A new method has been reported recently [H. Ndome, R. Welsch, and W. Eisfeld, J. Chem. Phys. 136, 034103 (2012)], 10.1063/1.3675846 that allows the efficient generation of fully coupled potential energy surfaces (PESs) including derivative and spin-orbit (SO) coupling. The method is based on the diabatic asymptotic representation of the molecular fine structure states and an effective relativistic coupling operator and therefore is called effective relativistic coupling by asymptotic representation (ERCAR). The resulting diabatic spin-orbit coupling matrix is constant and the geometry dependence of the coupling between the eigenstates is accounted for by the diabatization. This approach allows to generate an analytical model for the fully coupled PESs without performing any ab initio SO calculations (except perhaps for the atoms) and thus is very efficient. In the present work, we study the performance of this new method for the example of hydrogen iodide as a well-established test case. Details of the diabatization and the accuracy of the results are investigated in comparison to reference ab initio calculations. The energies of the adiabatic fine structure states are reproduced in excellent agreement with reference ab initio data. It is shown that the accuracy of the ERCAR approach mainly depends on the quality of the underlying ab initio data. This is also the case for dissociation and vibrational level energies, which are influenced by the SO coupling. A method is presented how one-electron operators and the corresponding properties can be evaluated in the framework of the ERCAR approach. This allows the computation of dipole and transition moments of the fine structure states in good agreement with ab initio data. The new method is shown to be very promising for the construction of fully coupled PESs for more complex polyatomic systems to be used in quantum dynamics studies.

  13. TU-C-BRD-01: Image Guided SBRT I: Multi-Modality 4D Imaging

    SciTech Connect

    Cai, J; Mageras, G; Pan, T

    2014-06-15

    Motion management is one of the critical technical challenges for radiation therapy. 4D imaging has been rapidly adopted as essential tool to assess organ motion associated with respiratory breathing. A variety of 4D imaging techniques have been developed and are currently under development based on different imaging modalities such as CT, MRI, PET, and CBCT. Each modality provides specific and complementary information about organ and tumor respiratory motion. Effective use of each different technique or combined use of different techniques can introduce a comprehensive management of tumor motion. Specifically, these techniques have afforded tremendous opportunities to better define and delineate tumor volumes, more accurately perform patient positioning, and effectively apply highly conformal therapy techniques such as IMRT and SBRT. Successful implementation requires good understanding of not only each technique, including unique features, limitations, artifacts, imaging acquisition and process, but also how to systematically apply the information obtained from different imaging modalities using proper tools such as deformable image registration. Furthermore, it is important to understand the differences in the effects of breathing variation between different imaging modalities. A comprehensive motion management strategy using multi-modality 4D imaging has shown promise in improving patient care, but at the same time faces significant challenges. This session will focuses on the current status and advances in imaging respiration-induced organ motion with different imaging modalities: 4D-CT, 4D-MRI, 4D-PET, and 4D-CBCT/DTS. Learning Objectives: Understand the need and role of multimodality 4D imaging in radiation therapy. Understand the underlying physics behind each 4D imaging technique. Recognize the advantages and limitations of each 4D imaging technique.

  14. A 4D-optimization concept for scanned ion beam therapy.

    PubMed

    Graeff, Christian; Lüchtenborg, Robert; Eley, John Gordon; Durante, Marco; Bert, Christoph

    2013-12-01

    Scanned carbon beam therapy offers advantageous dose distributions and an increased biological effect. Treating moving targets is complex due to sensitivity to range changes and interplay. We propose a 4D treatment planning concept that considers motion during particle number optimization. The target was subdivided into sectors, one for each motion phase of a 4D-CT. Each sector was non-rigidly transformed to its motion phase and there targeted by a dedicated raster field (RST). Therefore, the resulting 4D-RST compensated target motion and range changes. A 4D treatment control system (TCS) was needed for synchronized delivery to the measured patient motion. 4D-optimized plans were simulated for 9 NSCLC lung cancer patients and compared to static irradiation at end-exhale. A prototype TCS was implemented and successfully tested in a film experiment. The 4D-optimized treatment plan resulted in only slightly lower dose coverage of the target compared to static optimization, with V 95% of 97.9% (median, range 96.5-99.4%) vs. 99.3% (98.5-99.8%), with negligible overdose. The conformity number was comparable at 88.2% (85.1-92.5%) vs. 85.2% (79.9-91.2%) for 4D and static, respectively. We implemented and tested a 4D treatment plan optimization method resulting in highly conformal dose delivery. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  15. Digit Ratio (2D:4D) and Handgrip Strength in Hani Ethnicity

    PubMed Central

    Zhao, Dapeng; Yu, Keli; Zhang, Xinghua; Zheng, Lianbin

    2013-01-01

    Introduction The ratio of the length of the second finger to the fourth finger (2D:4D) in humans is considered as a putative marker of prenatal exposure to testosterone, and has been progressively adopted as one useful tool to evaluate the effect of prenatal hormones in some traits such as physical ability. Handgrip strength is one authentic measure of physical ability and is generally used on the anthropological research within an evolutionary viewpoint. Methods Here we present the first evidence on 2D:4D and handgrip strength on adult participants of Hani ethnicity and explore the relationship between digit ratio (2D:4D) and handgrip strength. We examined 2D:4D and handgrip strength of 80 males and 60 females at Bubeng village, in the Yunnan province of China. Results The mean 2D:4D in females was higher than that in males for each hand. Females showed significantly higher 2D:4D than males in the right hand rather than in the left hand. Males displayed significantly higher handgrip strength than females for both hands. Handgrip strength decreased with age for both sexes. A significant negative correlation between 2D:4D and handgrip strength was found in the right hand of males. Conclusion The relationship between 2D:4D and handgrip strength may be attributed to evolutionary drive of sexual selection operating on fetal programming. PMID:24205044

  16. Digit ratio (2D:4D) and handgrip strength in Hani ethnicity.

    PubMed

    Zhao, Dapeng; Yu, Keli; Zhang, Xinghua; Zheng, Lianbin

    2013-01-01

    The ratio of the length of the second finger to the fourth finger (2D:4D) in humans is considered as a putative marker of prenatal exposure to testosterone, and has been progressively adopted as one useful tool to evaluate the effect of prenatal hormones in some traits such as physical ability. Handgrip strength is one authentic measure of physical ability and is generally used on the anthropological research within an evolutionary viewpoint. Here we present the first evidence on 2D:4D and handgrip strength on adult participants of Hani ethnicity and explore the relationship between digit ratio (2D:4D) and handgrip strength. We examined 2D:4D and handgrip strength of 80 males and 60 females at Bubeng village, in the Yunnan province of China. The mean 2D:4D in females was higher than that in males for each hand. Females showed significantly higher 2D:4D than males in the right hand rather than in the left hand. Males displayed significantly higher handgrip strength than females for both hands. Handgrip strength decreased with age for both sexes. A significant negative correlation between 2D:4D and handgrip strength was found in the right hand of males. The relationship between 2D:4D and handgrip strength may be attributed to evolutionary drive of sexual selection operating on fetal programming.

  17. Actively triggered 4d cone-beam CT acquisition

    SciTech Connect

    Fast, Martin F.; Wisotzky, Eric; Oelfke, Uwe; Nill, Simeon

    2013-09-15

    Purpose: 4d cone-beam computed tomography (CBCT) scans are usually reconstructed by extracting the motion information from the 2d projections or an external surrogate signal, and binning the individual projections into multiple respiratory phases. In this “after-the-fact” binning approach, however, projections are unevenly distributed over respiratory phases resulting in inefficient utilization of imaging dose. To avoid excess dose in certain respiratory phases, and poor image quality due to a lack of projections in others, the authors have developed a novel 4d CBCT acquisition framework which actively triggers 2d projections based on the forward-predicted position of the tumor.Methods: The forward-prediction of the tumor position was independently established using either (i) an electromagnetic (EM) tracking system based on implanted EM-transponders which act as a surrogate for the tumor position, or (ii) an external motion sensor measuring the chest-wall displacement and correlating this external motion to the phase-shifted diaphragm motion derived from the acquired images. In order to avoid EM-induced artifacts in the imaging detector, the authors devised a simple but effective “Faraday” shielding cage. The authors demonstrated the feasibility of their acquisition strategy by scanning an anthropomorphic lung phantom moving on 1d or 2d sinusoidal trajectories.Results: With both tumor position devices, the authors were able to acquire 4d CBCTs free of motion blurring. For scans based on the EM tracking system, reconstruction artifacts stemming from the presence of the EM-array and the EM-transponders were greatly reduced using newly developed correction algorithms. By tuning the imaging frequency independently for each respiratory phase prior to acquisition, it was possible to harmonize the number of projections over respiratory phases. Depending on the breathing period (3.5 or 5 s) and the gantry rotation time (4 or 5 min), between ∼90 and 145

  18. Dynamical aspects of coupled Rossler systems: effects of noise

    NASA Astrophysics Data System (ADS)

    Pravitha, R.; Indic, P.; Nampoori, V. P. N.

    2002-02-01

    Nonlinear time series analysis is employed to study the complex behaviour exhibited by a coupled pair of Rossler systems. Dimensional analysis with emphasis on the topological correlation dimension and the Kolmogorov entropy of the system is carried out in the coupling parameter space. The regime of phase synchronization is identified and the extent of synchronization between the systems constituting the coupled system is quantified by the phase synchronization index. The effect of noise on the coupling between the systems is also investigated. An exhaustive study of the topological, dynamical and synchronization properties of the nonlinear system under consideration in its characteristic parameter space is attempted.

  19. Intrinsic functional brain mapping in reconstructed 4D magnetic susceptibility (χ) data space.

    PubMed

    Chen, Zikuan; Calhoun, Vince

    2015-02-15

    By solving an inverse problem of T2*-weighted magnetic resonance imaging for a dynamic fMRI study, we reconstruct a 4D magnetic susceptibility source (χ) data space for intrinsic functional mapping. A 4D phase dataset is calculated from a 4D complex fMRI dataset. The background field and phase wrapping effect are removed by a Laplacian technique. A 3D χ source map is reconstructed from a 3D phase image by a computed inverse MRI (CIMRI) scheme. A 4D χ data space is reconstructed by repeating the 3D χ source reconstruction for each time point. A functional map is calculated by a temporal correlation between voxel signals in the 4D χ space and the timecourse of the task paradigm. With a finger-tapping experiment, we obtain two 3D functional mappings in the 4D magnitude data space and in the reconstructed 4D χ data space. We find that the χ-based functional mapping reveals co-occurrence of bidirectional responses in a 3D activation map that is different from the conventional magnitude-based mapping. The χ-based functional mapping can also be achieved by a 3D deconvolution of a phase activation map. Based on a subject experimental comparison, we show that the 4D χ tomography method could produce a similar χ activation map as obtained by the 3D deconvolution method. By removing the dipole effect and other fMRI technological contaminations, 4D χ tomography provides a 4D χ data space that allows a more direct and truthful functional mapping of a brain activity. Published by Elsevier B.V.

  20. Effects of shear coupling on shear properties of wood

    Treesearch

    Jen Y. Liu

    2000-01-01

    Under pure shear loading, an off-axis element of orthotropic material such as pure wood undergoes both shear and normal deformations. The ratio of the shear strain to a normal strain is defined as the shear coupling coefficient associated with the direction of the normal strain. The effects of shear coupling on shear properties of wood as predicted by the orthotropic...

  1. Effect of coupling line design on the performance of direct coupled high-Tc SQUID magnetometers

    NASA Astrophysics Data System (ADS)

    Kim, In Seon; Yu, Kwon Kyu; Park, Yong Ki

    2004-03-01

    YBCO dc SQUID magnetometers based on bicrystal Josephson junctions on 10 mm × 10 mm STO substrates have been fabricated. We have designed 16-parallel-loop pickup coil SQUID magnetometers with 50 μ m line width for use under a magnetically disturbed environment. The magnetometers exhibit stable flux locked loop operation under magnetically very noisy laboratory environment. We modified the coupling scheme between pickup coil and SQUID washer to replace the conventional narrow and long interconnection lines to reduce the residual inductance of the coupling lines. With the coupling line modification the effective area increased more than 12%. Finally, we could obtain optimized direct coupled YBCO SQUID magnetometer design having field sensitivity B_Φ of 4.5 nT/Φ 0 and magnetic field noise BN of 30 fT/Hz^1/2 measured at 100 Hz.

  2. COUPLING

    DOEpatents

    Frisch, E.; Johnson, C.G.

    1962-05-15

    A detachable coupling arrangement is described which provides for varying the length of the handle of a tool used in relatively narrow channels. The arrangement consists of mating the key and keyhole formations in the cooperating handle sections. (AEC)

  3. Experimental determination of the effective strong coupling constant

    SciTech Connect

    Alexandre Deur; Volker Burkert; Jian-Ping Chen; Wolfgang Korsch

    2007-07-01

    We extract an effective strong coupling constant from low Q{sup 2} data on the Bjorken sum. Using sum rules, we establish its Q{sup 2}-behavior over the complete Q{sup 2}-range. The result is compared to effective coupling constants extracted from different processes and to calculations based on Schwinger-Dyson equations, hadron spectroscopy or lattice QCD. Although the connection between the experimentally extracted effective coupling constant and the calculations is not clear, the results agree surprisingly well.

  4. Segmentation of 4D echocardiography using stochastic online dictionary learning.

    PubMed

    Huang, Xiaojie; Dione, Donald P; Lin, Ben A; Bregasi, Alda; Sinusas, Albert J; Duncan, James S

    2013-01-01

    Dictionary learning has been shown to be effective in exploiting spatiotemporal coherence for echocardiographic segmentation. To overcome the limitations of previous methods, we present a stochastic online dictionary learning approach for segmenting left ventricular borders from 4D echocardiography. It is based on stochastic approximations and processes a mini-batch of samples at a time, which results in lower memory consumption and lower computational cost than classical batch algorithms. In contrast to the previous methods, where dictionaries and their weights are optimized only on the most recently segmented frame, our stochastic online learning procedure optimizes the dictionaries and the corresponding weights by aggregating all the past information while adapting them to the dynamically changing data. The rate of updating the past information is controlled and varied according to the appearance scale to seek a balance between old and new information. Results on 26 4D echocardiographic images show the proposed method is more accurate, more robust, and faster than the previous batch algorithm.

  5. 4D Simulation of Explosive Eruption Dynamics at Vesuvius

    NASA Astrophysics Data System (ADS)

    Neri, A.; Esposti Ongaro, T.; Menconi, G.; de'Michieli Vitturi, M.; Cavazzoni, C.; Erbacci, G.; Baxter, P. J.

    2006-12-01

    We applied, using a supercomputer, a new simulation model based on fundamental transport laws to describe the 4D (3D spatial co-ordinates plus time) multiphase flow dynamics of explosive eruptions. The model solves the fundamental transport equations for a multiphase mixture formed by a continuous multi-component gas phase and n solid particulate phases representative of magma fragments (such as ash, crystals, and lapilli). Numerical simulations describe the collapse of the volcanic eruption column and the propagation of pyroclastic density currents, for selected medium scale (sub-Plinian) eruptive scenarios at Vesuvius, Italy. The study shows that 4D multiphase numerical models can illuminate the non-intuitive and internal dynamics of explosive eruptions that cannot otherwise be studied by direct observation or using previous models. In particular, simulations provide crucial insights into the effects of the generation mechanism of the flows - partial collapse vs boiling-over - on their hazard potential, the complex dynamics of the collapsing column, and the influence of Mount Somma on the propagation of PDCs into the circum-Vesuvian area, one of the world's most hazardous volcanic settings.

  6. Surface coupling effects on the capacitance of thin insulating films

    NASA Astrophysics Data System (ADS)

    Jamali, Tayeb; Farahani, S. Vasheghani; Jannesar, Mona; Palasantzas, George; Jafari, G. R.

    2015-05-01

    A general form for the surface roughness effects on the capacitance of a capacitor is proposed. We state that a capacitor with two uncoupled rough surfaces could be treated as two capacitors in series which have been divided from the mother capacitor by a slit. This is in contrast to the case where the two rough surfaces are coupled. When the rough surfaces are coupled, the type of coupling decides the modification of the capacitance in comparison to the uncoupled case. It is shown that if the coupling between the two surfaces of the capacitor is positive (negative), the capacitance is less (higher) than the case of two uncoupled rough plates. Also, we state that when the correlation length and the roughness exponent are small, the coupling effect is not negligible.

  7. Weight of the evidence on the human carcinogenicity of 2,4-D*

    PubMed Central

    Ibrahim, M. A.; Bond, G. G.; Burke, T. A.; Cole, P.; Dost, F. N.; Enterline, P. E.; Gough, M.; Greenberg, R. S.; Halperin, W. E.; McConnell, E.; Munro, I. C.; Swenberg, J. A.; Zahm, S. H.; Graham, J. D.

    1991-01-01

    The phenoxy herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) is widely used to control the growth of weeds and broadleaf plants. We convened a panel of 13 scientists to weigh the evidence on the human carcinogenicity of 2,4-D. The panel based its findings on a review of the toxicological and epidemiological literature on 2,4-D and related phenoxy herbicides. The toxicological data do not provide a strong basis for predicting that 2,4-D is a human carcinogen. Although a cause–effect relationship is far from being established, the epidemiological evidence for an association between exposure to 2,4-D and non–Hodgkin's lymphoma is suggestive and requires further investigation. There is little evidence of an association between use of 2,4-D and soft-tissue sarcoma or Hodgkin's disease, and no evidence of an association between 2,4-D use and any other form of cancer. Scientists on the panel were asked to categorize 2,4-D as a “known,” “probable,” “possible,” or “unlikely” carcinogen or as a noncarcinogen in humans. The predominant opinion among the panel members was that the weight of the evidence indicates that it is possible that exposure to 2,4-D can cause cancer in humans, although not all of the panelists believed the possibility was equally likely: one thought the possibility was strong, leaning toward probable, and five thought the possibility was remote, leaning toward unlikely. Two panelists believed it unlikely that 2,4-D can cause cancer in humans. PMID:1820267

  8. The impact of laterally coupled grating microstructure on effective coupling coefficients.

    PubMed

    Millett, R; Hinzer, K; Benhsaien, A; Hall, T J; Schriemer, H

    2010-04-02

    Lithographic fabrication may be used to define laterally coupled gratings of high refractive index contrast on waveguide ridges, eliminating the need for regrowth steps in such distributed feedback lasers. These may be made more amenable to fabrication by employing higher-order gratings. Reliable exploration of the laser design space requires that the radiating partial waves be accurately incorporated in numerical simulations. We modify the coupled-mode approach to fully consider the two-dimensional cross section, analyzing rectangular, sinusoidal, triangular and trapezoidal grating shapes. Effective coupling coefficients are determined for grating orders from first to third. We show that, by tailoring the grating microstructure, effective coupling coefficients up to double that of a 0.5 duty cycle rectangular grating can be achieved. The actual grating microstructure of an as-fabricated grating was analyzed and its effective coupling coefficient predicted as [Formula: see text]. This was found to be in excellent agreement with the value extracted from the amplified spontaneous emission spectrum, [Formula: see text].

  9. 17 CFR 260.4d-8 - Content.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 17 Commodity and Securities Exchanges 4 2014-04-01 2014-04-01 false Content. 260.4d-8 Section 260.4d-8 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION (CONTINUED) GENERAL RULES AND REGULATIONS, TRUST INDENTURE ACT OF 1939 Rules Under Section 304 § 260.4d-8 Content. (a) Each application for an order under section 304(d)...

  10. 17 CFR 260.4d-8 - Content.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Content. 260.4d-8 Section 260.4d-8 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION (CONTINUED) GENERAL RULES AND REGULATIONS, TRUST INDENTURE ACT OF 1939 Rules Under Section 304 § 260.4d-8 Content. (a) Each application for an order under section 304(d)...

  11. 17 CFR 260.4d-8 - Content.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 17 Commodity and Securities Exchanges 3 2013-04-01 2013-04-01 false Content. 260.4d-8 Section 260.4d-8 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION (CONTINUED) GENERAL RULES AND REGULATIONS, TRUST INDENTURE ACT OF 1939 Rules Under Section 304 § 260.4d-8 Content. (a) Each application for an order under section 304(d)...

  12. Killing Weeds with 2,4-D. Extension Bulletin 389.

    ERIC Educational Resources Information Center

    Lee, Oliver C.

    Discussed is the use of the herbicide 2,4-D. Though written for farmers and agricultural workers, the pamphlet considers turf weed control and use of 2,4-D near ornamental plants. Aspects of the use of this herbicide covered are: (1) the common forms of 2,4-D; (2) plant responses and tolerances to the herbicide; (3) dilution and concentration of…

  13. The 4D-TECS integration for NASA TSRV airplane

    NASA Technical Reports Server (NTRS)

    Kaminer, I.; Oshaughnessy, P. R.

    1989-01-01

    The integration of the Total Energy Control System (TECS) concept with 4D navigation is described. This integration was made to increase the operational capacity of modern aircraft and encourage incorporation of this increased capability with the evolving National Airspace System (NAS). Described herein is: 4D smoothing, the basic concepts of TECS, the spoiler integration concept, an algorithm for nulling out time error, speed and altitude profile modes, manual spoiler implementation, 4D logic, and the results of linear and nonlinear analysis.

  14. Killing Weeds with 2,4-D. Extension Bulletin 389.

    ERIC Educational Resources Information Center

    Lee, Oliver C.

    Discussed is the use of the herbicide 2,4-D. Though written for farmers and agricultural workers, the pamphlet considers turf weed control and use of 2,4-D near ornamental plants. Aspects of the use of this herbicide covered are: (1) the common forms of 2,4-D; (2) plant responses and tolerances to the herbicide; (3) dilution and concentration of…

  15. A 4D-QSAR study on anti-HIV HEPT analogues.

    PubMed

    Bak, Andrzej; Polanski, Jaroslaw

    2006-01-01

    We used the 4D-QSAR method coupled with the PLS analysis and uninformative variable elimination or its variants for the investigations of the antiviral activity of HEPT, a series of conformationally flexible molecules that bind HIV-1 reverse transcriptase. An analysis of several Hopfinger's and SOM-4D-QSAR models indicated that both methods yield comparable results. Generally, charge descriptors provide better modeling efficiency. We have shown that the method properly indicates the mode of interaction revealed by X-ray studies. It also allows us to calculate highly predictive QSAR models.

  16. Quantification of causal couplings via dynamical effects: a unifying perspective.

    PubMed

    Smirnov, Dmitry A

    2014-12-01

    Quantitative characterization of causal couplings from time series is crucial in studies of complex systems of different origin. Various statistical tools for that exist and new ones are still being developed with a tendency to creating a single, universal, model-free quantifier of coupling strength. However, a clear and generally applicable way of interpreting such universal characteristics is lacking. This work suggests a general conceptual framework for causal coupling quantification, which is based on state space models and extends the concepts of virtual interventions and dynamical causal effects. Namely, two basic kinds of interventions (state space and parametric) and effects (orbital or transient and stationary or limit) are introduced, giving four families of coupling characteristics. The framework provides a unifying view of apparently different well-established measures and allows us to introduce new characteristics, always with a definite "intervention-effect" interpretation. It is shown that diverse characteristics cannot be reduced to any single coupling strength quantifier and their interpretation is inevitably model based. The proposed set of dynamical causal effect measures quantifies different aspects of "how the coupling manifests itself in the dynamics," reformulating the very question about the "causal coupling strength."

  17. Mitotic activation of the DISC1-inducible cyclic AMP phosphodiesterase-4D9 (PDE4D9), through multi-site phosphorylation, influences cell cycle progression.

    PubMed

    Sheppard, Catherine L; Lee, Louisa C Y; Hill, Elaine V; Henderson, David J P; Anthony, Diana F; Houslay, Daniel M; Yalla, Krishna C; Cairns, Lynne S; Dunlop, Allan J; Baillie, George S; Huston, Elaine; Houslay, Miles D

    2014-09-01

    In Rat-1 cells, the dramatic decrease in the levels of both intracellular cyclic 3'5' adenosine monophosphate (cyclic AMP; cAMP) and in the activity of cAMP-activated protein kinase A (PKA) observed in mitosis was paralleled by a profound increase in cAMP hydrolyzing phosphodiesterase-4 (PDE4) activity. The decrease in PKA activity, which occurs during mitosis, was attributable to PDE4 activation as the PDE4 selective inhibitor, rolipram, but not the phosphodiesterase-3 (PDE3) inhibitor, cilostamide, specifically ablated this cell cycle-dependent effect. PDE4 inhibition caused Rat-1 cells to move from S phase into G2/M more rapidly, to transit through G2/M more quickly and to remain in G1 for a longer period. Inhibition of PDE3 elicited no observable effects on cell cycle dynamics. Selective immunopurification of each of the four PDE4 sub-families identified PDE4D as being selectively activated in mitosis. Subsequent analysis uncovered PDE4D9, an isoform whose expression can be regulated by Disrupted-In-Schizophrenia 1 (DISC1)/activating transcription factor 4 (ATF4) complex, as the sole PDE4 species activated during mitosis in Rat-1 cells. PDE4D9 becomes activated in mitosis through dual phosphorylation at Ser585 and Ser245, involving the combined action of ERK and an unidentified 'switch' kinase that has previously been shown to be activated by H2O2. Additionally, in mitosis, PDE4D9 also becomes phosphorylated at Ser67 and Ser81, through the action of MK2 (MAPKAPK2) and AMP kinase (AMPK), respectively. The multisite phosphorylation of PDE4D9 by all four of these protein kinases leads to decreased mobility (band-shift) of PDE4D9 on SDS-PAGE. PDE4D9 is predominantly concentrated in the perinuclear region of Rat-1 cells but with a fraction distributed asymmetrically at the cell margins. Our investigations demonstrate that the diminished levels of cAMP and PKA activity that characterise mitosis are due to enhanced cAMP degradation by PDE4D9. PDE4D9, was found to

  18. Photodegradation of 2,4-D induced by NO₂(-) in aqueous solutions: the role of NO₂.

    PubMed

    Yu, Chunyan; Wang, Hua; Liu, Xuan; Quan, Xie; Chen, Shuo; Zhang, Jianlin; Zhang, Peng

    2014-07-01

    To elucidate the effect of nitrite ion (NO₂(-)) on the photodegradation of organic pollutants, a 300 W mercury lamp and Pyrex tubes restricting the transmission of wavelengths below 290 nm were used to simulate sunlight, and the photodegradation processes of 2,4-dichlorophenoxyacetic acid (2,4-D) with different concentrations of NO₂(-) in freshwater and seawater were studied. The effect of reactive oxygen species (ROS) on the photolysis of 2,4-D was also demonstrated using electron paramagnetic resonance (EPR). The results indicated that the 2,4-D photolysis reaction followed the first-order kinetics in freshwater and seawater under different concentrations of NO₂(-). Meanwhile, the photochemical reaction rate of 2,4-D increased with increasing concentration of NO₂(-). When the concentration of NO₂(-) was lower than 23 mg/L, the photodegradation rate of 2,4-D in seawater was higher than that in freshwater. However, when the concentration of NO₂(-) was reached 230 mg/L, 2,4-D degradation slowed down in seawater. It was important to note that EPR spectra showed NO₂ radical was generated in the NO₂(-) solution under simulated sunlight irradiation, indicating that 2,4-D photodegradation could be induced by NO₂. These results show the key role of NO₂(-) in photochemistry and are helpful for better understanding of the phototransformation of environmental contaminants in natural aquatic systems. Copyright © 2014. Published by Elsevier B.V.

  19. Pros and cons for C4d as a biomarker

    PubMed Central

    Cohen, Danielle; Colvin, Robert B.; Daha, Mohamed R.; Drachenberg, Cinthia B.; Haas, Mark; Nickeleit, Volker; Salmon, Jane E.; Sis, Banu; Zhao, Ming-Hui; Bruijn, Jan A.; Bajema, Ingeborg M.

    2013-01-01

    The introduction of C4d in daily clinical practice in the late nineties aroused an ever-increasing interest in the role of antibody-mediated mechanisms in allograft rejection. As a marker of classical complement activation, C4d made it possible to visualize the direct link between anti-donor antibodies and tissue injury at sites of antibody binding in a graft. With the expanding use of C4d worldwide several limitations of C4d were identified. For instance, in ABO-incompatible transplantations C4d is present in the majority of grafts but this seems to point at ‘graft accommodation’ rather than antibody-mediated rejection. C4d is now increasingly recognized as a potential biomarker in other fields where antibodies can cause tissue damage, such as systemic autoimmune diseases and pregnancy. In all these fields, C4d holds promise to detect patients at risk for the consequences of antibody-mediated disease. Moreover, the emergence of new therapeutics that block complement activation makes C4d a marker with potential to identify patients who may possibly benefit from these drugs. This review provides an overview of the past, present, and future perspectives of C4d as a biomarker, focusing on its use in solid organ transplantation and discussing its possible new roles in autoimmunity and pregnancy. PMID:22297669

  20. Effects of structural coupling on mistuned cascade flutter and response

    NASA Technical Reports Server (NTRS)

    Kielb, R. E.; Kaza, K. R. V.

    1983-01-01

    The effects of structural coupling on mistuned cascade flutter and response are analytically investigated using an extended typical section model. This model includes both structural and aerodynamic coupling between the blades. The model assumes that the structurally coupled system natural modes were determined and are represented in the form of N bending and N torsional uncoupled modes for each blade, where N is the number of blades and, hence, is only valid for blade dominated motion. The aerodynamic loads are calculated by using two dimensional unsteady cascade theories in the subsonic and supersonic flow regimes. The results show that the addition of structural coupling can affect both the aeroelastic stability and frequency. The stability is significantly affected only when the system is mistuned. The resonant frequencies can be significantly changed by structural coupling in both tuned and mistuned systems, however, the peak response is significantly affected only in the latter.

  1. 4D dose simulation in volumetric arc therapy: Accuracy and affecting parameters

    PubMed Central

    Werner, René

    2017-01-01

    between 98% and 100%. Parameters of major influence on 4D VMAT dose simulation accuracy were the degree of temporal discretization of the dose delivery process (the higher, the better) and correct alignment of the assumed breathing phases at the beginning of the dose measurements and simulations. Given the high γ-passing rates between simulated motion-affected doses and dynamic measurements, we consider the simulations to provide a reliable basis for assessment of VMAT motion effects that–in the sense of 4D QA of VMAT treatment plans–allows to verify target coverage in hypofractioned VMAT-based radiotherapy of moving targets. Remaining differences between measurements and simulations motivate, however, further detailed studies. PMID:28231337

  2. 4D dose simulation in volumetric arc therapy: Accuracy and affecting parameters.

    PubMed

    Sothmann, Thilo; Gauer, Tobias; Werner, René

    2017-01-01

    between 98% and 100%. Parameters of major influence on 4D VMAT dose simulation accuracy were the degree of temporal discretization of the dose delivery process (the higher, the better) and correct alignment of the assumed breathing phases at the beginning of the dose measurements and simulations. Given the high γ-passing rates between simulated motion-affected doses and dynamic measurements, we consider the simulations to provide a reliable basis for assessment of VMAT motion effects that-in the sense of 4D QA of VMAT treatment plans-allows to verify target coverage in hypofractioned VMAT-based radiotherapy of moving targets. Remaining differences between measurements and simulations motivate, however, further detailed studies.

  3. Advanced treatment planning using direct 4D optimisation for pencil-beam scanned particle therapy

    NASA Astrophysics Data System (ADS)

    Bernatowicz, Kinga; Zhang, Ye; Perrin, Rosalind; Weber, Damien C.; Lomax, Antony J.

    2017-08-01

    We report on development of a new four-dimensional (4D) optimisation approach for scanned proton beams, which incorporates both irregular motion patterns and the delivery dynamics of the treatment machine into the plan optimiser. Furthermore, we assess the effectiveness of this technique to reduce dose to critical structures in proximity to moving targets, while maintaining effective target dose homogeneity and coverage. The proposed approach has been tested using both a simulated phantom and a clinical liver cancer case, and allows for realistic 4D calculations and optimisation using irregular breathing patterns extracted from e.g. 4DCT-MRI (4D computed tomography-magnetic resonance imaging). 4D dose distributions resulting from our 4D optimisation can achieve almost the same quality as static plans, independent of the studied geometry/anatomy or selected motion (regular and irregular). Additionally, current implementation of the 4D optimisation approach requires less than 3 min to find the solution for a single field planned on 4DCT of a liver cancer patient. Although 4D optimisation allows for realistic calculations using irregular breathing patterns, it is very sensitive to variations from the planned motion. Based on a sensitivity analysis, target dose homogeneity comparable to static plans (D5-D95  <5%) has been found only for differences in amplitude of up to 1 mm, for changes in respiratory phase  <200 ms and for changes in the breathing period of  <20 ms in comparison to the motions used during optimisation. As such, methods to robustly deliver 4D optimised plans employing 4D intensity-modulated delivery are discussed.

  4. Broadband Noise of Fans - With Unsteady Coupling Theory to Account for Rotor and Stator Reflection/Transmission Effects

    NASA Technical Reports Server (NTRS)

    Hanson, Donald B.

    2001-01-01

    This report examines the effects on broadband noise generation of unsteady coupling between a rotor and stator in the fan stage of a turbofan engine. Whereas previous acoustic analyses treated the blade rows as isolated cascades, the present work accounts for reflection and transmission effects at both blade rows by tracking the mode and frequency scattering of pressure and vortical waves. The fan stage is modeled in rectilinear geometry to take advantage of a previously existing unsteady cascade theory for 3D perturbation waves and thereby use a realistic 3D turbulence spectrum. In the analysis, it was found that the set of participating modes divides itself naturally into "independent mode subsets" that couple only among themselves and not to the other such subsets. This principle is the basis for the analysis and considerably reduces computational effort. It also provides a simple, accurate scheme for modal averaging for further efficiency. Computed results for a coupled fan stage are compared with calculations for isolated blade rows. It is found that coupling increases downstream noise by 2 to 4 dB. Upstream noise is lower for isolated cascades and is further reduced by including coupling effects. In comparison with test data, the increase in the upstream/downstream differential indicates that broadband noise from turbulent inflow at the stator dominates downstream noise but is not a significant contributor to upstream noise.

  5. Optical control of coupled molecular states by ac Stark effect

    NASA Astrophysics Data System (ADS)

    Qi, Jianbing

    2014-05-01

    Quantum states with different spin multiplicity can be coupled through the interaction of the spin orbital motion of electrons. For example, the spin-orbit coupled rovibrational levels in diatomic alkali, which have different multiplicity in terms of total spin quantum number, and are classified as singlet states (if the total spin is zero) and triplet states (if the total spin is one), respectively. A transition from the singlet level can only go to singlet levels and a triplet only to triplet levels. Due to the spin-orbit coupling, however, the coupled states mix each other, therefore both states have singlet as well as triplet character. By coherently coupling the pair to an auxiliary quantum state, varying the Rabi frequency of the coupling laser and the detuning of the laser frequency, the coupling of the two mixed singlet-triplet molecular rovibrational levels can be modified by ac Stark effect. We use density matrix equations and a five-level molecular model to show that a coupled singlet-triplet pair of rovibrational levels can be used as a channel to optically control quantum states.

  6. Digit ratio (2D:4D) and performance in Indian swimmers.

    PubMed

    Sudhakar, H H; Veena, Umesh B; Tejaswi, R Nadig

    2013-01-01

    It has been suggested that achievement in sports is correlated with a putative measure of prenatal testosterone the 2nd to 4th digit ratio (2D:4D). It has been shown that digit ratio (2D:4D) is negatively associated with prenatal testosterone, and it is also negatively associated with ability in sports. This study examined associations between 2D:4D and performance of both male and female National level Indian swimmers. Age matched non-sports personnel formed the control. Lengths of second and fourth digits were measured after scanning both hands and their ratio calculated. Our results show lower 2D:4D values in males compared to females (P < 0.05). Among male, but not female, swimmers had significantly (P < 0.05) lower 2D:4D ratio. Low 2D:4D in male swimmers suggests they are more prenatally programmed via long-lasting extra genital effects of testosterone. 2D:4D ratio could be used to identify young sports personnel who have potential to reach high levels of performance.

  7. 4D simulation of explosive eruption dynamics at Vesuvius

    NASA Astrophysics Data System (ADS)

    Neri, Augusto; Esposti Ongaro, Tomaso; Menconi, Gianluca; De'Michieli Vitturi, Mattia; Cavazzoni, Carlo; Erbacci, Giovanni; Baxter, Peter J.

    2007-02-01

    We applied a new simulation model, based on multiphase transport laws, to describe the 4D (3D spatial coordinates plus time) dynamics of explosive eruptions. Numerical experiments, carried out on a parallel supercomputer, describe the collapse of the volcanic eruption column and the propagation of pyroclastic density currents (PDCs), for selected medium scale (sub-Plinian) eruptive scenarios at Vesuvius, Italy. Simulations provide crucial insights into the effects of the generation mechanism of the flows - partial collapse vs boiling-over - on their evolution and hazard potential, the unstable dynamics of the fountain, and the influence of Mount Somma on the propagation of PDCs into the circum-Vesuvian area, one of the world's most hazardous volcanic settings. Results also show that it is possible to characterize the volcanic column behavior in terms of percentage of the mass of pyroclasts collapsed to the ground and how this parameter strongly influences the dynamics and hazard of the associated PDCs.

  8. Immediate effect of couple relationship education on low-satisfaction couples: a randomized clinical trial plus an uncontrolled trial replication.

    PubMed

    Kim Halford, W; Pepping, Christopher A; Hilpert, Peter; Bodenmann, Guy; Wilson, Keithia L; Busby, Dean; Larson, Jeffry; Holman, Thomas

    2015-05-01

    Couple relationship education (RE) usually is conceived of as relationship enhancement for currently satisfied couples, with a goal of helping couples sustain satisfaction. However, RE also might be useful as a brief, accessible intervention for couples with low satisfaction. Two studies were conducted that tested whether couples with low relationship satisfaction show meaningful gains after RE. Study 1 was a three-condition randomized controlled trial in which 182 couples were randomly assigned to RELATE with Couple CARE (RCC), a flexible delivery education program for couples, or one of two control conditions. Couples with initially low satisfaction receiving RCC showed a moderate increase in relationship satisfaction (d=0.50) relative to the control. In contrast, couples initially high in satisfaction showed little change and there was no difference between RCC and the control conditions. Study 2 was an uncontrolled trial of the Couple Coping Enhancement Training (CCET) administered to 119 couples. Couples receiving CCET that had initially low satisfaction showed a moderate increase in satisfaction (g=.44), whereas initially highly satisfied couples showed no change. Brief relationship education can assist somewhat distressed couples to enhance satisfaction, and has potential as a cost-effective way of enhancing the reach of couple interventions.

  9. Magnetic dipole transitions in 4d{sup N} configurations of tungsten ions

    SciTech Connect

    Jonauskas, V.; Kisielius, R.; Kyniene, A.; Kucas, S.; Norrington, P. H.

    2010-01-15

    Magnetic dipole transitions between the levels of ground 4d{sup N} configurations of tungsten ions were analyzed by employing a large basis of interacting configurations. Previously introduced configuration interaction strength between two configurations was used to determine the configurations with the largest contribution to wave functions of atomic states for the considered configurations. Collisional-radiative modeling was performed for the levels of the ground configuration coupled through electric dipole transitions with 4p{sup 5}4d{sup N+1} and 4d{sup N-1}4f configurations. New identification of some lines observed in the electron-beam ion trap plasma was proposed based on calculations in which wavelength convergence was reached.

  10. X-ray emissions in 3d, 4d, and 5d ranges for uranium ions

    SciTech Connect

    Bonnelle, C.; Jonnard, P.; Barre, C.; Giorgi, G.; Bruneau, J.

    1997-05-01

    Radiative decay of nd{sup {minus}1}5f{sup m+1} excited states in UO{sub 2} induced by electron collisions is studied theoretically and experimentally. Energies, transition probabilities, and photoexcitation cross sections for the relevant configurations of U{sup 4+} are calculated by using the multiconfiguration Dirac-Fock method. Experimental observations are made in the 4d range. Direct recombination of the excited 5f electron to the 4d hole and 4d-6p emission in the presence of the spectator excited 5f electron are observed. From the theoretical results, the spectra are simulated and compared to the observed spectra in the three nd regions. The agreement is correct and describes the evolution of the coupling scheme in the nd{sup {minus}1}5f{sup 3} excited states from n=3 to n=5. {copyright} {ital 1997} {ital The American Physical Society}

  11. Biokinetic Analysis and Metabolic Fate of 2,4-D in 2,4-D-Resistant Soybean (Glycine max).

    PubMed

    Skelton, Joshua J; Simpson, David M; Peterson, Mark A; Riechers, Dean E

    2017-07-26

    The Enlist weed control system allows the use of 2,4-D in soybean but slight necrosis in treated leaves may be observed in the field. The objectives of this research were to measure and compare uptake, translocation, and metabolism of 2,4-D in Enlist (E, resistant) and non-AAD-12 transformed (NT, sensitive) soybeans. The adjuvant from the Enlist Duo herbicide formulation (ADJ) increased 2,4-D uptake (36%) and displayed the fastest rate of uptake (U50= 0.2 h) among treatments. E soybean demonstrated a faster rate of 2,4-D metabolism (M50= 0.2 h) compared to NT soybean, but glyphosate did not affect 2,4-D metabolism. Metabolites of 2,4-D in E soybean were qualitatively different than NT. Applying 2,4-D-ethylhexyl ester instead of 2,4-D choline (a quaternary ammonium salt) eliminated visual injury to E soybean, likely due to the time required for initial de-esterification and bioactivation. Excessive 2,4-D acid concentrations in E soybean resulting from ADJ-increased uptake may significantly contribute to foliar injury.

  12. 32 CFR 1645.4 - Exclusion from Class 4-D.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... MINISTERS OF RELIGION § 1645.4 Exclusion from Class 4-D. A registrant is excluded from Class 4-D when his... duly ordained minister of religion in accordance with the ceremonial rite or discipline of a church... principles of religion and administer the ordinances of public worship, as embodied in the creed or...

  13. 32 CFR 1645.4 - Exclusion from Class 4-D.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... MINISTERS OF RELIGION § 1645.4 Exclusion from Class 4-D. A registrant is excluded from Class 4-D when his... duly ordained minister of religion in accordance with the ceremonial rite or discipline of a church... principles of religion and administer the ordinances of public worship, as embodied in the creed or...

  14. 4D Printing with Mechanically Robust, Thermally Actuating Hydrogels.

    PubMed

    Bakarich, Shannon E; Gorkin, Robert; in het Panhuis, Marc; Spinks, Geoffrey M

    2015-06-01

    A smart valve is created by 4D printing of hydrogels that are both mechanically robust and thermally actuating. The printed hydrogels are made up of an interpenetrating network of alginate and poly(N-isopropylacrylamide). 4D structures are created by printing the "dynamic" hydrogel ink alongside other static materials.

  15. 32 CFR 1645.4 - Exclusion from Class 4-D.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... MINISTERS OF RELIGION § 1645.4 Exclusion from Class 4-D. A registrant is excluded from Class 4-D when his... duly ordained minister of religion in accordance with the ceremonial rite or discipline of a church... principles of religion and administer the ordinances of public worship, as embodied in the creed or...

  16. 32 CFR 1645.4 - Exclusion from Class 4-D.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... MINISTERS OF RELIGION § 1645.4 Exclusion from Class 4-D. A registrant is excluded from Class 4-D when his... duly ordained minister of religion in accordance with the ceremonial rite or discipline of a church... principles of religion and administer the ordinances of public worship, as embodied in the creed or...

  17. 32 CFR 1645.4 - Exclusion from Class 4-D.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... MINISTERS OF RELIGION § 1645.4 Exclusion from Class 4-D. A registrant is excluded from Class 4-D when his... duly ordained minister of religion in accordance with the ceremonial rite or discipline of a church... principles of religion and administer the ordinances of public worship, as embodied in the creed or...

  18. 4D Light Field Imaging System Using Programmable Aperture

    NASA Technical Reports Server (NTRS)

    Bae, Youngsam

    2012-01-01

    Complete depth information can be extracted from analyzing all angles of light rays emanated from a source. However, this angular information is lost in a typical 2D imaging system. In order to record this information, a standard stereo imaging system uses two cameras to obtain information from two view angles. Sometimes, more cameras are used to obtain information from more angles. However, a 4D light field imaging technique can achieve this multiple-camera effect through a single-lens camera. Two methods are available for this: one using a microlens array, and the other using a moving aperture. The moving-aperture method can obtain more complete stereo information. The existing literature suggests a modified liquid crystal panel [LC (liquid crystal) panel, similar to ones commonly used in the display industry] to achieve a moving aperture. However, LC panels cannot withstand harsh environments and are not qualified for spaceflight. In this regard, different hardware is proposed for the moving aperture. A digital micromirror device (DMD) will replace the liquid crystal. This will be qualified for harsh environments for the 4D light field imaging. This will enable an imager to record near-complete stereo information. The approach to building a proof-ofconcept is using existing, or slightly modified, off-the-shelf components. An SLR (single-lens reflex) lens system, which typically has a large aperture for fast imaging, will be modified. The lens system will be arranged so that DMD can be integrated. The shape of aperture will be programmed for single-viewpoint imaging, multiple-viewpoint imaging, and coded aperture imaging. The novelty lies in using a DMD instead of a LC panel to move the apertures for 4D light field imaging. The DMD uses reflecting mirrors, so any light transmission lost (which would be expected from the LC panel) will be minimal. Also, the MEMS-based DMD can withstand higher temperature and pressure fluctuation than a LC panel can. Robotics need

  19. Effect of spin rotation coupling on spin transport

    SciTech Connect

    Chowdhury, Debashree Basu, B.

    2013-12-15

    We have studied the spin rotation coupling (SRC) as an ingredient to explain different spin-related issues. This special kind of coupling can play the role of a Dresselhaus like coupling in certain conditions. Consequently, one can control the spin splitting, induced by the Dresselhaus like term, which is unusual in a semiconductor heterostructure. Within this framework, we also study the renormalization of the spin-dependent electric field and spin current due to the k{sup →}⋅p{sup →} perturbation, by taking into account the interband mixing in the rotating system. In this paper we predict the enhancement of the spin-dependent electric field resulting from the renormalized spin rotation coupling. The renormalization factor of the spin electric field is different from that of the SRC or Zeeman coupling. The effect of renormalized SRC on spin current and Berry curvature is also studied. Interestingly, in the presence of this SRC-induced SOC it is possible to describe spin splitting as well as spin galvanic effect in semiconductors. -- Highlights: •Studied effect of spin rotation coupling on the spin electric field, spin current and Berry curvature. •In the k{sup →}⋅p{sup →} framework we study the renormalization of spin electric field and spin current. •For an inertial system we have discussed the spin splitting. •Expression for the Berry phase in the inertial system is discussed. •The inertial spin galvanic effect is studied.

  20. Clinical evaluation of 4D PET motion compensation strategies for treatment verification in ion beam therapy

    NASA Astrophysics Data System (ADS)

    Gianoli, Chiara; Kurz, Christopher; Riboldi, Marco; Bauer, Julia; Fontana, Giulia; Baroni, Guido; Debus, Jürgen; Parodi, Katia

    2016-06-01

    A clinical trial named PROMETHEUS is currently ongoing for inoperable hepatocellular carcinoma (HCC) at the Heidelberg Ion Beam Therapy Center (HIT, Germany). In this framework, 4D PET-CT datasets are acquired shortly after the therapeutic treatment to compare the irradiation induced PET image with a Monte Carlo PET prediction resulting from the simulation of treatment delivery. The extremely low count statistics of this measured PET image represents a major limitation of this technique, especially in presence of target motion. The purpose of the study is to investigate two different 4D PET motion compensation strategies towards the recovery of the whole count statistics for improved image quality of the 4D PET-CT datasets for PET-based treatment verification. The well-known 4D-MLEM reconstruction algorithm, embedding the motion compensation in the reconstruction process of 4D PET sinograms, was compared to a recently proposed pre-reconstruction motion compensation strategy, which operates in sinogram domain by applying the motion compensation to the 4D PET sinograms. With reference to phantom and patient datasets, advantages and drawbacks of the two 4D PET motion compensation strategies were identified. The 4D-MLEM algorithm was strongly affected by inverse inconsistency of the motion model but demonstrated the capability to mitigate the noise-break-up effects. Conversely, the pre-reconstruction warping showed less sensitivity to inverse inconsistency but also more noise in the reconstructed images. The comparison was performed by relying on quantification of PET activity and ion range difference, typically yielding similar results. The study demonstrated that treatment verification of moving targets could be accomplished by relying on the whole count statistics image quality, as obtained from the application of 4D PET motion compensation strategies. In particular, the pre-reconstruction warping was shown to represent a promising choice when combined with intra

  1. Clinical evaluation of 4D PET motion compensation strategies for treatment verification in ion beam therapy.

    PubMed

    Gianoli, Chiara; Kurz, Christopher; Riboldi, Marco; Bauer, Julia; Fontana, Giulia; Baroni, Guido; Debus, Jürgen; Parodi, Katia

    2016-06-07

    A clinical trial named PROMETHEUS is currently ongoing for inoperable hepatocellular carcinoma (HCC) at the Heidelberg Ion Beam Therapy Center (HIT, Germany). In this framework, 4D PET-CT datasets are acquired shortly after the therapeutic treatment to compare the irradiation induced PET image with a Monte Carlo PET prediction resulting from the simulation of treatment delivery. The extremely low count statistics of this measured PET image represents a major limitation of this technique, especially in presence of target motion. The purpose of the study is to investigate two different 4D PET motion compensation strategies towards the recovery of the whole count statistics for improved image quality of the 4D PET-CT datasets for PET-based treatment verification. The well-known 4D-MLEM reconstruction algorithm, embedding the motion compensation in the reconstruction process of 4D PET sinograms, was compared to a recently proposed pre-reconstruction motion compensation strategy, which operates in sinogram domain by applying the motion compensation to the 4D PET sinograms. With reference to phantom and patient datasets, advantages and drawbacks of the two 4D PET motion compensation strategies were identified. The 4D-MLEM algorithm was strongly affected by inverse inconsistency of the motion model but demonstrated the capability to mitigate the noise-break-up effects. Conversely, the pre-reconstruction warping showed less sensitivity to inverse inconsistency but also more noise in the reconstructed images. The comparison was performed by relying on quantification of PET activity and ion range difference, typically yielding similar results. The study demonstrated that treatment verification of moving targets could be accomplished by relying on the whole count statistics image quality, as obtained from the application of 4D PET motion compensation strategies. In particular, the pre-reconstruction warping was shown to represent a promising choice when combined with intra

  2. Autaptic effects on synchrony of neurons coupled by electrical synapses

    NASA Astrophysics Data System (ADS)

    Kim, Youngtae

    2017-07-01

    In this paper, we numerically study the effects of a special synapse known as autapse on synchronization of population of Morris-Lecar (ML) neurons coupled by electrical synapses. Several configurations of the ML neuronal populations such as a pair or a ring or a globally coupled network with and without autapses are examined. While most of the papers on the autaptic effects on synchronization have used networks of neurons of same spiking rate, we use the network of neurons of different spiking rates. We find that the optimal autaptic coupling strength and the autaptic time delay enhance synchronization in our neural networks. We use the phase response curve analysis to explain the enhanced synchronization by autapses. Our findings reveal the important relationship between the intraneuronal feedback loop and the interneuronal coupling.

  3. Human PDE4D isoform composition is deregulated in primary prostate cancer and indicative for disease progression and development of distant metastases

    PubMed Central

    Böttcher, René; Dulla, Kalyan; van Strijp, Dianne; Dits, Natasja; Verhoef, Esther I.; Baillie, George S.; van Leenders, Geert J.L.H.; Houslay, Miles D.; Jenster, Guido; Hoffmann, Ralf

    2016-01-01

    Phosphodiesterase 4D7 was recently shown to be specifically over-expressed in localized prostate cancer, raising the question as to which regulatory mechanisms are involved and whether other isoforms of this gene family (PDE4D) are affected under the same conditions. We investigated PDE4D isoform composition in prostatic tissues using a total of seven independent expression datasets and also included data on DNA methylation, copy number and AR and ERG binding in PDE4D promoters to gain insight into their effect on PDE4D transcription. We show that expression of PDE4D isoforms is consistently altered in primary human prostate cancer compared to benign tissue, with PDE4D7 being up-regulated while PDE4D5 and PDE4D9 are down-regulated. Disease progression is marked by an overall down-regulation of long PDE4D isoforms, while short isoforms (PDE4D1/2) appear to be relatively unaffected. While these alterations seem to be independent of copy number alterations in the PDE4D locus and driven by AR and ERG binding, we also observed increased DNA methylation in the promoter region of PDE4D5, indicating a long lasting alteration of the isoform composition in prostate cancer tissues. We propose two independent metrics that may serve as diagnostic and prognostic markers for prostate disease: (PDE4D7 - PDE4D5) provides an effective means for distinguishing PCa from normal adjacent prostate, whereas PDE4D1/2 - (PDE4D5 + PDE4D7 + PDE4D9) offers strong prognostic potential to detect aggressive forms of PCa and is associated with metastasis free survival. Overall, our findings highlight the relevance of PDE4D as prostate cancer biomarker and potential drug target. PMID:27683107

  4. Action-effect coupling in pianists.

    PubMed

    Drost, Ulrich C; Rieger, Martina; Brass, Marcel; Gunter, Thomas C; Prinz, Wolfgang

    2005-03-01

    Recent theories have stressed the role of effect anticipation in action control. Such a mechanism requires the prior acquisition of integrated action-effect associations. The strength of such associations should directly depend on the amount of learning, and therefore be most pronounced in motor experts. Using an interference paradigm, we investigated whether evidence of such representations can be demonstrated in expert pianists. Participants were required to play chords on a keyboard in response to imperative visual stimuli. Concurrently, task-irrelevant auditory stimuli ("potential" action effects) were presented that were congruent or incongruent with the chords to be played. In Experiment 1 we found evidence that expert pianists, compared with non-musicians, have acquired such action-effects representations. Response times were slower when the auditory stimulus was incongruent with the required response. In order to ascertain the locus of interference, we varied imperative stimuli and responses in Experiments 2 and 3. The results indicate that, for the most part, interference occurs on the response level rather than on an abstract level. However, the perception of action effects also evokes processing of abstract features, like the concept of major-minor mode.

  5. Effective quantum dynamics of interacting systems with inhomogeneous coupling

    SciTech Connect

    Lopez, C. E.; Retamal, J. C.; Christ, H.; Solano, E.

    2007-03-15

    We study the quantum dynamics of a single mode (particle) interacting inhomogeneously with a large number of particles and introduce an effective approach to find the accessible Hilbert space, where the dynamics takes place. Two relevant examples are given: the inhomogeneous Tavis-Cummings model (e.g., N atomic qubits coupled to a single cavity mode, or to a motional mode in trapped ions) and the inhomogeneous coupling of an electron spin to N nuclear spins in a quantum dot.

  6. Rashba spin-orbit coupling effects in armchair graphene nanoribbons

    SciTech Connect

    Prabhakar, S.; Melnik, R.; Sebetci, A.

    2015-03-30

    We study the influence of the Rashba spin-orbit coupling effects on the electronic properties of armchair graphene nanoribbons (GNRs). By utilizing both analytical and numerical schemes, we show that the finite width of the graphene nanoribbon breaks its energy spectrum into an infinite number of bands. By considering the Rashba spin-orbit coupling term as a perturbation, we show that zero energy bands between electron and hole states at Dirac points are lifted into a finite bandgap.

  7. Digit ratio (2D:4D) in Klinefelter's syndrome.

    PubMed

    Manning, J T; Kilduff, L P; Trivers, R

    2013-01-01

    The ratio of second to fourth digit length (2D:4D) is a correlate of prenatal testosterone. High 2D:4D is associated with low prenatal testosterone, and reduced sensitivity to testosterone. Klinefelter's syndrome (KS; 47 XXY) affects the endocrine system, such that low testosterone levels are found in KS foetuses, new-borns and adults. To date, there are no published data regarding the pattern of 2D:4D in KS males. Here we consider 2D:4D in KS individuals (n = 51), their relatives (16 fathers and 15 mothers) and an unaffected control sample of 153 men and 153 women. Adult KS individuals were taller than their fathers and had shorter fingers than fathers and male controls. Compared with fathers, male controls and mothers, KS males had shorter fingers relative to height. With regard to 2D:4D, KS individuals had higher 2D:4D than fathers (right and left hands), male controls (right and left hands) and mothers (left hands). Among KS males older than 13 years there were 34 individuals currently prescribed testosterone and nine not prescribed. In comparison to the former, the latter individuals had higher right 2D:4D and higher right-left 2D:4D. We conclude that KS males have mean 2D:4D values similar to those found in female population norms. In addition, testosterone supplementation in KS males may be most common for individuals with low right 2D:4D. © 2012 American Society of Andrology and European Academy of Andrology.

  8. 4D inversion of time-lapse magnetotelluric data sets for monitoring geothermal reservoir

    NASA Astrophysics Data System (ADS)

    Nam, Myung Jin; Song, Yoonho; Jang, Hannuree; Kim, Bitnarae

    2017-06-01

    The productivity of a geothermal reservoir, which is a function of the pore-space and fluid-flow path of the reservoir, varies since the properties of the reservoir changes with geothermal reservoir production. Because the variation in the reservoir properties causes changes in electrical resistivity, time-lapse (TL) three-dimensional (3D) magnetotelluric (MT) methods can be applied to monitor the productivity variation of a geothermal reservoir thanks to not only its sensitivity to the electrical resistivity but also its deep depth of survey penetration. For an accurate interpretation of TL MT-data sets, a four-dimensional (4D) MT inversion algorithm has been developed to simultaneously invert all vintage data considering time-coupling between vintages. However, the changes in electrical resistivity of deep geothermal reservoirs are usually small generating minimum variation in TL MT responses. Maximizing the sensitivity of inversion to the changes in resistivity is critical in the success of 4D MT inversion. Thus, we further developed a focused 4D MT inversion method by considering not only the location of a reservoir but also the distribution of newly-generated fractures during the production. For the evaluation of the 4D MT algorithm, we tested our 4D inversion algorithms using synthetic TL MT-data sets.

  9. Seeking the loop quantum gravity Barbero-Immirzi parameter and field in 4D, N=1 supergravity

    SciTech Connect

    Gates, S. James Jr.; Ketov, Sergei V.; Yunes, Nicolas

    2009-09-15

    We embed the loop quantum gravity Barbero-Immirzi parameter and field within an action describing 4D, N=1 supergravity and thus within a low-energy effective action of superstring/M theory. We use the fully gauge-covariant description of supergravity in (curved) superspace. The gravitational constant is replaced with the vacuum expectation value of a scalar field, which in local supersymmetry is promoted to a complex, covariantly chiral scalar superfield. The imaginary part of this superfield couples to a supersymmetric Holst term. The Holst term also serves as a starting point in the loop quantum gravity action. This suggest the possibility of a relation between loop quantum gravity and supersymmetric string theory, where the Barbero-Immirzi parameter and field of the former play the role of the supersymmetric axion in the latter. Adding matter fermions in loop quantum gravity may require the extension of the Holst action through the Nieh-Yan topological invariant, while in pure, matter-free supergravity their supersymmetric extensions are the same. We show that, when the Barbero-Immirzi parameter is promoted to a field in the context of 4D supergravity, it is equivalent to adding a dynamical complex chiral (dilaton-axion) superfield with a nontrivial kinetic term (or Kaehler potential), coupled to supergravity.

  10. Seeking the loop quantum gravity Barbero-Immirzi parameter and field in 4D, N=1 supergravity

    NASA Astrophysics Data System (ADS)

    Gates, S. James, Jr.; Ketov, Sergei V.; Yunes, Nicolás

    2009-09-01

    We embed the loop quantum gravity Barbero-Immirzi parameter and field within an action describing 4D, N=1 supergravity and thus within a low-energy effective action of superstring/M theory. We use the fully gauge-covariant description of supergravity in (curved) superspace. The gravitational constant is replaced with the vacuum expectation value of a scalar field, which in local supersymmetry is promoted to a complex, covariantly chiral scalar superfield. The imaginary part of this superfield couples to a supersymmetric Holst term. The Holst term also serves as a starting point in the loop quantum gravity action. This suggest the possibility of a relation between loop quantum gravity and supersymmetric string theory, where the Barbero-Immirzi parameter and field of the former play the role of the supersymmetric axion in the latter. Adding matter fermions in loop quantum gravity may require the extension of the Holst action through the Nieh-Yan topological invariant, while in pure, matter-free supergravity their supersymmetric extensions are the same. We show that, when the Barbero-Immirzi parameter is promoted to a field in the context of 4D supergravity, it is equivalent to adding a dynamical complex chiral (dilaton-axion) superfield with a nontrivial kinetic term (or Kähler potential), coupled to supergravity.

  11. Bimanual coupling effects during arm immobilization and passive movements.

    PubMed

    Garbarini, Francesca; Rabuffetti, Marco; Piedimonte, Alessandro; Solito, Gianluca; Berti, Anna

    2015-06-01

    When humans simultaneously perform different movements with both hands, each limb movement interferes with the contralateral limb movement (bimanual coupling). Previous studies on both healthy volunteers and patients with central or peripheral nervous lesions suggested that such motor constraints are tightly linked to intentional motor programs, rather than to movement execution. Here, we aim to investigate this phenomenon, by using a circles-lines task in which, when subjects simultaneously draw lines with the right hand and circles with the left hand, both the trajectories tend to become ovals (bimanual coupling effect). In a first group, we immobilized the subjects' left arm with a cast and asked them to try to perform the bimanual task. In a second group, we passively moved the subjects' left arm and asked them to perform voluntary movements with their right arm only. If the bimanual coupling arises from motor intention and planning rather than spatial movements, we would expect different results in the two groups. In the Blocked group, where motor intentionality was required but movements in space were prevented by immobilization of the arm, a significant coupling effect (i.e., a significant increase of the ovalization index for the right hand lines) was found. On the contrary, in the Passive group, where movements in space were present but motor intentionality was not required, no significant coupling effect was observed. Our results confirmed, in healthy subjects, the central role of the intentional and predictive operations, already evidenced in pathological conditions, for the occurrence of bimanual coupling.

  12. Effect of capacitive coupling in a miniature inductively coupled plasma source

    SciTech Connect

    Takao, Yoshinori; Eriguchi, Koji; Ono, Kouichi

    2012-11-01

    Two-dimensional axisymmetric particle-in-cell simulations with a Monte Carlo collision algorithm (PIC-MCC) have been conducted to investigate the effect of capacitive coupling in a miniature inductively coupled plasma source (mICP) by using two models: an inductive model and a hybrid model. The mICP is 3 mm in radius and 6 mm in height with a three-turn planar coil, where argon plasma is sustained. In the inductive model, the coil is assumed to be electrostatically shielded, and thus the discharge is purely inductive coupling. In the hybrid model, we assume that the different turns of the coil act like electrodes in capacitive discharge to include the effect of capacitive coupling. The voltage applied to these electrodes decreases linearly from the powered end of the coil towards the grounded end. The numerical analysis has been performed for rf frequencies in the range of 100-1000 MHz, and the power absorbed by the plasma in the range of 5-50 mW at a fixed pressure of 500 mTorr. The PIC-MCC results show that potential oscillations at the plasma-dielectric interface are not negligible, and thus the major component of the absorbed power is caused by the axial motion of electrons in the hybrid model, although almost all of the power absorption is due to the azimuthal motion of electrons in the inductive model. The effect of capacitive coupling is more significant at lower rf frequencies and at higher absorbed powers under the calculation conditions examined. Moreover, much less coil currents are required in the hybrid model.

  13. Digit ratio (2D:4D), lateral preferences, and performance in fencing.

    PubMed

    Voracek, Martin; Reimer, Barbara; Ertl, Clara; Dressler, Stefan G

    2006-10-01

    The second to fourth digit ratio (2D:4D) is a sexually dimorphic trait (men tend to have lower values than women) and a likely biomarker for the organizational (permanent) effects of prenatal androgens on the human brain and body. Prenatal testosterone, as reflected by 2D:4D, has many extragenital effects, including its relevance for the formation of an efficient cardiovascular system. Previous research, reviewed here, has therefore investigated possible associations of 2D:4D with sport performance. Several studies found more masculinized digit ratio patterns (low 2D:4D values or a negative right-minus-left difference in 2D:4D) to be related to high performance in running, soccer, and skiing. The present research tested this hypothesis in a sample of 54 tournament fencers, predominantly from Austria. For men, negative right-left differences in 2D:4D corresponded significantly to better current as well as highest national fencing rankings, independent of training intensity and fencing experience. The mean 2D:4D values of these fencers were significantly lower and the proportion of left-handers was elevated relative to the local general population. For the right hand, the ratio was somewhat lower in male sabre fencers than in male epée and foil fencers combined and significantly lower in left-handed compared to right-handed fencers. Although nonsignificant due to low statistical power, effect sizes suggested that crossed versus congruent hand-eye and hand-foot preferences might also be related to fencing performance. The present findings add to the evidence that 2D:4D might be a performance indicator for men across a variety of sports.

  14. Phonon coupling effects in proton scattering from Ca40

    NASA Astrophysics Data System (ADS)

    Mackintosh, R. S.; Keeley, N.

    2014-10-01

    Background: Formal optical model theory shows that coupling to vibrational nuclear states generates a nonlocal and l-dependent dynamical polarization potential (DPP). Little is established concerning the DPP, yet its properties are crucial for explaining the departures of optical model potentials (OMPs) from global behavior and for the rigorous extraction of spectroscopic information from direct reactions. Purpose: To appraise the application of channel coupling followed by S-matrix inversion for the systematic exploration of the contribution of the coupling of collective states to the nucleon OMP and to identify properties of nuclear potentials indicative of l-dependence. Methods: S-matrix to potential, Slj→V(r )+l .sVSO(r), inversion provides local potentials that precisely reproduce the elastic channel S-matrix from coupled channel (CC) calculations. Subtracting the elastic channel uncoupled (bare) potential yields a local and l-independent representation of the DPP. The dependence of this local DPP upon the nature of the coupled states and upon other parameters can be studied. Results: All components of the DPP arising from coupling to vibrational states are substantially undulatory with a point-by-point magnitude therefore disproportionate to their contribution to volume integrals. Information relating to dynamical nonlocality is found. The proton charge leads to a substantial difference between DPPs for protons and neutrons. Conclusions: Undulatory features in potentials found in precision fits to elastic scattering data are significant, are a consequence of coupling to inelastic channels and must be allowed for in phenomenology; they are indirect evidence of l-dependence. Within the model, coupling to excited states magnifies the effect of the proton charge on the difference between proton-nucleus and neutron-nucleus interactions. Coupled channel plus inversion is a procedure of wide applicability, complementary to evaluation of the Feshbach formalism.

  15. Hadza hunter-gatherer men do not have more masculine digit ratios (2D:4D).

    PubMed

    Apicella, Coren L; Tobolsky, Victoria A; Marlowe, Frank W; Miller, Kathleen W

    2016-02-01

    The ratio between the length of the second and the length of the fourth digit (2D:4D) is sexually dimorphic such that males of many species possess a lower ratio than females, particularly in the right hand. Still, men and women often exhibit overlapping 2D:4D ranges and the ratio is highly variable between populations. In order to further explore populational variability, we chose to analyze 2D:4D in the Hadza, a population of hunter-gatherers living in Tanzania. Data were collected separately by two researchers over the course of three years (1998, 2001, 2006) from 152 adult participants (male: n = 76, female: n = 76). Independent samples t-tests were used to explore sex differences, paired samples t-tests were used to explore directional effects within each sex, and linear regression and one-way ANOVA were used to test possible age effects. In none of the years, or pooled (n = 152), did we find evidence that adult men have a lower 2D:4D than adult women. If anything, the data suggest that women in this population have a significantly lower right hand 2D:4D than men (P < 0.001, d = 0.57). In contrast, left hand 2D:4D did not exhibit a sex difference (P = 0.862, d = 0.03). These findings challenge the current view that lower 2D:4D in men is a uniform characteristic of our species. Cross-populational variance in 2D:4D may be related to known patterns of hormonal variation resulting from both genetic and environmental mechanisms, though this relationship merits further investigation. © 2015 Wiley Periodicals, Inc.

  16. A 4D representation of DNA sequences and its application

    NASA Astrophysics Data System (ADS)

    Liao, Bo; Tan, Mingshu; Ding, Kequan

    2005-02-01

    A 4D representation of DNA sequences has been derived for mathematical denotation of DNA sequence. The 4D representation also avoids loss of information accompanying alternative 2D and 3D representation. The geometrical centers of the 4D graph of DNA sequences indicate the distribution of base frequencies. A interesting phenomenon is observed for Goat and Gallus β-globin genomes with high G + C content. The examination of similarities/dissimilarities among the coding sequences of the first exon of β-globin gene of different species illustrates the utility of the approach.

  17. Effect of Coriolis coupling in chemical reaction dynamics.

    PubMed

    Chu, Tian-Shu; Han, Ke-Li

    2008-05-14

    It is essential to evaluate the role of Coriolis coupling effect in molecular reaction dynamics. Here we consider Coriolis coupling effect in quantum reactive scattering calculations in the context of both adiabaticity and nonadiabaticity, with particular emphasis on examining the role of Coriolis coupling effect in reaction dynamics of triatomic molecular systems. We present the results of our own calculations by the time-dependent quantum wave packet approach for H + D2 and F(2P3/2,2P1/2) + H2 as well as for the ion-molecule collisions of He + H2 +, D(-) + H2, H(-) + D2, and D+ + H2, after reviewing in detail other related research efforts on this issue.

  18. SU-D-BRB-01: 4D-CT Lung Ventilation Images Vary with 4D-CT Sorting Techniques.

    PubMed

    Yamamoto, T; Kabus, S; Lorenz, C; Johnston, E; Maxim, P; Loo, B; Keall, P

    2012-06-01

    4D-CT ventilation imaging is a novel promising technique for lung functional imaging and has potential as a biomarker for radiation pneumonitis, but has not been validated in human subjects. The current 4D- CT technique with phase-based sorting results in artifacts at an alarmingly high frequency (90%), which may introduce variations into ventilation calculations. The purpose of this study was to quantify the variability of 4D- CT ventilation imaging to 4D-CT sorting techniques. Two 4D-CT images were generated from the same data set by: (1) phase-based; (2) anatomic similarity- and abdominal displacement-based sorting for five patients. Two ventilation image sets (V_phase and V_anat) were then calculated by deformable image registration of peak-exhale and peak-inhale4D-CT images and quantification of regional volume change based on Hounsfield unit change. The variability of 4D-CT ventilation imaging wasquantified using the voxel-based Spearman rank correlation coefficients and Dice similarity coefficients (DSC) for the spatial overlap of segmented low- functional lung regions. The relationship between the abdominal motionrange variation and ventilation variation was also assessed using linearregression. Furthermore, the correlations between V_phase or V_anat and SPECT ventilation images (assumed ground-truth) were compared. In general, displacement- and anatomic similarity-based sorting reduced 4D- CT artifacts compared to phase-based sorting. The voxel-based correlationsbetween V_phase and V_anat were only moderate (range, 0.57-0.77). The DSCs for the low-functional lung regions were moderate to substantial (0.58-0.70). The relationship between the motion range variation and ventilation variation was strong on average (R2=0.79±0.25), suggesting that ventilation variations are related to 4D-CT artifacts. Vanat was found to improve correlations with SPECT ventilation images compared to V_phase. 4D-CT ventilation images vary markedly with 4D-CT sorting techniques. 4

  19. Beyond the rainbow: Effects from pion back-coupling

    SciTech Connect

    Fischer, Christian S.; Williams, Richard

    2008-10-01

    We investigate hadronic unquenching effects in light quarks and mesons. To this end, we take into account the back-coupling of the pion onto the quark propagator within the nonperturbative continuum framework of Schwinger-Dyson equations (SDE) and Bethe-Salpeter equations (BSE). We improve on a previous approach by explicitly solving both the coupled system of SDEs and BSEs in the complex plane and the normalization problem for Bethe-Salpeter kernels depending on the total momentum of the meson. As a result of our study, we find considerable unquenching effects in the spectrum of light pseudoscalar, vector and axial-vector mesons.

  20. Effects of boson dispersion in fermion-boson coupled systems

    NASA Astrophysics Data System (ADS)

    Motome, Yukitoshi; Kotliar, Gabriel

    2000-11-01

    We study the nonlinear feedback in a fermion-boson system using an extension of dynamical mean-field theory and the quantum Monte Carlo method. In the perturbative regimes (weak-coupling and atomic limits) the effective interaction among fermions increases as the width of the boson dispersion increases. In the strong-coupling regime away from the antiadiabatic limit, the effective interaction decreases as we increase the width of the boson dispersion. This behavior is closely related to complete softening of the boson field. We elucidate the parameters that control this nonperturbative region where fluctuations of the dispersive bosons enhance the delocalization of fermions.

  1. Effects of relationship education on couple communication and satisfaction: A randomized controlled trial with low-income couples.

    PubMed

    Williamson, Hannah C; Altman, Noemi; Hsueh, JoAnn; Bradbury, Thomas N

    2016-02-01

    Although preventive educational interventions for couples have been examined in more than 100 experimental studies, the value of this work is limited by reliance on economically advantaged populations and by an absence of data on proposed mediators and moderators. Data from the Supporting Healthy Marriage Project-a randomized, controlled trial of relationship education for couples living with low incomes-were therefore analyzed to test whether intervention effects on relationship satisfaction would be mediated by observational assessments of relationship communication and whether any such effects would be moderated by couples' pretreatment risk. Within the larger sample of Supporting Healthy Marriage Project couples randomized to a relationship education or no-treatment control condition, the present analyses focus on the 1,034 couples who provided (a) data on sociodemographic risk at baseline, (b) observational data on couple communication 12 months after randomization, and (c) reports of relationship satisfaction 30 months after randomization. Intervention couples reported higher satisfaction at 30 months than control couples, regardless of their level of pretreatment risk. Among higher risk couples, the intervention improved observed communication as well. Contrary to prediction, treatment effects on satisfaction were not mediated by improvements in communication, and improvements in communication did not translate into greater satisfaction. Relationship education programs produce small improvements in relationship satisfaction and communication, particularly for couples at elevated sociodemographic risk. The absence of behavioral effects on satisfaction indicates, however, that the mechanisms by which couples may benefit from relationship education are not yet well understood. (c) 2016 APA, all rights reserved).

  2. 4d Photoionization of Free Singly Charged Xenon Ions

    NASA Astrophysics Data System (ADS)

    Gottwald, A.; Gerth, Ch.; Richter, M.

    1999-03-01

    Electron spectroscopy in direct 4d photoionization of free Xe+ ions has been realized for the first time, applying various timing and coincidence techniques to suppress and to monitor on line the strong fluctuating background. The ionization energies of 4d5/2 and 4d3/2 electrons of Xe+\\(5p5 2P3/2\\) and Xe+\\(5p5 2P1/2\\) were determined and compared to calculated RHF(CI) values and to corresponding results of neutral Xe\\(5p6 1S0\\) atoms to study the influence of the outer-shell electron occupation on the 4d-1 inner-shell process.

  3. Potent inhibition of HIV-1 entry by (s4dU)35.

    PubMed

    Horváth, András; Tokés, Szilvia; Hartman, Tracy; Watson, Karen; Turpin, Jim A; Buckheit, Robert W; Sebestyén, Zsolt; Szöllosi, János; Benko, Ilona; Bardos, Thomas J; Dunn, Joseph A; Fésüs, László; Tóth, Ferenc D; Aradi, Janos

    2005-04-10

    We have previously reported the potent in vitro HIV-1 anti-reverse transcriptase activity of a 35-mer of 4-thio-deoxyuridylate [(s(4)dU)(35)]. In efforts to define its activity in a more physiological system, studies were carried out to determine the stage of viral infection that this compound mediates its anti-viral effect. Results of the studies reported herein show that (s(4)dU)(35) is nontoxic and is capable of inhibiting both single and multi-drug resistant HIV strains (IC(50): 0.8-25.4 microg/ml) in vitro. Besides its previously reported anti-RT activity, (s(4)dU)(35) mediated its antiviral action by preventing virus attachment (IC(50): 0.002-0.003 microg/ml), and was stable in vitro and slowly degraded by DNAses. Competition studies and fluorescence resonance energy transfer (FRET) experiments indicated that (s(4)dU)(35) preferentially binds to CD4 receptors, but not to CD48. Confocal laser scanning microscopy (CLSM) studies showed that (s(4)dU)(35) did not penetrate into the cells and colocalized with cell surface thioredoxin. Our studies identify (s(4)dU)(35) as a potential novel HIV entry inhibitor that may have utility as either a systemic antiretroviral or as a preventing agent for HIV transmission.

  4. Finger length ratio (2D:4D) and dimensions of sexual orientation.

    PubMed

    Kraemer, Bernd; Noll, Thomas; Delsignore, Aba; Milos, Gabriella; Schnyder, Ulrich; Hepp, Urs

    2006-01-01

    It has been suggested that both adult sexual orientation and the 2nd to 4th finger length ratio (2D:4D) are influenced by prenatal testosterone levels. Bearing this in mind, 2D:4D has been tested as a proxy measure of the putative prenatal testosterone impact on adult human homosexuality, but the results are inconsistent. To date, most studies in this field of research comprise categorical group comparison of heterosexuals and homosexuals with respect to their 2D:4D. The purpose of our study was to evaluate 2D:4D and the dimensional perspective of sexual orientation in addition to categorical results. We examined a community-based sample of 409 subjects and calculated correlations of 2D:4D and sexual orientation as a continuum ranging from homosexual to heterosexual. We found a significant negative correlation of 2D:4D with homosexual orientation (fantasy, attraction, activity and general score) in women, but not in men. Our results indicate that with higher prenatal testosterone levels in women, the likelihood of homosexual orientation might increase. We hypothesize a continuous neurohormonal sexual differentiation of the brain, most notably for women, that overrides categories and results in varying dimensions of sexual orientation. This hypothesis contrasts with the predominant suggestion of fixed organizational effects of androgens in the brain and a categorical sexual orientation.

  5. Planning 4D intensity-modulated arc therapy for tumor tracking with a multileaf collimator

    NASA Astrophysics Data System (ADS)

    Niu, Ying; Betzel, Gregory T.; Yang, Xiaocheng; Gui, Minzhi; Parke, William C.; Yi, Byongyong; Yu, Cedric X.

    2017-02-01

    This study introduces a practical four-dimensional (4D) planning scheme of IMAT using 4D computed tomography (4D CT) for planning tumor tracking with dynamic multileaf beam collimation. We assume that patients can breathe regularly, i.e. the same way as during 4D CT with an unchanged period and amplitude, and that the start of 4D-IMAT delivery can be synchronized with a designated respiratory phase. Each control point of the IMAT-delivery process can be associated with an image set of 4D CT at a specified respiratory phase. Target is contoured at each respiratory phase without a motion-induced margin. A 3D-IMAT plan is first optimized on a reference-phase image set of 4D CT. Then, based on the projections of the planning target volume in the beam’s eye view at different respiratory phases, a 4D-IMAT plan is generated by transforming the segments of the optimized 3D plan by using a direct aperture deformation method. Compensation for both translational and deformable tumor motion is accomplished, and the smooth delivery of the transformed plan is ensured by forcing connectivity between adjacent angles (control points). It is envisioned that the resultant plans can be delivered accurately using the dose rate regulated tracking method which handles breathing irregularities (Yi et al 2008 Med. Phys. 35 3955–62).This planning process is straightforward and only adds a small step to current clinical 3D planning practice. Our 4D planning scheme was tested on three cases to evaluate dosimetric benefits. The created 4D-IMAT plans showed similar dose distributions as compared with the 3D-IMAT plans on a single static phase, indicating that our method is capable of eliminating the dosimetric effects of breathing induced target motion. Compared to the 3D-IMAT plans with large treatment margins encompassing respiratory motion, our 4D-IMAT plans reduced radiation doses to surrounding normal organs and tissues.

  6. Association of C4d deposition with clinical outcomes in IgA nephropathy.

    PubMed

    Espinosa, Mario; Ortega, Rosa; Sánchez, Marina; Segarra, Alfons; Salcedo, Maria Teresa; González, Fayna; Camacho, Rafael; Valdivia, Miguel Angel; Cabrera, Rocio; López, Katia; Pinedo, Fernando; Gutierrez, Eduardo; Valera, Alfonso; Leon, Miryam; Cobo, Maria Angeles; Rodriguez, Rosa; Ballarín, Jose; Arce, Yolanda; García, Beatriz; Muñoz, María Dolores; Praga, Manuel

    2014-05-01

    Several studies have suggested that activation of the complement system is a contributing pathogenic mechanism in IgA nephropathy (IgAN). C4d staining is an inexpensive and easy-to-perform method for the analysis of renal biopsies. This study aimed to assess the clinical and prognostic implications of C4d staining in IgAN. This retrospective cohort study included 283 patients with IgAN in 11 hospitals in Spain who underwent a renal biopsy between 1979 and 2010. The primary predictor was mesangial C4d staining. Secondary predictors included demographic, clinical, and laboratory characteristics, and Oxford pathologic classification criteria. The primary end point was the cumulative percentage of patients who developed ESRD, defined as onset of chronic dialysis or renal transplantation. C4d was analyzed by immunohistochemical staining using a polyclonal antibody. Kaplan-Meier and Cox proportional hazards analyses were performed to evaluate the effect of C4d staining on renal survival. There were 109 patients (38.5%) and 174 patients (61.5%) who were classified as C4d positive and C4d negative, respectively. Renal survival at 20 years was 28% in C4d-positive patients versus 85% in C4d-negative patients (P<0.001). Independent risk factors associated with ESRD were as follows: proteinuria (hazard ratio [HR] per every 1 g/d increase. 1.16; 95% confidence interval [95% CI], 1.03 to 1.31; P=0.01), eGFR (HR per every 1 ml/min per 1.73 m(2) increase, 0.96; 95% CI, 0.94 to 0.97; P<0.001), T2 Oxford classification (tubular atrophy/interstitial fibrosis, >50%; HR, 4.42; 95% CI, 1.40 to 13.88; P=0.01), and C4d-positive staining (HR, 2.45; 95% CI, 1.30 to 4.64; P=0.01). C4d-positive staining is an independent risk factor for the development of ESRD in IgAN. This finding is consistent with the possibility that complement activation is involved in the pathogenesis of this disease.

  7. 4d N =2 theories with disconnected gauge groups

    NASA Astrophysics Data System (ADS)

    Argyres, Philip C.; Martone, Mario

    2017-03-01

    In this paper we present a beautifully consistent web of evidence for the existence of interacting 4d rank-1 N = 2 SCFTs obtained from gauging discrete subgroups of global symmetries of other existing 4d rank-1 N = 2 SCFTs. The global symmetries that can be gauged involve a non-trivial combination of discrete subgroups of the U(1) R , low-energy EM duality group SL(2,Z), and the outer automorphism group of the flavor symmetry algebra, Out( F ).

  8. Respiratory motion correction in 4D-PET by simultaneous motion estimation and image reconstruction (SMEIR)

    NASA Astrophysics Data System (ADS)

    Kalantari, Faraz; Li, Tianfang; Jin, Mingwu; Wang, Jing

    2016-08-01

    In conventional 4D positron emission tomography (4D-PET), images from different frames are reconstructed individually and aligned by registration methods. Two issues that arise with this approach are as follows: (1) the reconstruction algorithms do not make full use of projection statistics; and (2) the registration between noisy images can result in poor alignment. In this study, we investigated the use of simultaneous motion estimation and image reconstruction (SMEIR) methods for motion estimation/correction in 4D-PET. A modified ordered-subset expectation maximization algorithm coupled with total variation minimization (OSEM-TV) was used to obtain a primary motion-compensated PET (pmc-PET) from all projection data, using Demons derived deformation vector fields (DVFs) as initial motion vectors. A motion model update was performed to obtain an optimal set of DVFs in the pmc-PET and other phases, by matching the forward projection of the deformed pmc-PET with measured projections from other phases. The OSEM-TV image reconstruction was repeated using updated DVFs, and new DVFs were estimated based on updated images. A 4D-XCAT phantom with typical FDG biodistribution was generated to evaluate the performance of the SMEIR algorithm in lung and liver tumors with different contrasts and different diameters (10-40 mm). The image quality of the 4D-PET was greatly improved by the SMEIR algorithm. When all projections were used to reconstruct 3D-PET without motion compensation, motion blurring artifacts were present, leading up to 150% tumor size overestimation and significant quantitative errors, including 50% underestimation of tumor contrast and 59% underestimation of tumor uptake. Errors were reduced to less than 10% in most images by using the SMEIR algorithm, showing its potential in motion estimation/correction in 4D-PET.

  9. Substitutional 4d and 5d impurities in graphene.

    PubMed

    Alonso-Lanza, Tomás; Ayuela, Andrés; Aguilera-Granja, Faustino

    2016-08-21

    We describe the structural and electronic properties of graphene doped with substitutional impurities of 4d and 5d transition metals. The adsorption energies and distances for 4d and 5d metals in graphene show similar trends for the later groups in the periodic table, which are also well-known characteristics of 3d elements. However, along earlier groups the 4d impurities in graphene show very similar adsorption energies, distances and magnetic moments to the 5d ones, which can be related to the influence of the 4d and 5d lanthanide contraction. Surprisingly, within the manganese group, the total magnetic moment of 3 μB for manganese is reduced to 1 μB for technetium and rhenium. We find that compared with 3d elements, the larger size of the 4d and 5d elements causes a high degree of hybridization with the neighbouring carbon atoms, reducing spin splitting in the d levels. It seems that the magnetic adjustment of graphene could be significantly different if 4d or 5d impurities are used instead of 3d impurities.

  10. [2D:4D finger ratio and language development].

    PubMed

    Albores-Gallo, L; Fernández-Guasti, A; Hernández-Guzmán, L; List-Hilton, C

    A possible hormonal influence in language development has been suggested in the recent years. The 2D:4D finger ratio is an indirect measure for prenatal androgen exposure. It is negatively related to prenatal testosterone and positively related to prenatal estrogen, resulting in a lower ratio for men and a larger ratio for women. It can be explored in children as young as 2 years old. To study if an association exists between the 2D:4D finger ratio and language development (vocabulary) and/or language problems. The lengths of the second digit (index finger) (2D) and the fourth digit (ring finger) (4D) were measured in 97 preschoolers and the Language Development Survey was administered to the parents. A weak negative correlation between language development (vocabulary) and right 2D:4D ratio was found in both sexes for children aged 4 or less years, significant only in boys. A strong negative correlation between language articulation problems and right 2D:4D ratio in both sexes for children aged 3 or less years, and a lower negative correlation between articulation problems and right 2D:4D ratio were found for boys aged 4 or less years. Findings suggest an important role for testosterone in language development (vocabulary) and a possible influence on articulation problems, probably through higher testosterone levels.

  11. Combining C(4) D and MS as a dual detection approach for capillary electrophoresis.

    PubMed

    Beutner, Andrea; Cunha, Rafael Rodrigues; Richter, Eduardo Mathias; Matysik, Frank-Michael

    2016-04-01

    The hyphenation of two detectors in combination with separation techniques is a powerful tool to enhance the analytical information. In this work, we present for the first time the coupling of two important detectors for capillary electrophoresis (CE), namely capacitively coupled contactless conductivity detection (C(4) D) and electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS). The elaborated experimental protocol took into account the requirements of separation aspects and the compatibility with both detectors. ESI-TOF-MS requires background electrolytes (BGE) containing only volatile components such as ammonium acetate or formate. These, however, exhibit a rather high conductivity, which is disadvantageous for C(4) D. Thus, the selection of the BGE in an appropriate concentration was undertaken for the determination of various phenolic compounds serving as a model system. The chosen BGE was a 10 mM ammonium acetate/ammonia buffer with a pH of 9. This BGE was a compromise concerning the detection performance of both detectors. The LODs for m-cresol, m- and p-nitrophenol, and 2,4-dinitrophenol were 3.1 μM (C(4) D), 0.8 μM (MS), 0.8 μM (MS), and 1.5 μM (MS), respectively. Moreover, the overall separation efficiency was excellent illustrating that detector-induced band broadening can be neglected in the CE-C(4) D/MS system. The analytical characteristics for the determination of phenolic compounds show the suitability of this dual detection approach and demonstrate the complementary use of C(4) D and MS detection.

  12. Extracting Effective Higgs Couplings in the Golden Channel

    DOE PAGES

    Chen, Yi; Vega-Morales, Roberto

    2014-04-08

    Kinematic distributions in Higgs decays to four charged leptons, the so called ‘golden channel, are a powerful probe of the tensor structure of its couplings to neutral electroweak gauge bosons. In this study we construct the first part of a comprehensive analysis framework designed to maximize the information contained in this channel in order to perform direct extraction of the various possible Higgs couplings. We first complete an earlier analytic calculation of the leading order fully differential cross sections for the golden channel signal and background to include the 4e and 4μ final states with interference between identical final states.more » We also examine the relative fractions of the different possible combinations of scalar-tensor couplings by integrating the fully differential cross section over all kinematic variables as well as show various doubly differential spectra for both the signal and background. From these analytic expressions we then construct a ‘generator level’ analysis framework based on the maximum likelihood method. Then, we demonstrate the ability of our framework to perform multi-parameter extractions of all the possible effective couplings of a spin-0 scalar to pairs of neutral electroweak gauge bosons including any correlations. Furthermore, this framework provides a powerful method for study of these couplings and can be readily adapted to include the relevant detector and systematic effects which we demonstrate in an accompanying study to follow.« less

  13. Extracting Effective Higgs Couplings in the Golden Channel

    SciTech Connect

    Chen, Yi; Vega-Morales, Roberto

    2014-04-08

    Kinematic distributions in Higgs decays to four charged leptons, the so called ‘golden channel, are a powerful probe of the tensor structure of its couplings to neutral electroweak gauge bosons. In this study we construct the first part of a comprehensive analysis framework designed to maximize the information contained in this channel in order to perform direct extraction of the various possible Higgs couplings. We first complete an earlier analytic calculation of the leading order fully differential cross sections for the golden channel signal and background to include the 4e and 4μ final states with interference between identical final states. We also examine the relative fractions of the different possible combinations of scalar-tensor couplings by integrating the fully differential cross section over all kinematic variables as well as show various doubly differential spectra for both the signal and background. From these analytic expressions we then construct a ‘generator level’ analysis framework based on the maximum likelihood method. Then, we demonstrate the ability of our framework to perform multi-parameter extractions of all the possible effective couplings of a spin-0 scalar to pairs of neutral electroweak gauge bosons including any correlations. Furthermore, this framework provides a powerful method for study of these couplings and can be readily adapted to include the relevant detector and systematic effects which we demonstrate in an accompanying study to follow.

  14. Factors Influencing Dislodgeable 2, 4-D Plant Residues from Hybrid Bermudagrass (Cynodon dactylon L. x C. transvaalensis) Athletic Fields

    PubMed Central

    Ahmed, Khalied A.; Breeden, Gregory K.

    2016-01-01

    Research to date has confirmed 2,4-D residues may dislodge from turfgrass; however, experiments have not been conducted on hybrid bermudagrass (Cynodon dactylon L. x C. transvaalensis), the most common athletic field turfgrass in subtropical climates. More specifically, previous research has not investigated the effect of post-application irrigation on dislodgeable 2,4-D residues from hybrid bermudagrass and across turfgrass species, research has been nondescript regarding sample time within a d (TWD) or conducted in the afternoon when the turfgrass canopy is dry, possibly underestimating potential for dislodgement. The effect of irrigation and TWD on 2,4-D dislodgeability was investigated. Dislodgeable 2,4-D amine was reduced > 300% following irrigation. From 2 to 7 d after treatment (DAT), ≤ 0.5% of applied 2,4-D was dislodged from irrigated turfgrass, while ≤ 2.3% of applied 2,4-D was dislodged when not irrigated. 2,4-D dislodgeability decreased as TWD increased. Dislodgeable 2,4-D residues declined to < 0.1% of the applied at 1 DAT– 13:00, and increased to 1 to 3% of the applied 2 DAT– 5:00, suggesting 2,4-D re-suspended on treated turfgrass vegetation overnight. In conclusion, irrigating treated turfgrass reduced dislodgeable 2,4-D. 2,4-D dislodgeability increased as TWD decreased, which was attributed to non-precipitation climatic conditions favoring turfgrass canopy wetness. This research will improve turfgrass management practices and research designed to minimize human 2,4-D exposure. PMID:26863005

  15. Visco-elastic effects in strongly coupled dusty plasmas

    SciTech Connect

    Bandyopadhyay, P.; Prasad, G.; Sen, A.; Kaw, P. K.

    2008-09-07

    We report on experimental evidence of visco-elastic effects in a strongly coupled dusty plasma through investigations of the propagation characteristics of low frequency dust acoustic waves and by excitations of transverse shear waves in a DC discharge Argon plasma.

  16. Effects of ionizing radiation on charge-coupled imagers

    NASA Technical Reports Server (NTRS)

    Killiany, J. M.; Baker, W. D.; Saks, N. S.; Barbe, D. F.

    1975-01-01

    The effects of ionizing radiation on three different charge coupled imagers have been investigated. Device performance was evaluated as a function of total gamma ray dose. The principal failure mechanisms have been identified for each particular device structure. The clock and bias voltages required for high total dose operation of the devices are presented.

  17. 4D-Fingerprint Categorical QSAR Models for Skin Sensitization Based on Classification Local Lymph Node Assay Measures

    PubMed Central

    Li, Yi; Tseng, Yufeng J.; Pan, Dahua; Liu, Jianzhong; Kern, Petra S.; Gerberick, G. Frank; Hopfinger, Anton J.

    2008-01-01

    Currently, the only validated methods to identify skin sensitization effects are in vivo models, such as the Local Lymph Node Assay (LLNA) and guinea pig studies. There is a tremendous need, in particular due to novel legislation, to develop animal alternatives, eg. Quantitative Structure-Activity Relationship (QSAR) models. Here, QSAR models for skin sensitization using LLNA data have been constructed. The descriptors used to generate these models are derived from the 4D-molecular similarity paradigm and are referred to as universal 4D-fingerprints. A training set of 132 structurally diverse compounds and a test set of 15 structurally diverse compounds were used in this study. The statistical methodologies used to build the models are logistic regression (LR), and partial least square coupled logistic regression (PLS-LR), which prove to be effective tools for studying skin sensitization measures expressed in the two categorical terms of sensitizer and non-sensitizer. QSAR models with low values of the Hosmer-Lemeshow goodness-of-fit statistic, χHL2, are significant and predictive. For the training set, the cross-validated prediction accuracy of the logistic regression models ranges from 77.3% to 78.0%, while that of PLS-logistic regression models ranges from 87.1% to 89.4%. For the test set, the prediction accuracy of logistic regression models ranges from 80.0%-86.7%, while that of PLS-logistic regression models ranges from 73.3%-80.0%. The QSAR models are made up of 4D-fingerprints related to aromatic atoms, hydrogen bond acceptors and negatively partially charged atoms. PMID:17226934

  18. Parallel Infrastructure Modeling and Inversion Module for E4D

    SciTech Connect

    2014-10-09

    Electrical resistivity tomography ERT is a method of imaging the electrical conductivity of the subsurface. Electrical conductivity is a useful metric for understanding the subsurface because it is governed by geomechanical and geochemical properties that drive subsurface systems. ERT works by injecting current into the subsurface across a pair of electrodes, and measuring the corresponding electrical potential response across another pair of electrodes. Many such measurements are strategically taken across an array of electrodes to produce an ERT data set. These data are then processed through a computationally demanding process known as inversion to produce an image of the subsurface conductivity structure that gave rise to the measurements. Data can be inverted to provide 2D images, 3D images, or in the case of time-lapse 3D imaging, 4D images. ERT is generally not well suited for environments with buried electrically conductive infrastructure such as pipes, tanks, or well casings, because these features tend to dominate and degrade ERT images. This reduces or eliminates the utility of ERT imaging where it would otherwise be highly useful for, for example, imaging fluid migration from leaking pipes, imaging soil contamination beneath leaking subusurface tanks, and monitoring contaminant migration in locations with dense network of metal cased monitoring wells. The location and dimension of buried metallic infrastructure is often known. If so, then the effects of the infrastructure can be explicitly modeled within the ERT imaging algorithm, and thereby removed from the corresponding ERT image. However,there are a number of obstacles limiting this application. 1) Metallic infrastructure cannot be accurately modeled with standard codes because of the large contrast in conductivity between the metal and host material. 2) Modeling infrastructure in true dimension requires the computational mesh to be highly refined near the metal inclusions, which increases

  19. Coupling liquids acoustic velocity effects on elastic metallic bioglass properties

    NASA Astrophysics Data System (ADS)

    Metiri, W.; Hadjoub, F.; Doghmane, A.; Hadjoub, Z.

    2009-11-01

    The effect of surface acoustic wave, SAW, velocities of coupling liquids on acoustical properties of several bulk metallic glasses, BMG, has been investigated using simulation program based on acoustic microscopy. Thus, we determined variations of critical angles at which the excitation of longitudinal mode, θL and Rayleigh mode, θR occurs as a function of wave velocities in different coupling liquids, Vliq. Linear relations of the form θi =ai0 +βiVliq were deduced. The importance of such formula, used with Snell's law, lies in the direct determination of SAW velocities and consequently mechanical properties of BMGs.

  20. Digit ratio (2D:4D) and postoperative pain perception.

    PubMed

    Kasielska-Trojan, Anna; Stabryła, Piotr; Antoszewski, Bogusław

    2017-07-01

    It has not been established whether sex differences in pain perception are influenced by prenatal sex hormones. Digit ratio as an indicator of prenatal hormone exposure can be used as a simple measure of the influence of prenatal hormones on pain sensitivity or perception in adulthood. The aim of this study was to determine a correlation between the 2D:4D ratio and pain perception in the postoperative period after rhinoplasty. A prospective cohort study of 100 patients (50 women of the mean age of 30.74±8.09years and 50 men of the mean age of 30.98±10.86years) who underwent posttraumatic rhinoplasty due to the nose trauma in Plastic, Reconstructive and Aesthetic Surgery Clinic. The following measurements were taken the day before a surgery: body height, waist and hip circumference, II and IV digits' lengths and body weight. All subjects filled in a questionnaire including 0-10-point VAS scales to assess postoperative pain 1h after an operation (AO), 6h AO, 12h AO, 24h AO and 48h AO. Women with low 2D:4D reported significantly more pain 1h after an operation than women with high 2D:4D. Similar correlation was observed for low 2D:4D in women 48h AO. In men, low 2D:4D was associated with lower postoperative pain 12h AO (p=0.029). In conclusion, we showed that low 2D:4D in women was associated with high postoperative pain, and low right 2D:4D in men was associated with low postoperative pain. This may suggest that intrauterine estrogen exposure makes women more resistant to pain. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Soil matrix and macropore biodegradation of 2,4-D

    SciTech Connect

    Pivetz, B.E.; Steenhuis, T.S.

    1995-07-01

    Preferential flow of pesticides in macropores can lead to decreased travel times through the vadose zone and increased groundwater contamination. Macropores, however, may present a favorable environment for biodegradation because of greater oxygen, nutrient, and substrate supply, and higher microbial populations in earthworm burrows, compared to the soil matrix. The biodegradation of 2,4-dichlorophenoxyacetic acid (2,4-D) was measured in macropores and soil matrix of packed soil columns (7.0-cm diam., 10-cm length) and undisturbed cores contained as well-defined artificial macropore and the undisturbed cores contained earthworm-burrow macropores. A 50 {mu}g/L 2,4-D solution was continuously applied to the unsaturated soil surface and breakthrough curves (BTCs) indicating pesticide loss in the effluent were obtained from the soil matrix and macropore flow paths. Biodegradation rates were calculated separately for each flow path by comparing the BTCs to BTCs representing abiotic conditions, and dividing the 2,4-D loss by the travel time through each flow path. The biodegradation rates increased with time in both flow paths, and the final biodegradation rate in the macropore region surpassed that of the matrix, presumably because of increased microbial populations in the macropore. Complete loss of the 2,4-D in both flow paths was observed after continuous application of 2,4-D for 400 h, with maximum column-averaged 2,4-D loss rates of 0.879 {mu}g/(L h) in the matrix and 1.073 {mu}g/(L h) in the macropore. Biodegradation of 2,4-D was also observed in the macropore and matrix regions of the undisturbed soil cores. 19 refs., 7 figs., 2 tabs.

  2. Vacuum polarization corrections to low energy quark effective couplings

    NASA Astrophysics Data System (ADS)

    Paulo, Ademar; Braghin, Fabio L.

    2014-07-01

    In this work corrections to low energy punctual effective quark couplings up to the eighth order are calculated by considering vacuum polarization effects with the scalar quark-antiquark condensate. The departing point is a QCD-based Nambu-Jona-Lasinio model. By separating the quark field into two components, one that condenses and another one for interacting quarks, the former is integrated out with the help of usual auxiliary fields and an effective action in terms of interacting quark fields is found. The scalar auxiliary field reduces to the quark-antiquark condensate in the vacuum and the determinant is expanded in powers of the quark-antiquark bilinears generating chiral invariant effective 2N-quark interactions (N =2,3…). The corresponding coupling constants and effective masses are estimated, and the general trend is that for increasing the effective gluon mass the values of the effective coupling constants decrease. All the values are in good agreement with phenomenological fits.

  3. Infrasound propagation modelling using 4d atmospheric backgrounds

    NASA Astrophysics Data System (ADS)

    Streicher, Florian; Wuest, Sabine; Bittner, Michael

    2014-05-01

    Infrasound is very low frequency sound. Because of its low attenuation in the atmosphere, it is able to travel up to thousands of kilometers around the globe. A sound wave may cover a distance of about 1.000km within an hour. Sensors monitoring infrasound however can be some thousands of kilometers away from a specific source. For determining an infrasonic event, e.g. by the use of propagation modelling, with growing distance it is increasingly important to consider changes of the atmosphere in space and time. Most important and always accounted for in propagation modelling are changes of the atmosphere in vertical direction. Changes in horizontal direction generally are much smaller and sometimes are left away, e.g. for short distance calculations. Finally, changes in time hardly are considered. Effect and potential benefit of the use of 4d atmospheric specifications in infrasound propagation modelling are compared to 1d and 3d backgrounds, also taking into account selected atmospheric conditions and weather events. Differences in propagation on short and long distances are discussed. The results are based on HARPA/DLR.

  4. Dynamical Coupled-channels Effects on Pion Photoproduction

    SciTech Connect

    Julia-Diaz, B; Lee, T -S. H.; Matsuyama, A; Sato, T; Smith, L C

    2007-12-18

    The electromagnetic pion production reactions are investigated within the dynamical coupled-channels model developed in {\\bf Physics Reports, 439, 193 (2007)}. The meson-baryon channels included in this study are $\\gamma N$, $\\pi N$, $\\eta N$, and the $\\pi\\Delta$, $\\rho N$ and $\\sigma N$ resonant components of the $\\pi\\pi N$ channel. With the hadronic parameters of the model determined in a recent study of $\\pi N$ scattering, we show that the pion photoproduction data up to the second resonance region can be described to a very large extent by only adjusting the bare $\\gamma N \\rightarrow N^*$ helicity amplitudes, while the non-resonant electromagnetic couplings are taken from previous works. It is found that the coupled-channels effects can contribute about 10 - 20 $\\%$ of the production cross sections in the $\\Delta$ (1232) resonance region, and can drastically change the magnitude and shape of the cross sections in the second resonance region. The importance of the off-shell effects in a dynamical approach is also demonstrated. The meson cloud effects as well as the coupled-channels contributions to the $\\gamma N \\rightarrow N^*$ form factors are found to be mainly in the low $Q^2$ region. For the magnetic M1 $\\gamma N \\rightarrow \\Delta$ (1232) form factor, the results are close to that of the Sato-Lee Model. Necessary improvements to the model and future developments are discussed.

  5. Cotunneling Drag Effect in Coulomb-Coupled Quantum Dots

    NASA Astrophysics Data System (ADS)

    Keller, A. J.; Lim, J. S.; Sánchez, David; López, Rosa; Amasha, S.; Katine, J. A.; Shtrikman, Hadas; Goldhaber-Gordon, D.

    2016-08-01

    In Coulomb drag, a current flowing in one conductor can induce a voltage across an adjacent conductor via the Coulomb interaction. The mechanisms yielding drag effects are not always understood, even though drag effects are sufficiently general to be seen in many low-dimensional systems. In this Letter, we observe Coulomb drag in a Coulomb-coupled double quantum dot and, through both experimental and theoretical arguments, identify cotunneling as essential to obtaining a correct qualitative understanding of the drag behavior.

  6. Sema4d is required for the development of the hindbrain boundary and skeletal muscle in zebrafish

    SciTech Connect

    Yang, Jie; Zeng, Zhen; Wei, Juncheng; Jiang, Lijun; Ma, Quanfu; Wu, Mingfu; Huang, Xiaoyuan; Ye, Shuangmei; Li, Ye; Ma, Ding; Gao, Qinglei

    2013-04-05

    Highlights: ► Sema4d was expressed at all developmental stages of zebrafish. ► Knockdown of sema4d in embryos resulted in defects in the hindbrain and the trunk structure. ► Knockdown of sema4d in embryos upregulated the expression of three hindbrain rhombomere markers. ► Knockdown of sema4d in embryos increased the expression of myogenic regulatory factors. ► Knockdown of sema4d in embryos resulted in an obvious increase of cell apoptosis. -- Abstract: Semaphorin4d (SEMA4D), also known as CD100, an oligodendrocyte secreted R-Ras GTPase-activating protein (GAP), affecting axonal growth is involved in a range of processes including cell adhesion, motility, angiogenesis, immune responses and tumour progression. However, its actual physiological mechanisms and its role in development remain unclear. This study has focused on the role of sema4d in the development and expression patterns in zebrafish embryos and the effect of its suppression on development using sema4d-specific antisense morpholino-oligonucleotides. In this study the knockdown of sema4d, expressed at all developmental stages, lead to defects in the hindbrain and trunk structure of zebrafish embryos. In addition, these phenotypes appeared to be associated with the abnormal expression of three hindbrain rhombomere boundary markers, wnt1, epha4a and foxb1.2, and two myogenic regulatory factors, myod and myog. Further, a notable increase of cell apoptosis appeared in the sema4d knockdown embryos, while no obvious reduction in cell proliferation was observed. Collectively, these data suggest that sema4d plays an important role in the development of the hindbrain and skeletal muscle.

  7. Directional sinogram interpolation for motion weighted 4D cone-beam CT reconstruction

    NASA Astrophysics Data System (ADS)

    Zhang, Hua; Kruis, Matthijs; Sonke, Jan-Jakob

    2017-03-01

    The image quality of respiratory sorted four-dimensional (4D) cone-beam (CB) computed tomography (CT) is often limited by streak artifacts due to insufficient projections. A motion weighted reconstruction (MWR) method is proposed to decrease streak artifacts and improve image quality. Firstly, respiratory correlated CBCT projections were interpolated by directional sinogram interpolation (DSI) to generate additional CB projections for each phase and subsequently reconstructed. Secondly, local motion was estimated by deformable image registration of the interpolated 4D CBCT. Thirdly, a regular 3D FDK CBCT was reconstructed from the non-interpolated projections. Finally, weights were assigned to each voxel, based on the local motion, and then were used to combine the 3D FDK CBCT and interpolated 4D CBCT to generate the final 4D image. MWR method was compared with regular 4D CBCT scans as well as McKinnon and Bates (MKB) based reconstructions. Comparisons were made in terms of (1) comparing the steepness of an extracted profile from the boundary of the region-of-interest (ROI), (2) contrast-to-noise ratio (CNR) inside certain ROIs, and (3) the root-mean-square-error (RMSE) between the planning CT and CBCT inside a homogeneous moving region. Comparisons were made for both a phantom and four patient scans. In a 4D phantom, RMSE were reduced by 24.7% and 38.7% for MKB and MWR respectively, compared to conventional 4D CBCT. Meanwhile, interpolation induced blur was minimal in static regions for MWR based reconstructions. In regions with considerable respiratory motion, image blur using MWR is less than the MKB and 3D Feldkamp (FDK) methods. In the lung cancer patients, average CNRs of MKB, DSI and MWR improved by a factor 1.7, 2.8 and 3.5 respectively relative to 4D FDK. MWR effectively reduces RMSE in 4D cone-beam CT and improves the image quality in both the static and respiratory moving regions compared to 4D FDK and MKB methods.

  8. The Effectiveness of Emotionally Focused Couples Therapy on Sexual Satisfaction and Marital Adjustment of Infertile Couples with Marital Conflicts.

    PubMed

    Soleimani, Ali Akbar; Najafi, Maryam; Ahmadi, Khodabakhsh; Javidi, Nasirudin; Hoseini Kamkar, Elnaz; Mahboubi, Mohamad

    2015-01-01

    The purpose of this investigation is to determine the efficacy of emotionally focused couples therapy (EFT-C) on enhancement of marital adjustment in infertile couples. This was a semi-experimental study with a pre- and post-test design. We selected 30 infertile couples (60 subjects) by purposive sampling. Couples were randomly assigned to two groups, sample and control. Each group consisted of 15 couples who had marital maladjustment and low sexual satisfaction. Couples answered the marital adjustment and sexual satisfaction questionnaires at baseline after which the sample group received 10 sessions of EFT-C. Results of pre-test and post-test showed that EFT-C significantly impacted marital adjustment and sexual satisfaction. EFT-C had a significant effect on enhancement of satisfaction, cohesion and affectional expression. This approach impacted physical and emotional sexual satisfaction of infertile couples.

  9. The Effectiveness of Emotionally Focused Couples Therapy on Sexual Satisfaction and Marital Adjustment of Infertile Couples with Marital Conflicts

    PubMed Central

    Soleimani, Ali Akbar; Najafi, Maryam; Ahmadi, Khodabakhsh; Javidi, Nasirudin; Hoseini Kamkar, Elnaz; Mahboubi, Mohamad

    2015-01-01

    Background The purpose of this investigation is to determine the efficacy of emotionally focused couples therapy (EFT-C) on enhancement of marital adjustment in infertile couples. Materials and Methods This was a semi-experimental study with a pre- and post-test design. We selected 30 infertile couples (60 subjects) by purposive sampling. Couples were randomly assigned to two groups, sample and control. Each group consisted of 15 couples who had marital maladjustment and low sexual satisfaction. Couples answered the marital adjustment and sexual satisfaction questionnaires at baseline after which the sample group received 10 sessions of EFT-C. Results Results of pre-test and post-test showed that EFT-C significantly impacted marital adjustment and sexual satisfaction. Conclusion EFT-C had a significant effect on enhancement of satisfaction, cohesion and affectional expression. This approach impacted physical and emotional sexual satisfaction of infertile couples. PMID:26644864

  10. Understanding the Electronic Structure of 4d Metal Complexes: From Molecular Spinors to L-Edge Spectra of a di-Ru Catalyst

    SciTech Connect

    Alperovich, Igor; Smolentsev, Grigory; Moonshiram, Dooshaye; Jurss, Jonah W.; Concepcion, Javier J.; Meyer, Thomas J.; Soldatov, Alexander; Pushkar, Yulia

    2015-09-17

    L{sub 2,3}-edge X-ray absorption spectroscopy (XAS) has demonstrated unique capabilities for the analysis of the electronic structure of di-Ru complexes such as the blue dimer cis,cis-[Ru{sub 2}{sup III}O(H{sub 2}O){sub 2}(bpy){sub 4}]{sup 4+} water oxidation catalyst. Spectra of the blue dimer and the monomeric [Ru(NH{sub 3}){sub 6}]{sup 3+} model complex show considerably different splitting of the Ru L{sub 2,3} absorption edge, which reflects changes in the relative energies of the Ru 4d orbitals caused by hybridization with a bridging ligand and spin-orbit coupling effects. To aid the interpretation of spectroscopic data, we developed a new approach, which computes L{sub 2,3}-edges XAS spectra as dipole transitions between molecular spinors of 4d transition metal complexes. This allows for careful inclusion of the spin-orbit coupling effects and the hybridization of the Ru 4d and ligand orbitals. The obtained theoretical Ru L{sub 2,3}-edge spectra are in close agreement with experiment. Critically, existing single-electron methods (FEFF, FDMNES) broadly used to simulate XAS could not reproduce the experimental Ru L-edge spectra for the [Ru(NH{sub 3}){sub 6}]{sup 3+} model complex nor for the blue dimer, while charge transfer multiplet (CTM) calculations were not applicable due to the complexity and low symmetry of the blue dimer water oxidation catalyst. We demonstrated that L-edge spectroscopy is informative for analysis of bridging metal complexes. The developed computational approach enhances L-edge spectroscopy as a tool for analysis of the electronic structures of complexes, materials, catalysts, and reactive intermediates with 4d transition metals.

  11. Density functional investigation of metal-metal interactions in d4d4 face-shared [M2Cl9]3 - (M = Mn, Tc, Re) systems.

    PubMed

    Cavigliasso, Germán; Stranger, Robert

    2004-04-05

    The molecular and electronic structures of the d(4)d(4) face-shared [M(2)Cl(9)](3)(-) (M = Mn, Tc, Re) dimers have been calculated by density functional methods in order to investigate metal-metal bonding in this series. The electronic structures of these systems have been analyzed using potential energy curves for the broken-symmetry and other spin states arising from the various d(4)d(4) coupling modes, and closed energy cycles have been utilized to identify and quantify the parameters which are most important in determining the preference for electron localization or delocalization and for high-spin or low-spin configurations. In [Tc(2)Cl(9)](3)(-) and [Re(2)Cl(9)](3)(-), the global minimum has been found to be a spin-triplet state arising from the coupling of metal centers with low-spin configurations, and characterized by delocalization of the metal-based electrons in a double (sigma and delta(pi)) bond with a metal-metal separation of 2.57 A. In contrast, high-spin configurations and electron localization are favored in [Mn(2)Cl(9)](3)(-), the global minimum for this species being the ferromagnetic S = 4 state with a rather long metal-metal separation of 3.43 A. These results are consistent with metal-metal overlap and ligand-field effects prevailing over spin polarization effects in the Tc and Re systems, but with the opposite trend being observed in the Mn complex. The ground states and metal-metal bonding observed for the d(4)d(4) systems in this study parallel those previously found for the analogous d(2)d(2) complexes of V, Nb, and Ta, and can be rationalized on the basis that the d(4)d(4) dimer configuration is the hole equivalent of the d(2)d(2) configuration.

  12. True 4D Image Denoising on the GPU

    PubMed Central

    Eklund, Anders; Andersson, Mats; Knutsson, Hans

    2011-01-01

    The use of image denoising techniques is an important part of many medical imaging applications. One common application is to improve the image quality of low-dose (noisy) computed tomography (CT) data. While 3D image denoising previously has been applied to several volumes independently, there has not been much work done on true 4D image denoising, where the algorithm considers several volumes at the same time. The problem with 4D image denoising, compared to 2D and 3D denoising, is that the computational complexity increases exponentially. In this paper we describe a novel algorithm for true 4D image denoising, based on local adaptive filtering, and how to implement it on the graphics processing unit (GPU). The algorithm was applied to a 4D CT heart dataset of the resolution 512  × 512  × 445  × 20. The result is that the GPU can complete the denoising in about 25 minutes if spatial filtering is used and in about 8 minutes if FFT-based filtering is used. The CPU implementation requires several days of processing time for spatial filtering and about 50 minutes for FFT-based filtering. The short processing time increases the clinical value of true 4D image denoising significantly. PMID:21977020

  13. True 4D Image Denoising on the GPU.

    PubMed

    Eklund, Anders; Andersson, Mats; Knutsson, Hans

    2011-01-01

    The use of image denoising techniques is an important part of many medical imaging applications. One common application is to improve the image quality of low-dose (noisy) computed tomography (CT) data. While 3D image denoising previously has been applied to several volumes independently, there has not been much work done on true 4D image denoising, where the algorithm considers several volumes at the same time. The problem with 4D image denoising, compared to 2D and 3D denoising, is that the computational complexity increases exponentially. In this paper we describe a novel algorithm for true 4D image denoising, based on local adaptive filtering, and how to implement it on the graphics processing unit (GPU). The algorithm was applied to a 4D CT heart dataset of the resolution 512  × 512  × 445  × 20. The result is that the GPU can complete the denoising in about 25 minutes if spatial filtering is used and in about 8 minutes if FFT-based filtering is used. The CPU implementation requires several days of processing time for spatial filtering and about 50 minutes for FFT-based filtering. The short processing time increases the clinical value of true 4D image denoising significantly.

  14. Closed system of coupling effects in generalized thermo-elastoplasticity

    NASA Astrophysics Data System (ADS)

    Śloderbach, Z.

    2016-05-01

    In this paper, the field equations of the generalized coupled thermoplasticity theory are derived using the postulates of classical thermodynamics of irreversible processses. Using the Legendre transformations two new thermodynamics potentials P and S depending upon internal thermodynamic forces Π are introduced. The most general form for all the thermodynamics potentials are assumed instead of the usually used additive form. Due to this assumption, it is possible to describe all the effects of thermomechanical couples and also the elastic-plastic coupling effects observed in such materials as rocks, soils, concretes and in some metalic materials. In this paper not only the usual postulate of existence of a dissipation qupotential (the Gyarmati postulate) is used to derive the velocity equation. The plastic flow constitutive equations have the character of non-associated flow laws even when the Gyarmati postulate is assumed. In general formulation, the plastic strain rate tensor is normal to the surface of the generalized function of plastic flow defined in the the space of internal thermodynamic forces Π but is not normal to the yield surface. However, in general formulation and after the use the Gyarmati postulate, the direction of the sum of the plastic strain rate tensor and the coupled elastic strain rate tensor is normal to the yield surface.

  15. Effect of proton transfer on the electronic coupling in DNA

    NASA Astrophysics Data System (ADS)

    Rak, Janusz; Makowska, Joanna; Voityuk, Alexander A.

    2006-06-01

    The effects of single and double proton transfer within Watson-Crick base pairs on donor-acceptor electronic couplings, Vda, in DNA are studied on the bases of quantum chemical calculations. Four dimers [AT,AT], [GC,GC], [GC,AT] and [GC,TA)] are considered. Three techniques - the generalized Mulliken-Hush scheme, the fragment charge method and the diabatic states method - are employed to estimate Vda for hole transfer between base pairs. We show that both single- and double proton transfer (PT) reactions may substantially affect the electronic coupling in DNA. The electronic coupling in [AT,AT] is predicted to be most sensitive to PT. Single PT within the first base pair in the dimer leads to increase in the hole transfer efficiency by a factor of 4, while proton transfer within the second pair should substantially, by 2.7 times, decrease the rate of charge transfer. Thus, directional asymmetry of the PT effects on the electronic coupling is predicted. The changes in the Vda matrix elements correlate with the topological properties of orbitals of donor and acceptor and can be qualitatively rationalized in terms of resonance structures of donor and acceptor. Atomic pair contributions to the Vda matrix elements are also analyzed.

  16. Using 2D: 4D digit ratios to determine motor skills in children.

    PubMed

    Wang, Y; Wang, H-L; Li, Y-H; Zhu, F-L; Li, S-J; Ni, H

    2016-03-01

    In past few decades, there has an outburst of research surrounding second to fourth finger digit ratio (2D:4D) and its relation to prenatal sex steroids including both testosterone and estrogen. In utero, testosterone and estrogen are responsible for the differences in digit ratio between the genders. Recent research has tried to extend past the influence of steroids and look at the potential effect of digit ratios on fine and gross motor skills in children. We compiled the current understanding of the connection between sex hormones and the development of the 2D:4D ratio as well as the effect the ratio has on motor skills. There seems to be a significant positive correlation between 2D:4D digit ratio and precision of fine motor skill. In addition, there is a negative correlation between 2D:4D ratio and speed of fine motor activity. In this review, we will outline the use of 2D:4D ratio as a biomarker for prenatal sex steroids and through that, a proxy marker for fine and gross motor skills.

  17. Finger length ratio (2D:4D) in adults with gender identity disorder.

    PubMed

    Kraemer, Bernd; Noll, Thomas; Delsignore, Aba; Milos, Gabriella; Schnyder, Ulrich; Hepp, Urs

    2009-06-01

    From early childhood, gender identity and the 2nd to 4th finger length ratio (2D:4D) are discriminative characteristics between sexes. Both the human brain and 2D:4D may be influenced by prenatal testosterone levels. This calls for an examination of 2D:4D in patients with gender identity disorder (GID) to study the possible influence of prenatal testosterone on gender identity. Until now, the only study carried out on this issue suggests lower prenatal testosterone levels in right-handed male-to-female GID patients (MtF). We compared 2D:4D of 56 GID patients (39 MtF; 17 female-to-male GID patients, FtM) with data from a control sample of 176 men and 190 women. Bivariate group comparisons showed that right hand 2D:4D in MtF was significantly higher (feminized) than in male controls, but similar to female controls. The comparison of 2D:4D ratios of biological women revealed significantly higher (feminized) values for right hands of right handed FtM. Analysis of variance confirmed significant effects for sex and for gender identity on 2D:4D ratios but not for sexual orientation or for the interaction among variables. Our results indirectly point to the possibility of a weak influence of reduced prenatal testosterone as an etiological factor in the multifactorially influenced development of MtF GID. The development of FtM GID seems even more unlikely to be notably influenced by prenatal testosterone.

  18. Is maternal periconceptional smoking associated with 2D:4D digit ratio in their children?

    PubMed

    Velez, M P; Arbuckle, T E; Monnier, P; Fraser, W D

    2017-05-23

    The 2nd--4th finger ratio (2D:4D) has been proposed as a potential indicator of greater androgen exposure during fetal development. Maternal periconceptional smoking may alter the homeostasis of fetal androgens, which could in turn result in differential development of 2D:4Ds in utero. The aim of the present study was to assess the effect of maternal periconceptional smoking (i.e. 1 year before through the first trimester of pregnancy) on the 2D:4D of children within The Maternal-Infant Research on Environmental Chemicals (MIREC) study. Maternal smoking history was obtained through questionnaires during the first trimester of pregnancy in 2001 women from 10 cities across Canada. The periconceptional smoking prevalence was 12%. A follow-up study was conducted to measure growth and development up to 5 years of age in a subsample of some 800 MIREC children (MIREC-CD Plus), and digital pictures of the ventral surface of both hands were obtained in mothers and children (2-5 years). The 2D:4D was calculated as the ratio of the 2nd and 4th fingers of each hand. Boys had lower mean 2D:4Ds compared with girls in both hands. Age and maternal 2D:4D were strong determinants of the children's 2D:4D, however, the mean 2D:4D did not differ among children whose mothers had smoked during the periconceptional period compared with those who had not, irrespective of sex. In conclusion, we did not find an association between maternal periconceptional smoking and children's 2D:4D, although the smoking prevalence was low.

  19. Electromechanical coupling in piezoelectric nanobeams due to the flexoelectric effect

    NASA Astrophysics Data System (ADS)

    Zhou, Z. D.; Yang, C. P.; Su, Y. X.; Huang, R.; Lin, X. L.

    2017-09-01

    The flexoelectric effect is a coupling of polarization and strain gradient, which exists in a wide variety of materials and may lead to strong size-dependent properties at the nanoscale. Based on an extension to the classical beam model, this paper investigates the electromechanical coupling response of piezoelectric nanobeams with different electrical boundary conditions including the effect of flexoelectricity. The electric Gibbs free energy and the variational principle are used to derive the governing equations with three types of electrical boundary conditions. Closed-form solutions are obtained for static bending of cantilever beams. The results show that the normalized effective stiffness increases with decreasing beam thickness in the open circuit electrical boundary conditions with or without surface electrodes. The induced electric potential due to the flexoelectric effect is obtained under the open circuit conditions, which may be important for sensing or energy harvesting applications. An intrinsic thickness depending on the material properties is identified for the maximum induced electric potential. The present results also show that flexoelectricity has a more significant effect on the electroelastic responses than piezoelectricity at the nanoscale. Our analysis in the present study can be useful for understanding of the electromechanical coupling in nanobeams with flexoelectricity.

  20. Interaction of 2,4-dichlorophenoxyacetic acid (2,4-D) with cell and model membranes.

    PubMed

    Suwalsky, M; Benites, M; Villena, F; Aguilar, F; Sotomayor, C P

    1996-12-04

    2,4-dichlorophenoxyacetic acid (2,4-D), a widely used herbicide, is a component of the "agent orange' whose toxicity has been extensively studied without definite conclusions. In order to evaluate its perturbing effect upon cell membranes, 2,4-D was made to interact with human erythrocytes and molecular models. These studies were performed by scanning electron microscopy on red cells, fluorescence spectroscopy on dimyristoylphosphatidylcholine (DMPC) large unilamellar vesicles and X-ray diffraction on multilayers of DMPC and dimyristoylphosphatidylethanolamine (DMPE). It was observed that 2,4-D induced a pronounced shape change to the erythrocytes. This effect is explained by the herbicide interaction with the outer monolayer of the red cell membrane.

  1. Bootstrapping mixed correlators in 4D N = 1 SCFTs

    NASA Astrophysics Data System (ADS)

    Li, Daliang; Meltzer, David; Stergiou, Andreas

    2017-07-01

    The numerical conformal bootstrap is used to study mixed correlators in N = 1 superconformal field theories (SCFTs) in d = 4 spacetime dimensions. Systems of fourpoint functions involving scalar chiral and real operators are analyzed, including the case where the scalar real operator is the zero component of a global conserved current multiplet. New results on superconformal blocks as well as universal constraints on the space of 4D N = 1 SCFTs with chiral operators are presented. At the level of precision used, the conditions under which the putative "minimal" 4D N = 1 SCFT may be isolated into a disconnected allowed region remain elusive. Nevertheless, new features of the bounds are found that provide further evidence for the presence of a special solution to crossing symmetry corresponding to the "minimal" 4D N = 1 SCFT.

  2. 2D:4D Ratio and its Implications in Medicine.

    PubMed

    Jeevanandam, Saravanakumar; Muthu, Prathibha K

    2016-12-01

    Digit ratios, especially 2D:4D ratio, a potential proxy marker for prenatal androgen exposure shows sexual dimorphism. Existing literature and recent research show accumulating evidence on 2D:4D ratio showing correlations with various phenotypic traits in humans. Ratio of 2D:4D is found to correlate negatively to testosterone and positively to oestrogen in the foetus. Interestingly, it is constant since birth and not influenced by the adult hormone levels. Usually, males have lower ratios when compared to females. Prenatal androgen exposure and therefore, digit ratios have been reported to be associated with numerical competencies, spatial skills, handedness, cognitive abilities, academic performance, sperm counts, personalities and prevalence of obesity, migraine, eating disorders, depression, myopia, autism etc. The authors have attempted to write a brief account on the digit ratios and the dimorphism observed in various physiological, psychological and behavioural traits. Also, the authors have discussed the relevant molecular basics and the methods of measurement of digit ratios.

  3. High resolution 4D HPCH experiment for sequential assignment of (13)C-labeled RNAs via phosphodiester backbone.

    PubMed

    Saxena, Saurabh; Stanek, Jan; Cevec, Mirko; Plavec, Janez; Koźmiński, Wiktor

    2015-11-01

    The three-dimensional structure determination of RNAs by NMR spectroscopy requires sequential resonance assignment, often hampered by assignment ambiguities and limited dispersion of (1)H and (13)C chemical shifts, especially of C4'/H4'. Here we present a novel through-bond 4D HPCH NMR experiment involving phosphate backbone where C4'-H4' correlations are resolved along the (1)H3'-(31)P spectral planes. The experiment provides high peak resolution and effectively removes ambiguities encountered during assignments. Enhanced peak dispersion is provided by the inclusion of additional (31)P and (1)H3' dimensions and constant-time evolution of chemical shifts. High spectral resolution is obtained by using non-uniform sampling in three indirect dimensions. The experiment fully utilizes the isotopic (13)C-labeling with evolution of C4' carbons. Band selective (13)C inversion pulses are used to achieve selectivity and prevent signal dephasing due to the C4'-C3' and C4'-C5' homonuclear couplings. Multiple quantum line narrowing is employed to minimize sensitivity loses. The 4D HPCH experiment is verified and successfully applied to a non-coding 34-nt RNA consisting typical structure elements and a 14-nt RNA hairpin capped by cUUCGg tetraloop.

  4. 4D cone beam CT via spatiotemporal tensor framelet

    SciTech Connect

    Gao, Hao; Li, Ruijiang; Xing, Lei; Lin, Yuting

    2012-11-15

    Purpose: On-board 4D cone beam CT (4DCBCT) offers respiratory phase-resolved volumetric imaging, and improves the accuracy of target localization in image guided radiation therapy. However, the clinical utility of this technique has been greatly impeded by its degraded image quality, prolonged imaging time, and increased imaging dose. The purpose of this letter is to develop a novel iterative 4DCBCT reconstruction method for improved image quality, increased imaging speed, and reduced imaging dose. Methods: The essence of this work is to introduce the spatiotemporal tensor framelet (STF), a high-dimensional tensor generalization of the 1D framelet for 4DCBCT, to effectively take into account of highly correlated and redundant features of the patient anatomy during respiration, in a multilevel fashion with multibasis sparsifying transform. The STF-based algorithm is implemented on a GPU platform for improved computational efficiency. To evaluate the method, 4DCBCT full-fan scans were acquired within 30 s, with a gantry rotation of 200°; STF is also compared with a state-of-art reconstruction method via spatiotemporal total variation regularization. Results: Both the simulation and experimental results demonstrate that STF-based reconstruction achieved superior image quality. The reconstruction of 20 respiratory phases took less than 10 min on an NVIDIA Tesla C2070 GPU card. The STF codes are available at https://sites.google.com/site/spatiotemporaltensorframelet . Conclusions: By effectively utilizing the spatiotemporal coherence of the patient anatomy among different respiratory phases in a multilevel fashion with multibasis sparsifying transform, the proposed STF method potentially enables fast and low-dose 4DCBCT with improved image quality.

  5. Digit Ratio (2D:4D): A Biomarker for Prenatal Sex Steroids and Adult Sex Steroids in Challenge Situations

    PubMed Central

    Manning, John; Kilduff, Liam; Cook, Christian; Crewther, Blair; Fink, Bernhard

    2013-01-01

    Digit ratio (2D:4D) denotes the relative length of the second and fourth digits. This ratio is considered to be a biomarker of the balance between fetal testosterone (T) and estrogen (E) in a narrow window of early ontogeny. Evidence for this assertion is derived from direct and indirect measures of prenatal hormonal exposure (in experimental animals, via amniotic fluid samples and in the study of sex-typical traits) in relation to 2D:4D. In contrast, the relationships between 2D:4D and levels of sex steroids in adults are less clear, as many correlational studies of 2D:4D and adult sex steroids have concluded that this association is statistically non-significant. Here, we suggest that in order to understand the link between 2D:4D and sex hormones, one must consider both fetal organizing and adult activating effects of T and E. In particular, we hypothesize that 2D:4D correlates with organizing effects on the endocrine system that moderate activating effects in adulthood. We argue that this is particularly evident in “challenging” conditions such as aggressive and sexual encounters, in which individuals show increased levels of T. We discuss this refinement of the 2D:4D paradigm in relation to the links between 2D:4D and sports performance, and aggression. PMID:24523714

  6. Digit Ratio (2D:4D): A Biomarker for Prenatal Sex Steroids and Adult Sex Steroids in Challenge Situations.

    PubMed

    Manning, John; Kilduff, Liam; Cook, Christian; Crewther, Blair; Fink, Bernhard

    2014-01-01

    Digit ratio (2D:4D) denotes the relative length of the second and fourth digits. This ratio is considered to be a biomarker of the balance between fetal testosterone (T) and estrogen (E) in a narrow window of early ontogeny. Evidence for this assertion is derived from direct and indirect measures of prenatal hormonal exposure (in experimental animals, via amniotic fluid samples and in the study of sex-typical traits) in relation to 2D:4D. In contrast, the relationships between 2D:4D and levels of sex steroids in adults are less clear, as many correlational studies of 2D:4D and adult sex steroids have concluded that this association is statistically non-significant. Here, we suggest that in order to understand the link between 2D:4D and sex hormones, one must consider both fetal organizing and adult activating effects of T and E. In particular, we hypothesize that 2D:4D correlates with organizing effects on the endocrine system that moderate activating effects in adulthood. We argue that this is particularly evident in "challenging" conditions such as aggressive and sexual encounters, in which individuals show increased levels of T. We discuss this refinement of the 2D:4D paradigm in relation to the links between 2D:4D and sports performance, and aggression.

  7. 4D ultrasound imaging - ethically justifiable in India?

    PubMed

    Indiran, Venkatraman

    2017-01-01

    Four-dimensional (4D) ultrasound (real-time volume sonography), which has been used in the West since the last decade for the determination of gender as well as for bonding and entertainment of the parents, has become widely available in India in this decade. Here, I would like to discuss the ethical issues associated with 4D ultrasonography in India. These are self-referral, the use of the technology for non-medical indications, a higher possibility of the disclosure of the foetus' gender and safety concerns.

  8. Emerging Applications of Abdominal 4D Flow MRI

    PubMed Central

    Roldán-Alzate, Alejandro; Francois, Christopher J.; Wieben, Oliver; Reeder, Scott B.

    2016-01-01

    OBJECTIVE Comprehensive assessment of abdominal hemodynamics is crucial for many clinical diagnoses but is challenged by a tremendous complexity of anatomy, normal physiology, and a wide variety of pathologic abnormalities. This article introduces 4D flow MRI as a powerful technique for noninvasive assessment of the hemodynamics of abdominal vascular territories. CONCLUSION Four-dimensional flow MRI provides clinicians with a more extensive and straightforward approach to evaluate disorders that affect blood flow in the abdomen. This review presents a series of clinical cases to illustrate the utility of 4D flow MRI in the comprehensive assessment of the abdominal circulation. PMID:27187681

  9. The 4-D approach to visual control of autonomous systems

    NASA Technical Reports Server (NTRS)

    Dickmanns, Ernst D.

    1994-01-01

    Development of a 4-D approach to dynamic machine vision is described. Core elements of this method are spatio-temporal models oriented towards objects and laws of perspective projection in a foward mode. Integration of multi-sensory measurement data was achieved through spatio-temporal models as invariants for object recognition. Situation assessment and long term predictions were allowed through maintenance of a symbolic 4-D image of processes involving objects. Behavioral capabilities were easily realized by state feedback and feed-foward control.

  10. Prevention of alveolar bone loss in an osteoporotic animal model via interference of semaphorin 4d.

    PubMed

    Zhang, Y; Wei, L; Miron, R J; Zhang, Q; Bian, Z

    2014-11-01

    Semaphorin 4d (Sema4d) has been proposed as a novel target gene for the treatment of osteoporosis. Recently, we fabricated a site-specific bone-targeting system from polymeric nanoparticles that demonstrates an ability to prevent bone loss in an osteoporotic model by interfering with Sema4d gene expression using small interference RNA (siRNA) molecules. The aim of the present investigation was to determine the effects of this targeting system on the periodontium, an area of high bone turnover. We demonstrated, by single photon emission computed tomography, that intravenous injection of this molecule in ovariectomized Balb/C mice is able to target alveolar bone peaking 4 hr post-injection. We then compared, by histological analysis, the bone volume/total volume (BV/TV), alveolar bone height loss, immunohistochemical expression of Sema4d, and total number of osteoclasts in mandibular alveolar bone. Four treatment modalities were compared as follows: (1) sham-operated, (2) OVX-operated, (3) OVX+estrogen replacement therapy, and (4) OVX+siRNA-Sema4d animals. The results from the present study demonstrate that an osteoporotic condition significantly increases alveolar bone height loss, and that the therapeutic effects via bone-targeting systems featuring interference of Sema4d are able to partly counteract alveolar bone loss caused by osteoporosis. While the future therapeutic demand for the large number of patients suffering from osteoporosis faces many challenges, we demonstrate within the present study an effective drug-delivery moiety with anabolic effects on the bone remodeling cycle able to locate and target alveolar bone regeneration.

  11. Micellar effects on dediazoniation and on azo coupling reactions.

    PubMed

    Pazo-Llorente, Román; Rodriguez-Menacho, M A Carmen; González-Romero, Elisa; Bravo-Díaz, Carlos

    2002-04-01

    The effects of a sodium dodecyl sulfate, SDS, micellar solution on the coupling rates of two arenediazonium ions, ArN(2)(+), with the hydrophobic 1-naphthylamine, 1NA and N-(1-naphthyl) ethylenediamine, NED, coupling agents and with the hydrophilic Na salt of 2-naphthol-6-sulfonic acid, 2N6S, have been studied. First, we explored the micellar effects on the thermal decomposition of the arenediazonium ions. The observed rate constants are slightly depressed or increased, depending on the nature of ArN(2)(+), compared to those in pure water upon increasing [SDS]. Estimations of the corresponding association constant to the micelle indicate that a significant fraction of the arenediazonium ions are incorporated into the micelles even at low surfactant concentrations. The sulfonate group in 2N6S prevents its incorporation into the micellar aggregate due to the electrostatic barrier imposed by the micelles and, in consequence, the coupling reaction is inhibited. In contrast, when employing the naphthylamine derivatives, the observed rate constant increase rapidly up to a maximum at [SDS]effect exerted by the micelles. The results are discussed in terms of the distribution of reactants between the micellar and aqueous pseudophases, the micellar-induced shift in the pK(a) of the amines, and the concentration/dilution effect exerted by the micelles.

  12. Effect of Spin-Orbit Coupling to Interacting Ultracold Atoms

    NASA Astrophysics Data System (ADS)

    Cui, Xiaoling

    2013-05-01

    The recent realization of spin-orbit (SO) coupling in neutral atoms has opened up new directions to explore novel SO effects in a diversity of new physical settings. In this talk, I shall discuss two important effects of SO coupling to interacting ultracold atoms. First, the presence of SO coupling will inevitably induce mixed scatterings and interference between different partial-waves, and as a result it could significantly affect the validity of widely-used pseudo-potentials. Explicitly, the s-wave pseudo-potential alone is approximately valid under more stringent conditions, while the p-wave pseudo-potential alone can no longer be used even near p-wave resonance. These results indicate a fundamental change of short-range physics for interacting atoms in high orbits, due to destructive interference with lower ones. Second, the presence of SO coupling will induce exotic scattering between spin-1/2 bosons confined in a quasi-one-dimensional waveguide, and lead to a Tonks gas with unique properties that have not been unveiled before. Explicitly, SO coupling will break the magnetization conservation during the scattering process, and also induce a sequence of scattering resonances (or Tonks limit) simultaneously in all scattering channels. Unlike the usual Tonks gas of identical bosons, the Tonks gas here, with strong spin-orbit entanglement, exhibits rich textures in spin and density distributions. These features can be directly observed in current cold atom experiment. This work is supported by Tsinghua University Initiative Scientific Research Program and National Natural Science Foundation of China Grant No. 11104158.

  13. Density functional theory investigation of 3d, 4d, and 5d 13-atom metal clusters

    SciTech Connect

    Piotrowski, Mauricio J.; Piquini, Paulo; Da Silva, Juarez L. F.

    2010-04-15

    The knowledge of the atomic structure of clusters composed by few atoms is a basic prerequisite to obtain insights into the mechanisms that determine their chemical and physical properties as a function of diameter, shape, surface termination, as well as to understand the mechanism of bulk formation. Due to the wide use of metal systems in our modern life, the accurate determination of the properties of 3d, 4d, and 5d metal clusters poses a huge problem for nanoscience. In this work, we report a density functional theory study of the atomic structure, binding energies, effective coordination numbers, average bond lengths, and magnetic properties of the 3d, 4d, and 5d metal (30 elements) clusters containing 13 atoms, M{sub 13}. First, a set of lowest-energy local minimum structures (as supported by vibrational analysis) were obtained by combining high-temperature first-principles molecular-dynamics simulation, structure crossover, and the selection of five well-known M{sub 13} structures. Several new lower energy configurations were identified, e.g., Pd{sub 13}, W{sub 13}, Pt{sub 13}, etc., and previous known structures were confirmed by our calculations. Furthermore, the following trends were identified: (i) compact icosahedral-like forms at the beginning of each metal series, more opened structures such as hexagonal bilayerlike and double simple-cubic layers at the middle of each metal series, and structures with an increasing effective coordination number occur for large d states occupation. (ii) For Au{sub 13}, we found that spin-orbit coupling favors the three-dimensional (3D) structures, i.e., a 3D structure is about 0.10 eV lower in energy than the lowest energy known two-dimensional configuration. (iii) The magnetic exchange interactions play an important role for particular systems such as Fe, Cr, and Mn. (iv) The analysis of the binding energy and average bond lengths show a paraboliclike shape as a function of the occupation of the d states and hence

  14. Review of 2,4-dichlorophenoxyacetic acid (2,4-D) biomonitoring and epidemiology

    PubMed Central

    Burns, Carol J.; Swaen, Gerard M. H.

    2012-01-01

    A qualitative review of the epidemiological literature on the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) and health after 2001 is presented. In order to compare the exposure of the general population, bystanders and occupational groups, their urinary levels were also reviewed. In the general population, 2,4-D exposure is at or near the level of detection (LOD). Among individuals with indirect exposure, i.e. bystanders, the urinary 2,4-D levels were also very low except in individuals with opportunity for direct contact with the herbicide. Occupational exposure, where exposure was highest, was positively correlated with behaviors related to the mixing, loading and applying process and use of personal protection. Information from biomonitoring studies increases our understanding of the validity of the exposure estimates used in epidemiology studies. The 2,4-D epidemiology literature after 2001 is broad and includes studies of cancer, reproductive toxicity, genotoxicity, and neurotoxicity. In general, a few publications have reported statistically significant associations. However, most lack precision and the results are not replicated in other independent studies. In the context of biomonitoring, the epidemiology data give no convincing or consistent evidence for any chronic adverse effect of 2,4-D in humans. PMID:22876750

  15. Review of 2,4-dichlorophenoxyacetic acid (2,4-D) biomonitoring and epidemiology.

    PubMed

    Burns, Carol J; Swaen, Gerard M H

    2012-10-01

    A qualitative review of the epidemiological literature on the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) and health after 2001 is presented. In order to compare the exposure of the general population, bystanders and occupational groups, their urinary levels were also reviewed. In the general population, 2,4-D exposure is at or near the level of detection (LOD). Among individuals with indirect exposure, i.e. bystanders, the urinary 2,4-D levels were also very low except in individuals with opportunity for direct contact with the herbicide. Occupational exposure, where exposure was highest, was positively correlated with behaviors related to the mixing, loading and applying process and use of personal protection. Information from biomonitoring studies increases our understanding of the validity of the exposure estimates used in epidemiology studies. The 2,4-D epidemiology literature after 2001 is broad and includes studies of cancer, reproductive toxicity, genotoxicity, and neurotoxicity. In general, a few publications have reported statistically significant associations. However, most lack precision and the results are not replicated in other independent studies. In the context of biomonitoring, the epidemiology data give no convincing or consistent evidence for any chronic adverse effect of 2,4-D in humans.

  16. The epidemic dynamics of hepatitis C virus subtypes 4a and 4d in Saudi Arabia

    PubMed Central

    Al-Qahtani, Ahmed A.; Baele, Guy; Khalaf , Nisreen; Suchard, Marc A.; Al-Anazi, Mashael R.; Abdo, Ayman A.; Sanai, Faisal M.; Al-Ashgar, Hamad I.; Khan, Mohammed Q.; Al-Ahdal, Mohammed N.; Lemey, Philippe; Vrancken, Bram

    2017-01-01

    The relatedness between viral variants sampled at different locations through time can provide information pertinent to public health that cannot readily be obtained through standard surveillance methods. Here, we use virus genetic data to identify the transmission dynamics that drive the hepatitis C virus subtypes 4a (HCV4a) and 4d (HCV4d) epidemics in Saudi Arabia. We use a comprehensive dataset of newly generated and publicly available sequence data to infer the HCV4a and HCV4d evolutionary histories in a Bayesian statistical framework. We also introduce a novel analytical method for an objective assessment of the migration intensity between locations. We find that international host mobility patterns dominate over within country spread in shaping the Saudi Arabia HCV4a epidemic, while this may be different for the HCV4d epidemic. This indicates that the subtypes 4a and 4d burden can be most effectively reduced by combining the prioritized screening and treatment of Egyptian immigrants with domestic prevention campaigns. Our results highlight that the joint investigation of evolutionary and epidemiological processes can provide valuable public health information, even in the absence of extensive metadata information. PMID:28322313

  17. A Wideband Noise-canceling CMOS LNA Using Cross-coupled Feedback and Bulk Effect

    NASA Astrophysics Data System (ADS)

    Guo, Benqing; Yang, Guoning; An, Shiquan

    2014-05-01

    An improved wideband common-gate (CG) and common-source (CS) CMOS LNA with noise cancellation is proposed. The cross-coupled feedback between the CG input transistor and the cascode transistor of CS input stage is used to increase the input transconductance of the LNA. And the bulk effect of CS input transistors is utilized to enhance gm-boosting coefficient. Thus, comparable gain and noise are achieved by reduced bias currents of the LNA while the resulted additional NF degradation is negligible. Fabricated in a 0.13 μm RF CMOS process, the LNA achieves a flat voltage gain of 18 dB, an NF of 2.7~3.2 dB, and an IIP3 of -4.5~-7.4 dBm over a 3 dB bandwidth of 0.1~4.4 GHz. It consumes only 4.1 mA from a 1 V supply and occupies an area of 520 × 490 um2. In contrast to those of reported wideband LNAs, the proposed LNA has the merit of lower power consumption and lower supply voltage.

  18. Effective Supergravity from the Weakly Coupled HeteroticString

    SciTech Connect

    Gaillard, Mary K.

    2005-05-01

    The motivation for Calabi-Yau-like compactifications of the weakly coupled E{sub 8} {circle_times} E{sub 8} heterotic string theory, its particle spectrum and the issue of dilaton stabilization are briefly reviewed. Modular invariant models for hidden sector condensation and supersymmetry breaking are described at the quantum level of the effective field theory. Their phenomenological and cosmological implications, including a possible origin for R-parity, are discussed.

  19. Bending effect on fiber acousto-optic mode coupling.

    PubMed

    Zhao, Jianhui; Liu, Xiaoming; Wang, Yan; Luo, Ye

    2005-08-20

    The acousto-optic effect in a bent fiber is studied experimentally and numerically by using the scalar finite-element method. The resulting transmission spectra show that new mode-coupling peaks appear due to the breaking of the mode spatial symmetry. The strength of new peaks increases as the fiber-bending curvature increases with a redshift or blueshift in wavelength, strongly depending on the orientation of fiber bending with respect to the acoustic-wave vibration direction.

  20. Acquired Immune Deficiency Syndrome: A Preliminary Examination of the Effects on Gay Couples and Coupling.

    ERIC Educational Resources Information Center

    Carl, Douglas

    1986-01-01

    The Acquired Immune Deficiency Syndrome (AIDS) epidemic significantly influences attitudes about life and lifestyles. Homosexuals have to give increased consideration to coupling, the nature of coupled relationships, sex and intimacy, and death long before the normal time. Discusses impact of AIDS on the early stages of gay coupling and on the…

  1. Acquired Immune Deficiency Syndrome: A Preliminary Examination of the Effects on Gay Couples and Coupling.

    ERIC Educational Resources Information Center

    Carl, Douglas

    1986-01-01

    The Acquired Immune Deficiency Syndrome (AIDS) epidemic significantly influences attitudes about life and lifestyles. Homosexuals have to give increased consideration to coupling, the nature of coupled relationships, sex and intimacy, and death long before the normal time. Discusses impact of AIDS on the early stages of gay coupling and on the…

  2. Applying a 4D multiscale in vivo tumor growth model to the exploration of radiotherapy scheduling: The effects of weekend treatment gaps and p53 gene status on the response of fast growing solid tumors

    PubMed Central

    Dionysiou, Dimitra D.; Stamatakos, Georgios S.

    2006-01-01

    The present paper aims at demonstrating clinically oriented applications of the multiscale four dimensional in vivo tumor growth simulation model previously developed by our research group. To this end the effect of weekend radiotherapy treatment gaps and p53 gene status on two virtual glioblastoma tumors differing only in p53 gene status is investigated in silico. Tumor response predictions concerning two rather extreme dose fractionation schedules (daily dose of 4.5 Gy administered in 3 equal fractions) namely HART (Hyperfractionated Accelerated Radiotherapy weekend less) 54 Gy and CHART (Continuous HART) 54 Gy are presented and compared. The model predictions suggest that, for the same p53 status, HART 54 Gy and CHART 54 Gy have almost the same long term effects on locoregional tumor control. However, no data have been located in the literature concerning a comparison of HART and CHART radiotherapy schedules for glioblastoma. As non small cell lung carcinoma (NSCLC) may also be a fast growing and radiosensitive tumor, a comparison of the model predictions with the outcome of clinical studies concerning the response of NSCLC to HART 54 Gy and CHART 54 Gy is made. The model predictions are in accordance with corresponding clinical observations, thus strengthening the potential of the model. PMID:19458763

  3. Inertial effect on spin-orbit coupling and spin transport

    NASA Astrophysics Data System (ADS)

    Basu, B.; Chowdhury, Debashree

    2013-08-01

    We theoretically study the renormalization of inertial effects on the spin dependent transport of conduction electrons in a semiconductor by taking into account the interband mixing on the basis of k→ṡp→ perturbation theory. In our analysis, for the generation of spin current we have used the extended Drude model where the spin-orbit coupling plays an important role. We predict enhancement of the spin current resulting from the renormalized spin-orbit coupling effective in our model in cubic and non-cubic crystals. Attention has been paid to clarify the importance of gauge fields in the spin transport of this inertial system. A theoretical proposition of a perfect spin filter has been done through the Aharonov-Casher like phase corresponding to this inertial system. For a time dependent acceleration, effect of k→ ṡp→ perturbation on the spin current and spin polarization has also been addressed. Furthermore, achievement of a tunable source of polarized spin current through the non uniformity of the inertial spin-orbit coupling strength has also been discussed.

  4. Investigating digit ratio (2D:4D) in a highly male-dominated occupation: the case of firefighters.

    PubMed

    Voracek, Martin; Pum, Ulrike; Dressler, Stefan G

    2010-04-01

    Second-to-fourth digit ratio (2D:4D), a widely studied putative marker for masculinization through prenatal androgen exposure, is lower (more masculinized) in athletes than in general population controls, and athletes with lower 2D:4D have higher sporting success. Occupations differ markedly in perceived masculinity and actual maleness (sex ratios), but these givens have not yet been picked up and utilized in 2D:4D research. Accordingly, this study extended existing accounts on 2D:4D in athletes to a novel approach: 2D:4D and possible relationships to a variety of candidate variables (demographic, fertility-related, psychological, and other) were investigated in firefighters, a highly male-dominated occupation. Contrary to expectation, 2D:4D in firefighters (N = 134) was not lower than in local male population controls. Lower 2D:4D corresponded to lower service ranks. Replicating previous findings either unequivocally or partly, lower 2D:4D was associated with larger family size, later sibling position, left-handedness, and higher scores in the disinhibition component of sensation seeking. Not replicating prior evidence, 2D:4D was unrelated to body-mass index, offspring sex ratio, and sporting performance level. Novel findings included low 2D:4D in those with low relationship satisfaction and in cigarette smokers, especially among heavy smokers. Absolute finger length, a positive correlate of pubertal-adolescent androgen levels, was also considered. This marker showed negative associations with relationship consensus and satisfaction and positive ones with perceived quality of relationship alternatives and the experience seeking component of sensation seeking. The merits of this additional marker, relative to 2D:4D, for supplementing studies of possible sex-hormonal effects on personality and directions for future inquiry along these lines are discussed.

  5. Second to fourth digit ratio (2D:4D) and concentrations of circulating sex hormones in adulthood.

    PubMed

    Muller, David C; Giles, Graham G; Bassett, Julie; Morris, Howard A; Manning, John T; Hopper, John L; English, Dallas R; Severi, Gianluca

    2011-04-27

    The second to fourth digit ratio (2D:4D) is used as a marker of prenatal sex hormone exposure. The objective of this study was to examine whether circulating concentrations of sex hormones and SHBG measured in adulthood was associated with 2D:4D. This analysis was based on a random sample from the Melbourne Collaborative Cohort Study. The sample consisted of of 1036 men and 620 post-menopausal women aged between 39 and 70 at the time of blood draw. Concentrations of circulating sex hormones were measured from plasma collected at baseline (1990-1994), while digit length was measured from hand photocopies taken during a recent follow-up (2003-2009). The outcome measures were circulating concentrations of testosterone, oestradiol, dehydroepiandrosterone sulphate, androstenedione, Sex Hormone Binding Globulin, androstenediol glucoronide for men only and oestrone sulphate for women only. Free testosterone and oestradiol were estimated using standard formulae derived empirically. Predicted geometric mean hormone concentrations (for tertiles of 2D:4D) and conditional correlation coefficients (for continuous 2D:4D) were obtained using mixed effects linear regression models. No strong associations were observed between 2D:4D measures and circulating concentrations of hormones for men or women. For males, right 2D:4D was weakly inversely associated with circulating testosterone (predicted geometric mean testosterone was 15.9 and 15.0 nmol/L for the lowest and highest tertiles of male right 2D:4D respectively (P-trend = 0.04). There was a similar weak association between male right 2D:4D and the ratio of testosterone to oestradiol. These associations were not evident in analyses of continuous 2D:4D. There were no strong associations between any adult circulating concentration of sex hormone or SHGB and 2D:4D. These results contribute to the growing body of evidence indicating that 2D:4D is unrelated to adult sex hormone concentrations.

  6. Increased ratio of 2nd to 4th digit (2D:4D) in schizophrenia.

    PubMed

    Collinson, Simon Lowes; Lim, Matthew; Chaw, Jia Hui; Verma, Swapna; Sim, Kang; Rapisarda, Attilio; Chong, Siow Ann

    2010-03-30

    Sex differences in the onset, epidemiology, clinical presentation and neuropathology of schizophrenia suggest that sexual dimorphism in brain development may be relevant to pathogenesis. Sex hormones, in particular testosterone, are considered to be crucial in brain development, but few investigations have examined the potential role of prenatal testosterone in schizophrenia. In this study, we examined a retrospective marker of prenatal testosterone release - 2D:4D finger length ratio (2D:4D), the relative length of 2nd to 4th digit, in 64 Asian patients with schizophrenia and 64 sex-matched controls. No significant difference in mean finger lengths was present, however 2D:4D ratio was significantly different between patients and controls. The effect was primarily seen in males consistent with a 'less masculinised' pattern and hypotheses suggesting that schizophrenia may be associated with an abnormality in prenatal circulating testosterone. Copyright 2009 Elsevier Ireland Ltd. All rights reserved.

  7. Soccer players awarded one or more red cards exhibit lower 2D:4D ratios.

    PubMed

    Mailhos, Alvaro; Buunk, Abraham P; Del Arca, Denise; Tutte, Verónica

    2016-09-01

    Anatomical, cognitive and behavioral sex differences are widely recognized in many species. It has been proposed that some of these differences might result from the organizing effects of prenatal sex steroids. In humans, males usually exhibit higher levels of physical aggression and prowess. In this study, we analyze the relationship between second-to-fourth digit (2D:4D) ratios-a proxy for prenatal androgen levels-and foul play and sporting performance in a sample of junior soccer players from a professional Uruguayan soccer club. Our results show that the most aggressive players (i.e., those awarded one or more red cards) have a more masculine finger pattern (lower 2D:4D ratio), while no relationship could be found between sporting performance and 2D:4D ratios. The results are discussed in the context of previous findings. Aggr. Behav. 42:417-426, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  8. The technology and performance of 4D ultrasound.

    PubMed

    Obruchkov, Sergei

    2008-01-01

    Recent developments in 4D ultrasound imaging technology allow clinicians to obtain not only rich visual information but also quantitative data that can be used for diagnosis and treatment. Some argue that the extension of 2D ultrasound is unnecessary and does not offer any benefits to diagnosis, while others argue that it is possible to better assess an abnormality in 3D than 2D. Anatomy can be reconstructed in perspectives that were never seen with conventional 2D US imaging. Advanced rendering techniques in three dimensions can be customized to be sensitive to specific pathology, thus making diagnosis more accurate. Volume and function of certain anatomical components can be measured with greater accuracy. This article reviews physical principles behind the ultrasound technology, how they are applied to advance the field of ultrasound imaging, and maybe reach its limits. Advances in ultrasound technology make 4D ultrasound imaging faster and less dependent on the operator's expertise, thus opening up more research possibilities in the fields of data processing and visualization. Currently, 4D ultrasound is extensively used in the field of obstetrics and interven-tional radiology. The goal of 4D ultrasound is to overcome the limitations posed by its predecessor technology and to be more clinically useful as an imaging tool.

  9. Enterococcus faecalis promotes osteoclastogenesis and semaphorin 4D expression.

    PubMed

    Wang, Shuai; Deng, Zuhui; Seneviratne, Chaminda J; Cheung, Gary S P; Jin, Lijian; Zhao, Baohong; Zhang, Chengfei

    2015-10-01

    Enterococcus faecalis is considered a major bacterial pathogen implicated in endodontic infections and contributes considerably to periapical periodontitis. This study aimed to investigate the potential mechanisms by which E. faecalis accounts for the bone destruction in periapical periodontitis in vitro. Osteoclast precursor RAW264.7 cells were treated with E. faecalis ATCC 29212 and a wild strain of E. faecalis derived clinically from an infected root canal. The results showed that, to some extent, E. faecalis induced the RAW264.7 cells to form tartrate-resistant acid phosphatase (TRAP)-positive multinucleated osteoclast-like cells. This pathogen markedly stimulated RAW264.7 cells to express semaphorin 4D (Sema4D), which inhibits bone formation. Once RAW264.7 cells were primed by low-dose receptor activator of nuclear factor-kappa B ligand (RANKL), E. faecalis could significantly increase the production of TRAP-positive multinucleated cells and up-regulate the expression of osteoclast-specific markers, including NFATc1, TRAP and cathepsin K. Both p38 and ERK1/2 MAPK signaling pathways were activated by E. faecalis in RANKL-primed RAW264.7 cells, and meanwhile the expression of Sema4D was highly increased. In conclusion, E. faecalis may greatly contribute to the bone resorption in periapical periodontitis by promoting RANKL-dependent osteoclastogenesis and expression of Sema4D through activation of p38 and ERK1/2 MAPK signaling pathways.

  10. 76 FR 55814 - 2,4-D; Pesticide Tolerances

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-09

    ...: Final rule. SUMMARY: This regulation establishes tolerances for residues of 2,4-D in or on teff, bran; teff, forage; teff, grain; and teff, straw. Interregional Research Project Number 4 (IR-4) requested...-dichlorophenoxyacetic acid), both free and conjugated, determined as the acid, in or on teff, bran at 4.0 parts per...

  11. 2,4-Dichlorophenoxyacetic acid (2,4-D)

    Integrated Risk Information System (IRIS)

    2,4 - Dichlorophenoxyacetic acid ( 2,4 - D ) ; CASRN 94 - 75 - 7 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Asses

  12. Cotton stage of growth determines sensitivityto 2,4-D

    USDA-ARS?s Scientific Manuscript database

    The impending release of EnlistTM cotton and soybean cultivars likely will increase the use of 2,4-D, which has raised concerns over potential injury to susceptible cotton. An experiment was conducted at 12 locations across the cotton belt during 2013 and 2014 to determine the impact of a simulated...

  13. [Free hand acquisition, reconstruction and visualization of 3D and 4D ultrasound].

    PubMed

    Sakas, G; Walter, S; Grimm, M; Richtscheid, M

    2000-03-01

    3D Ultrasound will find in the next years a wide popularity under the medical imaging applications. The method expands the well-known sonography on the third dimension, therefore it becomes possible to generate spatial 3D views of internal organs. It is further possible to display static (3D) as well as dynamic organs (4D, e.g. pulsating heart). The clarity of the three-dimensional presentation supports very effectively the navigation. In this article we review the upgrading of conventional ultrasound devices on 3D and 4D capabilities, as well as the display of the datasets by corresponding visualisation and filtering approaches.

  14. Use of 4-D atmospheric models in the simulation of radiometric measurements

    NASA Technical Reports Server (NTRS)

    Chang, D. T.; Fowler, M. G.

    1973-01-01

    Atmospheric moisture data contained in the Global 4-D Atmospheric Models developed in previous studies were analyzed to establish regional differences. The regional values of precipitable water along latitudinal belts were compared with values derived from the corresponding atmospheric models defined in the U.S Standard Atmosphere Supplement. The effects of the differences between the 4-D Models and the Standard Atmosphere Models on radiometric computations in the infrared window and water vapor absorption band regions were evaluated using a standard computation model of radiation transfer through a cloudless atmosphere. The significance of these differences in simulation is discussed.

  15. Effect of strongly coupled plasma on photoionization cross section

    SciTech Connect

    Das, Madhusmita

    2014-01-15

    The effect of strongly coupled plasma on the ground state photoionization cross section is studied. In the non relativistic dipole approximation, cross section is evaluated from bound-free transition matrix element. The bound and free state wave functions are obtained by solving the radial Schrodinger equation with appropriate plasma potential. We have used ion sphere potential (ISP) to incorporate the plasma effects in atomic structure calculation. This potential includes the effect of static plasma screening on nuclear charge as well as the effect of confinement due to the neighbouring ions. With ISP, the radial equation is solved using Shooting method approach for hydrogen like ions (Li{sup +2}, C{sup +5}, Al{sup +12}) and lithium like ions (C{sup +3}, O{sup +5}). The effect of strong screening and confinement is manifested as confinement resonances near the ionization threshold for both kinds of ions. The confinement resonances are very much dependent on the edge of the confining potential and die out as the plasma density is increased. Plasma effect also results in appearance of Cooper minimum in lithium like ions, which was not present in case of free lithium like ions. With increasing density the position of Cooper minimum shifts towards higher photoelectron energy. The same behaviour is also true for weakly coupled plasma where plasma effect is modelled by Debye-Huckel potential.

  16. Biological and molecular responses of Chironomus riparius (Diptera, Chironomidae) to herbicide 2,4-D (2,4-dichlorophenoxyacetic acid).

    PubMed

    Park, Kiyun; Park, Jungan; Kim, Jongkyu; Kwak, Inn-Sil

    2010-05-01

    2,4-Dichlorophenoxyacetic acid (2,4-D) is an agricultural contaminant found in rural ground water. It remains to be determined whether neither 2,4-D poses environmental risks, nor is the mechanism of toxicity known at the molecular level. To evaluate the potential ecological risk of 2,4-D, we assessed the biological parameters including the survival rate, adult sex ratio of emerged adults, and mouthpart deformities in Chironomus riparius after long-term exposure to 2,4-D. The larvae were treated with 0.1, 1 or, 10microgL(-1) of 2,4-D for short- and long-term exposure periods. The sex ratio was changed in C. riparius exposed to only 10microgL(-1) of 2,4-D, whereas mouthpart deformities were observed as significantly higher in C. riparius exposed to 0.1microgL(-1) of 2,4-D. Survival rates were not significantly affected by 2,4-D. Furthermore, we evaluated the molecular and biochemical responses of biomarker genes such as gene expression of heat shock proteins (HSPs), ferritins and glutathione S-transferases (GSTs) in C. riparius exposed to 2,4-D for 24h. The expressions of HSP70, HSP40, HSP90 and GST levels in C. riparius were significantly increased after exposure to a 10microgL(-1) concentration of 2,4-D, whereas ferritin heavy and light chain gene expressions were significantly increased at all concentrations of 2,4-D exposure. Finally, these results may provide an important contribution to our understanding of the toxicology of 2,4-D herbicide in C. riparius. Moreover, the 2,4-D-mediated gene expressions may be generated by 2,4-D is the causative effects on most probable cause of the observed alterations. These biological, molecular and morphological parameters and the measured parameters can be used to monitor 2,4-D toxicity in an aquatic environment. Copyright 2010 Elsevier Inc. All rights reserved.

  17. 4D imaging of protein aggregation in live cells.

    PubMed

    Spokoini, Rachel; Shamir, Maya; Keness, Alma; Kaganovich, Daniel

    2013-04-05

    ubiquitinated are diverted to the IPOD, where they are actively aggregated in a protective compartment. Up until this point, the methodological paradigm of live-cell fluorescence microscopy has largely been to label proteins and track their locations in the cell at specific time-points and usually in two dimensions. As new technologies have begun to grant experimenters unprecedented access to the submicron scale in living cells, the dynamic architecture of the cytosol has come into view as a challenging new frontier for experimental characterization. We present a method for rapidly monitoring the 3D spatial distributions of multiple fluorescently labeled proteins in the yeast cytosol over time. 3D timelapse (4D imaging) is not merely a technical challenge; rather, it also facilitates a dramatic shift in the conceptual framework used to analyze cellular structure. We utilize a cytosolic folding sensor protein in live yeast to visualize distinct fates for misfolded proteins in cellular aggregation quality control, using rapid 4D fluorescent imaging. The temperature sensitive mutant of the Ubc9 protein (Ubc9(ts)) is extremely effective both as a sensor of cellular proteostasis, and a physiological model for tracking aggregation quality control. As with most ts proteins, Ubc9(ts) is fully folded and functional at permissive temperatures due to active cellular chaperones. Above 30 ° C, or when the cell faces misfolding stress, Ubc9(ts) misfolds and follows the fate of a native globular protein that has been misfolded due to mutation, heat denaturation, or oxidative damage. By fusing it to GFP or other fluorophores, it can be tracked in 3D as it forms Stress Foci, or is directed to JUNQ or IPOD.

  18. 4D Imaging of Protein Aggregation in Live Cells

    PubMed Central

    Kaganovich, Daniel

    2013-01-01

    proteins that are not ubiquitinated are diverted to the IPOD, where they are actively aggregated in a protective compartment. Up until this point, the methodological paradigm of live-cell fluorescence microscopy has largely been to label proteins and track their locations in the cell at specific time-points and usually in two dimensions. As new technologies have begun to grant experimenters unprecedented access to the submicron scale in living cells, the dynamic architecture of the cytosol has come into view as a challenging new frontier for experimental characterization. We present a method for rapidly monitoring the 3D spatial distributions of multiple fluorescently labeled proteins in the yeast cytosol over time. 3D timelapse (4D imaging) is not merely a technical challenge; rather, it also facilitates a dramatic shift in the conceptual framework used to analyze cellular structure. We utilize a cytosolic folding sensor protein in live yeast to visualize distinct fates for misfolded proteins in cellular aggregation quality control, using rapid 4D fluorescent imaging. The temperature sensitive mutant of the Ubc9 protein10-12 (Ubc9ts) is extremely effective both as a sensor of cellular proteostasis, and a physiological model for tracking aggregation quality control. As with most ts proteins, Ubc9ts is fully folded and functional at permissive temperatures due to active cellular chaperones. Above 30 °C, or when the cell faces misfolding stress, Ubc9ts misfolds and follows the fate of a native globular protein that has been misfolded due to mutation, heat denaturation, or oxidative damage. By fusing it to GFP or other fluorophores, it can be tracked in 3D as it forms Stress Foci, or is directed to JUNQ or IPOD. PMID:23608881

  19. Digit ratio (2D:4D), dominance, reproductive success, asymmetry, and sociosexuality in the BBC Internet Study.

    PubMed

    Manning, John T; Fink, Bernhard

    2008-01-01

    Digit ratio (2D:4D) may be a correlate of prenatal sex steroids, and has been linked to traits, which are influenced by fetal testosterone and estrogen. Here we consider such links in a large Internet study of sex differences (the BBC Internet Study) in which finger lengths were self-measured. Consistent with lab-based findings the 2D:4D in this study shows sexual dimorphism, ethnic differences and higher dimorphism of right 2D:4D than left, thereby indicating that 2D:4D does measure real between-participant variation. High error in self-measurement of fingers reduces effect sizes. However, the large sample size gives assurance that significant effects are likely to be real. We controlled for ethnicity and sexual orientation by considering White heterosexuals only (153,429 participants). Sexual dimorphism was confirmed in 2D:4D and for the difference of right-left 2D:4D. After Bonferroni correction we found highly significant relationships with low effect sizes as follows. In males and females there were negative associations between 2D:4D and dominance. In males there were negative associations between 2D:4D and family size and factors associated with reproductive success. For females these associations were positive. For asymmetry we found U-shaped relationships with 2D:4D in both males and females. We found no relationship between 2D:4D and promiscuity (sociosexuality). In total, we considered 48 relationships and found 29 to be significant. We compare our findings with a similar study reported by Putz et al. (2004), which found only 2 out of 57 correlations to be significant and discuss possible reasons for the discrepancies between the studies.

  20. Impact of Petrophysical Experiments on Quantitative Interpretation of 4D Seismic Data at Ketzin, Germany

    NASA Astrophysics Data System (ADS)

    Ivanova, A.; Lueth, S.

    2015-12-01

    Petrophysical investigations for CCS concern relationships between physical properties of rocks and geophysical observations for understanding behavior of injected CO2 in a geological formation. In turn 4D seismic surveying is a proven tool for CO2 monitoring. At the Ketzin pilot site (Germany) 4D seismic data have been acquired by means of a baseline (pre-injection) survey in 2005 and monitor surveys in 2009 and 2012. At Ketzin CO2 was injected in supercritical state from 2008 to 2013 in a sandstone saline aquifer (Stuttgart Formation) at a depth of about 650 m. The 4D seismic data from Ketzin reflected a pronounced effect of this injection. Seismic forward modeling using results of petrophysical experiments on two core samples fromthe target reservoir confirmed that effects of the injected CO2 on the 4D seismic data are significant. The petrophysical data were used in that modeling in order to reflect changes due to the CO2 injection in acoustic parameters of the reservoir. These petrophysical data were further used for a successful quantitative interpretation of the 4D seismic data at Ketzin. Now logs from a well (drilled in 2012) penetrating the reservoir containing information about changes in the acoustic parameters of the reservoir due to the CO2 injection are available. These logs were used to estimate impact of the petrophysical data on the qualitative and quantitative interpretation of the 4D seismic data at Ketzin. New synthetic seismograms were computed using the same software and the same wavelet as the old ones apart from the only difference and namely the changes in the input acoustic parameters would not be affected with any petrophysical experiments anymore. Now these changes were put in computing directly from the logs. In turn the new modelled changes due to the injection in the newly computed seismograms do not include any effects of the petrophysical data anymore. Key steps of the quantitative and qualitative interpretation of the 4D seismic

  1. The twin condition and the couple effects on personality development.

    PubMed

    Zazzo, R

    1976-01-01

    Twin psychology has been studied to a very limited extent. Only few remarkable peculiarities of the twins' development are known for sure, such as delayed intellectual development, language retardation with frequent cryptophasia, difficulties and fragility of self consciousness, reduced sociability. These and other peculiarities may result from a number of different factors: biological, peculiar parental attitude, and especially the twin situation itself, the psychology of the twin as an individual being a function of the psychology of the twin pair. Twin peculiarities have for a long time been ignored. On the one hand, psychology ignored the couple reality (it was a "one-body" psychology), and on the other, the twin method classically postulated that twins are not atypical and may therefore be used as a test for the general population. As a matter of fact, twin psychology opens a new way to science. The twin situation may serve as a paradigm for the general study of the couple effect, namely, for the objective analysis of personality as a consequence of the relations between self and others. For certain traits of personality, it is already known that MZ twins brought-up together are significantly less similar than MZ twins brought-up apart. In fact, couple effects may mask or considerably reduce genetic factors.

  2. Effective Potential Theory for Transport Coefficients across Coupling Regimes

    NASA Astrophysics Data System (ADS)

    Baalrud, Scott D.

    2013-10-01

    Plasmas in several modern experiments, including dense, ultracold and dusty plasmas, can reach strong coupling where the Coulomb potential energy of interacting particles exceeds their average kinetic energy. Understanding how the many-body physics of correlations affects plasma transport properties in this regime is interesting both from a basic physics standpoint and as a practical matter. Transport coefficients are essential input required for accurate hydrodynamic modeling of these systems, which can include weakly coupled and strongly coupled components simultaneously. We discuss a physically motivated extension of plasma transport theory that is computationally efficient and versatile enough that it can be applied to essentially any transport property. Like conventional plasma theories, ours is based on a binary collision picture, but where particles interact via an effective potential that accounts for average affects of the intervening medium. This includes both correlations and screening. Hypernetted chain (HNC) theory, which is a well-established approximation for the pair correlation function, is used to derive the effective potential. The theory is shown to compare well with ion velocity relaxation in an ultracold plasma experiment, as well as classical molecular dynamics simulations of temperature relaxation in electron-ion plasmas, and diffusion in both one-component plasmas and ionic mixtures. This research was conducted in collaboration with Jerome Daligault and was supported by a Richard P. Feynman Postdoctoral Fellowship and the LDRD program at Los Alamos National Laboratory.

  3. Superstrate effects on slot-coupled microstrip antennas

    NASA Astrophysics Data System (ADS)

    Huang, Chang-Hsiu; Hsu, Powen

    1991-09-01

    An analysis for studying the superstrate (cover) effects on the slot-coupled microstrip antennas is presented. The approach is based on the reciprocity theorem and uses the grounded double- and single-layer dielectric slab Green's functions in a moment method solution for the unknown slot fields and patch currents. From these fields and currents, various characteristics of the antenna can be extracted, such as the radiation efficiency, directivity, input impedance, and resonant frequency. Numerical calculations showing superstrate effects on these antenna characteristics are presented. The input matches obtained from proper adjustment of the slot and patch dimensions are discussed.

  4. An effective field theory for coupled-channel scattering

    NASA Astrophysics Data System (ADS)

    Cohen, Thomas D.; Gelman, Boris A.; van Kolck, U.

    2004-05-01

    The problem of describing low-energy two-body scattering for systems with two open channels with different thresholds is addressed in the context of an effective field theory. In particular, the problem where the threshold is unnaturally small and the cross section at low energy is unnaturally large is considered. It is shown that the lowest-order point coupling associated with the mixing of the channels scales as Λ-2 rather than Λ-1 (the scaling of the same-channel coupling and the scaling in a single-channel case) where Λ is the ultraviolet cutoff. The renormalization of the theory at lowest order is given explicitly. The treatment of higher orders is straightforward. The potential implications for systems with deep open channels are discussed.

  5. Effect of Cognitive-Behavioral Couple Therapy for PTSD

    PubMed Central

    Monson, Candice M.; Fredman, Steffany J.; Macdonald, Alexandra; Pukay-Martin, Nicole D.; Resick, Patricia A.; Schnurr, Paula P.

    2015-01-01

    .21; 95% CI, −37.87 to −8.55). Similarly, patients’ intimate relationship satisfaction (score range, 0–151) was significantly more improved in couple therapy than in the wait-list condition (mean change difference, 9.43; 95% CI, 0.04–18.83). The time×condition interaction effect in the multilevel model predicting PTSD symptoms (t37.5=−3.09; P =.004) and patient-reported relationship satisfaction (t68.5=2.00; P=.049) revealed superiority of the couple therapy compared with the wait list. Treatment effects were maintained at 3-month follow-up. Conclusion Among couples in which one partner was diagnosed as having PTSD, a disorder-specific couple therapy, compared with a wait list for the therapy, resulted in decreased PTSD symptom severity and patient comorbid symptom severity and increased patient relationship satisfaction. Trial Registration clinicaltrials.gov Identifier: NCT00669981 PMID:22893167

  6. Synthesis and antiviral activity of some C2-, C4-, and C6-substituted pyrazolo[3,4-D]pyrimidine acyclonucleosides with the alkylating chains of ACV, HBG, and ISO-DHPG.

    PubMed

    Moukha-Chafiq, Omar; Taha, Mohamed Labd; Lazrek, Hassan Bihi; Vasseur, Jean-Jacques; Clercq, Erik De

    2006-01-01

    A useful route to obtain trisubstituted pyrazolo[3,4-d]pyrimidines 14-17 is described. Those later were coupled with the alkylating agents 18-20 as in ACV, HBG, and iso-DHPG to give, after deprotection, the desired acylonucleosides 33-44. Almost all of the new compounds were evaluated for their inhibitory effects against the replication of various DNA viruses in culture.

  7. Interactive 4D Visualization of Sediment Transport Models

    NASA Astrophysics Data System (ADS)

    Butkiewicz, T.; Englert, C. M.

    2013-12-01

    Coastal sediment transport models simulate the effects that waves, currents, and tides have on near-shore bathymetry and features such as beaches and barrier islands. Understanding these dynamic processes is integral to the study of coastline stability, beach erosion, and environmental contamination. Furthermore, analyzing the results of these simulations is a critical task in the design, placement, and engineering of coastal structures such as seawalls, jetties, support pilings for wind turbines, etc. Despite the importance of these models, there is a lack of available visualization software that allows users to explore and perform analysis on these datasets in an intuitive and effective manner. Existing visualization interfaces for these datasets often present only one variable at a time, using two dimensional plan or cross-sectional views. These visual restrictions limit the ability to observe the contents in the proper overall context, both in spatial and multi-dimensional terms. To improve upon these limitations, we use 3D rendering and particle system based illustration techniques to show water column/flow data across all depths simultaneously. We can also encode multiple variables across different perceptual channels (color, texture, motion, etc.) to enrich surfaces with multi-dimensional information. Interactive tools are provided, which can be used to explore the dataset and find regions-of-interest for further investigation. Our visualization package provides an intuitive 4D (3D, time-varying) visualization of sediment transport model output. In addition, we are also integrating real world observations with the simulated data to support analysis of the impact from major sediment transport events. In particular, we have been focusing on the effects of Superstorm Sandy on the Redbird Artificial Reef Site, offshore of Delaware Bay. Based on our pre- and post-storm high-resolution sonar surveys, there has significant scour and bedform migration around the

  8. Experimental study of the degradation of 2,4-D induced by vacuum-UV radiation.

    PubMed

    Imoberdorf, G E; Mohseni, M

    2011-01-01

    Vacuum-UV (VUV) photoinduced degradation of the herbicide 2,4-D was studied. A flow-through VUV photoreactor was used (i) in batch mode to study the kinetics of degradation and (ii) in continuous mode under steady state to analyze the potential utilization of this process in commercial applications. In both cases, the reactants were recycled to minimize diffusive resistances. Experimental results from the batch studies showed that the initial degradation rate of 2,4-D in ultrapure water was independent of the initial concentration of the herbicide. However, a reduction in the reaction rate was obtained over the course of the treatment, largely due to the formation of 2,4-D partial oxidation by-products which compete with 2,4-D molecules for HO (scavenging effect). Increases in water alkalinity reduced 2,4-D degradation rate as a consequence of the scavenging of HO by carbonates and bicarbonates. The degradation of 2,4-D in raw surface waters was also investigated. A noticeable reduction in the degradation rate was observed because of the presence of NOM and alkalinity, both being known HO scavengers. Additionally, the presence of inorganic species/ions that absorb VUV may also have contributed to the reduction of the overall degradation rate. High conversions were obtained in the continuous system. At a residence time of 25 seconds, conversions of 97% and 65% were achieved for inlet herbicide concentrations of 1 and 10 mg L(-1), respectively. Under these conditions, the received dose of 185 nm radiation was 44.8 mJ cm(-2).

  9. Advances in 4D Treatment Planning for Scanned Particle Beam Therapy — Report of Dedicated Workshops

    PubMed Central

    Bert, Christoph; Graeff, Christian; Riboldi, Marco; Nill, Simeon; Baroni, Guido; Knopf, Antje-Christin

    2014-01-01

    We report on recent progress in the field of mobile tumor treatment with scanned particle beams, as discussed in the latest editions of the 4D treatment planning workshop. The workshop series started in 2009, with about 20 people from 4 research institutes involved, all actively working on particle therapy delivery and development. The first workshop resulted in a summary of recommendations for the treatment of mobile targets, along with a list of requirements to apply these guidelines clinically. The increased interest in the treatment of mobile tumors led to a continuously growing number of attendees: the 2012 edition counted more than 60 participants from 20 institutions and commercial vendors. The focus of research discussions among workshop participants progressively moved from 4D treatment planning to complete 4D treatments, aiming at effective and safe treatment delivery. Current research perspectives on 4D treatments include all critical aspects of time resolved delivery, such as in-room imaging, motion detection, beam application, and quality assurance techniques. This was motivated by the start of first clinical treatments of hepato cellular tumors with a scanned particle beam, relying on gating or abdominal compression for motion mitigation. Up to date research activities emphasize significant efforts in investigating advanced motion mitigation techniques, with a specific interest in the development of dedicated tools for experimental validation. Potential improvements will be made possible in the near future through 4D optimized treatment plans that require upgrades of the currently established therapy control systems for time resolved delivery. But since also these novel optimization techniques rely on the validity of the 4DCT, research focusing on alternative 4D imaging technique, such as MRI based 4DCT generation will continue. PMID:24354749

  10. Complement Factor C4d Is a Common Denominator in Thrombotic Microangiopathy

    PubMed Central

    Baelde, Hans J.; Zandbergen, Malu; Wilhelmus, Suzanne; van Es, Leendert A.; de Fijter, Johan W.; Bruijn, Jan A.; Bajema, Ingeborg M.; Cohen, Danielle

    2015-01-01

    Complement activation has a major role in thrombotic microangiopathy (TMA), a disorder that can occur in a variety of clinical conditions. Promising results of recent trials with terminal complement-inhibiting drugs call for biomarkers identifying patients who might benefit from this treatment. The primary aim of this study was to determine the prevalence and localization of complement factor C4d in kidneys of patients with TMA. The secondary aims were to determine which complement pathways lead to C4d deposition and to determine whether complement activation results in deposition of the terminal complement complex. We examined 42 renal sections with histologically confirmed TMA obtained from a heterogeneous patient group. Deposits of C4d, mannose-binding lectin, C1q, IgM, and C5b-9 were scored in the glomeruli, peritubular capillaries, and arterioles. Notably, C4d deposits were present in 88.1% of TMA cases, and the various clinical conditions had distinct staining patterns within the various compartments of the renal vasculature. Classical pathway activation was observed in 90.5% of TMA cases. C5b-9 deposits were present in 78.6% of TMA cases and in 39.6% of controls (n=53), but the staining pattern differed between cases and controls. In conclusion, C4d is a common finding in TMA, regardless of the underlying clinical condition. Moreover, C5b-9 was present in >75% of the TMA samples, suggesting that terminal complement inhibitors may have a beneficial effect in these patients. C4d and C5b-9 should be investigated as possible diagnostic biomarkers in the clinical work-up of patients suspected of having complement-mediated TMA. PMID:25573909

  11. Digit ratio (2D:4D) and gender inequalities across nations.

    PubMed

    Manning, John T; Fink, Bernhard; Trivers, Robert

    2014-08-22

    Gender inequality varies across nations, where such inequality is defined as the disproportionate representation of one sex over the other in desirable social, economic, and biological roles (typically male over female). Thus in Norway, 40% of parliamentarians are women, in the USA 17%, and in Saudi Arabia 0%. Some of this variation is associated with economic prosperity but there is evidence that this cause and effect can go in either direction. Here we show that within a population the average ratio of index (2D) to ring (4D) finger lengths (2D:4D)-a proxy measure of the relative degree to which offspring is exposed in utero to testosterone versus estrogen-is correlated with measures of gender inequality between nations. We compared male and female 2D:4D ratios to female parliamentary representation, labor force participation, female education level, maternal mortality rates, and juvenile pregnancy rates per nation in a sample of 29 countries. We found those nations who showed higher than expected female fetal exposure to testosterone (low 2D:4D) and lower than expected male exposure to fetal testosterone (high 2D:4D) had higher rates of female parliamentary representation, and higher female labor force participation. In short, the more similar the two sexes were in 2D:4D, the more equal were the two sexes in parliamentary and labor force participation. The other variables were not as strongly correlated. We suggest that higher than expected fetal testosterone in females and lower fetal testosterone in males may lead to high female representation in the national labor force and in parliament.

  12. SU-E-T-790: Validation of 4D Measurement-Guided Dose Reconstruction (MGDR) with OCTAVIUS 4D System

    SciTech Connect

    Lee, V; Leung, R; Wong, M; Law, G; Lee, K; Tung, S; Chan, M; Blanck, O

    2015-06-15

    Purpose: To validate the MGDR of OCTAVIUS 4D system (PTW, Freiburg, Germany) for quality assurance (QA) of volumetric-modulated arc radiotherapy (VMAT). Methods: 4D-MGDR measurements were divided into two parts: 1) square fields from 2×2 to 25×25 cm{sup 2} at 0°, 10° and 45° gantry, and 2) 8 VMAT plans (5 nasopharyngeal and 3 prostate) collapsed to gantry 40° in QA mode in Monaco v5.0 (Elekta, CMS, Maryland Heights, MO) were delivered on the OCTAVIUS 4D phantom with the OCTAVIUS 1500 detector plane perpendicular to either the incident beam to obtain the reconstructed dose (OCTA4D) or the 0° gantry axis to obtain the raw doses (OCTA3D) in Verisoft 6.1 (PTW, Freiburg, Germany). Raw measurements of OCTA3D were limited to < 45° gantry to avoid >0.5% variation of detector angular response with respect to 0° gantry as determined previously. Reconstructed OCTA4D and raw OCTA3D doses for all plans were compared at the same detector plane using γ criteria of 2% (local dose)/2mm and 3%/3mm criteria. Results: At gantry 0° and 10°, the γ results for all OCTA4D on detector plane coinciding with OCTA3D were over 90% at 2%/2mm except for the largest field (25×25 cm{sup 2} ) showing >88%. For square field at 45° gantry, γ passing rate is > 90% for fields smaller than 15x 15cm2 but < 80% for field size of 20 x20 cm{sup 2} upward. For VMAT, γ results showed 94% and 99% passing rate at 2%/2mm and 3%/3mm, respectively. Conclusion: OCTAVIUS 4D system has compromised accuracy in reconstructing dose away from the central beam axis, possibly due to the off-axis softening correction and errors of the percent depth dose data necessary as input for MGDR. Good results in VMAT delivery suggested that the system is relatively reliable for VMAT with small segments.

  13. Improved Respiratory Navigator Gating for Thoracic 4D flow MRI

    PubMed Central

    van Ooij, Pim; Semaan, Edouard; Schnell, Susanne; Giri, Shivraman; Stankovic, Zoran; Carr, James; Barker, Alex J.; Markl, Michael

    2016-01-01

    Background Thoracic and abdominal 4D flow MRI is typically acquired in combination with navigator respiration control which can result in highly variable scan efficiency (Seff) and thus total scan time due to inter-individual variability in breathing patterns. The aim of this study was to test the feasibility of an improved respiratory control strategy based on diaphragm navigator gating with fixed Seff, respiratory driven phase encoding, and a navigator training phase. Methods 4D flow MRI of the thoracic aorta was performed in 10 healthy subjects at 1.5T and 3T systems for the in-vivo assessment of aortic time-resolved 3D blood flow velocities. For each subject, four 4D flow scans (1: conventional navigator gating, 2–4: new implementation with fixed Seff =60%, 80% and 100%) were acquired. Data analysis included semi-quantitative evaluation of image quality of the 4D flow magnitude images (image quality grading on a four point scale), 3D segmentation of the thoracic aorta, and voxel-by-voxel comparisons of systolic 3D flow velocity vector fields between scans. Results Conventional navigator gating resulted in variable Seff = 74±13% (range = 56% – 100%) due to inter-individual variability of respiration patterns. For scans 2–4, the the new navigator implementation was able to achieve predictable total scan times with stable Seff, only depending on heart rate. Semi- and fully quantitative analysis of image quality in 4D flow magnitude images was similar for the new navigator scheme compared to conventional navigator gating. For aortic systolic 3D velocities, good agreement was found between all new navigator settings (scan 2–4) with the conventional navigator gating (scan 1) with best performance for Seff = 80% (mean difference = −0.01; limits od agreement = 0.23, Pearson’s ρ=0.89, p <0.001). No significant differences for image quality or 3D systolic velocities were found for 1.5T compared to 3T. Conclusions The findings of this study demonstrate the

  14. Impact of incorporating visual biofeedback in 4D MRI.

    PubMed

    To, David T; Kim, Joshua P; Price, Ryan G; Chetty, Indrin J; Glide-Hurst, Carri K

    2016-05-08

    Precise radiation therapy (RT) for abdominal lesions is complicated by respiratory motion and suboptimal soft tissue contrast in 4D CT. 4D MRI offers improved con-trast although long scan times and irregular breathing patterns can be limiting. To address this, visual biofeedback (VBF) was introduced into 4D MRI. Ten volunteers were consented to an IRB-approved protocol. Prospective respiratory-triggered, T2-weighted, coronal 4D MRIs were acquired on an open 1.0T MR-SIM. VBF was integrated using an MR-compatible interactive breath-hold control system. Subjects visually monitored their breathing patterns to stay within predetermined tolerances. 4D MRIs were acquired with and without VBF for 2- and 8-phase acquisitions. Normalized respiratory waveforms were evaluated for scan time, duty cycle (programmed/acquisition time), breathing period, and breathing regularity (end-inhale coefficient of variation, EI-COV). Three reviewers performed image quality assessment to compare artifacts with and without VBF. Respiration-induced liver motion was calculated via centroid difference analysis of end-exhale (EE) and EI liver contours. Incorporating VBF reduced 2-phase acquisition time (4.7 ± 1.0 and 5.4 ± 1.5 min with and without VBF, respectively) while reducing EI-COV by 43.8% ± 16.6%. For 8-phase acquisitions, VBF reduced acquisition time by 1.9 ± 1.6 min and EI-COVs by 38.8% ± 25.7% despite breathing rate remaining similar (11.1 ± 3.8 breaths/min with vs. 10.5 ± 2.9 without). Using VBF yielded higher duty cycles than unguided free breathing (34.4% ± 5.8% vs. 28.1% ± 6.6%, respectively). Image grading showed that out of 40 paired evaluations, 20 cases had equivalent and 17 had improved image quality scores with VBF, particularly for mid-exhale and EI. Increased liver excursion was observed with VBF, where superior-inferior, anterior-posterior, and left-right EE-EI displacements were 14.1± 5.8, 4.9 ± 2.1, and 1.5 ± 1.0 mm, respectively, with VBF compared to 11.9

  15. 4D CT sorting based on patient internal anatomy

    NASA Astrophysics Data System (ADS)

    Li, Ruijiang; Lewis, John H.; Cerviño, Laura I.; Jiang, Steve B.

    2009-08-01

    Respiratory motion during free-breathing computed tomography (CT) scan may cause significant errors in target definition for tumors in the thorax and upper abdomen. A four-dimensional (4D) CT technique has been widely used for treatment simulation of thoracic and abdominal cancer radiotherapy. The current 4D CT techniques require retrospective sorting of the reconstructed CT slices oversampled at the same couch position. Most sorting methods depend on external surrogates of respiratory motion recorded by extra instruments. However, respiratory signals obtained from these external surrogates may not always accurately represent the internal target motion, especially when irregular breathing patterns occur. We have proposed a new sorting method based on multiple internal anatomical features for multi-slice CT scan acquired in the cine mode. Four features are analyzed in this study, including the air content, lung area, lung density and body area. We use a measure called spatial coherence to select the optimal internal feature at each couch position and to generate the respiratory signals for 4D CT sorting. The proposed method has been evaluated for ten cancer patients (eight with thoracic cancer and two with abdominal cancer). For nine patients, the respiratory signals generated from the combined internal features are well correlated to those from external surrogates recorded by the real-time position management (RPM) system (average correlation: 0.95 ± 0.02), which is better than any individual internal measures at 95% confidence level. For these nine patients, the 4D CT images sorted by the combined internal features are almost identical to those sorted by the RPM signal. For one patient with an irregular breathing pattern, the respiratory signals given by the combined internal features do not correlate well with those from RPM (correlation: 0.68 ± 0.42). In this case, the 4D CT image sorted by our method presents fewer artifacts than that from the RPM signal. Our

  16. Simple Coupling of Reactor Physics Effects and Uncertain Nuances

    SciTech Connect

    Bays, Samuel

    2012-08-27

    The "Simple Coupling of Reactor Physics Effects and Uncertain Nuances" (SCORPEUN) code is a simple r-z 1-group neutron diffusion code where each r-mesh is coupled to a single-flow-channel model that represents all flow-channels in that r-mesh. This 1-D model assesses q=m*Cp*deletaT for each z-mesh in that channel. This flow channel model is then coupled to a simple 1-D heat conduction model for ascertaining the peak center-line fuel temperature in a hypothetical pin assigned to that flow channel. The code has property lookup capability for water, Na, Zirc, HT9, metalic fuel, oxide fuel, etc. It has linear interpolation features for micro-scopic cross-sections with respect to coolant density and fuel temperature. ***This last feature has not been fully tested and may need development***. The interpolated microscopic cross-sections are then combined (using the water density from the T/H calculation) to generate macroscopic diffusion coefficient, removal cross-section and nu-sigmaF for each r-z mesh of the neutron diffusion code.

  17. Desired Change in Couples: Gender Differences and Effects on Communication

    PubMed Central

    Heyman, Richard E.; Hunt, Ashley N.; Malik, Jill; Smith Slep, Amy M.

    2009-01-01

    Using a sample (N = 453) drawn from a representative sampling frame of couples who are married or living together and have a 3–7 year old child, this study investigates (a) the amount and specific areas of change desired by men and women, (b) the relation between relationship adjustment and desired change; and (c) the ways in which partners negotiate change. On the Areas of Change Questionnaire, women, compared with men, wanted greater increases in their partners’ emotional and companionate behaviors, instrumental support, and parenting involvement; men wanted greater increases in sex. Using the Actor-Partner Interdependence Model (Kenny, 1996, both men’s and women’s relationship adjustment predicted desired change (i.e., actor effects), over and above the effects of their partners’ adjustment (i.e., partner effects); partner effects were not significant. Each couple was also observed discussing the man’s and the woman’s top desired change area. Both men and women behaved more positively during the partner-initiated conversations than during their own-initiated conversations. Women, compared with men, were more negative in their own and in their partners’ conversations. PMID:19685983

  18. Desired change in couples: gender differences and effects on communication.

    PubMed

    Heyman, Richard E; Hunt-Martorano, Ashley N; Malik, Jill; Slep, Amy M Smith

    2009-08-01

    Using a sample (N = 453) drawn from a representative sampling frame of couples who are married or living together and have a 3 to 7 year-old child, this study investigates (a) the amount and specific areas of change desired by men and women, (b) the relation between relationship adjustment and desired change; and (c) the ways in which partners negotiate change. On the Areas of Change Questionnaire, women compared with men, wanted greater increases in their partners' emotional and companionate behaviors, instrumental support, and parenting involvement; men wanted greater increases in sex. Using the Actor-Partner Interdependence Model (Kenny, 1996), both men's and women's relationship adjustment predicted desired change (i.e., actor effects), over and above the effects of their partners' adjustment (i.e., partner effects); partner effects were not significant. Each couple was also observed discussing the man's and the woman's top desired change area. Both men and women behaved more positively during the partner-initiated conversations than during their own-initiated conversations. Women, compared with men, were more negative in their own and in their partners' conversations.

  19. Effective interaction and condensation of dipolaritons in coupled quantum wells

    NASA Astrophysics Data System (ADS)

    Byrnes, Tim; Kolmakov, German V.; Kezerashvili, Roman Ya.; Yamamoto, Yoshihisa

    2014-09-01

    Dipolaritons are a three-way superposition of a photon, a direct exciton, and an indirect exciton that are formed in coupled quantum well microcavities. As is the case with exciton-polaritons, dipolaritons have a self-interaction due to direct and exchange effects of the underlying electrons and holes. Here we present a theoretical description of dipolaritons and derive simple formulas for their basic parameters. In particular, we derive the effective dipolariton-dipolariton interaction taking into account exchange effects between the excitons. We obtain a simple relation to describe the effective interaction at low densities. We find that dipolaritons should condense under suitable conditions, described by a dissipative Gross-Pitaevskii equation. While the parameters for condensation are promising, we find that the level of tunability of the interactions is limited.

  20. Cytotoxic effect of galvanically coupled magnesium-titanium particles.

    PubMed

    Kim, Jua; Gilbert, Jeremy L

    2016-01-01

    Recent work has shown that reduction reactions at metallic biomaterial surfaces can induce significant killing of cells in proximity to the surface. To exploit this phenomenon for therapeutic purposes, for example, for cancer tumor killing or antibacterial effects (amongst other applications), magnesium metal particles, galvanically coupled to titanium by sputtering, have been evaluated for their cell-killing capability (i.e. cytotoxicity). Magnesium (Mg) particles large enough to prevent particle phagocytosis were investigated, so that only electrochemical reactions, and not particle toxicity per se, caused cytotoxic effects. Titanium (Ti) coated magnesium particles, as well as magnesium-only particles were introduced into MC3T3-E1 mouse pre-osteoblast cell cultures over a range of particle concentrations, and cells were observed to die in a dosage-dependent manner. Ti-coated magnesium particles killed more cells at lower particle concentration than magnesium alone (P<0.05), although the pH measured for magnesium and magnesium-titanium had no significant difference at similar particle concentrations. Complete cell killing occurred at 750μg/ml and 1500μg/ml for Mg-Ti and Mg, respectively. Thus, this work demonstrates that galvanically coupled Mg-Ti particles have a significant cell killing capability greater than Mg alone. In addition, when the pH associated with complete killing with particles was created using NaOH only (no particles), then the percentage of cells killed was significantly less (P<0.05). Together, these findings show that pH is not the sole factor associated with cell killing and that the electrochemical reactions, including the reduction reactions, play an important role. Reduction reactions on galvanically coupled Mg-Ti and Mg particles may generate reactive oxygen intermediates that are able to kill cells in close proximity to the particles and this approach may lead to potential therapies for infection and cancer. This paper demonstrates

  1. Meta-analysis of digit ratio 2D:4D shows greater sex difference in the right hand.

    PubMed

    Hönekopp, Johannes; Watson, Steven

    2010-01-01

    Our aims are, first, to describe the sex difference in the length ratio of the second and fourth digits (2D:4D), which likely reflects prenatal testosterone levels in humans. Second, to infer the loss of reliability observed in 2D:4D based on self-measured finger lengths. We used random-effects meta-analysis of 2D:4D based on expert-measured finger lengths (116 samples with 13,260 females and 11,789 males). We find a moderate sex difference (with lower 2D:4D for males), which shows substantial heterogeneity (which is unrelated to age). The sex difference is moderated by the type of finger length measurement and by hand. Measurement involving the distortion of soft tissue leads to a significantly larger sex difference than finger length measurement avoiding this. The sex difference in 2D:4D is larger in the right hand than in the left. The reliability of self-measured 2D:4D in the BBC internet study, by far the largest study on 2D:4D, is estimated to be 46% of that of expert-measured 2D:4D. Right-hand 2D:4D might be a better indicator of prenatal androgenisation than left-hand 2D:4D. The view that 2D:4D has allometric properties (Kratochvil L, Flegr J. 2009. Differences in 2nd to 4th digit length ratio in humans reflect shifts along the common allometric line. Biol Lett 5:643-646.) is not supported. Bone lengths contribute to the sex difference in 2D:4D. In addition, there might be a sex difference in fingers' soft tissue, which should be investigated. Because of measurement unreliability, correlations between 2D:4D and variables of interest are about one-third smaller in the BBC internet study than in studies in which 2D:4D is based on expert-measured finger lengths. (c) 2010 Wiley-Liss, Inc.

  2. 4D embryonic cardiography using gated optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Jenkins, M. W.; Rothenberg, F.; Roy, D.; Nikolski, V. P.; Hu, Z.; Watanabe, M.; Wilson, D. L.; Efimov, I. R.; Rollins, A. M.

    2006-01-01

    Simultaneous imaging of very early embryonic heart structure and function has technical limitations of spatial and temporal resolution. We have developed a gated technique using optical coherence tomography (OCT) that can rapidly image beating embryonic hearts in four-dimensions (4D), at high spatial resolution (10-15 μm), and with a depth penetration of 1.5 - 2.0 mm that is suitable for the study of early embryonic hearts. We acquired data from paced, excised, embryonic chicken and mouse hearts using gated sampling and employed image processing techniques to visualize the hearts in 4D and measure physiologic parameters such as cardiac volume, ejection fraction, and wall thickness. This technique is being developed to longitudinally investigate the physiology of intact embryonic hearts and events that lead to congenital heart defects.

  3. Intelligent Vehicle Systems: A 4D/RCS Approach

    SciTech Connect

    Madhavan, Raj

    2007-04-01

    This book presents new research on autonomous mobility capabilities and shows how technological advances can be anticipated in the coming two decades. An in-depth description is presented on the theoretical foundations and engineering approaches that enable these capabilities. Chapter 1 provides a brief introduction to the 4D/RCS reference model architecture and design methodology that has proven successful in guiding the development of autonomous mobility systems. Chapters 2 through 7 provide more detailed descriptions of research that has been conducted and algorithms that have been developed to implement the various aspects of the 4D/RCS reference model architecture and design methodology. Chapters 8 and 9 discuss applications, performance measures, and standards. Chapter 10 provides a history of Army and DARPA research in autonomous ground mobility. Chapter 11 provides a perspective on the potential future developments in autonomous mobility.

  4. A new spin foam model for 4D gravity

    NASA Astrophysics Data System (ADS)

    Freidel, Laurent; Krasnov, Kirill

    2008-06-01

    Starting from Plebanski formulation of gravity as a constrained BF theory we propose a new spin foam model for 4D Riemannian quantum gravity that generalizes the well-known Barrett Crane model and resolves the inherent to it ultra-locality problem. The BF formulation of 4D gravity possesses two sectors: gravitational and topological ones. The model presented here is shown to give a quantization of the gravitational sector, and is dual to the recently proposed spin foam model of Engle et al which, we show, corresponds to the topological sector. Our methods allow us to introduce the Immirzi parameter into the framework of spin foam quantization. We generalize some of our considerations to the Lorentzian setting and obtain a new spin foam model in that context as well.

  5. Brain tissue segmentation in 4D CT using voxel classification

    NASA Astrophysics Data System (ADS)

    van den Boom, R.; Oei, M. T. H.; Lafebre, S.; Oostveen, L. J.; Meijer, F. J. A.; Steens, S. C. A.; Prokop, M.; van Ginneken, B.; Manniesing, R.

    2012-02-01

    A method is proposed to segment anatomical regions of the brain from 4D computer tomography (CT) patient data. The method consists of a three step voxel classification scheme, each step focusing on structures that are increasingly difficult to segment. The first step classifies air and bone, the second step classifies vessels and the third step classifies white matter, gray matter and cerebrospinal fluid. As features the time averaged intensity value and the temporal intensity change value were used. In each step, a k-Nearest-Neighbor classifier was used to classify the voxels. Training data was obtained by placing regions of interest in reconstructed 3D image data. The method has been applied to ten 4D CT cerebral patient data. A leave-one-out experiment showed consistent and accurate segmentation results.

  6. Quantication and analysis of respiratory motion from 4D MRI

    NASA Astrophysics Data System (ADS)

    Aizzuddin Abd Rahni, Ashrani; Lewis, Emma; Wells, Kevin

    2014-11-01

    It is well known that respiratory motion affects image acquisition and also external beam radiotherapy (EBRT) treatment planning and delivery. However often the existing approaches for respiratory motion management are based on a generic view of respiratory motion such as the general movement of organ, tissue or fiducials. This paper thus aims to present a more in depth analysis of respiratory motion based on 4D MRI for further integration into motion correction in image acquisition or image based EBRT. Internal and external motion was first analysed separately, on a per-organ basis for internal motion. Principal component analysis (PCA) was then performed on the internal and external motion vectors separately and the relationship between the two PCA spaces was analysed. The motion extracted from 4D MRI on general was found to be consistent with what has been reported in literature.

  7. Biomarker correlations of urinary 2,4-D levels in foresters: genomic instability and endocrine disruption.

    PubMed Central

    Garry, V F; Tarone, R E; Kirsch, I R; Abdallah, J M; Lombardi, D P; Long, L K; Burroughs, B L; Barr, D B; Kesner, J S

    2001-01-01

    Forest pesticide applicators constitute a unique pesticide use group. Aerial, mechanical-ground, and focal weed control by application of herbicides, in particular chlorophenoxy herbicides, yield diverse exposure scenarios. In the present work, we analyzed aberrations in G-banded chromosomes, reproductive hormone levels, and polymerase chain reaction-based V(D)J rearrangement frequencies in applicators whose exposures were mostly limited to chlorophenoxy herbicides. Data from appliers where chlorophenoxy use was less frequent were also examined. The biomarker outcome data were compared to urinary levels of 2,4-dichlorophenoxyacetic acid (2,4-D) obtained at the time of maximum 2,4-D use. Further comparisons of outcome data were made to the total volume of herbicides applied during the entire pesticide-use season.Twenty-four applicators and 15 minimally exposed foresters (control) subjects were studied. Categorized by applicator method, men who used a hand-held, backpack sprayer in their applications showed the highest average level (453.6 ppb) of 2,4-D in urine. Serum luteinizing hormone (LH) values were correlated with urinary 2,4-D levels, but follicle-stimulating hormone and free and total testosterone were not. At the height of the application season; 6/7 backpack sprayers, 3/4 applicators who used multinozzle mechanical (boom) sprayers, 4/8 aerial applicators, and 2/5 skidder-radiarc (closed cab) appliers had two or more V(D)J region rearrangements per microgram of DNA. Only 5 of 15 minimally exposed (control) foresters had two or more rearrangements, and 3 of these 5 subjects demonstrated detectable levels of 2,4-D in the urine. Only 8/24 DNA samples obtained from the exposed group 10 months or more after their last chlorophenoxy use had two rearrangements per microgram of DNA, suggesting that the exposure-related effects observed were reversible and temporary. Although urinary 2,4-D levels were not correlated with chromosome aberration frequency, chromosome

  8. Real-time 4D ultrasound mosaicing and visualization.

    PubMed

    Brattain, Laura J; Howe, Robert D

    2011-01-01

    Intra-cardiac 3D ultrasound imaging has enabled new minimally invasive procedures. Its narrow field of view, however, limits its efficacy in guiding beating heart procedures where geometrically complex and spatially extended moving anatomic structures are often involved. In this paper, we present a system that performs electrocardiograph gated 4D mosaicing and visualization of 3DUS volumes. Real-time operation is enabled by GPU implementation. The method is validated on phantom and porcine heart data.

  9. Analysis of 4D Var Data Assimilation Application Issues

    NASA Astrophysics Data System (ADS)

    Trailovic, L.; Etherton, B.; Harrop, C.; Govett, M.

    2016-12-01

    This paper summarizes the challenges encountered with our ongoing development and use of a software system designed to facilitate exploration of computational optimizations and strategies for Data Assimilation (DA). The software system is designed and constructed from scratch using modern software development methods and tools, though it incorporates components of pre-existing systems where appropriate. We present results of experiments that employ this system to test approaches for assimilation of observations using a four-dimensional variational (4D Var) scheme. We propose a modular DA system software architecture and demonstrate its utility using a set of models of varying realism and complexity. The software system design and implementation was initially tested and validated using a simple chaotic atmospheric model. A Quasi-Geostrophic (QG) atmospheric model was used to conduct DA experiments of increased difficulty and to validate the software design at larger scales of model complexity. Our QG DA study focused on 2016 winter weather data where a Nature run was used to represent the "true" state of the atmosphere and observations, whereas observation error covariance and observation operator were adapted from pre-existing DA systems. To increase performance, a parallel-in-time algorithm was applied to solve the proposed 4D Var data assimilation problem. That is, the assimilation window was divided into multiple sub-intervals, which allowed for parallelization of the cost function and gradient computations. Continuity equations of the solution were added as constraints across interval boundaries. This approach produced a different formulation of the variational data assimilation problem than weakly constrained 4D Var. We explored a combination of serial and parallel 4D Var algorithms to increase performance.

  10. Digital-micromirror-device-based confocal 4D microscopy

    NASA Astrophysics Data System (ADS)

    Schellenberg, M.; Kloster, M.; Napier, J.; Peev, E.; Neu, W.

    2012-03-01

    Digital Micromirror Device based microscopy combines fast confocal 4D-microscopy along with conventional methods for light microscopy and new technological approaches to a versatile tool for the observation of in vivo processes in living biological cells and measurement of technical surfaces. Due to the use of variable size pinholes and adjustable scan patterns conditions for confocal measurement can easily be optimized to the prerequisites of the sample "on the fly".

  11. 4D flow cardiovascular magnetic resonance consensus statement.

    PubMed

    Dyverfeldt, Petter; Bissell, Malenka; Barker, Alex J; Bolger, Ann F; Carlhäll, Carl-Johan; Ebbers, Tino; Francios, Christopher J; Frydrychowicz, Alex; Geiger, Julia; Giese, Daniel; Hope, Michael D; Kilner, Philip J; Kozerke, Sebastian; Myerson, Saul; Neubauer, Stefan; Wieben, Oliver; Markl, Michael

    2015-08-10

    Pulsatile blood flow through the cavities of the heart and great vessels is time-varying and multidirectional. Access to all regions, phases and directions of cardiovascular flows has formerly been limited. Four-dimensional (4D) flow cardiovascular magnetic resonance (CMR) has enabled more comprehensive access to such flows, with typical spatial resolution of 1.5×1.5×1.5 - 3×3×3 mm(3), typical temporal resolution of 30-40 ms, and acquisition times in the order of 5 to 25 min. This consensus paper is the work of physicists, physicians and biomedical engineers, active in the development and implementation of 4D Flow CMR, who have repeatedly met to share experience and ideas. The paper aims to assist understanding of acquisition and analysis methods, and their potential clinical applications with a focus on the heart and greater vessels. We describe that 4D Flow CMR can be clinically advantageous because placement of a single acquisition volume is straightforward and enables flow through any plane across it to be calculated retrospectively and with good accuracy. We also specify research and development goals that have yet to be satisfactorily achieved. Derived flow parameters, generally needing further development or validation for clinical use, include measurements of wall shear stress, pressure difference, turbulent kinetic energy, and intracardiac flow components. The dependence of measurement accuracy on acquisition parameters is considered, as are the uses of different visualization strategies for appropriate representation of time-varying multidirectional flow fields. Finally, we offer suggestions for more consistent, user-friendly implementation of 4D Flow CMR acquisition and data handling with a view to multicenter studies and more widespread adoption of the approach in routine clinical investigations.

  12. Repairing Stevenson's step in the 4d Ising model

    NASA Astrophysics Data System (ADS)

    Balog, Janos; Niedermayer, Ferenc; Weisz, Peter

    2006-05-01

    In a recent paper Stevenson claimed that analysis of the data on the wave function renormalization constant near the critical point of the 4d Ising model is not consistent with analytical expectations. Here we present data with improved statistics and show that the results are indeed consistent with conventional wisdom once one takes into account the uncertainty of lattice artifacts in the analytical computations.

  13. Antibody Blockade of Semaphorin 4D Promotes Immune Infiltration into Tumor and Enhances Response to Other Immunomodulatory Therapies.

    PubMed

    Evans, Elizabeth E; Jonason, Alan S; Bussler, Holm; Torno, Sebold; Veeraraghavan, Janaki; Reilly, Christine; Doherty, Michael A; Seils, Jennifer; Winter, Laurie A; Mallow, Crystal; Kirk, Renee; Howell, Alan; Giralico, Susan; Scrivens, Maria; Klimatcheva, Katya; Fisher, Terrence L; Bowers, William J; Paris, Mark; Smith, Ernest S; Zauderer, Maurice

    2015-06-01

    Semaphorin 4D (SEMA4D, CD100) and its receptor plexin-B1 (PLXNB1) are broadly expressed in murine and human tumors, and their expression has been shown to correlate with invasive disease in several human tumors. SEMA4D normally functions to regulate the motility and differentiation of multiple cell types, including those of the immune, vascular, and nervous systems. In the setting of cancer, SEMA4D-PLXNB1 interactions have been reported to affect vascular stabilization and transactivation of ERBB2, but effects on immune-cell trafficking in the tumor microenvironment (TME) have not been investigated. We describe a novel immunomodulatory function of SEMA4D, whereby strong expression of SEMA4D at the invasive margins of actively growing tumors influences the infiltration and distribution of leukocytes in the TME. Antibody neutralization of SEMA4D disrupts this gradient of expression, enhances recruitment of activated monocytes and lymphocytes into the tumor, and shifts the balance of cells and cytokines toward a proinflammatory and antitumor milieu within the TME. This orchestrated change in the tumor architecture was associated with durable tumor rejection in murine Colon26 and ERBB2(+) mammary carcinoma models. The immunomodulatory activity of anti-SEMA4D antibody can be enhanced by combination with other immunotherapies, including immune checkpoint inhibition and chemotherapy. Strikingly, the combination of anti-SEMA4D antibody with antibody to CTLA-4 acts synergistically to promote complete tumor rejection and survival. Inhibition of SEMA4D represents a novel mechanism and therapeutic strategy to promote functional immune infiltration into the TME and inhibit tumor progression.

  14. 4D-Flow validation, numerical and experimental framework

    NASA Astrophysics Data System (ADS)

    Sansom, Kurt; Liu, Haining; Canton, Gador; Aliseda, Alberto; Yuan, Chun

    2015-11-01

    This work presents a group of assessment metrics of new 4D MRI flow sequences, an imaging modality that allows for visualization of three-dimensional pulsatile flow in the cardiovascular anatomy through time-resolved three-dimensional blood velocity measurements from cardiac-cycle synchronized MRI acquisition. This is a promising tool for clinical assessment but lacks a robust validation framework. First, 4D-MRI flow in a subject's stenotic carotid bifurcation is compared with a patient-specific CFD model using two different boundary condition methods. Second, Particle Image Velocimetry in a patient-specific phantom is used as a benchmark to compare the 4D-MRI in vivo measurements and CFD simulations under the same conditions. Comparison of estimated and measureable flow parameters such as wall shear stress, fluctuating velocity rms, Lagrangian particle residence time, will be discussed, with justification for their biomechanics relevance and the insights they can provide on the pathophysiology of arterial disease: atherosclerosis and intimal hyperplasia. Lastly, the framework is applied to a new sequence to provide a quantitative assessment. A parametric analysis on the carotid bifurcation pulsatile flow conditions will be presented and an accuracy assessment provided.

  15. 2D:4D Ratio and its Implications in Medicine

    PubMed Central

    Jeevanandam, Saravanakumar

    2016-01-01

    Digit ratios, especially 2D:4D ratio, a potential proxy marker for prenatal androgen exposure shows sexual dimorphism. Existing literature and recent research show accumulating evidence on 2D:4D ratio showing correlations with various phenotypic traits in humans. Ratio of 2D:4D is found to correlate negatively to testosterone and positively to oestrogen in the foetus. Interestingly, it is constant since birth and not influenced by the adult hormone levels. Usually, males have lower ratios when compared to females. Prenatal androgen exposure and therefore, digit ratios have been reported to be associated with numerical competencies, spatial skills, handedness, cognitive abilities, academic performance, sperm counts, personalities and prevalence of obesity, migraine, eating disorders, depression, myopia, autism etc. The authors have attempted to write a brief account on the digit ratios and the dimorphism observed in various physiological, psychological and behavioural traits. Also, the authors have discussed the relevant molecular basics and the methods of measurement of digit ratios. PMID:28208851

  16. Transverse-longitudinal coupling effect in laser bunch slicing.

    PubMed

    Shimada, M; Katoh, M; Adachi, M; Tanikawa, T; Kimura, S; Hosaka, M; Yamamoto, N; Takashima, Y; Takahashi, T

    2009-10-02

    We report turn-by-turn observation of coherent synchrotron radiation (CSR) produced by the laser bunch slicing technique at an electron storage ring operated with a small momentum compaction factor. CSR emission was intermittent, and its interval depended strongly on the betatron tune. This peculiar behavior of the CSR could be interpreted as a result of coupling between the transverse and longitudinal motion of the electrons. This is the first observation of such an effect, which would be important not only for controlling the CSR emission but also for generating and transporting ultrashort electron bunches or electron bunches with microdensity structures in advanced accelerators.

  17. Effective Hamiltonian for non-minimally coupled scalar fields

    NASA Astrophysics Data System (ADS)

    Meşe, Emine; Pirinççiog˜Lu, Nurettin; Açıkgöz, Irfan; Binbay, Figen

    2009-01-01

    In the post Newtonian limit, a non-relativistic Hamiltonian is derived for scalar fields with quartic self-interaction and non-minimal coupling to the curvature scalar of the background spacetime. These effects are found to contribute to the non-relativistic Hamiltonian by adding nonlinearities and by modifying the gravitational Darwin term. As we discuss briefly in the text, the impact of these novel structures can be sizable in dense media like neutron star core, and can have observable signatures in phase transitions, for example.

  18. Spin-orbit coupling induced by effective mass gradient

    NASA Astrophysics Data System (ADS)

    Matos-Abiague, A.

    2010-04-01

    The existence of a spin-orbit coupling (SOC) induced by the gradient of the effective mass in low-dimensional heterostructures is revealed. In structurally asymmetric quasi-two-dimensional semiconductor heterostructures the presence of a mass gradient across the interfaces results in a SOC which competes with the SOC created by the electric field in the valence band. However, in graded quantum wells subjected to an external electric field, the mass-gradient-induced SOC can be finite even when the electric field in the valence band vanishes.

  19. Can exposure to prenatal sex hormones (2D:4D) predict cognitive reflection?

    PubMed

    Bosch-Domènech, Antoni; Brañas-Garza, Pablo; Espín, Antonio M

    2014-05-01

    The Cognitive Reflection Test (CRT) is a test introduced by Frederick (2005). The task is designed to measure the tendency to override an intuitive response that is incorrect and to engage in further reflection that leads to the correct response. The consistent sex differences in CRT performance may suggest a role for prenatal sex hormones. A now widely studied putative marker for relative prenatal testosterone is the second-to-fourth digit ratio (2D:4D). This paper tests to what extent 2D:4D, as a proxy for the prenatal ratio of testosterone/estrogens, can predict CRT scores in a sample of 623 students. After controlling for sex, we observe that a lower 2D:4D (reflecting a relative higher exposure to testosterone) is significantly associated with a higher number of correct answers. The result holds for both hands' 2D:4Ds. In addition, the effect appears to be stronger for females than for males. We also control for patience and math proficiency, which are significantly related to performance in the CRT. But the effect of 2D:4D on performance in CRT is not reduced with these controls, implying that these variables are not mediating the relationship between digit ratio and CRT. Copyright © 2014 The Authors. Published by Elsevier Ltd. All rights reserved.

  20. A method for deriving a 4D-interpolated balanced planning target for mobile tumor radiotherapy

    SciTech Connect

    Roland, Teboh; Hales, Russell; McNutt, Todd; Wong, John; Simari, Patricio; Tryggestad, Erik

    2012-01-15

    Purpose: Tumor control and normal tissue toxicity are strongly correlated to the tumor and normal tissue volumes receiving high prescribed dose levels in the course of radiotherapy. Planning target definition is, therefore, crucial to ensure favorable clinical outcomes. This is especially important for stereotactic body radiation therapy of lung cancers, characterized by high fractional doses and steep dose gradients. The shift in recent years from population-based to patient-specific treatment margins, as facilitated by the emergence of 4D medical imaging capabilities, is a major improvement. The commonly used motion-encompassing, or internal-target volume (ITV), target definition approach provides a high likelihood of coverage for the mobile tumor but inevitably exposes healthy tissue to high prescribed dose levels. The goal of this work was to generate an interpolated balanced planning target that takes into account both tumor coverage and normal tissue sparing from high prescribed dose levels, thereby improving on the ITV approach. Methods: For each 4DCT dataset, 4D deformable image registration was used to derive two bounding targets, namely, a 4D-intersection and a 4D-composite target which minimized normal tissue exposure to high prescribed dose levels and maximized tumor coverage, respectively. Through definition of an ''effective overlap volume histogram'' the authors derived an ''interpolated balanced planning target'' intended to balance normal tissue sparing from prescribed doses with tumor coverage. To demonstrate the dosimetric efficacy of the interpolated balanced planning target, the authors performed 4D treatment planning based on deformable image registration of 4D-CT data for five previously treated lung cancer patients. Two 4D plans were generated per patient, one based on the interpolated balanced planning target and the other based on the conventional ITV target. Plans were compared for tumor coverage and the degree of normal tissue sparing

  1. Genome constraint through sexual reproduction: application of 4D-Genomics in reproductive biology.

    PubMed

    Horne, Steven D; Abdallah, Batoul Y; Stevens, Joshua B; Liu, Guo; Ye, Karen J; Bremer, Steven W; Heng, Henry H Q

    2013-06-01

    Assisted reproductive technologies have been used to achieve pregnancies since the first successful test tube baby was born in 1978. Infertile couples are at an increased risk for multiple miscarriages and the application of current protocols are associated with high first-trimester miscarriage rates. Among the contributing factors of these higher rates is a high incidence of fetal aneuploidy. Numerous studies support that protocols including ovulation-induction, sperm cryostorage, density-gradient centrifugation, and embryo culture can induce genome instability, but the general mechanism is less clear. Application of the genome theory and 4D-Genomics recently led to the establishment of a new paradigm for sexual reproduction; sex primarily constrains genome integrity that defines the biological system rather than just providing genetic diversity at the gene level. We therefore propose that application of assisted reproductive technologies can bypass this sexual reproduction filter as well as potentially induce additional system instability. We have previously demonstrated that a single-cell resolution genomic approach, such as spectral karyotyping to trace stochastic genome level alterations, is effective for pre- and post-natal analysis. We propose that monitoring overall genome alteration at the karyotype level alongside the application of assisted reproductive technologies will improve the efficacy of the techniques while limiting stress-induced genome instability. The development of more single-cell based cytogenomic technologies are needed in order to better understand the system dynamics associated with infertility and the potential impact that assisted reproductive technologies have on genome instability. Importantly, this approach will be useful in studying the potential for diseases to arise as a result of bypassing the filter of sexual reproduction.

  2. Exchange bias training effect in coupled all ferromagnetic bilayer structures

    NASA Astrophysics Data System (ADS)

    Polisetty, Srinivas; He, Xi; Binek, Christian; Berger, Andreas

    2006-03-01

    We study exchange coupled bilayers of soft and hard ferromagnetic (FM) thin films by means of Alternating Gradient Force Magnetometry. A CoCr thin film realizes the magnetically soft layer (SL) which is exchange coupled via a Ru-interlayer with a hard CoPtCrB pinning layer (HL). This new class of all FM bilayers shows remarkable analogies to conventional antiferromagnetic (AF)/FM exchange bias (EB) heterostructures. Not only do these all FM bilayers exhibit a tunable EB effect, they also show a distinct training behavior upon cycling the SL through consecutive hysteresis loops. Training resembles the cycle dependent evolution of the bias field and is to a large extend analogous to the gradual degradation of the EB field observed upon cycling the FM top layer of a AF/FM EB heterostructure through consecutive hysteresis loops. However, in contrast to these conventional EB systems, our all FM bilayer structures allow the observation of training induced changes in the bias-setting HL by means of simple magnetometry. Our experiments show unambiguously that the training effect is driven by deviations from equilibrium in the pinning layer. A comparison of the experimental data with predictions from a theory based upon triggered relaxation phenomena shows excellent agreement.

  3. Co-Authorship and Bibliographic Coupling Network Effects on Citations

    PubMed Central

    Biscaro, Claudio; Giupponi, Carlo

    2014-01-01

    This paper analyzes the effects of the co-authorship and bibliographic coupling networks on the citations received by scientific articles. It expands prior research that limited its focus on the position of co-authors and incorporates the effects of the use of knowledge sources within articles: references. By creating a network on the basis of shared references, we propose a way to understand whether an article bridges among extant strands of literature and infer the size of its research community and its embeddedness. Thus, we map onto the article – our unit of analysis – the metrics of authors' position in the co-authorship network and of the use of knowledge on which the scientific article is grounded. Specifically, we adopt centrality measures – degree, betweenneess, and closeness centrality – in the co-authorship network and degree, betweenness centrality and clustering coefficient in the bibliographic coupling and show their influence on the citations received in first two years after the year of publication. Findings show that authors' degree positively impacts citations. Also closeness centrality has a positive effect manifested only when the giant component is relevant. Author's betweenness centrality has instead a negative effect that persists until the giant component - largest component of the network in which all nodes can be linked by a path - is relevant. Moreover, articles that draw on fragmented strands of literature tend to be cited more, whereas the size of the scientific research community and the embeddedness of the article in a cohesive cluster of literature have no effect. PMID:24911416

  4. Statistical 4D graphs for multi-organ abdominal segmentation from multiphase CT.

    PubMed

    Linguraru, Marius George; Pura, John A; Pamulapati, Vivek; Summers, Ronald M

    2012-05-01

    The interpretation of medical images benefits from anatomical and physiological priors to optimize computer-aided diagnosis applications. Diagnosis also relies on the comprehensive analysis of multiple organs and quantitative measures of soft tissue. An automated method optimized for medical image data is presented for the simultaneous segmentation of four abdominal organs from 4D CT data using graph cuts. Contrast-enhanced CT scans were obtained at two phases: non-contrast and portal venous. Intra-patient data were spatially normalized by non-linear registration. Then 4D convolution using population training information of contrast-enhanced liver, spleen and kidneys was applied to multiphase data to initialize the 4D graph and adapt to patient-specific data. CT enhancement information and constraints on shape, from Parzen windows, and location, from a probabilistic atlas, were input into a new formulation of a 4D graph. Comparative results demonstrate the effects of appearance, enhancement, shape and location on organ segmentation. All four abdominal organs were segmented robustly and accurately with volume overlaps over 93.6% and average surface distances below 1.1mm.

  5. Experimental investigation of irregular motion impact on 4D PET-based particle therapy monitoring

    NASA Astrophysics Data System (ADS)

    Tian, Y.; Stützer, K.; Enghardt, W.; Priegnitz, M.; Helmbrecht, S.; Bert, C.; Fiedler, F.

    2016-01-01

    Particle therapy positron emission tomography (PT-PET) is an in vivo and non-invasive imaging technique to monitor treatment delivery in particle therapy. The inevitable patient respiratory motion during irradiation causes artefacts and inaccurate activity distribution in PET images. Four-dimensional (4D) maximum likelihood expectation maximisation (4D MLEM) allows for a compensation of these effects, but has up to now been restricted to regular motion for PT-PET investigations. However, intra-fractional motion during treatment might differ from that during acquisition of the 4D-planning CT (e.g. amplitude variation, baseline drift) and therefore might induce inaccurate 4D PET reconstruction results. This study investigates the impact of different irregular analytical one-dimensional (1D) motion patterns on PT-PET imaging by means of experiments with a radioactive source and irradiated moving phantoms. Three sorting methods, namely phase sorting, equal amplitude sorting and event-based amplitude sorting, were applied to manage the PET list-mode data. The influence of these sorting methods on the motion compensating algorithm has been analysed. The event-based amplitude sorting showed a superior performance and it is applicable for irregular motions with  ⩽4 mm amplitude elongation and drift. For motion with 10 mm baseline drift, the normalised root mean square error was as high as 10.5% and a 10 mm range deviation was observed.

  6. Statistical 4D Graphs for Multi-Organ Abdominal Segmentation from Multiphase CT

    PubMed Central

    Linguraru, Marius George; Pura, John A.; Pamulapati, Vivek; Summers, Ronald M.

    2012-01-01

    The interpretation of medical images benefits from anatomical and physiological priors to optimize computer-aided diagnosis applications. Diagnosis also relies on the comprehensive analysis of multiple organs and quantitative measures of soft tissue. An automated method optimized for medical image data is presented for the simultaneous segmentation of four abdominal organs from 4D CT data using graph cuts. Contrast-enhanced CT scans were obtained at two phases: non-contrast and portal venous. Intra-patient data were spatially normalized by non-linear registration. Then 4D convolution using population training information of contrast-enhanced liver, spleen and kidneys was applied to multiphase data to initialize the 4D graph and adapt to patient-specific data. CT enhancement information and constraints on shape, from Parzen windows, and location, from a probabilistic atlas, were input into a new formulation of a 4D graph. Comparative results demonstrate the effects of appearance, enhancement, shape and location on organ segmentation. All four abdominal organs were segmented robustly and accurately with volume overlaps over 93.6% and average surface distances below 1.1 mm. PMID:22377657

  7. Using flow feature to extract pulsatile blood flow from 4D flow MRI images

    NASA Astrophysics Data System (ADS)

    Wang, Zhiqiang; Zhao, Ye; Yu, Whitney; Chen, Xi; Lin, Chen; Kralik, Stephen F.; Hutchins, Gary D.

    2017-02-01

    4D flow MRI images make it possible to measure pulsatile blood flow inside deforming vessel, which is critical in accurate blood flow visualization, simulation, and evaluation. Such data has great potential to overcome problems in existing work, which usually does not reflect the dynamic nature of elastic vessels and blood flows in cardiac cycles. However, the 4D flow MRI data is often low-resolution and with strong noise. Due to these challenges, few efforts have been successfully conducted to extract dynamic blood flow fields and deforming artery over cardiac cycles, especially for small artery like carotid. In this paper, a robust flow feature, particularly the mean flow intensity is used to segment blood flow regions inside vessels from 4D flow MRI images in whole cardiac cycle. To estimate this flow feature more accurately, adaptive weights are added to the raw velocity vectors based on the noise strength of MRI imaging. Then, based on this feature, target arteries are tracked in at different time steps in a cardiac cycle. This method is applied to the clinical 4D flow MRI data in neck area. Dynamic vessel walls and blood flows are effectively generated in a cardiac cycle in the relatively small carotid arteries. Good image segmentation results on 2D slices are presented, together with the visualization of 3D arteries and blood flows. Evaluation of the method was performed by clinical doctors and by checking flow volume rates in the vertebral and carotid arteries.

  8. [Degradation of 2, 4-D by combined catalytic dechlorination and biological oxidation].

    PubMed

    Zhou, Hong-yi; Zeng, Si-si; Liang, Si; Han, Jian

    2014-09-01

    In this paper, Pd/Fe nanoparticles were used to degrade 2,4-D. Then the resulted solution of 2,4-D dechlorination was biological oxidized by activated sludge. And the effects of initial pH, activated sludge volume, initial contaminant concentration and temperature on the removal of PA were studied. Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE) was used to study microbial community structure. And High Performance Liquid Chromatography (HPLC) was employed to determine and analyze the degradation process of target pollutant. The conclusions can be summarized as follows: (1) Pd/Fe can degrade 2,4-D efficiently, 2-CPA was the intermediate product, and the end product was PA. (2) Compared with 2,4-D, the dechlorination product PA has lower biological toxicity, and can be more easily degraded by activated sludges. (3) pH = 7, 50 mL activated sludge/200 mL solution, PA initial concentration of 14. 6 mg L-1 and 30°C favored the PA removal. Under suitable conditions, the removal rate of PA can reach to 84. 3% after 96 hours.

  9. Preoperative localization of hyperfunctioning parathyroid glands with 4D-CT.

    PubMed

    Lundstroem, Anke Katrin; Trolle, Waldemar; Soerensen, Christian Hjort; Myschetzky, Peter Sand

    2016-05-01

    Primary hyperparathyroidism (pHPT) is almost exclusively the result of a solitary parathyroid adenoma. In most cases, the affected gland can be surgically removed, but precise preoperative imaging is essential for adenoma localization prior to surgical intervention. In this study, we evaluated the diagnostic value of four-dimensional computed tomography (4D-CT) as a preoperative imaging tool in relation to the localization of pathologic parathyroid glands in patients with pHPT and negative sestamibi scans. This study included 43 consecutive patients with pHPT referred for parathyroidectomy at the Department of Head and Neck Surgery of Copenhagen University Hospital Rigshospitalet in 2011 and 2012. All patients had a 4D-CT performed prior to parathyroidectomy. CT localization of the suspected adenoma was correlated to the actual surgical findings and subsequent histological diagnosis was also available as references for the accuracy of this imaging tool. Hyperfunctioning parathyroid glands were found in 40 patients. 4D-CT identified 32 solitary hyperfunctioning parathyroid glands located on the correct side of the neck (PPV 76 %) and 21 located within the correct quadrant (PPV 49 %). Unilateral resection was performed in 72 % of patients due to the localization findings of preoperative imaging. 4D-CT can, therefore, be considered an effective method for the preoperative localization of parathyroid adenomas and is an important tool in surgical intervention for patients referred to parathyroidectomy.

  10. Experimental investigation of irregular motion impact on 4D PET-based particle therapy monitoring.

    PubMed

    Tian, Y; Stützer, K; Enghardt, W; Priegnitz, M; Helmbrecht, S; Bert, C; Fiedler, F

    2016-01-21

    Particle therapy positron emission tomography (PT-PET) is an in vivo and non-invasive imaging technique to monitor treatment delivery in particle therapy. The inevitable patient respiratory motion during irradiation causes artefacts and inaccurate activity distribution in PET images. Four-dimensional (4D) maximum likelihood expectation maximisation (4D MLEM) allows for a compensation of these effects, but has up to now been restricted to regular motion for PT-PET investigations. However, intra-fractional motion during treatment might differ from that during acquisition of the 4D-planning CT (e.g. amplitude variation, baseline drift) and therefore might induce inaccurate 4D PET reconstruction results. This study investigates the impact of different irregular analytical one-dimensional (1D) motion patterns on PT-PET imaging by means of experiments with a radioactive source and irradiated moving phantoms. Three sorting methods, namely phase sorting, equal amplitude sorting and event-based amplitude sorting, were applied to manage the PET list-mode data. The influence of these sorting methods on the motion compensating algorithm has been analysed. The event-based amplitude sorting showed a superior performance and it is applicable for irregular motions with ⩽ 4 mm amplitude elongation and drift. For motion with 10 mm baseline drift, the normalised root mean square error was as high as 10.5% and a 10 mm range deviation was observed.

  11. Polypyrimidine tract-binding protein induces p19(Ink4d) expression and inhibits the proliferation of H1299 cells.

    PubMed

    Lin, Shankung; Wang, Ming Jen; Tseng, Kuo-Yun

    2013-01-01

    The expression of polypyrimidine tract-binding protein (PTB) is up-regulated in many types of cancer. Here, we studied the role of PTB in the growth of non small cell lung cancer cells. Data showed that PTB overexpression inhibited the growth of H1299 cells at least by inhibiting DNA synthesis. Quantitative real-time PCR and Western blot analyses showed that PTB overexpression in H1299 cells specifically induced the expression of p19(Ink4d), an inhibitor of cyclin-dependent kinase 4. Repression of p19(Ink4d) expression partially rescued PTB-caused proliferation inhibition. PTB overexpression also inhibited the growth and induced the expression of p19(Ink4d) mRNA in A549 cells. However, Western blot analyses failed to detect the presence of p19(Ink4d) protein in A549 cells. To address how PTB induced p19(Ink4d) in H1299 cells, we showed that PTB might up-regulate the activity of p19(Ink4d) gene (CDKN2D) promoter. Besides, PTB lacking the RNA recognition motif 3 (RRM3) was less effective in growth inhibition and p19(Ink4d) induction, suggesting that RNA-binding activity of PTB plays an important role in p19(Ink4d) induction. However, immunoprecipitation of ribonuclearprotein complexes plus quantitative real-time PCR analyses showed that PTB might not bind p19(Ink4d) mRNA, suggesting that PTB overexpression might trigger the other RNA-binding protein(s) to bind p19(Ink4d) mRNA. Subsequently, RNA electrophoretic mobility-shift assays revealed a 300-base segment (designated as B2) within the 3'UTR of p19(Ink4d) mRNA, with which the cytoplasmic lysates of PTB-overexpressing cells formed more prominent complexes than did control cell lysates. Insertion of B2 into a reporter construct increased the expression of the chimeric luciferase transcripts in transfected PTB-overexpressing cells but not in control cells; conversely, overexpression of B2-containing reporter construct in PTB-overexpressing cells abolished the induction of p19(Ink4d) mRNA. In sum, we have shown that

  12. Spin effects in coupled quantum dots under ac electric fields

    NASA Astrophysics Data System (ADS)

    Meza-Montes, Lilia; Hernandez, Arezky H.; Ulloa, Sergio E.

    2007-03-01

    Spin control has recently attracted attention for applications in spin-based devices. Different effects and applied fields have been suggested to accomplish the goal. We explore the time evolution of electronic spin in coupled quantum dots under harmonic electric fields. Using the Floquet formalism, we obtain the time dependent wave function in terms of the Floquet states and the quasi-energy spectrum for a single electron in double InSb dots. The spatial part of the wave function includes the SIA and BIA spin-orbit effects. The spectral force is analyzed at anti-crossings of the quasi-energy bands as a function of the field strength. The resulting dynamical symmetries and the way they reflect in the time evolution of the spin clouds will be discussed.

  13. Exchange bias training effect in coupled all ferromagnetic bilayer structures.

    PubMed

    Binek, Ch; Polisetty, S; He, Xi; Berger, A

    2006-02-17

    Exchange coupled bilayers of soft and hard ferromagnetic thin films show remarkable analogies to conventional antiferromagnetic/ferromagnetic exchange bias heterostructures. Not only do all these ferromagnetic bilayers exhibit a tunable exchange bias effect, they also show a distinct training behavior upon cycling the soft layer through consecutive hysteresis loops. In contrast with conventional exchange bias systems, such all ferromagnetic bilayer structures allow the observation of training induced changes in the bias-setting hardmagnetic layer by means of simple magnetometry. Our experiments show unambiguously that the exchange bias training effect is driven by deviations from equilibrium in the pinning layer. A comparison of our experimental data with predictions from a theory based upon triggered relaxation phenomena shows excellent agreement.

  14. Exchange Bias Training Effect in Coupled All Ferromagnetic Bilayer Structures

    NASA Astrophysics Data System (ADS)

    Binek, Ch.; Polisetty, S.; He, Xi; Berger, A.

    2006-02-01

    Exchange coupled bilayers of soft and hard ferromagnetic thin films show remarkable analogies to conventional antiferromagnetic/ferromagnetic exchange bias heterostructures. Not only do all these ferromagnetic bilayers exhibit a tunable exchange bias effect, they also show a distinct training behavior upon cycling the soft layer through consecutive hysteresis loops. In contrast with conventional exchange bias systems, such all ferromagnetic bilayer structures allow the observation of training induced changes in the bias-setting hardmagnetic layer by means of simple magnetometry. Our experiments show unambiguously that the exchange bias training effect is driven by deviations from equilibrium in the pinning layer. A comparison of our experimental data with predictions from a theory based upon triggered relaxation phenomena shows excellent agreement.

  15. A subordinate status position increases the present value of financial resources for low 2D:4D men.

    PubMed

    Millet, Kobe; Dewitte, Siegfried

    2008-01-01

    It has been suggested that the ratio of the length of the 2nd and 4th fingers (digit ratio or 2D:4D) is related to prenatal testosterone with lower ratios thought to be influenced by higher prenatal testosterone levels. Accordingly, low 2D:4D has been associated to a number of fitness-related factors, such as high status in competitive sports and in music. Recent evidence suggests that 2D:4D is also related to economic decision making. We combine both streams of research in the present paper. In two studies we manipulated status in two different ways. We found that a subordinate position raises discount rates, consistent with the reasoning that the present utility of money is higher for men in this position. Moreover, the effect was more pronounced for men with a low 2D:4D. There was a significant negative relationship between 2D:4D and level of discounting in a subordinate status position, but no significant relationship emerged in the dominant status position. Our studies add evidence to the recent line of research associating digit ratio and economic decision making. Moreover, our studies show that future 2D:4D research should focus on plausible interactions between 2D:4D and context cues rather than on linear relations. (c) 2007 Wiley-Liss, Inc.

  16. Exchange bias training effect in magnetically coupled bilayers

    NASA Astrophysics Data System (ADS)

    Polisetty, Srinivas

    Interfaces in magnetically coupled bilayer heterostructures play a vital role in novel spintronics devices. Particularly, control of the interface spin structure enables the development of progressively down-scalable magnetic read-heads which are of major importance for non volatile magnetic recording media. Exchange bias and its accompanying training effect are fundamental magnetic coupling phenomena taking place at the interfaces of antiferromagnetic/ferromagnetic and hard/soft ferromagnetic bilayers. Here, in my thesis I present the experimental results of exchange bias training in the prototypical antiferromagnetic/ferromagnetic exchange bias system CoO/Co and the corresponding coupling and aging phenomena in the all ferromagnetic hard/soft bilayer CoPtCrB/CoCr. The latter system provides experimental access to its pinning layer magnetization thereby allowing to measure fundamental properties of exchange bias and its corresponding training phenomenon. A phenomenological theory is best fitted to all experimental training data of antiferromagnetic/ferromagnetic and hard/soft ferromagnetic bilayers evidencing the universality of the theory. My studies are further extended to the temperature dependence of the exchange bias training effect. Again, excellent agreement between experiment and theory confirms the remarkable universality of the underlying phenomenological approach. Furthermore, the dependence of the exchange bias training on the ferromagnetic film thickness is investigated in a CoO/Co-wedge sample. Scaling behavior with collapse of the temperature and thickness dependent parameters onto a single master curve is presented. Magnetotransport measurements are used for complementary studies of exchange bias in CoO/Co-heterostructures. Here, exchange bias produces a shift of the magnetoresistance curve along the magnetic field axis and an additional asymmetry along the resistance axis. The dynamic non-equilibrium properties of the exchange bias training effect

  17. No Evidence that 2D:4D is Related to the Number of CAG Repeats in the Androgen Receptor Gene.

    PubMed

    Hönekopp, Johannes

    2013-01-01

    The length ratio of the second to the fourth digit (2D:4D) is a putative marker of prenatal testosterone (T) effects. The number of CAG repeats (CAGn) in the AR gene is negatively correlated with T sensitivity in vitro. Results regarding the relationship between 2D:4D and CAGn are mixed but have featured prominently in arguments for and against the validity of 2D:4D. Here, I present random-effects meta-analyses on 14 relevant samples with altogether 1904 subjects. Results were homogeneous across studies. Even liberal estimates (upper limit of the 95% CI) were close to zero and therefore suggested no substantial relationship of CAGn with either right-hand 2D:4D, left-hand 2D:4D, or the difference between the two. However, closer analysis of the effects of CAGn on T dependent gene activation in vitro and of relationships between CAGn and T dependent phenotypic characteristics suggest that normal variability of CAGn has mostly no, very small, or inconsistent effects. Therefore, the lack of a clear association between CAGn and 2D:4D has no negative implications for the latter's validity as a marker of prenatal T effects.

  18. No Evidence that 2D:4D is Related to the Number of CAG Repeats in the Androgen Receptor Gene

    PubMed Central

    Hönekopp, Johannes

    2013-01-01

    The length ratio of the second to the fourth digit (2D:4D) is a putative marker of prenatal testosterone (T) effects. The number of CAG repeats (CAGn) in the AR gene is negatively correlated with T sensitivity in vitro. Results regarding the relationship between 2D:4D and CAGn are mixed but have featured prominently in arguments for and against the validity of 2D:4D. Here, I present random-effects meta-analyses on 14 relevant samples with altogether 1904 subjects. Results were homogeneous across studies. Even liberal estimates (upper limit of the 95% CI) were close to zero and therefore suggested no substantial relationship of CAGn with either right-hand 2D:4D, left-hand 2D:4D, or the difference between the two. However, closer analysis of the effects of CAGn on T dependent gene activation in vitro and of relationships between CAGn and T dependent phenotypic characteristics suggest that normal variability of CAGn has mostly no, very small, or inconsistent effects. Therefore, the lack of a clear association between CAGn and 2D:4D has no negative implications for the latter’s validity as a marker of prenatal T effects. PMID:24367354

  19. 2D-4D correspondence: Towers of kinks versus towers of monopoles in N=2 theories

    NASA Astrophysics Data System (ADS)

    Bolokhov, Pavel A.; Shifman, Mikhail; Yung, Alexei

    2012-04-01

    We continue to study the BPS spectrum of the N=(2,2) CPN-1 model with the ZN-symmetric twisted mass terms. We focus on analysis of the “extra” towers found previously in [P. A. Bolokhov, M. Shifman, and A. Yung, arXiv:1104.5241], and compare them to the states that can be identified in the quasiclassical domain. Exact analysis of the strong-coupling states shows that not all of them survive when passing to the weak-coupling domain. Some of the states decay on the curves of the marginal stability. Thus, not all strong-coupling states can be analytically continued to weak coupling to match the observable bound states. At weak coupling, we confirm the existence of bound states of topologically charged kinks and elementary quanta. Quantization of the U(1) kink modulus leads to formation of towers of such states. For the ZN-symmetric twisted masses their number is by far less than N-1 as was conjectured previously. We investigate the quasiclassical limit and show that out of N possible towers only two survive in the spectrum for odd N, and a single tower for even N. In the case of CP2 theory the related curves of the marginal stability are discussed in detail. In these points we overlap and completely agree with the results of Dorey and Petunin. We also comment on 2D-4D correspondence.

  20. Fast GPU based adaptive filtering of 4D echocardiography.

    PubMed

    Broxvall, Mathias; Emilsson, Kent; Thunberg, Per

    2012-06-01

    Time resolved three-dimensional (3D) echocardiography generates four-dimensional (3D+time) data sets that bring new possibilities in clinical practice. Image quality of four-dimensional (4D) echocardiography is however regarded as poorer compared to conventional echocardiography where time-resolved 2D imaging is used. Advanced image processing filtering methods can be used to achieve image improvements but to the cost of heavy data processing. The recent development of graphics processing unit (GPUs) enables highly parallel general purpose computations, that considerably reduces the computational time of advanced image filtering methods. In this study multidimensional adaptive filtering of 4D echocardiography was performed using GPUs. Filtering was done using multiple kernels implemented in OpenCL (open computing language) working on multiple subsets of the data. Our results show a substantial speed increase of up to 74 times, resulting in a total filtering time less than 30 s on a common desktop. This implies that advanced adaptive image processing can be accomplished in conjunction with a clinical examination. Since the presented GPU processor method scales linearly with the number of processing elements, we expect it to continue scaling with the expected future increases in number of processing elements. This should be contrasted with the increases in data set sizes in the near future following the further improvements in ultrasound probes and measuring devices. It is concluded that GPUs facilitate the use of demanding adaptive image filtering techniques that in turn enhance 4D echocardiographic data sets. The presented general methodology of implementing parallelism using GPUs is also applicable for other medical modalities that generate multidimensional data.

  1. 4D seismic data acquisition method during coal mining

    NASA Astrophysics Data System (ADS)

    Du, Wen-Feng; Peng, Su-Ping

    2014-06-01

    In order to observe overburden media changes caused by mining processing, we take the fully-mechanized working face of the BLT coal mine in Shendong mine district as an example to develop a 4D seismic data acquisition methodology during coal mining. The 4D seismic data acquisition is implemented to collect 3D seismic data four times in different periods, such as before mining, during the mining process and after mining to observe the changes of the overburden layer during coal mining. The seismic data in the research area demonstrates that seismic waves are stronger in energy, higher in frequency and have better continuous reflectors before coal mining. However, all this is reversed after coal mining because the overburden layer has been mined, the seismic energy and frequency decrease, and reflections have more discontinuities. Comparing the records collected in the survey with those from newly mined areas and other records acquired in the same survey with the same geometry and with a long time for settling after mining, it clearly shows that the seismic reflections have stronger amplitudes and are more continuous because the media have recovered by overburden layer compaction after a long time of settling after mining. By 4D seismic acquisition, the original background investigation of the coal layers can be derived from the first records, then the layer structure changes can be monitored through the records of mining action and compaction action after mining. This method has laid the foundation for further research into the variation principles of the overburden layer under modern coal-mining conditions.

  2. Digit ratio (2D:4D), salivary testosterone, and handedness.

    PubMed

    Beaton, Alan A; Rudling, Nick; Kissling, Christian; Taurines, Regine; Thome, Johannes

    2011-03-01

    The length of the index finger relative to that of the ring finger, the 2D:4D ratio, has been taken to be a marker of the amount of testosterone (T) that was present in the foetal environment (Manning, Scutt, Wilson, & Lewis-Jones, 1998). It has also been suggested (Geschwind & Galaburda, 1987) that elevated levels of foetal T are associated with left-handedness and that adult levels of circulating T might relate to foetal levels (Jamison, Meier, & Campbell, 1993). We used multiple regression analyses to investigate whether there is any relationship between either left or right hand 2D:4D ratio and handedness. We also examined whether adult levels of salivary T (or cortisol, used as a control hormone) predict digit ratio and/or handedness. Although the 2D:4D ratio of neither the left nor the right hand was related to handedness, the difference between the digit ratios of the right and left hands, D(R-L), was a significant predictor of handedness and of the performance difference between the hands on a peg-moving task, supporting previous findings (Manning & Peters, 2009; Manning et al., 1998; Manning, Trivers, Thornhill, & Singh, 2000; Stoyanov, Marinov, & Pashalieva, 2009). Adult circulating T levels did not predict the digit ratio of the left or right hand; nor was there a significant relationship between concentrations of salivary T (or cortisol) and either hand preference or asymmetry in manual skill. We suggest that the association between D(R-L) and hand preference arises because D(R-L) is a correlate of sensitivity to T in the developing foetus.

  3. New Integrable 4D Quantum Field Theories from Strongly Deformed Planar N=4 Supersymmetric Yang-Mills Theory.

    PubMed

    Gürdoğan, Ömer; Kazakov, Vladimir

    2016-11-11

    We introduce a family of new integrable quantum field theories in four dimensions by considering the γ-deformed N=4 supersymmetric Yang-Mills (SYM) theory in the double scaling limit of large imaginary twists and small coupling. This limit discards the gauge fields and retains only certain Yukawa and scalar interactions with three arbitrary effective couplings. In the 't Hooft limit, these 4D theories are integrable, and contain a wealth of conformal correlators such that the whole arsenal of AdS/CFT integrability remains applicable. As a special case of these models, we obtain a quantum field theory of two complex scalars with a chiral, quartic interaction. The Berenstein-Maldacena-Nastase vacuum anomalous dimension is dominated in each loop order by a single "wheel" graph, whose bulk represents an integrable "fishnet" graph. This explicitly demonstrates the all-loop integrability of gamma-deformed planar N=4 SYM theory, at least in our limit. Using this feature and integrability results we provide an explicit conjecture for the periods of double-wheel graphs with an arbitrary number of spokes in terms of multiple zeta values of limited depth.

  4. New Integrable 4D Quantum Field Theories from Strongly Deformed Planar N =4 Supersymmetric Yang-Mills Theory

    NASA Astrophysics Data System (ADS)

    Gürdoǧan, Ömer; Kazakov, Vladimir

    2016-11-01

    We introduce a family of new integrable quantum field theories in four dimensions by considering the γ -deformed N =4 supersymmetric Yang-Mills (SYM) theory in the double scaling limit of large imaginary twists and small coupling. This limit discards the gauge fields and retains only certain Yukawa and scalar interactions with three arbitrary effective couplings. In the `t Hooft limit, these 4D theories are integrable, and contain a wealth of conformal correlators such that the whole arsenal of AdS /CFT integrability remains applicable. As a special case of these models, we obtain a quantum field theory of two complex scalars with a chiral, quartic interaction. The Berenstein-Maldacena-Nastase vacuum anomalous dimension is dominated in each loop order by a single "wheel" graph, whose bulk represents an integrable "fishnet" graph. This explicitly demonstrates the all-loop integrability of gamma-deformed planar N =4 SYM theory, at least in our limit. Using this feature and integrability results we provide an explicit conjecture for the periods of double-wheel graphs with an arbitrary number of spokes in terms of multiple zeta values of limited depth.

  5. Coupled tensorial forms of the second-order effective Hamiltonian for open-subshell atoms in jj-coupling

    SciTech Connect

    Jursenas, Rytis; Merkelis, Gintaras

    2011-01-15

    General expressions for the second-order effective atomic Hamiltonian are derived for open-subshell atoms in jj-coupling. The expansion terms are presented as N-body (N=0,1,2,3) effective operators given in the second quantization representation in coupled tensorial form. Two alternative coupled tensorial forms for each expansion term have been developed. To reduce the number of expressions of the effective Hamiltonian, the reduced matrix elements of antisymmetric two-particle wavefunctions are involved in the consideration. The general expressions presented allow the determination of the spin-angular part of expansion terms when studying correlation effects dealing with a number of problems in atomic structure calculations.

  6. Effectiveness of Group Reciprocity Counseling with Married Couples

    ERIC Educational Resources Information Center

    Dixon, David N.; Sciara, Anthony D.

    1977-01-01

    This research examined use of reciporcity procedures with married couples in a group format. Couples (N=7), enrolled in a non-credit extension course, participated in an eight-week workshop. Commitment to and optimism about marriage and ratings on three of nine areas of couple interaction significantly increased over the eight-week period. (Author)

  7. 4D micro-CT using fast prospective gating.

    PubMed

    Guo, Xiaolian; Johnston, Samuel M; Qi, Yi; Johnson, G Allan; Badea, Cristian T

    2012-01-07

    Micro-CT is currently used in preclinical studies to provide anatomical information. But, there is also significant interest in using this technology to obtain functional information. We report here a new sampling strategy for 4D micro-CT for functional cardiac and pulmonary imaging. Rapid scanning of free-breathing mice is achieved with fast prospective gating (FPG) implemented on a field programmable gate array. The method entails on-the-fly computation of delays from the R peaks of the ECG signals or the peaks of the respiratory signals for the triggering pulses. Projection images are acquired for all cardiac or respiratory phases at each angle before rotating to the next angle. FPG can deliver the faster scan time of retrospective gating (RG) with the regular angular distribution of conventional prospective gating for cardiac or respiratory gating. Simultaneous cardio-respiratory gating is also possible with FPG in a hybrid retrospective/prospective approach. We have performed phantom experiments to validate the new sampling protocol and compared the results from FPG and RG in cardiac imaging of a mouse. Additionally, we have evaluated the utility of incorporating respiratory information in 4D cardiac micro-CT studies with FPG. A dual-source micro-CT system was used for image acquisition with pulsed x-ray exposures (80 kVp, 100 mA, 10 ms). The cardiac micro-CT protocol involves the use of a liposomal blood pool contrast agent containing 123 mg I ml(-1) delivered via a tail vein catheter in a dose of 0.01 ml g(-1) body weight. The phantom experiment demonstrates that FPG can distinguish the successive phases of phantom motion with minimal motion blur, and the animal study demonstrates that respiratory FPG can distinguish inspiration and expiration. 4D cardiac micro-CT imaging with FPG provides image quality superior to RG at an isotropic voxel size of 88 μm and 10 ms temporal resolution. The acquisition time for either sampling approach is less than 5 min. The

  8. 4D Flow MRI in Neuroradiology: Techniques and Applications.

    PubMed

    Pereira, Vitor Mendes; Delattre, Benedicte; Brina, Olivier; Bouillot, Pierre; Vargas, Maria Isabel

    2016-04-01

    Assessment of the intracranial flow is important for the understanding and management of cerebral vascular diseases. From brain aneurysms and arteriovenous malformations lesions to intracranial and cervical stenosis, the appraisal of the blood flow can be crucial and influence positively on patients' management. The determination of the intracranial hemodynamics and the collateral pattern seems to play to a major role in the management of these lesions. 4D flow magnetic resonance imaging is a noninvasive phase contrast derived method that has been developed and applied in neurovascular diseases. It has a great potential if followed by further technical improvements and comprehensive and systematic clinical studies.

  9. Realistic CT simulation using the 4D XCAT phantom

    PubMed Central

    Segars, W. P.; Mahesh, M.; Beck, T. J.; Frey, E. C.; Tsui, B. M. W.

    2008-01-01

    The authors develop a unique CT simulation tool based on the 4D extended cardiac-torso (XCAT) phantom, a whole-body computer model of the human anatomy and physiology based on NURBS surfaces. Unlike current phantoms in CT based on simple mathematical primitives, the 4D XCAT provides an accurate representation of the complex human anatomy and has the advantage, due to its design, that its organ shapes can be changed to realistically model anatomical variations and patient motion. A disadvantage to the NURBS basis of the XCAT, however, is that the mathematical complexity of the surfaces makes the calculation of line integrals through the phantom difficult. They have to be calculated using iterative procedures; therefore, the calculation of CT projections is much slower than for simpler mathematical phantoms. To overcome this limitation, the authors used efficient ray tracing techniques from computer graphics, to develop a fast analytic projection algorithm to accurately calculate CT projections directly from the surface definition of the XCAT phantom given parameters defining the CT scanner and geometry. Using this tool, realistic high-resolution 3D and 4D projection images can be simulated and reconstructed from the XCAT within a reasonable amount of time. In comparison with other simulators with geometrically defined organs, the XCAT-based algorithm was found to be only three times slower in generating a projection data set of the same anatomical structures using a single 3.2 GHz processor. To overcome this decrease in speed would, therefore, only require running the projection algorithm in parallel over three processors. With the ever decreasing cost of computers and the rise of faster processors and multi-processor systems and clusters, this slowdown is basically inconsequential, especially given the vast improvement the XCAT offers in terms of realism and the ability to generate 3D and 4D data from anatomically diverse patients. As such, the authors conclude

  10. Founding Gravitation in 4D Euclidean Space-Time Geometry

    SciTech Connect

    Winkler, Franz-Guenter

    2010-11-24

    The Euclidean interpretation of special relativity which has been suggested by the author is a formulation of special relativity in ordinary 4D Euclidean space-time geometry. The natural and geometrically intuitive generalization of this view involves variations of the speed of light (depending on location and direction) and a Euclidean principle of general covariance. In this article, a gravitation model by Jan Broekaert, which implements a view of relativity theory in the spirit of Lorentz and Poincare, is reconstructed and shown to fulfill the principles of the Euclidean approach after an appropriate reinterpretation.

  11. Problems with vector confinement in 4d QCD

    NASA Astrophysics Data System (ADS)

    Simonov, Yu. A.

    2017-07-01

    It is shown that vector confinement does not support bound state spectrum in the 4d Dirac equation. The same property is confirmed in the heavy-light and light-light QCD systems. This situation is compared with the confinement in the 2d system, which is generated by the gluon exchange. Considering the existing theories of confinement, it is shown that both the field correlator approach and the dual superconductor model ensure the scalar confinement in contrast to the Gribov-Zwanziger model, where the confning Coulomb potential does not support bound states in the Dirac equation..

  12. 4D micro-CT using fast prospective gating

    NASA Astrophysics Data System (ADS)

    Guo, Xiaolian; Johnston, Samuel M.; Qi, Yi; Johnson, G. Allan; Badea, Cristian T.

    2012-01-01

    Micro-CT is currently used in preclinical studies to provide anatomical information. But, there is also significant interest in using this technology to obtain functional information. We report here a new sampling strategy for 4D micro-CT for functional cardiac and pulmonary imaging. Rapid scanning of free-breathing mice is achieved with fast prospective gating (FPG) implemented on a field programmable gate array. The method entails on-the-fly computation of delays from the R peaks of the ECG signals or the peaks of the respiratory signals for the triggering pulses. Projection images are acquired for all cardiac or respiratory phases at each angle before rotating to the next angle. FPG can deliver the faster scan time of retrospective gating (RG) with the regular angular distribution of conventional prospective gating for cardiac or respiratory gating. Simultaneous cardio-respiratory gating is also possible with FPG in a hybrid retrospective/prospective approach. We have performed phantom experiments to validate the new sampling protocol and compared the results from FPG and RG in cardiac imaging of a mouse. Additionally, we have evaluated the utility of incorporating respiratory information in 4D cardiac micro-CT studies with FPG. A dual-source micro-CT system was used for image acquisition with pulsed x-ray exposures (80 kVp, 100 mA, 10 ms). The cardiac micro-CT protocol involves the use of a liposomal blood pool contrast agent containing 123 mg I ml-1 delivered via a tail vein catheter in a dose of 0.01 ml g-1 body weight. The phantom experiment demonstrates that FPG can distinguish the successive phases of phantom motion with minimal motion blur, and the animal study demonstrates that respiratory FPG can distinguish inspiration and expiration. 4D cardiac micro-CT imaging with FPG provides image quality superior to RG at an isotropic voxel size of 88 µm and 10 ms temporal resolution. The acquisition time for either sampling approach is less than 5 min. The

  13. Multielectron spectroscopy: the xenon 4d hole double auger decay.

    PubMed

    Penent, F; Palaudoux, J; Lablanquie, P; Andric, L; Feifel, R; Eland, J H D

    2005-08-19

    A magnetic bottle spectrometer of the type recently developed by Eland et al. [Phys. Rev. Lett. 90, 053003 (2003).] has been implemented for use with synchrotron radiation, allowing multidimensional electron spectroscopy. Its application to the Xe 4d double Auger decay reveals all the energy pathways involved. The dominant path is a cascade process with a rapid (6 fs) ejection of a first Auger electron followed by the slower (>23 fs) emission of a second Auger electron. Weaker processes implying 3 electron processes are also revealed, namely, direct double Auger and associated Rydberg series.

  14. CMT4D (NDRG1 mutation): genotype-phenotype correlations.

    PubMed

    Ricard, Emilie; Mathis, Stéphane; Magdelaine, Corinne; Delisle, Marie-Bernadette; Magy, Laurent; Funalot, Benoît; Vallat, Jean-Michel

    2013-09-01

    Charcot-Marie-Tooth (CMT) disease is a heterogeneous condition with a large number of clinical, electrophysiological and pathological phenotypes. More than 40 genes are involved. We report a child of gypsy origin with an autosomal recessive demyelinating phenotype. Clinical data, familial history, and electrophysiological studies were in favor of a CMT4 sub-type. The characteristic N-Myc downstream-regulated gene 1 (NDRG1) mutation responsible for this CMT4D phenotype was confirmed: p.R148X. The exact molecular function of the NDRG1 protein has yet to be elucidated.

  15. Realistic CT simulation using the 4D XCAT phantom.

    PubMed

    Segars, W P; Mahesh, M; Beck, T J; Frey, E C; Tsui, B M W

    2008-08-01

    The authors develop a unique CT simulation tool based on the 4D extended cardiac-torso (XCAT) phantom, a whole-body computer model of the human anatomy and physiology based on NURBS surfaces. Unlike current phantoms in CT based on simple mathematical primitives, the 4D XCAT provides an accurate representation of the complex human anatomy and has the advantage, due to its design, that its organ shapes can be changed to realistically model anatomical variations and patient motion. A disadvantage to the NURBS basis of the XCAT, however, is that the mathematical complexity of the surfaces makes the calculation of line integrals through the phantom difficult. They have to be calculated using iterative procedures; therefore, the calculation of CT projections is much slower than for simpler mathematical phantoms. To overcome this limitation, the authors used efficient ray tracing techniques from computer graphics, to develop a fast analytic projection algorithm to accurately calculate CT projections directly from the surface definition of the XCAT phantom given parameters defining the CT scanner and geometry. Using this tool, realistic high-resolution 3D and 4D projection images can be simulated and reconstructed from the XCAT within a reasonable amount of time. In comparison with other simulators with geometrically defined organs, the XCAT-based algorithm was found to be only three times slower in generating a projection data set of the same anatomical structures using a single 3.2 GHz processor. To overcome this decrease in speed would, therefore, only require running the projection algorithm in parallel over three processors. With the ever decreasing cost of computers and the rise of faster processors and multi-processor systems and clusters, this slowdown is basically inconsequential, especially given the vast improvement the XCAT offers in terms of realism and the ability to generate 3D and 4D data from anatomically diverse patients. As such, the authors conclude

  16. Oblique sounding using the DPS-4D stations in Europe

    NASA Astrophysics Data System (ADS)

    Mosna, Zbysek; Kouba, Daniel; Koucka Knizova, Petra; Arikan, Feza; Arikan, Orhan; Gok, Gokhan; Rejfek, Lubos

    2016-07-01

    The DPS-4D Digisondes are capable of detection of echoes from neighbouring European stations. Currently, a campaign with high-temporal resolution of 5 min is being run. Further, ionograms from regular vertical sounding with 15 min resolution provide us with oblique reflections together with vertical reflections. We analyzed profiles of electron concentration and basic ionospheric parameters derived from the ionograms. We compared results derived from reflections from the ionosphere above the stations (vertical sounding) with information derived from oblique reflections between the stations. This study is supported by the Joint TUBITAK 114E092 and AS CR 14/001 projects.

  17. Volumetric limiting spatial resolution analysis of four dimensional digital subtraction angiography (4D-DSA)

    NASA Astrophysics Data System (ADS)

    Davis, Brian; Oberstar, Erick; Royalty, Kevin; Schafer, Sebastian; Strother, Charles; Mistretta, Charles

    2015-03-01

    Static C-Arm CT 3D FDK baseline reconstructions (3D-DSA) are unable to provide temporal information to radiologists. 4D-DSA provides a time series of 3D volumes implementing a constrained image, thresholded 3D-DSA, reconstruction utilizing temporal dynamics in the 2D projections. Volumetric limiting spatial resolution (VLSR) of 4DDSA is quantified and compared to a 3D-DSA reconstruction using the same 3D-DSA parameters. Investigated were the effects of varying over significant ranges the 4D-DSA parameters of 2D blurring kernel size applied to the projection and threshold applied to the 3D-DSA when generating the constraining image of a scanned phantom (SPH) and an electronic phantom (EPH). The SPH consisted of a 76 micron tungsten wire encased in a 47 mm O.D. plastic radially concentric thin walled support structure. An 8-second/248-frame/198° scan protocol acquired the raw projection data. VLSR was determined from averaged MTF curves generated from each 2D transverse slice of every (248) 4D temporal frame (3D). 4D results for SPH and EPH were compared to the 3D-DSA. Analysis of the 3D-DSA resulted in a VLSR of 2.28 and 1.69 lp/mm for the EPH and SPH respectively. Kernel (2D) sizes of either 10x10 or 20x20 pixels with a threshold of 10% of the 3D-DSA as a constraining image provided 4D-DSA VLSR nearest to the 3D-DSA. 4D-DSA algorithms yielded 2.21 and 1.67 lp/mm with a percent error of 3.1% and 1.2% for the EPH and SPH respectively as compared to the 3D-DSA. This research indicates 4D-DSA is capable of retaining the resolution of the 3D-DSA.

  18. The effect of coupling on bubble fragmentation acoustics.

    PubMed

    Czerski, Helen; Deane, Grant B

    2011-01-01

    Understanding the formation and evolution of bubble populations is important in a wide range of situations, including industrial processes, medical applications, and ocean science. Passive acoustical techniques can be used to track changes in the population, since each bubble formation or fragmentation event is likely to produce sound. This sound potentially contains a wealth of information about the fragmentation process and the products, but to fully exploit these data it is necessary to understand the physical processes that determine its characteristics. The focus of this paper is binary fragmentation, when turbulence causes one bubble to split into two. Specifically, the effect that bubble-bubble coupling has on the sound produced is examined. A numerical simulation of the acoustical excitation of fragmenting bubbles is used to generate model acoustic signals, which are compared with experimental data. A frequency range with a suppressed acoustic output which is observed in the experimental data can be explained when coupling is taken into account. In addition, although the driving mechanism of neck collapse is always consistent with the data for the larger bubble of the newly formed pair, a different mechanism must be driving the smaller bubble in some situations.

  19. Effective field theory of weakly coupled inflationary models

    SciTech Connect

    Gwyn, Rhiannon; Palma, Gonzalo A.; Sakellariadou, Mairi; Sypsas, Spyros E-mail: gpalmaquilod@ing.uchile.cl E-mail: spyridon.sypsas@kcl.ac.uk

    2013-04-01

    The application of Effective Field Theory (EFT) methods to inflation has taken a central role in our current understanding of the very early universe. The EFT perspective has been particularly useful in analyzing the self-interactions determining the evolution of co-moving curvature perturbations (Goldstone boson modes) and their influence on low-energy observables. However, the standard EFT formalism, to lowest order in spacetime differential operators, does not provide the most general parametrization of a theory that remains weakly coupled throughout the entire low-energy regime. Here we study the EFT formulation by including spacetime differential operators implying a scale dependence of the Goldstone boson self-interactions and its dispersion relation. These operators are shown to arise naturally from the low-energy interaction of the Goldstone boson with heavy fields that have been integrated out. We find that the EFT then stays weakly coupled all the way up to the cutoff scale at which ultraviolet degrees of freedom become operative. This opens up a regime of new physics where the dispersion relation is dominated by a quadratic dependence on the momentum ω ∼ p{sup 2}. In addition, provided that modes crossed the Hubble scale within this energy range, the predictions of inflationary observables — including non-Gaussian signatures — are significantly affected by the new scales characterizing it.

  20. Radiolucent 4D Ultrasound Imaging: System Design and Application to Radiotherapy Guidance.

    PubMed

    Schlosser, Jeffrey; Hristov, Dimitre

    2016-04-27

    Four-dimensional (4D) ultrasound (US) is an attractive modality for image guidance due to its real-time, non-ionizing, volumetric imaging capability with high soft tissue contrast. However, existing 4D US imaging systems contain large volumes of metal which interfere with diagnostic and therapeutic ionizing radiation in procedures such as CT imaging and radiation therapy. This study aimed to design and characterize a novel 4D Radiolucent Remotely-Actuated UltraSound Scanning (RRUSS) device that overcomes this limitation. In a phantom, we evaluated the imaging performance of the RRUSS device including frame rate, resolution, spatial integrity, and motion tracking accuracy. To evaluate compatibility with radiation therapy workflow, we evaluated device-induced CT imaging artifacts, US tracking performance during beam delivery, and device compatibility with commercial radiotherapy planning software. The RRUSS device produced 4D volumes at 0.1-3.0 Hz with 60⁰ lateral field of view (FOV), 50⁰ maximum elevational FOV, and 200 mm maximum depth. Imaging resolution (-3 dB point spread width) was 1.2-7.9 mm at depths up to 100 mm and motion tracking accuracy was ≤0.3±0.5 mm. No significant effect of the RRUSS device on CT image integrity was found, and RRUSS device performance was not affected by radiotherapy beam exposure. Agreement within ±3.0% / 2.0 mm was achieved between computed and measured radiotherapy dose delivered directly through the RRUSS device at 6 MV and 15 MV. In-vivo liver, kidney, and prostate images were successfully acquired. Our investigations suggest that a RRUSS device can offer non-interfering 4D guidance for radiation therapy and other diagnostic and therapeutic procedures.

  1. Radiolucent 4D Ultrasound Imaging: System Design and Application to Radiotherapy Guidance.

    PubMed

    Schlosser, Jeffrey; Hristov, Dimitre

    2016-10-01

    Four-dimensional (4D) ultrasound (US) is an attractive modality for image guidance due to its real-time, non-ionizing, volumetric imaging capability with high soft tissue contrast. However, existing 4D US imaging systems contain large volumes of metal which interfere with diagnostic and therapeutic ionizing radiation in procedures such as CT imaging and radiation therapy. This study aimed to design and characterize a novel 4D Radiolucent Remotely-Actuated UltraSound Scanning (RRUSS) device that overcomes this limitation. In a phantom, we evaluated the imaging performance of the RRUSS device including frame rate, resolution, spatial integrity, and motion tracking accuracy. To evaluate compatibility with radiation therapy workflow, we evaluated device-induced CT imaging artifacts, US tracking performance during beam delivery, and device compatibility with commercial radiotherapy planning software. The RRUSS device produced 4D volumes at 0.1-3.0 Hz with 60° lateral field of view (FOV), 50° maximum elevational FOV, and 200 mm maximum depth. Imaging resolution (-3 dB point spread width) was 1.2-7.9 mm at depths up to 100 mm and motion tracking accuracy was ≤ 0.3±0.5 mm. No significant effect of the RRUSS device on CT image integrity was found, and RRUSS device performance was not affected by radiotherapy beam exposure. Agreement within ±3.0% / 2.0 mm was achieved between computed and measured radiotherapy dose delivered directly through the RRUSS device at 6 MV and 15 MV. In vivo liver, kidney, and prostate images were successfully acquired. Our investigations suggest that a RRUSS device can offer non-interfering 4D guidance for radiation therapy and other diagnostic and therapeutic procedures.

  2. Matrix effects in inductively coupled plasma mass spectrometry

    SciTech Connect

    Chen, Xiaoshan

    1995-07-07

    The inductively coupled plasma is an electrodeless discharge in a gas (usually Ar) at atmospheric pressure. Radio frequency energy generated by a RF power source is inductively coupled to the plasma gas through a water cooled load coil. In ICP-MS the "Fassel" TAX quartz torch commonly used in emission is mounted horizontally. The sample aerosol is introduced into the central flow, where the gas kinetic temperature is about 5000 K. The aerosol is vaporized, atomized, excited and ionized in the plasma, and the ions are subsequently extracted through two metal apertures (sampler and skimmer) into the mass spectrometer. In ICP-MS, the matrix effects, or non-spectroscopic interferences, can be defined as the type of interferences caused by dissolved concomitant salt ions in the solution. Matrix effects can be divided into two categories: (1) signal drift due to the deposition of solids on the sampling apertures; and/or (2) signal suppression or enhancement by the presence of the dissolved salts. The first category is now reasonably understood. The dissolved salts, especially refractory oxides, tend to deposit on the cool tip of the sampling cone. The clogging of the orifices reduces the ion flow into the ICP-MS, lowers the pressure in the first stage of ICP-MS, and enhances the level of metal oxide ions. Because the extent of the clogging increases with the time, the signal drifts down. Even at the very early stage of the development of ICP-MS, matrix effects had been observed. Houk et al. found out that the ICP-MS was not tolerant to solutions containing significant amounts of dissolved solids.

  3. The effects of shape anisotropy and exchange coupling on spin precession frequencies in exchange coupled Co/Cu/Py trilayers

    NASA Astrophysics Data System (ADS)

    Keramati, Sam; Singh, Uday; Kurfman, Seth; Binek, Ch.; Adenwalla, S.

    2015-03-01

    Ultrafast high-power laser systems have successfully opened up the field of magnetization dynamics, studying subpicosecond laser-induced spin precession dynamics, demagnetization processes and magnetization reorientation. Here we investigate laser-induced magnetization dynamics in a series of photolithographically patterned microstructures of exchange coupled trilayers of Co/Cu/Py grown on Si substrates. The microstructures have different shape anisotropies as well as different exchange coupling parameters. The latter determines the magnetization state, varying from ferromagnetically to anti-ferromagnetically coupled. We explore how the different spin precession frequencies of the constituent exchange coupled magnetic layers with unequal relaxation times can trade-off with the differing shape anisotropies. The key physical point is that the precession frequency of ferromagnetic materials and their damping parameter vary with the effective field which depends on both the shape anisotropy, and exchange coupling, while their corresponding effects can be modulated through the action of the intense pump beam. Precession frequency maps of the behavior of the exchange coupling parameter of the samples with respect to their shape anisotropy and their laser-induced modulated precession frequencies will be generated through a pump-probe experiment to address the above-mentioned objective of our work. This work is supported by NSF Grant No. 1409622 and MRSEC DMR-0820521.

  4. Detecting effective connectivity in networks of coupled neuronal oscillators.

    PubMed

    Boykin, Erin R; Khargonekar, Pramod P; Carney, Paul R; Ogle, William O; Talathi, Sachin S

    2012-06-01

    The application of data-driven time series analysis techniques such as Granger causality, partial directed coherence and phase dynamics modeling to estimate effective connectivity in brain networks has recently gained significant prominence in the neuroscience community. While these techniques have been useful in determining causal interactions among different regions of brain networks, a thorough analysis of the comparative accuracy and robustness of these methods in identifying patterns of effective connectivity among brain networks is still lacking. In this paper, we systematically address this issue within the context of simple networks of coupled spiking neurons. Specifically, we develop a method to assess the ability of various effective connectivity measures to accurately determine the true effective connectivity of a given neuronal network. Our method is based on decision tree classifiers which are trained using several time series features that can be observed solely from experimentally recorded data. We show that the classifiers constructed in this work provide a general framework for determining whether a particular effective connectivity measure is likely to produce incorrect results when applied to a dataset.

  5. Effects of Behavioral Marital Therapy on Couples' Communication and Problem-Solving Skills.

    ERIC Educational Resources Information Center

    Hahlweg, Kurt; And Others

    1984-01-01

    Examined the effectiveness of behavioral marital therapy in improving communication and problem solving skills in 29 couples. Couples' problem discussions were videotaped and rated. Results showed that BMT was effective. The interaction patterns of the treated couples resembled patterns exhibited by nondistressed controls. (JAC)

  6. The Effects of Three Methods of Observation on Couples in Interactional Research.

    ERIC Educational Resources Information Center

    Carpenter, Linda J.; Merkel, William T.

    1988-01-01

    Assessed the effects of three different methods of observation of couples (one-way mirror, audio recording, and video recording) on 30 volunteer, nonclinical married couples. Results suggest that types of observation do not produce significantly different effects on nonclinical couples. (Author/ABL)

  7. Atlas construction for dynamic (4D) PET using diffeomorphic transformations.

    PubMed

    Bieth, Marie; Lombaert, Hervé; Reader, Andrew J; Siddiqi, Kaleem

    2013-01-01

    A novel dynamic (4D) PET to PET image registration procedure is proposed and applied to multiple PET scans acquired with the high resolution research tomograph (HRRT), the highest resolution human brain PET scanner available in the world. By extending the recent diffeomorphic log-demons (DLD) method and applying it to multiple dynamic [11C]raclopride scans from the HRRT, an important step towards construction of a PET atlas of unprecedented quality for [11C]raclopride imaging of the human brain has been achieved. Accounting for the temporal dimension in PET data improves registration accuracy when compared to registration of 3D to 3D time-averaged PET images. The DLD approach was chosen for its ease in providing both an intensity and shape template, through iterative sequential pair-wise registrations with fast convergence. The proposed method is applicable to any PET radiotracer, providing 4D atlases with useful applications in high accuracy PET data simulations and automated PET image analysis.

  8. 488-4D ASH LANDFILL CLOSURE CAP HELP MODELING

    SciTech Connect

    Phifer, M.

    2014-11-17

    At the request of Area Completion Projects (ACP) in support of the 488-4D Landfill closure, the Savannah River National Laboratory (SRNL) has performed Hydrologic Evaluation of Landfill Performance (HELP) modeling of the planned 488-4D Ash Landfill closure cap to ensure that the South Carolina Department of Health and Environmental Control (SCDHEC) limit of no more than 12 inches of head on top of the barrier layer (saturated hydraulic conductivity of no more than 1.0E-05 cm/s) in association with a 25-year, 24-hour storm event is not projected to be exceeded. Based upon Weber 1998 a 25-year, 24-hour storm event at the Savannah River Site (SRS) is 6.1 inches. The results of the HELP modeling indicate that the greatest peak daily head on top of the barrier layer (i.e. geosynthetic clay liner (GCL) or high density polyethylene (HDPE) geomembrane) for any of the runs made was 0.079 inches associated with a peak daily precipitation of 6.16 inches. This is well below the SCDHEC limit of 12 inches.

  9. Cancer Incidence of 2,4-D Production Workers

    PubMed Central

    Burns, Carol; Bodner, Kenneth; Swaen, Gerard; Collins, James; Beard, Kathy; Lee, Marcia

    2011-01-01

    Despite showing no evidence of carcinogenicity in laboratory animals, the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) has been associated with non-Hodgkin lymphoma (NHL) in some human epidemiology studies, albeit inconsistently. We matched an existing cohort of 2,4-D manufacturing employees with cancer registries in three US states resulting in 244 cancers compared to 276 expected cases. The Standardized Incidence Ratio (SIR) for the 14 NHL cases was 1.36 (95% Confidence Interval (CI) 0.74–2.29). Risk estimates were higher in the upper cumulative exposure and duration subgroups, yet not statistically significant. There were no clear patterns of NHL risk with period of hire and histology subtypes. Statistically significant results were observed for prostate cancer (SIR = 0.74, 95% CI 0.57–0.94), and “other respiratory” cancers (SIR = 3.79, 95% CI 1.22–8.84; 4 of 5 cases were mesotheliomas). Overall, we observed fewer cancer cases than expected, and a non statistically significant increase in the number of NHL cases. PMID:22016704

  10. Positive energy conditions in 4D conformal field theory

    DOE PAGES

    Farnsworth, Kara; Luty, Markus A.; Prilepina, Valentina

    2016-10-03

    Here, we argue that all consistent 4D quantum field theories obey a spacetime-averaged weak energy inequality < T00 > ≥ –C/L4, where L is the size of the smearing region, and C is a positive constant that depends on the theory. If this condition is violated, the theory has states that are indistinguishable from states of negative total energy by any local measurement, and we expect instabilities or other inconsistencies. We apply this condition to 4D conformal field theories, and find that it places constraints on the OPE coefficients of the theory. The constraints we find are weaker than themore » “conformal collider” constraints of Hofman and Maldacena. In 3D CFTs, the only constraint we find is equivalent to the positivity of 2-point function of the energy-momentum tensor, which follows from unitarity. Our calculations are performed using momentum-space Wightman functions, which are remarkably simple functions of momenta, and may be of interest in their own right.« less

  11. Positive energy conditions in 4D conformal field theory

    SciTech Connect

    Farnsworth, Kara; Luty, Markus A.; Prilepina, Valentina

    2016-10-03

    Here, we argue that all consistent 4D quantum field theories obey a spacetime-averaged weak energy inequality < T00 > ≥ –C/L4, where L is the size of the smearing region, and C is a positive constant that depends on the theory. If this condition is violated, the theory has states that are indistinguishable from states of negative total energy by any local measurement, and we expect instabilities or other inconsistencies. We apply this condition to 4D conformal field theories, and find that it places constraints on the OPE coefficients of the theory. The constraints we find are weaker than the “conformal collider” constraints of Hofman and Maldacena. In 3D CFTs, the only constraint we find is equivalent to the positivity of 2-point function of the energy-momentum tensor, which follows from unitarity. Our calculations are performed using momentum-space Wightman functions, which are remarkably simple functions of momenta, and may be of interest in their own right.

  12. Exploration of 4D MRI blood flow using stylistic visualization.

    PubMed

    van Pelt, Roy; Oliván Bescós, Javier; Breeuwer, Marcel; Clough, Rachel E; Gröller, M Eduard; ter Haar Romenij, Bart; Vilanova, Anna

    2010-01-01

    Insight into the dynamics of blood-flow considerably improves the understanding of the complex cardiovascular system and its pathologies. Advances in MRI technology enable acquisition of 4D blood-flow data, providing quantitative blood-flow velocities over time. The currently typical slice-by-slice analysis requires a full mental reconstruction of the unsteady blood-flow field, which is a tedious and highly challenging task, even for skilled physicians. We endeavor to alleviate this task by means of comprehensive visualization and interaction techniques. In this paper we present a framework for pre-clinical cardiovascular research, providing tools to both interactively explore the 4D blood-flow data and depict the essential blood-flow characteristics. The framework encompasses a variety of visualization styles, comprising illustrative techniques as well as improved methods from the established field of flow visualization. Each of the incorporated styles, including exploded planar reformats, flow-direction highlights, and arrow-trails, locally captures the blood-flow dynamics and may be initiated by an interactively probed vessel cross-section. Additionally, we present the results of an evaluation with domain experts, measuring the value of each of the visualization styles and related rendering parameters.

  13. Positive Energy Conditions in 4D Conformal Field Theory

    NASA Astrophysics Data System (ADS)

    Farnsworth, Kara; Luty, Markus; Prilepina, Valentina

    2016-03-01

    We argue that all consistent 4D quantum field theories obey a spacetime-averaged weak energy inequality avgT00 >= - C /L4 , where L is the size of the smearing region, and C is a positive constant that depends on the theory. If this condition is violated, the theory has states that are indistinguishable from states of negative total energy by any local measurement, and we expect instabilities or other inconsistencies. We apply this condition to 4D conformal field theories, and find that it places constraints on the OPE coefficients of the theory. The constraints we find are weaker than the ``conformal collider'' constraints of Hofman and Maldacena. We speculate that there may be theories that violate the Hofman-Maldacena bounds, but satisfy our bounds. In 3D CFTs, the only constraint we find is equivalent to the positivity of 2-point function of the energy-momentum tensor, which follows from unitarity. Our calculations are performed using momentum-space Wightman functions, which are remarkably simple functions of momenta, and may be of interest in their own right.

  14. Positive energy conditions in 4D conformal field theory

    NASA Astrophysics Data System (ADS)

    Farnsworth, Kara; Luty, Markus A.; Prilepina, Valentina

    2016-10-01

    We argue that all consistent 4D quantum field theories obey a spacetime-averaged weak energy inequality < T 00> ≥ - C/L 4, where L is the size of the smearing region, and C is a positive constant that depends on the theory. If this condition is violated, the theory has states that are indistinguishable from states of negative total energy by any local measurement, and we expect instabilities or other inconsistencies. We apply this condition to 4D conformal field theories, and find that it places constraints on the OPE coefficients of the theory. The constraints we find are weaker than the "conformal collider" constraints of Hofman and Maldacena. In 3D CFTs, the only constraint we find is equivalent to the positivity of 2-point function of the energy-momentum tensor, which follows from unitarity. Our calculations are performed using momentum-space Wightman functions, which are remarkably simple functions of momenta, and may be of interest in their own right.

  15. Perspective: 4D ultrafast electron microscopy—Evolutions and revolutions

    NASA Astrophysics Data System (ADS)

    Shorokhov, Dmitry; Zewail, Ahmed H.

    2016-02-01

    In this Perspective, the evolutionary and revolutionary developments of ultrafast electron imaging are overviewed with focus on the "single-electron concept" for probing methodology. From the first electron microscope of Knoll and Ruska [Z. Phys. 78, 318 (1932)], constructed in the 1930s, to aberration-corrected instruments and on, to four-dimensional ultrafast electron microscopy (4D UEM), the developments over eight decades have transformed humans' scope of visualization. The changes in the length and time scales involved are unimaginable, beginning with the micrometer and second domains, and now reaching the space and time dimensions of atoms in matter. With these advances, it has become possible to follow the elementary structural dynamics as it unfolds in real time and to provide the means for visualizing materials behavior and biological functions. The aim is to understand emergent phenomena in complex systems, and 4D UEM is now central for the visualization of elementary processes involved, as illustrated here with examples from past achievements and future outlook.

  16. 4D Dynamic Required Navigation Performance Final Report

    NASA Technical Reports Server (NTRS)

    Finkelsztein, Daniel M.; Sturdy, James L.; Alaverdi, Omeed; Hochwarth, Joachim K.

    2011-01-01

    New advanced four dimensional trajectory (4DT) procedures under consideration for the Next Generation Air Transportation System (NextGen) require an aircraft to precisely navigate relative to a moving reference such as another aircraft. Examples are Self-Separation for enroute operations and Interval Management for in-trail and merging operations. The current construct of Required Navigation Performance (RNP), defined for fixed-reference-frame navigation, is not sufficiently specified to be applicable to defining performance levels of such air-to-air procedures. An extension of RNP to air-to-air navigation would enable these advanced procedures to be implemented with a specified level of performance. The objective of this research effort was to propose new 4D Dynamic RNP constructs that account for the dynamic spatial and temporal nature of Interval Management and Self-Separation, develop mathematical models of the Dynamic RNP constructs, "Required Self-Separation Performance" and "Required Interval Management Performance," and to analyze the performance characteristics of these air-to-air procedures using the newly developed models. This final report summarizes the activities led by Raytheon, in collaboration with GE Aviation and SAIC, and presents the results from this research effort to expand the RNP concept to a dynamic 4D frame of reference.

  17. Steady-state benchmarks of DK4D: A time-dependent, axisymmetric drift-kinetic equation solver

    SciTech Connect

    Lyons, B. C.; Jardin, S. C.; Ramos, J. J.

    2015-05-15

    The DK4D code has been written to solve a set of time-dependent, axisymmetric, finite-Larmor-radius drift-kinetic equations (DKEs) for the non-Maxwellian part of the electron and ion distribution functions using the full, linearized Fokker–Planck–Landau collision operator. The plasma is assumed to be in the low- to finite-collisionality regime, as is found in the cores of modern and future magnetic confinement fusion experiments. Each DKE is formulated such that the perturbed distribution function carries no net density, parallel momentum, or kinetic energy. Rather, these quantities are contained within the background Maxwellians and would be evolved by an appropriate set of extended magnetohydrodynamic (MHD) equations. This formulation allows for straight-forward coupling of DK4D to existing extended MHD time evolution codes. DK4D uses a mix of implicit and explicit temporal representations and finite element and spectral spatial representations. These, along with other computational methods used, are discussed extensively. Steady-state benchmarks are then presented comparing the results of DK4D to expected analytic results at low collisionality, qualitatively, and to the Sauter analytic fits for the neoclassical conductivity and bootstrap current, quantitatively. These benchmarks confirm that DK4D is capable of solving for the correct, gyroaveraged distribution function in stationary magnetic equilibria. Furthermore, the results presented demonstrate how the exact drift-kinetic solution varies with collisionality as a function of the magnetic moment and the poloidal angle.

  18. Steady-state benchmarks of DK4D: A time-dependent, axisymmetric drift-kinetic equation solvera)

    NASA Astrophysics Data System (ADS)

    Lyons, B. C.; Jardin, S. C.; Ramos, J. J.

    2015-05-01

    The DK4D code has been written to solve a set of time-dependent, axisymmetric, finite-Larmor-radius drift-kinetic equations (DKEs) for the non-Maxwellian part of the electron and ion distribution functions using the full, linearized Fokker-Planck-Landau collision operator. The plasma is assumed to be in the low- to finite-collisionality regime, as is found in the cores of modern and future magnetic confinement fusion experiments. Each DKE is formulated such that the perturbed distribution function carries no net density, parallel momentum, or kinetic energy. Rather, these quantities are contained within the background Maxwellians and would be evolved by an appropriate set of extended magnetohydrodynamic (MHD) equations. This formulation allows for straight-forward coupling of DK4D to existing extended MHD time evolution codes. DK4D uses a mix of implicit and explicit temporal representations and finite element and spectral spatial representations. These, along with other computational methods used, are discussed extensively. Steady-state benchmarks are then presented comparing the results of DK4D to expected analytic results at low collisionality, qualitatively, and to the Sauter analytic fits for the neoclassical conductivity and bootstrap current, quantitatively. These benchmarks confirm that DK4D is capable of solving for the correct, gyroaveraged distribution function in stationary magnetic equilibria. Furthermore, the results presented demonstrate how the exact drift-kinetic solution varies with collisionality as a function of the magnetic moment and the poloidal angle.

  19. Effective potential kinetic theory for strongly coupled plasmas

    NASA Astrophysics Data System (ADS)

    Baalrud, Scott D.; Daligault, Jérôme

    2016-11-01

    The effective potential theory (EPT) is a recently proposed method for extending traditional plasma kinetic and transport theory into the strongly coupled regime. Validation from experiments and molecular dynamics simulations have shown it to be accurate up to the onset of liquid-like correlation parameters (corresponding to Γ ≃ 10-50 for the one-component plasma, depending on the process of interest). Here, this theory is briefly reviewed along with comparisons between the theory and molecular dynamics simulations for self-diffusivity and viscosity of the one-component plasma. A number of new results are also provided, including calculations of friction coefficients, energy exchange rates, stopping power, and mobility. The theory is also cast in the Landau and Fokker-Planck kinetic forms, which may prove useful for enabling efficient kinetic computations.

  20. Effect of spatial distribution on the synchronization in rings of coupled oscillators

    NASA Astrophysics Data System (ADS)

    Ma, Hongjing; Liu, Weiqing; Wu, Ye; Yang, Yixian; Xiao, Jinghua

    2013-10-01

    In this paper, the effects of spatial distribution of coupling on the synchronizability are explored in a ring of diffusively coupled oscillators. We find that the inhomogeneity and spatial arrangements of coupling strength have great impacts on the synchronizability. When the inhomogeneous coupling constants are spatially rearranged, the eigenvalues λ2 (the second largest eigenvalue of the coupling matrixes) for all possible spatial arrangements, which may describe the synchronizability of coupled oscillators, obey a log-normal distribution. The spatial arrangement of period 1 achieves the best synchronizability while that of period 2 has the worst one. In addition, the regimes of the effects of spatial distribution on synchronizability are analyzed by a ring of coupled Rossler systems. The spatial rearrangement of coupling has meaningful applications in the manipulation of self- organization for coupled systems.

  1. Experimental identification of smart material coupling effects in composite structures

    NASA Astrophysics Data System (ADS)

    Chesne, S.; Jean-Mistral, C.; Gaudiller, L.

    2013-07-01

    Smart composite structures have an enormous potential for industrial applications, in terms of mass reduction, high material resistance and flexibility. The correct characterization of these complex structures is essential for active vibration control or structural health monitoring applications. The identification process generally calls for the determination of a generalized electromechanical coupling coefficient. As this process can in practice be difficult to implement, an original approach, presented in this paper, has been developed for the identification of the coupling effects of a smart material used in a composite curved beam. The accuracy of the proposed identification technique is tested by applying active modal control to the beam, using a reduced model based on this identification. The studied structure was as close to reality as possible, and made use of integrated transducers, low-cost sensors, clamped boundary conditions and substantial, complex excitation sources. PVDF (polyvinylidene fluoride) and MFC (macrofiber composite) transducers were integrated into the composite structure, to ensure their protection from environmental damage. The experimental identification described here was based on a curve fitting approach combined with the reduced model. It allowed a reliable, powerful modal control system to be built, controlling two modes of the structure. A linear quadratic Gaussian algorithm was used to determine the modal controller-observer gains. The selected modes were found to have an attenuation as strong as -13 dB in experiments, revealing the effectiveness of this method. In this study a generalized approach is proposed, which can be extended to most complex or composite industrial structures when they are subjected to vibration.

  2. P -wave coupled channel effects in electron-positron annihilation

    NASA Astrophysics Data System (ADS)

    Du, Meng-Lin; Meißner, Ulf-G.; Wang, Qian

    2016-11-01

    P -wave coupled channel effects arising from the D D ¯, D D¯ *+c .c . , and D*D¯* thresholds in e+e- annihilations are systematically studied. We provide an exploratory study by solving the Lippmann-Schwinger equation with short-ranged contact potentials obtained in the heavy quark limit. These contact potentials can be extracted from the P -wave interactions in the e+e- annihilations, and then be employed to investigate possible isosinglet P -wave hadronic molecules. In particular, such an investigation may provide information about exotic candidates with quantum numbers JPC=1-+ . In the mass region of the D D ¯, D D¯ *+c .c . , and D*D¯* thresholds, there are two quark model bare states, i.e. the ψ (3770 ) and ψ (4040 ), which are assigned as (13D1) and (31S1) states, respectively. By an overall fit of the cross sections of e+e-→D D ¯, D D¯ *+c .c . , D*D¯*, we determine the physical coupling constants to each channel and extract the pole positions of the ψ (3770 ) and ψ (4040 ). The deviation of the ratios from that in the heavy quark spin symmetry (HQSS) limit reflects the HQSS breaking effect due to the mass splitting between the D and the D*. Besides the two poles, we also find a pole a few MeV above the D D¯ *+c .c . threshold which can be related to the so-called G (3900 ) observed earlier by BABAR and Belle. This scenario can be further scrutinized by measuring the angular distribution in the D*D¯* channel with high luminosity experiments.

  3. 2D/4D marker-free tumor tracking using 4D CBCT as the reference image.

    PubMed

    Wang, Mengjiao; Sharp, Gregory C; Rit, Simon; Delmon, Vivien; Wang, Guangzhi

    2014-05-07

    Tumor motion caused by respiration is an important issue in image-guided radiotherapy. A 2D/4D matching method between 4D volumes derived from cone beam computed tomography (CBCT) and 2D fluoroscopic images was implemented to track the tumor motion without the use of implanted markers. In this method, firstly, 3DCBCT and phase-rebinned 4DCBCT are reconstructed from cone beam acquisition. Secondly, 4DCBCT volumes and a streak-free 3DCBCT volume are combined to improve the image quality of the digitally reconstructed radiographs (DRRs). Finally, the 2D/4D matching problem is converted into a 2D/2D matching between incoming projections and DRR images from each phase of the 4DCBCT. The diaphragm is used as a target surrogate for matching instead of using the tumor position directly. This relies on the assumption that if a patient has the same breathing phase and diaphragm position as the reference 4DCBCT, then the tumor position is the same. From the matching results, the phase information, diaphragm position and tumor position at the time of each incoming projection acquisition can be derived. The accuracy of this method was verified using 16 candidate datasets, representing lung and liver applications and one-minute and two-minute acquisitions. The criteria for the eligibility of datasets were described: 11 eligible datasets were selected to verify the accuracy of diaphragm tracking, and one eligible dataset was chosen to verify the accuracy of tumor tracking. The diaphragm matching accuracy was 1.88 ± 1.35 mm in the isocenter plane and the 2D tumor tracking accuracy was 2.13 ± 1.26 mm in the isocenter plane. These features make this method feasible for real-time marker-free tumor motion tracking purposes.

  4. 2D/4D marker-free tumor tracking using 4D CBCT as the reference image

    NASA Astrophysics Data System (ADS)

    Wang, Mengjiao; Sharp, Gregory C.; Rit, Simon; Delmon, Vivien; Wang, Guangzhi

    2014-05-01

    Tumor motion caused by respiration is an important issue in image-guided radiotherapy. A 2D/4D matching method between 4D volumes derived from cone beam computed tomography (CBCT) and 2D fluoroscopic images was implemented to track the tumor motion without the use of implanted markers. In this method, firstly, 3DCBCT and phase-rebinned 4DCBCT are reconstructed from cone beam acquisition. Secondly, 4DCBCT volumes and a streak-free 3DCBCT volume are combined to improve the image quality of the digitally reconstructed radiographs (DRRs). Finally, the 2D/4D matching problem is converted into a 2D/2D matching between incoming projections and DRR images from each phase of the 4DCBCT. The diaphragm is used as a target surrogate for matching instead of using the tumor position directly. This relies on the assumption that if a patient has the same breathing phase and diaphragm position as the reference 4DCBCT, then the tumor position is the same. From the matching results, the phase information, diaphragm position and tumor position at the time of each incoming projection acquisition can be derived. The accuracy of this method was verified using 16 candidate datasets, representing lung and liver applications and one-minute and two-minute acquisitions. The criteria for the eligibility of datasets were described: 11 eligible datasets were selected to verify the accuracy of diaphragm tracking, and one eligible dataset was chosen to verify the accuracy of tumor tracking. The diaphragm matching accuracy was 1.88 ± 1.35 mm in the isocenter plane and the 2D tumor tracking accuracy was 2.13 ± 1.26 mm in the isocenter plane. These features make this method feasible for real-time marker-free tumor motion tracking purposes.

  5. Digit ratio (2D:4D) and male facial attractiveness: new data and a meta-analysis.

    PubMed

    Hönekopp, Johannes

    2013-10-01

    Digit ratio (2D:4D) appears to correlate negatively with prenatal testosterone (T) effects in humans. As T probably increases facial masculinity, which in turn might be positively related to male facial attractiveness, a number of studies have looked into the relationship between 2D:4D and male facial attractiveness, showing equivocal results. Here, I present the largest and third largest samples so far, which investigate the relationship between 2D:4D and male facial attractiveness in adolescents (n = 115) and young men (n = 80). I then present random-effects meta-analyses of the available data (seven to eight samples, overall n = 362 to 469). These showed small (r ≈ -.09), statistically non-significant relationships between 2D:4D measures and male facial attractiveness. Thus, 2D:4D studies offer no convincing evidence at present that prenatal T has a positive effect on male facial attractiveness. However, a consideration of confidence intervals shows that, at present, a theoretically meaningful relationship between 2D:4D and male facial attractiveness cannot be ruled out either.

  6. Digit ratio 2D:4D in relation to autism spectrum disorders, empathizing, and systemizing: a quantitative review.

    PubMed

    Hönekopp, Johannes

    2012-08-01

    Prenatal testosterone (PT) effects have been proposed to increase systemizing (the drive to understand lawful input-output relationships), to decrease empathizing (the drive to understand others), and to cause autism via hypermasculinization of the brain. Digit ratio 2D:4D is a putative marker of PT effects in humans. An online study (n = 1896) into the relationship between the Reading the Mind in the Eyes Test (a widely used measure of empathizing) and self-measured 2D:4D in a nonclinical sample is reported. No evidence for a link between empathizing and 2D:4D in either females or males emerged. Further, three meta-analyses are presented that look into the relationships of 2D:4D with autism spectrum disorder (ASD), systemizing, and empathizing. 2D:4D was substantially lower (more masculine) in ASD-affected individuals than in normal controls (d = -0.58, P < 0.001). However, 2D:4D was found to be virtually unrelated to systemizing and empathizing in normal adults. The results support the idea that high PT is a risk factor for autism, but they challenge the view that PT substantially contributes to sex differences in systemizing and empathizing. Possibly, this pattern reflects an interaction effect, whereby PT drives ASD characteristic changes only in brains with a specific damage. © 2012 International Society for Autism Research, Wiley Periodicals, Inc.

  7. Neurobehavioral toxicity and tolerance to the herbicide 2,4-dichlorophenoxyacetic acid-n-butyl ester (2,4-D ester).

    PubMed

    Schulze, G E; Dougherty, J A

    1988-04-01

    2,4-Dichlorophenoxyacetic acid (2,4-D) is a commonly used herbicide and one component of Agent Orange. The subchronic neurobehavioral toxicity of 2,4-D-n-butyl ester (2,4-D ester) was assessed in rats by monitoring performance in a battery of behavioral tests. 2,4-D ester was injected daily (150-250 mg/kg sc) in four successive 14-day periods. Five- to eight-day exposure-free periods separated dosing escalations. All doses produced a significant decrease in schedule-controlled lever pressing and photocell locomotor activity while increasing landing foot splay. Peak effects occurred by the 3rd injection, while tolerance developed by the 10th injection. Neurobehavioral effects associated with 2,4-D ester exposure were rapidly reversible and disappeared within 24-48 hr. Brain and blood 2,4-D kinetics revealed that the compound accumulated in brain with repeated dosing. This observation indicates a cellular mechanism for tolerance development. Other neurobehavioral measures, rota rod and grip strength, were not consistently affected by 2,4-D ester. These studies confirm that 2,4-D ester produces behavioral toxicity, that tolerance develops to the 2,4-D ester-induced behavioral deficits with repeated exposures, and that a cellular mechanism appears to be responsible for the developed tolerance to 2,4-D ester.

  8. Performance evaluation and optimization of BM4D-AV denoising algorithm for cone-beam CT images

    NASA Astrophysics Data System (ADS)

    Huang, Kuidong; Tian, Xiaofei; Zhang, Dinghua; Zhang, Hua

    2015-12-01

    The broadening application of cone-beam Computed Tomography (CBCT) in medical diagnostics and nondestructive testing, necessitates advanced denoising algorithms for its 3D images. The block-matching and four dimensional filtering algorithm with adaptive variance (BM4D-AV) is applied to the 3D image denoising in this research. To optimize it, the key filtering parameters of the BM4D-AV algorithm are assessed firstly based on the simulated CBCT images and a table of optimized filtering parameters is obtained. Then, considering the complexity of the noise in realistic CBCT images, possible noise standard deviations in BM4D-AV are evaluated to attain the chosen principle for the realistic denoising. The results of corresponding experiments demonstrate that the BM4D-AV algorithm with optimized parameters presents excellent denosing effect on the realistic 3D CBCT images.

  9. SU-E-T-202: Comparison of 4D-Measurement-Guided Dose Reconstructions (MGDR) with COMPASS and OCTAVIUS 4D System

    SciTech Connect

    Leung, R; Wong, M; Lee, V; Law, G; Lee, K; Tung, S; Chan, M; Blanck, O

    2015-06-15

    Purpose: To cross-validate the MGDR of COMPASS (IBA dosimetry, GmbH, Germany) and OCTAVIUS 4D system (PTW, Freiburg, Germany). Methods: Volumetric-modulated arc plans (5 head-and-neck and 3 prostate) collapsed to 40° gantry on the OCTAVIUS 4D phantom in QA mode on Monaco v5.0 (Elekta, CMS, Maryland Heights, MO) were delivered on a Elekta Agility linac. This study was divided into two parts: (1) error-free measurements by gantry-mounted EvolutionXX 2D array were reconstructed in COMPASS (IBA dosimetry, GmbH, Germany), and by OCTAVIUS 1500 array in Versoft v6.1 (PTW, Freiburg, Germany) to obtain the 3D doses (COM4D and OCTA4D). COM4D and OCTA4D were compared to the raw measurement (OCTA3D) at the same detector plane for which OCTAVIUS 1500 was perpendicular to 0° gantry axis while the plans were delivered at gantry 40°; (2) beam steering errors of energy (Hump=-2%) and symmetry (2T=+2%) were introduced during the delivery of 5 plans to compare the MGDR doses COM4D-Hump (COM4D-2T), OCTA4D-Hump (OCTA4D-2T), with raw doses OCTA3D-Hump (OCTA3D-2T) and with OCTA3D to assess the error reconstruction and detection ability of MGDR tools. All comparisons used Υ-criteria of 2%(local dose)/2mm and 3%/3mm. Results: Averaged Υ passing rates were 85% and 96% for COM4D,and 94% and 99% for OCTA4D at 2%/2mm and 3%/3mm criteria respectively. For error reconstruction, COM4D-Hump (COM4D-2T) showed 81% (93%) at 2%/2mm and 94% (98%) at 3%/3mm, while OCTA4D-Hump (OCTA4D-2T) showed 96% (96%) at 2%/2mm and 99% (99%) at 3%/3mm. For error detection, OCTA3D doses were compared to COM4D-Hump (COM4D-2T) showing Υ passing rates of 93% (93%) at 2%/2mm and 98% (98%), and to OCTA4D-Hump (OCTA4D -2T) showing 94% (99%) at 2%/2mm and 81% (96%) at 3%/3mm, respectively. Conclusion: OCTAVIUS MGDR showed better agreement to raw measurements in both error- and error-free comparisons. COMPASS MGDR deviated from the raw measurements possibly owing to beam modeling uncertainty.

  10. Quantum effects and nonlocality in strongly coupled plasmonic nanowire dimers.

    PubMed

    Teperik, Tatiana V; Nordlander, Peter; Aizpurua, Javier; Borisov, Andrei G

    2013-11-04

    Using a fully quantum mechanical approach we study the optical response of a strongly coupled metallic nanowire dimer for variable separation widths of the junction between the nanowires. The translational invariance of the system allows to apply the time-dependent density functional theory (TDDFT) for nanowires of diameters up to 10 nm which is the largest size considered so far in quantum modeling of plasmonic dimers. By performing a detailed analysis of the optical extinction, induced charge densities, and near fields, we reveal the major nonlocal quantum effects determining the plasmonic modes and field enhancement in the system. These effects consist mainly of electron tunneling between the nanowires at small junction widths and dynamical screening. The TDDFT results are compared with results from classical electromagnetic calculations based on the local Drude and non-local hydrodynamic descriptions of the nanowire permittivity, as well as with results from a recently developed quantum corrected model. The latter provides a way to include quantum mechanical effects such as electron tunneling in standard classical electromagnetic simulations. We show that the TDDFT results can be thus retrieved semi-quantitatively within a classical framework. We also discuss the shortcomings of classical non-local hydrodynamic approaches. Finally, the implications of the actual position of the screening charge density at the gap interfaces are discussed in connection with plasmon ruler applications at subnanometric distances.

  11. 4D XCAT phantom for multimodality imaging research

    PubMed Central

    Segars, W. P.; Sturgeon, G.; Mendonca, S.; Grimes, Jason; Tsui, B. M. W.

    2010-01-01

    Purpose: The authors develop the 4D extended cardiac-torso (XCAT) phantom for multimodality imaging research. Methods: Highly detailed whole-body anatomies for the adult male and female were defined in the XCAT using nonuniform rational B-spline (NURBS) and subdivision surfaces based on segmentation of the Visible Male and Female anatomical datasets from the National Library of Medicine as well as patient datasets. Using the flexibility of these surfaces, the Visible Human anatomies were transformed to match body measurements and organ volumes for a 50th percentile (height and weight) male and female. The desired body measurements for the models were obtained using the PEOPLESIZE program that contains anthropometric dimensions categorized from 1st to the 99th percentile for US adults. The desired organ volumes were determined from ICRP Publication 89 [ICRP, ‘‘Basic anatomical and physiological data for use in radiological protection: reference values,” ICRP Publication 89 (International Commission on Radiological Protection, New York, NY, 2002)]. The male and female anatomies serve as standard templates upon which anatomical variations may be modeled in the XCAT through user-defined parameters. Parametrized models for the cardiac and respiratory motions were also incorporated into the XCAT based on high-resolution cardiac- and respiratory-gated multislice CT data. To demonstrate the usefulness of the phantom, the authors show example simulation studies in PET, SPECT, and CT using publicly available simulation packages. Results: As demonstrated in the pilot studies, the 4D XCAT (which includes thousands of anatomical structures) can produce realistic imaging data when combined with accurate models of the imaging process. With the flexibility of the NURBS surface primitives, any number of different anatomies, cardiac or respiratory motions or patterns, and spatial resolutions can be simulated to perform imaging research. Conclusions: With the ability to produce

  12. 4D XCAT phantom for multimodality imaging research

    SciTech Connect

    Segars, W. P.; Sturgeon, G.; Mendonca, S.; Grimes, Jason; Tsui, B. M. W.

    2010-09-15

    Purpose: The authors develop the 4D extended cardiac-torso (XCAT) phantom for multimodality imaging research. Methods: Highly detailed whole-body anatomies for the adult male and female were defined in the XCAT using nonuniform rational B-spline (NURBS) and subdivision surfaces based on segmentation of the Visible Male and Female anatomical datasets from the National Library of Medicine as well as patient datasets. Using the flexibility of these surfaces, the Visible Human anatomies were transformed to match body measurements and organ volumes for a 50th percentile (height and weight) male and female. The desired body measurements for the models were obtained using the PEOPLESIZE program that contains anthropometric dimensions categorized from 1st to the 99th percentile for US adults. The desired organ volumes were determined from ICRP Publication 89 [ICRP, ''Basic anatomical and physiological data for use in radiological protection: reference values,'' ICRP Publication 89 (International Commission on Radiological Protection, New York, NY, 2002)]. The male and female anatomies serve as standard templates upon which anatomical variations may be modeled in the XCAT through user-defined parameters. Parametrized models for the cardiac and respiratory motions were also incorporated into the XCAT based on high-resolution cardiac- and respiratory-gated multislice CT data. To demonstrate the usefulness of the phantom, the authors show example simulation studies in PET, SPECT, and CT using publicly available simulation packages. Results: As demonstrated in the pilot studies, the 4D XCAT (which includes thousands of anatomical structures) can produce realistic imaging data when combined with accurate models of the imaging process. With the flexibility of the NURBS surface primitives, any number of different anatomies, cardiac or respiratory motions or patterns, and spatial resolutions can be simulated to perform imaging research. Conclusions: With the ability to produce

  13. Homoclinic points of 2D and 4D maps via the parametrization method

    NASA Astrophysics Data System (ADS)

    Anastassiou, Stavros; Bountis, Tassos; Bäcker, Arnd

    2017-10-01

    An interesting problem in solid state physics is to compute discrete breather solutions in N coupled 1D Hamiltonian particle chains and investigate the richness of their interactions. One way to do this is to compute the homoclinic intersections of invariant manifolds of a saddle point located at the origin of a class of 2N -dimensional invertible maps. In this paper we apply the parametrization method to express these manifolds analytically as series expansions and compute their intersections numerically to high precision. We first carry out this procedure for a two-dimensional (2D) family of generalized Hénon maps (N=1 ), prove the existence of a hyperbolic set in the non-dissipative case and show that it is directly connected to the existence of a homoclinic orbit at the origin. Introducing dissipation we demonstrate that a homoclinic tangency occurs beyond which the homoclinic intersection disappears. Proceeding to N=2 , we use the same approach to accurately determine the homoclinic intersections of the invariant manifolds of a saddle point at the origin of a 4D map consisting of two coupled 2D cubic Hénon maps. For small values of the coupling we determine the homoclinic intersection, which ceases to exist once a certain amount of dissipation is present. We discuss an application of our results to the study of discrete breathers in two linearly coupled 1D particle chains with nearest-neighbor interactions and a Klein–Gordon on site potential.

  14. Low-dose 4D cone-beam CT via joint spatiotemporal regularization of tensor framelet and nonlocal total variation

    NASA Astrophysics Data System (ADS)

    Han, Hao; Gao, Hao; Xing, Lei

    2017-08-01

    Excessive radiation exposure is still a major concern in 4D cone-beam computed tomography (4D-CBCT) due to its prolonged scanning duration. Radiation dose can be effectively reduced by either under-sampling the x-ray projections or reducing the x-ray flux. However, 4D-CBCT reconstruction under such low-dose protocols is prone to image artifacts and noise. In this work, we propose a novel joint regularization-based iterative reconstruction method for low-dose 4D-CBCT. To tackle the under-sampling problem, we employ spatiotemporal tensor framelet (STF) regularization to take advantage of the spatiotemporal coherence of the patient anatomy in 4D images. To simultaneously suppress the image noise caused by photon starvation, we also incorporate spatiotemporal nonlocal total variation (SNTV) regularization to make use of the nonlocal self-recursiveness of anatomical structures in the spatial and temporal domains. Under the joint STF-SNTV regularization, the proposed iterative reconstruction approach is evaluated first using two digital phantoms and then using physical experiment data in the low-dose context of both under-sampled and noisy projections. Compared with existing approaches via either STF or SNTV regularization alone, the presented hybrid approach achieves improved image quality, and is particularly effective for the reconstruction of low-dose 4D-CBCT data that are not only sparse but noisy.

  15. Digit ratio (2D:4D) predicts sporting success among female fencers independent from physical, experience, and personality factors.

    PubMed

    Voracek, M; Reimer, B; Dressler, S G

    2010-12-01

    Research particularly focusing on male athletes and popular sports (running and soccer) suggests associations of lower (masculinized) second-to-fourth digit ratio (2D:4D), a putative marker of prenatal androgen action, with better sports performance. Studies focusing on women, non-mainstream sports, or controlling for covariates relevant for sporting success are still sparse. This study examined associations between 2D:4D and performance of both male and female athletes active in fencing (a non-mainstream sport dominated by male participants), while controlling for covariates. National fencing rankings and 2D:4D of 58 male and 41 female Austrian tournament fencers (mean age 24 years) were correlated. Among female, but not male, fencers, lower 2D:4D was related to better national fencing rankings. 2D:4D still accounted for incremental variance (12%) in fencing success, when the effects of salient performance factors (age, body mass index, years of fencing, training intensity, and the personality variables achievement, control, harm avoidance, and social potency) were controlled for (totaling 35% attributable variance). Athletes active in the most aggressive form (the sabre) had lower 2D:4D than those active in the other forms (épée and foil fencing). Sporting success in adult life might be partly prenatally programmed via long-lasting extragenital effects of testosterone. © 2009 John Wiley & Sons A/S.

  16. Spatiotemporal coupling effects in ultrashort pulses and their visualization

    NASA Astrophysics Data System (ADS)

    Rhodes, Michelle; Guang, Zhe; Trebino, Rick

    2017-02-01

    The general theory of first-order spatiotemporal